Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2479 insertions, 0 deletions

diff --git a/net/tipc/crypto.c b/net/tipc/crypto.c
new file mode 100644
index 000000000..b5aa0a835
--- /dev/null
+++ b/net/tipc/crypto.c
@@ -0,0 +1,2479 @@
+// SPDX-License-Identifier: GPL-2.0
+/**
+ * net/tipc/crypto.c: TIPC crypto for key handling & packet en/decryption
+ *
+ * Copyright (c) 2019, Ericsson AB
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the names of the copyright holders nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <crypto/aead.h>
+#include <crypto/aes.h>
+#include <crypto/rng.h>
+#include "crypto.h"
+#include "msg.h"
+#include "bcast.h"
+
+#define TIPC_TX_GRACE_PERIOD	msecs_to_jiffies(5000) /* 5s */
+#define TIPC_TX_LASTING_TIME	msecs_to_jiffies(10000) /* 10s */
+#define TIPC_RX_ACTIVE_LIM	msecs_to_jiffies(3000) /* 3s */
+#define TIPC_RX_PASSIVE_LIM	msecs_to_jiffies(15000) /* 15s */
+
+#define TIPC_MAX_TFMS_DEF	10
+#define TIPC_MAX_TFMS_LIM	1000
+
+#define TIPC_REKEYING_INTV_DEF	(60 * 24) /* default: 1 day */
+
+/**
+ * TIPC Key ids
+ */
+enum {
+	KEY_MASTER = 0,
+	KEY_MIN = KEY_MASTER,
+	KEY_1 = 1,
+	KEY_2,
+	KEY_3,
+	KEY_MAX = KEY_3,
+};
+
+/**
+ * TIPC Crypto statistics
+ */
+enum {
+	STAT_OK,
+	STAT_NOK,
+	STAT_ASYNC,
+	STAT_ASYNC_OK,
+	STAT_ASYNC_NOK,
+	STAT_BADKEYS, /* tx only */
+	STAT_BADMSGS = STAT_BADKEYS, /* rx only */
+	STAT_NOKEYS,
+	STAT_SWITCHES,
+
+	MAX_STATS,
+};
+
+/* TIPC crypto statistics' header */
+static const char *hstats[MAX_STATS] = {"ok", "nok", "async", "async_ok",
+					"async_nok", "badmsgs", "nokeys",
+					"switches"};
+
+/* Max TFMs number per key */
+int sysctl_tipc_max_tfms __read_mostly = TIPC_MAX_TFMS_DEF;
+/* Key exchange switch, default: on */
+int sysctl_tipc_key_exchange_enabled __read_mostly = 1;
+
+/**
+ * struct tipc_key - TIPC keys' status indicator
+ *
+ *         7     6     5     4     3     2     1     0
+ *      +-----+-----+-----+-----+-----+-----+-----+-----+
+ * key: | (reserved)|passive idx| active idx|pending idx|
+ *      +-----+-----+-----+-----+-----+-----+-----+-----+
+ */
+struct tipc_key {
+#define KEY_BITS (2)
+#define KEY_MASK ((1 << KEY_BITS) - 1)
+	union {
+		struct {
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+			u8 pending:2,
+			   active:2,
+			   passive:2, /* rx only */
+			   reserved:2;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+			u8 reserved:2,
+			   passive:2, /* rx only */
+			   active:2,
+			   pending:2;
+#else
+#error  "Please fix <asm/byteorder.h>"
+#endif
+		} __packed;
+		u8 keys;
+	};
+};
+
+/**
+ * struct tipc_tfm - TIPC TFM structure to form a list of TFMs
+ */
+struct tipc_tfm {
+	struct crypto_aead *tfm;
+	struct list_head list;
+};
+
+/**
+ * struct tipc_aead - TIPC AEAD key structure
+ * @tfm_entry: per-cpu pointer to one entry in TFM list
+ * @crypto: TIPC crypto owns this key
+ * @cloned: reference to the source key in case cloning
+ * @users: the number of the key users (TX/RX)
+ * @salt: the key's SALT value
+ * @authsize: authentication tag size (max = 16)
+ * @mode: crypto mode is applied to the key
+ * @hint[]: a hint for user key
+ * @rcu: struct rcu_head
+ * @key: the aead key
+ * @gen: the key's generation
+ * @seqno: the key seqno (cluster scope)
+ * @refcnt: the key reference counter
+ */
+struct tipc_aead {
+#define TIPC_AEAD_HINT_LEN (5)
+	struct tipc_tfm * __percpu *tfm_entry;
+	struct tipc_crypto *crypto;
+	struct tipc_aead *cloned;
+	atomic_t users;
+	u32 salt;
+	u8 authsize;
+	u8 mode;
+	char hint[2 * TIPC_AEAD_HINT_LEN + 1];
+	struct rcu_head rcu;
+	struct tipc_aead_key *key;
+	u16 gen;
+
+	atomic64_t seqno ____cacheline_aligned;
+	refcount_t refcnt ____cacheline_aligned;
+
+} ____cacheline_aligned;
+
+/**
+ * struct tipc_crypto_stats - TIPC Crypto statistics
+ */
+struct tipc_crypto_stats {
+	unsigned int stat[MAX_STATS];
+};
+
+/**
+ * struct tipc_crypto - TIPC TX/RX crypto structure
+ * @net: struct net
+ * @node: TIPC node (RX)
+ * @aead: array of pointers to AEAD keys for encryption/decryption
+ * @peer_rx_active: replicated peer RX active key index
+ * @key_gen: TX/RX key generation
+ * @key: the key states
+ * @skey_mode: session key's mode
+ * @skey: received session key
+ * @wq: common workqueue on TX crypto
+ * @work: delayed work sched for TX/RX
+ * @key_distr: key distributing state
+ * @rekeying_intv: rekeying interval (in minutes)
+ * @stats: the crypto statistics
+ * @name: the crypto name
+ * @sndnxt: the per-peer sndnxt (TX)
+ * @timer1: general timer 1 (jiffies)
+ * @timer2: general timer 2 (jiffies)
+ * @working: the crypto is working or not
+ * @key_master: flag indicates if master key exists
+ * @legacy_user: flag indicates if a peer joins w/o master key (for bwd comp.)
+ * @nokey: no key indication
+ * @lock: tipc_key lock
+ */
+struct tipc_crypto {
+	struct net *net;
+	struct tipc_node *node;
+	struct tipc_aead __rcu *aead[KEY_MAX + 1];
+	atomic_t peer_rx_active;
+	u16 key_gen;
+	struct tipc_key key;
+	u8 skey_mode;
+	struct tipc_aead_key *skey;
+	struct workqueue_struct *wq;
+	struct delayed_work work;
+#define KEY_DISTR_SCHED		1
+#define KEY_DISTR_COMPL		2
+	atomic_t key_distr;
+	u32 rekeying_intv;
+
+	struct tipc_crypto_stats __percpu *stats;
+	char name[48];
+
+	atomic64_t sndnxt ____cacheline_aligned;
+	unsigned long timer1;
+	unsigned long timer2;
+	union {
+		struct {
+			u8 working:1;
+			u8 key_master:1;
+			u8 legacy_user:1;
+			u8 nokey: 1;
+		};
+		u8 flags;
+	};
+	spinlock_t lock; /* crypto lock */
+
+} ____cacheline_aligned;
+
+/* struct tipc_crypto_tx_ctx - TX context for callbacks */
+struct tipc_crypto_tx_ctx {
+	struct tipc_aead *aead;
+	struct tipc_bearer *bearer;
+	struct tipc_media_addr dst;
+};
+
+/* struct tipc_crypto_rx_ctx - RX context for callbacks */
+struct tipc_crypto_rx_ctx {
+	struct tipc_aead *aead;
+	struct tipc_bearer *bearer;
+};
+
+static struct tipc_aead *tipc_aead_get(struct tipc_aead __rcu *aead);
+static inline void tipc_aead_put(struct tipc_aead *aead);
+static void tipc_aead_free(struct rcu_head *rp);
+static int tipc_aead_users(struct tipc_aead __rcu *aead);
+static void tipc_aead_users_inc(struct tipc_aead __rcu *aead, int lim);
+static void tipc_aead_users_dec(struct tipc_aead __rcu *aead, int lim);
+static void tipc_aead_users_set(struct tipc_aead __rcu *aead, int val);
+static struct crypto_aead *tipc_aead_tfm_next(struct tipc_aead *aead);
+static int tipc_aead_init(struct tipc_aead **aead, struct tipc_aead_key *ukey,
+			  u8 mode);
+static int tipc_aead_clone(struct tipc_aead **dst, struct tipc_aead *src);
+static void *tipc_aead_mem_alloc(struct crypto_aead *tfm,
+				 unsigned int crypto_ctx_size,
+				 u8 **iv, struct aead_request **req,
+				 struct scatterlist **sg, int nsg);
+static int tipc_aead_encrypt(struct tipc_aead *aead, struct sk_buff *skb,
+			     struct tipc_bearer *b,
+			     struct tipc_media_addr *dst,
+			     struct tipc_node *__dnode);
+static void tipc_aead_encrypt_done(struct crypto_async_request *base, int err);
+static int tipc_aead_decrypt(struct net *net, struct tipc_aead *aead,
+			     struct sk_buff *skb, struct tipc_bearer *b);
+static void tipc_aead_decrypt_done(struct crypto_async_request *base, int err);
+static inline int tipc_ehdr_size(struct tipc_ehdr *ehdr);
+static int tipc_ehdr_build(struct net *net, struct tipc_aead *aead,
+			   u8 tx_key, struct sk_buff *skb,
+			   struct tipc_crypto *__rx);
+static inline void tipc_crypto_key_set_state(struct tipc_crypto *c,
+					     u8 new_passive,
+					     u8 new_active,
+					     u8 new_pending);
+static int tipc_crypto_key_attach(struct tipc_crypto *c,
+				  struct tipc_aead *aead, u8 pos,
+				  bool master_key);
+static bool tipc_crypto_key_try_align(struct tipc_crypto *rx, u8 new_pending);
+static struct tipc_aead *tipc_crypto_key_pick_tx(struct tipc_crypto *tx,
+						 struct tipc_crypto *rx,
+						 struct sk_buff *skb,
+						 u8 tx_key);
+static void tipc_crypto_key_synch(struct tipc_crypto *rx, struct sk_buff *skb);
+static int tipc_crypto_key_revoke(struct net *net, u8 tx_key);
+static inline void tipc_crypto_clone_msg(struct net *net, struct sk_buff *_skb,
+					 struct tipc_bearer *b,
+					 struct tipc_media_addr *dst,
+					 struct tipc_node *__dnode, u8 type);
+static void tipc_crypto_rcv_complete(struct net *net, struct tipc_aead *aead,
+				     struct tipc_bearer *b,
+				     struct sk_buff **skb, int err);
+static void tipc_crypto_do_cmd(struct net *net, int cmd);
