diff options
Diffstat (limited to 'drivers/net/wireguard')
31 files changed, 7104 insertions, 0 deletions
diff --git a/drivers/net/wireguard/Makefile b/drivers/net/wireguard/Makefile new file mode 100644 index 000000000..dbe1f8514 --- /dev/null +++ b/drivers/net/wireguard/Makefile @@ -0,0 +1,17 @@ +ccflags-y := -D'pr_fmt(fmt)=KBUILD_MODNAME ": " fmt' +ccflags-$(CONFIG_WIREGUARD_DEBUG) += -DDEBUG +wireguard-y := main.o +wireguard-y += noise.o +wireguard-y += device.o +wireguard-y += peer.o +wireguard-y += timers.o +wireguard-y += queueing.o +wireguard-y += send.o +wireguard-y += receive.o +wireguard-y += socket.o +wireguard-y += peerlookup.o +wireguard-y += allowedips.o +wireguard-y += ratelimiter.o +wireguard-y += cookie.o +wireguard-y += netlink.o +obj-$(CONFIG_WIREGUARD) := wireguard.o diff --git a/drivers/net/wireguard/allowedips.c b/drivers/net/wireguard/allowedips.c new file mode 100644 index 000000000..0ba714ca5 --- /dev/null +++ b/drivers/net/wireguard/allowedips.c @@ -0,0 +1,389 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#include "allowedips.h" +#include "peer.h" + +enum { MAX_ALLOWEDIPS_DEPTH = 129 }; + +static struct kmem_cache *node_cache; + +static void swap_endian(u8 *dst, const u8 *src, u8 bits) +{ + if (bits == 32) { + *(u32 *)dst = be32_to_cpu(*(const __be32 *)src); + } else if (bits == 128) { + ((u64 *)dst)[0] = be64_to_cpu(((const __be64 *)src)[0]); + ((u64 *)dst)[1] = be64_to_cpu(((const __be64 *)src)[1]); + } +} + +static void copy_and_assign_cidr(struct allowedips_node *node, const u8 *src, + u8 cidr, u8 bits) +{ + node->cidr = cidr; + node->bit_at_a = cidr / 8U; +#ifdef __LITTLE_ENDIAN + node->bit_at_a ^= (bits / 8U - 1U) % 8U; +#endif + node->bit_at_b = 7U - (cidr % 8U); + node->bitlen = bits; + memcpy(node->bits, src, bits / 8U); +} + +static inline u8 choose(struct allowedips_node *node, const u8 *key) +{ + return (key[node->bit_at_a] >> node->bit_at_b) & 1; +} + +static void push_rcu(struct allowedips_node **stack, + struct allowedips_node __rcu *p, unsigned int *len) +{ + if (rcu_access_pointer(p)) { + if (WARN_ON(IS_ENABLED(DEBUG) && *len >= MAX_ALLOWEDIPS_DEPTH)) + return; + stack[(*len)++] = rcu_dereference_raw(p); + } +} + +static void node_free_rcu(struct rcu_head *rcu) +{ + kmem_cache_free(node_cache, container_of(rcu, struct allowedips_node, rcu)); +} + +static void root_free_rcu(struct rcu_head *rcu) +{ + struct allowedips_node *node, *stack[MAX_ALLOWEDIPS_DEPTH] = { + container_of(rcu, struct allowedips_node, rcu) }; + unsigned int len = 1; + + while (len > 0 && (node = stack[--len])) { + push_rcu(stack, node->bit[0], &len); + push_rcu(stack, node->bit[1], &len); + kmem_cache_free(node_cache, node); + } +} + +static void root_remove_peer_lists(struct allowedips_node *root) +{ + struct allowedips_node *node, *stack[MAX_ALLOWEDIPS_DEPTH] = { root }; + unsigned int len = 1; + + while (len > 0 && (node = stack[--len])) { + push_rcu(stack, node->bit[0], &len); + push_rcu(stack, node->bit[1], &len); + if (rcu_access_pointer(node->peer)) + list_del(&node->peer_list); + } +} + +static unsigned int fls128(u64 a, u64 b) +{ + return a ? fls64(a) + 64U : fls64(b); +} + +static u8 common_bits(const struct allowedips_node *node, const u8 *key, + u8 bits) +{ + if (bits == 32) + return 32U - fls(*(const u32 *)node->bits ^ *(const u32 *)key); + else if (bits == 128) + return 128U - fls128( + *(const u64 *)&node->bits[0] ^ *(const u64 *)&key[0], + *(const u64 *)&node->bits[8] ^ *(const u64 *)&key[8]); + return 0; +} + +static bool prefix_matches(const struct allowedips_node *node, const u8 *key, + u8 bits) +{ + /* This could be much faster if it actually just compared the common + * bits properly, by precomputing a mask bswap(~0 << (32 - cidr)), and + * the rest, but it turns out that common_bits is already super fast on + * modern processors, even taking into account the unfortunate bswap. + * So, we just inline it like this instead. + */ + return common_bits(node, key, bits) >= node->cidr; +} + +static struct allowedips_node *find_node(struct allowedips_node *trie, u8 bits, + const u8 *key) +{ + struct allowedips_node *node = trie, *found = NULL; + + while (node && prefix_matches(node, key, bits)) { + if (rcu_access_pointer(node->peer)) + found = node; + if (node->cidr == bits) + break; + node = rcu_dereference_bh(node->bit[choose(node, key)]); + } + return found; +} + +/* Returns a strong reference to a peer */ +static struct wg_peer *lookup(struct allowedips_node __rcu *root, u8 bits, + const void *be_ip) +{ + /* Aligned so it can be passed to fls/fls64 */ + u8 ip[16] __aligned(__alignof(u64)); + struct allowedips_node *node; + struct wg_peer *peer = NULL; + + swap_endian(ip, be_ip, bits); + + rcu_read_lock_bh(); +retry: + node = find_node(rcu_dereference_bh(root), bits, ip); + if (node) { + peer = wg_peer_get_maybe_zero(rcu_dereference_bh(node->peer)); + if (!peer) + goto retry; + } + rcu_read_unlock_bh(); + return peer; +} + +static bool node_placement(struct allowedips_node __rcu *trie, const u8 *key, + u8 cidr, u8 bits, struct allowedips_node **rnode, + struct mutex *lock) +{ + struct allowedips_node *node = rcu_dereference_protected(trie, lockdep_is_held(lock)); + struct allowedips_node *parent = NULL; + bool exact = false; + + while (node && node->cidr <= cidr && prefix_matches(node, key, bits)) { + parent = node; + if (parent->cidr == cidr) { + exact = true; + break; + } + node = rcu_dereference_protected(parent->bit[choose(parent, key)], lockdep_is_held(lock)); + } + *rnode = parent; + return exact; +} + +static inline void connect_node(struct allowedips_node __rcu **parent, u8 bit, struct allowedips_node *node) +{ + node->parent_bit_packed = (unsigned long)parent | bit; + rcu_assign_pointer(*parent, node); +} + +static inline void choose_and_connect_node(struct allowedips_node *parent, struct allowedips_node *node) +{ + u8 bit = choose(parent, node->bits); + connect_node(&parent->bit[bit], bit, node); +} + +static int add(struct allowedips_node __rcu **trie, u8 bits, const u8 *key, + u8 cidr, struct wg_peer *peer, struct mutex *lock) +{ + struct allowedips_node *node, *parent, *down, *newnode; + + if (unlikely(cidr > bits || !peer)) + return -EINVAL; + + if (!rcu_access_pointer(*trie)) { + node = kmem_cache_zalloc(node_cache, GFP_KERNEL); + if (unlikely(!node)) + return -ENOMEM; + RCU_INIT_POINTER(node->peer, peer); + list_add_tail(&node->peer_list, &peer->allowedips_list); + copy_and_assign_cidr(node, key, cidr, bits); + connect_node(trie, 2, node); + return 0; + } + if (node_placement(*trie, key, cidr, bits, &node, lock)) { + rcu_assign_pointer(node->peer, peer); + list_move_tail(&node->peer_list, &peer->allowedips_list); + return 0; + } + + newnode = kmem_cache_zalloc(node_cache, GFP_KERNEL); + if (unlikely(!newnode)) + return -ENOMEM; + RCU_INIT_POINTER(newnode->peer, peer); + list_add_tail(&newnode->peer_list, &peer->allowedips_list); + copy_and_assign_cidr(newnode, key, cidr, bits); + + if (!node) { + down = rcu_dereference_protected(*trie, lockdep_is_held(lock)); + } else { + const u8 bit = choose(node, key); + down = rcu_dereference_protected(node->bit[bit], lockdep_is_held(lock)); + if (!down) { + connect_node(&node->bit[bit], bit, newnode); + return 0; + } + } + cidr = min(cidr, common_bits(down, key, bits)); + parent = node; + + if (newnode->cidr == cidr) { + choose_and_connect_node(newnode, down); + if (!parent) + connect_node(trie, 2, newnode); + else + choose_and_connect_node(parent, newnode); + return 0; + } + + node = kmem_cache_zalloc(node_cache, GFP_KERNEL); + if (unlikely(!node)) { + list_del(&newnode->peer_list); + kmem_cache_free(node_cache, newnode); + return -ENOMEM; + } + INIT_LIST_HEAD(&node->peer_list); + copy_and_assign_cidr(node, newnode->bits, cidr, bits); + + choose_and_connect_node(node, down); + choose_and_connect_node(node, newnode); + if (!parent) + connect_node(trie, 2, node); + else + choose_and_connect_node(parent, node); + return 0; +} + +void wg_allowedips_init(struct allowedips *table) +{ + table->root4 = table->root6 = NULL; + table->seq = 1; +} + +void wg_allowedips_free(struct allowedips *table, struct mutex *lock) +{ + struct allowedips_node __rcu *old4 = table->root4, *old6 = table->root6; + + ++table->seq; + RCU_INIT_POINTER(table->root4, NULL); + RCU_INIT_POINTER(table->root6, NULL); + if (rcu_access_pointer(old4)) { + struct allowedips_node *node = rcu_dereference_protected(old4, + lockdep_is_held(lock)); + + root_remove_peer_lists(node); + call_rcu(&node->rcu, root_free_rcu); + } + if (rcu_access_pointer(old6)) { + struct allowedips_node *node = rcu_dereference_protected(old6, + lockdep_is_held(lock)); + + root_remove_peer_lists(node); + call_rcu(&node->rcu, root_free_rcu); + } +} + +int wg_allowedips_insert_v4(struct allowedips *table, const struct in_addr *ip, + u8 cidr, struct wg_peer *peer, struct mutex *lock) +{ + /* Aligned so it can be passed to fls */ + u8 key[4] __aligned(__alignof(u32)); + + ++table->seq; + swap_endian(key, (const u8 *)ip, 32); + return add(&table->root4, 32, key, cidr, peer, lock); +} + +int wg_allowedips_insert_v6(struct allowedips *table, const struct in6_addr *ip, + u8 cidr, struct wg_peer *peer, struct mutex *lock) +{ + /* Aligned so it can be passed to fls64 */ + u8 key[16] __aligned(__alignof(u64)); + + ++table->seq; + swap_endian(key, (const u8 *)ip, 128); + return add(&table->root6, 128, key, cidr, peer, lock); +} + +void wg_allowedips_remove_by_peer(struct allowedips *table, + struct wg_peer *peer, struct mutex *lock) +{ + struct allowedips_node *node, *child, **parent_bit, *parent, *tmp; + bool free_parent; + + if (list_empty(&peer->allowedips_list)) + return; + ++table->seq; + list_for_each_entry_safe(node, tmp, &peer->allowedips_list, peer_list) { + list_del_init(&node->peer_list); + RCU_INIT_POINTER(node->peer, NULL); + if (node->bit[0] && node->bit[1]) + continue; + child = rcu_dereference_protected(node->bit[!rcu_access_pointer(node->bit[0])], + lockdep_is_held(lock)); + if (child) + child->parent_bit_packed = node->parent_bit_packed; + parent_bit = (struct allowedips_node **)(node->parent_bit_packed & ~3UL); + *parent_bit = child; + parent = (void *)parent_bit - + offsetof(struct allowedips_node, bit[node->parent_bit_packed & 1]); + free_parent = !rcu_access_pointer(node->bit[0]) && + !rcu_access_pointer(node->bit[1]) && + (node->parent_bit_packed & 3) <= 1 && + !rcu_access_pointer(parent->peer); + if (free_parent) + child = rcu_dereference_protected( + parent->bit[!(node->parent_bit_packed & 1)], + lockdep_is_held(lock)); + call_rcu(&node->rcu, node_free_rcu); + if (!free_parent) + continue; + if (child) + child->parent_bit_packed = parent->parent_bit_packed; + *(struct allowedips_node **)(parent->parent_bit_packed & ~3UL) = child; + call_rcu(&parent->rcu, node_free_rcu); + } +} + +int wg_allowedips_read_node(struct allowedips_node *node, u8 ip[16], u8 *cidr) +{ + const unsigned int cidr_bytes = DIV_ROUND_UP(node->cidr, 8U); + swap_endian(ip, node->bits, node->bitlen); + memset(ip + cidr_bytes, 0, node->bitlen / 8U - cidr_bytes); + if (node->cidr) + ip[cidr_bytes - 1U] &= ~0U << (-node->cidr % 8U); + + *cidr = node->cidr; + return node->bitlen == 32 ? AF_INET : AF_INET6; +} + +/* Returns a strong reference to a peer */ +struct wg_peer *wg_allowedips_lookup_dst(struct allowedips *table, + struct sk_buff *skb) +{ + if (skb->protocol == htons(ETH_P_IP)) + return lookup(table->root4, 32, &ip_hdr(skb)->daddr); + else if (skb->protocol == htons(ETH_P_IPV6)) + return lookup(table->root6, 128, &ipv6_hdr(skb)->daddr); + return NULL; +} + +/* Returns a strong reference to a peer */ +struct wg_peer *wg_allowedips_lookup_src(struct allowedips *table, + struct sk_buff *skb) +{ + if (skb->protocol == htons(ETH_P_IP)) + return lookup(table->root4, 32, &ip_hdr(skb)->saddr); + else if (skb->protocol == htons(ETH_P_IPV6)) + return lookup(table->root6, 128, &ipv6_hdr(skb)->saddr); + return NULL; +} + +int __init wg_allowedips_slab_init(void) +{ + node_cache = KMEM_CACHE(allowedips_node, 0); + return node_cache ? 0 : -ENOMEM; +} + +void wg_allowedips_slab_uninit(void) +{ + rcu_barrier(); + kmem_cache_destroy(node_cache); +} + +#include "selftest/allowedips.c" diff --git a/drivers/net/wireguard/allowedips.h b/drivers/net/wireguard/allowedips.h new file mode 100644 index 000000000..2346c797e --- /dev/null +++ b/drivers/net/wireguard/allowedips.h @@ -0,0 +1,59 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#ifndef _WG_ALLOWEDIPS_H +#define _WG_ALLOWEDIPS_H + +#include <linux/mutex.h> +#include <linux/ip.h> +#include <linux/ipv6.h> + +struct wg_peer; + +struct allowedips_node { + struct wg_peer __rcu *peer; + struct allowedips_node __rcu *bit[2]; + u8 cidr, bit_at_a, bit_at_b, bitlen; + u8 bits[16] __aligned(__alignof(u64)); + + /* Keep rarely used members at bottom to be beyond cache line. */ + unsigned long parent_bit_packed; + union { + struct list_head peer_list; + struct rcu_head rcu; + }; +}; + +struct allowedips { + struct allowedips_node __rcu *root4; + struct allowedips_node __rcu *root6; + u64 seq; +} __aligned(4); /* We pack the lower 2 bits of &root, but m68k only gives 16-bit alignment. */ + +void wg_allowedips_init(struct allowedips *table); +void wg_allowedips_free(struct allowedips *table, struct mutex *mutex); +int wg_allowedips_insert_v4(struct allowedips *table, const struct in_addr *ip, + u8 cidr, struct wg_peer *peer, struct mutex *lock); +int wg_allowedips_insert_v6(struct allowedips *table, const struct in6_addr *ip, + u8 cidr, struct wg_peer *peer, struct mutex *lock); +void wg_allowedips_remove_by_peer(struct allowedips *table, + struct wg_peer *peer, struct mutex *lock); +/* The ip input pointer should be __aligned(__alignof(u64))) */ +int wg_allowedips_read_node(struct allowedips_node *node, u8 ip[16], u8 *cidr); + +/* These return a strong reference to a peer: */ +struct wg_peer *wg_allowedips_lookup_dst(struct allowedips *table, + struct sk_buff *skb); +struct wg_peer *wg_allowedips_lookup_src(struct allowedips *table, + struct sk_buff *skb); + +#ifdef DEBUG +bool wg_allowedips_selftest(void); +#endif + +int wg_allowedips_slab_init(void); +void wg_allowedips_slab_uninit(void); + +#endif /* _WG_ALLOWEDIPS_H */ diff --git a/drivers/net/wireguard/cookie.c b/drivers/net/wireguard/cookie.c new file mode 100644 index 000000000..4956f0499 --- /dev/null +++ b/drivers/net/wireguard/cookie.c @@ -0,0 +1,236 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#include "cookie.h" +#include "peer.h" +#include "device.h" +#include "messages.h" +#include "ratelimiter.h" +#include "timers.h" + +#include <crypto/blake2s.h> +#include <crypto/chacha20poly1305.h> + +#include <net/ipv6.h> +#include <crypto/algapi.h> + +void wg_cookie_checker_init(struct cookie_checker *checker, + struct wg_device *wg) +{ + init_rwsem(&checker->secret_lock); + checker->secret_birthdate = ktime_get_coarse_boottime_ns(); + get_random_bytes(checker->secret, NOISE_HASH_LEN); + checker->device = wg; +} + +enum { COOKIE_KEY_LABEL_LEN = 8 }; +static const u8 mac1_key_label[COOKIE_KEY_LABEL_LEN] = "mac1----"; +static const u8 cookie_key_label[COOKIE_KEY_LABEL_LEN] = "cookie--"; + +static void precompute_key(u8 key[NOISE_SYMMETRIC_KEY_LEN], + const u8 pubkey[NOISE_PUBLIC_KEY_LEN], + const u8 label[COOKIE_KEY_LABEL_LEN]) +{ + struct blake2s_state blake; + + blake2s_init(&blake, NOISE_SYMMETRIC_KEY_LEN); + blake2s_update(&blake, label, COOKIE_KEY_LABEL_LEN); + blake2s_update(&blake, pubkey, NOISE_PUBLIC_KEY_LEN); + blake2s_final(&blake, key); +} + +/* Must hold peer->handshake.static_identity->lock */ +void wg_cookie_checker_precompute_device_keys(struct cookie_checker *checker) +{ + if (likely(checker->device->static_identity.has_identity)) { + precompute_key(checker->cookie_encryption_key, + checker->device->static_identity.static_public, + cookie_key_label); + precompute_key(checker->message_mac1_key, + checker->device->static_identity.static_public, + mac1_key_label); + } else { + memset(checker->cookie_encryption_key, 0, + NOISE_SYMMETRIC_KEY_LEN); + memset(checker->message_mac1_key, 0, NOISE_SYMMETRIC_KEY_LEN); + } +} + +void wg_cookie_checker_precompute_peer_keys(struct wg_peer *peer) +{ + precompute_key(peer->latest_cookie.cookie_decryption_key, + peer->handshake.remote_static, cookie_key_label); + precompute_key(peer->latest_cookie.message_mac1_key, + peer->handshake.remote_static, mac1_key_label); +} + +void wg_cookie_init(struct cookie *cookie) +{ + memset(cookie, 0, sizeof(*cookie)); + init_rwsem(&cookie->lock); +} + +static void compute_mac1(u8 mac1[COOKIE_LEN], const void *message, size_t len, + const u8 key[NOISE_SYMMETRIC_KEY_LEN]) +{ + len = len - sizeof(struct message_macs) + + offsetof(struct message_macs, mac1); + blake2s(mac1, message, key, COOKIE_LEN, len, NOISE_SYMMETRIC_KEY_LEN); +} + +static void compute_mac2(u8 mac2[COOKIE_LEN], const void *message, size_t len, + const u8 cookie[COOKIE_LEN]) +{ + len = len - sizeof(struct message_macs) + + offsetof(struct message_macs, mac2); + blake2s(mac2, message, cookie, COOKIE_LEN, len, COOKIE_LEN); +} + +static void make_cookie(u8 cookie[COOKIE_LEN], struct sk_buff *skb, + struct cookie_checker *checker) +{ + struct blake2s_state state; + + if (wg_birthdate_has_expired(checker->secret_birthdate, + COOKIE_SECRET_MAX_AGE)) { + down_write(&checker->secret_lock); + checker->secret_birthdate = ktime_get_coarse_boottime_ns(); + get_random_bytes(checker->secret, NOISE_HASH_LEN); + up_write(&checker->secret_lock); + } + + down_read(&checker->secret_lock); + + blake2s_init_key(&state, COOKIE_LEN, checker->secret, NOISE_HASH_LEN); + if (skb->protocol == htons(ETH_P_IP)) + blake2s_update(&state, (u8 *)&ip_hdr(skb)->saddr, + sizeof(struct in_addr)); + else if (skb->protocol == htons(ETH_P_IPV6)) + blake2s_update(&state, (u8 *)&ipv6_hdr(skb)->saddr, + sizeof(struct in6_addr)); + blake2s_update(&state, (u8 *)&udp_hdr(skb)->source, sizeof(__be16)); + blake2s_final(&state, cookie); + + up_read(&checker->secret_lock); +} + +enum cookie_mac_state wg_cookie_validate_packet(struct cookie_checker *checker, + struct sk_buff *skb, + bool check_cookie) +{ + struct message_macs *macs = (struct message_macs *) + (skb->data + skb->len - sizeof(*macs)); + enum cookie_mac_state ret; + u8 computed_mac[COOKIE_LEN]; + u8 cookie[COOKIE_LEN]; + + ret = INVALID_MAC; + compute_mac1(computed_mac, skb->data, skb->len, + checker->message_mac1_key); + if (crypto_memneq(computed_mac, macs->mac1, COOKIE_LEN)) + goto out; + + ret = VALID_MAC_BUT_NO_COOKIE; + + if (!check_cookie) + goto out; + + make_cookie(cookie, skb, checker); + + compute_mac2(computed_mac, skb->data, skb->len, cookie); + if (crypto_memneq(computed_mac, macs->mac2, COOKIE_LEN)) + goto out; + + ret = VALID_MAC_WITH_COOKIE_BUT_RATELIMITED; + if (!wg_ratelimiter_allow(skb, dev_net(checker->device->dev))) + goto out; + + ret = VALID_MAC_WITH_COOKIE; + +out: + return ret; +} + +void wg_cookie_add_mac_to_packet(void *message, size_t len, + struct wg_peer *peer) +{ + struct message_macs *macs = (struct message_macs *) + ((u8 *)message + len - sizeof(*macs)); + + down_write(&peer->latest_cookie.lock); + compute_mac1(macs->mac1, message, len, + peer->latest_cookie.message_mac1_key); + memcpy(peer->latest_cookie.last_mac1_sent, macs->mac1, COOKIE_LEN); + peer->latest_cookie.have_sent_mac1 = true; + up_write(&peer->latest_cookie.lock); + + down_read(&peer->latest_cookie.lock); + if (peer->latest_cookie.is_valid && + !wg_birthdate_has_expired(peer->latest_cookie.birthdate, + COOKIE_SECRET_MAX_AGE - COOKIE_SECRET_LATENCY)) + compute_mac2(macs->mac2, message, len, + peer->latest_cookie.cookie); + else + memset(macs->mac2, 0, COOKIE_LEN); + up_read(&peer->latest_cookie.lock); +} + +void wg_cookie_message_create(struct message_handshake_cookie *dst, + struct sk_buff *skb, __le32 index, + struct cookie_checker *checker) +{ + struct message_macs *macs = (struct message_macs *) + ((u8 *)skb->data + skb->len - sizeof(*macs)); + u8 cookie[COOKIE_LEN]; + + dst->header.type = cpu_to_le32(MESSAGE_HANDSHAKE_COOKIE); + dst->receiver_index = index; + get_random_bytes_wait(dst->nonce, COOKIE_NONCE_LEN); + + make_cookie(cookie, skb, checker); + xchacha20poly1305_encrypt(dst->encrypted_cookie, cookie, COOKIE_LEN, + macs->mac1, COOKIE_LEN, dst->nonce, + checker->cookie_encryption_key); +} + +void wg_cookie_message_consume(struct message_handshake_cookie *src, + struct wg_device *wg) +{ + struct wg_peer *peer = NULL; + u8 cookie[COOKIE_LEN]; + bool ret; + + if (unlikely(!wg_index_hashtable_lookup(wg->index_hashtable, + INDEX_HASHTABLE_HANDSHAKE | + INDEX_HASHTABLE_KEYPAIR, + src->receiver_index, &peer))) + return; + + down_read(&peer->latest_cookie.lock); + if (unlikely(!peer->latest_cookie.have_sent_mac1)) { + up_read(&peer->latest_cookie.lock); + goto out; + } + ret = xchacha20poly1305_decrypt( + cookie, src->encrypted_cookie, sizeof(src->encrypted_cookie), + peer->latest_cookie.last_mac1_sent, COOKIE_LEN, src->nonce, + peer->latest_cookie.cookie_decryption_key); + up_read(&peer->latest_cookie.lock); + + if (ret) { + down_write(&peer->latest_cookie.lock); + memcpy(peer->latest_cookie.cookie, cookie, COOKIE_LEN); + peer->latest_cookie.birthdate = ktime_get_coarse_boottime_ns(); + peer->latest_cookie.is_valid = true; + peer->latest_cookie.have_sent_mac1 = false; + up_write(&peer->latest_cookie.lock); + } else { + net_dbg_ratelimited("%s: Could not decrypt invalid cookie response\n", + wg->dev->name); + } + +out: + wg_peer_put(peer); +} diff --git a/drivers/net/wireguard/cookie.h b/drivers/net/wireguard/cookie.h new file mode 100644 index 000000000..c4bd61ca0 --- /dev/null +++ b/drivers/net/wireguard/cookie.h @@ -0,0 +1,59 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#ifndef _WG_COOKIE_H +#define _WG_COOKIE_H + +#include "messages.h" +#include <linux/rwsem.h> + +struct wg_peer; + +struct cookie_checker { + u8 secret[NOISE_HASH_LEN]; + u8 cookie_encryption_key[NOISE_SYMMETRIC_KEY_LEN]; + u8 message_mac1_key[NOISE_SYMMETRIC_KEY_LEN]; + u64 secret_birthdate; + struct rw_semaphore secret_lock; + struct wg_device *device; +}; + +struct cookie { + u64 birthdate; + bool is_valid; + u8 cookie[COOKIE_LEN]; + bool have_sent_mac1; + u8 last_mac1_sent[COOKIE_LEN]; + u8 cookie_decryption_key[NOISE_SYMMETRIC_KEY_LEN]; + u8 message_mac1_key[NOISE_SYMMETRIC_KEY_LEN]; + struct rw_semaphore lock; +}; + +enum cookie_mac_state { + INVALID_MAC, + VALID_MAC_BUT_NO_COOKIE, + VALID_MAC_WITH_COOKIE_BUT_RATELIMITED, + VALID_MAC_WITH_COOKIE +}; + +void wg_cookie_checker_init(struct cookie_checker *checker, + struct wg_device *wg); +void wg_cookie_checker_precompute_device_keys(struct cookie_checker *checker); +void wg_cookie_checker_precompute_peer_keys(struct wg_peer *peer); +void wg_cookie_init(struct cookie *cookie); + +enum cookie_mac_state wg_cookie_validate_packet(struct cookie_checker *checker, + struct sk_buff *skb, + bool check_cookie); +void wg_cookie_add_mac_to_packet(void *message, size_t len, + struct wg_peer *peer); + +void wg_cookie_message_create(struct message_handshake_cookie *src, + struct sk_buff *skb, __le32 index, + struct cookie_checker *checker); +void wg_cookie_message_consume(struct message_handshake_cookie *src, + struct wg_device *wg); + +#endif /* _WG_COOKIE_H */ diff --git a/drivers/net/wireguard/device.c b/drivers/net/wireguard/device.c new file mode 100644 index 000000000..895a621c9 --- /dev/null +++ b/drivers/net/wireguard/device.c @@ -0,0 +1,478 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#include "queueing.h" +#include "socket.h" +#include "timers.h" +#include "device.h" +#include "ratelimiter.h" +#include "peer.h" +#include "messages.h" + +#include <linux/module.h> +#include <linux/rtnetlink.h> +#include <linux/inet.h> +#include <linux/netdevice.h> +#include <linux/inetdevice.h> +#include <linux/if_arp.h> +#include <linux/icmp.h> +#include <linux/suspend.h> +#include <net/dst_metadata.h> +#include <net/icmp.h> +#include <net/rtnetlink.h> +#include <net/ip_tunnels.h> +#include <net/addrconf.h> + +static LIST_HEAD(device_list); + +static int wg_open(struct net_device *dev) +{ + struct in_device *dev_v4 = __in_dev_get_rtnl(dev); + struct inet6_dev *dev_v6 = __in6_dev_get(dev); + struct wg_device *wg = netdev_priv(dev); + struct wg_peer *peer; + int ret; + + if (dev_v4) { + /* At some point we might put this check near the ip_rt_send_ + * redirect call of ip_forward in net/ipv4/ip_forward.c, similar + * to the current secpath check. + */ + IN_DEV_CONF_SET(dev_v4, SEND_REDIRECTS, false); + IPV4_DEVCONF_ALL(dev_net(dev), SEND_REDIRECTS) = false; + } + if (dev_v6) + dev_v6->cnf.addr_gen_mode = IN6_ADDR_GEN_MODE_NONE; + + mutex_lock(&wg->device_update_lock); + ret = wg_socket_init(wg, wg->incoming_port); + if (ret < 0) + goto out; + list_for_each_entry(peer, &wg->peer_list, peer_list) { + wg_packet_send_staged_packets(peer); + if (peer->persistent_keepalive_interval) + wg_packet_send_keepalive(peer); + } +out: + mutex_unlock(&wg->device_update_lock); + return ret; +} + +static int wg_pm_notification(struct notifier_block *nb, unsigned long action, void *data) +{ + struct wg_device *wg; + struct wg_peer *peer; + + /* If the machine is constantly suspending and resuming, as part of + * its normal operation rather than as a somewhat rare event, then we + * don't actually want to clear keys. + */ + if (IS_ENABLED(CONFIG_PM_AUTOSLEEP) || + IS_ENABLED(CONFIG_PM_USERSPACE_AUTOSLEEP)) + return 0; + + if (action != PM_HIBERNATION_PREPARE && action != PM_SUSPEND_PREPARE) + return 0; + + rtnl_lock(); + list_for_each_entry(wg, &device_list, device_list) { + mutex_lock(&wg->device_update_lock); + list_for_each_entry(peer, &wg->peer_list, peer_list) { + del_timer(&peer->timer_zero_key_material); + wg_noise_handshake_clear(&peer->handshake); + wg_noise_keypairs_clear(&peer->keypairs); + } + mutex_unlock(&wg->device_update_lock); + } + rtnl_unlock(); + rcu_barrier(); + return 0; +} + +static struct notifier_block pm_notifier = { .notifier_call = wg_pm_notification }; + +static int wg_vm_notification(struct notifier_block *nb, unsigned long action, void *data) +{ + struct wg_device *wg; + struct wg_peer *peer; + + rtnl_lock(); + list_for_each_entry(wg, &device_list, device_list) { + mutex_lock(&wg->device_update_lock); + list_for_each_entry(peer, &wg->peer_list, peer_list) + wg_noise_expire_current_peer_keypairs(peer); + mutex_unlock(&wg->device_update_lock); + } + rtnl_unlock(); + return 0; +} + +static struct notifier_block vm_notifier = { .notifier_call = wg_vm_notification }; + +static int wg_stop(struct net_device *dev) +{ + struct wg_device *wg = netdev_priv(dev); + struct wg_peer *peer; + struct sk_buff *skb; + + mutex_lock(&wg->device_update_lock); + list_for_each_entry(peer, &wg->peer_list, peer_list) { + wg_packet_purge_staged_packets(peer); + wg_timers_stop(peer); + wg_noise_handshake_clear(&peer->handshake); + wg_noise_keypairs_clear(&peer->keypairs); + wg_noise_reset_last_sent_handshake(&peer->last_sent_handshake); + } + mutex_unlock(&wg->device_update_lock); + while ((skb = ptr_ring_consume(&wg->handshake_queue.ring)) != NULL) + kfree_skb(skb); + atomic_set(&wg->handshake_queue_len, 0); + wg_socket_reinit(wg, NULL, NULL); + return 0; +} + +static netdev_tx_t wg_xmit(struct sk_buff *skb, struct net_device *dev) +{ + struct wg_device *wg = netdev_priv(dev); + struct sk_buff_head packets; + struct wg_peer *peer; + struct sk_buff *next; + sa_family_t family; + u32 mtu; + int ret; + + if (unlikely(!wg_check_packet_protocol(skb))) { + ret = -EPROTONOSUPPORT; + net_dbg_ratelimited("%s: Invalid IP packet\n", dev->name); + goto err; + } + + peer = wg_allowedips_lookup_dst(&wg->peer_allowedips, skb); + if (unlikely(!peer)) { + ret = -ENOKEY; + if (skb->protocol == htons(ETH_P_IP)) + net_dbg_ratelimited("%s: No peer has allowed IPs matching %pI4\n", + dev->name, &ip_hdr(skb)->daddr); + else if (skb->protocol == htons(ETH_P_IPV6)) + net_dbg_ratelimited("%s: No peer has allowed IPs matching %pI6\n", + dev->name, &ipv6_hdr(skb)->daddr); + goto err_icmp; + } + + family = READ_ONCE(peer->endpoint.addr.sa_family); + if (unlikely(family != AF_INET && family != AF_INET6)) { + ret = -EDESTADDRREQ; + net_dbg_ratelimited("%s: No valid endpoint has been configured or discovered for peer %llu\n", + dev->name, peer->internal_id); + goto err_peer; + } + + mtu = skb_valid_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu; + + __skb_queue_head_init(&packets); + if (!skb_is_gso(skb)) { + skb_mark_not_on_list(skb); + } else { + struct sk_buff *segs = skb_gso_segment(skb, 0); + + if (IS_ERR(segs)) { + ret = PTR_ERR(segs); + goto err_peer; + } + dev_kfree_skb(skb); + skb = segs; + } + + skb_list_walk_safe(skb, skb, next) { + skb_mark_not_on_list(skb); + + skb = skb_share_check(skb, GFP_ATOMIC); + if (unlikely(!skb)) + continue; + + /* We only need to keep the original dst around for icmp, + * so at this point we're in a position to drop it. + */ + skb_dst_drop(skb); + + PACKET_CB(skb)->mtu = mtu; + + __skb_queue_tail(&packets, skb); + } + + spin_lock_bh(&peer->staged_packet_queue.lock); + /* If the queue is getting too big, we start removing the oldest packets + * until it's small again. We do this before adding the new packet, so + * we don't remove GSO segments that are in excess. + */ + while (skb_queue_len(&peer->staged_packet_queue) > MAX_STAGED_PACKETS) { + dev_kfree_skb(__skb_dequeue(&peer->staged_packet_queue)); + DEV_STATS_INC(dev, tx_dropped); + } + skb_queue_splice_tail(&packets, &peer->staged_packet_queue); + spin_unlock_bh(&peer->staged_packet_queue.lock); + + wg_packet_send_staged_packets(peer); + + wg_peer_put(peer); + return NETDEV_TX_OK; + +err_peer: + wg_peer_put(peer); +err_icmp: + if (skb->protocol == htons(ETH_P_IP)) + icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0); + else if (skb->protocol == htons(ETH_P_IPV6)) + icmpv6_ndo_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0); +err: + DEV_STATS_INC(dev, tx_errors); + kfree_skb(skb); + return ret; +} + +static const struct net_device_ops netdev_ops = { + .ndo_open = wg_open, + .ndo_stop = wg_stop, + .ndo_start_xmit = wg_xmit, + .ndo_get_stats64 = dev_get_tstats64 +}; + +static void wg_destruct(struct net_device *dev) +{ + struct wg_device *wg = netdev_priv(dev); + + rtnl_lock(); + list_del(&wg->device_list); + rtnl_unlock(); + mutex_lock(&wg->device_update_lock); + rcu_assign_pointer(wg->creating_net, NULL); + wg->incoming_port = 0; + wg_socket_reinit(wg, NULL, NULL); + /* The final references are cleared in the below calls to destroy_workqueue. */ + wg_peer_remove_all(wg); + destroy_workqueue(wg->handshake_receive_wq); + destroy_workqueue(wg->handshake_send_wq); + destroy_workqueue(wg->packet_crypt_wq); + wg_packet_queue_free(&wg->handshake_queue, true); + wg_packet_queue_free(&wg->decrypt_queue, false); + wg_packet_queue_free(&wg->encrypt_queue, false); + rcu_barrier(); /* Wait for all the peers to be actually freed. */ + wg_ratelimiter_uninit(); + memzero_explicit(&wg->static_identity, sizeof(wg->static_identity)); + free_percpu(dev->tstats); + kvfree(wg->index_hashtable); + kvfree(wg->peer_hashtable); + mutex_unlock(&wg->device_update_lock); + + pr_debug("%s: Interface destroyed\n", dev->name); + free_netdev(dev); +} + +static const struct device_type device_type = { .name = KBUILD_MODNAME }; + +static void wg_setup(struct net_device *dev) +{ + struct wg_device *wg = netdev_priv(dev); + enum { WG_NETDEV_FEATURES = NETIF_F_HW_CSUM | NETIF_F_RXCSUM | + NETIF_F_SG | NETIF_F_GSO | + NETIF_F_GSO_SOFTWARE | NETIF_F_HIGHDMA }; + const int overhead = MESSAGE_MINIMUM_LENGTH + sizeof(struct udphdr) + + max(sizeof(struct ipv6hdr), sizeof(struct iphdr)); + + dev->netdev_ops = &netdev_ops; + dev->header_ops = &ip_tunnel_header_ops; + dev->hard_header_len = 0; + dev->addr_len = 0; + dev->needed_headroom = DATA_PACKET_HEAD_ROOM; + dev->needed_tailroom = noise_encrypted_len(MESSAGE_PADDING_MULTIPLE); + dev->type = ARPHRD_NONE; + dev->flags = IFF_POINTOPOINT | IFF_NOARP; + dev->priv_flags |= IFF_NO_QUEUE; + dev->features |= NETIF_F_LLTX; + dev->features |= WG_NETDEV_FEATURES; + dev->hw_features |= WG_NETDEV_FEATURES; + dev->hw_enc_features |= WG_NETDEV_FEATURES; + dev->mtu = ETH_DATA_LEN - overhead; + dev->max_mtu = round_down(INT_MAX, MESSAGE_PADDING_MULTIPLE) - overhead; + + SET_NETDEV_DEVTYPE(dev, &device_type); + + /* We need to keep the dst around in case of icmp replies. */ + netif_keep_dst(dev); + + memset(wg, 0, sizeof(*wg)); + wg->dev = dev; +} + +static int wg_newlink(struct net *src_net, struct net_device *dev, + struct nlattr *tb[], struct nlattr *data[], + struct netlink_ext_ack *extack) +{ + struct wg_device *wg = netdev_priv(dev); + int ret = -ENOMEM; + + rcu_assign_pointer(wg->creating_net, src_net); + init_rwsem(&wg->static_identity.lock); + mutex_init(&wg->socket_update_lock); + mutex_init(&wg->device_update_lock); + wg_allowedips_init(&wg->peer_allowedips); + wg_cookie_checker_init(&wg->cookie_checker, wg); + INIT_LIST_HEAD(&wg->peer_list); + wg->device_update_gen = 1; + + wg->peer_hashtable = wg_pubkey_hashtable_alloc(); + if (!wg->peer_hashtable) + return ret; + + wg->index_hashtable = wg_index_hashtable_alloc(); + if (!wg->index_hashtable) + goto err_free_peer_hashtable; + + dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats); + if (!dev->tstats) + goto err_free_index_hashtable; + + wg->handshake_receive_wq = alloc_workqueue("wg-kex-%s", + WQ_CPU_INTENSIVE | WQ_FREEZABLE, 0, dev->name); + if (!wg->handshake_receive_wq) + goto err_free_tstats; + + wg->handshake_send_wq = alloc_workqueue("wg-kex-%s", + WQ_UNBOUND | WQ_FREEZABLE, 0, dev->name); + if (!wg->handshake_send_wq) + goto err_destroy_handshake_receive; + + wg->packet_crypt_wq = alloc_workqueue("wg-crypt-%s", + WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 0, dev->name); + if (!wg->packet_crypt_wq) + goto err_destroy_handshake_send; + + ret = wg_packet_queue_init(&wg->encrypt_queue, wg_packet_encrypt_worker, + MAX_QUEUED_PACKETS); + if (ret < 0) + goto err_destroy_packet_crypt; + + ret = wg_packet_queue_init(&wg->decrypt_queue, wg_packet_decrypt_worker, + MAX_QUEUED_PACKETS); + if (ret < 0) + goto err_free_encrypt_queue; + + ret = wg_packet_queue_init(&wg->handshake_queue, wg_packet_handshake_receive_worker, + MAX_QUEUED_INCOMING_HANDSHAKES); + if (ret < 0) + goto err_free_decrypt_queue; + + ret = wg_ratelimiter_init(); + if (ret < 0) + goto err_free_handshake_queue; + + ret = register_netdevice(dev); + if (ret < 0) + goto err_uninit_ratelimiter; + + list_add(&wg->device_list, &device_list); + + /* We wait until the end to assign priv_destructor, so that + * register_netdevice doesn't call it for us if it fails. + */ + dev->priv_destructor = wg_destruct; + + pr_debug("%s: Interface created\n", dev->name); + return ret; + +err_uninit_ratelimiter: + wg_ratelimiter_uninit(); +err_free_handshake_queue: + wg_packet_queue_free(&wg->handshake_queue, false); +err_free_decrypt_queue: + wg_packet_queue_free(&wg->decrypt_queue, false); +err_free_encrypt_queue: + wg_packet_queue_free(&wg->encrypt_queue, false); +err_destroy_packet_crypt: + destroy_workqueue(wg->packet_crypt_wq); +err_destroy_handshake_send: + destroy_workqueue(wg->handshake_send_wq); +err_destroy_handshake_receive: + destroy_workqueue(wg->handshake_receive_wq); +err_free_tstats: + free_percpu(dev->tstats); +err_free_index_hashtable: + kvfree(wg->index_hashtable); +err_free_peer_hashtable: + kvfree(wg->peer_hashtable); + return ret; +} + +static struct rtnl_link_ops link_ops __read_mostly = { + .kind = KBUILD_MODNAME, + .priv_size = sizeof(struct wg_device), + .setup = wg_setup, + .newlink = wg_newlink, +}; + +static void wg_netns_pre_exit(struct net *net) +{ + struct wg_device *wg; + struct wg_peer *peer; + + rtnl_lock(); + list_for_each_entry(wg, &device_list, device_list) { + if (rcu_access_pointer(wg->creating_net) == net) { + pr_debug("%s: Creating namespace exiting\n", wg->dev->name); + netif_carrier_off(wg->dev); + mutex_lock(&wg->device_update_lock); + rcu_assign_pointer(wg->creating_net, NULL); + wg_socket_reinit(wg, NULL, NULL); + list_for_each_entry(peer, &wg->peer_list, peer_list) + wg_socket_clear_peer_endpoint_src(peer); + mutex_unlock(&wg->device_update_lock); + } + } + rtnl_unlock(); +} + +static struct pernet_operations pernet_ops = { + .pre_exit = wg_netns_pre_exit +}; + +int __init wg_device_init(void) +{ + int ret; + + ret = register_pm_notifier(&pm_notifier); + if (ret) + return ret; + + ret = register_random_vmfork_notifier(&vm_notifier); + if (ret) + goto error_pm; + + ret = register_pernet_device(&pernet_ops); + if (ret) + goto error_vm; + + ret = rtnl_link_register(&link_ops); + if (ret) + goto error_pernet; + + return 0; + +error_pernet: + unregister_pernet_device(&pernet_ops); +error_vm: + unregister_random_vmfork_notifier(&vm_notifier); +error_pm: + unregister_pm_notifier(&pm_notifier); + return ret; +} + +void wg_device_uninit(void) +{ + rtnl_link_unregister(&link_ops); + unregister_pernet_device(&pernet_ops); + unregister_random_vmfork_notifier(&vm_notifier); + unregister_pm_notifier(&pm_notifier); + rcu_barrier(); +} diff --git a/drivers/net/wireguard/device.h b/drivers/net/wireguard/device.h new file mode 100644 index 000000000..43c7cebbf --- /dev/null +++ b/drivers/net/wireguard/device.h @@ -0,0 +1,62 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#ifndef _WG_DEVICE_H +#define _WG_DEVICE_H + +#include "noise.h" +#include "allowedips.h" +#include "peerlookup.h" +#include "cookie.h" + +#include <linux/types.h> +#include <linux/netdevice.h> +#include <linux/workqueue.h> +#include <linux/mutex.h> +#include <linux/net.h> +#include <linux/ptr_ring.h> + +struct wg_device; + +struct multicore_worker { + void *ptr; + struct work_struct work; +}; + +struct crypt_queue { + struct ptr_ring ring; + struct multicore_worker __percpu *worker; + int last_cpu; +}; + +struct prev_queue { + struct sk_buff *head, *tail, *peeked; + struct { struct sk_buff *next, *prev; } empty; // Match first 2 members of struct sk_buff. + atomic_t count; +}; + +struct wg_device { + struct net_device *dev; + struct crypt_queue encrypt_queue, decrypt_queue, handshake_queue; + struct sock __rcu *sock4, *sock6; + struct net __rcu *creating_net; + struct noise_static_identity static_identity; + struct workqueue_struct *packet_crypt_wq,*handshake_receive_wq, *handshake_send_wq; + struct cookie_checker cookie_checker; + struct pubkey_hashtable *peer_hashtable; + struct index_hashtable *index_hashtable; + struct allowedips peer_allowedips; + struct mutex device_update_lock, socket_update_lock; + struct list_head device_list, peer_list; + atomic_t handshake_queue_len; + unsigned int num_peers, device_update_gen; + u32 fwmark; + u16 incoming_port; +}; + +int wg_device_init(void); +void wg_device_uninit(void); + +#endif /* _WG_DEVICE_H */ diff --git a/drivers/net/wireguard/main.c b/drivers/net/wireguard/main.c new file mode 100644 index 000000000..ee4da9ab8 --- /dev/null +++ b/drivers/net/wireguard/main.c @@ -0,0 +1,78 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#include "version.h" +#include "device.h" +#include "noise.h" +#include "queueing.h" +#include "ratelimiter.h" +#include "netlink.h" + +#include <uapi/linux/wireguard.h> + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/genetlink.h> +#include <net/rtnetlink.h> + +static int __init wg_mod_init(void) +{ + int ret; + + ret = wg_allowedips_slab_init(); + if (ret < 0) + goto err_allowedips; + +#ifdef DEBUG + ret = -ENOTRECOVERABLE; + if (!wg_allowedips_selftest() || !wg_packet_counter_selftest() || + !wg_ratelimiter_selftest()) + goto err_peer; +#endif + wg_noise_init(); + + ret = wg_peer_init(); + if (ret < 0) + goto err_peer; + + ret = wg_device_init(); + if (ret < 0) + goto err_device; + + ret = wg_genetlink_init(); + if (ret < 0) + goto err_netlink; + + pr_info("WireGuard " WIREGUARD_VERSION " loaded. See www.wireguard.com for information.\n"); + pr_info("Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.\n"); + + return 0; + +err_netlink: + wg_device_uninit(); +err_device: + wg_peer_uninit(); +err_peer: + wg_allowedips_slab_uninit(); +err_allowedips: + return ret; +} + +static void __exit wg_mod_exit(void) +{ + wg_genetlink_uninit(); + wg_device_uninit(); + wg_peer_uninit(); + wg_allowedips_slab_uninit(); +} + +module_init(wg_mod_init); +module_exit(wg_mod_exit); +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("WireGuard secure network tunnel"); +MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>"); +MODULE_VERSION(WIREGUARD_VERSION); +MODULE_ALIAS_RTNL_LINK(KBUILD_MODNAME); +MODULE_ALIAS_GENL_FAMILY(WG_GENL_NAME); diff --git a/drivers/net/wireguard/messages.h b/drivers/net/wireguard/messages.h new file mode 100644 index 000000000..208da7267 --- /dev/null +++ b/drivers/net/wireguard/messages.h @@ -0,0 +1,128 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#ifndef _WG_MESSAGES_H +#define _WG_MESSAGES_H + +#include <crypto/curve25519.h> +#include <crypto/chacha20poly1305.h> +#include <crypto/blake2s.h> + +#include <linux/kernel.h> +#include <linux/param.h> +#include <linux/skbuff.h> + +enum noise_lengths { + NOISE_PUBLIC_KEY_LEN = CURVE25519_KEY_SIZE, + NOISE_SYMMETRIC_KEY_LEN = CHACHA20POLY1305_KEY_SIZE, + NOISE_TIMESTAMP_LEN = sizeof(u64) + sizeof(u32), + NOISE_AUTHTAG_LEN = CHACHA20POLY1305_AUTHTAG_SIZE, + NOISE_HASH_LEN = BLAKE2S_HASH_SIZE +}; + +#define noise_encrypted_len(plain_len) ((plain_len) + NOISE_AUTHTAG_LEN) + +enum cookie_values { + COOKIE_SECRET_MAX_AGE = 2 * 60, + COOKIE_SECRET_LATENCY = 5, + COOKIE_NONCE_LEN = XCHACHA20POLY1305_NONCE_SIZE, + COOKIE_LEN = 16 +}; + +enum counter_values { + COUNTER_BITS_TOTAL = 8192, + COUNTER_REDUNDANT_BITS = BITS_PER_LONG, + COUNTER_WINDOW_SIZE = COUNTER_BITS_TOTAL - COUNTER_REDUNDANT_BITS +}; + +enum limits { + REKEY_AFTER_MESSAGES = 1ULL << 60, + REJECT_AFTER_MESSAGES = U64_MAX - COUNTER_WINDOW_SIZE - 1, + REKEY_TIMEOUT = 5, + REKEY_TIMEOUT_JITTER_MAX_JIFFIES = HZ / 3, + REKEY_AFTER_TIME = 120, + REJECT_AFTER_TIME = 180, + INITIATIONS_PER_SECOND = 50, + MAX_PEERS_PER_DEVICE = 1U << 20, + KEEPALIVE_TIMEOUT = 10, + MAX_TIMER_HANDSHAKES = 90 / REKEY_TIMEOUT, + MAX_QUEUED_INCOMING_HANDSHAKES = 4096, /* TODO: replace this with DQL */ + MAX_STAGED_PACKETS = 128, + MAX_QUEUED_PACKETS = 1024 /* TODO: replace this with DQL */ +}; + +enum message_type { + MESSAGE_INVALID = 0, + MESSAGE_HANDSHAKE_INITIATION = 1, + MESSAGE_HANDSHAKE_RESPONSE = 2, + MESSAGE_HANDSHAKE_COOKIE = 3, + MESSAGE_DATA = 4 +}; + +struct message_header { + /* The actual layout of this that we want is: + * u8 type + * u8 reserved_zero[3] + * + * But it turns out that by encoding this as little endian, + * we achieve the same thing, and it makes checking faster. + */ + __le32 type; +}; + +struct message_macs { + u8 mac1[COOKIE_LEN]; + u8 mac2[COOKIE_LEN]; +}; + +struct message_handshake_initiation { + struct message_header header; + __le32 sender_index; + u8 unencrypted_ephemeral[NOISE_PUBLIC_KEY_LEN]; + u8 encrypted_static[noise_encrypted_len(NOISE_PUBLIC_KEY_LEN)]; + u8 encrypted_timestamp[noise_encrypted_len(NOISE_TIMESTAMP_LEN)]; + struct message_macs macs; +}; + +struct message_handshake_response { + struct message_header header; + __le32 sender_index; + __le32 receiver_index; + u8 unencrypted_ephemeral[NOISE_PUBLIC_KEY_LEN]; + u8 encrypted_nothing[noise_encrypted_len(0)]; + struct message_macs macs; +}; + +struct message_handshake_cookie { + struct message_header header; + __le32 receiver_index; + u8 nonce[COOKIE_NONCE_LEN]; + u8 encrypted_cookie[noise_encrypted_len(COOKIE_LEN)]; +}; + +struct message_data { + struct message_header header; + __le32 key_idx; + __le64 counter; + u8 encrypted_data[]; +}; + +#define message_data_len(plain_len) \ + (noise_encrypted_len(plain_len) + sizeof(struct message_data)) + +enum message_alignments { + MESSAGE_PADDING_MULTIPLE = 16, + MESSAGE_MINIMUM_LENGTH = message_data_len(0) +}; + +#define SKB_HEADER_LEN \ + (max(sizeof(struct iphdr), sizeof(struct ipv6hdr)) + \ + sizeof(struct udphdr) + NET_SKB_PAD) +#define DATA_PACKET_HEAD_ROOM \ + ALIGN(sizeof(struct message_data) + SKB_HEADER_LEN, 4) + +enum { HANDSHAKE_DSCP = 0x88 /* AF41, plus 00 ECN */ }; + +#endif /* _WG_MESSAGES_H */ diff --git a/drivers/net/wireguard/netlink.c b/drivers/net/wireguard/netlink.c new file mode 100644 index 000000000..6d1bd9f52 --- /dev/null +++ b/drivers/net/wireguard/netlink.c @@ -0,0 +1,644 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#include "netlink.h" +#include "device.h" +#include "peer.h" +#include "socket.h" +#include "queueing.h" +#include "messages.h" + +#include <uapi/linux/wireguard.h> + +#include <linux/if.h> +#include <net/genetlink.h> +#include <net/sock.h> +#include <crypto/algapi.h> + +static struct genl_family genl_family; + +static const struct nla_policy device_policy[WGDEVICE_A_MAX + 1] = { + [WGDEVICE_A_IFINDEX] = { .type = NLA_U32 }, + [WGDEVICE_A_IFNAME] = { .type = NLA_NUL_STRING, .len = IFNAMSIZ - 1 }, + [WGDEVICE_A_PRIVATE_KEY] = NLA_POLICY_EXACT_LEN(NOISE_PUBLIC_KEY_LEN), + [WGDEVICE_A_PUBLIC_KEY] = NLA_POLICY_EXACT_LEN(NOISE_PUBLIC_KEY_LEN), + [WGDEVICE_A_FLAGS] = { .type = NLA_U32 }, + [WGDEVICE_A_LISTEN_PORT] = { .type = NLA_U16 }, + [WGDEVICE_A_FWMARK] = { .type = NLA_U32 }, + [WGDEVICE_A_PEERS] = { .type = NLA_NESTED } +}; + +static const struct nla_policy peer_policy[WGPEER_A_MAX + 1] = { + [WGPEER_A_PUBLIC_KEY] = NLA_POLICY_EXACT_LEN(NOISE_PUBLIC_KEY_LEN), + [WGPEER_A_PRESHARED_KEY] = NLA_POLICY_EXACT_LEN(NOISE_SYMMETRIC_KEY_LEN), + [WGPEER_A_FLAGS] = { .type = NLA_U32 }, + [WGPEER_A_ENDPOINT] = NLA_POLICY_MIN_LEN(sizeof(struct sockaddr)), + [WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL] = { .type = NLA_U16 }, + [WGPEER_A_LAST_HANDSHAKE_TIME] = NLA_POLICY_EXACT_LEN(sizeof(struct __kernel_timespec)), + [WGPEER_A_RX_BYTES] = { .type = NLA_U64 }, + [WGPEER_A_TX_BYTES] = { .type = NLA_U64 }, + [WGPEER_A_ALLOWEDIPS] = { .type = NLA_NESTED }, + [WGPEER_A_PROTOCOL_VERSION] = { .type = NLA_U32 } +}; + +static const struct nla_policy allowedip_policy[WGALLOWEDIP_A_MAX + 1] = { + [WGALLOWEDIP_A_FAMILY] = { .type = NLA_U16 }, + [WGALLOWEDIP_A_IPADDR] = NLA_POLICY_MIN_LEN(sizeof(struct in_addr)), + [WGALLOWEDIP_A_CIDR_MASK] = { .type = NLA_U8 } +}; + +static struct wg_device *lookup_interface(struct nlattr **attrs, + struct sk_buff *skb) +{ + struct net_device *dev = NULL; + + if (!attrs[WGDEVICE_A_IFINDEX] == !attrs[WGDEVICE_A_IFNAME]) + return ERR_PTR(-EBADR); + if (attrs[WGDEVICE_A_IFINDEX]) + dev = dev_get_by_index(sock_net(skb->sk), + nla_get_u32(attrs[WGDEVICE_A_IFINDEX])); + else if (attrs[WGDEVICE_A_IFNAME]) + dev = dev_get_by_name(sock_net(skb->sk), + nla_data(attrs[WGDEVICE_A_IFNAME])); + if (!dev) + return ERR_PTR(-ENODEV); + if (!dev->rtnl_link_ops || !dev->rtnl_link_ops->kind || + strcmp(dev->rtnl_link_ops->kind, KBUILD_MODNAME)) { + dev_put(dev); + return ERR_PTR(-EOPNOTSUPP); + } + return netdev_priv(dev); +} + +static int get_allowedips(struct sk_buff *skb, const u8 *ip, u8 cidr, + int family) +{ + struct nlattr *allowedip_nest; + + allowedip_nest = nla_nest_start(skb, 0); + if (!allowedip_nest) + return -EMSGSIZE; + + if (nla_put_u8(skb, WGALLOWEDIP_A_CIDR_MASK, cidr) || + nla_put_u16(skb, WGALLOWEDIP_A_FAMILY, family) || + nla_put(skb, WGALLOWEDIP_A_IPADDR, family == AF_INET6 ? + sizeof(struct in6_addr) : sizeof(struct in_addr), ip)) { + nla_nest_cancel(skb, allowedip_nest); + return -EMSGSIZE; + } + + nla_nest_end(skb, allowedip_nest); + return 0; +} + +struct dump_ctx { + struct wg_device *wg; + struct wg_peer *next_peer; + u64 allowedips_seq; + struct allowedips_node *next_allowedip; +}; + +#define DUMP_CTX(cb) ((struct dump_ctx *)(cb)->args) + +static int +get_peer(struct wg_peer *peer, struct sk_buff *skb, struct dump_ctx *ctx) +{ + + struct nlattr *allowedips_nest, *peer_nest = nla_nest_start(skb, 0); + struct allowedips_node *allowedips_node = ctx->next_allowedip; + bool fail; + + if (!peer_nest) + return -EMSGSIZE; + + down_read(&peer->handshake.lock); + fail = nla_put(skb, WGPEER_A_PUBLIC_KEY, NOISE_PUBLIC_KEY_LEN, + peer->handshake.remote_static); + up_read(&peer->handshake.lock); + if (fail) + goto err; + + if (!allowedips_node) { + const struct __kernel_timespec last_handshake = { + .tv_sec = peer->walltime_last_handshake.tv_sec, + .tv_nsec = peer->walltime_last_handshake.tv_nsec + }; + + down_read(&peer->handshake.lock); + fail = nla_put(skb, WGPEER_A_PRESHARED_KEY, + NOISE_SYMMETRIC_KEY_LEN, + peer->handshake.preshared_key); + up_read(&peer->handshake.lock); + if (fail) + goto err; + + if (nla_put(skb, WGPEER_A_LAST_HANDSHAKE_TIME, + sizeof(last_handshake), &last_handshake) || + nla_put_u16(skb, WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL, + peer->persistent_keepalive_interval) || + nla_put_u64_64bit(skb, WGPEER_A_TX_BYTES, peer->tx_bytes, + WGPEER_A_UNSPEC) || + nla_put_u64_64bit(skb, WGPEER_A_RX_BYTES, peer->rx_bytes, + WGPEER_A_UNSPEC) || + nla_put_u32(skb, WGPEER_A_PROTOCOL_VERSION, 1)) + goto err; + + read_lock_bh(&peer->endpoint_lock); + if (peer->endpoint.addr.sa_family == AF_INET) + fail = nla_put(skb, WGPEER_A_ENDPOINT, + sizeof(peer->endpoint.addr4), + &peer->endpoint.addr4); + else if (peer->endpoint.addr.sa_family == AF_INET6) + fail = nla_put(skb, WGPEER_A_ENDPOINT, + sizeof(peer->endpoint.addr6), + &peer->endpoint.addr6); + read_unlock_bh(&peer->endpoint_lock); + if (fail) + goto err; + allowedips_node = + list_first_entry_or_null(&peer->allowedips_list, + struct allowedips_node, peer_list); + } + if (!allowedips_node) + goto no_allowedips; + if (!ctx->allowedips_seq) + ctx->allowedips_seq = peer->device->peer_allowedips.seq; + else if (ctx->allowedips_seq != peer->device->peer_allowedips.seq) + goto no_allowedips; + + allowedips_nest = nla_nest_start(skb, WGPEER_A_ALLOWEDIPS); + if (!allowedips_nest) + goto err; + + list_for_each_entry_from(allowedips_node, &peer->allowedips_list, + peer_list) { + u8 cidr, ip[16] __aligned(__alignof(u64)); + int family; + + family = wg_allowedips_read_node(allowedips_node, ip, &cidr); + if (get_allowedips(skb, ip, cidr, family)) { + nla_nest_end(skb, allowedips_nest); + nla_nest_end(skb, peer_nest); + ctx->next_allowedip = allowedips_node; + return -EMSGSIZE; + } + } + nla_nest_end(skb, allowedips_nest); +no_allowedips: + nla_nest_end(skb, peer_nest); + ctx->next_allowedip = NULL; + ctx->allowedips_seq = 0; + return 0; +err: + nla_nest_cancel(skb, peer_nest); + return -EMSGSIZE; +} + +static int wg_get_device_start(struct netlink_callback *cb) +{ + struct wg_device *wg; + + wg = lookup_interface(genl_dumpit_info(cb)->attrs, cb->skb); + if (IS_ERR(wg)) + return PTR_ERR(wg); + DUMP_CTX(cb)->wg = wg; + return 0; +} + +static int wg_get_device_dump(struct sk_buff *skb, struct netlink_callback *cb) +{ + struct wg_peer *peer, *next_peer_cursor; + struct dump_ctx *ctx = DUMP_CTX(cb); + struct wg_device *wg = ctx->wg; + struct nlattr *peers_nest; + int ret = -EMSGSIZE; + bool done = true; + void *hdr; + + rtnl_lock(); + mutex_lock(&wg->device_update_lock); + cb->seq = wg->device_update_gen; + next_peer_cursor = ctx->next_peer; + + hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, + &genl_family, NLM_F_MULTI, WG_CMD_GET_DEVICE); + if (!hdr) + goto out; + genl_dump_check_consistent(cb, hdr); + + if (!ctx->next_peer) { + if (nla_put_u16(skb, WGDEVICE_A_LISTEN_PORT, + wg->incoming_port) || + nla_put_u32(skb, WGDEVICE_A_FWMARK, wg->fwmark) || + nla_put_u32(skb, WGDEVICE_A_IFINDEX, wg->dev->ifindex) || + nla_put_string(skb, WGDEVICE_A_IFNAME, wg->dev->name)) + goto out; + + down_read(&wg->static_identity.lock); + if (wg->static_identity.has_identity) { + if (nla_put(skb, WGDEVICE_A_PRIVATE_KEY, + NOISE_PUBLIC_KEY_LEN, + wg->static_identity.static_private) || + nla_put(skb, WGDEVICE_A_PUBLIC_KEY, + NOISE_PUBLIC_KEY_LEN, + wg->static_identity.static_public)) { + up_read(&wg->static_identity.lock); + goto out; + } + } + up_read(&wg->static_identity.lock); + } + + peers_nest = nla_nest_start(skb, WGDEVICE_A_PEERS); + if (!peers_nest) + goto out; + ret = 0; + /* If the last cursor was removed via list_del_init in peer_remove, then + * we just treat this the same as there being no more peers left. The + * reason is that seq_nr should indicate to userspace that this isn't a + * coherent dump anyway, so they'll try again. + */ + if (list_empty(&wg->peer_list) || + (ctx->next_peer && list_empty(&ctx->next_peer->peer_list))) { + nla_nest_cancel(skb, peers_nest); + goto out; + } + lockdep_assert_held(&wg->device_update_lock); + peer = list_prepare_entry(ctx->next_peer, &wg->peer_list, peer_list); + list_for_each_entry_continue(peer, &wg->peer_list, peer_list) { + if (get_peer(peer, skb, ctx)) { + done = false; + break; + } + next_peer_cursor = peer; + } + nla_nest_end(skb, peers_nest); + +out: + if (!ret && !done && next_peer_cursor) + wg_peer_get(next_peer_cursor); + wg_peer_put(ctx->next_peer); + mutex_unlock(&wg->device_update_lock); + rtnl_unlock(); + + if (ret) { + genlmsg_cancel(skb, hdr); + return ret; + } + genlmsg_end(skb, hdr); + if (done) { + ctx->next_peer = NULL; + return 0; + } + ctx->next_peer = next_peer_cursor; + return skb->len; + + /* At this point, we can't