From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- net/netfilter/nf_conntrack_bpf.c | 510 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 510 insertions(+) create mode 100644 net/netfilter/nf_conntrack_bpf.c (limited to 'net/netfilter/nf_conntrack_bpf.c') diff --git a/net/netfilter/nf_conntrack_bpf.c b/net/netfilter/nf_conntrack_bpf.c new file mode 100644 index 0000000000..b21799d468 --- /dev/null +++ b/net/netfilter/nf_conntrack_bpf.c @@ -0,0 +1,510 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Unstable Conntrack Helpers for XDP and TC-BPF hook + * + * These are called from the XDP and SCHED_CLS BPF programs. Note that it is + * allowed to break compatibility for these functions since the interface they + * are exposed through to BPF programs is explicitly unstable. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* bpf_ct_opts - Options for CT lookup helpers + * + * Members: + * @netns_id - Specify the network namespace for lookup + * Values: + * BPF_F_CURRENT_NETNS (-1) + * Use namespace associated with ctx (xdp_md, __sk_buff) + * [0, S32_MAX] + * Network Namespace ID + * @error - Out parameter, set for any errors encountered + * Values: + * -EINVAL - Passed NULL for bpf_tuple pointer + * -EINVAL - opts->reserved is not 0 + * -EINVAL - netns_id is less than -1 + * -EINVAL - opts__sz isn't NF_BPF_CT_OPTS_SZ (12) + * -EPROTO - l4proto isn't one of IPPROTO_TCP or IPPROTO_UDP + * -ENONET - No network namespace found for netns_id + * -ENOENT - Conntrack lookup could not find entry for tuple + * -EAFNOSUPPORT - tuple__sz isn't one of sizeof(tuple->ipv4) + * or sizeof(tuple->ipv6) + * @l4proto - Layer 4 protocol + * Values: + * IPPROTO_TCP, IPPROTO_UDP + * @dir: - connection tracking tuple direction. + * @reserved - Reserved member, will be reused for more options in future + * Values: + * 0 + */ +struct bpf_ct_opts { + s32 netns_id; + s32 error; + u8 l4proto; + u8 dir; + u8 reserved[2]; +}; + +enum { + NF_BPF_CT_OPTS_SZ = 12, +}; + +static int bpf_nf_ct_tuple_parse(struct bpf_sock_tuple *bpf_tuple, + u32 tuple_len, u8 protonum, u8 dir, + struct nf_conntrack_tuple *tuple) +{ + union nf_inet_addr *src = dir ? &tuple->dst.u3 : &tuple->src.u3; + union nf_inet_addr *dst = dir ? &tuple->src.u3 : &tuple->dst.u3; + union nf_conntrack_man_proto *sport = dir ? (void *)&tuple->dst.u + : &tuple->src.u; + union nf_conntrack_man_proto *dport = dir ? &tuple->src.u + : (void *)&tuple->dst.u; + + if (unlikely(protonum != IPPROTO_TCP && protonum != IPPROTO_UDP)) + return -EPROTO; + + memset(tuple, 0, sizeof(*tuple)); + + switch (tuple_len) { + case sizeof(bpf_tuple->ipv4): + tuple->src.l3num = AF_INET; + src->ip = bpf_tuple->ipv4.saddr; + sport->tcp.port = bpf_tuple->ipv4.sport; + dst->ip = bpf_tuple->ipv4.daddr; + dport->tcp.port = bpf_tuple->ipv4.dport; + break; + case sizeof(bpf_tuple->ipv6): + tuple->src.l3num = AF_INET6; + memcpy(src->ip6, bpf_tuple->ipv6.saddr, sizeof(bpf_tuple->ipv6.saddr)); + sport->tcp.port = bpf_tuple->ipv6.sport; + memcpy(dst->ip6, bpf_tuple->ipv6.daddr, sizeof(bpf_tuple->ipv6.daddr)); + dport->tcp.port = bpf_tuple->ipv6.dport; + break; + default: + return -EAFNOSUPPORT; + } + tuple->dst.protonum = protonum; + tuple->dst.dir = dir; + + return 0; +} + +static struct nf_conn * +__bpf_nf_ct_alloc_entry(struct net *net, struct bpf_sock_tuple *bpf_tuple, + u32 tuple_len, struct bpf_ct_opts *opts, u32 opts_len, + u32 timeout) +{ + struct nf_conntrack_tuple otuple, rtuple; + struct nf_conn *ct; + int err; + + if (!opts || !bpf_tuple || opts->reserved[0] || opts->reserved[1] || + opts_len != NF_BPF_CT_OPTS_SZ) + return ERR_PTR(-EINVAL); + + if (unlikely(opts->netns_id < BPF_F_CURRENT_NETNS)) + return ERR_PTR(-EINVAL); + + err = bpf_nf_ct_tuple_parse(bpf_tuple, tuple_len, opts->l4proto, + IP_CT_DIR_ORIGINAL, &otuple); + if (err < 0) + return ERR_PTR(err); + + err = bpf_nf_ct_tuple_parse(bpf_tuple, tuple_len, opts->l4proto, + IP_CT_DIR_REPLY, &rtuple); + if (err < 0) + return ERR_PTR(err); + + if (opts->netns_id >= 0) { + net = get_net_ns_by_id(net, opts->netns_id); + if (unlikely(!net)) + return ERR_PTR(-ENONET); + } + + ct = nf_conntrack_alloc(net, &nf_ct_zone_dflt, &otuple, &rtuple, + GFP_ATOMIC); + if (IS_ERR(ct)) + goto out; + + memset(&ct->proto, 0, sizeof(ct->proto)); + __nf_ct_set_timeout(ct, timeout * HZ); + +out: + if (opts->netns_id >= 0) + put_net(net); + + return ct; +} + +static struct nf_conn *__bpf_nf_ct_lookup(struct net *net, + struct bpf_sock_tuple *bpf_tuple, + u32 tuple_len, struct bpf_ct_opts *opts, + u32 opts_len) +{ + struct nf_conntrack_tuple_hash *hash; + struct nf_conntrack_tuple tuple; + struct nf_conn *ct; + int err; + + if (!opts || !bpf_tuple || opts->reserved[0] || opts->reserved[1] || + opts_len != NF_BPF_CT_OPTS_SZ) + return ERR_PTR(-EINVAL); + if (unlikely(opts->l4proto != IPPROTO_TCP && opts->l4proto != IPPROTO_UDP)) + return ERR_PTR(-EPROTO); + if (unlikely(opts->netns_id < BPF_F_CURRENT_NETNS)) + return ERR_PTR(-EINVAL); + + err = bpf_nf_ct_tuple_parse(bpf_tuple, tuple_len, opts->l4proto, + IP_CT_DIR_ORIGINAL, &tuple); + if (err < 0) + return ERR_PTR(err); + + if (opts->netns_id >= 0) { + net = get_net_ns_by_id(net, opts->netns_id); + if (unlikely(!net)) + return ERR_PTR(-ENONET); + } + + hash = nf_conntrack_find_get(net, &nf_ct_zone_dflt, &tuple); + if (opts->netns_id >= 0) + put_net(net); + if (!hash) + return ERR_PTR(-ENOENT); + + ct = nf_ct_tuplehash_to_ctrack(hash); + opts->dir = NF_CT_DIRECTION(hash); + + return ct; +} + +BTF_ID_LIST(btf_nf_conn_ids) +BTF_ID(struct, nf_conn) +BTF_ID(struct, nf_conn___init) + +/* Check writes into `struct nf_conn` */ +static int _nf_conntrack_btf_struct_access(struct bpf_verifier_log *log, + const struct bpf_reg_state *reg, + int off, int size) +{ + const struct btf_type *ncit, *nct, *t; + size_t end; + + ncit = btf_type_by_id(reg->btf, btf_nf_conn_ids[1]); + nct = btf_type_by_id(reg->btf, btf_nf_conn_ids[0]); + t = btf_type_by_id(reg->btf, reg->btf_id); + if (t != nct && t != ncit) { + bpf_log(log, "only read is supported\n"); + return -EACCES; + } + + /* `struct nf_conn` and `struct nf_conn___init` have the same layout + * so we are safe to simply merge offset checks here + */ + switch (off) { +#if defined(CONFIG_NF_CONNTRACK_MARK) + case offsetof(struct