+static char *tipc_crypto_key_dump(struct tipc_crypto *c, char *buf);
+static char *tipc_key_change_dump(struct tipc_key old, struct tipc_key new,
+				  char *buf);
+static int tipc_crypto_key_xmit(struct net *net, struct tipc_aead_key *skey,
+				u16 gen, u8 mode, u32 dnode);
+static bool tipc_crypto_key_rcv(struct tipc_crypto *rx, struct tipc_msg *hdr);
+static void tipc_crypto_work_tx(struct work_struct *work);
+static void tipc_crypto_work_rx(struct work_struct *work);
+static int tipc_aead_key_generate(struct tipc_aead_key *skey);
+
+#define is_tx(crypto) (!(crypto)->node)
+#define is_rx(crypto) (!is_tx(crypto))
+
+#define key_next(cur) ((cur) % KEY_MAX + 1)
+
+#define tipc_aead_rcu_ptr(rcu_ptr, lock)				\
+	rcu_dereference_protected((rcu_ptr), lockdep_is_held(lock))
+
+#define tipc_aead_rcu_replace(rcu_ptr, ptr, lock)			\
+do {									\
+	typeof(rcu_ptr) __tmp = rcu_dereference_protected((rcu_ptr),	\
+						lockdep_is_held(lock));	\
+	rcu_assign_pointer((rcu_ptr), (ptr));				\
+	tipc_aead_put(__tmp);						\
+} while (0)
+
+#define tipc_crypto_key_detach(rcu_ptr, lock)				\
+	tipc_aead_rcu_replace((rcu_ptr), NULL, lock)
+
+/**
+ * tipc_aead_key_validate - Validate a AEAD user key
+ */
+int tipc_aead_key_validate(struct tipc_aead_key *ukey, struct genl_info *info)
+{
+	int keylen;
+
+	/* Check if algorithm exists */
+	if (unlikely(!crypto_has_alg(ukey->alg_name, 0, 0))) {
+		GENL_SET_ERR_MSG(info, "unable to load the algorithm (module existed?)");
+		return -ENODEV;
+	}
+
+	/* Currently, we only support the "gcm(aes)" cipher algorithm */
+	if (strcmp(ukey->alg_name, "gcm(aes)")) {
+		GENL_SET_ERR_MSG(info, "not supported yet the algorithm");
+		return -ENOTSUPP;
+	}
+
+	/* Check if key size is correct */
+	keylen = ukey->keylen - TIPC_AES_GCM_SALT_SIZE;
+	if (unlikely(keylen != TIPC_AES_GCM_KEY_SIZE_128 &&
+		     keylen != TIPC_AES_GCM_KEY_SIZE_192 &&
+		     keylen != TIPC_AES_GCM_KEY_SIZE_256)) {
+		GENL_SET_ERR_MSG(info, "incorrect key length (20, 28 or 36 octets?)");
+		return -EKEYREJECTED;
+	}
+
+	return 0;
+}
+
+/**
+ * tipc_aead_key_generate - Generate new session key
+ * @skey: input/output key with new content
+ *
+ * Return: 0 in case of success, otherwise < 0
+ */
+static int tipc_aead_key_generate(struct tipc_aead_key *skey)
+{
+	int rc = 0;
+
+	/* Fill the key's content with a random value via RNG cipher */
+	rc = crypto_get_default_rng();
+	if (likely(!rc)) {
+		rc = crypto_rng_get_bytes(crypto_default_rng, skey->key,
+					  skey->keylen);
+		crypto_put_default_rng();
+	}
+
+	return rc;
+}
+
+static struct tipc_aead *tipc_aead_get(struct tipc_aead __rcu *aead)
+{
+	struct tipc_aead *tmp;
+
+	rcu_read_lock();
+	tmp = rcu_dereference(aead);
+	if (unlikely(!tmp || !refcount_inc_not_zero(&tmp->refcnt)))
+		tmp = NULL;
+	rcu_read_unlock();
+
+	return tmp;
+}
+
+static inline void tipc_aead_put(struct tipc_aead *aead)
+{
+	if (aead && refcount_dec_and_test(&aead->refcnt))
+		call_rcu(&aead->rcu, tipc_aead_free);
+}
+
+/**
+ * tipc_aead_free - Release AEAD key incl. all the TFMs in the list
+ * @rp: rcu head pointer
+ */
+static void tipc_aead_free(struct rcu_head *rp)
+{
+	struct tipc_aead *aead = container_of(rp, struct tipc_aead, rcu);
+	struct tipc_tfm *tfm_entry, *head, *tmp;
+
+	if (aead->cloned) {
+		tipc_aead_put(aead->cloned);
+	} else {
+		head = *get_cpu_ptr(aead->tfm_entry);
+		put_cpu_ptr(aead->tfm_entry);
+		list_for_each_entry_safe(tfm_entry, tmp, &head->list, list) {
+			crypto_free_aead(tfm_entry->tfm);
+			list_del(&tfm_entry->list);
+			kfree(tfm_entry);
+		}
+		/* Free the head */
+		crypto_free_aead(head->tfm);
+		list_del(&head->list);
+		kfree(head);
+	}
+	free_percpu(aead->tfm_entry);
+	kfree_sensitive(aead->key);
+	kfree(aead);
+}
+
+static int tipc_aead_users(struct tipc_aead __rcu *aead)
+{
+	struct tipc_aead *tmp;
+	int users = 0;
+
+	rcu_read_lock();
+	tmp = rcu_dereference(aead);
+	if (tmp)
+		users = atomic_read(&tmp->users);
+	rcu_read_unlock();
+
+	return users;
+}
+
+static void tipc_aead_users_inc(struct tipc_aead __rcu *aead, int lim)
+{
+	struct tipc_aead *tmp;
+
+	rcu_read_lock();
+	tmp = rcu_dereference(aead);
+	if (tmp)
+		atomic_add_unless(&tmp->users, 1, lim);
+	rcu_read_unlock();
+}
+
+static void tipc_aead_users_dec(struct tipc_aead __rcu *aead, int lim)
+{
+	struct tipc_aead *tmp;
+
+	rcu_read_lock();
+	tmp = rcu_dereference(aead);
+	if (tmp)
+		atomic_add_unless(&rcu_dereference(aead)->users, -1, lim);
+	rcu_read_unlock();
+}
+
+static void tipc_aead_users_set(struct tipc_aead __rcu *aead, int val)
+{
+	struct tipc_aead *tmp;
+	int cur;
+
+	rcu_read_lock();
+	tmp = rcu_dereference(aead);
+	if (tmp) {
+		do {
+			cur = atomic_read(&tmp->users);
+			if (cur == val)
+				break;
+		} while (atomic_cmpxchg(&tmp->users, cur, val) != cur);
+	}
+	rcu_read_unlock();
+}
+
+/**
+ * tipc_aead_tfm_next - Move TFM entry to the next one in list and return it
+ */
+static struct crypto_aead *tipc_aead_tfm_next(struct tipc_aead *aead)
+{
+	struct tipc_tfm **tfm_entry;
+	struct crypto_aead *tfm;
+
+	tfm_entry = get_cpu_ptr(aead->tfm_entry);
+	*tfm_entry = list_next_entry(*tfm_entry, list);
+	tfm = (*tfm_entry)->tfm;
+	put_cpu_ptr(tfm_entry);
+
+	return tfm;
+}
+
+/**
+ * tipc_aead_init - Initiate TIPC AEAD
+ * @aead: returned new TIPC AEAD key handle pointer
+ * @ukey: pointer to user key data
+ * @mode: the key mode
+ *
+ * Allocate a (list of) new cipher transformation (TFM) with the specific user
+ * key data if valid. The number of the allocated TFMs can be set via the sysfs
+ * "net/tipc/max_tfms" first.
+ * Also, all the other AEAD data are also initialized.
+ *
+ * Return: 0 if the initiation is successful, otherwise: < 0
+ */
+static int tipc_aead_init(struct tipc_aead **aead, struct tipc_aead_key *ukey,
+			  u8 mode)
+{
+	struct tipc_tfm *tfm_entry, *head;
+	struct crypto_aead *tfm;
+	struct tipc_aead *tmp;
+	int keylen, err, cpu;
+	int tfm_cnt = 0;
+
+	if (unlikely(*aead))
+		return -EEXIST;
+
+	/* Allocate a new AEAD */
+	tmp = kzalloc(sizeof(*tmp), GFP_ATOMIC);
+	if (unlikely(!tmp))
+		return -ENOMEM;
+
+	/* The key consists of two parts: [AES-KEY][SALT] */
+	keylen = ukey->keylen - TIPC_AES_GCM_SALT_SIZE;
+
+	/* Allocate per-cpu TFM entry pointer */
+	tmp->tfm_entry = alloc_percpu(struct tipc_tfm *);
+	if (!tmp->tfm_entry) {
+		kfree_sensitive(tmp);
+		return -ENOMEM;
+	}
+
+	/* Make a list of TFMs with the user key data */
+	do {
+		tfm = crypto_alloc_aead(ukey->alg_name, 0, 0);
+		if (IS_ERR(tfm)) {
+			err = PTR_ERR(tfm);
+			break;
+		}
+
+		if (unlikely(!tfm_cnt &&
+			     crypto_aead_ivsize(tfm) != TIPC_AES_GCM_IV_SIZE)) {
+			crypto_free_aead(tfm);
+			err = -ENOTSUPP;
+			break;
+		}
+
+		err = crypto_aead_setauthsize(tfm, TIPC_AES_GCM_TAG_SIZE);
+		err |= crypto_aead_setkey(tfm, ukey->key, keylen);
+		if (unlikely(err)) {
+			crypto_free_aead(tfm);
+			break;
+		}
+
+		tfm_entry = kmalloc(sizeof(*tfm_entry), GFP_KERNEL);
+		if (unlikely(!tfm_entry)) {
+			crypto_free_aead(tfm);
+			err = -ENOMEM;
+			break;
+		}
+		INIT_LIST_HEAD(&tfm_entry->list);
+		tfm_entry->tfm = tfm;
+
+		/* First entry? */
+		if (!tfm_cnt) {
+			head = tfm_entry;
+			for_each_possible_cpu(cpu) {
+				*per_cpu_ptr(tmp->tfm_entry, cpu) = head;
+			}
+		} else {
+			list_add_tail(&tfm_entry->list, &head->list);
+		}
+
+	} while (++tfm_cnt < sysctl_tipc_max_tfms);
+
+	/* Not any TFM is allocated? */
+	if (!tfm_cnt) {
+		free_percpu(tmp->tfm_entry);
+		kfree_sensitive(tmp);
+		return err;
+	}
+
+	/* Form a hex string of some last bytes as the key's hint */
+	bin2hex(tmp->hint, ukey->key + keylen - TIPC_AEAD_HINT_LEN,
+		TIPC_AEAD_HINT_LEN);
+
+	/* Initialize the other data */
+	tmp->mode = mode;
+	tmp->cloned = NULL;
+	tmp->authsize = TIPC_AES_GCM_TAG_SIZE;
+	tmp->key = kmemdup(ukey, tipc_aead_key_size(ukey), GFP_KERNEL);
+	if (!tmp->key) {
+		tipc_aead_free(&tmp->rcu);
+		return -ENOMEM;
+	}
+	memcpy(&tmp->salt, ukey->key + keylen, TIPC_AES_GCM_SALT_SIZE);
+	atomic_set(&tmp->users, 0);
+	atomic64_set(&tmp->seqno, 0);
+	refcount_set(&tmp->refcnt, 1);
+
+	*aead = tmp;
+	return 0;
+}
+
+/**
+ * tipc_aead_clone - Clone a TIPC AEAD key
+ * @dst: dest key for the cloning
+ * @src: source key to clone from
+ *
+ * Make a "copy" of the source AEAD key data to the dest, the TFMs list is
+ * common for the keys.
+ * A reference to the source is hold in the "cloned" pointer for the later
+ * freeing purposes.
+ *
+ * Note: this must be done in cluster-key mode only!