really deal ourselves with safely zeroing out + * the private key material after usage. This will need an additional API + * in the kernel for marking skbs as zero_on_free. + */ +} + +static int wg_get_device_done(struct netlink_callback *cb) +{ + struct dump_ctx *ctx = DUMP_CTX(cb); + + if (ctx->wg) + dev_put(ctx->wg->dev); + wg_peer_put(ctx->next_peer); + return 0; +} + +static int set_port(struct wg_device *wg, u16 port) +{ + struct wg_peer *peer; + + if (wg->incoming_port == port) + return 0; + list_for_each_entry(peer, &wg->peer_list, peer_list) + wg_socket_clear_peer_endpoint_src(peer); + if (!netif_running(wg->dev)) { + wg->incoming_port = port; + return 0; + } + return wg_socket_init(wg, port); +} + +static int set_allowedip(struct wg_peer *peer, struct nlattr **attrs) +{ + int ret = -EINVAL; + u16 family; + u8 cidr; + + if (!attrs[WGALLOWEDIP_A_FAMILY] || !attrs[WGALLOWEDIP_A_IPADDR] || + !attrs[WGALLOWEDIP_A_CIDR_MASK]) + return ret; + family = nla_get_u16(attrs[WGALLOWEDIP_A_FAMILY]); + cidr = nla_get_u8(attrs[WGALLOWEDIP_A_CIDR_MASK]); + + if (family == AF_INET && cidr <= 32 && + nla_len(attrs[WGALLOWEDIP_A_IPADDR]) == sizeof(struct in_addr)) + ret = wg_allowedips_insert_v4( + &peer->device->peer_allowedips, + nla_data(attrs[WGALLOWEDIP_A_IPADDR]), cidr, peer, + &peer->device->device_update_lock); + else if (family == AF_INET6 && cidr <= 128 && + nla_len(attrs[WGALLOWEDIP_A_IPADDR]) == sizeof(struct in6_addr)) + ret = wg_allowedips_insert_v6( + &peer->device->peer_allowedips, + nla_data(attrs[WGALLOWEDIP_A_IPADDR]), cidr, peer, + &peer->device->device_update_lock); + + return ret; +} + +static int set_peer(struct wg_device *wg, struct nlattr **attrs) +{ + u8 *public_key = NULL, *preshared_key = NULL; + struct wg_peer *peer = NULL; + u32 flags = 0; + int ret; + + ret = -EINVAL; + if (attrs[WGPEER_A_PUBLIC_KEY] && + nla_len(attrs[WGPEER_A_PUBLIC_KEY]) == NOISE_PUBLIC_KEY_LEN) + public_key = nla_data(attrs[WGPEER_A_PUBLIC_KEY]); + else + goto out; + if (attrs[WGPEER_A_PRESHARED_KEY] && + nla_len(attrs[WGPEER_A_PRESHARED_KEY]) == NOISE_SYMMETRIC_KEY_LEN) + preshared_key = nla_data(attrs[WGPEER_A_PRESHARED_KEY]); + + if (attrs[WGPEER_A_FLAGS]) + flags = nla_get_u32(attrs[WGPEER_A_FLAGS]); + ret = -EOPNOTSUPP; + if (flags & ~__WGPEER_F_ALL) + goto out; + + ret = -EPFNOSUPPORT; + if (attrs[WGPEER_A_PROTOCOL_VERSION]) { + if (nla_get_u32(attrs[WGPEER_A_PROTOCOL_VERSION]) != 1) + goto out; + } + + peer = wg_pubkey_hashtable_lookup(wg->peer_hashtable, + nla_data(attrs[WGPEER_A_PUBLIC_KEY])); + ret = 0; + if (!peer) { /* Peer doesn't exist yet. Add a new one. */ + if (flags & (WGPEER_F_REMOVE_ME | WGPEER_F_UPDATE_ONLY)) + goto out; + + /* The peer is new, so there aren't allowed IPs to remove. */ + flags &= ~WGPEER_F_REPLACE_ALLOWEDIPS; + + down_read(&wg->static_identity.lock); + if (wg->static_identity.has_identity && + !memcmp(nla_data(attrs[WGPEER_A_PUBLIC_KEY]), + wg->static_identity.static_public, + NOISE_PUBLIC_KEY_LEN)) { + /* We silently ignore peers that have the same public + * key as the device. The reason we do it silently is + * that we'd like for people to be able to reuse the + * same set of API calls across peers. + */ + up_read(&wg->static_identity.lock); + ret = 0; + goto out; + } + up_read(&wg->static_identity.lock); + + peer = wg_peer_create(wg, public_key, preshared_key); + if (IS_ERR(peer)) { + ret = PTR_ERR(peer); + peer = NULL; + goto out; + } + /* Take additional reference, as though we've just been + * looked up. + */ + wg_peer_get(peer); + } + + if (flags & WGPEER_F_REMOVE_ME) { + wg_peer_remove(peer); + goto out; + } + + if (preshared_key) { + down_write(&peer->handshake.lock); + memcpy(&peer->handshake.preshared_key, preshared_key, + NOISE_SYMMETRIC_KEY_LEN); + up_write(&peer->handshake.lock); + } + + if (attrs[WGPEER_A_ENDPOINT]) { + struct sockaddr *addr = nla_data(attrs[WGPEER_A_ENDPOINT]); + size_t len = nla_len(attrs[WGPEER_A_ENDPOINT]); + struct endpoint endpoint = { { { 0 } } }; + + if (len == sizeof(struct sockaddr_in) && addr->sa_family == AF_INET) { + endpoint.addr4 = *(struct sockaddr_in *)addr; + wg_socket_set_peer_endpoint(peer, &endpoint); + } else if (len == sizeof(struct sockaddr_in6) && addr->sa_family == AF_INET6) { + endpoint.addr6 = *(struct sockaddr_in6 *)addr; + wg_socket_set_peer_endpoint(peer, &endpoint); + } + } + + if (flags & WGPEER_F_REPLACE_ALLOWEDIPS) + wg_allowedips_remove_by_peer(&wg->peer_allowedips, peer, + &wg->device_update_lock); + + if (attrs[WGPEER_A_ALLOWEDIPS]) { + struct nlattr *attr, *allowedip[WGALLOWEDIP_A_MAX + 1]; + int rem; + + nla_for_each_nested(attr, attrs[WGPEER_A_ALLOWEDIPS], rem) { + ret = nla_parse_nested(allowedip, WGALLOWEDIP_A_MAX, + attr, allowedip_policy, NULL); + if (ret < 0) + goto out; + ret = set_allowedip(peer, allowedip); + if (ret < 0) + goto out; + } + } + + if (attrs[WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL]) { + const u16 persistent_keepalive_interval = nla_get_u16( + attrs[WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL]); + const bool send_keepalive = + !peer->persistent_keepalive_interval && + persistent_keepalive_interval && + netif_running(wg->dev); + + peer->persistent_keepalive_interval = persistent_keepalive_interval; + if (send_keepalive) + wg_packet_send_keepalive(peer); + } + + if (netif_running(wg->dev)) + wg_packet_send_staged_packets(peer); + +out: + wg_peer_put(peer); + if (attrs[WGPEER_A_PRESHARED_KEY]) + memzero_explicit(nla_data(attrs[WGPEER_A_PRESHARED_KEY]), + nla_len(attrs[WGPEER_A_PRESHARED_KEY])); + return ret; +} + +static int wg_set_device(struct sk_buff *skb, struct genl_info *info) +{ + struct wg_device *wg = lookup_interface(info->attrs, skb); + u32 flags = 0; + int ret; + + if (IS_ERR(wg)) { + ret = PTR_ERR(wg); + goto out_nodev; + } + + rtnl_lock(); + mutex_lock(&wg->device_update_lock); + + if (info->attrs[WGDEVICE_A_FLAGS]) + flags = nla_get_u32(info->attrs[WGDEVICE_A_FLAGS]); + ret = -EOPNOTSUPP; + if (flags & ~__WGDEVICE_F_ALL) + goto out; + + if (info->attrs[WGDEVICE_A_LISTEN_PORT] || info->attrs[WGDEVICE_A_FWMARK]) { + struct net *net; + rcu_read_lock(); + net = rcu_dereference(wg->creating_net); + ret = !net || !ns_capable(net->user_ns, CAP_NET_ADMIN) ? -EPERM : 0; + rcu_read_unlock(); + if (ret) + goto out; + } + + ++wg->device_update_gen; + + if (info->attrs[WGDEVICE_A_FWMARK]) { + struct wg_peer *peer; + + wg->fwmark = nla_get_u32(info->attrs[WGDEVICE_A_FWMARK]); + list_for_each_entry(peer, &wg->peer_list, peer_list) + wg_socket_clear_peer_endpoint_src(peer); + } + + if (info->attrs[WGDEVICE_A_LISTEN_PORT]) { + ret = set_port(wg, + nla_get_u16(info->attrs[WGDEVICE_A_LISTEN_PORT])); + if (ret) + goto out; + } + + if (flags & WGDEVICE_F_REPLACE_PEERS) + wg_peer_remove_all(wg); + + if (info->attrs[WGDEVICE_A_PRIVATE_KEY] && + nla_len(info->attrs[WGDEVICE_A_PRIVATE_KEY]) == + NOISE_PUBLIC_KEY_LEN) { + u8 *private_key = nla_data(info->attrs[WGDEVICE_A_PRIVATE_KEY]); + u8 public_key[NOISE_PUBLIC_KEY_LEN]; + struct wg_peer *peer, *temp; + bool send_staged_packets; + + if (!crypto_memneq(wg->static_identity.static_private, + private_key, NOISE_PUBLIC_KEY_LEN)) + goto skip_set_private_key; + + /* We remove before setting, to prevent race, which means doing + * two 25519-genpub ops. + */ + if (curve25519_generate_public(public_key, private_key)) { + peer = wg_pubkey_hashtable_lookup(wg->peer_hashtable, + public_key); + if (peer) { + wg_peer_put(peer); + wg_peer_remove(peer); + } + } + + down_write(&wg->static_identity.lock); + send_staged_packets = !wg->static_identity.has_identity && netif_running(wg->dev); + wg_noise_set_static_identity_private_key(&wg->static_identity, private_key); + send_staged_packets = send_staged_packets && wg->static_identity.has_identity; + + wg_cookie_checker_precompute_device_keys(&wg->cookie_checker); + list_for_each_entry_safe(peer, temp, &wg->peer_list, peer_list) { + wg_noise_precompute_static_static(peer); + wg_noise_expire_current_peer_keypairs(peer); + if (send_staged_packets) + wg_packet_send_staged_packets(peer); + } + up_write(&wg->static_identity.lock); + } +skip_set_private_key: + + if (info->attrs[WGDEVICE_A_PEERS]) { + struct nlattr *attr, *peer[WGPEER_A_MAX + 1]; + int rem; + + nla_for_each_nested(attr, info->attrs[WGDEVICE_A_PEERS], rem) { + ret = nla_parse_nested(peer, WGPEER_A_MAX, attr, + peer_policy, NULL); + if (ret < 0) + goto out; + ret = set_peer(wg, peer); + if (ret < 0) + goto out; + } + } + ret = 0; + +out: + mutex_unlock(&wg->device_update_lock); + rtnl_unlock(); + dev_put(wg->dev); +out_nodev: + if (info->attrs[WGDEVICE_A_PRIVATE_KEY]) + memzero_explicit(nla_data(info->attrs[WGDEVICE_A_PRIVATE_KEY]), + nla_len(info->attrs[WGDEVICE_A_PRIVATE_KEY])); + return ret; +} + +static const struct genl_ops genl_ops[] = { + { + .cmd = WG_CMD_GET_DEVICE, + .start = wg_get_device_start, + .dumpit = wg_get_device_dump, + .done = wg_get_device_done, + .flags = GENL_UNS_ADMIN_PERM + }, { + .cmd = WG_CMD_SET_DEVICE, + .doit = wg_set_device, + .flags = GENL_UNS_ADMIN_PERM + } +}; + +static struct genl_family genl_family __ro_after_init = { + .ops = genl_ops, + .n_ops = ARRAY_SIZE(genl_ops), + .resv_start_op = WG_CMD_SET_DEVICE + 1, + .name = WG_GENL_NAME, + .version = WG_GENL_VERSION, + .maxattr = WGDEVICE_A_MAX, + .module = THIS_MODULE, + .policy = device_policy, + .netnsok = true +}; + +int __init wg_genetlink_init(void) +{ + return genl_register_family(&genl_family); +} + +void __exit wg_genetlink_uninit(void) +{ + genl_unregister_family(&genl_family); +} diff --git a/drivers/net/wireguard/netlink.h b/drivers/net/wireguard/netlink.h new file mode 100644 index 000000000..15100d92e --- /dev/null +++ b/drivers/net/wireguard/netlink.h @@ -0,0 +1,12 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#ifndef _WG_NETLINK_H +#define _WG_NETLINK_H + +int wg_genetlink_init(void); +void wg_genetlink_uninit(void); + +#endif /* _WG_NETLINK_H */ diff --git a/drivers/net/wireguard/noise.c b/drivers/net/wireguard/noise.c new file mode 100644 index 000000000..720952b92 --- /dev/null +++ b/drivers/net/wireguard/noise.c @@ -0,0 +1,861 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#include "noise.h" +#include "device.h" +#include "peer.h" +#include "messages.h" +#include "queueing.h" +#include "peerlookup.h" + +#include <linux/rcupdate.h> +#include <linux/slab.h> +#include <linux/bitmap.h> +#include <linux/scatterlist.h> +#include <linux/highmem.h> +#include <crypto/algapi.h> + +/* This implements Noise_IKpsk2: + * + * <- s + * ****** + * -> e, es, s, ss, {t} + * <- e, ee, se, psk, {} + */ + +static const u8 handshake_name[37] = "Noise_IKpsk2_25519_ChaChaPoly_BLAKE2s"; +static const u8 identifier_name[34] = "WireGuard v1 zx2c4 Jason@zx2c4.com"; +static u8 handshake_init_hash[NOISE_HASH_LEN] __ro_after_init; +static u8 handshake_init_chaining_key[NOISE_HASH_LEN] __ro_after_init; +static atomic64_t keypair_counter = ATOMIC64_INIT(0); + +void __init wg_noise_init(void) +{ + struct blake2s_state blake; + + blake2s(handshake_init_chaining_key, handshake_name, NULL, + NOISE_HASH_LEN, sizeof(handshake_name), 0); + blake2s_init(&blake, NOISE_HASH_LEN); + blake2s_update(&blake, handshake_init_chaining_key, NOISE_HASH_LEN); + blake2s_update(&blake, identifier_name, sizeof(identifier_name)); + blake2s_final(&blake, handshake_init_hash); +} + +/* Must hold peer->handshake.static_identity->lock */ +void wg_noise_precompute_static_static(struct wg_peer *peer) +{ + down_write(&peer->handshake.lock); + if (!peer->handshake.static_identity->has_identity || + !curve25519(peer->handshake.precomputed_static_static, + peer->handshake.static_identity->static_private, + peer->handshake.remote_static)) + memset(peer->handshake.precomputed_static_static, 0, + NOISE_PUBLIC_KEY_LEN); + up_write(&peer->handshake.lock); +} + +void wg_noise_handshake_init(struct noise_handshake *handshake, + struct noise_static_identity *static_identity, + const u8 peer_public_key[NOISE_PUBLIC_KEY_LEN], + const u8 peer_preshared_key[NOISE_SYMMETRIC_KEY_LEN], + struct wg_peer *peer) +{ + memset(handshake, 0, sizeof(*handshake)); + init_rwsem(&handshake->lock); + handshake->entry.type = INDEX_HASHTABLE_HANDSHAKE; + handshake->entry.peer = peer; + memcpy(handshake->remote_static, peer_public_key, NOISE_PUBLIC_KEY_LEN); + if (peer_preshared_key) + memcpy(handshake->preshared_key, peer_preshared_key, + NOISE_SYMMETRIC_KEY_LEN); + handshake->static_identity = static_identity; + handshake->state = HANDSHAKE_ZEROED; + wg_noise_precompute_static_static(peer); +} + +static void handshake_zero(struct noise_handshake *handshake) +{ + memset(&handshake->ephemeral_private, 0, NOISE_PUBLIC_KEY_LEN); + memset(&handshake->remote_ephemeral, 0, NOISE_PUBLIC_KEY_LEN); + memset(&handshake->hash, 0, NOISE_HASH_LEN); + memset(&handshake->chaining_key, 0, NOISE_HASH_LEN); + handshake->remote_index = 0; + handshake->state = HANDSHAKE_ZEROED; +} + +void wg_noise_handshake_clear(struct noise_handshake *handshake) +{ + down_write(&handshake->lock); + wg_index_hashtable_remove( + handshake->entry.peer->device->index_hashtable, + &handshake->entry); + handshake_zero(handshake); + up_write(&handshake->lock); +} + +static struct noise_keypair *keypair_create(struct wg_peer *peer) +{ + struct noise_keypair *keypair = kzalloc(sizeof(*keypair), GFP_KERNEL); + + if (unlikely(!keypair)) + return NULL; + spin_lock_init(&keypair->receiving_counter.lock); + keypair->internal_id = atomic64_inc_return(&keypair_counter); + keypair->entry.type = INDEX_HASHTABLE_KEYPAIR; + keypair->entry.peer = peer; + kref_init(&keypair->refcount); + return keypair; +} + +static void keypair_free_rcu(struct rcu_head *rcu) +{ + kfree_sensitive(container_of(rcu, struct noise_keypair, rcu)); +} + +static void keypair_free_kref(struct kref *kref) +{ + struct noise_keypair *keypair = + container_of(kref, struct noise_keypair, refcount); + + net_dbg_ratelimited("%s: Keypair %llu destroyed for peer %llu\n", + keypair->entry.peer->device->dev->name, + keypair->internal_id, + keypair->entry.peer->internal_id); + wg_index_hashtable_remove(keypair->entry.peer->device->index_hashtable, + &keypair->entry); + call_rcu(&keypair->rcu, keypair_free_rcu); +} + +void wg_noise_keypair_put(struct noise_keypair *keypair, bool unreference_now) +{ + if (unlikely(!keypair)) + return; + if (unlikely(unreference_now)) + wg_index_hashtable_remove( + keypair->entry.peer->device->index_hashtable, + &keypair->entry); + kref_put(&keypair->refcount, keypair_free_kref); +} + +struct noise_keypair *wg_noise_keypair_get(struct noise_keypair *keypair) +{ + RCU_LOCKDEP_WARN(!rcu_read_lock_bh_held(), + "Taking noise keypair reference without holding the RCU BH read lock"); + if (unlikely(!keypair || !kref_get_unless_zero(&keypair->refcount))) + return NULL; + return keypair; +} + +void wg_noise_keypairs_clear(struct noise_keypairs *keypairs) +{ + struct noise_keypair *old; + + spin_lock_bh(&keypairs->keypair_update_lock); + + /* We zero the next_keypair before zeroing the others, so that + * wg_noise_received_with_keypair returns early before subsequent ones + * are zeroed. + */ + old = rcu_dereference_protected(keypairs->next_keypair, + lockdep_is_held(&keypairs->keypair_update_lock)); + RCU_INIT_POINTER(keypairs->next_keypair, NULL); + wg_noise_keypair_put(old, true); + + old = rcu_dereference_protected(keypairs->previous_keypair, + lockdep_is_held(&keypairs->keypair_update_lock)); + RCU_INIT_POINTER(keypairs->previous_keypair, NULL); + wg_noise_keypair_put(old, true); + + old = rcu_dereference_protected(keypairs->current_keypair, + lockdep_is_held(&keypairs->keypair_update_lock)); + RCU_INIT_POINTER(keypairs->current_keypair, NULL); + wg_noise_keypair_put(old, true); + + spin_unlock_bh(&keypairs->keypair_update_lock); +} + +void wg_noise_expire_current_peer_keypairs(struct wg_peer *peer) +{ + struct noise_keypair *keypair; + + wg_noise_handshake_clear(&peer->handshake); + wg_noise_reset_last_sent_handshake(&peer->last_sent_handshake); + + spin_lock_bh(&peer->keypairs.keypair_update_lock); + keypair = rcu_dereference_protected(peer->keypairs.next_keypair, + lockdep_is_held(&peer->keypairs.keypair_update_lock)); + if (keypair) + keypair->sending.is_valid = false; + keypair = rcu_dereference_protected(peer->keypairs.current_keypair, + lockdep_is_held(&peer->keypairs.keypair_update_lock)); + if (keypair) + keypair->sending.is_valid = false; + spin_unlock_bh(&peer->keypairs.keypair_update_lock); +} + +static void add_new_keypair(struct noise_keypairs *keypairs, + struct noise_keypair *new_keypair) +{ + struct noise_keypair *previous_keypair, *next_keypair, *current_keypair; + + spin_lock_bh(&keypairs->keypair_update_lock); + previous_keypair = rcu_dereference_protected(keypairs->previous_keypair, + lockdep_is_held(&keypairs->keypair_update_lock)); + next_keypair = rcu_dereference_protected(keypairs->next_keypair, + lockdep_is_held(&keypairs->keypair_update_lock)); + current_keypair = rcu_dereference_protected(keypairs->current_keypair, + lockdep_is_held(&keypairs->keypair_update_lock)); + if (new_keypair->i_am_the_initiator) { + /* If we're the initiator, it means we've sent a handshake, and + * received a confirmation response, which means this new + * keypair can now be used. + */ + if (next_keypair) { + /* If there already was a next keypair pending, we + * demote it to be the previous keypair, and free the + * existing current. Note that this means KCI can result + * in this transition. It would perhaps be more sound to + * always just get rid of the unused next keypair + * instead of putting it in the previous slot, but this + * might be a bit less robust. Something to think about + * for the future. + */ + RCU_INIT_POINTER(keypairs->next_keypair, NULL); + rcu_assign_pointer(keypairs->previous_keypair, + next_keypair); + wg_noise_keypair_put(current_keypair, true); + } else /* If there wasn't an existing next keypair, we replace + * the previous with the current one. + */ + rcu_assign_pointer(keypairs->previous_keypair, + current_keypair); + /* At this point we can get rid of the old previous keypair, and + * set up the new keypair. + */ + wg_noise_keypair_put(previous_keypair, true); + rcu_assign_pointer(keypairs->current_keypair, new_keypair); + } else { + /* If we're the responder, it means we can't use the new keypair + * until we receive confirmation via the first data packet, so + * we get rid of the existing previous one, the possibly + * existing next one, and slide in the new next one. + */ + rcu_assign_pointer(keypairs->next_keypair, new_keypair); + wg_noise_keypair_put(next_keypair, true); + RCU_INIT_POINTER(keypairs->previous_keypair, NULL); + wg_noise_keypair_put(previous_keypair, true); + } + spin_unlock_bh(&keypairs->keypair_update_lock); +} + +bool wg_noise_received_with_keypair(struct noise_keypairs *keypairs, + struct noise_keypair *received_keypair) +{ + struct noise_keypair *old_keypair; + bool key_is_new; + + /* We first check without taking the spinlock. */ + key_is_new = received_keypair == + rcu_access_pointer(keypairs->next_keypair); + if (likely(!key_is_new)) + return false; + + spin_lock_bh(&keypairs->keypair_update_lock); + /* After locking, we double check that things didn't change from + * beneath us. + */ + if (unlikely(received_keypair != + rcu_dereference_protected(keypairs->next_keypair, + lockdep_is_held(&keypairs->keypair_update_lock)))) { + spin_unlock_bh(&keypairs->keypair_update_lock); + return false; + } + + /* When we've finally received the confirmation, we slide the next + * into the current, the current into the previous, and get rid of + * the old previous. + */ + old_keypair = rcu_dereference_protected(keypairs->previous_keypair, + lockdep_is_held(&keypairs->keypair_update_lock)); + rcu_assign_pointer(keypairs->previous_keypair, + rcu_dereference_protected(keypairs->current_keypair, + lockdep_is_held(&keypairs->keypair_update_lock))); + wg_noise_keypair_put(old_keypair, true); + rcu_assign_pointer(keypairs->current_keypair, received_keypair); + RCU_INIT_POINTER(keypairs->next_keypair, NULL); + + spin_unlock_bh(&keypairs->keypair_update_lock); + return true; +} + +/* Must hold static_identity->lock */ +void wg_noise_set_static_identity_private_key( + struct noise_static_identity *static_identity, + const u8 private_key[NOISE_PUBLIC_KEY_LEN]) +{ + memcpy(static_identity->static_private, private_key, + NOISE_PUBLIC_KEY_LEN); + curve25519_clamp_secret(static_identity->static_private); + static_identity->has_identity = curve25519_generate_public( + static_identity->static_public, private_key); +} + +static void hmac(u8 *out, const u8 *in, const u8 *key, const size_t inlen, const size_t keylen) +{ + struct blake2s_state state; + u8 x_key[BLAKE2S_BLOCK_SIZE] __aligned(__alignof__(u32)) = { 0 }; + u8 i_hash[BLAKE2S_HASH_SIZE] __aligned(__alignof__(u32)); + int i; + + if (keylen > BLAKE2S_BLOCK_SIZE) { + blake2s_init(&state, BLAKE2S_HASH_SIZE); + blake2s_update(&state, key, keylen); + blake2s_final(&state, x_key); + } else + memcpy(x_key, key, keylen); + + for (i = 0; i < BLAKE2S_BLOCK_SIZE; ++i) + x_key[i] ^= 0x36; + + blake2s_init(&state, BLAKE2S_HASH_SIZE); + blake2s_update(&state, x_key, BLAKE2S_BLOCK_SIZE); + blake2s_update(&state, in, inlen); + blake2s_final(&state, i_hash); + + for (i = 0; i < BLAKE2S_BLOCK_SIZE; ++i) + x_key[i] ^= 0x5c ^ 0x36; + + blake2s_init(&state, BLAKE2S_HASH_SIZE); + blake2s_update(&state, x_key, BLAKE2S_BLOCK_SIZE); + blake2s_update(&state, i_hash, BLAKE2S_HASH_SIZE); + blake2s_final(&state, i_hash); + + memcpy(out, i_hash, BLAKE2S_HASH_SIZE); + memzero_explicit(x_key, BLAKE2S_BLOCK_SIZE); + memzero_explicit(i_hash, BLAKE2S_HASH_SIZE); +} + +/* This is Hugo Krawczyk's HKDF: + * - https://eprint.iacr.org/2010/264.pdf + * - https://tools.ietf.org/html/rfc5869 + */ +static void kdf(u8 *first_dst, u8 *second_dst, u8 *third_dst, const u8 *data, + size_t first_len, size_t second_len, size_t third_len, + size_t data_len, const u8 chaining_key[NOISE_HASH_LEN]) +{ + u8 output[BLAKE2S_HASH_SIZE + 1]; + u8 secret[BLAKE2S_HASH_SIZE]; + + WARN_ON(IS_ENABLED(DEBUG) && + (first_len > BLAKE2S_HASH_SIZE || + second_len > BLAKE2S_HASH_SIZE || + third_len > BLAKE2S_HASH_SIZE || + ((second_len || second_dst || third_len || third_dst) && + (!first_len || !first_dst)) || + ((third_len || third_dst) && (!second_len || !second_dst)))); + + /* Extract entropy from data into secret */ + hmac(secret, data, chaining_key, data_len, NOISE_HASH_LEN); + + if (!first_dst || !first_len) + goto out; + + /* Expand first key: key = secret, data = 0x1 */ + output[0] = 1; + hmac(output, output, secret, 1, BLAKE2S_HASH_SIZE); + memcpy(first_dst, output, first_len); + + if (!second_dst || !second_len) + goto out; + + /* Expand second key: key = secret, data = first-key || 0x2 */ + output[BLAKE2S_HASH_SIZE] = 2; + hmac(output, output, secret, BLAKE2S_HASH_SIZE + 1, BLAKE2S_HASH_SIZE); + memcpy(second_dst, output, second_len); + + if (!third_dst || !third_len) + goto out; + + /* Expand third key: key = secret, data = second-key || 0x3 */ + output[BLAKE2S_HASH_SIZE] = 3; + hmac(output, output, secret, BLAKE2S_HASH_SIZE + 1, BLAKE2S_HASH_SIZE); + memcpy(third_dst, output, third_len); + +out: + /* Clear sensitive data from stack */ + memzero_explicit(secret, BLAKE2S_HASH_SIZE); + memzero_explicit(output, BLAKE2S_HASH_SIZE + 1); +} + +static void derive_keys(struct noise_symmetric_key *first_dst, + struct noise_symmetric_key *second_dst, + const u8 chaining_key[NOISE_HASH_LEN]) +{ + u64 birthdate = ktime_get_coarse_boottime_ns(); + kdf(first_dst->key, second_dst->key, NULL, NULL, + NOISE_SYMMETRIC_KEY_LEN, NOISE_SYMMETRIC_KEY_LEN, 0, 0, + chaining_key); + first_dst->birthdate = second_dst->birthdate = birthdate; + first_dst->is_valid = second_dst->is_valid = true; +} + +static bool __must_check mix_dh(u8 chaining_key[NOISE_HASH_LEN], + u8 key[NOISE_SYMMETRIC_KEY_LEN], + const u8 private[NOISE_PUBLIC_KEY_LEN], + const u8 public[NOISE_PUBLIC_KEY_LEN]) +{ + u8 dh_calculation[NOISE_PUBLIC_KEY_LEN]; + + if (unlikely(!curve25519(dh_calculation, private, public))) + return false; + kdf(chaining_key, key, NULL, dh_calculation, NOISE_HASH_LEN, + NOISE_SYMMETRIC_KEY_LEN, 0, NOISE_PUBLIC_KEY_LEN, chaining_key); + memzero_explicit(dh_calculation, NOISE_PUBLIC_KEY_LEN); + return true; +} + +static bool __must_check mix_precomputed_dh(u8 chaining_key[NOISE_HASH_LEN], + u8 key[NOISE_SYMMETRIC_KEY_LEN], + const u8 precomputed[NOISE_PUBLIC_KEY_LEN]) +{ + static u8 zero_point[NOISE_PUBLIC_KEY_LEN]; + if (unlikely(!crypto_memneq(precomputed, zero_point, NOISE_PUBLIC_KEY_LEN))) + return false; + kdf(chaining_key, key, NULL, precomputed, NOISE_HASH_LEN, + NOISE_SYMMETRIC_KEY_LEN, 0, NOISE_PUBLIC_KEY_LEN, + chaining_key); + return true; +} + +static void mix_hash(u8 hash[NOISE_HASH_LEN], const u8 *src, size_t src_len) +{ + struct blake2s_state blake; + + blake2s_init(&blake, NOISE_HASH_LEN); + blake2s_update(&blake, hash, NOISE_HASH_LEN); + blake2s_update(&blake, src, src_len); + blake2s_final(&blake, hash); +} + +static void mix_psk(u8 chaining_key[NOISE_HASH_LEN], u8 hash[NOISE_HASH_LEN], + u8 key[NOISE_SYMMETRIC_KEY_LEN], + const u8 psk[NOISE_SYMMETRIC_KEY_LEN]) +{ + u8 temp_hash[NOISE_HASH_LEN]; + + kdf(chaining_key, temp_hash, key, psk, NOISE_HASH_LEN, NOISE_HASH_LEN, + NOISE_SYMMETRIC_KEY_LEN, NOISE_SYMMETRIC_KEY_LEN, chaining_key); + mix_hash(hash, temp_hash, NOISE_HASH_LEN); + memzero_explicit(temp_hash, NOISE_HASH_LEN); +} + +static void handshake_init(u8 chaining_key[NOISE_HASH_LEN], + u8 hash[NOISE_HASH_LEN], + const u8 remote_static[NOISE_PUBLIC_KEY_LEN]) +{ + memcpy(hash, handshake_init_hash, NOISE_HASH_LEN); + memcpy(chaining_key, handshake_init_chaining_key, NOISE_HASH_LEN); + mix_hash(hash, remote_static, NOISE_PUBLIC_KEY_LEN); +} + +static void message_encrypt(u8 *dst_ciphertext, const u8 *src_plaintext, + size_t src_len, u8 key[NOISE_SYMMETRIC_KEY_LEN], + u8 hash[NOISE_HASH_LEN]) +{ + chacha20poly1305_encrypt(dst_ciphertext, src_plaintext, src_len, hash, + NOISE_HASH_LEN, + 0 /* Always zero for Noise_IK */, key); + mix_hash(hash, dst_ciphertext, noise_encrypted_len(src_len)); +} + +static bool message_decrypt(u8 *dst_plaintext, const u8 *src_ciphertext, + size_t src_len, u8 key[NOISE_SYMMETRIC_KEY_LEN], + u8 hash[NOISE_HASH_LEN]) +{ + if (!chacha20poly1305_decrypt(dst_plaintext, src_ciphertext, src_len, + hash, NOISE_HASH_LEN, + 0 /* Always zero for Noise_IK */, key)) + return false; + mix_hash(hash, src_ciphertext, src_len); + return true; +} + +static void message_ephemeral(u8 ephemeral_dst[NOISE_PUBLIC_KEY_LEN], + const