1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * net/tipc/crypto.c: TIPC crypto for key handling & packet en/decryption
   4 *
   5 * Copyright (c) 2019, Ericsson AB
   6 * All rights reserved.
   7 *
   8 * Redistribution and use in source and binary forms, with or without
   9 * modification, are permitted provided that the following conditions are met:
  10 *
  11 * 1. Redistributions of source code must retain the above copyright
  12 *    notice, this list of conditions and the following disclaimer.
  13 * 2. Redistributions in binary form must reproduce the above copyright
  14 *    notice, this list of conditions and the following disclaimer in the
  15 *    documentation and/or other materials provided with the distribution.
  16 * 3. Neither the names of the copyright holders nor the names of its
  17 *    contributors may be used to endorse or promote products derived from
  18 *    this software without specific prior written permission.
  19 *
  20 * Alternatively, this software may be distributed under the terms of the
  21 * GNU General Public License ("GPL") version 2 as published by the Free
  22 * Software Foundation.
  23 *
  24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  25 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  28 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  32 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  33 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  34 * POSSIBILITY OF SUCH DAMAGE.
  35 */
  36
  37#include <crypto/aead.h>
  38#include <crypto/aes.h>
  39#include <crypto/rng.h>
  40#include "crypto.h"
  41#include "msg.h"
  42#include "bcast.h"
  43
  44#define TIPC_TX_GRACE_PERIOD	msecs_to_jiffies(5000) /* 5s */
  45#define TIPC_TX_LASTING_TIME	msecs_to_jiffies(10000) /* 10s */
  46#define TIPC_RX_ACTIVE_LIM	msecs_to_jiffies(3000) /* 3s */
  47#define TIPC_RX_PASSIVE_LIM	msecs_to_jiffies(15000) /* 15s */
  48
  49#define TIPC_MAX_TFMS_DEF	10
  50#define TIPC_MAX_TFMS_LIM	1000
  51
  52#define TIPC_REKEYING_INTV_DEF	(60 * 24) /* default: 1 day */
  53
  54/*
  55 * TIPC Key ids
  56 */
  57enum {
  58	KEY_MASTER = 0,
  59	KEY_MIN = KEY_MASTER,
  60	KEY_1 = 1,
  61	KEY_2,
  62	KEY_3,
  63	KEY_MAX = KEY_3,
  64};
  65
  66/*
  67 * TIPC Crypto statistics
  68 */
  69enum {
  70	STAT_OK,
  71	STAT_NOK,
  72	STAT_ASYNC,
  73	STAT_ASYNC_OK,
  74	STAT_ASYNC_NOK,
  75	STAT_BADKEYS, /* tx only */
  76	STAT_BADMSGS = STAT_BADKEYS, /* rx only */
  77	STAT_NOKEYS,
  78	STAT_SWITCHES,
  79
  80	MAX_STATS,
  81};
  82
  83/* TIPC crypto statistics' header */
  84static const char *hstats[MAX_STATS] = {"ok", "nok", "async", "async_ok",
  85					"async_nok", "badmsgs", "nokeys",
  86					"switches"};
  87
  88/* Max TFMs number per key */
  89int sysctl_tipc_max_tfms __read_mostly = TIPC_MAX_TFMS_DEF;
  90/* Key exchange switch, default: on */
  91int sysctl_tipc_key_exchange_enabled __read_mostly = 1;
  92
  93/*
  94 * struct tipc_key - TIPC keys' status indicator
  95 *
  96 *         7     6     5     4     3     2     1     0
  97 *      +-----+-----+-----+-----+-----+-----+-----+-----+
  98 * key: | (reserved)|passive idx| active idx|pending idx|
  99 *      +-----+-----+-----+-----+-----+-----+-----+-----+
 100 */
 101struct tipc_key {
 102#define KEY_BITS (2)
 103#define KEY_MASK ((1 << KEY_BITS) - 1)
 104	union {
 105		struct {
 106#if defined(__LITTLE_ENDIAN_BITFIELD)
 107			u8 pending:2,
 108			   active:2,
 109			   passive:2, /* rx only */
 110			   reserved:2;
 111#elif defined(__BIG_ENDIAN_BITFIELD)
 112			u8 reserved:2,
 113			   passive:2, /* rx only */
 114			   active:2,
 115			   pending:2;
 116#else
 117#error  "Please fix <asm/byteorder.h>"
 118#endif
 119		} __packed;
 120		u8 keys;
 121	};
 122};
 123
 124/**
 125 * struct tipc_tfm - TIPC TFM structure to form a list of TFMs
 126 * @tfm: cipher handle/key
 127 * @list: linked list of TFMs
 128 */
 129struct tipc_tfm {
 130	struct crypto_aead *tfm;
 131	struct list_head list;
 132};
 133
 134/**
 135 * struct tipc_aead - TIPC AEAD key structure
 136 * @tfm_entry: per-cpu pointer to one entry in TFM list
 137 * @crypto: TIPC crypto owns this key
 138 * @cloned: reference to the source key in case cloning
 139 * @users: the number of the key users (TX/RX)
 140 * @salt: the key's SALT value
 141 * @authsize: authentication tag size (max = 16)
 142 * @mode: crypto mode is applied to the key
 143 * @hint: a hint for user key
 144 * @rcu: struct rcu_head
 145 * @key: the aead key
 146 * @gen: the key's generation
 147 * @seqno: the key seqno (cluster scope)
 148 * @refcnt: the key reference counter
 149 */
 150struct tipc_aead {
 151#define TIPC_AEAD_HINT_LEN (5)
 152	struct tipc_tfm * __percpu *tfm_entry;
 153	struct tipc_crypto *crypto;
 154	struct tipc_aead *cloned;
 155	atomic_t users;
 156	u32 salt;
 157	u8 authsize;
 158	u8 mode;
 159	char hint[2 * TIPC_AEAD_HINT_LEN + 1];
 160	struct rcu_head rcu;
 161	struct tipc_aead_key *key;
 162	u16 gen;
 163
 164	atomic64_t seqno ____cacheline_aligned;
 165	refcount_t refcnt ____cacheline_aligned;
 166
 167} ____cacheline_aligned;
 168
 169/**
 170 * struct tipc_crypto_stats - TIPC Crypto statistics