+ * Return: 0 in case of success, otherwise < 0
+ */
+static int tipc_aead_clone(struct tipc_aead **dst, struct tipc_aead *src)
+{
+	struct tipc_aead *aead;
+	int cpu;
+
+	if (!src)
+		return -ENOKEY;
+
+	if (src->mode != CLUSTER_KEY)
+		return -EINVAL;
+
+	if (unlikely(*dst))
+		return -EEXIST;
+
+	aead = kzalloc(sizeof(*aead), GFP_ATOMIC);
+	if (unlikely(!aead))
+		return -ENOMEM;
+
+	aead->tfm_entry = alloc_percpu_gfp(struct tipc_tfm *, GFP_ATOMIC);
+	if (unlikely(!aead->tfm_entry)) {
+		kfree_sensitive(aead);
+		return -ENOMEM;
+	}
+
+	for_each_possible_cpu(cpu) {
+		*per_cpu_ptr(aead->tfm_entry, cpu) =
+				*per_cpu_ptr(src->tfm_entry, cpu);
+	}
+
+	memcpy(aead->hint, src->hint, sizeof(src->hint));
+	aead->mode = src->mode;
+	aead->salt = src->salt;
+	aead->authsize = src->authsize;
+	atomic_set(&aead->users, 0);
+	atomic64_set(&aead->seqno, 0);
+	refcount_set(&aead->refcnt, 1);
+
+	WARN_ON(!refcount_inc_not_zero(&src->refcnt));
+	aead->cloned = src;
+
+	*dst = aead;
+	return 0;
+}
+
+/**
+ * tipc_aead_mem_alloc - Allocate memory for AEAD request operations
+ * @tfm: cipher handle to be registered with the request
+ * @crypto_ctx_size: size of crypto context for callback
+ * @iv: returned pointer to IV data
+ * @req: returned pointer to AEAD request data
+ * @sg: returned pointer to SG lists
+ * @nsg: number of SG lists to be allocated
+ *
+ * Allocate memory to store the crypto context data, AEAD request, IV and SG
+ * lists, the memory layout is as follows:
+ * crypto_ctx || iv || aead_req || sg[]
+ *
+ * Return: the pointer to the memory areas in case of success, otherwise NULL
+ */
+static void *tipc_aead_mem_alloc(struct crypto_aead *tfm,
+				 unsigned int crypto_ctx_size,
+				 u8 **iv, struct aead_request **req,
+				 struct scatterlist **sg, int nsg)
+{
+	unsigned int iv_size, req_size;
+	unsigned int len;
+	u8 *mem;
+
+	iv_size = crypto_aead_ivsize(tfm);
+	req_size = sizeof(**req) + crypto_aead_reqsize(tfm);
+
+	len = crypto_ctx_size;
+	len += iv_size;
+	len += crypto_aead_alignmask(tfm) & ~(crypto_tfm_ctx_alignment() - 1);
+	len = ALIGN(len, crypto_tfm_ctx_alignment());
+	len += req_size;
+	len = ALIGN(len, __alignof__(struct scatterlist));
+	len += nsg * sizeof(**sg);
+
+	mem = kmalloc(len, GFP_ATOMIC);
+	if (!mem)
+		return NULL;
+
+	*iv = (u8 *)PTR_ALIGN(mem + crypto_ctx_size,
+			      crypto_aead_alignmask(tfm) + 1);
+	*req = (struct aead_request *)PTR_ALIGN(*iv + iv_size,
+						crypto_tfm_ctx_alignment());
+	*sg = (struct scatterlist *)PTR_ALIGN((u8 *)*req + req_size,
+					      __alignof__(struct scatterlist));
+
+	return (void *)mem;
+}
+
+/**
+ * tipc_aead_encrypt - Encrypt a message
+ * @aead: TIPC AEAD key for the message encryption
+ * @skb: the input/output skb
+ * @b: TIPC bearer where the message will be delivered after the encryption
+ * @dst: the destination media address
+ * @__dnode: TIPC dest node if "known"
+ *
+ * Return:
+ * 0                   : if the encryption has completed
+ * -EINPROGRESS/-EBUSY : if a callback will be performed
+ * < 0                 : the encryption has failed
+ */
+static int tipc_aead_encrypt(struct tipc_aead *aead, struct sk_buff *skb,
+			     struct tipc_bearer *b,
+			     struct tipc_media_addr *dst,
+			     struct tipc_node *__dnode)
+{
+	struct crypto_aead *tfm = tipc_aead_tfm_next(aead);
+	struct tipc_crypto_tx_ctx *tx_ctx;
+	struct aead_request *req;
+	struct sk_buff *trailer;
+	struct scatterlist *sg;
+	struct tipc_ehdr *ehdr;
+	int ehsz, len, tailen, nsg, rc;
+	void *ctx;
+	u32 salt;
+	u8 *iv;
+
+	/* Make sure message len at least 4-byte aligned */
+	len = ALIGN(skb->len, 4);
+	tailen = len - skb->len + aead->authsize;
+
+	/* Expand skb tail for authentication tag:
+	 * As for simplicity, we'd have made sure skb having enough tailroom
+	 * for authentication tag @skb allocation. Even when skb is nonlinear
+	 * but there is no frag_list, it should be still fine!
+	 * Otherwise, we must cow it to be a writable buffer with the tailroom.
+	 */
+	SKB_LINEAR_ASSERT(skb);
+	if (tailen > skb_tailroom(skb)) {
+		pr_debug("TX(): skb tailroom is not enough: %d, requires: %d\n",
+			 skb_tailroom(skb), tailen);
+	}
+
+	if (unlikely(!skb_cloned(skb) && tailen <= skb_tailroom(skb))) {
+		nsg = 1;
+		trailer = skb;
+	} else {
+		/* TODO: We could avoid skb_cow_data() if skb has no frag_list
+		 * e.g. by skb_fill_page_desc() to add another page to the skb
+		 * with the wanted tailen... However, page skbs look not often,
+		 * so take it easy now!
+		 * Cloned skbs e.g. from link_xmit() seems no choice though :(
+		 */
+		nsg = skb_cow_data(skb, tailen, &trailer);
+		if (unlikely(nsg < 0)) {
+			pr_err("TX: skb_cow_data() returned %d\n", nsg);
+			return nsg;
+		}
+	}
+
+	pskb_put(skb, trailer, tailen);
+
+	/* Allocate memory for the AEAD operation */
+	ctx = tipc_aead_mem_alloc(tfm, sizeof(*tx_ctx), &iv, &req, &sg, nsg);
+	if (unlikely(!ctx))
+		return -ENOMEM;
+	TIPC_SKB_CB(skb)->crypto_ctx = ctx;
+
+	/* Map skb to the sg lists */
+	sg_init_table(sg, nsg);
+	rc = skb_to_sgvec(skb, sg, 0, skb->len);
+	if (unlikely(rc < 0)) {
+		pr_err("TX: skb_to_sgvec() returned %d, nsg %d!\n", rc, nsg);
+		goto exit;
+	}
+
+	/* Prepare IV: [SALT (4 octets)][SEQNO (8 octets)]
+	 * In case we're in cluster-key mode, SALT is varied by xor-ing with
+	 * the source address (or w0 of id), otherwise with the dest address
+	 * if dest is known.
+	 */
+	ehdr = (struct tipc_ehdr *)skb->data;
+	salt = aead->salt;
+	if (aead->mode == CLUSTER_KEY)
+		salt ^= ehdr->addr; /* __be32 */
+	else if (__dnode)
+		salt ^= tipc_node_get_addr(__dnode);
+	memcpy(iv, &salt, 4);
+	memcpy(iv + 4, (u8 *)&ehdr->seqno, 8);
+
+	/* Prepare request */
+	ehsz = tipc_ehdr_size(ehdr);
+	aead_request_set_tfm(req, tfm);
+	aead_request_set_ad(req, ehsz);
+	aead_request_set_crypt(req, sg, sg, len - ehsz, iv);
+
+	/* Set callback function & data */
+	aead_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+				  tipc_aead_encrypt_done, skb);
+	tx_ctx = (struct tipc_crypto_tx_ctx *)ctx;
+	tx_ctx->aead = aead;
+	tx_ctx->bearer = b;
+	memcpy(&tx_ctx->dst, dst, sizeof(*dst));
+
+	/* Hold bearer */
+	if (unlikely(!tipc_bearer_hold(b))) {
+		rc = -ENODEV;
+		goto exit;
+	}
+
+	/* Now, do encrypt */
+	rc = crypto_aead_encrypt(req);
+	if (rc == -EINPROGRESS || rc == -EBUSY)
+		return rc;
+
+	tipc_bearer_put(b);
+
+exit:
+	kfree(ctx);
+	TIPC_SKB_CB(skb)->crypto_ctx = NULL;
+	return rc;
+}
+
+static void tipc_aead_encrypt_done(struct crypto_async_request *base, int err)
+{
+	struct sk_buff *skb = base->data;
+	struct tipc_crypto_tx_ctx *tx_ctx = TIPC_SKB_CB(skb)->crypto_ctx;
+	struct tipc_bearer *b = tx_ctx->bearer;
+	struct tipc_aead *aead = tx_ctx->aead;
+	struct tipc_crypto *tx = aead->crypto;
+	struct net *net = tx->net;
+
+	switch (err) {
+	case 0:
+		this_cpu_inc(tx->stats->stat[STAT_ASYNC_OK]);
+		rcu_read_lock();
+		if (likely(test_bit(0, &b->up)))
+			b->media->send_msg(net, skb, b, &tx_ctx->dst);
+		else
+			kfree_skb(skb);
+		rcu_read_unlock();
+		break;
+	case -EINPROGRESS:
+		return;
+	default:
+		this_cpu_inc(tx->stats->stat[STAT_ASYNC_NOK]);
+		kfree_skb(skb);
+		break;
+	}
+
+	kfree(tx_ctx);
+	tipc_bearer_put(b);
+	tipc_aead_put(aead);
+}
+
+/**
+ * tipc_aead_decrypt - Decrypt an encrypted message
+ * @net: struct net
+ * @aead: TIPC AEAD for the message decryption
+ * @skb: the input/output skb
+ * @b: TIPC bearer where the message has been received
+ *
+ * Return:
+ * 0                   : if the decryption has completed
+ * -EINPROGRESS/-EBUSY : if a callback will be performed
+ * < 0                 : the decryption has failed
+ */
+static int tipc_aead_decrypt(struct net *net, struct tipc_aead *aead,
+			     struct sk_buff *skb, struct tipc_bearer *b)
+{
+	struct tipc_crypto_rx_ctx *rx_ctx;
+	struct aead_request *req;
+	struct crypto_aead *tfm;
+	struct sk_buff *unused;
+	struct scatterlist *sg;
+	struct tipc_ehdr *ehdr;
+	int ehsz, nsg, rc;
+	void *ctx;
+	u32 salt;
+	u8 *iv;
+
+	if (unlikely(!aead))
+		return -ENOKEY;
+
+	nsg = skb_cow_data(skb, 0, &unused);
+	if (unlikely(nsg < 0)) {
+		pr_err("RX: skb_cow_data() returned %d\n", nsg);
+		return nsg;
+	}
+
+	/* Allocate memory for the AEAD operation */
+	tfm = tipc_aead_tfm_next(aead);
+	ctx = tipc_aead_mem_alloc(tfm, sizeof(*rx_ctx), &iv, &req, &sg, nsg);
+	if (unlikely(!ctx))
+		return -ENOMEM;
+	TIPC_SKB_CB(skb)->crypto_ctx = ctx;
+
+	/* Map skb to the sg lists */
+	sg_init_table(sg, nsg);
+	rc = skb_to_sgvec(skb, sg, 0, skb->len);
+	if (unlikely(rc < 0)) {
+		pr_err("RX: skb_to_sgvec() returned %d, nsg %d\n", rc, nsg);
+		goto exit;
+	}
+
+	/* Reconstruct IV: */
+	ehdr = (struct tipc_ehdr *)skb->data;
+	salt = aead->salt;