nf_conn, mark): + end = offsetofend(struct nf_conn, mark); + break; +#endif + default: + bpf_log(log, "no write support to nf_conn at off %d\n", off); + return -EACCES; + } + + if (off + size > end) { + bpf_log(log, + "write access at off %d with size %d beyond the member of nf_conn ended at %zu\n", + off, size, end); + return -EACCES; + } + + return 0; +} + +__diag_push(); +__diag_ignore_all("-Wmissing-prototypes", + "Global functions as their definitions will be in nf_conntrack BTF"); + +/* bpf_xdp_ct_alloc - Allocate a new CT entry + * + * Parameters: + * @xdp_ctx - Pointer to ctx (xdp_md) in XDP program + * Cannot be NULL + * @bpf_tuple - Pointer to memory representing the tuple to look up + * Cannot be NULL + * @tuple__sz - Length of the tuple structure + * Must be one of sizeof(bpf_tuple->ipv4) or + * sizeof(bpf_tuple->ipv6) + * @opts - Additional options for allocation (documented above) + * Cannot be NULL + * @opts__sz - Length of the bpf_ct_opts structure + * Must be NF_BPF_CT_OPTS_SZ (12) + */ +__bpf_kfunc struct nf_conn___init * +bpf_xdp_ct_alloc(struct xdp_md *xdp_ctx, struct bpf_sock_tuple *bpf_tuple, + u32 tuple__sz, struct bpf_ct_opts *opts, u32 opts__sz) +{ + struct xdp_buff *ctx = (struct xdp_buff *)xdp_ctx; + struct nf_conn *nfct; + + nfct = __bpf_nf_ct_alloc_entry(dev_net(ctx->rxq->dev), bpf_tuple, tuple__sz, + opts, opts__sz, 10); + if (IS_ERR(nfct)) { + if (opts) + opts->error = PTR_ERR(nfct); + return NULL; + } + + return (struct nf_conn___init *)nfct; +} + +/* bpf_xdp_ct_lookup - Lookup CT entry for the given tuple, and acquire a + * reference to it + * + * Parameters: + * @xdp_ctx - Pointer to ctx (xdp_md) in XDP program + * Cannot be NULL + * @bpf_tuple - Pointer to memory representing the tuple to look up + * Cannot be NULL + * @tuple__sz - Length of the tuple structure + * Must be one of sizeof(bpf_tuple->ipv4) or + * sizeof(bpf_tuple->ipv6) + * @opts - Additional options for lookup (documented above) + * Cannot be NULL + * @opts__sz - Length of the bpf_ct_opts structure + * Must be NF_BPF_CT_OPTS_SZ (12) + */ +__bpf_kfunc struct nf_conn * +bpf_xdp_ct_lookup(struct xdp_md *xdp_ctx, struct bpf_sock_tuple *bpf_tuple, + u32 tuple__sz, struct bpf_ct_opts *opts, u32 opts__sz) +{ + struct xdp_buff *ctx = (struct xdp_buff *)xdp_ctx; + struct net *caller_net; + struct nf_conn *nfct; + + caller_net = dev_net(ctx->rxq->dev); + nfct = __bpf_nf_ct_lookup(caller_net, bpf_tuple, tuple__sz, opts, opts__sz); + if (IS_ERR(nfct)) { + if (opts) + opts->error = PTR_ERR(nfct); + return NULL; + } + return nfct; +} + +/* bpf_skb_ct_alloc - Allocate a new CT entry + * + * Parameters: + * @skb_ctx - Pointer to ctx (__sk_buff) in TC program + * Cannot be NULL + * @bpf_tuple - Pointer to memory representing the tuple to look up + * Cannot be NULL + * @tuple__sz - Length of the tuple structure + * Must be one of sizeof(bpf_tuple->ipv4) or + * sizeof(bpf_tuple->ipv6) + * @opts - Additional options for allocation (documented above) + * Cannot be NULL + * @opts__sz - Length of the bpf_ct_opts structure + * Must be NF_BPF_CT_OPTS_SZ (12) + */ +__bpf_kfunc struct nf_conn___init * +bpf_skb_ct_alloc(struct __sk_buff *skb_ctx, struct bpf_sock_tuple *bpf_tuple, + u32 tuple__sz, struct bpf_ct_opts *opts, u32 opts__sz) +{ + struct sk_buff *skb = (struct sk_buff *)skb_ctx; + struct nf_conn *nfct; + struct net *net; + + net = skb->dev ? dev_net(skb->dev) : sock_net(skb->sk); + nfct = __bpf_nf_ct_alloc_entry(net, bpf_tuple, tuple__sz, opts, opts__sz, 10); + if (IS_ERR(nfct)) { + if (opts) + opts->error = PTR_ERR(nfct); + return NULL; + } + + return (struct nf_conn___init *)nfct; +} + +/* bpf_skb_ct_lookup - Lookup CT entry for the given tuple, and acquire a + * reference to it + * + * Parameters: + * @skb_ctx - Pointer to ctx (__sk_buff) in TC program + * Cannot be NULL + * @bpf_tuple - Pointer to memory representing the tuple to look up + * Cannot be NULL + * @tuple__sz - Length of the tuple structure + * Must be one of sizeof(bpf_tuple->ipv4) or + * sizeof(bpf_tuple->ipv6) + * @opts - Additional options for lookup (documented above) + * Cannot be NULL + * @opts__sz - Length of the bpf_ct_opts structure + * Must be NF_BPF_CT_OPTS_SZ (12) + */ +__bpf_kfunc struct nf_conn * +bpf_skb_ct_lookup(struct __sk_buff *skb_ctx, struct bpf_sock_tuple *bpf_tuple, + u32 tuple__sz, struct bpf_ct_opts *opts, u32 opts__sz) +{ + struct sk_buff *skb = (struct sk_buff *)skb_ctx; + struct net *caller_net; + struct nf_conn *nfct; + + caller_net = skb->dev ? dev_net(skb->dev) : sock_net(skb->sk); + nfct = __bpf_nf_ct_lookup(caller_net, bpf_tuple, tuple__sz, opts, opts__sz); + if (IS_ERR(nfct)) { + if (opts) + opts->error = PTR_ERR(nfct); + return NULL; + } + return nfct; +} + +/* bpf_ct_insert_entry - Add the provided entry into a CT map + * + * This must be invoked for referenced PTR_TO_BTF_ID. + * + * @nfct - Pointer to referenced nf_conn___init object, obtained + * using bpf_xdp_ct_alloc or bpf_skb_ct_alloc. + */ +__bpf_kfunc struct nf_conn *bpf_ct_insert_entry(struct nf_conn___init *nfct_i) +{ + struct nf_conn *nfct = (struct nf_conn *)nfct_i; + int err; + + if (!nf_ct_is_confirmed(nfct)) + nfct->timeout += nfct_time_stamp; + nfct->status |= IPS_CONFIRMED; + err = nf_conntrack_hash_check_insert(nfct); + if (err < 0) { + nf_conntrack_free(nfct); + return NULL; + } + return nfct; +} + +/* bpf_ct_release - Release acquired nf_conn object + * + * This must be invoked for referenced PTR_TO_BTF_ID, and the verifier rejects + * the program if any references remain in the program in all of the explored + * states. + * + * Parameters: + * @nf_conn - Pointer to referenced nf_conn object, obtained using + * bpf_xdp_ct_lookup or bpf_skb_ct_lookup. + */ +__bpf_kfunc void bpf_ct_release(struct nf_conn *nfct) +{ + nf_ct_put(nfct); +} + +/* bpf_ct_set_timeout - Set timeout of allocated nf_conn + * + * Sets the default timeout of newly allocated nf_conn before insertion. + * This helper must be invoked for refcounted pointer to nf_conn___init. + * + * Parameters: + * @nfct - Pointer to referenced nf_conn object, obtained using + * bpf_xdp_ct_alloc or bpf_skb_ct_alloc. + * @timeout - Timeout in msecs. + */ +__bpf_kfunc void bpf_ct_set_timeout(struct nf_conn___init *nfct, u32 timeout) +{ + __nf_ct_set_timeout((struct nf_conn *)nfct, msecs_to_jiffies(timeout)); +} + +/* bpf_ct_change_timeout - Change timeout of inserted nf_conn + * + * Change timeout associated of the inserted or looked up nf_conn. + * This helper must be invoked for refcounted pointer to nf_conn. + * + * Parameters: + * @nfct - Pointer to referenced nf_conn object, obtained using + * bpf_ct_insert_entry, bpf_xdp_ct_lookup, or bpf_skb_ct_lookup. + * @timeout - New timeout in msecs. + */ +__bpf_kfunc int bpf_ct_change_timeout(struct nf_conn *nfct, u32 timeout) +{ + return __nf_ct_change_timeout(nfct, msecs_to_jiffies(timeout)); +} + +/* bpf_ct_set_status - Set status field of allocated nf_conn + * + * Set the status field of the newly allocated nf_conn before insertion. + * This must be invoked for referenced PTR_TO_BTF_ID to nf_conn___init. + * + * Parameters: + * @nfct - Pointer to referenced nf_conn object, obtained using + * bpf_xdp_ct_alloc or bpf_skb_ct_alloc. + * @status - New status value. + */ +__bpf_kfunc int bpf_ct_set_status(const struct nf_conn___init *nfct, u32 status) +{ + return nf_ct_change_status_common((struct nf_conn *)nfct, status); +} + +/* bpf_ct_change_status - Change status of inserted nf_conn + * + * Change the status field of the provided connection tracking entry. + * This must be invoked for referenced PTR_TO_BTF_ID to nf_conn. + * + * Parameters: + * @nfct - Pointer to referenced nf_conn object, obtained using + * bpf_ct_insert_entry, bpf_xdp_ct_lookup or bpf_skb_ct_lookup. + * @status - New status value. + */ +__bpf_kfunc int bpf_ct_change_status(struct nf_conn *nfct, u32 status) +{ + return nf_ct_change_status_common(nfct, status); +} + +__diag_pop() + +BTF_SET8_START(nf_ct_kfunc_set) +BTF_ID_FLAGS(func, bpf_xdp_ct_alloc, KF_ACQUIRE | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_xdp_ct_lookup, KF_ACQUIRE | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_skb_ct_alloc, KF_ACQUIRE | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_skb_ct_lookup, KF_ACQUIRE | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_ct_insert_entry, KF_ACQUIRE | KF_RET_NULL | KF_RELEASE) +BTF_ID_FLAGS(func, bpf_ct_release, KF_RELEASE) +BTF_ID_FLAGS(func, bpf_ct_set_timeout, KF_TRUSTED_ARGS) +BTF_ID_FLAGS(func, bpf_ct_change_timeout, KF_TRUSTED_ARGS) +BTF_ID_FLAGS(func, bpf_ct_set_status, KF_TRUSTED_ARGS) +BTF_ID_FLAGS(func, bpf_ct_change_status, KF_TRUSTED_ARGS) +BTF_SET8_END(nf_ct_kfunc_set) + +static const struct btf_kfunc_id_set nf_conntrack_kfunc_set = { + .owner = THIS_MODULE, + .set = &nf_ct_kfunc_set, +}; + +int register_nf_conntrack_bpf(void) +{ + int ret; + + ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP, &nf_conntrack_kfunc_set); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &nf_conntrack_kfunc_set); + if (!ret) { + mutex_lock(&nf_conn_btf_access_lock); + nfct_btf_struct_access = _nf_conntrack_btf_struct_access; + mutex_unlock(&nf_conn_btf_access_lock); + } + + return ret; +} + +void cleanup_nf_conntrack_bpf(void) +{ + mutex_lock(&nf_conn_btf_access_lock); + nfct_btf_struct_access = NULL; + mutex_unlock(&nf_conn_btf_access_lock); +} -- cgit v1.2.3