 171 * @stat: array of crypto statistics
 172 */
 173struct tipc_crypto_stats {
 174	unsigned int stat[MAX_STATS];
 175};
 176
 177/**
 178 * struct tipc_crypto - TIPC TX/RX crypto structure
 179 * @net: struct net
 180 * @node: TIPC node (RX)
 181 * @aead: array of pointers to AEAD keys for encryption/decryption
 182 * @peer_rx_active: replicated peer RX active key index
 183 * @key_gen: TX/RX key generation
 184 * @key: the key states
 185 * @skey_mode: session key's mode
 186 * @skey: received session key
 187 * @wq: common workqueue on TX crypto
 188 * @work: delayed work sched for TX/RX
 189 * @key_distr: key distributing state
 190 * @rekeying_intv: rekeying interval (in minutes)
 191 * @stats: the crypto statistics
 192 * @name: the crypto name
 193 * @sndnxt: the per-peer sndnxt (TX)
 194 * @timer1: general timer 1 (jiffies)
 195 * @timer2: general timer 2 (jiffies)
 196 * @working: the crypto is working or not
 197 * @key_master: flag indicates if master key exists
 198 * @legacy_user: flag indicates if a peer joins w/o master key (for bwd comp.)
 199 * @nokey: no key indication
 200 * @flags: combined flags field
 201 * @lock: tipc_key lock
 202 */
 203struct tipc_crypto {
 204	struct net *net;
 205	struct tipc_node *node;
 206	struct tipc_aead __rcu *aead[KEY_MAX + 1];
 207	atomic_t peer_rx_active;
 208	u16 key_gen;
 209	struct tipc_key key;
 210	u8 skey_mode;
 211	struct tipc_aead_key *skey;
 212	struct workqueue_struct *wq;
 213	struct delayed_work work;
 214#define KEY_DISTR_SCHED		1
 215#define KEY_DISTR_COMPL		2
 216	atomic_t key_distr;
 217	u32 rekeying_intv;
 218
 219	struct tipc_crypto_stats __percpu *stats;
 220	char name[48];
 221
 222	atomic64_t sndnxt ____cacheline_aligned;
 223	unsigned long timer1;
 224	unsigned long timer2;
 225	union {
 226		struct {
 227			u8 working:1;
 228			u8 key_master:1;
 229			u8 legacy_user:1;
 230			u8 nokey: 1;
 231		};
 232		u8 flags;
 233	};
 234	spinlock_t lock; /* crypto lock */
 235
 236} ____cacheline_aligned;
 237
 238/* struct tipc_crypto_tx_ctx - TX context for callbacks */
 239struct tipc_crypto_tx_ctx {
 240	struct tipc_aead *aead;
 241	struct tipc_bearer *bearer;
 242	struct tipc_media_addr dst;
 243};
 244
 245/* struct tipc_crypto_rx_ctx - RX context for callbacks */
 246struct tipc_crypto_rx_ctx {
 247	struct tipc_aead *aead;
 248	struct tipc_bearer *bearer;
 249};
 250
 251static struct tipc_aead *tipc_aead_get(struct tipc_aead __rcu *aead);
 252static inline void tipc_aead_put(struct tipc_aead *aead);
 253static void tipc_aead_free(struct rcu_head *rp);
 254static int tipc_aead_users(struct tipc_aead __rcu *aead);
 255static void tipc_aead_users_inc(struct tipc_aead __rcu *aead, int lim);
 256static void tipc_aead_users_dec(struct tipc_aead __rcu *aead, int lim);
 257static void tipc_aead_users_set(struct tipc_aead __rcu *aead, int val);
 258static struct crypto_aead *tipc_aead_tfm_next(struct tipc_aead *aead);
 259static int tipc_aead_init(struct tipc_aead **aead, struct tipc_aead_key *ukey,
 260			  u8 mode);
 261static int tipc_aead_clone(struct tipc_aead **dst, struct tipc_aead *src);
 262static void *tipc_aead_mem_alloc(struct crypto_aead *tfm,
 263				 unsigned int crypto_ctx_size,
 264				 u8 **iv, struct aead_request **req,
 265				 struct scatterlist **sg, int nsg);
 266static int tipc_aead_encrypt(struct tipc_aead *aead, struct sk_buff *skb,
 267			     struct tipc_bearer *b,
 268			     struct tipc_media_addr *dst,
 269			     struct tipc_node *__dnode);
 270static void tipc_aead_encrypt_done(struct crypto_async_request *base, int err);
 271static int tipc_aead_decrypt(struct net *net, struct tipc_aead *aead,
 272			     struct sk_buff *skb, struct tipc_bearer *b);
 273static void tipc_aead_decrypt_done(struct crypto_async_request *base, int err);
 274static inline int tipc_ehdr_size(struct tipc_ehdr *ehdr);
 275static int tipc_ehdr_build(struct net *net, struct tipc_aead *aead,
 276			   u8 tx_key, struct sk_buff *skb,
 277			   struct tipc_crypto *__rx);
 278static inline void tipc_crypto_key_set_state(struct tipc_crypto *c,
 279					     u8 new_passive,
 280					     u8 new_active,
 281					     u8 new_pending);
 282static int tipc_crypto_key_attach(struct tipc_crypto *c,
 283				  struct tipc_aead *aead, u8 pos,
 284				  bool master_key);
 285static bool tipc_crypto_key_try_align(struct tipc_crypto *rx, u8 new_pending);
 286static struct tipc_aead *tipc_crypto_key_pick_tx(struct tipc_crypto *tx,
 287						 struct tipc_crypto *rx,
 288						 struct sk_buff *skb,
 289						 u8 tx_key);
 290static void tipc_crypto_key_synch(struct tipc_crypto *rx, struct sk_buff *skb);
 291static int tipc_crypto_key_revoke(struct net *net, u8 tx_key);
 292static inline void tipc_crypto_clone_msg(struct net *net, struct sk_buff *_skb,
 293					 struct tipc_bearer *b,
 294					 struct tipc_media_addr *dst,
 295					 struct tipc_node *__dnode, u8 type);
 296static void tipc_crypto_rcv_complete(struct net *net, struct tipc_aead *aead,
 297				     struct tipc_bearer *b,
 298				     struct sk_buff **skb, int err);
 299static void tipc_crypto_do_cmd(struct net *net, int cmd);
 300static char *tipc_crypto_key_dump(struct tipc_crypto *c, char *buf);
 