+	if (aead->mode == CLUSTER_KEY)
+		salt ^= ehdr->addr; /* __be32 */
+	else if (ehdr->destined)
+		salt ^= tipc_own_addr(net);
+	memcpy(iv, &salt, 4);
+	memcpy(iv + 4, (u8 *)&ehdr->seqno, 8);
+
+	/* Prepare request */
+	ehsz = tipc_ehdr_size(ehdr);
+	aead_request_set_tfm(req, tfm);
+	aead_request_set_ad(req, ehsz);
+	aead_request_set_crypt(req, sg, sg, skb->len - ehsz, iv);
+
+	/* Set callback function & data */
+	aead_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+				  tipc_aead_decrypt_done, skb);
+	rx_ctx = (struct tipc_crypto_rx_ctx *)ctx;
+	rx_ctx->aead = aead;
+	rx_ctx->bearer = b;
+
+	/* Hold bearer */
+	if (unlikely(!tipc_bearer_hold(b))) {
+		rc = -ENODEV;
+		goto exit;
+	}
+
+	/* Now, do decrypt */
+	rc = crypto_aead_decrypt(req);
+	if (rc == -EINPROGRESS || rc == -EBUSY)
+		return rc;
+
+	tipc_bearer_put(b);
+
+exit:
+	kfree(ctx);
+	TIPC_SKB_CB(skb)->crypto_ctx = NULL;
+	return rc;
+}
+
+static void tipc_aead_decrypt_done(struct crypto_async_request *base, int err)
+{
+	struct sk_buff *skb = base->data;
+	struct tipc_crypto_rx_ctx *rx_ctx = TIPC_SKB_CB(skb)->crypto_ctx;
+	struct tipc_bearer *b = rx_ctx->bearer;
+	struct tipc_aead *aead = rx_ctx->aead;
+	struct tipc_crypto_stats __percpu *stats = aead->crypto->stats;
+	struct net *net = aead->crypto->net;
+
+	switch (err) {
+	case 0:
+		this_cpu_inc(stats->stat[STAT_ASYNC_OK]);
+		break;
+	case -EINPROGRESS:
+		return;
+	default:
+		this_cpu_inc(stats->stat[STAT_ASYNC_NOK]);
+		break;
+	}
+
+	kfree(rx_ctx);
+	tipc_crypto_rcv_complete(net, aead, b, &skb, err);
+	if (likely(skb)) {
+		if (likely(test_bit(0, &b->up)))
+			tipc_rcv(net, skb, b);
+		else
+			kfree_skb(skb);
+	}
+
+	tipc_bearer_put(b);
+}
+
+static inline int tipc_ehdr_size(struct tipc_ehdr *ehdr)
+{
+	return (ehdr->user != LINK_CONFIG) ? EHDR_SIZE : EHDR_CFG_SIZE;
+}
+
+/**
+ * tipc_ehdr_validate - Validate an encryption message
+ * @skb: the message buffer
+ *
+ * Returns "true" if this is a valid encryption message, otherwise "false"
+ */
+bool tipc_ehdr_validate(struct sk_buff *skb)
+{
+	struct tipc_ehdr *ehdr;
+	int ehsz;
+
+	if (unlikely(!pskb_may_pull(skb, EHDR_MIN_SIZE)))
+		return false;
+
+	ehdr = (struct tipc_ehdr *)skb->data;
+	if (unlikely(ehdr->version != TIPC_EVERSION))
+		return false;
+	ehsz = tipc_ehdr_size(ehdr);
+	if (unlikely(!pskb_may_pull(skb, ehsz)))
+		return false;
+	if (unlikely(skb->len <= ehsz + TIPC_AES_GCM_TAG_SIZE))
+		return false;
+
+	return true;
+}
+
+/**
+ * tipc_ehdr_build - Build TIPC encryption message header
+ * @net: struct net
+ * @aead: TX AEAD key to be used for the message encryption
+ * @tx_key: key id used for the message encryption
+ * @skb: input/output message skb
+ * @__rx: RX crypto handle if dest is "known"
+ *
+ * Return: the header size if the building is successful, otherwise < 0
+ */
+static int tipc_ehdr_build(struct net *net, struct tipc_aead *aead,
+			   u8 tx_key, struct sk_buff *skb,
+			   struct tipc_crypto *__rx)
+{
+	struct tipc_msg *hdr = buf_msg(skb);
+	struct tipc_ehdr *ehdr;
+	u32 user = msg_user(hdr);
+	u64 seqno;
+	int ehsz;
+
+	/* Make room for encryption header */
+	ehsz = (user != LINK_CONFIG) ? EHDR_SIZE : EHDR_CFG_SIZE;
+	WARN_ON(skb_headroom(skb) < ehsz);
+	ehdr = (struct tipc_ehdr *)skb_push(skb, ehsz);
+
+	/* Obtain a seqno first:
+	 * Use the key seqno (= cluster wise) if dest is unknown or we're in
+	 * cluster key mode, otherwise it's better for a per-peer seqno!
+	 */
+	if (!__rx || aead->mode == CLUSTER_KEY)
+		seqno = atomic64_inc_return(&aead->seqno);
+	else
+		seqno = atomic64_inc_return(&__rx->sndnxt);
+
+	/* Revoke the key if seqno is wrapped around */
+	if (unlikely(!seqno))
+		return tipc_crypto_key_revoke(net, tx_key);
+
+	/* Word 1-2 */
+	ehdr->seqno = cpu_to_be64(seqno);
+
+	/* Words 0, 3- */
+	ehdr->version = TIPC_EVERSION;
+	ehdr->user = 0;
+	ehdr->keepalive = 0;
+	ehdr->tx_key = tx_key;
+	ehdr->destined = (__rx) ? 1 : 0;
+	ehdr->rx_key_active = (__rx) ? __rx->key.active : 0;
+	ehdr->rx_nokey = (__rx) ? __rx->nokey : 0;
+	ehdr->master_key = aead->crypto->key_master;
+	ehdr->reserved_1 = 0;
+	ehdr->reserved_2 = 0;
+
+	switch (user) {
+	case LINK_CONFIG:
+		ehdr->user = LINK_CONFIG;
+		memcpy(ehdr->id, tipc_own_id(net), NODE_ID_LEN);
+		break;
+	default:
+		if (user == LINK_PROTOCOL && msg_type(hdr) == STATE_MSG) {
+			ehdr->user = LINK_PROTOCOL;
+			ehdr->keepalive = msg_is_keepalive(hdr);
+		}
+		ehdr->addr = hdr->hdr[3];
+		break;
+	}
+
+	return ehsz;
+}
+
+static inline void tipc_crypto_key_set_state(struct tipc_crypto *c,
+					     u8 new_passive,
+					     u8 new_active,
+					     u8 new_pending)
+{
+	struct tipc_key old = c->key;
+	char buf[32];
+
+	c->key.keys = ((new_passive & KEY_MASK) << (KEY_BITS * 2)) |
+		      ((new_active  & KEY_MASK) << (KEY_BITS)) |
+		      ((new_pending & KEY_MASK));
+
+	pr_debug("%s: key changing %s ::%pS\n", c->name,
+		 tipc_key_change_dump(old, c->key, buf),
+		 __builtin_return_address(0));
+}
+
+/**
+ * tipc_crypto_key_init - Initiate a new user / AEAD key
+ * @c: TIPC crypto to which new key is attached
+ * @ukey: the user key
+ * @mode: the key mode (CLUSTER_KEY or PER_NODE_KEY)
+ * @master_key: specify this is a cluster master key
+ *
+ * A new TIPC AEAD key will be allocated and initiated with the specified user
+ * key, then attached to the TIPC crypto.
+ *
+ * Return: new key id in case of success, otherwise: < 0
+ */
+int tipc_crypto_key_init(struct tipc_crypto *c, struct tipc_aead_key *ukey,
+			 u8 mode, bool master_key)
+{
+	struct tipc_aead *aead = NULL;
+	int rc = 0;
+
+	/* Initiate with the new user key */
+	rc = tipc_aead_init(&aead, ukey, mode);
+
+	/* Attach it to the crypto */
+	if (likely(!rc)) {
+		rc = tipc_crypto_key_attach(c, aead, 0, master_key);
+		if (rc < 0)
+			tipc_aead_free(&aead->rcu);
+	}
+
+	return rc;
+}
+
+/**
+ * tipc_crypto_key_attach - Attach a new AEAD key to TIPC crypto
+ * @c: TIPC crypto to which the new AEAD key is attached
+ * @aead: the new AEAD key pointer
+ * @pos: desired slot in the crypto key array, = 0 if any!
+ * @master_key: specify this is a cluster master key
+ *
+ * Return: new key id in case of success, otherwise: -EBUSY
+ */
+static int tipc_crypto_key_attach(struct tipc_crypto *c,
+				  struct tipc_aead *aead, u8 pos,
+				  bool master_key)
+{
+	struct tipc_key key;
+	int rc = -EBUSY;
+	u8 new_key;
+
+	spin_lock_bh(&c->lock);
+	key = c->key;
+	if (master_key) {
+		new_key = KEY_MASTER;
+		goto attach;
+	}
+	if (key.active && key.passive)
+		goto exit;
+	if (key.pending) {
+		if (tipc_aead_users(c->aead[key.pending]) > 0)
+			goto exit;
+		/* if (pos): ok with replacing, will be aligned when needed */
+		/* Replace it */
+		new_key = key.pending;
+	} else {
+		if (pos) {
+			if (key.active && pos != key_next(key.active)) {
+				key.passive = pos;
+				new_key = pos;
+				goto attach;
+			} else if (!key.active && !key.passive) {
+				key.pending = pos;
+				new_key = pos;
+				goto attach;
+			}
+		}
+		key.pending = key_next(key.active ?: key.passive);
+		new_key = key.pending;
+	}
+
+attach:
+	aead->crypto = c;
+	aead->gen = (is_tx(c)) ? ++c->key_gen : c->key_gen;
+	tipc_aead_rcu_replace(c->aead[new_key], aead, &c->lock);
+	if (likely(c->key.keys != key.keys))
+		tipc_crypto_key_set_state(c, key.passive, key.active,
+					  key.pending);
+	c->working = 1;
+	c->nokey = 0;
+	c->key_master |= master_key;
+	rc = new_key;
+
+exit:
+	spin_unlock_bh(&c->lock);
+	return rc;
+}
+
+void tipc_crypto_key_flush(struct tipc_crypto *c)
+{
+	struct tipc_crypto *tx, *rx;
+	int k;
+
+	spin_lock_bh(&c->lock);
+	if (is_rx(c)) {
+		/* Try to cancel pending work */
+		rx = c;
+		tx = tipc_net(rx->net)->crypto_tx;
+		if (cancel_delayed_work(&rx->work)) {
+			kfree(rx->skey);
+			rx->skey = NULL;
+			atomic_xchg(&rx->key_distr, 0);
+			tipc_node_put(rx->node);
+		}
+		/* RX stopping => decrease TX key users if any */
+		k = atomic_xchg(&rx->peer_rx_active, 0);
+		if (k) {
+			tipc_aead_users_dec(tx->aead[k], 0);
+			/* Mark the point TX key users changed */
+			tx->timer1 = jiffies;
+		}
+	}
+
+	c->flags = 0;
+	tipc_crypto_key_set_state(c, 0, 0, 0);
+	for (k = KEY_MIN; k <= KEY_MAX; k++)
+		tipc_crypto_key_detach(c->aead[k], &c->lock);
+	atomic64_set(&c->sndnxt, 0);
+	spin_unlock_bh(&c->lock);
+}
+
+/**
+ * tipc_crypto_key_try_align - Align RX keys if possible
+ * @rx: RX crypto handle
+ * @new_pending: new pending slot if aligned (= TX key from peer)
+ *
+ * Peer has used an unknown key slot, this only happens when peer has left and
+ * rejoned, or we are newcomer.
+ * That means, there must be no active key but a pending key at unaligned slot.
+ * If so, we try to move the pending key to the new slot.