u8 ephemeral_src[NOISE_PUBLIC_KEY_LEN], + u8 chaining_key[NOISE_HASH_LEN], + u8 hash[NOISE_HASH_LEN]) +{ + if (ephemeral_dst != ephemeral_src) + memcpy(ephemeral_dst, ephemeral_src, NOISE_PUBLIC_KEY_LEN); + mix_hash(hash, ephemeral_src, NOISE_PUBLIC_KEY_LEN); + kdf(chaining_key, NULL, NULL, ephemeral_src, NOISE_HASH_LEN, 0, 0, + NOISE_PUBLIC_KEY_LEN, chaining_key); +} + +static void tai64n_now(u8 output[NOISE_TIMESTAMP_LEN]) +{ + struct timespec64 now; + + ktime_get_real_ts64(&now); + + /* In order to prevent some sort of infoleak from precise timers, we + * round down the nanoseconds part to the closest rounded-down power of + * two to the maximum initiations per second allowed anyway by the + * implementation. + */ + now.tv_nsec = ALIGN_DOWN(now.tv_nsec, + rounddown_pow_of_two(NSEC_PER_SEC / INITIATIONS_PER_SECOND)); + + /* https://cr.yp.to/libtai/tai64.html */ + *(__be64 *)output = cpu_to_be64(0x400000000000000aULL + now.tv_sec); + *(__be32 *)(output + sizeof(__be64)) = cpu_to_be32(now.tv_nsec); +} + +bool +wg_noise_handshake_create_initiation(struct message_handshake_initiation *dst, + struct noise_handshake *handshake) +{ + u8 timestamp[NOISE_TIMESTAMP_LEN]; + u8 key[NOISE_SYMMETRIC_KEY_LEN]; + bool ret = false; + + /* We need to wait for crng _before_ taking any locks, since + * curve25519_generate_secret uses get_random_bytes_wait. + */ + wait_for_random_bytes(); + + down_read(&handshake->static_identity->lock); + down_write(&handshake->lock); + + if (unlikely(!handshake->static_identity->has_identity)) + goto out; + + dst->header.type = cpu_to_le32(MESSAGE_HANDSHAKE_INITIATION); + + handshake_init(handshake->chaining_key, handshake->hash, + handshake->remote_static); + + /* e */ + curve25519_generate_secret(handshake->ephemeral_private); + if (!curve25519_generate_public(dst->unencrypted_ephemeral, + handshake->ephemeral_private)) + goto out; + message_ephemeral(dst->unencrypted_ephemeral, + dst->unencrypted_ephemeral, handshake->chaining_key, + handshake->hash); + + /* es */ + if (!mix_dh(handshake->chaining_key, key, handshake->ephemeral_private, + handshake->remote_static)) + goto out; + + /* s */ + message_encrypt(dst->encrypted_static, + handshake->static_identity->static_public, + NOISE_PUBLIC_KEY_LEN, key, handshake->hash); + + /* ss */ + if (!mix_precomputed_dh(handshake->chaining_key, key, + handshake->precomputed_static_static)) + goto out; + + /* {t} */ + tai64n_now(timestamp); + message_encrypt(dst->encrypted_timestamp, timestamp, + NOISE_TIMESTAMP_LEN, key, handshake->hash); + + dst->sender_index = wg_index_hashtable_insert( + handshake->entry.peer->device->index_hashtable, + &handshake->entry); + + handshake->state = HANDSHAKE_CREATED_INITIATION; + ret = true; + +out: + up_write(&handshake->lock); + up_read(&handshake->static_identity->lock); + memzero_explicit(key, NOISE_SYMMETRIC_KEY_LEN); + return ret; +} + +struct wg_peer * +wg_noise_handshake_consume_initiation(struct message_handshake_initiation *src, + struct wg_device *wg) +{ + struct wg_peer *peer = NULL, *ret_peer = NULL; + struct noise_handshake *handshake; + bool replay_attack, flood_attack; + u8 key[NOISE_SYMMETRIC_KEY_LEN]; + u8 chaining_key[NOISE_HASH_LEN]; + u8 hash[NOISE_HASH_LEN]; + u8 s[NOISE_PUBLIC_KEY_LEN]; + u8 e[NOISE_PUBLIC_KEY_LEN]; + u8 t[NOISE_TIMESTAMP_LEN]; + u64 initiation_consumption; + + down_read(&wg->static_identity.lock); + if (unlikely(!wg->static_identity.has_identity)) + goto out; + + handshake_init(chaining_key, hash, wg->static_identity.static_public); + + /* e */ + message_ephemeral(e, src->unencrypted_ephemeral, chaining_key, hash); + + /* es */ + if (!mix_dh(chaining_key, key, wg->static_identity.static_private, e)) + goto out; + + /* s */ + if (!message_decrypt(s, src->encrypted_static, + sizeof(src->encrypted_static), key, hash)) + goto out; + + /* Lookup which peer we're actually talking to */ + peer = wg_pubkey_hashtable_lookup(wg->peer_hashtable, s); + if (!peer) + goto out; + handshake = &peer->handshake; + + /* ss */ + if (!mix_precomputed_dh(chaining_key, key, + handshake->precomputed_static_static)) + goto out; + + /* {t} */ + if (!message_decrypt(t, src->encrypted_timestamp, + sizeof(src->encrypted_timestamp), key, hash)) + goto out; + + down_read(&handshake->lock); + replay_attack = memcmp(t, handshake->latest_timestamp, + NOISE_TIMESTAMP_LEN) <= 0; + flood_attack = (s64)handshake->last_initiation_consumption + + NSEC_PER_SEC / INITIATIONS_PER_SECOND > + (s64)ktime_get_coarse_boottime_ns(); + up_read(&handshake->lock); + if (replay_attack || flood_attack) + goto out; + + /* Success! Copy everything to peer */ + down_write(&handshake->lock); + memcpy(handshake->remote_ephemeral, e, NOISE_PUBLIC_KEY_LEN); + if (memcmp(t, handshake->latest_timestamp, NOISE_TIMESTAMP_LEN) > 0) + memcpy(handshake->latest_timestamp, t, NOISE_TIMESTAMP_LEN); + memcpy(handshake->hash, hash, NOISE_HASH_LEN); + memcpy(handshake->chaining_key, chaining_key, NOISE_HASH_LEN); + handshake->remote_index = src->sender_index; + initiation_consumption = ktime_get_coarse_boottime_ns(); + if ((s64)(handshake->last_initiation_consumption - initiation_consumption) < 0) + handshake->last_initiation_consumption = initiation_consumption; + handshake->state = HANDSHAKE_CONSUMED_INITIATION; + up_write(&handshake->lock); + ret_peer = peer; + +out: + memzero_explicit(key, NOISE_SYMMETRIC_KEY_LEN); + memzero_explicit(hash, NOISE_HASH_LEN); + memzero_explicit(chaining_key, NOISE_HASH_LEN); + up_read(&wg->static_identity.lock); + if (!ret_peer) + wg_peer_put(peer); + return ret_peer; +} + +bool wg_noise_handshake_create_response(struct message_handshake_response *dst, + struct noise_handshake *handshake) +{ + u8 key[NOISE_SYMMETRIC_KEY_LEN]; + bool ret = false; + + /* We need to wait for crng _before_ taking any locks, since + * curve25519_generate_secret uses get_random_bytes_wait. + */ + wait_for_random_bytes(); + + down_read(&handshake->static_identity->lock); + down_write(&handshake->lock); + + if (handshake->state != HANDSHAKE_CONSUMED_INITIATION) + goto out; + + dst->header.type = cpu_to_le32(MESSAGE_HANDSHAKE_RESPONSE); + dst->receiver_index = handshake->remote_index; + + /* e */ + curve25519_generate_secret(handshake->ephemeral_private); + if (!curve25519_generate_public(dst->unencrypted_ephemeral, + handshake->ephemeral_private)) + goto out; + message_ephemeral(dst->unencrypted_ephemeral, + dst->unencrypted_ephemeral, handshake->chaining_key, + handshake->hash); + + /* ee */ + if (!mix_dh(handshake->chaining_key, NULL, handshake->ephemeral_private, + handshake->remote_ephemeral)) + goto out; + + /* se */ + if (!mix_dh(handshake->chaining_key, NULL, handshake->ephemeral_private, + handshake->remote_static)) + goto out; + + /* psk */ + mix_psk(handshake->chaining_key, handshake->hash, key, + handshake->preshared_key); + + /* {} */ + message_encrypt(dst->encrypted_nothing, NULL, 0, key, handshake->hash); + + dst->sender_index = wg_index_hashtable_insert( + handshake->entry.peer->device->index_hashtable, + &handshake->entry); + + handshake->state = HANDSHAKE_CREATED_RESPONSE; + ret = true; + +out: + up_write(&handshake->lock); + up_read(&handshake->static_identity->lock); + memzero_explicit(key, NOISE_SYMMETRIC_KEY_LEN); + return ret; +} + +struct wg_peer * +wg_noise_handshake_consume_response(struct message_handshake_response *src, + struct wg_device *wg) +{ + enum noise_handshake_state state = HANDSHAKE_ZEROED; + struct wg_peer *peer = NULL, *ret_peer = NULL; + struct noise_handshake *handshake; + u8 key[NOISE_SYMMETRIC_KEY_LEN]; + u8 hash[NOISE_HASH_LEN]; + u8 chaining_key[NOISE_HASH_LEN]; + u8 e[NOISE_PUBLIC_KEY_LEN]; + u8 ephemeral_private[NOISE_PUBLIC_KEY_LEN]; + u8 static_private[NOISE_PUBLIC_KEY_LEN]; + u8 preshared_key[NOISE_SYMMETRIC_KEY_LEN]; + + down_read(&wg->static_identity.lock); + + if (unlikely(!wg->static_identity.has_identity)) + goto out; + + handshake = (struct noise_handshake *)wg_index_hashtable_lookup( + wg->index_hashtable, INDEX_HASHTABLE_HANDSHAKE, + src->receiver_index, &peer); + if (unlikely(!handshake)) + goto out; + + down_read(&handshake->lock); + state = handshake->state; + memcpy(hash, handshake->hash, NOISE_HASH_LEN); + memcpy(chaining_key, handshake->chaining_key, NOISE_HASH_LEN); + memcpy(ephemeral_private, handshake->ephemeral_private, + NOISE_PUBLIC_KEY_LEN); + memcpy(preshared_key, handshake->preshared_key, + NOISE_SYMMETRIC_KEY_LEN); + up_read(&handshake->lock); + + if (state != HANDSHAKE_CREATED_INITIATION) + goto fail; + + /* e */ + message_ephemeral(e, src->unencrypted_ephemeral, chaining_key, hash); + + /* ee */ + if (!mix_dh(chaining_key, NULL, ephemeral_private, e)) + goto fail; + + /* se */ + if (!mix_dh(chaining_key, NULL, wg->static_identity.static_private, e)) + goto fail; + + /* psk */ + mix_psk(chaining_key, hash, key, preshared_key); + + /* {} */ + if (!message_decrypt(NULL, src->encrypted_nothing, + sizeof(src->encrypted_nothing), key, hash)) + goto fail; + + /* Success! Copy everything to peer */ + down_write(&handshake->lock); + /* It's important to check that the state is still the same, while we + * have an exclusive lock. + */ + if (handshake->state != state) { + up_write(&handshake->lock); + goto fail; + } + memcpy(handshake->remote_ephemeral, e, NOISE_PUBLIC_KEY_LEN); + memcpy(handshake->hash, hash, NOISE_HASH_LEN); + memcpy(handshake->chaining_key, chaining_key, NOISE_HASH_LEN); + handshake->remote_index = src->sender_index; + handshake->state = HANDSHAKE_CONSUMED_RESPONSE; + up_write(&handshake->lock); + ret_peer = peer; + goto out; + +fail: + wg_peer_put(peer); +out: + memzero_explicit(key, NOISE_SYMMETRIC_KEY_LEN); + memzero_explicit(hash, NOISE_HASH_LEN); + memzero_explicit(chaining_key, NOISE_HASH_LEN); + memzero_explicit(ephemeral_private, NOISE_PUBLIC_KEY_LEN); + memzero_explicit(static_private, NOISE_PUBLIC_KEY_LEN); + memzero_explicit(preshared_key, NOISE_SYMMETRIC_KEY_LEN); + up_read(&wg->static_identity.lock); + return ret_peer; +} + +bool wg_noise_handshake_begin_session(struct noise_handshake *handshake, + struct noise_keypairs *keypairs) +{ + struct noise_keypair *new_keypair; + bool ret = false; + + down_write(&handshake->lock); + if (handshake->state != HANDSHAKE_CREATED_RESPONSE && + handshake->state != HANDSHAKE_CONSUMED_RESPONSE) + goto out; + + new_keypair = keypair_create(handshake->entry.peer); + if (!new_keypair) + goto out; + new_keypair->i_am_the_initiator = handshake->state == + HANDSHAKE_CONSUMED_RESPONSE; + new_keypair->remote_index = handshake->remote_index; + + if (new_keypair->i_am_the_initiator) + derive_keys(&new_keypair->sending, &new_keypair->receiving, + handshake->chaining_key); + else + derive_keys(&new_keypair->receiving, &new_keypair->sending, + handshake->chaining_key); + + handshake_zero(handshake); + rcu_read_lock_bh(); + if (likely(!READ_ONCE(container_of(handshake, struct wg_peer, + handshake)->is_dead))) { + add_new_keypair(keypairs, new_keypair); + net_dbg_ratelimited("%s: Keypair %llu created for peer %llu\n", + handshake->entry.peer->device->dev->name, + new_keypair->internal_id, + handshake->entry.peer->internal_id); + ret = wg_index_hashtable_replace( + handshake->entry.peer->device->index_hashtable, + &handshake->entry, &new_keypair->entry); + } else { + kfree_sensitive(new_keypair); + } + rcu_read_unlock_bh(); + +out: + up_write(&handshake->lock); + return ret; +} diff --git a/drivers/net/wireguard/noise.h b/drivers/net/wireguard/noise.h new file mode 100644 index 000000000..c527253db --- /dev/null +++ b/drivers/net/wireguard/noise.h @@ -0,0 +1,135 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ +#ifndef _WG_NOISE_H +#define _WG_NOISE_H + +#include "messages.h" +#include "peerlookup.h" + +#include <linux/types.h> +#include <linux/spinlock.h> +#include <linux/atomic.h> +#include <linux/rwsem.h> +#include <linux/mutex.h> +#include <linux/kref.h> + +struct noise_replay_counter { + u64 counter; + spinlock_t lock; + unsigned long backtrack[COUNTER_BITS_TOTAL / BITS_PER_LONG]; +}; + +struct noise_symmetric_key { + u8 key[NOISE_SYMMETRIC_KEY_LEN]; + u64 birthdate; + bool is_valid; +}; + +struct noise_keypair { + struct index_hashtable_entry entry; + struct noise_symmetric_key sending; + atomic64_t sending_counter; + struct noise_symmetric_key receiving; + struct noise_replay_counter receiving_counter; + __le32 remote_index; + bool i_am_the_initiator; + struct kref refcount; + struct rcu_head rcu; + u64 internal_id; +}; + +struct noise_keypairs { + struct noise_keypair __rcu *current_keypair; + struct noise_keypair __rcu *previous_keypair; + struct noise_keypair __rcu *next_keypair; + spinlock_t keypair_update_lock; +}; + +struct noise_static_identity { + u8 static_public[NOISE_PUBLIC_KEY_LEN]; + u8 static_private[NOISE_PUBLIC_KEY_LEN]; + struct rw_semaphore lock; + bool has_identity; +}; + +enum noise_handshake_state { + HANDSHAKE_ZEROED, + HANDSHAKE_CREATED_INITIATION, + HANDSHAKE_CONSUMED_INITIATION, + HANDSHAKE_CREATED_RESPONSE, + HANDSHAKE_CONSUMED_RESPONSE +}; + +struct noise_handshake { + struct index_hashtable_entry entry; + + enum noise_handshake_state state; + u64 last_initiation_consumption; + + struct noise_static_identity *static_identity; + + u8 ephemeral_private[NOISE_PUBLIC_KEY_LEN]; + u8 remote_static[NOISE_PUBLIC_KEY_LEN]; + u8 remote_ephemeral[NOISE_PUBLIC_KEY_LEN]; + u8 precomputed_static_static[NOISE_PUBLIC_KEY_LEN]; + + u8 preshared_key[NOISE_SYMMETRIC_KEY_LEN]; + + u8 hash[NOISE_HASH_LEN]; + u8 chaining_key[NOISE_HASH_LEN]; + + u8 latest_timestamp[NOISE_TIMESTAMP_LEN]; + __le32 remote_index; + + /* Protects all members except the immutable (after noise_handshake_ + * init): remote_static, precomputed_static_static, static_identity. + */ + struct rw_semaphore lock; +}; + +struct wg_device; + +void wg_noise_init(void); +void wg_noise_handshake_init(struct noise_handshake *handshake, + struct noise_static_identity *static_identity, + const u8 peer_public_key[NOISE_PUBLIC_KEY_LEN], + const u8 peer_preshared_key[NOISE_SYMMETRIC_KEY_LEN], + struct wg_peer *peer); +void wg_noise_handshake_clear(struct noise_handshake *handshake); +static inline void wg_noise_reset_last_sent_handshake(atomic64_t *handshake_ns) +{ + atomic64_set(handshake_ns, ktime_get_coarse_boottime_ns() - + (u64)(REKEY_TIMEOUT + 1) * NSEC_PER_SEC); +} + +void wg_noise_keypair_put(struct noise_keypair *keypair, bool unreference_now); +struct noise_keypair *wg_noise_keypair_get(struct noise_keypair *keypair); +void wg_noise_keypairs_clear(struct noise_keypairs *keypairs); +bool wg_noise_received_with_keypair(struct noise_keypairs *keypairs, + struct noise_keypair *received_keypair); +void wg_noise_expire_current_peer_keypairs(struct wg_peer *peer); + +void wg_noise_set_static_identity_private_key( + struct noise_static_identity *static_identity, + const u8 private_key[NOISE_PUBLIC_KEY_LEN]); +void wg_noise_precompute_static_static(struct wg_peer *peer); + +bool +wg_noise_handshake_create_initiation(struct message_handshake_initiation *dst, + struct noise_handshake *handshake); +struct wg_peer * +wg_noise_handshake_consume_initiation(struct message_handshake_initiation *src, + struct wg_device *wg); + +bool wg_noise_handshake_create_response(struct message_handshake_response *dst, + struct noise_handshake *handshake); +struct wg_peer * +wg_noise_handshake_consume_response(struct message_handshake_response *src, + struct wg_device *wg); + +bool wg_noise_handshake_begin_session(struct noise_handshake *handshake, + struct noise_keypairs *keypairs); + +#endif /* _WG_NOISE_H */ diff --git a/drivers/net/wireguard/peer.c b/drivers/net/wireguard/peer.c new file mode 100644 index 000000000..1cb502a93 --- /dev/null +++ b/drivers/net/wireguard/peer.c @@ -0,0 +1,239 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#include "peer.h" +#include "device.h" +#include "queueing.h" +#include "timers.h" +#include "peerlookup.h" +#include "noise.h" + +#include <linux/kref.h> +#include <linux/lockdep.h> +#include <linux/rcupdate.h> +#include <linux/list.h> + +static struct kmem_cache *peer_cache; +static atomic64_t peer_counter = ATOMIC64_INIT(0); + +struct wg_peer *wg_peer_create(struct wg_device *wg, + const u8 public_key[NOISE_PUBLIC_KEY_LEN], + const u8 preshared_key[NOISE_SYMMETRIC_KEY_LEN]) +{ + struct wg_peer *peer; + int ret = -ENOMEM; + + lockdep_assert_held(&wg->device_update_lock); + + if (wg->num_peers >= MAX_PEERS_PER_DEVICE) + return ERR_PTR(ret); + + peer = kmem_cache_zalloc(peer_cache, GFP_KERNEL); + if (unlikely(!peer)) + return ERR_PTR(ret); + if (unlikely(dst_cache_init(&peer->endpoint_cache, GFP_KERNEL))) + goto err; + + peer->device = wg; + wg_noise_handshake_init(&peer->handshake, &wg->static_identity, + public_key, preshared_key, peer); + peer->internal_id = atomic64_inc_return(&peer_counter); + peer->serial_work_cpu = nr_cpumask_bits; + wg_cookie_init(&peer->latest_cookie); + wg_timers_init(peer); + wg_cookie_checker_precompute_peer_keys(peer); + spin_lock_init(&peer->keypairs.keypair_update_lock); + INIT_WORK(&peer->transmit_handshake_work, wg_packet_handshake_send_worker); + INIT_WORK(&peer->transmit_packet_work, wg_packet_tx_worker); + wg_prev_queue_init(&peer->tx_queue); + wg_prev_queue_init(&peer->rx_queue); + rwlock_init(&peer->endpoint_lock); + kref_init(&peer->refcount); + skb_queue_head_init(&peer->staged_packet_queue); + wg_noise_reset_last_sent_handshake(&peer->last_sent_handshake); + set_bit(NAPI_STATE_NO_BUSY_POLL, &peer->napi.state); + netif_napi_add(wg->dev, &peer->napi, wg_packet_rx_poll); + napi_enable(&peer->napi); + list_add_tail(&peer->peer_list, &wg->peer_list); + INIT_LIST_HEAD(&peer->allowedips_list); + wg_pubkey_hashtable_add(wg->peer_hashtable, peer); + ++wg->num_peers; + pr_debug("%s: Peer %llu created\n", wg->dev->name, peer->internal_id); + return peer; + +err: + kmem_cache_free(peer_cache, peer); + return ERR_PTR(ret); +} + +struct wg_peer *wg_peer_get_maybe_zero(struct wg_peer *peer) +{ + RCU_LOCKDEP_WARN(!rcu_read_lock_bh_held(), + "Taking peer reference without holding the RCU read lock"); + if (unlikely(!peer || !kref_get_unless_zero(&peer->refcount))) + return NULL; + return peer; +} + +static void peer_make_dead(struct wg_peer *peer) +{ + /* Remove from configuration-time lookup structures. */ + list_del_init(&peer->peer_list); + wg_allowedips_remove_by_peer(&peer->device->peer_allowedips, peer, + &peer->device->device_update_lock); + wg_pubkey_hashtable_remove(peer->device->peer_hashtable, peer); + + /* Mark as dead, so that we don't allow jumping contexts after. */ + WRITE_ONCE(peer->is_dead, true); + + /* The caller must now synchronize_net() for this to take effect. */ +} + +static void peer_remove_after_dead(struct wg_peer *peer) +{ + WARN_ON(!peer->is_dead); + + /* No more keypairs can be created for this peer, since is_dead protects + * add_new_keypair, so we can now destroy existing ones. + */ + wg_noise_keypairs_clear(&peer->keypairs); + + /* Destroy all ongoing timers that were in-flight at the beginning of + * this function. + */ + wg_timers_stop(peer); + + /* The transition between packet encryption/decryption queues isn't + * guarded by is_dead, but each reference's life is strictly bounded by + * two generations: once for parallel crypto and once for serial + * ingestion, so we can simply flush twice, and be sure that we no + * longer have references inside these queues. + */ + + /* a) For encrypt/decrypt. */ + flush_workqueue(peer->device->packet_crypt_wq); + /* b.1) For send (but not receive, since that's napi). */ + flush_workqueue(peer->device->packet_crypt_wq); + /* b.2.1) For receive (but not send, since that's wq). */ + napi_disable(&peer->napi); + /* b.2.1) It's now safe to remove the napi struct, which must be done + * here from process context. + */ + netif_napi_del(&peer->napi); + + /* Ensure any workstructs we own (like transmit_handshake_work or + * clear_peer_work) no longer are in use. + */ + flush_workqueue(peer->device->handshake_send_wq); + + /* After the above flushes, a peer might still be active in a few + * different contexts: 1) from xmit(), before hitting is_dead and + * returning, 2) from wg_packet_consume_data(), before hitting is_dead + * and returning, 3) from wg_receive_handshake_packet() after a point + * where it has processed an incoming handshake packet, but where + * all calls to pass it off to timers fails because of is_dead. We won't + * have new references in (1) eventually, because we're removed from + * allowedips; we won't have new references in (2) eventually, because + * wg_index_hashtable_lookup will always return NULL, since we removed + * all existing keypairs and no more can be created; we won't have new + * references in (3) eventually, because we're removed from the pubkey + * hash table, which allows for a maximum of one handshake response, + * via the still-uncleared index hashtable entry, but not more than one, + * and in wg_cookie_message_consume, the lookup eventually gets a peer + * with a refcount of zero, so no new reference is taken. + */ + + --peer->device->num_peers; + wg_peer_put(peer); +} + +/* We have a separate "remove" function make sure that all active places where + * a peer is currently operating will eventually come to an end and not pass + * their reference onto another context. + */ +void wg_peer_remove(struct wg_peer *peer) +{ + if (unlikely(!peer)) + return; + lockdep_assert_held(&peer->device->device_update_lock); + + peer_make_dead(peer); + synchronize_net(); + peer_remove_after_dead(peer); +} + +void wg_peer_remove_all(struct wg_device *wg) +{ + struct wg_peer *peer, *temp; + LIST_HEAD(dead_peers); + + lockdep_assert_held(&wg->device_update_lock); + + /* Avoid having to traverse individually for each one. */ + wg_allowedips_free(&wg->peer_allowedips, &wg->device_update_lock); + + list_for_each_entry_safe(peer, temp, &wg->peer_list, peer_list) { + peer_make_dead(peer); + list_add_tail(&peer->peer_list, &dead_peers); + } + synchronize_net(); + list_for_each_entry_safe(peer, temp, &dead_peers, peer_list) + peer_remove_after_dead(peer); +} + +static void rcu_release(struct rcu_head *rcu) +{ + struct wg_peer *peer = container_of(rcu, struct wg_peer, rcu); + + dst_cache_destroy(&peer->endpoint_cache); + WARN_ON(wg_prev_queue_peek(&peer->tx_queue) || wg_prev_queue_peek(&peer->rx_queue)); + + /* The final zeroing takes care of clearing any remaining handshake key + * material and other potentially sensitive information. + */ + memzero_explicit(peer, sizeof(*peer)); + kmem_cache_free(peer_cache, peer); +} + +static void kref_release(struct kref *refcount) +{ + struct wg_peer *peer = container_of(refcount, struct wg_peer, refcount); + + pr_debug("%s: Peer %llu (%pISpfsc) destroyed\n", + peer->device->dev->name, peer->internal_id, + &peer->endpoint.addr); + + /* Remove ourself from dynamic runtime lookup structures, now that the + * last reference is gone. + */ + wg_index_hashtable_remove(peer->device->index_hashtable, + &peer->handshake.entry); + + /* Remove any lingering packets that didn't have a chance to be + * transmitted. + */ + wg_packet_purge_staged_packets(peer); + + /* Free the memory used. */ + call_rcu(&peer->rcu, rcu_release); +} + +void wg_peer_put(struct wg_peer *peer) +{ + if (unlikely(!peer)) + return; + kref_put(&peer->refcount, kref_release); +} + +int __init wg_peer_init(void) +{ + peer_cache = KMEM_CACHE(wg_peer, 0); + return peer_cache ? 