 301static char *tipc_key_change_dump(struct tipc_key old, struct tipc_key new,
 302				  char *buf);
 303static int tipc_crypto_key_xmit(struct net *net, struct tipc_aead_key *skey,
 304				u16 gen, u8 mode, u32 dnode);
 305static bool tipc_crypto_key_rcv(struct tipc_crypto *rx, struct tipc_msg *hdr);
 306static void tipc_crypto_work_tx(struct work_struct *work);
 307static void tipc_crypto_work_rx(struct work_struct *work);
 308static int tipc_aead_key_generate(struct tipc_aead_key *skey);
 309
 310#define is_tx(crypto) (!(crypto)->node)
 311#define is_rx(crypto) (!is_tx(crypto))
 312
 313#define key_next(cur) ((cur) % KEY_MAX + 1)
 314
 315#define tipc_aead_rcu_ptr(rcu_ptr, lock)				\
 316	rcu_dereference_protected((rcu_ptr), lockdep_is_held(lock))
 317
 318#define tipc_aead_rcu_replace(rcu_ptr, ptr, lock)			\
 319do {									\
 320	struct tipc_aead *__tmp = rcu_dereference_protected((rcu_ptr),	\
 321						lockdep_is_held(lock));	\
 322	rcu_assign_pointer((rcu_ptr), (ptr));				\
 323	tipc_aead_put(__tmp);						\
 324} while (0)
 325
 326#define tipc_crypto_key_detach(rcu_ptr, lock)				\
 327	tipc_aead_rcu_replace((rcu_ptr), NULL, lock)
 328
 329/**
 330 * tipc_aead_key_validate - Validate a AEAD user key
 331 * @ukey: pointer to user key data
 332 * @info: netlink info pointer
 333 */
 334int tipc_aead_key_validate(struct tipc_aead_key *ukey, struct genl_info *info)
 335{
 336	int keylen;
 337
 338	/* Check if algorithm exists */
 339	if (unlikely(!crypto_has_alg(ukey->alg_name, 0, 0))) {
 340		GENL_SET_ERR_MSG(info, "unable to load the algorithm (module existed?)");
 341		return -ENODEV;
 342	}
 343
 344	/* Currently, we only support the "gcm(aes)" cipher algorithm */
 345	if (strcmp(ukey->alg_name, "gcm(aes)")) {
 346		GENL_SET_ERR_MSG(info, "not supported yet the algorithm");
 347		return -ENOTSUPP;
 348	}
 349
 350	/* Check if key size is correct */
 351	keylen = ukey->keylen - TIPC_AES_GCM_SALT_SIZE;
 352	if (unlikely(keylen != TIPC_AES_GCM_KEY_SIZE_128 &&
 353		     keylen != TIPC_AES_GCM_KEY_SIZE_192 &&
 354		     keylen != TIPC_AES_GCM_KEY_SIZE_256)) {
 355		GENL_SET_ERR_MSG(info, "incorrect key length (20, 28 or 36 octets?)");
 356		return -EKEYREJECTED;
 357	}
 358
 359	return 0;
 360}
 361
 362/**
 363 * tipc_aead_key_generate - Generate new session key
 364 * @skey: input/output key with new content
 365 *
 366 * Return: 0 in case of success, otherwise < 0
 367 */
 368static int tipc_aead_key_generate(struct tipc_aead_key *skey)
 369{
 370	int rc = 0;
 371
 372	/* Fill the key's content with a random value via RNG cipher */
 373	rc = crypto_get_default_rng();
 374	if (likely(!rc)) {
 375		rc = crypto_rng_get_bytes(crypto_default_rng, skey->key,
 376					  skey->keylen);
 377		crypto_put_default_rng();
 378	}
 379
 380	return rc;
 381}
 382
 383static struct tipc_aead *tipc_aead_get(struct tipc_aead __rcu *aead)
 384{
 385	struct tipc_aead *tmp;
 386
 387	rcu_read_lock();
 388	tmp = rcu_dereference(aead);
 389	if (unlikely(!tmp || !refcount_inc_not_zero(&tmp->refcnt)))
 390		tmp = NULL;
 391	rcu_read_unlock();
 392
 393	return tmp;
 394}
 395
 396static inline void tipc_aead_put(struct tipc_aead *aead)
 397{
 398	if (aead && refcount_dec_and_test(&aead->refcnt))
 399		call_rcu(&aead->rcu, tipc_aead_free);
 400}
 401
 402/**
 403 * tipc_aead_free - Release AEAD key incl. all the TFMs in the list
 404 * @rp: rcu head pointer
 405 */
 406static void tipc_aead_free(struct rcu_head *rp)
 407{
 408	struct tipc_aead *aead = container_of(rp, struct tipc_aead, rcu);
 409	struct tipc_tfm *tfm_entry, *head, *tmp;
 410
 411	if (aead->cloned) {
 412		tipc_aead_put(aead->cloned);
 413	} else {
 414		head = *get_cpu_ptr(aead->tfm_entry);
 415		put_cpu_ptr(aead->tfm_entry);
 416		list_for_each_entry_safe(tfm_entry, tmp, &head->list, list) {
 417			crypto_free_aead(tfm_entry->tfm);
 418			list_del(&tfm_entry->list);
 419			kfree(tfm_entry);
 420		}
 421		/* Free the head */
 422		crypto_free_aead(head->tfm);
 423		list_del(&head->list);
 424		kfree(head);
 425	}
 426	free_percpu(aead->tfm_entry);
 427	kfree_sensitive(aead->key);
 428	kfree(aead);
 429}
 430
 431static int tipc_aead_users(struct tipc_aead __rcu *aead)
 432{
 433	struct tipc_aead *tmp;
 434	int users = 0;
 435
 436	rcu_read_lock();
 437	tmp = rcu_dereference(aead);
 438	if (tmp)
 439		users = atomic_read(&tmp->users);
 440	rcu_read_unlock();
 441
 442	return users;
 443}
 444
 445static void tipc_aead_users_inc(struct tipc_aead __rcu *aead, int lim)
 446{
 447	struct tipc_aead *tmp;
 448
 449	rcu_read_lock();
 450	tmp = rcu_dereference(aead);