+ * Note: A potential passive key can exist, it will be shifted correspondingly!
+ *
+ * Return: "true" if key is successfully aligned, otherwise "false"
+ */
+static bool tipc_crypto_key_try_align(struct tipc_crypto *rx, u8 new_pending)
+{
+	struct tipc_aead *tmp1, *tmp2 = NULL;
+	struct tipc_key key;
+	bool aligned = false;
+	u8 new_passive = 0;
+	int x;
+
+	spin_lock(&rx->lock);
+	key = rx->key;
+	if (key.pending == new_pending) {
+		aligned = true;
+		goto exit;
+	}
+	if (key.active)
+		goto exit;
+	if (!key.pending)
+		goto exit;
+	if (tipc_aead_users(rx->aead[key.pending]) > 0)
+		goto exit;
+
+	/* Try to "isolate" this pending key first */
+	tmp1 = tipc_aead_rcu_ptr(rx->aead[key.pending], &rx->lock);
+	if (!refcount_dec_if_one(&tmp1->refcnt))
+		goto exit;
+	rcu_assign_pointer(rx->aead[key.pending], NULL);
+
+	/* Move passive key if any */
+	if (key.passive) {
+		tmp2 = rcu_replace_pointer(rx->aead[key.passive], tmp2, lockdep_is_held(&rx->lock));
+		x = (key.passive - key.pending + new_pending) % KEY_MAX;
+		new_passive = (x <= 0) ? x + KEY_MAX : x;
+	}
+
+	/* Re-allocate the key(s) */
+	tipc_crypto_key_set_state(rx, new_passive, 0, new_pending);
+	rcu_assign_pointer(rx->aead[new_pending], tmp1);
+	if (new_passive)
+		rcu_assign_pointer(rx->aead[new_passive], tmp2);
+	refcount_set(&tmp1->refcnt, 1);
+	aligned = true;
+	pr_info_ratelimited("%s: key[%d] -> key[%d]\n", rx->name, key.pending,
+			    new_pending);
+
+exit:
+	spin_unlock(&rx->lock);
+	return aligned;
+}
+
+/**
+ * tipc_crypto_key_pick_tx - Pick one TX key for message decryption
+ * @tx: TX crypto handle
+ * @rx: RX crypto handle (can be NULL)
+ * @skb: the message skb which will be decrypted later
+ * @tx_key: peer TX key id
+ *
+ * This function looks up the existing TX keys and pick one which is suitable
+ * for the message decryption, that must be a cluster key and not used before
+ * on the same message (i.e. recursive).
+ *
+ * Return: the TX AEAD key handle in case of success, otherwise NULL
+ */
+static struct tipc_aead *tipc_crypto_key_pick_tx(struct tipc_crypto *tx,
+						 struct tipc_crypto *rx,
+						 struct sk_buff *skb,
+						 u8 tx_key)
+{
+	struct tipc_skb_cb *skb_cb = TIPC_SKB_CB(skb);
+	struct tipc_aead *aead = NULL;
+	struct tipc_key key = tx->key;
+	u8 k, i = 0;
+
+	/* Initialize data if not yet */
+	if (!skb_cb->tx_clone_deferred) {
+		skb_cb->tx_clone_deferred = 1;
+		memset(&skb_cb->tx_clone_ctx, 0, sizeof(skb_cb->tx_clone_ctx));
+	}
+
+	skb_cb->tx_clone_ctx.rx = rx;
+	if (++skb_cb->tx_clone_ctx.recurs > 2)
+		return NULL;
+
+	/* Pick one TX key */
+	spin_lock(&tx->lock);
+	if (tx_key == KEY_MASTER) {
+		aead = tipc_aead_rcu_ptr(tx->aead[KEY_MASTER], &tx->lock);
+		goto done;
+	}
+	do {
+		k = (i == 0) ? key.pending :
+			((i == 1) ? key.active : key.passive);
+		if (!k)
+			continue;
+		aead = tipc_aead_rcu_ptr(tx->aead[k], &tx->lock);
+		if (!aead)
+			continue;
+		if (aead->mode != CLUSTER_KEY ||
+		    aead == skb_cb->tx_clone_ctx.last) {
+			aead = NULL;
+			continue;
+		}
+		/* Ok, found one cluster key */
+		skb_cb->tx_clone_ctx.last = aead;
+		WARN_ON(skb->next);
+		skb->next = skb_clone(skb, GFP_ATOMIC);
+		if (unlikely(!skb->next))
+			pr_warn("Failed to clone skb for next round if any\n");
+		break;
+	} while (++i < 3);
+
+done:
+	if (likely(aead))
+		WARN_ON(!refcount_inc_not_zero(&aead->refcnt));
+	spin_unlock(&tx->lock);
+
+	return aead;
+}
+
+/**
+ * tipc_crypto_key_synch: Synch own key data according to peer key status
+ * @rx: RX crypto handle
+ * @skb: TIPCv2 message buffer (incl. the ehdr from peer)
+ *
+ * This function updates the peer node related data as the peer RX active key
+ * has changed, so the number of TX keys' users on this node are increased and
+ * decreased correspondingly.
+ *
+ * It also considers if peer has no key, then we need to make own master key
+ * (if any) taking over i.e. starting grace period and also trigger key
+ * distributing process.
+ *
+ * The "per-peer" sndnxt is also reset when the peer key has switched.
+ */
+static void tipc_crypto_key_synch(struct tipc_crypto *rx, struct sk_buff *skb)
+{
+	struct tipc_ehdr *ehdr = (struct tipc_ehdr *)skb_network_header(skb);
+	struct tipc_crypto *tx = tipc_net(rx->net)->crypto_tx;
+	struct tipc_msg *hdr = buf_msg(skb);
+	u32 self = tipc_own_addr(rx->net);
+	u8 cur, new;
+	unsigned long delay;
+
+	/* Update RX 'key_master' flag according to peer, also mark "legacy" if
+	 * a peer has no master key.
+	 */
+	rx->key_master = ehdr->master_key;
+	if (!rx->key_master)
+		tx->legacy_user = 1;
+
+	/* For later cases, apply only if message is destined to this node */
+	if (!ehdr->destined || msg_short(hdr) || msg_destnode(hdr) != self)
+		return;
+
+	/* Case 1: Peer has no keys, let's make master key take over */
+	if (ehdr->rx_nokey) {
+		/* Set or extend grace period */
+		tx->timer2 = jiffies;
+		/* Schedule key distributing for the peer if not yet */
+		if (tx->key.keys &&
+		    !atomic_cmpxchg(&rx->key_distr, 0, KEY_DISTR_SCHED)) {
+			get_random_bytes(&delay, 2);
+			delay %= 5;
+			delay = msecs_to_jiffies(500 * ++delay);
+			if (queue_delayed_work(tx->wq, &rx->work, delay))
+				tipc_node_get(rx->node);
+		}
+	} else {
+		/* Cancel a pending key distributing if any */
+		atomic_xchg(&rx->key_distr, 0);
+	}
+
+	/* Case 2: Peer RX active key has changed, let's update own TX users */
+	cur = atomic_read(&rx->peer_rx_active);
+	new = ehdr->rx_key_active;
+	if (tx->key.keys &&
+	    cur != new &&
+	    atomic_cmpxchg(&rx->peer_rx_active, cur, new) == cur) {
+		if (new)
+			tipc_aead_users_inc(tx->aead[new], INT_MAX);
+		if (cur)
+			tipc_aead_users_dec(tx->aead[cur], 0);
+
+		atomic64_set(&rx->sndnxt, 0);
+		/* Mark the point TX key users changed */
+		tx->timer1 = jiffies;
+
+		pr_debug("%s: key users changed %d-- %d++, peer %s\n",
+			 tx->name, cur, new, rx->name);
+	}
+}
+
+static int tipc_crypto_key_revoke(struct net *net, u8 tx_key)
+{
+	struct tipc_crypto *tx = tipc_net(net)->crypto_tx;
+	struct tipc_key key;
+
+	spin_lock_bh(&tx->lock);
+	key = tx->key;
+	WARN_ON(!key.active || tx_key != key.active);
+
+	/* Free the active key */
+	tipc_crypto_key_set_state(tx, key.passive, 0, key.pending);
+	tipc_crypto_key_detach(tx->aead[key.active], &tx->lock);
+	spin_unlock_bh(&tx->lock);
+
+	pr_warn("%s: key is revoked\n", tx->name);
+	return -EKEYREVOKED;
+}
+
+int tipc_crypto_start(struct tipc_crypto **crypto, struct net *net,
+		      struct tipc_node *node)
+{
+	struct tipc_crypto *c;
+
+	if (*crypto)
+		return -EEXIST;
+
+	/* Allocate crypto */
+	c = kzalloc(sizeof(*c), GFP_ATOMIC);
+	if (!c)
+		return -ENOMEM;
+
+	/* Allocate workqueue on TX */
+	if (!node) {
+		c->wq = alloc_ordered_workqueue("tipc_crypto", 0);
+		if (!c->wq) {
+			kfree(c);
+			return -ENOMEM;
+		}
+	}
+
+	/* Allocate statistic structure */
+	c->stats = alloc_percpu_gfp(struct tipc_crypto_stats, GFP_ATOMIC);
+	if (!c->stats) {
+		if (c->wq)
+			destroy_workqueue(c->wq);
+		kfree_sensitive(c);
+		return -ENOMEM;
+	}
+
+	c->flags = 0;
+	c->net = net;
+	c->node = node;
+	get_random_bytes(&c->key_gen, 2);
+	tipc_crypto_key_set_state(c, 0, 0, 0);
+	atomic_set(&c->key_distr, 0);
+	atomic_set(&c->peer_rx_active, 0);
+	atomic64_set(&c->sndnxt, 0);
+	c->timer1 = jiffies;
+	c->timer2 = jiffies;
+	c->rekeying_intv = TIPC_REKEYING_INTV_DEF;
+	spin_lock_init(&c->lock);
+	scnprintf(c->name, 48, "%s(%s)", (is_rx(c)) ? "RX" : "TX",
+		  (is_rx(c)) ? tipc_node_get_id_str(c->node) :
+			       tipc_own_id_string(c->net));
+
+	if (is_rx(c))
+		INIT_DELAYED_WORK(&c->work, tipc_crypto_work_rx);
+	else
+		INIT_DELAYED_WORK(&c->work, tipc_crypto_work_tx);
+
+	*crypto = c;
+	return 0;
+}
+
+void tipc_crypto_stop(struct tipc_crypto **crypto)
+{
+	struct tipc_crypto *c = *crypto;
+	u8 k;
+
+	if (!c)
+		return;
+
+	/* Flush any queued works & destroy wq */
+	if (is_tx(c)) {
+		c->rekeying_intv = 0;
+		cancel_delayed_work_sync(&c->work);
+		destroy_workqueue(c->wq);
+	}
+
+	/* Release AEAD keys */
+	rcu_read_lock();
+	for (k = KEY_MIN; k <= KEY_MAX; k++)
+		tipc_aead_put(rcu_dereference(c->aead[k]));
+	rcu_read_unlock();
+	pr_debug("%s: has been stopped\n", c->name);
+
+	/* Free this crypto statistics */
+	free_percpu(c->stats);
+
+	*crypto = NULL;
+	kfree_sensitive(c);
+}
+
+void tipc_crypto_timeout(struct tipc_crypto *rx)
+{
+	struct tipc_net *tn = tipc_net(rx->net);
+	struct tipc_crypto *tx = tn->crypto_tx;
+	struct tipc_key key;
+	int cmd;
+
+	/* TX pending: taking all users & stable -> active */
+	spin_lock(&tx->lock);
+	key = tx->key;
+	if (key.active && tipc_aead_users(tx->aead[key.active]) > 0)
+		goto s1;
+	if (!key.pending || tipc_aead_users(tx->aead[key.pending]) <= 0)
+		goto s1;
+	if (time_before(jiffies, tx->timer1 + TIPC_TX_LASTING_TIME))
+		goto s1;
+
+	tipc_crypto_key_set_state(tx, key.passive, key.pending, 0);
+	if (key.active)
+		tipc_crypto_key_detach(tx->aead[key.active], &tx->lock);
+	this_cpu_inc(tx->stats->stat[STAT_SWITCHES]);
+	pr_info("%s: key[%d] is activated\n", tx->name, key.pending);
+
+s1:
+	spin_unlock(&tx->lock);
+
+	/* RX pending: having user -> active */
+	spin_lock(&rx->lock);
+	key = rx->key;
+	if (!key.pending || tipc_aead_users(rx->aead[key.pending]) <= 0)
+		goto s2;
+
+	if (key.active)
+		key.passive = key.active;
+	key.active = key.pending;
+	rx->timer2 = jiffies;
+	tipc_crypto_key_set_state(rx, key.passive, key.active, 0);
+	this_cpu_inc(rx->stats->stat[STAT_SWITCHES]);
+	pr_info("%s: key[%d] is activated\n", rx->name, key.pending);
+	goto s5;
+
+s2:
+	/* RX pending: not working -> remove */
+	if (!key.pending || tipc_aead_users(rx->aead[key.pending]) > -10)
+		goto s3;
+
+	tipc_crypto_key_set_state(rx, key.passive, key.active, 0);
+	tipc_crypto_key_detach(rx->aead[key.pending], &rx->lock);
+	pr_debug("%s: key[%d] is removed\n", rx->name, key.pending);
+	goto s5;
+
+s3:
+	/* RX active: timed out or no user -> pending */
+	if (!key.active)
+		goto s4;
+	if (time_before(jiffies, rx->timer1 + TIPC_RX_ACTIVE_LIM) &&
+	    tipc_aead_users(rx->aead[key.active]) > 0)
+		goto s4;
+
+	if (key.pending)
+		key.passive = key.active;
+	else
+		key.pending = key.active;
+	rx->timer2 = jiffies;
+	tipc_crypto_key_set_state(rx, key.passive, 0, key.pending);
+	tipc_aead_users_set(rx->aead[key.pending], 0);
+	pr_debug("%s: key[%d] is deactivated\n", rx->name, key.active);
+	goto s5;
+
+s4:
+	/* RX passive: outdated or not working -> free */
+	if (!key.passive)
+		goto s5;
+	if (time_before(jiffies, rx->timer2 + TIPC_RX_PASSIVE_LIM) &&
+	    tipc_aead_users(rx->aead[key.passive]) > -10)
+		goto s5;
+
+	tipc_crypto_key_set_state(rx, 0, key.active, key.pending);
+	tipc_crypto_key_detach(rx->aead[key.passive], &rx->lock);
+	pr_debug("%s: key[%d] is freed\n", rx->name, key.passive);
+
+s5:
+	spin_unlock(&rx->lock);
+
+	/* Relax it here, the flag will be set again if it really is, but only
+	 * when we are not in grace period for safety!