0 : -ENOMEM; +} + +void wg_peer_uninit(void) +{ + kmem_cache_destroy(peer_cache); +} diff --git a/drivers/net/wireguard/peer.h b/drivers/net/wireguard/peer.h new file mode 100644 index 000000000..76e4d3128 --- /dev/null +++ b/drivers/net/wireguard/peer.h @@ -0,0 +1,86 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#ifndef _WG_PEER_H +#define _WG_PEER_H + +#include "device.h" +#include "noise.h" +#include "cookie.h" + +#include <linux/types.h> +#include <linux/netfilter.h> +#include <linux/spinlock.h> +#include <linux/kref.h> +#include <net/dst_cache.h> + +struct wg_device; + +struct endpoint { + union { + struct sockaddr addr; + struct sockaddr_in addr4; + struct sockaddr_in6 addr6; + }; + union { + struct { + struct in_addr src4; + /* Essentially the same as addr6->scope_id */ + int src_if4; + }; + struct in6_addr src6; + }; +}; + +struct wg_peer { + struct wg_device *device; + struct prev_queue tx_queue, rx_queue; + struct sk_buff_head staged_packet_queue; + int serial_work_cpu; + bool is_dead; + struct noise_keypairs keypairs; + struct endpoint endpoint; + struct dst_cache endpoint_cache; + rwlock_t endpoint_lock; + struct noise_handshake handshake; + atomic64_t last_sent_handshake; + struct work_struct transmit_handshake_work, clear_peer_work, transmit_packet_work; + struct cookie latest_cookie; + struct hlist_node pubkey_hash; + u64 rx_bytes, tx_bytes; + struct timer_list timer_retransmit_handshake, timer_send_keepalive; + struct timer_list timer_new_handshake, timer_zero_key_material; + struct timer_list timer_persistent_keepalive; + unsigned int timer_handshake_attempts; + u16 persistent_keepalive_interval; + bool timer_need_another_keepalive; + bool sent_lastminute_handshake; + struct timespec64 walltime_last_handshake; + struct kref refcount; + struct rcu_head rcu; + struct list_head peer_list; + struct list_head allowedips_list; + struct napi_struct napi; + u64 internal_id; +}; + +struct wg_peer *wg_peer_create(struct wg_device *wg, + const u8 public_key[NOISE_PUBLIC_KEY_LEN], + const u8 preshared_key[NOISE_SYMMETRIC_KEY_LEN]); + +struct wg_peer *__must_check wg_peer_get_maybe_zero(struct wg_peer *peer); +static inline struct wg_peer *wg_peer_get(struct wg_peer *peer) +{ + kref_get(&peer->refcount); + return peer; +} +void wg_peer_put(struct wg_peer *peer); +void wg_peer_remove(struct wg_peer *peer); +void wg_peer_remove_all(struct wg_device *wg); + +int wg_peer_init(void); +void wg_peer_uninit(void); + +#endif /* _WG_PEER_H */ diff --git a/drivers/net/wireguard/peerlookup.c b/drivers/net/wireguard/peerlookup.c new file mode 100644 index 000000000..f2783aa7a --- /dev/null +++ b/drivers/net/wireguard/peerlookup.c @@ -0,0 +1,226 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#include "peerlookup.h" +#include "peer.h" +#include "noise.h" + +static struct hlist_head *pubkey_bucket(struct pubkey_hashtable *table, + const u8 pubkey[NOISE_PUBLIC_KEY_LEN]) +{ + /* siphash gives us a secure 64bit number based on a random key. Since + * the bits are uniformly distributed, we can then mask off to get the + * bits we need. + */ + const u64 hash = siphash(pubkey, NOISE_PUBLIC_KEY_LEN, &table->key); + + return &table->hashtable[hash & (HASH_SIZE(table->hashtable) - 1)]; +} + +struct pubkey_hashtable *wg_pubkey_hashtable_alloc(void) +{ + struct pubkey_hashtable *table = kvmalloc(sizeof(*table), GFP_KERNEL); + + if (!table) + return NULL; + + get_random_bytes(&table->key, sizeof(table->key)); + hash_init(table->hashtable); + mutex_init(&table->lock); + return table; +} + +void wg_pubkey_hashtable_add(struct pubkey_hashtable *table, + struct wg_peer *peer) +{ + mutex_lock(&table->lock); + hlist_add_head_rcu(&peer->pubkey_hash, + pubkey_bucket(table, peer->handshake.remote_static)); + mutex_unlock(&table->lock); +} + +void wg_pubkey_hashtable_remove(struct pubkey_hashtable *table, + struct wg_peer *peer) +{ + mutex_lock(&table->lock); + hlist_del_init_rcu(&peer->pubkey_hash); + mutex_unlock(&table->lock); +} + +/* Returns a strong reference to a peer */ +struct wg_peer * +wg_pubkey_hashtable_lookup(struct pubkey_hashtable *table, + const u8 pubkey[NOISE_PUBLIC_KEY_LEN]) +{ + struct wg_peer *iter_peer, *peer = NULL; + + rcu_read_lock_bh(); + hlist_for_each_entry_rcu_bh(iter_peer, pubkey_bucket(table, pubkey), + pubkey_hash) { + if (!memcmp(pubkey, iter_peer->handshake.remote_static, + NOISE_PUBLIC_KEY_LEN)) { + peer = iter_peer; + break; + } + } + peer = wg_peer_get_maybe_zero(peer); + rcu_read_unlock_bh(); + return peer; +} + +static struct hlist_head *index_bucket(struct index_hashtable *table, + const __le32 index) +{ + /* Since the indices are random and thus all bits are uniformly + * distributed, we can find its bucket simply by masking. + */ + return &table->hashtable[(__force u32)index & + (HASH_SIZE(table->hashtable) - 1)]; +} + +struct index_hashtable *wg_index_hashtable_alloc(void) +{ + struct index_hashtable *table = kvmalloc(sizeof(*table), GFP_KERNEL); + + if (!table) + return NULL; + + hash_init(table->hashtable); + spin_lock_init(&table->lock); + return table; +} + +/* At the moment, we limit ourselves to 2^20 total peers, which generally might + * amount to 2^20*3 items in this hashtable. The algorithm below works by + * picking a random number and testing it. We can see that these limits mean we + * usually succeed pretty quickly: + * + * >>> def calculation(tries, size): + * ... return (size / 2**32)**(tries - 1) * (1 - (size / 2**32)) + * ... + * >>> calculation(1, 2**20 * 3) + * 0.999267578125 + * >>> calculation(2, 2**20 * 3) + * 0.0007318854331970215 + * >>> calculation(3, 2**20 * 3) + * 5.360489012673497e-07 + * >>> calculation(4, 2**20 * 3) + * 3.9261394135792216e-10 + * + * At the moment, we don't do any masking, so this algorithm isn't exactly + * constant time in either the random guessing or in the hash list lookup. We + * could require a minimum of 3 tries, which would successfully mask the + * guessing. this would not, however, help with the growing hash lengths, which + * is another thing to consider moving forward. + */ + +__le32 wg_index_hashtable_insert(struct index_hashtable *table, + struct index_hashtable_entry *entry) +{ + struct index_hashtable_entry *existing_entry; + + spin_lock_bh(&table->lock); + hlist_del_init_rcu(&entry->index_hash); + spin_unlock_bh(&table->lock); + + rcu_read_lock_bh(); + +search_unused_slot: + /* First we try to find an unused slot, randomly, while unlocked. */ + entry->index = (__force __le32)get_random_u32(); + hlist_for_each_entry_rcu_bh(existing_entry, + index_bucket(table, entry->index), + index_hash) { + if (existing_entry->index == entry->index) + /* If it's already in use, we continue searching. */ + goto search_unused_slot; + } + + /* Once we've found an unused slot, we lock it, and then double-check + * that nobody else stole it from us. + */ + spin_lock_bh(&table->lock); + hlist_for_each_entry_rcu_bh(existing_entry, + index_bucket(table, entry->index), + index_hash) { + if (existing_entry->index == entry->index) { + spin_unlock_bh(&table->lock); + /* If it was stolen, we start over. */ + goto search_unused_slot; + } + } + /* Otherwise, we know we have it exclusively (since we're locked), + * so we insert. + */ + hlist_add_head_rcu(&entry->index_hash, + index_bucket(table, entry->index)); + spin_unlock_bh(&table->lock); + + rcu_read_unlock_bh(); + + return entry->index; +} + +bool wg_index_hashtable_replace(struct index_hashtable *table, + struct index_hashtable_entry *old, + struct index_hashtable_entry *new) +{ + bool ret; + + spin_lock_bh(&table->lock); + ret = !hlist_unhashed(&old->index_hash); + if (unlikely(!ret)) + goto out; + + new->index = old->index; + hlist_replace_rcu(&old->index_hash, &new->index_hash); + + /* Calling init here NULLs out index_hash, and in fact after this + * function returns, it's theoretically possible for this to get + * reinserted elsewhere. That means the RCU lookup below might either + * terminate early or jump between buckets, in which case the packet + * simply gets dropped, which isn't terrible. + */ + INIT_HLIST_NODE(&old->index_hash); +out: + spin_unlock_bh(&table->lock); + return ret; +} + +void wg_index_hashtable_remove(struct index_hashtable *table, + struct index_hashtable_entry *entry) +{ + spin_lock_bh(&table->lock); + hlist_del_init_rcu(&entry->index_hash); + spin_unlock_bh(&table->lock); +} + +/* Returns a strong reference to a entry->peer */ +struct index_hashtable_entry * +wg_index_hashtable_lookup(struct index_hashtable *table, + const enum index_hashtable_type type_mask, + const __le32 index, struct wg_peer **peer) +{ + struct index_hashtable_entry *iter_entry, *entry = NULL; + + rcu_read_lock_bh(); + hlist_for_each_entry_rcu_bh(iter_entry, index_bucket(table, index), + index_hash) { + if (iter_entry->index == index) { + if (likely(iter_entry->type & type_mask)) + entry = iter_entry; + break; + } + } + if (likely(entry)) { + entry->peer = wg_peer_get_maybe_zero(entry->peer); + if (likely(entry->peer)) + *peer = entry->peer; + else + entry = NULL; + } + rcu_read_unlock_bh(); + return entry; +} diff --git a/drivers/net/wireguard/peerlookup.h b/drivers/net/wireguard/peerlookup.h new file mode 100644 index 000000000..ced811797 --- /dev/null +++ b/drivers/net/wireguard/peerlookup.h @@ -0,0 +1,64 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#ifndef _WG_PEERLOOKUP_H +#define _WG_PEERLOOKUP_H + +#include "messages.h" + +#include <linux/hashtable.h> +#include <linux/mutex.h> +#include <linux/siphash.h> + +struct wg_peer; + +struct pubkey_hashtable { + /* TODO: move to rhashtable */ + DECLARE_HASHTABLE(hashtable, 11); + siphash_key_t key; + struct mutex lock; +}; + +struct pubkey_hashtable *wg_pubkey_hashtable_alloc(void); +void wg_pubkey_hashtable_add(struct pubkey_hashtable *table, + struct wg_peer *peer); +void wg_pubkey_hashtable_remove(struct pubkey_hashtable *table, + struct wg_peer *peer); +struct wg_peer * +wg_pubkey_hashtable_lookup(struct pubkey_hashtable *table, + const u8 pubkey[NOISE_PUBLIC_KEY_LEN]); + +struct index_hashtable { + /* TODO: move to rhashtable */ + DECLARE_HASHTABLE(hashtable, 13); + spinlock_t lock; +}; + +enum index_hashtable_type { + INDEX_HASHTABLE_HANDSHAKE = 1U << 0, + INDEX_HASHTABLE_KEYPAIR = 1U << 1 +}; + +struct index_hashtable_entry { + struct wg_peer *peer; + struct hlist_node index_hash; + enum index_hashtable_type type; + __le32 index; +}; + +struct index_hashtable *wg_index_hashtable_alloc(void); +__le32 wg_index_hashtable_insert(struct index_hashtable *table, + struct index_hashtable_entry *entry); +bool wg_index_hashtable_replace(struct index_hashtable *table, + struct index_hashtable_entry *old, + struct index_hashtable_entry *new); +void wg_index_hashtable_remove(struct index_hashtable *table, + struct index_hashtable_entry *entry); +struct index_hashtable_entry * +wg_index_hashtable_lookup(struct index_hashtable *table, + const enum index_hashtable_type type_mask, + const __le32 index, struct wg_peer **peer); + +#endif /* _WG_PEERLOOKUP_H */ diff --git a/drivers/net/wireguard/queueing.c b/drivers/net/wireguard/queueing.c new file mode 100644 index 000000000..26d235d15 --- /dev/null +++ b/drivers/net/wireguard/queueing.c @@ -0,0 +1,109 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#include "queueing.h" +#include <linux/skb_array.h> + +struct multicore_worker __percpu * +wg_packet_percpu_multicore_worker_alloc(work_func_t function, void *ptr) +{ + int cpu; + struct multicore_worker __percpu *worker = alloc_percpu(struct multicore_worker); + + if (!worker) + return NULL; + + for_each_possible_cpu(cpu) { + per_cpu_ptr(worker, cpu)->ptr = ptr; + INIT_WORK(&per_cpu_ptr(worker, cpu)->work, function); + } + return worker; +} + +int wg_packet_queue_init(struct crypt_queue *queue, work_func_t function, + unsigned int len) +{ + int ret; + + memset(queue, 0, sizeof(*queue)); + queue->last_cpu = -1; + ret = ptr_ring_init(&queue->ring, len, GFP_KERNEL); + if (ret) + return ret; + queue->worker = wg_packet_percpu_multicore_worker_alloc(function, queue); + if (!queue->worker) { + ptr_ring_cleanup(&queue->ring, NULL); + return -ENOMEM; + } + return 0; +} + +void wg_packet_queue_free(struct crypt_queue *queue, bool purge) +{ + free_percpu(queue->worker); + WARN_ON(!purge && !__ptr_ring_empty(&queue->ring)); + ptr_ring_cleanup(&queue->ring, purge ? __skb_array_destroy_skb : NULL); +} + +#define NEXT(skb) ((skb)->prev) +#define STUB(queue) ((struct sk_buff *)&queue->empty) + +void wg_prev_queue_init(struct prev_queue *queue) +{ + NEXT(STUB(queue)) = NULL; + queue->head = queue->tail = STUB(queue); + queue->peeked = NULL; + atomic_set(&queue->count, 0); + BUILD_BUG_ON( + offsetof(struct sk_buff, next) != offsetof(struct prev_queue, empty.next) - + offsetof(struct prev_queue, empty) || + offsetof(struct sk_buff, prev) != offsetof(struct prev_queue, empty.prev) - + offsetof(struct prev_queue, empty)); +} + +static void __wg_prev_queue_enqueue(struct prev_queue *queue, struct sk_buff *skb) +{ + WRITE_ONCE(NEXT(skb), NULL); + WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb); +} + +bool wg_prev_queue_enqueue(struct prev_queue *queue, struct sk_buff *skb) +{ + if (!atomic_add_unless(&queue->count, 1, MAX_QUEUED_PACKETS)) + return false; + __wg_prev_queue_enqueue(queue, skb); + return true; +} + +struct sk_buff *wg_prev_queue_dequeue(struct prev_queue *queue) +{ + struct sk_buff *tail = queue->tail, *next = smp_load_acquire(&NEXT(tail)); + + if (tail == STUB(queue)) { + if (!next) + return NULL; + queue->tail = next; + tail = next; + next = smp_load_acquire(&NEXT(next)); + } + if (next) { + queue->tail = next; + atomic_dec(&queue->count); + return tail; + } + if (tail != READ_ONCE(queue->head)) + return NULL; + __wg_prev_queue_enqueue(queue, STUB(queue)); + next = smp_load_acquire(&NEXT(tail)); + if (next) { + queue->tail = next; + atomic_dec(&queue->count); + return tail; + } + return NULL; +} + +#undef NEXT +#undef STUB diff --git a/drivers/net/wireguard/queueing.h b/drivers/net/wireguard/queueing.h new file mode 100644 index 000000000..1d4f9196b --- /dev/null +++ b/drivers/net/wireguard/queueing.h @@ -0,0 +1,209 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#ifndef _WG_QUEUEING_H +#define _WG_QUEUEING_H + +#include "peer.h" +#include <linux/types.h> +#include <linux/skbuff.h> +#include <linux/ip.h> +#include <linux/ipv6.h> +#include <net/ip_tunnels.h> + +struct wg_device; +struct wg_peer; +struct multicore_worker; +struct crypt_queue; +struct prev_queue; +struct sk_buff; + +/* queueing.c APIs: */ +int wg_packet_queue_init(struct crypt_queue *queue, work_func_t function, + unsigned int len); +void wg_packet_queue_free(struct crypt_queue *queue, bool purge); +struct multicore_worker __percpu * +wg_packet_percpu_multicore_worker_alloc(work_func_t function, void *ptr); + +/* receive.c APIs: */ +void wg_packet_receive(struct wg_device *wg, struct sk_buff *skb); +void wg_packet_handshake_receive_worker(struct work_struct *work); +/* NAPI poll function: */ +int wg_packet_rx_poll(struct napi_struct *napi, int budget); +/* Workqueue worker: */ +void wg_packet_decrypt_worker(struct work_struct *work); + +/* send.c APIs: */ +void wg_packet_send_queued_handshake_initiation(struct wg_peer *peer, + bool is_retry); +void wg_packet_send_handshake_response(struct wg_peer *peer); +void wg_packet_send_handshake_cookie(struct wg_device *wg, + struct sk_buff *initiating_skb, + __le32 sender_index); +void wg_packet_send_keepalive(struct wg_peer *peer); +void wg_packet_purge_staged_packets(struct wg_peer *peer); +void wg_packet_send_staged_packets(struct wg_peer *peer); +/* Workqueue workers: */ +void wg_packet_handshake_send_worker(struct work_struct *work); +void wg_packet_tx_worker(struct work_struct *work); +void wg_packet_encrypt_worker(struct work_struct *work); + +enum packet_state { + PACKET_STATE_UNCRYPTED, + PACKET_STATE_CRYPTED, + PACKET_STATE_DEAD +}; + +struct packet_cb { + u64 nonce; + struct noise_keypair *keypair; + atomic_t state; + u32 mtu; + u8 ds; +}; + +#define PACKET_CB(skb) ((struct packet_cb *)((skb)->cb)) +#define PACKET_PEER(skb) (PACKET_CB(skb)->keypair->entry.peer) + +static inline bool wg_check_packet_protocol(struct sk_buff *skb) +{ + __be16 real_protocol = ip_tunnel_parse_protocol(skb); + return real_protocol && skb->protocol == real_protocol; +} + +static inline void wg_reset_packet(struct sk_buff *skb, bool encapsulating) +{ + u8 l4_hash = skb->l4_hash; + u8 sw_hash = skb->sw_hash; + u32 hash = skb->hash; + skb_scrub_packet(skb, true); + memset(&skb->headers, 0, sizeof(skb->headers)); + if (encapsulating) { + skb->l4_hash = l4_hash; + skb->sw_hash = sw_hash; + skb->hash = hash; + } + skb->queue_mapping = 0; + skb->nohdr = 0; + skb->peeked = 0; + skb->mac_len = 0; + skb->dev = NULL; +#ifdef CONFIG_NET_SCHED + skb->tc_index = 0; +#endif + skb_reset_redirect(skb); + skb->hdr_len = skb_headroom(skb); + skb_reset_mac_header(skb); + skb_reset_network_header(skb); + skb_reset_transport_header(skb); + skb_probe_transport_header(skb); + skb_reset_inner_headers(skb); +} + +static inline int wg_cpumask_choose_online(int *stored_cpu, unsigned int id) +{ + unsigned int cpu = *stored_cpu, cpu_index, i; + + if (unlikely(cpu == nr_cpumask_bits || + !cpumask_test_cpu(cpu, cpu_online_mask))) { + cpu_index = id % cpumask_weight(cpu_online_mask); + cpu = cpumask_first(cpu_online_mask); + for (i = 0; i < cpu_index; ++i) + cpu = cpumask_next(cpu, cpu_online_mask); + *stored_cpu = cpu; + } + return cpu; +} + +/* This function is racy, in the sense that it's called while last_cpu is + * unlocked, so it could return the same CPU twice. Adding locking or using + * atomic sequence numbers is slower though, and the consequences of racing are + * harmless, so live with it. + */ +static inline int wg_cpumask_next_online(int *last_cpu) +{ + int cpu = cpumask_next(*last_cpu, cpu_online_mask); + if (cpu >= nr_cpu_ids) + cpu = cpumask_first(cpu_online_mask); + *last_cpu = cpu; + return cpu; +} + +void wg_prev_queue_init(struct prev_queue *queue); + +/* Multi producer */ +bool wg_prev_queue_enqueue(struct prev_queue *queue, struct sk_buff *skb); + +/* Single consumer */ +struct sk_buff *wg_prev_queue_dequeue(struct prev_queue *queue); + +/* Single consumer */ +static inline struct sk_buff *wg_prev_queue_peek(struct prev_queue *queue) +{ + if (queue->peeked) + return queue->peeked; + queue->peeked = wg_prev_queue_dequeue(queue); + return queue->peeked; +} + +/* Single consumer */ +static inline void wg_prev_queue_drop_peeked(struct prev_queue *queue) +{ + queue->peeked = NULL; +} + +static inline int wg_queue_enqueue_per_device_and_peer( + struct crypt_queue *device_queue, struct prev_queue *peer_queue, + struct sk_buff *skb, struct workqueue_struct *wq) +{ + int cpu; + + atomic_set_release(&PACKET_CB(skb)->state, PACKET_STATE_UNCRYPTED); + /* We first queue this up for the peer ingestion, but the consumer + * will wait for the state to change to CRYPTED or DEAD before. + */ + if (unlikely(!wg_prev_queue_enqueue(peer_queue, skb))) + return -ENOSPC; + + /* Then we queue it up in the device queue, which consumes the + * packet as soon as it can. + */ + cpu = wg_cpumask_next_online(&device_queue->last_cpu); + if (unlikely(ptr_ring_produce_bh(&device_queue->ring, skb))) + return -EPIPE; + queue_work_on(cpu, wq, &per_cpu_ptr(device_queue->worker, cpu)->work); + return 0; +} + +static inline void wg_queue_enqueue_per_peer_tx(struct sk_buff *skb, enum packet_state state) +{ + /* We take a reference, because as soon as we call atomic_set, the + * peer can be freed from below us. + */ + struct wg_peer *peer = wg_peer_get(PACKET_PEER(skb)); + + atomic_set_release(&PACKET_CB(skb)->state, state); + queue_work_on(wg_cpumask_choose_online(&peer->serial_work_cpu, peer->internal_id), + peer->device->packet_crypt_wq, &peer->transmit_packet_work); + wg_peer_put(peer); +} + +static inline void wg_queue_enqueue_per_peer_rx(struct sk_buff *skb, enum packet_state state) +{ + /* We take a reference, because as soon as we call atomic_set, the + * peer can be freed from below us. + */ + struct wg_peer *peer = wg_peer_get(PACKET_PEER(skb)); + + atomic_set_release(&PACKET_CB(skb)->state, state); + napi_schedule(&peer->napi); + wg_peer_put(peer); +} + +#ifdef DEBUG +bool wg_packet_counter_selftest(void); +#endif + +#endif /* _WG_QUEUEING_H */ diff --git a/drivers/net/wireguard/ratelimiter.c b/drivers/net/wireguard/ratelimiter.c new file mode 100644 index 000000000..dd55e5c26 --- /dev/null +++ b/drivers/net/wireguard/ratelimiter.c @@ -0,0 +1,223 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#include "ratelimiter.h" +#include <linux/siphash.h> +#include <linux/mm.h> +#include <linux/slab.h> +#include <net/ip.h> + +static struct kmem_cache *entry_cache; +static hsiphash_key_t key; +static spinlock_t table_lock = __SPIN_LOCK_UNLOCKED("ratelimiter_table_lock"); +static DEFINE_MUTEX(init_lock); +static u64 init_refcnt; /* Protected by init_lock, hence not atomic. */ +static atomic_t total_entries = ATOMIC_INIT(0); +static unsigned int max_entries, table_size; +static void wg_ratelimiter_gc_entries(struct work_struct *); +static DECLARE_DEFERRABLE_WORK(gc_work, wg_ratelimiter_gc_entries); +static struct hlist_head *table_v4; +#if IS_ENABLED(CONFIG_IPV6) +static struct hlist_head *table_v6; +#endif + +struct ratelimiter_entry { + u64 last_time_ns, tokens, ip; + void *net; + spinlock_t lock; + struct hlist_node hash; + struct rcu_head rcu; +}; + +enum { + PACKETS_PER_SECOND = 20, + PACKETS_BURSTABLE = 5, + PACKET_COST = NSEC_PER_SEC / PACKETS_PER_SECOND, + TOKEN_MAX = PACKET_COST * PACKETS_BURSTABLE +}; + +static void entry_free(struct rcu_head *rcu) +{ + kmem_cache_free(entry_cache, + container_of(rcu, struct ratelimiter_entry, rcu)); + atomic_dec(&total_entries); +} + +static void entry_uninit(struct ratelimiter_entry *entry) +{ + hlist_del_rcu(&entry->hash); + call_rcu(&entry->rcu, entry_free); +} + +/* Calling this function with a NULL work uninits all entries. */ +static void wg_ratelimiter_gc_entries(struct work_struct *work) +{ + const u64 now = ktime_get_coarse_boottime_ns(); + struct ratelimiter_entry *entry; + struct hlist_node *temp; + unsigned int i; + + for (i = 0; i < table_size; ++i) { + spin_lock(&table_lock); + hlist_for_each_entry_safe(entry, temp, &table_v4[i], hash) { + if (unlikely(!work) || + now - entry->last_time_ns > NSEC_PER_SEC) + entry_uninit(entry); + } +#if IS_ENABLED(CONFIG_IPV6) + hlist_for_each_entry_safe(entry, temp, &table_v6[i], hash) { + if (unlikely(!work) || + now - entry->last_time_ns > NSEC_PER_SEC) + entry_uninit(entry); + } +#endif + spin_unlock(&table_lock); + if (likely(work)) + cond_resched(); + } + if (likely(work)) + queue_delayed_work(system_power_efficient_wq, &gc_work, HZ); +} + +bool wg_ratelimiter_allow(struct sk_buff *skb, struct net *net) +{ + /* We only take the bottom half of the net pointer, so that we can hash + * 3 words in the end. This way, siphash's len param fits into the final + * u32, and we don't incur an extra round. + */ + const u32 net_word = (unsigned long)net; + struct ratelimiter_entry *entry; + struct hlist_head *bucket; + u64 ip; + + if (skb->protocol == htons(ETH_P_IP)) { + ip = (u64 __force)ip_hdr(skb)->saddr; + bucket = &table_v4[hsiphash_2u32(net_word, ip, &key) & + (table_size - 1)]; + } +#if IS_ENABLED(CONFIG_IPV6) + else if (skb->protocol == htons(ETH_P_IPV6)) { + /* Only use 64 bits, so as to ratelimit the whole /64. */ + memcpy(&ip, &ipv6_hdr(skb)->saddr, sizeof(ip)); + bucket = &table_v6[hsiphash_3u32(net_word, ip >> 32, ip, &key) & + (table_size - 1)]; + } +#endif + else + return false; + rcu_read_lock(); + hlist_for_each_entry_rcu(entry, bucket, hash) { + if (entry->net == net && entry->ip == ip) { + u64 now, tokens; + bool ret; + /* Quasi-inspired by nft_limit.c, but this is actually a + * slightly different algorithm. Namely, we incorporate + * the burst as part of the maximum tokens, rather than + * as part of the rate. + */ + spin_lock(&entry->lock); + now = ktime_get_coarse_boottime_ns(); + tokens = min_t(u64, TOKEN_MAX, + entry->tokens + now - + entry->last_time_ns); + entry->last_time_ns = now; + ret = tokens >= PACKET_COST; + entry->tokens = ret ? tokens - PACKET_COST : tokens; + spin_unlock(&entry->lock); + rcu_read_unlock(); + return ret; + } + } + rcu_read_unlock(); + + if (atomic_inc_return(&total_entries) > max_entries) + goto err_oom; + + entry = kmem_cache_alloc(entry_cache, GFP_KERNEL); + if (unlikely(!entry)) + goto err_oom; + + entry->net = net; + entry->ip = ip; + INIT_HLIST_NODE(&entry->hash); + spin_lock_init(&entry->lock); + entry->last_time_ns = ktime_get_coarse_boottime_ns(); + entry->tokens = TOKEN_MAX - PACKET_COST; + spin_lock(&table_lock); + hlist_add_head_rcu(&entry->hash, bucket); + spin_unlock(&table_lock); + return true; + +err_oom: + atomic_dec(&total_entries); + return false; +} + +int wg_ratelimiter_init(void) +{ + mutex_lock(&init_lock); + if (++init_refcnt != 1) + goto out; + + entry_cache = KMEM_CACHE(ratelimiter_entry, 0); + if (!entry_cache) + goto err; + + /* xt_hashlimit.c uses a slightly different algorithm for ratelimiting, + * but what it shares in common is that it uses a massive hashtable. So, + * we borrow their wisdom about good table sizes on different systems + * dependent on RAM. This calculation here comes from there. + */ + table_size = (totalram_pages() > (1U << 30) / PAGE_SIZE) ? 8192 : + max_t(unsigned long, 16, roundup_pow_of_two( + (totalram_pages() << PAGE_SHIFT) / + (1U << 14) / sizeof(struct hlist_head))); + max_entries = table_size * 8; + + table_v4 = kvcalloc(table_size, sizeof(*table_v4), GFP_KERNEL); + if (unlikely(!table_v4)) + goto err_kmemcache; + +#if IS_ENABLED(CONFIG_IPV6) + table_v6 = kvcalloc(table_size, sizeof(*table_v6), GFP_KERNEL); + if (unlikely(!table_v6)) { + kvfree(table_v4); + goto err_kmemcache; + } +#endif + + queue_delayed_work(system_power_efficient_wq, &gc_work, HZ); + get_random_bytes(&key, sizeof(key)); +out: + mutex_unlock(&init_lock); + return 0; + +err_kmemcache: + kmem_cache_destroy(entry_cache); +err: + --init_refcnt; + mutex_unlock(&init_lock); + return -ENOMEM; +} + +void wg_ratelimiter_uninit(void) +{ + mutex_lock(&init_lock); + if (!init_refcnt || --init_refcnt) + goto out; + + cancel_delayed_work_sync(&gc_work); + wg_ratelimiter_gc_entries(NULL); + rcu_barrier(); + kvfree(table_v4); +#if IS_ENABLED(CONFIG_IPV6) + kvfree(table_v6); +#endif + kmem_cache_destroy(entry_cache); +out: + mutex_unlock(&init_lock); +} + +#include "selftest/ratelimiter.c" diff --git a/drivers/net/wireguard/ratelimiter.h b/drivers/net/wireguard/ratelimiter.h new file mode 100644 index 000000000..83067f71e --- /dev/null +++ b/drivers/net/wireguard/ratelimiter.