 451	if (tmp)
 452		atomic_add_unless(&tmp->users, 1, lim);
 453	rcu_read_unlock();
 454}
 455
 456static void tipc_aead_users_dec(struct tipc_aead __rcu *aead, int lim)
 457{
 458	struct tipc_aead *tmp;
 459
 460	rcu_read_lock();
 461	tmp = rcu_dereference(aead);
 462	if (tmp)
 463		atomic_add_unless(&rcu_dereference(aead)->users, -1, lim);
 464	rcu_read_unlock();
 465}
 466
 467static void tipc_aead_users_set(struct tipc_aead __rcu *aead, int val)
 468{
 469	struct tipc_aead *tmp;
 470	int cur;
 471
 472	rcu_read_lock();
 473	tmp = rcu_dereference(aead);
 474	if (tmp) {
 475		do {
 476			cur = atomic_read(&tmp->users);
 477			if (cur == val)
 478				break;
 479		} while (atomic_cmpxchg(&tmp->users, cur, val) != cur);
 480	}
 481	rcu_read_unlock();
 482}
 483
 484/**
 485 * tipc_aead_tfm_next - Move TFM entry to the next one in list and return it
 486 * @aead: the AEAD key pointer
 487 */
 488static struct crypto_aead *tipc_aead_tfm_next(struct tipc_aead *aead)
 489{
 490	struct tipc_tfm **tfm_entry;
 491	struct crypto_aead *tfm;
 492
 493	tfm_entry = get_cpu_ptr(aead->tfm_entry);
 494	*tfm_entry = list_next_entry(*tfm_entry, list);
 495	tfm = (*tfm_entry)->tfm;
 496	put_cpu_ptr(tfm_entry);
 497
 498	return tfm;
 499}
 500
 501/**
 502 * tipc_aead_init - Initiate TIPC AEAD
 503 * @aead: returned new TIPC AEAD key handle pointer
 504 * @ukey: pointer to user key data
 505 * @mode: the key mode
 506 *
 507 * Allocate a (list of) new cipher transformation (TFM) with the specific user
 508 * key data if valid. The number of the allocated TFMs can be set via the sysfs
 509 * "net/tipc/max_tfms" first.
 510 * Also, all the other AEAD data are also initialized.
 511 *
 512 * Return: 0 if the initiation is successful, otherwise: < 0
 513 */
 514static int tipc_aead_init(struct tipc_aead **aead, struct tipc_aead_key *ukey,
 515			  u8 mode)
 516{
 517	struct tipc_tfm *tfm_entry, *head;
 518	struct crypto_aead *tfm;
 519	struct tipc_aead *tmp;
 520	int keylen, err, cpu;
 521	int tfm_cnt = 0;
 522
 523	if (unlikely(*aead))
 524		return -EEXIST;
 525
 526	/* Allocate a new AEAD */
 527	tmp = kzalloc(sizeof(*tmp), GFP_ATOMIC);
 528	if (unlikely(!tmp))
 529		return -ENOMEM;
 530
 531	/* The key consists of two parts: [AES-KEY][SALT] */
 532	keylen = ukey->keylen - TIPC_AES_GCM_SALT_SIZE;
 533
 534	/* Allocate per-cpu TFM entry pointer */
 535	tmp->tfm_entry = alloc_percpu(struct tipc_tfm *);
 536	if (!tmp->tfm_entry) {
 537		kfree_sensitive(tmp);
 538		return -ENOMEM;
 539	}
 540
 541	/* Make a list of TFMs with the user key data */
 542	do {
 543		tfm = crypto_alloc_aead(ukey->alg_name, 0, 0);
 544		if (IS_ERR(tfm)) {
 545			err = PTR_ERR(tfm);
 546			break;
 547		}
 548
 549		if (unlikely(!tfm_cnt &&
 550			     crypto_aead_ivsize(tfm) != TIPC_AES_GCM_IV_SIZE)) {
 551			crypto_free_aead(tfm);
 552			err = -ENOTSUPP;
 553			break;
 554		}
 555
 556		err = crypto_aead_setauthsize(tfm, TIPC_AES_GCM_TAG_SIZE);
 557		err |= crypto_aead_setkey(tfm, ukey->key, keylen);
 558		if (unlikely(err)) {
 559			crypto_free_aead(tfm);
 560			break;
 561		}
 562
 563		tfm_entry = kmalloc(sizeof(*tfm_entry), GFP_KERNEL);
 564		if (unlikely(!tfm_entry)) {
 565			crypto_free_aead(tfm);
 566			err = -ENOMEM;
 567			break;
 568		}
 569		INIT_LIST_HEAD(&tfm_entry->list);
 570		tfm_entry->tfm = tfm;
 571
 572		/* First entry? */
 573		if (!tfm_cnt) {
 574			head = tfm_entry;
 575			for_each_possible_cpu(cpu) {
 576				*per_cpu_ptr(tmp->tfm_entry, cpu) = head;
 577			}
 578		} else {
 579			list_add_tail(&tfm_entry->list, &head->list);
 580		}
 581
 582	} while (++tfm_cnt < sysctl_tipc_max_tfms);
 583
 584	/* Not any TFM is allocated? */
 585	if (!tfm_cnt) {
 586		free_percpu(tmp->tfm_entry);
 587		kfree_sensitive(tmp);
 588		return err;
 589	}
 590
 591	/* Form a hex string of some last bytes as the key's hint */
 592	bin2hex(tmp->hint, ukey->key + keylen - TIPC_AEAD_HINT_LEN,
 593		TIPC_AEAD_HINT_LEN);
 594
 595	/* Initialize the other data */
 596	tmp->mode = mode;
 597	tmp->cloned = NULL;
 598	tmp->authsize = TIPC_AES_GCM_TAG_SIZE;
 599	tmp->key = kmemdup(ukey, tipc_aead_key_size(ukey), GFP_KERNEL);
 600	memcpy(&tmp->salt, ukey->key + keylen, TIPC_AES_GCM_SALT_SIZE);
 601	atomic_set(&tmp->users, 0);
 602	atomic64_set(&tmp->seqno, 0);
 603	refcount_set(&tmp->refcnt, 1);
 604
 605	*aead = tmp;
 606	return 0;
 607}
 608
 609/**
 610 * tipc_aead_clone - Clone a TIPC AEAD key
 611 * @dst: dest key for the cloning
 612 * @src: source key to clone from
 613 *
 614 * Make a "copy" of the source AEAD key data to the dest, the TFMs list is