+	 */
+	if (time_after(jiffies, tx->timer2 + TIPC_TX_GRACE_PERIOD))
+		tx->legacy_user = 0;
+
+	/* Limit max_tfms & do debug commands if needed */
+	if (likely(sysctl_tipc_max_tfms <= TIPC_MAX_TFMS_LIM))
+		return;
+
+	cmd = sysctl_tipc_max_tfms;
+	sysctl_tipc_max_tfms = TIPC_MAX_TFMS_DEF;
+	tipc_crypto_do_cmd(rx->net, cmd);
+}
+
+static inline void tipc_crypto_clone_msg(struct net *net, struct sk_buff *_skb,
+					 struct tipc_bearer *b,
+					 struct tipc_media_addr *dst,
+					 struct tipc_node *__dnode, u8 type)
+{
+	struct sk_buff *skb;
+
+	skb = skb_clone(_skb, GFP_ATOMIC);
+	if (skb) {
+		TIPC_SKB_CB(skb)->xmit_type = type;
+		tipc_crypto_xmit(net, &skb, b, dst, __dnode);
+		if (skb)
+			b->media->send_msg(net, skb, b, dst);
+	}
+}
+
+/**
+ * tipc_crypto_xmit - Build & encrypt TIPC message for xmit
+ * @net: struct net
+ * @skb: input/output message skb pointer
+ * @b: bearer used for xmit later
+ * @dst: destination media address
+ * @__dnode: destination node for reference if any
+ *
+ * First, build an encryption message header on the top of the message, then
+ * encrypt the original TIPC message by using the pending, master or active
+ * key with this preference order.
+ * If the encryption is successful, the encrypted skb is returned directly or
+ * via the callback.
+ * Otherwise, the skb is freed!
+ *
+ * Return:
+ * 0                   : the encryption has succeeded (or no encryption)
+ * -EINPROGRESS/-EBUSY : the encryption is ongoing, a callback will be made
+ * -ENOKEK             : the encryption has failed due to no key
+ * -EKEYREVOKED        : the encryption has failed due to key revoked
+ * -ENOMEM             : the encryption has failed due to no memory
+ * < 0                 : the encryption has failed due to other reasons
+ */
+int tipc_crypto_xmit(struct net *net, struct sk_buff **skb,
+		     struct tipc_bearer *b, struct tipc_media_addr *dst,
+		     struct tipc_node *__dnode)
+{
+	struct tipc_crypto *__rx = tipc_node_crypto_rx(__dnode);
+	struct tipc_crypto *tx = tipc_net(net)->crypto_tx;
+	struct tipc_crypto_stats __percpu *stats = tx->stats;
+	struct tipc_msg *hdr = buf_msg(*skb);
+	struct tipc_key key = tx->key;
+	struct tipc_aead *aead = NULL;
+	u32 user = msg_user(hdr);
+	u32 type = msg_type(hdr);
+	int rc = -ENOKEY;
+	u8 tx_key = 0;
+
+	/* No encryption? */
+	if (!tx->working)
+		return 0;
+
+	/* Pending key if peer has active on it or probing time */
+	if (unlikely(key.pending)) {
+		tx_key = key.pending;
+		if (!tx->key_master && !key.active)
+			goto encrypt;
+		if (__rx && atomic_read(&__rx->peer_rx_active) == tx_key)
+			goto encrypt;
+		if (TIPC_SKB_CB(*skb)->xmit_type == SKB_PROBING) {
+			pr_debug("%s: probing for key[%d]\n", tx->name,
+				 key.pending);
+			goto encrypt;
+		}
+		if (user == LINK_CONFIG || user == LINK_PROTOCOL)
+			tipc_crypto_clone_msg(net, *skb, b, dst, __dnode,
+					      SKB_PROBING);
+	}
+
+	/* Master key if this is a *vital* message or in grace period */
+	if (tx->key_master) {
+		tx_key = KEY_MASTER;
+		if (!key.active)
+			goto encrypt;
+		if (TIPC_SKB_CB(*skb)->xmit_type == SKB_GRACING) {
+			pr_debug("%s: gracing for msg (%d %d)\n", tx->name,
+				 user, type);
+			goto encrypt;
+		}
+		if (user == LINK_CONFIG ||
+		    (user == LINK_PROTOCOL && type == RESET_MSG) ||
+		    (user == MSG_CRYPTO && type == KEY_DISTR_MSG) ||
+		    time_before(jiffies, tx->timer2 + TIPC_TX_GRACE_PERIOD)) {
+			if (__rx && __rx->key_master &&
+			    !atomic_read(&__rx->peer_rx_active))
+				goto encrypt;
+			if (!__rx) {
+				if (likely(!tx->legacy_user))
+					goto encrypt;
+				tipc_crypto_clone_msg(net, *skb, b, dst,
+						      __dnode, SKB_GRACING);
+			}
+		}
+	}
+
+	/* Else, use the active key if any */
+	if (likely(key.active)) {
+		tx_key = key.active;
+		goto encrypt;
+	}
+
+	goto exit;
+
+encrypt:
+	aead = tipc_aead_get(tx->aead[tx_key]);
+	if (unlikely(!aead))
+		goto exit;
+	rc = tipc_ehdr_build(net, aead, tx_key, *skb, __rx);
+	if (likely(rc > 0))
+		rc = tipc_aead_encrypt(aead, *skb, b, dst, __dnode);
+
+exit:
+	switch (rc) {
+	case 0:
+		this_cpu_inc(stats->stat[STAT_OK]);
+		break;
+	case -EINPROGRESS:
+	case -EBUSY:
+		this_cpu_inc(stats->stat[STAT_ASYNC]);
+		*skb = NULL;
+		return rc;
+	default:
+		this_cpu_inc(stats->stat[STAT_NOK]);
+		if (rc == -ENOKEY)
+			this_cpu_inc(stats->stat[STAT_NOKEYS]);
+		else if (rc == -EKEYREVOKED)
+			this_cpu_inc(stats->stat[STAT_BADKEYS]);
+		kfree_skb(*skb);
+		*skb = NULL;
+		break;
+	}
+
+	tipc_aead_put(aead);
+	return rc;
+}
+
+/**
+ * tipc_crypto_rcv - Decrypt an encrypted TIPC message from peer
+ * @net: struct net
+ * @rx: RX crypto handle
+ * @skb: input/output message skb pointer
+ * @b: bearer where the message has been received
+ *
+ * If the decryption is successful, the decrypted skb is returned directly or
+ * as the callback, the encryption header and auth tag will be trimed out
+ * before forwarding to tipc_rcv() via the tipc_crypto_rcv_complete().
+ * Otherwise, the skb will be freed!
+ * Note: RX key(s) can be re-aligned, or in case of no key suitable, TX
+ * cluster key(s) can be taken for decryption (- recursive).
+ *
+ * Return:
+ * 0                   : the decryption has successfully completed
+ * -EINPROGRESS/-EBUSY : the decryption is ongoing, a callback will be made
+ * -ENOKEY             : the decryption has failed due to no key
+ * -EBADMSG            : the decryption has failed due to bad message
+ * -ENOMEM             : the decryption has failed due to no memory
+ * < 0                 : the decryption has failed due to other reasons
+ */
+int tipc_crypto_rcv(struct net *net, struct tipc_crypto *rx,
+		    struct sk_buff **skb, struct tipc_bearer *b)
+{
+	struct tipc_crypto *tx = tipc_net(net)->crypto_tx;
+	struct tipc_crypto_stats __percpu *stats;
+	struct tipc_aead *aead = NULL;
+	struct tipc_key key;
+	int rc = -ENOKEY;
+	u8 tx_key, n;
+
+	tx_key = ((struct tipc_ehdr *)(*skb)->data)->tx_key;
+
+	/* New peer?
+	 * Let's try with TX key (i.e. cluster mode) & verify the skb first!
+	 */
+	if (unlikely(!rx || tx_key == KEY_MASTER))
+		goto pick_tx;
+
+	/* Pick RX key according to TX key if any */
+	key = rx->key;
+	if (tx_key == key.active || tx_key == key.pending ||
+	    tx_key == key.passive)
+		goto decrypt;
+
+	/* Unknown key, let's try to align RX key(s) */
+	if (tipc_crypto_key_try_align(rx, tx_key))
+		goto decrypt;
+
+pick_tx:
+	/* No key suitable? Try to pick one from TX... */
+	aead = tipc_crypto_key_pick_tx(tx, rx, *skb, tx_key);
+	if (aead)
+		goto decrypt;
+	goto exit;
+
+decrypt:
+	rcu_read_lock();
+	if (!aead)
+		aead = tipc_aead_get(rx->aead[tx_key]);
+	rc = tipc_aead_decrypt(net, aead, *skb, b);
+	rcu_read_unlock();
+
+exit:
+	stats = ((rx) ?: tx)->stats;
+	switch (rc) {
+	case 0:
+		this_cpu_inc(stats->stat[STAT_OK]);
+		break;
+	case -EINPROGRESS:
+	case -EBUSY:
+		this_cpu_inc(stats->stat[STAT_ASYNC]);
+		*skb = NULL;
+		return rc;
+	default:
+		this_cpu_inc(stats->stat[STAT_NOK]);
+		if (rc == -ENOKEY) {
+			kfree_skb(*skb);
+			*skb = NULL;
+			if (rx) {
+				/* Mark rx->nokey only if we dont have a
+				 * pending received session key, nor a newer
+				 * one i.e. in the next slot.