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#ifndef _WG_RATELIMITER_H +#define _WG_RATELIMITER_H + +#include <linux/skbuff.h> + +int wg_ratelimiter_init(void); +void wg_ratelimiter_uninit(void); +bool wg_ratelimiter_allow(struct sk_buff *skb, struct net *net); + +#ifdef DEBUG +bool wg_ratelimiter_selftest(void); +#endif + +#endif /* _WG_RATELIMITER_H */ diff --git a/drivers/net/wireguard/receive.c b/drivers/net/wireguard/receive.c new file mode 100644 index 000000000..a176653c8 --- /dev/null +++ b/drivers/net/wireguard/receive.c @@ -0,0 +1,586 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#include "queueing.h" +#include "device.h" +#include "peer.h" +#include "timers.h" +#include "messages.h" +#include "cookie.h" +#include "socket.h" + +#include <linux/ip.h> +#include <linux/ipv6.h> +#include <linux/udp.h> +#include <net/ip_tunnels.h> + +/* Must be called with bh disabled. */ +static void update_rx_stats(struct wg_peer *peer, size_t len) +{ + dev_sw_netstats_rx_add(peer->device->dev, len); + peer->rx_bytes += len; +} + +#define SKB_TYPE_LE32(skb) (((struct message_header *)(skb)->data)->type) + +static size_t validate_header_len(struct sk_buff *skb) +{ + if (unlikely(skb->len < sizeof(struct message_header))) + return 0; + if (SKB_TYPE_LE32(skb) == cpu_to_le32(MESSAGE_DATA) && + skb->len >= MESSAGE_MINIMUM_LENGTH) + return sizeof(struct message_data); + if (SKB_TYPE_LE32(skb) == cpu_to_le32(MESSAGE_HANDSHAKE_INITIATION) && + skb->len == sizeof(struct message_handshake_initiation)) + return sizeof(struct message_handshake_initiation); + if (SKB_TYPE_LE32(skb) == cpu_to_le32(MESSAGE_HANDSHAKE_RESPONSE) && + skb->len == sizeof(struct message_handshake_response)) + return sizeof(struct message_handshake_response); + if (SKB_TYPE_LE32(skb) == cpu_to_le32(MESSAGE_HANDSHAKE_COOKIE) && + skb->len == sizeof(struct message_handshake_cookie)) + return sizeof(struct message_handshake_cookie); + return 0; +} + +static int prepare_skb_header(struct sk_buff *skb, struct wg_device *wg) +{ + size_t data_offset, data_len, header_len; + struct udphdr *udp; + + if (unlikely(!wg_check_packet_protocol(skb) || + skb_transport_header(skb) < skb->head || + (skb_transport_header(skb) + sizeof(struct udphdr)) > + skb_tail_pointer(skb))) + return -EINVAL; /* Bogus IP header */ + udp = udp_hdr(skb); + data_offset = (u8 *)udp - skb->data; + if (unlikely(data_offset > U16_MAX || + data_offset + sizeof(struct udphdr) > skb->len)) + /* Packet has offset at impossible location or isn't big enough + * to have UDP fields. + */ + return -EINVAL; + data_len = ntohs(udp->len); + if (unlikely(data_len < sizeof(struct udphdr) || + data_len > skb->len - data_offset)) + /* UDP packet is reporting too small of a size or lying about + * its size. + */ + return -EINVAL; + data_len -= sizeof(struct udphdr); + data_offset = (u8 *)udp + sizeof(struct udphdr) - skb->data; + if (unlikely(!pskb_may_pull(skb, + data_offset + sizeof(struct message_header)) || + pskb_trim(skb, data_len + data_offset) < 0)) + return -EINVAL; + skb_pull(skb, data_offset); + if (unlikely(skb->len != data_len)) + /* Final len does not agree with calculated len */ + return -EINVAL; + header_len = validate_header_len(skb); + if (unlikely(!header_len)) + return -EINVAL; + __skb_push(skb, data_offset); + if (unlikely(!pskb_may_pull(skb, data_offset + header_len))) + return -EINVAL; + __skb_pull(skb, data_offset); + return 0; +} + +static void wg_receive_handshake_packet(struct wg_device *wg, + struct sk_buff *skb) +{ + enum cookie_mac_state mac_state; + struct wg_peer *peer = NULL; + /* This is global, so that our load calculation applies to the whole + * system. We don't care about races with it at all. + */ + static u64 last_under_load; + bool packet_needs_cookie; + bool under_load; + + if (SKB_TYPE_LE32(skb) == cpu_to_le32(MESSAGE_HANDSHAKE_COOKIE)) { + net_dbg_skb_ratelimited("%s: Receiving cookie response from %pISpfsc\n", + wg->dev->name, skb); + wg_cookie_message_consume( + (struct message_handshake_cookie *)skb->data, wg); + return; + } + + under_load = atomic_read(&wg->handshake_queue_len) >= + MAX_QUEUED_INCOMING_HANDSHAKES / 8; + if (under_load) { + last_under_load = ktime_get_coarse_boottime_ns(); + } else if (last_under_load) { + under_load = !wg_birthdate_has_expired(last_under_load, 1); + if (!under_load) + last_under_load = 0; + } + mac_state = wg_cookie_validate_packet(&wg->cookie_checker, skb, + under_load); + if ((under_load && mac_state == VALID_MAC_WITH_COOKIE) || + (!under_load && mac_state == VALID_MAC_BUT_NO_COOKIE)) { + packet_needs_cookie = false; + } else if (under_load && mac_state == VALID_MAC_BUT_NO_COOKIE) { + packet_needs_cookie = true; + } else { + net_dbg_skb_ratelimited("%s: Invalid MAC of handshake, dropping packet from %pISpfsc\n", + wg->dev->name, skb); + return; + } + + switch (SKB_TYPE_LE32(skb)) { + case cpu_to_le32(MESSAGE_HANDSHAKE_INITIATION): { + struct message_handshake_initiation *message = + (struct message_handshake_initiation *)skb->data; + + if (packet_needs_cookie) { + wg_packet_send_handshake_cookie(wg, skb, + message->sender_index); + return; + } + peer = wg_noise_handshake_consume_initiation(message, wg); + if (unlikely(!peer)) { + net_dbg_skb_ratelimited("%s: Invalid handshake initiation from %pISpfsc\n", + wg->dev->name, skb); + return; + } + wg_socket_set_peer_endpoint_from_skb(peer, skb); + net_dbg_ratelimited("%s: Receiving handshake initiation from peer %llu (%pISpfsc)\n", + wg->dev->name, peer->internal_id, + &peer->endpoint.addr); + wg_packet_send_handshake_response(peer); + break; + } + case cpu_to_le32(MESSAGE_HANDSHAKE_RESPONSE): { + struct message_handshake_response *message = + (struct message_handshake_response *)skb->data; + + if (packet_needs_cookie) { + wg_packet_send_handshake_cookie(wg, skb, + message->sender_index); + return; + } + peer = wg_noise_handshake_consume_response(message, wg); + if (unlikely(!peer)) { + net_dbg_skb_ratelimited("%s: Invalid handshake response from %pISpfsc\n", + wg->dev->name, skb); + return; + } + wg_socket_set_peer_endpoint_from_skb(peer, skb); + net_dbg_ratelimited("%s: Receiving handshake response from peer %llu (%pISpfsc)\n", + wg->dev->name, peer->internal_id, + &peer->endpoint.addr); + if (wg_noise_handshake_begin_session(&peer->handshake, + &peer->keypairs)) { + wg_timers_session_derived(peer); + wg_timers_handshake_complete(peer); + /* Calling this function will either send any existing + * packets in the queue and not send a keepalive, which + * is the best case, Or, if there's nothing in the + * queue, it will send a keepalive, in order to give + * immediate confirmation of the session. + */ + wg_packet_send_keepalive(peer); + } + break; + } + } + + if (unlikely(!peer)) { + WARN(1, "Somehow a wrong type of packet wound up in the handshake queue!\n"); + return; + } + + local_bh_disable(); + update_rx_stats(peer, skb->len); + local_bh_enable(); + + wg_timers_any_authenticated_packet_received(peer); + wg_timers_any_authenticated_packet_traversal(peer); + wg_peer_put(peer); +} + +void wg_packet_handshake_receive_worker(struct work_struct *work) +{ + struct crypt_queue *queue = container_of(work, struct multicore_worker, work)->ptr; + struct wg_device *wg = container_of(queue, struct wg_device, handshake_queue); + struct sk_buff *skb; + + while ((skb = ptr_ring_consume_bh(&queue->ring)) != NULL) { + wg_receive_handshake_packet(wg, skb); + dev_kfree_skb(skb); + atomic_dec(&wg->handshake_queue_len); + cond_resched(); + } +} + +static void keep_key_fresh(struct wg_peer *peer) +{ + struct noise_keypair *keypair; + bool send; + + if (peer->sent_lastminute_handshake) + return; + + rcu_read_lock_bh(); + keypair = rcu_dereference_bh(peer->keypairs.current_keypair); + send = keypair && READ_ONCE(keypair->sending.is_valid) && + keypair->i_am_the_initiator && + wg_birthdate_has_expired(keypair->sending.birthdate, + REJECT_AFTER_TIME - KEEPALIVE_TIMEOUT - REKEY_TIMEOUT); + rcu_read_unlock_bh(); + + if (unlikely(send)) { + peer->sent_lastminute_handshake = true; + wg_packet_send_queued_handshake_initiation(peer, false); + } +} + +static bool decrypt_packet(struct sk_buff *skb, struct noise_keypair *keypair) +{ + struct scatterlist sg[MAX_SKB_FRAGS + 8]; + struct sk_buff *trailer; + unsigned int offset; + int num_frags; + + if (unlikely(!keypair)) + return false; + + if (unlikely(!READ_ONCE(keypair->receiving.is_valid) || + wg_birthdate_has_expired(keypair->receiving.birthdate, REJECT_AFTER_TIME) || + keypair->receiving_counter.counter >= REJECT_AFTER_MESSAGES)) { + WRITE_ONCE(keypair->receiving.is_valid, false); + return false; + } + + PACKET_CB(skb)->nonce = + le64_to_cpu(((struct message_data *)skb->data)->counter); + + /* We ensure that the network header is part of the packet before we + * call skb_cow_data, so that there's no chance that data is removed + * from the skb, so that later we can extract the original endpoint. + */ + offset = skb->data - skb_network_header(skb); + skb_push(skb, offset); + num_frags = skb_cow_data(skb, 0, &trailer); + offset += sizeof(struct message_data); + skb_pull(skb, offset); + if (unlikely(num_frags < 0 || num_frags > ARRAY_SIZE(sg))) + return false; + + sg_init_table(sg, num_frags); + if (skb_to_sgvec(skb, sg, 0, skb->len) <= 0) + return false; + + if (!chacha20poly1305_decrypt_sg_inplace(sg, skb->len, NULL, 0, + PACKET_CB(skb)->nonce, + keypair->receiving.key)) + return false; + + /* Another ugly situation of pushing and pulling the header so as to + * keep endpoint information intact. + */ + skb_push(skb, offset); + if (pskb_trim(skb, skb->len - noise_encrypted_len(0))) + return false; + skb_pull(skb, offset); + + return true; +} + +/* This is RFC6479, a replay detection bitmap algorithm that avoids bitshifts */ +static bool counter_validate(struct noise_replay_counter *counter, u64 their_counter) +{ + unsigned long index, index_current, top, i; + bool ret = false; + + spin_lock_bh(&counter->lock); + + if (unlikely(counter->counter >= REJECT_AFTER_MESSAGES + 1 || + their_counter >= REJECT_AFTER_MESSAGES)) + goto out; + + ++their_counter; + + if (unlikely((COUNTER_WINDOW_SIZE + their_counter) < + counter->counter)) + goto out; + + index = their_counter >> ilog2(BITS_PER_LONG); + + if (likely(their_counter > counter->counter)) { + index_current = counter->counter >> ilog2(BITS_PER_LONG); + top = min_t(unsigned long, index - index_current, + COUNTER_BITS_TOTAL / BITS_PER_LONG); + for (i = 1; i <= top; ++i) + counter->backtrack[(i + index_current) & + ((COUNTER_BITS_TOTAL / BITS_PER_LONG) - 1)] = 0; + counter->counter = their_counter; + } + + index &= (COUNTER_BITS_TOTAL / BITS_PER_LONG) - 1; + ret = !test_and_set_bit(their_counter & (BITS_PER_LONG - 1), + &counter->backtrack[index]); + +out: + spin_unlock_bh(&counter->lock); + return ret; +} + +#include "selftest/counter.c" + +static void wg_packet_consume_data_done(struct wg_peer *peer, + struct sk_buff *skb, + struct endpoint *endpoint) +{ + struct net_device *dev = peer->device->dev; + unsigned int len, len_before_trim; + struct wg_peer *routed_peer; + + wg_socket_set_peer_endpoint(peer, endpoint); + + if (unlikely(wg_noise_received_with_keypair(&peer->keypairs, + PACKET_CB(skb)->keypair))) { + wg_timers_handshake_complete(peer); + wg_packet_send_staged_packets(peer); + } + + keep_key_fresh(peer); + + wg_timers_any_authenticated_packet_received(peer); + wg_timers_any_authenticated_packet_traversal(peer); + + /* A packet with length 0 is a keepalive packet */ + if (unlikely(!skb->len)) { + update_rx_stats(peer, message_data_len(0)); + net_dbg_ratelimited("%s: Receiving keepalive packet from peer %llu (%pISpfsc)\n", + dev->name, peer->internal_id, + &peer->endpoint.addr); + goto packet_processed; + } + + wg_timers_data_received(peer); + + if (unlikely(skb_network_header(skb) < skb->head)) + goto dishonest_packet_size; + if (unlikely(!(pskb_network_may_pull(skb, sizeof(struct iphdr)) && + (ip_hdr(skb)->version == 4 || + (ip_hdr(skb)->version == 6 && + pskb_network_may_pull(skb, sizeof(struct ipv6hdr))))))) + goto dishonest_packet_type; + + skb->dev = dev; + /* We've already verified the Poly1305 auth tag, which means this packet + * was not modified in transit. We can therefore tell the networking + * stack that all checksums of every layer of encapsulation have already + * been checked "by the hardware" and therefore is unnecessary to check + * again in software. + */ + skb->ip_summed = CHECKSUM_UNNECESSARY; + skb->csum_level = ~0; /* All levels */ + skb->protocol = ip_tunnel_parse_protocol(skb); + if (skb->protocol == htons(ETH_P_IP)) { + len = ntohs(ip_hdr(skb)->tot_len); + if (unlikely(len < sizeof(struct iphdr))) + goto dishonest_packet_size; + INET_ECN_decapsulate(skb, PACKET_CB(skb)->ds, ip_hdr(skb)->tos); + } else if (skb->protocol == htons(ETH_P_IPV6)) { + len = ntohs(ipv6_hdr(skb)->payload_len) + + sizeof(struct ipv6hdr); + INET_ECN_decapsulate(skb, PACKET_CB(skb)->ds, ipv6_get_dsfield(ipv6_hdr(skb))); + } else { + goto dishonest_packet_type; + } + + if (unlikely(len > skb->len)) + goto dishonest_packet_size; + len_before_trim = skb->len; + if (unlikely(pskb_trim(skb, len))) + goto packet_processed; + + routed_peer = wg_allowedips_lookup_src(&peer->device->peer_allowedips, + skb); + wg_peer_put(routed_peer); /* We don't need the extra reference. */ + + if (unlikely(routed_peer != peer)) + goto dishonest_packet_peer; + + napi_gro_receive(&peer->napi, skb); + update_rx_stats(peer, message_data_len(len_before_trim)); + return; + +dishonest_packet_peer: + net_dbg_skb_ratelimited("%s: Packet has unallowed src IP (%pISc) from peer %llu (%pISpfsc)\n", + dev->name, skb, peer->internal_id, + &peer->endpoint.addr); + DEV_STATS_INC(dev, rx_errors); + DEV_STATS_INC(dev, rx_frame_errors); + goto packet_processed; +dishonest_packet_type: + net_dbg_ratelimited("%s: Packet is neither ipv4 nor ipv6 from peer %llu (%pISpfsc)\n", + dev->name, peer->internal_id, &peer->endpoint.addr); + DEV_STATS_INC(dev, rx_errors); + DEV_STATS_INC(dev, rx_frame_errors); + goto packet_processed; +dishonest_packet_size: + net_dbg_ratelimited("%s: Packet has incorrect size from peer %llu (%pISpfsc)\n", + dev->name, peer->internal_id, &peer->endpoint.addr); + DEV_STATS_INC(dev, rx_errors); + DEV_STATS_INC(dev, rx_length_errors); + goto packet_processed; +packet_processed: + dev_kfree_skb(skb); +} + +int wg_packet_rx_poll(struct napi_struct *napi, int budget) +{ + struct wg_peer *peer = container_of(napi, struct wg_peer, napi); + struct noise_keypair *keypair; + struct endpoint endpoint; + enum packet_state state; + struct sk_buff *skb; + int work_done = 0; + bool free; + + if (unlikely(budget <= 0)) + return 0; + + while ((skb = wg_prev_queue_peek(&peer->rx_queue)) != NULL && + (state = atomic_read_acquire(&PACKET_CB(skb)->state)) != + PACKET_STATE_UNCRYPTED) { + wg_prev_queue_drop_peeked(&peer->rx_queue); + keypair = PACKET_CB(skb)->keypair; + free = true; + + if (unlikely(state != PACKET_STATE_CRYPTED)) + goto next; + + if (unlikely(!counter_validate(&keypair->receiving_counter, + PACKET_CB(skb)->nonce))) { + net_dbg_ratelimited("%s: Packet has invalid nonce %llu (max %llu)\n", + peer->device->dev->name, + PACKET_CB(skb)->nonce, + keypair->receiving_counter.counter); + goto next; + } + + if (unlikely(wg_socket_endpoint_from_skb(&endpoint, skb))) + goto next; + + wg_reset_packet(skb, false); + wg_packet_consume_data_done(peer, skb, &endpoint); + free = false; + +next: + wg_noise_keypair_put(keypair, false); + wg_peer_put(peer); + if (unlikely(free)) + dev_kfree_skb(skb); + + if (++work_done >= budget) + break; + } + + if (work_done < budget) + napi_complete_done(napi, work_done); + + return work_done; +} + +void wg_packet_decrypt_worker(struct work_struct *work) +{ + struct crypt_queue *queue = container_of(work, struct multicore_worker, + work)->ptr; + struct sk_buff *skb; + + while ((skb = ptr_ring_consume_bh(&queue->ring)) != NULL) { + enum packet_state state = + likely(decrypt_packet(skb, PACKET_CB(skb)->keypair)) ? + PACKET_STATE_CRYPTED : PACKET_STATE_DEAD; + wg_queue_enqueue_per_peer_rx(skb, state); + if (need_resched()) + cond_resched(); + } +} + +static void wg_packet_consume_data(struct wg_device *wg, struct sk_buff *skb) +{ + __le32 idx = ((struct message_data *)skb->data)->key_idx; + struct wg_peer *peer = NULL; + int ret; + + rcu_read_lock_bh(); + PACKET_CB(skb)->keypair = + (struct noise_keypair *)wg_index_hashtable_lookup( + wg->index_hashtable, INDEX_HASHTABLE_KEYPAIR, idx, + &peer); + if (unlikely(!wg_noise_keypair_get(PACKET_CB(skb)->keypair))) + goto err_keypair; + + if (unlikely(READ_ONCE(peer->is_dead))) + goto err; + + ret = wg_queue_enqueue_per_device_and_peer(&wg->decrypt_queue, &peer->rx_queue, skb, + wg->packet_crypt_wq); + if (unlikely(ret == -EPIPE)) + wg_queue_enqueue_per_peer_rx(skb, PACKET_STATE_DEAD); + if (likely(!ret || ret == -EPIPE)) { + rcu_read_unlock_bh(); + return; + } +err: + wg_noise_keypair_put(PACKET_CB(skb)->keypair, false); +err_keypair: + rcu_read_unlock_bh(); + wg_peer_put(peer); + dev_kfree_skb(skb); +} + +void wg_packet_receive(struct wg_device *wg, struct sk_buff *skb) +{ + if (unlikely(prepare_skb_header(skb, wg) < 0)) + goto err; + switch (SKB_TYPE_LE32(skb)) { + case cpu_to_le32(MESSAGE_HANDSHAKE_INITIATION): + case cpu_to_le32(MESSAGE_HANDSHAKE_RESPONSE): + case cpu_to_le32(MESSAGE_HANDSHAKE_COOKIE): { + int cpu, ret = -EBUSY; + + if (unlikely(!rng_is_initialized())) + goto drop; + if (atomic_read(&wg->handshake_queue_len) > MAX_QUEUED_INCOMING_HANDSHAKES / 2) { + if (spin_trylock_bh(&wg->handshake_queue.ring.producer_lock)) { + ret = __ptr_ring_produce(&wg->handshake_queue.ring, skb); + spin_unlock_bh(&wg->handshake_queue.ring.producer_lock); + } + } else + ret = ptr_ring_produce_bh(&wg->handshake_queue.ring, skb); + if (ret) { + drop: + net_dbg_skb_ratelimited("%s: Dropping handshake packet from %pISpfsc\n", + wg->dev->name, skb); + goto err; + } + atomic_inc(&wg->handshake_queue_len); + cpu = wg_cpumask_next_online(&wg->handshake_queue.last_cpu); + /* Queues up a call to packet_process_queued_handshake_packets(skb): */ + queue_work_on(cpu, wg->handshake_receive_wq, + &per_cpu_ptr(wg->handshake_queue.worker, cpu)->work); + break; + } + case cpu_to_le32(MESSAGE_DATA): + PACKET_CB(skb)->ds = ip_tunnel_get_dsfield(ip_hdr(skb), skb); + wg_packet_consume_data(wg, skb); + break; + default: + WARN(1, "Non-exhaustive parsing of packet header lead to unknown packet type!\n"); + goto err; + } + return; + +err: + dev_kfree_skb(skb); +} diff --git a/drivers/net/wireguard/selftest/allowedips.c b/drivers/net/wireguard/selftest/allowedips.c new file mode 100644 index 000000000..c51c794e7 --- /dev/null +++ b/drivers/net/wireguard/selftest/allowedips.c @@ -0,0 +1,680 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + * + * This contains some basic static unit tests for the allowedips data structure. + * It also has two additional modes that are disabled and meant to be used by + * folks directly playing with this file. If you define the macro + * DEBUG_PRINT_TRIE_GRAPHVIZ to be 1, then every time there's a full tree in + * memory, it will be printed out as KERN_DEBUG in a format that can be passed + * to graphviz (the dot command) to visualize it. If you define the macro + * DEBUG_RANDOM_TRIE to be 1, then there will be an extremely costly set of + * randomized tests done against a trivial implementation, which may take + * upwards of a half-hour to complete. There's no set of users who should be + * enabling these, and the only developers that should go anywhere near these + * nobs are the ones who are reading this comment. + */ + +#ifdef DEBUG + +#include <linux/siphash.h> + +static __init void print_node(struct allowedips_node *node, u8 bits) +{ + char *fmt_connection = KERN_DEBUG "\t\"%p/%d\" -> \"%p/%d\";\n"; + char *fmt_declaration = KERN_DEBUG "\t\"%p/%d\"[style=%s, color=\"#%06x\"];\n"; + u8 ip1[16], ip2[16], cidr1, cidr2; + char *style = "dotted"; + u32 color = 0; + + if (node == NULL) + return; + if (bits == 32) { + fmt_connection = KERN_DEBUG "\t\"%pI4/%d\" -> \"%pI4/%d\";\n"; + fmt_declaration = KERN_DEBUG "\t\"%pI4/%d\"[style=%s, color=\"#%06x\"];\n"; + } else if (bits == 128) { + fmt_connection = KERN_DEBUG "\t\"%pI6/%d\" -> \"%pI6/%d\";\n"; + fmt_declaration = KERN_DEBUG "\t\"%pI6/%d\"[style=%s, color=\"#%06x\"];\n"; + } + if (node->peer) { + hsiphash_key_t key = { { 0 } }; + + memcpy(&key, &node->peer, sizeof(node->peer)); + color = hsiphash_1u32(0xdeadbeef, &key) % 200 << 16 | + hsiphash_1u32(0xbabecafe, &key) % 200 << 8 | + hsiphash_1u32(0xabad1dea, &key) % 200; + style = "bold"; + } + wg_allowedips_read_node(node, ip1, &cidr1); + printk(fmt_declaration, ip1, cidr1, style, color); + if (node->bit[0]) { + wg_allowedips_read_node(rcu_dereference_raw(node->bit[0]), ip2, &cidr2); + printk(fmt_connection, ip1, cidr1, ip2, cidr2); + } + if (node->bit[1]) { + wg_allowedips_read_node(rcu_dereference_raw(node->bit[1]), ip2, &cidr2); + printk(fmt_connection, ip1, cidr1, ip2, cidr2); + } + if (node->bit[0]) + print_node(rcu_dereference_raw(node->bit[0]), bits); + if (node->bit[1]) + print_node(rcu_dereference_raw(node->bit[1]), bits); +} + +static __init void print_tree(struct allowedips_node __rcu *top, u8 bits) +{ + printk(KERN_DEBUG "digraph trie {\n"); + print_node(rcu_dereference_raw(top), bits); + printk(KERN_DEBUG "}\n"); +} + +enum { + NUM_PEERS = 2000, + NUM_RAND_ROUTES = 400, + NUM_MUTATED_ROUTES = 100, + NUM_QUERIES = NUM_RAND_ROUTES * NUM_MUTATED_ROUTES * 30 +}; + +struct horrible_allowedips { + struct hlist_head head; +}; + +struct horrible_allowedips_node { + struct hlist_node table; + union nf_inet_addr ip; + union nf_inet_addr mask; + u8 ip_version; + void *value; +}; + +static __init void horrible_allowedips_init(struct horrible_allowedips *table) +{ + INIT_HLIST_HEAD(&table->head); +} + +static __init void horrible_allowedips_free(struct horrible_allowedips *table) +{ + struct horrible_allowedips_node *node; + struct hlist_node *h; + + hlist_for_each_entry_safe(node, h, &table->head, table) { + hlist_del(&node->table); + kfree(node); + } +} + +static __init inline union nf_inet_addr horrible_cidr_to_mask(u8 cidr) +{ + union nf_inet_addr mask; + + memset(&mask, 0, sizeof(mask)); + memset(&mask.all, 0xff, cidr / 8); + if (cidr % 32) + mask.all[cidr / 32] = (__force u32)htonl( + (0xFFFFFFFFUL << (32 - (cidr % 32))) & 0xFFFFFFFFUL); + return mask; +} + +static __init inline u8 horrible_mask_to_cidr(union nf_inet_addr subnet) +{ + return hweight32(subnet.all[0]) + hweight32(subnet.all[1]) + + hweight32(subnet.all[2]) + hweight32(subnet.all[3]); +} + +static __init inline void +horrible_mask_self(struct horrible_allowedips_node *node) +{ + if (node->ip_version == 4) { + node->ip.ip &= node->mask.ip; + } else if (node->ip_version == 6) { + node->ip.ip6[0] &= node->mask.ip6[0]; + node->ip.ip6[1] &= node->mask.ip6[1]; + node->ip.ip6[2] &= node->mask.ip6[2]; + node->ip.ip6[3] &= node->mask.ip6[3]; + } +} + +static __init inline bool +horrible_match_v4(const struct horrible_allowedips_node *node, struct in_addr *ip) +{ + return (ip->s_addr & node->mask.ip) == node->ip.ip; +} + +static __init inline bool +horrible_match_v6(const struct horrible_allowedips_node *node, struct in6_addr *ip) +{ + return (ip->in6_u.u6_addr32[0] & node->mask.ip6[0]) == node->ip.ip6[0] && + (ip->in6_u.u6_addr32[1] & node->mask.ip6[1]) == node->ip.ip6[1] && + (ip->in6_u.u6_addr32[2] & node->mask.ip6[2]) == node->ip.ip6[2] && + (ip->in6_u.u6_addr32[3] & node->mask.ip6[3]) == node->ip.ip6[3]; +} + +static __init void +horrible_insert_ordered(struct horrible_allowedips *table, struct horrible_allowedips_node *node) +{ + struct horrible_allowedips_node *other = NULL, *where = NULL; + u8 my_cidr = horrible_mask_to_cidr(node->mask); + + hlist_for_each_entry(other, &table->head, table) { + if (other->ip_version == node->ip_version && + !memcmp(&other->mask, &node->mask, sizeof(union nf_inet_addr)) && + !memcmp(&other->ip, &node->ip, sizeof(union nf_inet_addr))) { + other->value = node->value; + kfree(node); + return; + } + } + hlist_for_each_entry(other, &table->head, table) { + where = other; + if (horrible_mask_to_cidr(other->mask) <= my_cidr) + break; + } + if (!other && !where) + hlist_add_head(&node->table, &table->head); + else if (!other) + hlist_add_behind(&node->table, &where->table); + else + hlist_add_before(&node->table, &where->table); +} + +static __init int +horrible_allowedips_insert_v4(struct horrible_allowedips *table, + struct in_addr *ip, u8 cidr, void *value) +{ + struct horrible_allowedips_node *node = kzalloc(sizeof(*node), GFP_KERNEL); + + if (unlikely(!node)) + return -ENOMEM; + node->ip.in = *ip; + node->mask = horrible_cidr_to_mask(cidr); + node->ip_version = 4; + node->value = value; + horrible_mask_self(node); + horrible_insert_ordered(table, node); + return 0; +} + +static __init int +horrible_allowedips_insert_v6(struct horrible_allowedips *table, + struct in6_addr *ip, u8 cidr, void *value) +{ + struct horrible_allowedips_node *node = kzalloc(sizeof(*node), GFP_KERNEL); + + if (unlikely(!node)) + return -ENOMEM; + node->ip.in6 = *ip; + node->mask = horrible_cidr_to_mask(cidr); + node->ip_version = 6; + node->value = value; + horrible_mask_self(node); + horrible_insert_ordered(table, node); + return 0; +} + +static __init void * +horrible_allowedips_lookup_v4(struct horrible_allowedips *table, struct in_addr *ip) +{ + struct horrible_allowedips_node *node; + + hlist_for_each_entry(node, &table->head, table) { + if (node->ip_version == 4 && horrible_match_v4(node, ip)) + return node->value; + } + return NULL; +} + +static __init void * +horrible_allowedips_lookup_v6(struct horrible_allowedips *table, struct in6_addr *ip) +{ + struct horrible_allowedips_node *node; + + hlist_for_each_entry(node, &table->head, table) { + if (node->ip_version == 6 && horrible_match_v6(node, ip)) + return node->value; + } + return NULL; +} + + +static __init void +horrible_allowedips_remove_by_value(struct horrible_allowedips *table, void *value) +{ + struct horrible_allowedips_node *node; + struct hlist_node *h; + + hlist_for_each_entry_safe(node, h, &table->head, table) { + if (node->value != value) + continue; + hlist_del(&node->table); + kfree(node); + } + +} + +static __init bool randomized_test(void) +{ + unsigned int i, j, k, mutate_amount, cidr; + u8 ip[16], mutate_mask[16], mutated[16]; + struct wg_peer **peers, *peer; + struct horrible_allowedips h; + DEFINE_MUTEX(mutex); + struct allowedips t; + bool ret = false; + + mutex_init(&mutex); + + wg_allowedips_init(&t); + horrible_allowedips_init(&h); + + peers = kcalloc(NUM_PEERS, sizeof(*peers), GFP_KERNEL); + if (unlikely(!peers)) { + pr_err("allowedips random self-test malloc: FAIL\n"); + goto free; + } + for (i = 0; i < NUM_PEERS; ++i) { + peers[i] = kzalloc(sizeof(*peers[i]), GFP_KERNEL); + if (unlikely(!peers[i])) { + pr_err("allowedips random self-test malloc: FAIL\n"); + goto free; + } + kref_init(&peers[i]->refcount); + INIT_LIST_HEAD(&peers[i]->allowedips_list); + } + + mutex_lock(&mutex); + + for (i = 0; i < NUM_RAND_ROUTES; ++i) { + get_random_bytes(ip, 4); + cidr = prandom_u32_max(32) + 1; + peer = peers[prandom_u32_max(NUM_PEERS)]; + if (wg_allowedips_insert_v4(&t, (struct in_addr *)ip, cidr, + peer, &mutex) < 0) { + pr_err("allowedips random self-test malloc: FAIL\n"); + goto free_locked; + } + if (horrible_allowedips_insert_v4(&h, (struct in_addr *)ip, + cidr, peer) < 0) { + pr_err("allowedips random self-test malloc: FAIL\n"); + goto free_locked; + } + for (j = 0; j < NUM_MUTATED_ROUTES; ++j) { + memcpy(mutated, ip, 4); + get_random_bytes(mutate_mask, 4); + mutate_amount = prandom_u32_max(32); + for (k = 0; k < mutate_amount / 8; ++k) + mutate_mask[k] = 0xff; + mutate_mask[k] = 0xff + << ((8 - (mutate_amount % 8)) % 8); + for (; k < 4; ++k) + mutate_mask[k] = 0; + for (k = 0; k < 4; ++k) + mutated[k] = (mutated[k] & mutate_mask[k]) | + (~mutate_mask[k] & + get_random_u8()); + cidr = prandom_u32_max(32) + 1; + peer = peers[prandom_u32_max(NUM_PEERS)]; + if (wg_allowedips_insert_v4(&t, + (struct in_addr *)mutated, + cidr, peer, &mutex) < 0) { + pr_err("allowedips random self-test malloc: FAIL\n"); + goto free_locked; + } + if (horrible_allowedips_insert_v4(&h, + (struct in_addr *)mutated, cidr, peer)) { + pr_err("allowedips random self-test malloc: FAIL\n"); + goto free_locked; + } + } + } + + for (i = 0; i < NUM_RAND_ROUTES; ++i) { + get_random_bytes(ip, 16); + cidr = prandom_u32_max(128) + 1; + peer = peers[prandom_u32_max(NUM_PEERS)]; + if (wg_allowedips_insert_v6(&t, (struct in6_addr *)ip, cidr, + peer, &mutex) < 0) { + pr_err("allowedips random self-test malloc: FAIL\n"); + goto free_locked; + } + if (horrible_allowedips_insert_v6(&h, (struct in6_addr *)ip, + cidr, peer) < 0) { + pr_err("allowedips random self-test malloc: FAIL\n"); + goto free_locked; + } + for (j = 0; j < NUM_MUTATED_ROUTES; ++j) { + memcpy(mutated, ip, 16); + get_random_bytes(mutate_mask, 16); + mutate_amount = prandom_u32_max(128); + for (k = 0; k < mutate_amount / 8; ++k) + mutate_mask[k] = 0xff; + mutate_mask[k] = 0xff + << ((8 - (mutate_amount % 8)) % 8); + for (; k < 4; ++k) + mutate_mask[k] = 0; + for (k = 0; k < 4; ++k) + mutated[k] = (mutated[k] & mutate_mask[k]) | + (~mutate_mask[k] & + get_random_u8()); + cidr = prandom_u32_max(128) + 1; + peer = peers[prandom_u32_max(NUM_PEERS)]; + if (wg_allowedips_insert_v6(&t, + (struct in6_addr *)mutated, + cidr, peer, &mutex) < 0) { + pr_err("allowedips random self-test malloc: FAIL\n"); + goto free_locked; + } + if (horrible_allowedips_insert_v6( + &h, (struct in6_addr *)mutated, cidr, + peer)) { + pr_err("allowedips random self-test malloc: FAIL\n"); + goto free_locked; + } + } + } + + mutex_unlock(&mutex); + + if (IS_ENABLED(DEBUG_PRINT_TRIE_GRAPHVIZ)) { + print_tree(t.root4, 32); + print_tree(t.root6, 128); + } + + for (j = 0;; ++j) { + for (i = 0; i < NUM_QUERIES; ++i) { + get_random_bytes(ip, 4); + if (lookup(t.root4, 32, ip) != horrible_allowedips_lookup_v4(&h, (struct in_addr *)ip)) { + horrible_allowedips_lookup_v4(&h, (struct in_addr *)ip); + pr_err("allowedips random v4 self-test: FAIL\n"); + goto free; + } + get_random_bytes(ip, 16); + if (lookup(t.root6, 128, ip) != horrible_allowedips_lookup_v6(&h, (struct in6_addr *)ip)) { + pr_err("allowedips random v6 self-test: FAIL\n"); + goto free; + } + } + if (j >= NUM_PEERS) + break; + mutex_lock(&mutex); + wg_allowedips_remove_by_peer(&t, peers[j], &mutex); + mutex_unlock(&mutex); + horrible_allowedips_remove_by_value(&h, peers[j]); + } + + if (t.root4 || t.root6) { + pr_err("allowedips random self-test removal: FAIL\n"); + goto free; + } + + ret = true; + +free: + mutex_lock(&mutex); +free_locked: + wg_allowedips_free(&t, &mutex); + mutex_unlock(&mutex); + horrible_allowedips_free(&h); + if (peers) { + for (i = 0; i < NUM_PEERS; ++i) + kfree(peers[i]); + } + kfree(peers); + return ret; +} + +static __init inline struct in_addr *ip4(u8 a, u8 b, u8 c, u8 d) +{ + static struct in_addr ip; + u8 *split = (u8 *)&ip; + + split[0] = a; + split[1] = b; + split[2] = c; + split[3] = d; + return &ip; +} + +static __init inline struct in6_addr *ip6(u32 a, u32 b, u32 c, u32 d) +{ + static struct in6_addr ip; + __be32 *split = (__be32 *)&ip; + + split[0] = cpu_to_be32(a); + split[1] = cpu_to_be32(b); + split[2] = cpu_to_be32(c); + split[3] = cpu_to_be32(d); + return &ip; +} + +static __init struct wg_peer *init_peer(void) +{ + struct wg_peer *peer = kzalloc(sizeof(*peer), GFP_KERNEL); + + if (!peer) + return NULL; + kref_init(&peer->refcount); + INIT_LIST_HEAD(&peer->allowedips_list); + return peer; +} + +#define insert(version, mem, ipa, ipb, ipc, ipd, cidr) \ + wg_allowedips_insert_v##version(&t, ip##version(ipa, ipb, ipc, ipd), \ + cidr, mem, &mutex) + +#define maybe_fail() do { \ + ++i; \ + if (!