 615 * common for the keys.
 616 * A reference to the source is hold in the "cloned" pointer for the later
 617 * freeing purposes.
 618 *
 619 * Note: this must be done in cluster-key mode only!
 620 * Return: 0 in case of success, otherwise < 0
 621 */
 622static int tipc_aead_clone(struct tipc_aead **dst, struct tipc_aead *src)
 623{
 624	struct tipc_aead *aead;
 625	int cpu;
 626
 627	if (!src)
 628		return -ENOKEY;
 629
 630	if (src->mode != CLUSTER_KEY)
 631		return -EINVAL;
 632
 633	if (unlikely(*dst))
 634		return -EEXIST;
 635
 636	aead = kzalloc(sizeof(*aead), GFP_ATOMIC);
 637	if (unlikely(!aead))
 638		return -ENOMEM;
 639
 640	aead->tfm_entry = alloc_percpu_gfp(struct tipc_tfm *, GFP_ATOMIC);
 641	if (unlikely(!aead->tfm_entry)) {
 642		kfree_sensitive(aead);
 643		return -ENOMEM;
 644	}
 645
 646	for_each_possible_cpu(cpu) {
 647		*per_cpu_ptr(aead->tfm_entry, cpu) =
 648				*per_cpu_ptr(src->tfm_entry, cpu);
 649	}
 650
 651	memcpy(aead->hint, src->hint, sizeof(src->hint));
 652	aead->mode = src->mode;
 653	aead->salt = src->salt;
 654	aead->authsize = src->authsize;
 655	atomic_set(&aead->users, 0);
 656	atomic64_set(&aead->seqno, 0);
 657	refcount_set(&aead->refcnt, 1);
 658
 659	WARN_ON(!refcount_inc_not_zero(&src->refcnt));
 660	aead->cloned = src;
 661
 662	*dst = aead;
 663	return 0;
 664}
 665
 666/**
 667 * tipc_aead_mem_alloc - Allocate memory for AEAD request operations
 668 * @tfm: cipher handle to be registered with the request
 669 * @crypto_ctx_size: size of crypto context for callback
 670 * @iv: returned pointer to IV data
 671 * @req: returned pointer to AEAD request data
 672 * @sg: returned pointer to SG lists
 673 * @nsg: number of SG lists to be allocated
 674 *
 675 * Allocate memory to store the crypto context data, AEAD request, IV and SG
 676 * lists, the memory layout is as follows:
 677 * crypto_ctx || iv || aead_req || sg[]
 678 *
 679 * Return: the pointer to the memory areas in case of success, otherwise NULL
 680 */
 681static void *tipc_aead_mem_alloc(struct crypto_aead *tfm,
 682				 unsigned int crypto_ctx_size,
 683				 u8 **iv, struct aead_request **req,
 684				 struct scatterlist **sg, int nsg)
 685{
 686	unsigned int iv_size, req_size;
 687	unsigned int len;
 688	u8 *mem;
 689
 690	iv_size = crypto_aead_ivsize(tfm);
 691	req_size = sizeof(**req) + crypto_aead_reqsize(tfm);
 692
 693	len = crypto_ctx_size;
 694	len += iv_size;
 695	len += crypto_aead_alignmask(tfm) & ~(crypto_tfm_ctx_alignment() - 1);
 696	len = ALIGN(len, crypto_tfm_ctx_alignment());
 697	len += req_size;
 698	len = ALIGN(len, __alignof__(struct scatterlist));
 699	len += nsg * sizeof(**sg);
 700
 701	mem = kmalloc(len, GFP_ATOMIC);
 702	if (!mem)
 703		return NULL;
 704
 705	*iv = (u8 *)PTR_ALIGN(mem + crypto_ctx_size,
 706			      crypto_aead_alignmask(tfm) + 1);
 707	*req = (struct aead_request *)PTR_ALIGN(*iv + iv_size,
 708						crypto_tfm_ctx_alignment());
 709	*sg = (struct scatterlist *)PTR_ALIGN((u8 *)*req + req_size,
 710					      __alignof__(struct scatterlist));
 711
 712	return (void *)mem;
 713}
 714
 715/**
 716 * tipc_aead_encrypt - Encrypt a message
 717 * @aead: TIPC AEAD key for the message encryption
 718 * @skb: the input/output skb
 719 * @b: TIPC bearer where the message will be delivered after the encryption
 720 * @dst: the destination media address
 721 * @__dnode: TIPC dest node if "known"
 722 *
 723 * Return:
 724 * * 0                   : if the encryption has completed
 725 * * -EINPROGRESS/-EBUSY : if a callback will be performed
 726 * * < 0                 : the encryption has failed
 727 */
 728static int tipc_aead_encrypt(struct tipc_aead *aead, struct sk_buff *skb,
 729			     struct tipc_bearer *b,
 730			     struct tipc_media_addr *dst,
 731			     struct tipc_node *__dnode)
 732{
 733	struct crypto_aead *tfm = tipc_aead_tfm_next(aead);
 734	struct tipc_crypto_tx_ctx *tx_ctx;
 735	struct aead_request *req;
 736	struct sk_buff *trailer;
 737	struct scatterlist *sg;
 738	struct tipc_ehdr *ehdr;
 739	int ehsz, len, tailen, nsg, rc;
 740	void *ctx;
 741	u32 salt;
 742	u8 *iv;
 743
 744	/* Make sure message len at least 4-byte aligned */
 745	len = ALIGN(skb->len, 4);
 746	tailen = len - skb->len + aead->authsize;
 747
 748	/* Expand skb tail for authentication tag:
 749	 * As for simplicity, we'd have made sure skb having enough tailroom
 750	 * for authentication tag @skb allocation. Even when skb is nonlinear
 751	 * but there is no frag_list, it should be still fine!
 752	 * Otherwise, we must cow it to be a writable buffer with the tailroom.
 753	 */
 