+				 */
+				n = key_next(tx_key);
+				rx->nokey = !(rx->skey ||
+					      rcu_access_pointer(rx->aead[n]));
+				pr_debug_ratelimited("%s: nokey %d, key %d/%x\n",
+						     rx->name, rx->nokey,
+						     tx_key, rx->key.keys);
+				tipc_node_put(rx->node);
+			}
+			this_cpu_inc(stats->stat[STAT_NOKEYS]);
+			return rc;
+		} else if (rc == -EBADMSG) {
+			this_cpu_inc(stats->stat[STAT_BADMSGS]);
+		}
+		break;
+	}
+
+	tipc_crypto_rcv_complete(net, aead, b, skb, rc);
+	return rc;
+}
+
+static void tipc_crypto_rcv_complete(struct net *net, struct tipc_aead *aead,
+				     struct tipc_bearer *b,
+				     struct sk_buff **skb, int err)
+{
+	struct tipc_skb_cb *skb_cb = TIPC_SKB_CB(*skb);
+	struct tipc_crypto *rx = aead->crypto;
+	struct tipc_aead *tmp = NULL;
+	struct tipc_ehdr *ehdr;
+	struct tipc_node *n;
+
+	/* Is this completed by TX? */
+	if (unlikely(is_tx(aead->crypto))) {
+		rx = skb_cb->tx_clone_ctx.rx;
+		pr_debug("TX->RX(%s): err %d, aead %p, skb->next %p, flags %x\n",
+			 (rx) ? tipc_node_get_id_str(rx->node) : "-", err, aead,
+			 (*skb)->next, skb_cb->flags);
+		pr_debug("skb_cb [recurs %d, last %p], tx->aead [%p %p %p]\n",
+			 skb_cb->tx_clone_ctx.recurs, skb_cb->tx_clone_ctx.last,
+			 aead->crypto->aead[1], aead->crypto->aead[2],
+			 aead->crypto->aead[3]);
+		if (unlikely(err)) {
+			if (err == -EBADMSG && (*skb)->next)
+				tipc_rcv(net, (*skb)->next, b);
+			goto free_skb;
+		}
+
+		if (likely((*skb)->next)) {
+			kfree_skb((*skb)->next);
+			(*skb)->next = NULL;
+		}
+		ehdr = (struct tipc_ehdr *)(*skb)->data;
+		if (!rx) {
+			WARN_ON(ehdr->user != LINK_CONFIG);
+			n = tipc_node_create(net, 0, ehdr->id, 0xffffu, 0,
+					     true);
+			rx = tipc_node_crypto_rx(n);
+			if (unlikely(!rx))
+				goto free_skb;
+		}
+
+		/* Ignore cloning if it was TX master key */
+		if (ehdr->tx_key == KEY_MASTER)
+			goto rcv;
+		if (tipc_aead_clone(&tmp, aead) < 0)
+			goto rcv;
+		WARN_ON(!refcount_inc_not_zero(&tmp->refcnt));
+		if (tipc_crypto_key_attach(rx, tmp, ehdr->tx_key, false) < 0) {
+			tipc_aead_free(&tmp->rcu);
+			goto rcv;
+		}
+		tipc_aead_put(aead);
+		aead = tmp;
+	}
+
+	if (unlikely(err)) {
+		tipc_aead_users_dec(aead, INT_MIN);
+		goto free_skb;
+	}
+
+	/* Set the RX key's user */
+	tipc_aead_users_set(aead, 1);
+
+	/* Mark this point, RX works */
+	rx->timer1 = jiffies;
+
+rcv:
+	/* Remove ehdr & auth. tag prior to tipc_rcv() */
+	ehdr = (struct tipc_ehdr *)(*skb)->data;
+
+	/* Mark this point, RX passive still works */
+	if (rx->key.passive && ehdr->tx_key == rx->key.passive)
+		rx->timer2 = jiffies;
+
+	skb_reset_network_header(*skb);
+	skb_pull(*skb, tipc_ehdr_size(ehdr));
+	if (pskb_trim(*skb, (*skb)->len - aead->authsize))
+		goto free_skb;
+
+	/* Validate TIPCv2 message */
+	if (unlikely(!tipc_msg_validate(skb))) {
+		pr_err_ratelimited("Packet dropped after decryption!\n");
+		goto free_skb;
+	}
+
+	/* Ok, everything's fine, try to synch own keys according to peers' */
+	tipc_crypto_key_synch(rx, *skb);
+
+	/* Re-fetch skb cb as skb might be changed in tipc_msg_validate */
+	skb_cb = TIPC_SKB_CB(*skb);
+
+	/* Mark skb decrypted */
+	skb_cb->decrypted = 1;
+
+	/* Clear clone cxt if any */
+	if (likely(!skb_cb->tx_clone_deferred))
+		goto exit;
+	skb_cb->tx_clone_deferred = 0;
+	memset(&skb_cb->tx_clone_ctx, 0, sizeof(skb_cb->tx_clone_ctx));
+	goto exit;
+
+free_skb:
+	kfree_skb(*skb);
+	*skb = NULL;
+
+exit:
+	tipc_aead_put(aead);
+	if (rx)
+		tipc_node_put(rx->node);
+}
+
+static void tipc_crypto_do_cmd(struct net *net, int cmd)
+{
+	struct tipc_net *tn = tipc_net(net);
+	struct tipc_crypto *tx = tn->crypto_tx, *rx;
+	struct list_head *p;
+	unsigned int stat;
+	int i, j, cpu;
+	char buf[200];
+
+	/* Currently only one command is supported */
+	switch (cmd) {
+	case 0xfff1:
+		goto print_stats;
+	default:
+		return;
+	}
+
+print_stats:
+	/* Print a header */
+	pr_info("\n=============== TIPC Crypto Statistics ===============\n\n");
+
+	/* Print key status */
+	pr_info("Key status:\n");
+	pr_info("TX(%7.7s)\n%s", tipc_own_id_string(net),
+		tipc_crypto_key_dump(tx, buf));
+
+	rcu_read_lock();
+	for (p = tn->node_list.next; p != &tn->node_list; p = p->next) {
+		rx = tipc_node_crypto_rx_by_list(p);
+		pr_info("RX(%7.7s)\n%s", tipc_node_get_id_str(rx->node),
+			tipc_crypto_key_dump(rx, buf));
+	}
+	rcu_read_unlock();
+
+	/* Print crypto statistics */
+	for (i = 0, j = 0; i < MAX_STATS; i++)
+		j += scnprintf(buf + j, 200 - j, "|%11s ", hstats[i]);
+	pr_info("Counter     %s", buf);
+
+	memset(buf, '-', 115);
+	buf[115] = '\0';
+	pr_info("%s\n", buf);
+
+	j = scnprintf(buf, 200, "TX(%7.7s) ", tipc_own_id_string(net));
+	for_each_possible_cpu(cpu) {
+		for (i = 0; i < MAX_STATS; i++) {
+			stat = per_cpu_ptr(tx->stats, cpu)->stat[i];
+			j += scnprintf(buf + j, 200 - j, "|%11d ", stat);
+		}
+		pr_info("%s", buf);
+		j = scnprintf(buf, 200, "%12s", " ");
+	}
+
+	rcu_read_lock();
+	for (p = tn->node_list.next; p != &tn->node_list; p = p->next) {
+		rx = tipc_node_crypto_rx_by_list(p);
+		j = scnprintf(buf, 200, "RX(%7.7s) ",
+			      tipc_node_get_id_str(rx->node));
+		for_each_possible_cpu(cpu) {
+			for (i = 0; i < MAX_STATS; i++) {
+				stat = per_cpu_ptr(rx->stats, cpu)->stat[i];
+				j += scnprintf(buf + j, 200 - j, "|%11d ",
+					       stat);
+			}
+			pr_info("%s", buf);
+			j = scnprintf(buf, 200, "%12s", " ");
+		}
+	}
+	rcu_read_unlock();
+
+	pr_info("\n======================== Done ========================\n");
+}
+
+static char *tipc_crypto_key_dump(struct tipc_crypto *c, char *buf)
+{
+	struct tipc_key key = c->key;
+	struct tipc_aead *aead;
+	int k, i = 0;
+	char *s;
+
+	for (k = KEY_MIN; k <= KEY_MAX; k++) {
+		if (k == KEY_MASTER) {
+			if (is_rx(c))
+				continue;
+			if (time_before(jiffies,
+					c->timer2 + TIPC_TX_GRACE_PERIOD))
+				s = "ACT";
+			else
+				s = "PAS";
+		} else {
+			if (k == key.passive)
+				s = "PAS";
+			else if (k == key.active)
+				s = "ACT";
+			else if (k == key.pending)
+				s = "PEN";
+			else
+				s = "-";
+		}
+		i += scnprintf(buf + i, 200 - i, "\tKey%d: %s", k, s);
+
+		rcu_read_lock();
+		aead = rcu_dereference(c->aead[k]);
+		if (aead)
+			i += scnprintf(buf + i, 200 - i,
+				       "{\"0x...%s\", \"%s\"}/%d:%d",
+				       aead->hint,
+				       (aead->mode == CLUSTER_KEY) ? "c" : "p",
+				       atomic_read(&aead->users),
+				       refcount_read(&aead->refcnt));
+		rcu_read_unlock();
+		i += scnprintf(buf + i, 200 - i, "\n");
+	}
+
+	if (is_rx(c))
+		i += scnprintf(buf + i, 200 - i, "\tPeer RX active: %d\n",
+			       atomic_read(&c->peer_rx_active));
+
+	return buf;
+}
+
+static char *tipc_key_change_dump(struct tipc_key old, struct tipc_key new,
+				  char *buf)
+{
+	struct tipc_key *key = &old;
+	int k, i = 0;
+	char *s;
+
+	/* Output format: "[%s %s %s] -> [%s %s %s]", max len = 32 */
+again:
+	i += scnprintf(buf + i, 32 - i, "[");
+	for (k = KEY_1; k <= KEY_3; k++) {
+		if (k == key->passive)
+			s = "pas";
+		else if (k == key->active)
+			s = "act";
+		else if (k == key->pending)
+			s = "pen";
+		else
+			s = "-";
+		i += scnprintf(buf + i, 32 - i,
+			       (k != KEY_3) ? "%s " : "%s", s);
+	}
+	if (key != &new) {
+		i += scnprintf(buf + i, 32 - i, "] -> ");
+		key = &new;
+		goto again;
+	}
+	i += scnprintf(buf + i, 32 - i, "]");
+	return buf;
+}
+
+/**
+ * tipc_crypto_msg_rcv - Common 'MSG_CRYPTO' processing point
+ * @net: the struct net
+ * @skb: the receiving message buffer
+ */
+void tipc_crypto_msg_rcv(struct net *net, struct sk_buff *skb)
+{
+	struct tipc_crypto *rx;
+	struct tipc_msg *hdr;
+
+	if (unlikely(skb_linearize(skb)))
+		goto exit;
+
+	hdr = buf_msg(skb);
+	rx = tipc_node_crypto_rx_by_addr(net, msg_prevnode(hdr));
+	if (unlikely(!rx))
+		goto exit;
+
+	switch (msg_type(hdr)) {
+	case KEY_DISTR_MSG:
+		if (tipc_crypto_key_rcv(rx, hdr))
+			goto exit;
+		break;
+	default:
+		break;
+	}
+
+	tipc_node_put(rx->node);
+
+exit:
+	kfree_skb(skb);
+}
+
+/**
+ * tipc_crypto_key_distr - Distribute a TX key
+ * @tx: the TX crypto
+ * @key: the key's index
+ * @dest: the destination tipc node, = NULL if distributing to all nodes
+ *
+ * Return: 0 in case of success, otherwise < 0
+ */
+int tipc_crypto_key_distr(struct tipc_crypto *tx, u8 key,
+			  struct tipc_node *dest)
+{
+	struct tipc_aead *aead;
+	u32 dnode = tipc_node_get_addr(dest);
+	int rc = -ENOKEY;
+
+	if (!sysctl_tipc_key_exchange_enabled)
+		return 0;
+
+	if (key) {
+		rcu_read_lock();
+		aead = tipc_aead_get(tx->aead[key]);
+		if (likely(aead)) {
+			rc = tipc_crypto_key_xmit(tx->net, aead->key,
+						  aead->gen, aead->mode,
+						  dnode);
+			tipc_aead_put(aead);
+		}
+		rcu_read_unlock();
+	}
+
+	return rc;
+}
+
+/**
+ * tipc_crypto_key_xmit - Send a session key
+ * @net: the struct net
+ * @skey: the session key to be sent
+ * @gen: the key's generation
+ * @mode: the key's mode
+ * @dnode: the destination node address, = 0 if broadcasting to all nodes
+ *
+ * The session key 'skey' is packed in a TIPC v2 'MSG_CRYPTO/KEY_DISTR_MSG'
+ * as its data section, then xmit-ed through the uc/bc link.