_s) { \ + pr_info("allowedips self-test %zu: FAIL\n", i); \ + success = false; \ + } \ + } while (0) + +#define test(version, mem, ipa, ipb, ipc, ipd) do { \ + bool _s = lookup(t.root##version, (version) == 4 ? 32 : 128, \ + ip##version(ipa, ipb, ipc, ipd)) == (mem); \ + maybe_fail(); \ + } while (0) + +#define test_negative(version, mem, ipa, ipb, ipc, ipd) do { \ + bool _s = lookup(t.root##version, (version) == 4 ? 32 : 128, \ + ip##version(ipa, ipb, ipc, ipd)) != (mem); \ + maybe_fail(); \ + } while (0) + +#define test_boolean(cond) do { \ + bool _s = (cond); \ + maybe_fail(); \ + } while (0) + +bool __init wg_allowedips_selftest(void) +{ + bool found_a = false, found_b = false, found_c = false, found_d = false, + found_e = false, found_other = false; + struct wg_peer *a = init_peer(), *b = init_peer(), *c = init_peer(), + *d = init_peer(), *e = init_peer(), *f = init_peer(), + *g = init_peer(), *h = init_peer(); + struct allowedips_node *iter_node; + bool success = false; + struct allowedips t; + DEFINE_MUTEX(mutex); + struct in6_addr ip; + size_t i = 0, count = 0; + __be64 part; + + mutex_init(&mutex); + mutex_lock(&mutex); + wg_allowedips_init(&t); + + if (!a || !b || !c || !d || !e || !f || !g || !h) { + pr_err("allowedips self-test malloc: FAIL\n"); + goto free; + } + + insert(4, a, 192, 168, 4, 0, 24); + insert(4, b, 192, 168, 4, 4, 32); + insert(4, c, 192, 168, 0, 0, 16); + insert(4, d, 192, 95, 5, 64, 27); + /* replaces previous entry, and maskself is required */ + insert(4, c, 192, 95, 5, 65, 27); + insert(6, d, 0x26075300, 0x60006b00, 0, 0xc05f0543, 128); + insert(6, c, 0x26075300, 0x60006b00, 0, 0, 64); + insert(4, e, 0, 0, 0, 0, 0); + insert(6, e, 0, 0, 0, 0, 0); + /* replaces previous entry */ + insert(6, f, 0, 0, 0, 0, 0); + insert(6, g, 0x24046800, 0, 0, 0, 32); + /* maskself is required */ + insert(6, h, 0x24046800, 0x40040800, 0xdeadbeef, 0xdeadbeef, 64); + insert(6, a, 0x24046800, 0x40040800, 0xdeadbeef, 0xdeadbeef, 128); + insert(6, c, 0x24446800, 0x40e40800, 0xdeaebeef, 0xdefbeef, 128); + insert(6, b, 0x24446800, 0xf0e40800, 0xeeaebeef, 0, 98); + insert(4, g, 64, 15, 112, 0, 20); + /* maskself is required */ + insert(4, h, 64, 15, 123, 211, 25); + insert(4, a, 10, 0, 0, 0, 25); + insert(4, b, 10, 0, 0, 128, 25); + insert(4, a, 10, 1, 0, 0, 30); + insert(4, b, 10, 1, 0, 4, 30); + insert(4, c, 10, 1, 0, 8, 29); + insert(4, d, 10, 1, 0, 16, 29); + + if (IS_ENABLED(DEBUG_PRINT_TRIE_GRAPHVIZ)) { + print_tree(t.root4, 32); + print_tree(t.root6, 128); + } + + success = true; + + test(4, a, 192, 168, 4, 20); + test(4, a, 192, 168, 4, 0); + test(4, b, 192, 168, 4, 4); + test(4, c, 192, 168, 200, 182); + test(4, c, 192, 95, 5, 68); + test(4, e, 192, 95, 5, 96); + test(6, d, 0x26075300, 0x60006b00, 0, 0xc05f0543); + test(6, c, 0x26075300, 0x60006b00, 0, 0xc02e01ee); + test(6, f, 0x26075300, 0x60006b01, 0, 0); + test(6, g, 0x24046800, 0x40040806, 0, 0x1006); + test(6, g, 0x24046800, 0x40040806, 0x1234, 0x5678); + test(6, f, 0x240467ff, 0x40040806, 0x1234, 0x5678); + test(6, f, 0x24046801, 0x40040806, 0x1234, 0x5678); + test(6, h, 0x24046800, 0x40040800, 0x1234, 0x5678); + test(6, h, 0x24046800, 0x40040800, 0, 0); + test(6, h, 0x24046800, 0x40040800, 0x10101010, 0x10101010); + test(6, a, 0x24046800, 0x40040800, 0xdeadbeef, 0xdeadbeef); + test(4, g, 64, 15, 116, 26); + test(4, g, 64, 15, 127, 3); + test(4, g, 64, 15, 123, 1); + test(4, h, 64, 15, 123, 128); + test(4, h, 64, 15, 123, 129); + test(4, a, 10, 0, 0, 52); + test(4, b, 10, 0, 0, 220); + test(4, a, 10, 1, 0, 2); + test(4, b, 10, 1, 0, 6); + test(4, c, 10, 1, 0, 10); + test(4, d, 10, 1, 0, 20); + + insert(4, a, 1, 0, 0, 0, 32); + insert(4, a, 64, 0, 0, 0, 32); + insert(4, a, 128, 0, 0, 0, 32); + insert(4, a, 192, 0, 0, 0, 32); + insert(4, a, 255, 0, 0, 0, 32); + wg_allowedips_remove_by_peer(&t, a, &mutex); + test_negative(4, a, 1, 0, 0, 0); + test_negative(4, a, 64, 0, 0, 0); + test_negative(4, a, 128, 0, 0, 0); + test_negative(4, a, 192, 0, 0, 0); + test_negative(4, a, 255, 0, 0, 0); + + wg_allowedips_free(&t, &mutex); + wg_allowedips_init(&t); + insert(4, a, 192, 168, 0, 0, 16); + insert(4, a, 192, 168, 0, 0, 24); + wg_allowedips_remove_by_peer(&t, a, &mutex); + test_negative(4, a, 192, 168, 0, 1); + + /* These will hit the WARN_ON(len >= MAX_ALLOWEDIPS_DEPTH) in free_node + * if something goes wrong. + */ + for (i = 0; i < 64; ++i) { + part = cpu_to_be64(~0LLU << i); + memset(&ip, 0xff, 8); + memcpy((u8 *)&ip + 8, &part, 8); + wg_allowedips_insert_v6(&t, &ip, 128, a, &mutex); + memcpy(&ip, &part, 8); + memset((u8 *)&ip + 8, 0, 8); + wg_allowedips_insert_v6(&t, &ip, 128, a, &mutex); + } + memset(&ip, 0, 16); + wg_allowedips_insert_v6(&t, &ip, 128, a, &mutex); + wg_allowedips_free(&t, &mutex); + + wg_allowedips_init(&t); + insert(4, a, 192, 95, 5, 93, 27); + insert(6, a, 0x26075300, 0x60006b00, 0, 0xc05f0543, 128); + insert(4, a, 10, 1, 0, 20, 29); + insert(6, a, 0x26075300, 0x6d8a6bf8, 0xdab1f1df, 0xc05f1523, 83); + insert(6, a, 0x26075300, 0x6d8a6bf8, 0xdab1f1df, 0xc05f1523, 21); + list_for_each_entry(iter_node, &a->allowedips_list, peer_list) { + u8 cidr, ip[16] __aligned(__alignof(u64)); + int family = wg_allowedips_read_node(iter_node, ip, &cidr); + + count++; + + if (cidr == 27 && family == AF_INET && + !memcmp(ip, ip4(192, 95, 5, 64), sizeof(struct in_addr))) + found_a = true; + else if (cidr == 128 && family == AF_INET6 && + !memcmp(ip, ip6(0x26075300, 0x60006b00, 0, 0xc05f0543), + sizeof(struct in6_addr))) + found_b = true; + else if (cidr == 29 && family == AF_INET && + !memcmp(ip, ip4(10, 1, 0, 16), sizeof(struct in_addr))) + found_c = true; + else if (cidr == 83 && family == AF_INET6 && + !memcmp(ip, ip6(0x26075300, 0x6d8a6bf8, 0xdab1e000, 0), + sizeof(struct in6_addr))) + found_d = true; + else if (cidr == 21 && family == AF_INET6 && + !memcmp(ip, ip6(0x26075000, 0, 0, 0), + sizeof(struct in6_addr))) + found_e = true; + else + found_other = true; + } + test_boolean(count == 5); + test_boolean(found_a); + test_boolean(found_b); + test_boolean(found_c); + test_boolean(found_d); + test_boolean(found_e); + test_boolean(!found_other); + + if (IS_ENABLED(DEBUG_RANDOM_TRIE) && success) + success = randomized_test(); + + if (success) + pr_info("allowedips self-tests: pass\n"); + +free: + wg_allowedips_free(&t, &mutex); + kfree(a); + kfree(b); + kfree(c); + kfree(d); + kfree(e); + kfree(f); + kfree(g); + kfree(h); + mutex_unlock(&mutex); + + return success; +} + +#undef test_negative +#undef test +#undef remove +#undef insert +#undef init_peer + +#endif diff --git a/drivers/net/wireguard/selftest/counter.c b/drivers/net/wireguard/selftest/counter.c new file mode 100644 index 000000000..ec3c156bf --- /dev/null +++ b/drivers/net/wireguard/selftest/counter.c @@ -0,0 +1,111 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#ifdef DEBUG +bool __init wg_packet_counter_selftest(void) +{ + struct noise_replay_counter *counter; + unsigned int test_num = 0, i; + bool success = true; + + counter = kmalloc(sizeof(*counter), GFP_KERNEL); + if (unlikely(!counter)) { + pr_err("nonce counter self-test malloc: FAIL\n"); + return false; + } + +#define T_INIT do { \ + memset(counter, 0, sizeof(*counter)); \ + spin_lock_init(&counter->lock); \ + } while (0) +#define T_LIM (COUNTER_WINDOW_SIZE + 1) +#define T(n, v) do { \ + ++test_num; \ + if (counter_validate(counter, n) != (v)) { \ + pr_err("nonce counter self-test %u: FAIL\n", \ + test_num); \ + success = false; \ + } \ + } while (0) + + T_INIT; + /* 1 */ T(0, true); + /* 2 */ T(1, true); + /* 3 */ T(1, false); + /* 4 */ T(9, true); + /* 5 */ T(8, true); + /* 6 */ T(7, true); + /* 7 */ T(7, false); + /* 8 */ T(T_LIM, true); + /* 9 */ T(T_LIM - 1, true); + /* 10 */ T(T_LIM - 1, false); + /* 11 */ T(T_LIM - 2, true); + /* 12 */ T(2, true); + /* 13 */ T(2, false); + /* 14 */ T(T_LIM + 16, true); + /* 15 */ T(3, false); + /* 16 */ T(T_LIM + 16, false); + /* 17 */ T(T_LIM * 4, true); + /* 18 */ T(T_LIM * 4 - (T_LIM - 1), true); + /* 19 */ T(10, false); + /* 20 */ T(T_LIM * 4 - T_LIM, false); + /* 21 */ T(T_LIM * 4 - (T_LIM + 1), false); + /* 22 */ T(T_LIM * 4 - (T_LIM - 2), true); + /* 23 */ T(T_LIM * 4 + 1 - T_LIM, false); + /* 24 */ T(0, false); + /* 25 */ T(REJECT_AFTER_MESSAGES, false); + /* 26 */ T(REJECT_AFTER_MESSAGES - 1, true); + /* 27 */ T(REJECT_AFTER_MESSAGES, false); + /* 28 */ T(REJECT_AFTER_MESSAGES - 1, false); + /* 29 */ T(REJECT_AFTER_MESSAGES - 2, true); + /* 30 */ T(REJECT_AFTER_MESSAGES + 1, false); + /* 31 */ T(REJECT_AFTER_MESSAGES + 2, false); + /* 32 */ T(REJECT_AFTER_MESSAGES - 2, false); + /* 33 */ T(REJECT_AFTER_MESSAGES - 3, true); + /* 34 */ T(0, false); + + T_INIT; + for (i = 1; i <= COUNTER_WINDOW_SIZE; ++i) + T(i, true); + T(0, true); + T(0, false); + + T_INIT; + for (i = 2; i <= COUNTER_WINDOW_SIZE + 1; ++i) + T(i, true); + T(1, true); + T(0, false); + + T_INIT; + for (i = COUNTER_WINDOW_SIZE + 1; i-- > 0;) + T(i, true); + + T_INIT; + for (i = COUNTER_WINDOW_SIZE + 2; i-- > 1;) + T(i, true); + T(0, false); + + T_INIT; + for (i = COUNTER_WINDOW_SIZE + 1; i-- > 1;) + T(i, true); + T(COUNTER_WINDOW_SIZE + 1, true); + T(0, false); + + T_INIT; + for (i = COUNTER_WINDOW_SIZE + 1; i-- > 1;) + T(i, true); + T(0, true); + T(COUNTER_WINDOW_SIZE + 1, true); + +#undef T +#undef T_LIM +#undef T_INIT + + if (success) + pr_info("nonce counter self-tests: pass\n"); + kfree(counter); + return success; +} +#endif diff --git a/drivers/net/wireguard/selftest/ratelimiter.c b/drivers/net/wireguard/selftest/ratelimiter.c new file mode 100644 index 000000000..d4bb40a69 --- /dev/null +++ b/drivers/net/wireguard/selftest/ratelimiter.c @@ -0,0 +1,224 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#ifdef DEBUG + +#include <linux/jiffies.h> + +static const struct { + bool result; + unsigned int msec_to_sleep_before; +} expected_results[] __initconst = { + [0 ... PACKETS_BURSTABLE - 1] = { true, 0 }, + [PACKETS_BURSTABLE] = { false, 0 }, + [PACKETS_BURSTABLE + 1] = { true, MSEC_PER_SEC / PACKETS_PER_SECOND }, + [PACKETS_BURSTABLE + 2] = { false, 0 }, + [PACKETS_BURSTABLE + 3] = { true, (MSEC_PER_SEC / PACKETS_PER_SECOND) * 2 }, + [PACKETS_BURSTABLE + 4] = { true, 0 }, + [PACKETS_BURSTABLE + 5] = { false, 0 } +}; + +static __init unsigned int maximum_jiffies_at_index(int index) +{ + unsigned int total_msecs = 2 * MSEC_PER_SEC / PACKETS_PER_SECOND / 3; + int i; + + for (i = 0; i <= index; ++i) + total_msecs += expected_results[i].msec_to_sleep_before; + return msecs_to_jiffies(total_msecs); +} + +static __init int timings_test(struct sk_buff *skb4, struct iphdr *hdr4, + struct sk_buff *skb6, struct ipv6hdr *hdr6, + int *test) +{ + unsigned long loop_start_time; + int i; + + wg_ratelimiter_gc_entries(NULL); + rcu_barrier(); + loop_start_time = jiffies; + + for (i = 0; i < ARRAY_SIZE(expected_results); ++i) { + if (expected_results[i].msec_to_sleep_before) + msleep(expected_results[i].msec_to_sleep_before); + + if (time_is_before_jiffies(loop_start_time + + maximum_jiffies_at_index(i))) + return -ETIMEDOUT; + if (wg_ratelimiter_allow(skb4, &init_net) != + expected_results[i].result) + return -EXFULL; + ++(*test); + + hdr4->saddr = htonl(ntohl(hdr4->saddr) + i + 1); + if (time_is_before_jiffies(loop_start_time + + maximum_jiffies_at_index(i))) + return -ETIMEDOUT; + if (!wg_ratelimiter_allow(skb4, &init_net)) + return -EXFULL; + ++(*test); + + hdr4->saddr = htonl(ntohl(hdr4->saddr) - i - 1); + +#if IS_ENABLED(CONFIG_IPV6) + hdr6->saddr.in6_u.u6_addr32[2] = htonl(i); + hdr6->saddr.in6_u.u6_addr32[3] = htonl(i); + if (time_is_before_jiffies(loop_start_time + + maximum_jiffies_at_index(i))) + return -ETIMEDOUT; + if (wg_ratelimiter_allow(skb6, &init_net) != + expected_results[i].result) + return -EXFULL; + ++(*test); + + hdr6->saddr.in6_u.u6_addr32[0] = + htonl(ntohl(hdr6->saddr.in6_u.u6_addr32[0]) + i + 1); + if (time_is_before_jiffies(loop_start_time + + maximum_jiffies_at_index(i))) + return -ETIMEDOUT; + if (!wg_ratelimiter_allow(skb6, &init_net)) + return -EXFULL; + ++(*test); + + hdr6->saddr.in6_u.u6_addr32[0] = + htonl(ntohl(hdr6->saddr.in6_u.u6_addr32[0]) - i - 1); + + if (time_is_before_jiffies(loop_start_time + + maximum_jiffies_at_index(i))) + return -ETIMEDOUT; +#endif + } + return 0; +} + +static __init int capacity_test(struct sk_buff *skb4, struct iphdr *hdr4, + int *test) +{ + int i; + + wg_ratelimiter_gc_entries(NULL); + rcu_barrier(); + + if (atomic_read(&total_entries)) + return -EXFULL; + ++(*test); + + for (i = 0; i <= max_entries; ++i) { + hdr4->saddr = htonl(i); + if (wg_ratelimiter_allow(skb4, &init_net) != (i != max_entries)) + return -EXFULL; + ++(*test); + } + return 0; +} + +bool __init wg_ratelimiter_selftest(void) +{ + enum { TRIALS_BEFORE_GIVING_UP = 5000 }; + bool success = false; + int test = 0, trials; + struct sk_buff *skb4, *skb6 = NULL; + struct iphdr *hdr4; + struct ipv6hdr *hdr6 = NULL; + + if (IS_ENABLED(CONFIG_KASAN) || IS_ENABLED(CONFIG_UBSAN)) + return true; + + BUILD_BUG_ON(MSEC_PER_SEC % PACKETS_PER_SECOND != 0); + + if (wg_ratelimiter_init()) + goto out; + ++test; + if (wg_ratelimiter_init()) { + wg_ratelimiter_uninit(); + goto out; + } + ++test; + if (wg_ratelimiter_init()) { + wg_ratelimiter_uninit(); + wg_ratelimiter_uninit(); + goto out; + } + ++test; + + skb4 = alloc_skb(sizeof(struct iphdr), GFP_KERNEL); + if (unlikely(!skb4)) + goto err_nofree; + skb4->protocol = htons(ETH_P_IP); + hdr4 = (struct iphdr *)skb_put(skb4, sizeof(*hdr4)); + hdr4->saddr = htonl(8182); + skb_reset_network_header(skb4); + ++test; + +#if IS_ENABLED(CONFIG_IPV6) + skb6 = alloc_skb(sizeof(struct ipv6hdr), GFP_KERNEL); + if (unlikely(!skb6)) { + kfree_skb(skb4); + goto err_nofree; + } + skb6->protocol = htons(ETH_P_IPV6); + hdr6 = (struct ipv6hdr *)skb_put(skb6, sizeof(*hdr6)); + hdr6->saddr.in6_u.u6_addr32[0] = htonl(1212); + hdr6->saddr.in6_u.u6_addr32[1] = htonl(289188); + skb_reset_network_header(skb6); + ++test; +#endif + + for (trials = TRIALS_BEFORE_GIVING_UP; IS_ENABLED(DEBUG_RATELIMITER_TIMINGS);) { + int test_count = 0, ret; + + ret = timings_test(skb4, hdr4, skb6, hdr6, &test_count); + if (ret == -ETIMEDOUT) { + if (!trials--) { + test += test_count; + goto err; + } + continue; + } else if (ret < 0) { + test += test_count; + goto err; + } else { + test += test_count; + break; + } + } + + for (trials = TRIALS_BEFORE_GIVING_UP;;) { + int test_count = 0; + + if (capacity_test(skb4, hdr4, &test_count) < 0) { + if (!trials--) { + test += test_count; + goto err; + } + continue; + } + test += test_count; + break; + } + + success = true; + +err: + kfree_skb(skb4); +#if IS_ENABLED(CONFIG_IPV6) + kfree_skb(skb6); +#endif +err_nofree: + wg_ratelimiter_uninit(); + wg_ratelimiter_uninit(); + wg_ratelimiter_uninit(); + /* Uninit one extra time to check underflow detection. */ + wg_ratelimiter_uninit(); +out: + if (success) + pr_info("ratelimiter self-tests: pass\n"); + else + pr_err("ratelimiter self-test %d: FAIL\n", test); + + return success; +} +#endif diff --git a/drivers/net/wireguard/send.c b/drivers/net/wireguard/send.c new file mode 100644 index 000000000..0d48e0f4a --- /dev/null +++ b/drivers/net/wireguard/send.c @@ -0,0 +1,414 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#include "queueing.h" +#include "timers.h" +#include "device.h" +#include "peer.h" +#include "socket.h" +#include "messages.h" +#include "cookie.h" + +#include <linux/uio.h> +#include <linux/inetdevice.h> +#include <linux/socket.h> +#include <net/ip_tunnels.h> +#include <net/udp.h> +#include <net/sock.h> + +static void wg_packet_send_handshake_initiation(struct wg_peer *peer) +{ + struct message_handshake_initiation packet; + + if (!wg_birthdate_has_expired(atomic64_read(&peer->last_sent_handshake), + REKEY_TIMEOUT)) + return; /* This function is rate limited. */ + + atomic64_set(&peer->last_sent_handshake, ktime_get_coarse_boottime_ns()); + net_dbg_ratelimited("%s: Sending handshake initiation to peer %llu (%pISpfsc)\n", + peer->device->dev->name, peer->internal_id, + &peer->endpoint.addr); + + if (wg_noise_handshake_create_initiation(&packet, &peer->handshake)) { + wg_cookie_add_mac_to_packet(&packet, sizeof(packet), peer); + wg_timers_any_authenticated_packet_traversal(peer); + wg_timers_any_authenticated_packet_sent(peer); + atomic64_set(&peer->last_sent_handshake, + ktime_get_coarse_boottime_ns()); + wg_socket_send_buffer_to_peer(peer, &packet, sizeof(packet), + HANDSHAKE_DSCP); + wg_timers_handshake_initiated(peer); + } +} + +void wg_packet_handshake_send_worker(struct work_struct *work) +{ + struct wg_peer *peer = container_of(work, struct wg_peer, + transmit_handshake_work); + + wg_packet_send_handshake_initiation(peer); + wg_peer_put(peer); +} + +void wg_packet_send_queued_handshake_initiation(struct wg_peer *peer, + bool is_retry) +{ + if (!is_retry) + peer->timer_handshake_attempts = 0; + + rcu_read_lock_bh(); + /* We check last_sent_handshake here in addition to the actual function + * we're queueing up, so that we don't queue things if not strictly + * necessary: + */ + if (!wg_birthdate_has_expired(atomic64_read(&peer->last_sent_handshake), + REKEY_TIMEOUT) || + unlikely(READ_ONCE(peer->is_dead))) + goto out; + + wg_peer_get(peer); + /* Queues up calling packet_send_queued_handshakes(peer), where we do a + * peer_put(peer) after: + */ + if (!queue_work(peer->device->handshake_send_wq, + &peer->transmit_handshake_work)) + /* If the work was already queued, we want to drop the + * extra reference: + */ + wg_peer_put(peer); +out: + rcu_read_unlock_bh(); +} + +void wg_packet_send_handshake_response(struct wg_peer *peer) +{ + struct message_handshake_response packet; + + atomic64_set(&peer->last_sent_handshake, ktime_get_coarse_boottime_ns()); + net_dbg_ratelimited("%s: Sending handshake response to peer %llu (%pISpfsc)\n", + peer->device->dev->name, peer->internal_id, + &peer->endpoint.addr); + + if (wg_noise_handshake_create_response(&packet, &peer->handshake)) { + wg_cookie_add_mac_to_packet(&packet, sizeof(packet), peer); + if (wg_noise_handshake_begin_session(&peer->handshake, + &peer->keypairs)) { + wg_timers_session_derived(peer); + wg_timers_any_authenticated_packet_traversal(peer); + wg_timers_any_authenticated_packet_sent(peer); + atomic64_set(&peer->last_sent_handshake, + ktime_get_coarse_boottime_ns()); + wg_socket_send_buffer_to_peer(peer, &packet, + sizeof(packet), + HANDSHAKE_DSCP); + } + } +} + +void wg_packet_send_handshake_cookie(struct wg_device *wg, + struct sk_buff *initiating_skb, + __le32 sender_index) +{ + struct message_handshake_cookie packet; + + net_dbg_skb_ratelimited("%s: Sending cookie response for denied handshake message for %pISpfsc\n", + wg->dev->name, initiating_skb); + wg_cookie_message_create(&packet, initiating_skb, sender_index, + &wg->cookie_checker); + wg_socket_send_buffer_as_reply_to_skb(wg, initiating_skb, &packet, + sizeof(packet)); +} + +static void keep_key_fresh(struct wg_peer *peer) +{ + struct noise_keypair *keypair; + bool send; + + rcu_read_lock_bh(); + keypair = rcu_dereference_bh(peer->keypairs.current_keypair); + send = keypair && READ_ONCE(keypair->sending.is_valid) && + (atomic64_read(&keypair->sending_counter) > REKEY_AFTER_MESSAGES || + (keypair->i_am_the_initiator && + wg_birthdate_has_expired(keypair->sending.birthdate, REKEY_AFTER_TIME))); + rcu_read_unlock_bh(); + + if (unlikely(send)) + wg_packet_send_queued_handshake_initiation(peer, false); +} + +static unsigned int calculate_skb_padding(struct sk_buff *skb) +{ + unsigned int padded_size, last_unit = skb->len; + + if (unlikely(!PACKET_CB(skb)->mtu)) + return ALIGN(last_unit, MESSAGE_PADDING_MULTIPLE) - last_unit; + + /* We do this modulo business with the MTU, just in case the networking + * layer gives us a packet that's bigger than the MTU. In that case, we + * wouldn't want the final subtraction to overflow in the case of the + * padded_size being clamped. Fortunately, that's very rarely the case, + * so we optimize for that not happening. + */ + if (unlikely(last_unit > PACKET_CB(skb)->mtu)) + last_unit %= PACKET_CB(skb)->mtu; + + padded_size = min(PACKET_CB(skb)->mtu, + ALIGN(last_unit, MESSAGE_PADDING_MULTIPLE)); + return padded_size - last_unit; +} + +static bool encrypt_packet(struct sk_buff *skb, struct noise_keypair *keypair) +{ + unsigned int padding_len, plaintext_len, trailer_len; + struct scatterlist sg[MAX_SKB_FRAGS + 8]; + struct message_data *header; + struct sk_buff *trailer; + int num_frags; + + /* Force hash calculation before encryption so that flow analysis is + * consistent over the inner packet. + */ + skb_get_hash(skb); + + /* Calculate lengths. */ + padding_len = calculate_skb_padding(skb); + trailer_len = padding_len + noise_encrypted_len(0); + plaintext_len = skb->len + padding_len; + + /* Expand data section to have room for padding and auth tag. */ + num_frags = skb_cow_data(skb, trailer_len, &trailer); + if (unlikely(num_frags < 0 || num_frags > ARRAY_SIZE(sg))) + return false; + + /* Set the padding to zeros, and make sure it and the auth tag are part + * of the skb. + */ + memset(skb_tail_pointer(trailer), 0, padding_len); + + /* Expand head section to have room for our header and the network + * stack's headers. + */ + if (unlikely(skb_cow_head(skb, DATA_PACKET_HEAD_ROOM) < 0)) + return false; + + /* Finalize checksum calculation for the inner packet, if required. */ + if (unlikely(skb->ip_summed == CHECKSUM_PARTIAL && + skb_checksum_help(skb))) + return false; + + /* Only after checksumming can we safely add on the padding at the end + * and the header. + */ + skb_set_inner_network_header(skb, 0); + header = (struct message_data *)skb_push(skb, sizeof(*header)); + header->header.type = cpu_to_le32(MESSAGE_DATA); + header->key_idx = keypair->remote_index; + header->counter = cpu_to_le64(PACKET_CB(skb)->nonce); + pskb_put(skb, trailer, trailer_len); + + /* Now we can encrypt the scattergather segments */ + sg_init_table(sg, num_frags); + if (skb_to_sgvec(skb, sg, sizeof(struct message_data), + noise_encrypted_len(plaintext_len)) <= 0) + return false; + return chacha20poly1305_encrypt_sg_inplace(sg, plaintext_len, NULL, 0, + PACKET_CB(skb)->nonce, + keypair->sending.key); +} + +void wg_packet_send_keepalive(struct wg_peer *peer) +{ + struct sk_buff *skb; + + if (skb_queue_empty(&peer->staged_packet_queue)) { + skb = alloc_skb(DATA_PACKET_HEAD_ROOM + MESSAGE_MINIMUM_LENGTH, + GFP_ATOMIC); + if (unlikely(!skb)) + return; + skb_reserve(skb, DATA_PACKET_HEAD_ROOM); + skb->dev = peer->device->dev; + PACKET_CB(skb)->mtu = skb->dev->mtu; + skb_queue_tail(&peer->staged_packet_queue, skb); + net_dbg_ratelimited("%s: Sending keepalive packet to peer %llu (%pISpfsc)\n", + peer->device->dev->name, peer->internal_id, + &peer->endpoint.addr); + } + + wg_packet_send_staged_packets(peer); +} + +static void wg_packet_create_data_done(struct wg_peer *peer, struct sk_buff *first) +{ + struct sk_buff *skb, *next; + bool is_keepalive, data_sent = false; + + wg_timers_any_authenticated_packet_traversal(peer); + wg_timers_any_authenticated_packet_sent(peer); + skb_list_walk_safe(first, skb, next) { + is_keepalive = skb->len == message_data_len(0); + if (likely(!wg_socket_send_skb_to_peer(peer, skb, + PACKET_CB(skb)->ds) && !is_keepalive)) + data_sent = true; + } + + if (likely(data_sent)) + wg_timers_data_sent(peer); + + keep_key_fresh(peer); +} + +void wg_packet_tx_worker(struct work_struct *work) +{ + struct wg_peer *peer = container_of(work, struct wg_peer, transmit_packet_work); + struct noise_keypair *keypair; + enum packet_state state; + struct sk_buff *first; + + while ((first = wg_prev_queue_peek(&peer->tx_queue)) != NULL && + (state = atomic_read_acquire(&PACKET_CB(first)->state)) != + PACKET_STATE_UNCRYPTED) { + wg_prev_queue_drop_peeked(&peer->tx_queue); + keypair = PACKET_CB(first)->keypair; + + if (likely(state == PACKET_STATE_CRYPTED)) + wg_packet_create_data_done(peer, first); + else + kfree_skb_list(first); + + wg_noise_keypair_put(keypair, false); + wg_peer_put(peer); + if (need_resched()) + cond_resched(); + } +} + +void wg_packet_encrypt_worker(struct work_struct *work) +{ + struct crypt_queue *queue = container_of(work, struct multicore_worker, + work)->ptr; + struct sk_buff *first, *skb, *next; + + while ((first = ptr_ring_consume_bh(&queue->ring)) != NULL) { + enum packet_state state = PACKET_STATE_CRYPTED; + + skb_list_walk_safe(first, skb, next) { + if (likely(encrypt_packet(skb, + PACKET_CB(first)->keypair))) { + wg_reset_packet(skb, true); + } else { + state = PACKET_STATE_DEAD; + break; + } + } + wg_queue_enqueue_per_peer_tx(first, state); + if (need_resched()) + cond_resched(); + } +} + +static void wg_packet_create_data(struct wg_peer *peer, struct sk_buff *first) +{ + struct wg_device *wg = peer->device; + int ret = -EINVAL; + + rcu_read_lock_bh(); + if (unlikely(READ_ONCE(peer->is_dead))) + goto err; + + ret = wg_queue_enqueue_per_device_and_peer(&wg->encrypt_queue, &peer->tx_queue, first, + wg->packet_crypt_wq); + if (unlikely(ret == -EPIPE)) + wg_queue_enqueue_per_peer_tx(first, PACKET_STATE_DEAD); +err: + rcu_read_unlock_bh(); + if (likely(!ret || ret == -EPIPE)) + return; + wg_noise_keypair_put(PACKET_CB(first)->keypair, false); + wg_peer_put(peer); + kfree_skb_list(first); +} + +void wg_packet_purge_staged_packets(struct wg_peer *peer) +{ + spin_lock_bh(&peer->staged_packet_queue.lock); + DEV_STATS_ADD(peer->device->dev, tx_dropped, + peer->staged_packet_queue.qlen); + __skb_queue_purge(&peer->staged_packet_queue); + spin_unlock_bh(&peer->staged_packet_queue.lock); +} + +void wg_packet_send_staged_packets(struct wg_peer *peer) +{ + struct noise_keypair *keypair; + struct sk_buff_head packets; + struct sk_buff *skb; + + /* Steal the current queue into our local one. */ + __skb_queue_head_init(&packets); + spin_lock_bh(&peer->staged_packet_queue.lock); + skb_queue_splice_init(&peer->staged_packet_queue, &packets); + spin_unlock_bh(&peer->staged_packet_queue.lock); + if (unlikely(skb_queue_empty(&packets))) + return; + + /* First we make sure we have a valid reference to a valid key. */ + rcu_read_lock_bh(); + keypair = wg_noise_keypair_get( + rcu_dereference_bh(peer->keypairs.current_keypair)); + rcu_read_unlock_bh(); + if (unlikely(!keypair)) + goto out_nokey; + if (unlikely(!READ_ONCE(keypair->sending.is_valid))) + goto out_nokey; + if (unlikely(wg_birthdate_has_expired(keypair->sending.birthdate, + REJECT_AFTER_TIME))) + goto out_invalid; + + /* After we know we have a somewhat valid key, we now try to assign + * nonces to all of the packets in the queue. If we can't assign nonces + * for all of them, we just consider it a failure and wait for the next + * handshake. + */ + skb_queue_walk(&packets, skb) { + /* 0 for no outer TOS: no leak. TODO: at some later point, we + * might consider using flowi->tos as outer instead. + */ + PACKET_CB(skb)->ds = ip_tunnel_ecn_encap(0, ip_hdr(skb), skb); + PACKET_CB(skb)->nonce = + atomic64_inc_return(&keypair->sending_counter) - 1; + if (unlikely(PACKET_CB(skb)->nonce >= REJECT_AFTER_MESSAGES)) + goto out_invalid; + } + + packets.prev->next = NULL; + wg_peer_get(keypair->entry.peer); + PACKET_CB(packets.next)->keypair = keypair; + wg_packet_create_data(peer, packets.next); + return; + +out_invalid: + WRITE_ONCE(keypair->sending.is_valid, false); +out_nokey: + wg_noise_keypair_put(keypair, false); + + /* We orphan the packets if we're waiting on a handshake, so that they + * don't block a socket's pool. + */ + skb_queue_walk(&packets, skb) + skb_orphan(skb); + /* Then we put them back on the top of the queue. We're not too + * concerned about accidentally getting things a little out of order if + * packets are being added really fast, because this queue is for before + * packets can even be sent and it's small anyway. + */ + spin_lock_bh(&peer->staged_packet_queue.lock); + skb_queue_splice(&packets, &peer->staged_packet_queue); + spin_unlock_bh(&peer->staged_packet_queue.lock); + + /* If we're exiting because there's something wrong with the key, it + * means we should initiate a new handshake. + */ + wg_packet_send_queued_handshake_initiation(peer, false); +} diff --git a/drivers/net/wireguard/socket.c b/drivers/net/wireguard/socket.c new file mode 100644 index 000000000..0414d7a6c --- /dev/null +++ b/drivers/net/wireguard/socket.c @@ -0,0 +1,437 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#include "device.h" +#include "peer.h" +#include "socket.h" +#include "queueing.h" +#include "messages.h" + +#include <linux/ctype.h> +#include <linux/net.h> +#include <linux/if_vlan.h> +#include <linux/if_ether.h> +#include <linux/inetdevice.h> +#include <net/udp_tunnel.h> +#include <net/ipv6.h> + +static int send4(struct wg_device *wg, struct sk_buff *skb, + struct endpoint *endpoint, u8 ds, struct dst_cache *cache) +{ + struct flowi4 fl = { + .saddr = endpoint->src4.s_addr, + .daddr = endpoint->addr4.sin_addr.s_addr, + .fl4_dport = endpoint->addr4.sin_port, + .flowi4_mark = wg->fwmark, + .flowi4_proto = IPPROTO_UDP + }; + struct rtable *rt = NULL; + struct sock *sock; + int ret = 0; + + skb_mark_not_on_list(skb); + skb->dev = wg->dev; + skb->mark = wg->fwmark; + + rcu_read_lock_bh(); + sock = rcu_dereference_bh(wg->sock4); + + if (unlikely(!sock)) { + ret = -ENONET; + goto err; + } + + fl.fl4_sport = inet_sk(sock)->inet_sport; + + if (cache) + rt = dst_cache_get_ip4(cache, &fl.saddr); + + if (!rt) { + security_sk_classify_flow(sock, flowi4_to_flowi_common(&fl)); + if (unlikely(!inet_confirm_addr(sock_net(sock), NULL, 0, + fl.saddr, RT_SCOPE_HOST))) { + endpoint->src4.s_addr = 0; + endpoint->src_if4 = 0; + fl.saddr = 0; + if (cache) + dst_cache_reset(cache); + } + rt = ip_route_output_flow(sock_net(sock), &fl, sock); + if (unlikely(endpoint->src_if4 && ((IS_ERR(rt) && + PTR_ERR(rt) == -EINVAL) || (!IS_ERR(rt) && + rt->dst.dev->ifindex != endpoint->src_if4)))) { + endpoint->src4.s_addr = 0; + endpoint->src_if4 = 0; + fl.saddr = 0; + if (cache) + dst_cache_reset(cache); + if (!IS_ERR(rt)) + ip_rt_put(rt); + rt = ip_route_output_flow(sock_net(sock), &fl, sock); + } + if (IS_ERR(rt)) { + ret = PTR_ERR(rt); + net_dbg_ratelimited("%s: No route to %pISpfsc, error %d\n", + wg->dev->name, &endpoint->addr, ret); + goto err; + } + if (cache) + dst_cache_set_ip4(cache, &rt->dst, fl.saddr); + } + + skb->ignore_df = 1; + udp_tunnel_xmit_skb(rt, sock, skb, fl.saddr, fl.daddr, ds, + ip4_dst_hoplimit(&rt->dst), 0, fl.fl4_sport, + fl.fl4_dport, false, false); + goto out; + +err: + kfree_skb(skb); +out: + rcu_read_unlock_bh(); + return ret; +} + +static int send6(struct wg_device *wg, struct sk_buff *skb, + struct endpoint *endpoint, u8 ds, struct dst_cache *cache) +{ +#if IS_ENABLED(CONFIG_IPV6) + struct flowi6 fl = { + .saddr = endpoint->src6, + .daddr = endpoint->addr6.sin6_addr, + .fl6_dport = endpoint->addr6.sin6_port, + .flowi6_mark = wg->fwmark, + .flowi6_oif = endpoint->addr6.sin6_scope_id, + .flowi6_proto = IPPROTO_UDP + /* TODO: addr->sin6_flowinfo */ + }; + struct dst_entry *dst = NULL; + struct sock *sock; + int ret = 0; + + skb_mark_not_on_list(skb); + skb->dev = wg->dev; + skb->mark = wg->fwmark; + + rcu_read_lock_bh(); + sock = rcu_dereference_bh(wg->sock6); + + if (unlikely(!sock)) { + ret = -ENONET; + goto err; + } + + fl.fl6_sport = inet_sk(sock)->inet_sport; + + if (cache) + dst = dst_cache_get_ip6(cache, &fl.saddr); + + if (!dst) { + security_sk_classify_flow(sock, flowi6_to_flowi_common(&fl)); + if (unlikely(!ipv6_addr_any(&fl.saddr) && + !ipv6_chk_addr(sock_net(sock), &fl.saddr, NULL, 0))) { + endpoint->src6 = fl.saddr = in6addr_any; + if (cache) + dst_cache_reset(cache); + } + dst = ipv6_stub->ipv6_dst_lookup_flow(sock_net(sock), sock, &fl, + NULL); + if (IS_ERR(dst)) { + ret = PTR_ERR(dst); + net_dbg_ratelimited("%s: No route to %pISpfsc, error %d\n", + wg->dev->name, &endpoint->addr, ret); + goto err; + } + if (cache) + dst_cache_set_ip6(cache, dst, &fl.saddr); + } + + skb->ignore_df = 1; + udp_tunnel6_xmit_skb(dst, sock, skb, skb->dev, &fl.saddr, &fl.daddr, ds, + ip6_dst_hoplimit(dst), 0, fl.fl6_sport, + fl.fl6_dport, false); + goto out; + +err: + kfree_skb(skb); +out: + rcu_read_unlock_bh(); + return ret; +#else + kfree_skb(skb); + return -EAFNOSUPPORT; +#endif +} + +int wg_socket_send_skb_to_peer(struct wg_peer *peer, struct sk_buff *skb, u8 ds) +{ + size_t skb_len = skb->len; + int ret = -EAFNOSUPPORT; + + read_lock_bh(&peer->endpoint_lock); + if (peer->endpoint.addr.sa_family == AF_INET) + ret = send4(peer->device, skb, &peer->endpoint, ds, + &peer->endpoint_cache); + else if (peer->endpoint.addr.sa_family == AF_INET6) + ret = send6(peer->device, skb, &peer->endpoint, ds, + &peer->endpoint_cache); + else + dev_kfree_skb(skb); + if (likely(!ret)) + peer->tx_bytes += skb_len; + read_unlock_bh(&peer->endpoint_lock); + + return ret; +} + +int wg_socket_send_buffer_to_peer(struct wg_peer *peer, void *buffer, + size_t len, u8 ds) +{ + struct sk_buff *skb = alloc_skb(len + SKB_HEADER_LEN, GFP_ATOMIC); + + if (unlikely(!skb)) + return -ENOMEM; + + skb_reserve(skb, SKB_HEADER_LEN); + skb_set_inner_network_header(skb, 0); + skb_put_data(skb, buffer, len); + return wg_socket_send_skb_to_peer(peer, skb, ds); +} + +int wg_socket_send_buffer_as_reply_to_skb(struct wg_device *wg, + struct sk_buff *in_skb, void *buffer, + size_t len) +{ + int ret = 0; + struct sk_buff *skb; + struct endpoint endpoint; + + if (unlikely(!in_skb)) + return -EINVAL; + ret = wg_socket_endpoint_from_skb(&endpoint, in_skb); + if (unlikely(ret < 0)) + return ret; + + skb = alloc_skb(len + SKB_HEADER_LEN, GFP_ATOMIC); + if (unlikely(!skb)) + return -ENOMEM; + skb_reserve(skb, SKB_HEADER_LEN); + skb_set_inner_network_header(skb, 0); + skb_put_data(skb, buffer, len); + + if (endpoint.addr.sa_family == AF_INET) + ret = send4(wg, skb, &endpoint, 0, NULL); + else if (endpoint.addr.sa_family == AF_INET6) + ret = send6(wg, skb, &endpoint, 0, NULL); + /* No other possibilities if the endpoint is valid, which it is, + * as we checked above. + */ + + return ret; +} + +int wg_socket_endpoint_from_skb(struct endpoint *endpoint, + const struct sk_buff *skb) +{ + memset(endpoint, 0, sizeof(*endpoint)); + if (skb->protocol == htons(ETH_P_IP)) { + endpoint->addr4.sin_family = AF_INET; + endpoint->addr4.sin_port = udp_hdr(skb)->source; + endpoint->addr4.sin_addr.s_addr = ip_hdr(skb)->saddr; + endpoint->src4.s_addr = ip_hdr(skb)->daddr; + endpoint->src_if4 = skb->skb_iif; + } else if (IS_ENABLED(CONFIG_IPV6) && skb->protocol == htons(ETH_P_IPV6)) { + endpoint->addr6.sin6_family = AF_INET6; + endpoint->addr6.sin6_port = udp_hdr(skb)->source; + endpoint->addr6.sin6_addr = ipv6_hdr(skb)->saddr; + endpoint->addr6.sin6_scope_id = ipv6_iface_scope_id( + &ipv6_hdr(skb)->saddr, skb->skb_iif); + endpoint->src6 = ipv6_hdr(skb)->daddr; + } else { + return -EINVAL; + } + return 0; +} + +static bool endpoint_eq(const struct endpoint *a, const struct endpoint *b) +{ + return (a->addr.sa_family == AF_INET && b->addr.sa_family == AF_INET && + a->addr4.sin_port == b->addr4.sin_port && + a->addr4.sin_addr.s_addr == b->addr4.sin_addr.s_addr && + a->src4.s_addr == b->src4.s_addr && a->src_if4 == b->src_if4) || + (a->addr.sa_family == AF_INET6 && + b->addr.sa_family == AF_INET6 && + a->addr6.sin6_port == b->addr6.sin6_port && + ipv6_addr_equal(&a->addr6.sin6_addr, &b->addr6.sin6_addr) && + a->addr6.sin6_scope_id == b->addr6.sin6_scope_id && + ipv6_addr_equal(&a->src6, &b->src6)) || + unlikely(!a->addr.sa_family && !b->addr.sa_family); +} + +void wg_socket_set_peer_endpoint(struct wg_peer *peer, + const struct endpoint *endpoint) +{ + /* First we check unlocked, in order to optimize, since it's pretty rare + * that an endpoint will change. If we happen to be mid-write, and two + * CPUs wind up writing the same thing or something slightly different, + * it doesn't really matter much either. + */ + if (endpoint_eq(endpoint, &peer->endpoint)) + return; + write_lock_bh(&peer->endpoint_lock); + if (endpoint->addr.sa_family == AF_INET) { + peer->endpoint.addr4 = endpoint->addr4; + peer->endpoint.src4 = endpoint->src4; + peer->endpoint.src_if4 = endpoint->src_if4; + } else if (IS_ENABLED(CONFIG_IPV6) && endpoint->addr.sa_family == AF_INET6) { + peer->endpoint.addr6 = endpoint->addr6; + peer->endpoint.src6 = endpoint->src6; + } else { + goto out; + } + dst_cache_reset(&peer->endpoint_cache); +out: + write_unlock_bh(&peer->endpoint_lock); +} + +void wg_socket_set_peer_endpoint_from_skb(struct wg_peer *peer, + const struct sk_buff *skb) +{ + struct endpoint endpoint; + + if (!wg_socket_endpoint_from_skb(&endpoint, skb)) + wg_socket_set_peer_endpoint(peer, &endpoint); +} + +void wg_socket_clear_peer_endpoint_src(struct wg_peer *peer) +{ + write_lock_bh(&peer->endpoint_lock); + memset(&peer->endpoint.src6, 0, sizeof(peer->endpoint.src6)); + dst_cache_reset_now(&peer->endpoint_cache); + write_unlock_bh(&peer->endpoint_lock); +} + +static int wg_receive(struct sock *sk, struct sk_buff *skb) +{ + struct wg_device *wg; + + if (unlikely(!sk)) + goto err; + wg = sk->sk_user_data; + if (unlikely(!wg)) + goto err; + skb_mark_not_on_list(skb); + wg_packet_receive(wg, skb); + return 0; + +err: + kfree_skb(skb); + return 0; +} + +static void sock_free(struct sock *sock) +{ + if (unlikely(!sock)) + return; + sk_clear_memalloc(sock); + udp_tunnel_sock_release(sock->sk_socket); +} + +static void set_sock_opts(struct socket *sock) +{ + sock->sk->sk_allocation = GFP_ATOMIC; + sock->sk->sk_sndbuf = INT_MAX; + sk_set_memalloc(sock->sk); +} + +int wg_socket_init(struct wg_device *wg, u16 port) +{ + struct net *net; + int ret; + struct udp_tunnel_sock_cfg cfg = { + .sk_user_data = wg, + .encap_type = 1, + .encap_rcv = wg_receive + }; + struct socket *new4 = NULL, *new6 = NULL; + struct udp_port_cfg port4 = { + .family = AF_INET, + .local_ip.s_addr = htonl(INADDR_ANY), + .local_udp_port = htons(port), + .use_udp_checksums = true + }; +#if IS_ENABLED(CONFIG_IPV6) + int retries = 0; + struct udp_port_cfg port6 = { + .family = AF_INET6, + .local_ip6 = IN6ADDR_ANY_INIT, + .use_udp6_tx_checksums = true, + .use_udp6_rx_checksums = true, + .ipv6_v6only = true + }; +#endif + + rcu_read_lock(); + net = rcu_dereference(wg->creating_net); + net = net ? maybe_get_net(net) : NULL; + rcu_read_unlock(); + if (unlikely(!net)) + return -ENONET; + +#if IS_ENABLED(CONFIG_IPV6) +retry: +#endif + + ret = udp_sock_create(net, &port4, &new4); + if (ret < 0) { + pr_err("%s: Could not create IPv4 socket\n", wg->dev->name); + goto out; + } + set_sock_opts(new4); + setup_udp_tunnel_sock(net, new4, &cfg); + +#if IS_ENABLED(CONFIG_IPV6) + if (ipv6_mod_enabled()) { + port6.local_udp_port = inet_sk(new4->sk)->inet_sport; + ret = udp_sock_create(net, &port6, &new6); + if (ret < 0) { + udp_tunnel_sock_release(new4); + if (ret == -EADDRINUSE && !port && retries++ < 100) + goto retry; + pr_err("%s: Could not create IPv6 socket\n", + wg->dev->name); + goto out; + } + set_sock_opts(new6); + setup_udp_tunnel_sock(net, new6, &cfg); + } +#endif + + wg_socket_reinit(wg, new4->sk, new6 ? new6->sk : NULL); + ret = 0; +out: + put_net(net); + return ret; +} + +void wg_socket_reinit(struct wg_device *wg, struct sock *new4, + struct sock *new6) +{ + struct sock *old4, *old6; + + mutex_lock(&wg->socket_update_lock); + old4 = rcu_dereference_protected(wg->sock4, + lockdep_is_held(&wg->socket_update_lock)); + old6 = rcu_dereference_protected(wg->sock6, + lockdep_is_held(&wg->socket_update_lock)); + rcu_assign_pointer(wg->sock4, new4); + rcu_assign_pointer(wg->sock6, new6); + if (new4) + wg->incoming_port = ntohs(inet_sk(new4)->inet_sport); + mutex_unlock(&wg->socket_update_lock); + synchronize_net(); + sock_free(old4); + sock_free(old6); +} diff --git a/drivers/net/wireguard/socket.h b/drivers/net/wireguard/socket.h new file mode 100644 index 000000000..bab5848ef --- /dev/null +++ b/drivers/net/wireguard/socket.h @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#ifndef _WG_SOCKET_H +#define _WG_SOCKET_H + +#include <linux/netdevice.h> +#include <linux/udp.h> +#include <linux/if_vlan.h> +#include <linux/if_ether.h> + +int wg_socket_init(struct wg_device *wg, u16 port); +void wg_socket_reinit(struct wg_device *wg, struct sock *new4, + struct sock *new6); +int wg_socket_send_buffer_to_peer(struct wg_peer *peer, void *data, + size_t len, u8 ds); +int wg_socket_send_skb_to_peer(struct wg_peer *peer, struct sk_buff *skb, + u8 ds); +int wg_socket_send_buffer_as_reply_to_skb(struct wg_device *wg, + struct sk_buff *in_skb, + void *out_buffer, size_t len); + +int wg_socket_endpoint_from_skb(struct endpoint *endpoint, + const struct sk_buff *skb); +void wg_socket_set_peer_endpoint(struct wg_peer *peer, + const struct endpoint *endpoint); +void wg_socket_set_peer_endpoint_from_skb(struct wg_peer *peer, + const struct sk_buff *skb); +void wg_socket_clear_peer_endpoint_src(struct wg_peer *peer); + +#if defined(CONFIG_DYNAMIC_DEBUG) || defined(DEBUG) +#define net_dbg_skb_ratelimited(fmt, dev, skb, ...) do { \ + struct endpoint __endpoint; \ + wg_socket_endpoint_from_skb(&__endpoint, skb); \ + net_dbg_ratelimited(fmt, dev, &__endpoint.addr, \ + ##__VA_ARGS__); \ + } while (0) +#else +#define net_dbg_skb_ratelimited(fmt, skb, ...) +#endif + +#endif /* _WG_SOCKET_H */ diff --git a/drivers/net/wireguard/timers.c b/drivers/net/wireguard/timers.c new file mode 100644 index 000000000..91f5d6d2d --- /dev/null +++ b/drivers/net/wireguard/timers.c @@ -0,0 +1,243 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#include "timers.h" +#include "device.h" +#include "peer.h" +#include "queueing.h" +#include "socket.h" + +/* + * - Timer for retransmitting the handshake if we don't hear back after + * `REKEY_TIMEOUT + jitter` ms. + * + * - Timer for sending empty packet if we have received a packet but after have + * not sent one for `KEEPALIVE_TIMEOUT` ms. + * + * - Timer for initiating new handshake if we have sent a packet but after have + * not received one (even empty) for `(KEEPALIVE_TIMEOUT + REKEY_TIMEOUT) + + * jitter` ms. + * + * - Timer for zeroing out all ephemeral keys after `(REJECT_AFTER_TIME * 3)` ms + * if no new keys have been received. + * + * - Timer for, if enabled, sending an empty authenticated packet every user- + * specified seconds. + */ + +static inline void mod_peer_timer(struct wg_peer *peer, + struct timer_list *timer, + unsigned long expires) +{ + rcu_read_lock_bh(); + if (likely(netif_running(peer->device->dev) && + !READ_ONCE(peer->is_dead))) + mod_timer(timer, expires); + rcu_read_unlock_bh(); +} + +static void wg_expired_retransmit_handshake(struct timer_list *timer) +{ + struct wg_peer *peer = from_timer(peer, timer, + timer_retransmit_handshake); + + if (peer->timer_handshake_attempts > MAX_TIMER_HANDSHAKES) { + pr_debug("%s: Handshake for peer %llu (%pISpfsc) did not complete after %d attempts, giving up\n", + peer->device->dev->name, peer->internal_id, + &peer->endpoint.addr, (int)MAX_TIMER_HANDSHAKES + 2); + + del_timer(&peer->timer_send_keepalive); + /* We drop all packets without a keypair and don't try again, + * if we try unsuccessfully for too long to make a handshake. + */ + wg_packet_purge_staged_packets(peer); + + /* We set a timer for destroying any residue that might be left + * of a partial exchange. + */ + if (!timer_pending(&peer->timer_zero_key_material)) + mod_peer_timer(peer, &peer->timer_zero_key_material, + jiffies + REJECT_AFTER_TIME * 3 * HZ); + } else { + ++peer->timer_handshake_attempts; + pr_debug("%s: Handshake for peer %llu (%pISpfsc) did not complete after %d seconds, retrying (try %d)\n", + peer->device->dev->name, peer->internal_id, + &peer->endpoint.addr, (int)REKEY_TIMEOUT, + peer->timer_handshake_attempts + 1); + + /* We clear the endpoint address src address, in case this is + * the cause of trouble. + */ + wg_socket_clear_peer_endpoint_src(peer); + + wg_packet_send_queued_handshake_initiation(peer, true); + } +} + +static void wg_expired_send_keepalive(struct timer_list *timer) +{ + struct wg_peer *peer = from_timer(peer, timer, timer_send_keepalive); + + wg_packet_send_keepalive(peer); + if (peer->timer_need_another_keepalive) { + peer->timer_need_another_keepalive = false; + mod_peer_timer(peer, &peer->timer_send_keepalive, + jiffies + KEEPALIVE_TIMEOUT * HZ); + } +} + +static void wg_expired_new_handshake(struct timer_list *timer) +{ + struct wg_peer *peer = from_timer(peer, timer, timer_new_handshake); + + pr_debug("%s: Retrying handshake with peer %llu (%pISpfsc) because we stopped hearing back after %d seconds\n", + peer->device->dev->name, peer->internal_id, + &peer->endpoint.addr, (int)(KEEPALIVE_TIMEOUT + REKEY_TIMEOUT)); + /* We clear the endpoint address src address, in case this is the cause + * of trouble. + */ + wg_socket_clear_peer_endpoint_src(peer); + wg_packet_send_queued_handshake_initiation(peer, false); +} + +static void wg_expired_zero_key_material(struct timer_list *timer) +{ + struct wg_peer *peer = from_timer(peer, timer, timer_zero_key_material); + + rcu_read_lock_bh(); + if (!READ_ONCE(peer->is_dead)) { + wg_peer_get(peer); + if (!queue_work(peer->device->handshake_send_wq, + &peer->clear_peer_work)) + /* If the work was already on the queue, we want to drop + * the extra reference. + */ + wg_peer_put(peer); + } + rcu_read_unlock_bh(); +} + +static void wg_queued_expired_zero_key_material(struct work_struct *work) +{ + struct wg_peer *peer = container_of(work, struct wg_peer, + clear_peer_work); + + pr_debug("%s: Zeroing out all keys for peer %llu (%pISpfsc), since we haven't received a new one in %d seconds\n", + peer->device->dev->name, peer->internal_id, + &peer->endpoint.addr, (int)REJECT_AFTER_TIME * 3); + wg_noise_handshake_clear(&peer->handshake); + wg_noise_keypairs_clear(&peer->keypairs); + wg_peer_put(peer); +} + +static void wg_expired_send_persistent_keepalive(struct timer_list *timer) +{ + struct wg_peer *peer = from_timer(peer, timer, + timer_persistent_keepalive); + + if (likely(peer->persistent_keepalive_interval)) + wg_packet_send_keepalive(peer); +} + +/* Should be called after an authenticated data packet is sent. */ +void wg_timers_data_sent(struct wg_peer *peer) +{ + if (!timer_pending(&peer->timer_new_handshake)) + mod_peer_timer(peer, &peer->timer_new_handshake, + jiffies + (KEEPALIVE_TIMEOUT + REKEY_TIMEOUT) * HZ + + prandom_u32_max(REKEY_TIMEOUT_JITTER_MAX_JIFFIES)); +} + +/* Should be called after an authenticated data packet is received. */ +void wg_timers_data_received(struct wg_peer *peer) +{ + if (likely(netif_running(peer->device->dev))) { + if (!timer_pending(&peer->timer_send_keepalive)) + mod_peer_timer(peer, &peer->timer_send_keepalive, + jiffies + KEEPALIVE_TIMEOUT * HZ); + else + peer->timer_need_another_keepalive = true; + } +} + +/* Should be called after any type of authenticated packet is sent, whether + * keepalive, data, or handshake. + */ +void wg_timers_any_authenticated_packet_sent(struct wg_peer *peer) +{ + del_timer(&peer->timer_send_keepalive); +} + +/* Should be called after any type of authenticated packet is received, whether + * keepalive, data, or handshake. + */ +void wg_timers_any_authenticated_packet_received(struct wg_peer *peer) +{ + del_timer(&peer->timer_new_handshake); +} + +/* Should be called after a handshake initiation message is sent. */ +void wg_timers_handshake_initiated(struct wg_peer *peer) +{ + mod_peer_timer(peer, &peer->timer_retransmit_handshake, + jiffies + REKEY_TIMEOUT * HZ + + prandom_u32_max(REKEY_TIMEOUT_JITTER_MAX_JIFFIES)); +} + +/* Should be called after a handshake response message is received and processed + * or when getting key confirmation via the first data message. + */ +void wg_timers_handshake_complete(struct wg_peer *peer) +{ + del_timer(&peer->timer_retransmit_handshake); + peer->timer_handshake_attempts = 0; + peer->sent_lastminute_handshake = false; + ktime_get_real_ts64(&peer->walltime_last_handshake); +} + +/* Should be called after an ephemeral key is created, which is before sending a + * handshake response or after receiving a handshake response. + */ +void wg_timers_session_derived(struct wg_peer *peer) +{ + mod_peer_timer(peer, &peer->timer_zero_key_material, + jiffies + REJECT_AFTER_TIME * 3 * HZ); +} + +/* Should be called before a packet with authentication, whether + * keepalive, data, or handshakem is sent, or after one is received. + */ +void wg_timers_any_authenticated_packet_traversal(struct wg_peer *peer) +{ + if (peer->persistent_keepalive_interval) + mod_peer_timer(peer, &peer->timer_persistent_keepalive, + jiffies + peer->persistent_keepalive_interval * HZ); +} + +void wg_timers_init(struct wg_peer *peer) +{ + timer_setup(&peer->timer_retransmit_handshake, + wg_expired_retransmit_handshake, 0); + timer_setup(&peer->timer_send_keepalive, wg_expired_send_keepalive, 0); + timer_setup(&peer->timer_new_handshake, wg_expired_new_handshake, 0); + timer_setup(&peer->timer_zero_key_material, + wg_expired_zero_key_material, 0); + timer_setup(&peer->timer_persistent_keepalive, + wg_expired_send_persistent_keepalive, 0); + INIT_WORK(&peer->clear_peer_work, wg_queued_expired_zero_key_material); + peer->timer_handshake_attempts = 0; + peer->sent_lastminute_handshake = false; + peer->timer_need_another_keepalive = false; +} + +void wg_timers_stop(struct wg_peer *peer) +{ + del_timer_sync(&peer->timer_retransmit_handshake); + del_timer_sync(&peer->timer_send_keepalive); + del_timer_sync(&peer->timer_new_handshake); + del_timer_sync(&peer->timer_zero_key_material); + del_timer_sync(&peer->timer_persistent_keepalive); + flush_work(&peer->clear_peer_work); +} diff --git a/drivers/net/wireguard/timers.h b/drivers/net/wireguard/timers.h new file mode 100644 index 000000000..f0653dcb1 --- /dev/null +++ b/drivers/net/wireguard/timers.h @@ -0,0 +1,31 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#ifndef _WG_TIMERS_H +#define _WG_TIMERS_H + +#include <linux/ktime.h> + +struct wg_peer; + +void wg_timers_init(struct wg_peer *peer); +void wg_timers_stop(struct wg_peer *peer); +void wg_timers_data_sent(struct wg_peer *peer); +void wg_timers_data_received(struct wg_peer *peer); +void wg_timers_any_authenticated_packet_sent(struct wg_peer *peer); +void wg_timers_any_authenticated_packet_received(struct wg_peer *peer); +void wg_timers_handshake_initiated(struct wg_peer *peer); +void wg_timers_handshake_complete(struct wg_peer *peer); +void wg_timers_session_derived(struct wg_peer *peer); +void wg_timers_any_authenticated_packet_traversal(struct wg_peer *peer); + +static inline bool wg_birthdate_has_expired(u64 birthday_nanoseconds, + u64 expiration_seconds) +{ + return (s64)(birthday_nanoseconds + expiration_seconds * NSEC_PER_SEC) + <= (s64)ktime_get_coarse_boottime_ns(); +} + +#endif /* _WG_TIMERS_H */ diff --git a/drivers/net/wireguard/version.h b/drivers/net/wireguard/version.h new file mode 100644 index 000000000..a1a269a11 --- /dev/null +++ b/drivers/net/wireguard/version.h @@ -0,0 +1 @@ +#define WIREGUARD_VERSION "1.0.0" |