 754	SKB_LINEAR_ASSERT(skb);
 755	if (tailen > skb_tailroom(skb)) {
 756		pr_debug("TX(): skb tailroom is not enough: %d, requires: %d\n",
 757			 skb_tailroom(skb), tailen);
 758	}
 
 759
 760	if (unlikely(!skb_cloned(skb) && tailen <= skb_tailroom(skb))) {
 761		nsg = 1;
 762		trailer = skb;
 763	} else {
 764		/* TODO: We could avoid skb_cow_data() if skb has no frag_list
 765		 * e.g. by skb_fill_page_desc() to add another page to the skb
 766		 * with the wanted tailen... However, page skbs look not often,
 767		 * so take it easy now!
 768		 * Cloned skbs e.g. from link_xmit() seems no choice though :(
 769		 */
 770		nsg = skb_cow_data(skb, tailen, &trailer);
 771		if (unlikely(nsg < 0)) {
 772			pr_err("TX: skb_cow_data() returned %d\n", nsg);
 773			return nsg;
 774		}
 775	}
 776
 777	pskb_put(skb, trailer, tailen);
 778
 779	/* Allocate memory for the AEAD operation */
 780	ctx = tipc_aead_mem_alloc(tfm, sizeof(*tx_ctx), &iv, &req, &sg, nsg);
 781	if (unlikely(!ctx))
 782		return -ENOMEM;
 783	TIPC_SKB_CB(skb)->crypto_ctx = ctx;
 784
 785	/* Map skb to the sg lists */
 786	sg_init_table(sg, nsg);
 787	rc = skb_to_sgvec(skb, sg, 0, skb->len);
 788	if (unlikely(rc < 0)) {
 789		pr_err("TX: skb_to_sgvec() returned %d, nsg %d!\n", rc, nsg);
 790		goto exit;
 791	}
 792
 793	/* Prepare IV: [SALT (4 octets)][SEQNO (8 octets)]
 794	 * In case we're in cluster-key mode, SALT is varied by xor-ing with
 795	 * the source address (or w0 of id), otherwise with the dest address
 796	 * if dest is known.
 797	 */
 798	ehdr = (struct tipc_ehdr *)skb->data;
 799	salt = aead->salt;
 800	if (aead->mode == CLUSTER_KEY)
 801		salt ^= __be32_to_cpu(ehdr->addr);
 802	else if (__dnode)
 803		salt ^= tipc_node_get_addr(__dnode);
 804	memcpy(iv, &salt, 4);
 805	memcpy(iv + 4, (u8 *)&ehdr->seqno, 8);
 806
 807	/* Prepare request */
 808	ehsz = tipc_ehdr_size(ehdr);
 809	aead_request_set_tfm(req, tfm);
 810	aead_request_set_ad(req, ehsz);
 811	aead_request_set_crypt(req, sg, sg, len - ehsz, iv);
 812
 813	/* Set callback function & data */
 814	aead_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
 815				  tipc_aead_encrypt_done, skb);
 816	tx_ctx = (struct tipc_crypto_tx_ctx *)ctx;
 817	tx_ctx->aead = aead;
 818	tx_ctx->bearer = b;
 819	memcpy(&tx_ctx->dst, dst, sizeof(*dst));
 820
 821	/* Hold bearer */
 822	if (unlikely(!tipc_bearer_hold(b))) {
 823		rc = -ENODEV;
 824		goto exit;
 825	}
 826
 827	/* Now, do encrypt */
 828	rc = crypto_aead_encrypt(req);
 829	if (rc == -EINPROGRESS || rc == -EBUSY)
 830		return rc;
 831
 832	tipc_bearer_put(b);
 833
 834exit:
 835	kfree(ctx);
 836	TIPC_SKB_CB(skb)->crypto_ctx = NULL;
 837	return rc;
 838}
 839
 840static void tipc_aead_encrypt_done(struct crypto_async_request *base, int err)
 841{
 842	struct sk_buff *skb = base->data;
 843	struct tipc_crypto_tx_ctx *tx_ctx = TIPC_SKB_CB(skb)->crypto_ctx;
 844	struct tipc_bearer *b = tx_ctx->bearer;
 845	struct tipc_aead *aead = tx_ctx->aead;
 846	struct tipc_crypto *tx = aead->crypto;
 847	struct net *net = tx->net;
 848
 849	switch (err) {
 850	case 0:
 851		this_cpu_inc(tx->stats->stat[STAT_ASYNC_OK]);
 852		rcu_read_lock();
 853		if (likely(test_bit(0, &b->up)))
 854			b->media->send_msg(net, skb, b, &tx_ctx->dst);
 855		else
 856			kfree_skb(skb);
 857		rcu_read_unlock();
 858		break;
 859	case -EINPROGRESS:
 860		return;
 861	default:
 862		this_cpu_inc(tx->stats->stat[STAT_ASYNC_NOK]);
 863		kfree_skb(skb);
 864		break;
 865	}
 866
 867	kfree(tx_ctx);
 868	tipc_bearer_put(b);
 869	tipc_aead_put(aead);
 870}
 871
 872/**
 873 * tipc_aead_decrypt - Decrypt an encrypted message
 874 * @net: struct net
 875 * @aead: TIPC AEAD for the message decryption
 876 * @skb: the input/output skb
 877 * @b: TIPC bearer where the message has been received
 878 *
 879 * Return:
 880 * * 0                   : if the decryption has completed
 881 * * -EINPROGRESS/-EBUSY : if a callback will be performed
 882 * * < 0                 : the decryption has failed
 883 */
 884static int tipc_aead_decrypt(struct net *net, struct tipc_aead *aead,
 885			     struct sk_buff *skb, struct tipc_bearer *b)
 886{
 887	struct tipc_crypto_rx_ctx *rx_ctx;
 888	struct aead_request *req;
 889	struct crypto_aead *tfm;
 890	struct sk_buff *unused;
 891	struct scatterlist *sg;
 892	struct tipc_ehdr *ehdr;
 893	int ehsz, nsg, rc;
 894	void *ctx;
 895	u32 salt;
 896	u8 *iv;
 897
 898	if (unlikely(!aead))
 899		return -ENOKEY;
 900
 901	nsg = skb_cow_data(skb, 0, &unused);
 902	if (unlikely(nsg < 0)) {
 903		pr_err("RX: skb_cow_data() returned %d\n", nsg);
 904		return nsg;
 