+ *
+ * Return: 0 in case of success, otherwise < 0
+ */
+static int tipc_crypto_key_xmit(struct net *net, struct tipc_aead_key *skey,
+				u16 gen, u8 mode, u32 dnode)
+{
+	struct sk_buff_head pkts;
+	struct tipc_msg *hdr;
+	struct sk_buff *skb;
+	u16 size, cong_link_cnt;
+	u8 *data;
+	int rc;
+
+	size = tipc_aead_key_size(skey);
+	skb = tipc_buf_acquire(INT_H_SIZE + size, GFP_ATOMIC);
+	if (!skb)
+		return -ENOMEM;
+
+	hdr = buf_msg(skb);
+	tipc_msg_init(tipc_own_addr(net), hdr, MSG_CRYPTO, KEY_DISTR_MSG,
+		      INT_H_SIZE, dnode);
+	msg_set_size(hdr, INT_H_SIZE + size);
+	msg_set_key_gen(hdr, gen);
+	msg_set_key_mode(hdr, mode);
+
+	data = msg_data(hdr);
+	*((__be32 *)(data + TIPC_AEAD_ALG_NAME)) = htonl(skey->keylen);
+	memcpy(data, skey->alg_name, TIPC_AEAD_ALG_NAME);
+	memcpy(data + TIPC_AEAD_ALG_NAME + sizeof(__be32), skey->key,
+	       skey->keylen);
+
+	__skb_queue_head_init(&pkts);
+	__skb_queue_tail(&pkts, skb);
+	if (dnode)
+		rc = tipc_node_xmit(net, &pkts, dnode, 0);
+	else
+		rc = tipc_bcast_xmit(net, &pkts, &cong_link_cnt);
+
+	return rc;
+}
+
+/**
+ * tipc_crypto_key_rcv - Receive a session key
+ * @rx: the RX crypto
+ * @hdr: the TIPC v2 message incl. the receiving session key in its data
+ *
+ * This function retrieves the session key in the message from peer, then
+ * schedules a RX work to attach the key to the corresponding RX crypto.
+ *
+ * Return: "true" if the key has been scheduled for attaching, otherwise
+ * "false".
+ */
+static bool tipc_crypto_key_rcv(struct tipc_crypto *rx, struct tipc_msg *hdr)
+{
+	struct tipc_crypto *tx = tipc_net(rx->net)->crypto_tx;
+	struct tipc_aead_key *skey = NULL;
+	u16 key_gen = msg_key_gen(hdr);
+	u32 size = msg_data_sz(hdr);
+	u8 *data = msg_data(hdr);
+	unsigned int keylen;
+
+	/* Verify whether the size can exist in the packet */
+	if (unlikely(size < sizeof(struct tipc_aead_key) + TIPC_AEAD_KEYLEN_MIN)) {
+		pr_debug("%s: message data size is too small\n", rx->name);
+		goto exit;
+	}
+
+	keylen = ntohl(*((__be32 *)(data + TIPC_AEAD_ALG_NAME)));
+
+	/* Verify the supplied size values */
+	if (unlikely(size != keylen + sizeof(struct tipc_aead_key) ||
+		     keylen > TIPC_AEAD_KEY_SIZE_MAX)) {
+		pr_debug("%s: invalid MSG_CRYPTO key size\n", rx->name);
+		goto exit;
+	}
+
+	spin_lock(&rx->lock);
+	if (unlikely(rx->skey || (key_gen == rx->key_gen && rx->key.keys))) {
+		pr_err("%s: key existed <%p>, gen %d vs %d\n", rx->name,
+		       rx->skey, key_gen, rx->key_gen);
+		goto exit_unlock;
+	}
+
+	/* Allocate memory for the key */
+	skey = kmalloc(size, GFP_ATOMIC);
+	if (unlikely(!skey)) {
+		pr_err("%s: unable to allocate memory for skey\n", rx->name);
+		goto exit_unlock;
+	}
+
+	/* Copy key from msg data */
+	skey->keylen = keylen;
+	memcpy(skey->alg_name, data, TIPC_AEAD_ALG_NAME);
+	memcpy(skey->key, data + TIPC_AEAD_ALG_NAME + sizeof(__be32),
+	       skey->keylen);
+
+	rx->key_gen = key_gen;
+	rx->skey_mode = msg_key_mode(hdr);
+	rx->skey = skey;
+	rx->nokey = 0;
+	mb(); /* for nokey flag */
+
+exit_unlock:
+	spin_unlock(&rx->lock);
+
+exit:
+	/* Schedule the key attaching on this crypto */
+	if (likely(skey && queue_delayed_work(tx->wq, &rx->work, 0)))
+		return true;
+
+	return false;
+}
+
+/**
+ * tipc_crypto_work_rx - Scheduled RX works handler
+ * @work: the struct RX work
+ *
+ * The function processes the previous scheduled works i.e. distributing TX key
+ * or attaching a received session key on RX crypto.
+ */
+static void tipc_crypto_work_rx(struct work_struct *work)
+{
+	struct delayed_work *dwork = to_delayed_work(work);
+	struct tipc_crypto *rx = container_of(dwork, struct tipc_crypto, work);
+	struct tipc_crypto *tx = tipc_net(rx->net)->crypto_tx;
+	unsigned long delay = msecs_to_jiffies(5000);
+	bool resched = false;
+	u8 key;
+	int rc;
+
+	/* Case 1: Distribute TX key to peer if scheduled */
+	if (atomic_cmpxchg(&rx->key_distr,
+			   KEY_DISTR_SCHED,
+			   KEY_DISTR_COMPL) == KEY_DISTR_SCHED) {
+		/* Always pick the newest one for distributing */
+		key = tx->key.pending ?: tx->key.active;
+		rc = tipc_crypto_key_distr(tx, key, rx->node);
+		if (unlikely(rc))
+			pr_warn("%s: unable to distr key[%d] to %s, err %d\n",
+				tx->name, key, tipc_node_get_id_str(rx->node),
+				rc);
+
+		/* Sched for key_distr releasing */
+		resched = true;
+	} else {
+		atomic_cmpxchg(&rx->key_distr, KEY_DISTR_COMPL, 0);
+	}
+
+	/* Case 2: Attach a pending received session key from peer if any */
+	if (rx->skey) {
+		rc = tipc_crypto_key_init(rx, rx->skey, rx->skey_mode, false);
+		if (unlikely(rc < 0))
+			pr_warn("%s: unable to attach received skey, err %d\n",
+				rx->name, rc);
+		switch (rc) {
+		case -EBUSY:
+		case -ENOMEM:
+			/* Resched the key attaching */
+			resched = true;
+			break;
+		default:
+			synchronize_rcu();
+			kfree(rx->skey);
+			rx->skey = NULL;
+			break;
+		}
+	}
+
+	if (resched && queue_delayed_work(tx->wq, &rx->work, delay))
+		return;
+
+	tipc_node_put(rx->node);
+}
+
+/**
+ * tipc_crypto_rekeying_sched - (Re)schedule rekeying w/o new interval
+ * @tx: TX crypto
+ * @changed: if the rekeying needs to be rescheduled with new interval
+ * @new_intv: new rekeying interval (when "changed" = true)
+ */
+void tipc_crypto_rekeying_sched(struct tipc_crypto *tx, bool changed,
+				u32 new_intv)
+{
+	unsigned long delay;
+	bool now = false;
+
+	if (changed) {
+		if (new_intv == TIPC_REKEYING_NOW)
+			now = true;
+		else
+			tx->rekeying_intv = new_intv;
+		cancel_delayed_work_sync(&tx->work);
+	}
+
+	if (tx->rekeying_intv || now) {
+		delay = (now) ? 0 : tx->rekeying_intv * 60 * 1000;
+		queue_delayed_work(tx->wq, &tx->work, msecs_to_jiffies(delay));
+	}
+}
+
+/**
+ * tipc_crypto_work_tx - Scheduled TX works handler
+ * @work: the struct TX work
+ *
+ * The function processes the previous scheduled work, i.e. key rekeying, by
+ * generating a new session key based on current one, then attaching it to the
+ * TX crypto and finally distributing it to peers. It also re-schedules the
+ * rekeying if needed.
+ */
+static void tipc_crypto_work_tx(struct work_struct *work)
+{
+	struct delayed_work *dwork = to_delayed_work(work);
+	struct tipc_crypto *tx = container_of(dwork, struct tipc_crypto, work);
+	struct tipc_aead_key *skey = NULL;
+	struct tipc_key key = tx->key;
+	struct tipc_aead *aead;
+	int rc = -ENOMEM;
+
+	if (unlikely(key.pending))
+		goto resched;
+
+	/* Take current key as a template */
+	rcu_read_lock();
+	aead = rcu_dereference(tx->aead[key.active ?: KEY_MASTER]);
+	if (unlikely(!aead)) {
+		rcu_read_unlock();
+		/* At least one key should exist for securing */
+		return;
+	}
+
+	/* Lets duplicate it first */
+	skey = kmemdup(aead->key, tipc_aead_key_size(aead->key), GFP_ATOMIC);
+	rcu_read_unlock();
+
+	/* Now, generate new key, initiate & distribute it */
+	if (likely(skey)) {
+		rc = tipc_aead_key_generate(skey) ?:
+		     tipc_crypto_key_init(tx, skey, PER_NODE_KEY, false);
+		if (likely(rc > 0))
+			rc = tipc_crypto_key_distr(tx, rc, NULL);
+		kfree_sensitive(skey);
+	}
+
+	if (unlikely(rc))
+		pr_warn_ratelimited("%s: rekeying returns %d\n", tx->name, rc);
+
+resched:
+	/* Re-schedule rekeying if any */
+	tipc_crypto_rekeying_sched(tx, false, 0);
+}