 
 
 
 
 
 905	}
 906
 907	/* Allocate memory for the AEAD operation */
 908	tfm = tipc_aead_tfm_next(aead);
 909	ctx = tipc_aead_mem_alloc(tfm, sizeof(*rx_ctx), &iv, &req, &sg, nsg);
 910	if (unlikely(!ctx))
 911		return -ENOMEM;
 912	TIPC_SKB_CB(skb)->crypto_ctx = ctx;
 913
 914	/* Map skb to the sg lists */
 915	sg_init_table(sg, nsg);
 916	rc = skb_to_sgvec(skb, sg, 0, skb->len);
 917	if (unlikely(rc < 0)) {
 918		pr_err("RX: skb_to_sgvec() returned %d, nsg %d\n", rc, nsg);
 919		goto exit;
 920	}
 921
 922	/* Reconstruct IV: */
 923	ehdr = (struct tipc_ehdr *)skb->data;
 924	salt = aead->salt;
 925	if (aead->mode == CLUSTER_KEY)
 926		salt ^= __be32_to_cpu(ehdr->addr);
 927	else if (ehdr->destined)
 928		salt ^= tipc_own_addr(net);
 929	memcpy(iv, &salt, 4);
 930	memcpy(iv + 4, (u8 *)&ehdr->seqno, 8);
 931
 932	/* Prepare request */
 933	ehsz = tipc_ehdr_size(ehdr);
 934	aead_request_set_tfm(req, tfm);
 935	aead_request_set_ad(req, ehsz);
 936	aead_request_set_crypt(req, sg, sg, skb->len - ehsz, iv);
 937
 938	/* Set callback function & data */
 939	aead_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
 940				  tipc_aead_decrypt_done, skb);
 941	rx_ctx = (struct tipc_crypto_rx_ctx *)ctx;
 942	rx_ctx->aead = aead;
 943	rx_ctx->bearer = b;
 944
 945	/* Hold bearer */
 946	if (unlikely(!tipc_bearer_hold(b))) {
 947		rc = -ENODEV;
 948		goto exit;
 949	}
 950
 951	/* Now, do decrypt */
 952	rc = crypto_aead_decrypt(req);
 953	if (rc == -EINPROGRESS || rc == -EBUSY)
 954		return rc;
 955
 956	tipc_bearer_put(b);
 957
 958exit:
 959	kfree(ctx);
 960	TIPC_SKB_CB(skb)->crypto_ctx = NULL;
 961	return rc;
 962}
 963
 964static void tipc_aead_decrypt_done(struct crypto_async_request *base, int err)
 965{
 966	struct sk_buff *skb = base->data;
 967	struct tipc_crypto_rx_ctx *rx_ctx = TIPC_SKB_CB(skb)->crypto_ctx;
 968	struct tipc_bearer *b = rx_ctx->bearer;
 969	struct tipc_aead *aead = rx_ctx->aead;
 970	struct tipc_crypto_stats __percpu *stats = aead->crypto->stats;
 971	struct net *net = aead->crypto->net;
 972
 973	switch (err) {
 974	case 0:
 975		this_cpu_inc(stats->stat[STAT_ASYNC_OK]);
 976		break;
 977	case -EINPROGRESS:
 978		return;
 979	default:
 980		this_cpu_inc(stats->stat[STAT_ASYNC_NOK]);
 981		break;
 982	}
 983
 984	kfree(rx_ctx);
 985	tipc_crypto_rcv_complete(net, aead, b, &skb, err);
 986	if (likely(skb)) {
 987		if (likely(test_bit(0, &b->up)))
 988			tipc_rcv(net, skb, b);
 989		else
 990			kfree_skb(skb);
 991	}
 992
 993	tipc_bearer_put(b);
 994}
 995
 996static inline int tipc_ehdr_size(struct tipc_ehdr *ehdr)
 997{
 998	return (ehdr->user != LINK_CONFIG) ? EHDR_SIZE : EHDR_CFG_SIZE;
 999}
1000
1001/**
1002 * tipc_ehdr_validate - Validate an encryption message
1003 * @skb: the message buffer
1004 *
1005 * Return: "true" if this is a valid encryption message, otherwise "false"
1006 */
1007bool tipc_ehdr_validate(struct sk_buff *skb)
1008{
1009	struct tipc_ehdr *ehdr;
1010	int ehsz;
1011
1012	if (unlikely(!pskb_may_pull(skb, EHDR_MIN_SIZE)))
1013		return false;
1014
1015	ehdr = (struct tipc_ehdr *)skb->data;
1016	if (unlikely(ehdr->version != TIPC_EVERSION))
1017		return false;
1018	ehsz = tipc_ehdr_size(ehdr);
1019	if (unlikely(!pskb_may_pull(skb, ehsz)))
1020		return false;
1021	if (unlikely(skb->len <= ehsz + TIPC_AES_GCM_TAG_SIZE))
1022		return false;
 
 
1023
1024	return true;
1025}
1026
1027/**
1028 * tipc_ehdr_build - Build TIPC encryption message header
1029 * @net: struct net
1030 * @aead: TX AEAD key to be used for the message encryption
1031 * @tx_key: key id used for the message encryption
1032 * @skb: input/output message skb
1033 * @__rx: RX crypto handle if dest is "known"
1034 *
1035 * Return: the header size if the building is successful, otherwise < 0
1036 */
1037static int tipc_ehdr_build(struct net *net, struct tipc_aead *aead,
1038			   u8 tx_key, struct sk_buff *skb,
1039			   struct tipc_crypto *__rx)
1040{
1041	struct tipc_msg *hdr = buf_msg(skb);
1042	struct tipc_ehdr *ehdr;
1043	u32 user = msg_user(hdr);
1044	u64 seqno;
1045	int ehsz;
1046
1047	/* Make room for encryption header */
1048	ehsz = (user != LINK_CONFIG) ? EHDR_SIZE : EHDR_CFG_SIZE;
1049	WARN_ON(skb_headroom(skb) < ehsz);
1050	ehdr = (struct tipc_ehdr *)skb_push(skb, ehsz);
1051
1052	/* Obtain a seqno first:
1053	 * Use the key seqno (= cluster wise) if dest is unknown or we're in
1054	 * cluster key mode, otherwise it's better for a per-peer seqno!
1055	 */
1056	if (!__rx || aead->mode == CLUSTER_KEY)
1057		seqno = atomic64_inc_return(&aead->seqno);
1058	else
1059		seqno = atomic64_inc_return(&__rx->sndnxt);
1060
1061	/* Revoke the key if seqno is wrapped around */
1062	if (unlikely(!seqno))
1063		return tipc_crypto_key_revoke(net, tx_key);
1064
1065	/* Word 1-2 */
1066	ehdr->seqno = cpu_to_be64(seqno);
1067
1068	/* Words 0, 3- */
1069	ehdr->version = TIPC_EVERSION;
1070	ehdr->user = 0;
1071	ehdr->keepalive = 0;
1072	ehdr->tx_key = tx_key;
1073	ehdr->destined = (__rx) ? 1 : 0;
1074	ehdr->rx_key_active = (__rx) ? __rx->key.active : 0;
1075	ehdr->rx_nokey = (__rx) ? __rx->nokey : 0;
1076	ehdr->master_key = aead->crypto->key_master;
1077	ehdr->reserved_1 = 0;
1078	ehdr->reserved_2 = 0;
1079
1080	switch (user) {
1081	case LINK_CONFIG:
1082		ehdr->user = LINK_CONFIG;
1083		memcpy(ehdr->id, tipc_own_id(net), NODE_ID_LEN);
1084		break;
1085	default:
1086		if (user == LINK_PROTOCOL && msg_type(hdr) == STATE_MSG) {
1087			ehdr->user = LINK_PROTOCOL;
1088			ehdr->keepalive = msg_is_keepalive(hdr);
1089		}
1090		ehdr->addr = hdr->hdr[3];
1091		break;
1092	}
1093
1094	return ehsz;
1095}
1096
1097static inline void tipc_crypto_key_set_state(struct tipc_crypto *c,
1098					     u8 new_passive,
1099					     u8 new_active,
1100					     u8 new_pending)
1101{
 
1102	struct tipc_key old = c->key;
1103	char buf[32];
 
1104
1105	c->key.keys = ((new_passive & KEY_MASK) << (KEY_BITS * 2)) |
1106		      ((new_active  & KEY_MASK) << (KEY_BITS)) |
1107		      ((new_pending & KEY_MASK));
1108
1109	pr_debug("%s: key changing %s ::%pS\n", c->name,
1110		 tipc_key_change_dump(old, c->key, buf),
1111		 __builtin_return_address(0));
 
 
 
 
 
1112}
1113
1114/**
1115 * tipc_crypto_key_init - Initiate a new user / AEAD key
1116 * @c: TIPC crypto to which new key is attached
1117 * @ukey: the user key
1118 * @mode: the key mode (CLUSTER_KEY or PER_NODE_KEY)
1119 * @master_key: specify this is a cluster master key
1120 *
1121 * A new TIPC AEAD key will be allocated and initiated with the specified user
1122 * key, then attached to the TIPC crypto.
1123 *
1124 * Return: new key id in case of success, otherwise: < 0
1125 */
1126int tipc_crypto_key_init(struct tipc_crypto *c, struct tipc_aead_key *ukey,
1127			 u8 mode, bool master_key)
1128{
1129	struct tipc_aead *aead = NULL;
1130	int rc = 0;
1131
1132	/* Initiate with the new user key */
1133	rc = tipc_aead_init(&aead, ukey, mode);
1134
1135	/* Attach it to the crypto */
1136	if (likely(!rc)) {
1137		rc = tipc_crypto_key_attach(c, aead, 0, master_key);
1138		if (rc < 0)
1139			tipc_aead_free(&aead->rcu);
1140	}
1141
 
 
 
 
 
 
1142	return rc;
1143}
1144
1145/**
1146 * tipc_crypto_key_attach - Attach a new AEAD key to TIPC crypto
1147 * @c: TIPC crypto to which the new AEAD key is attached
1148 * @aead: the new AEAD key pointer
1149 * @pos: desired slot in the crypto key array, = 0 if any!
1150 * @master_key: specify this is a cluster master key
1151 *
1152 * Return: new key id in case of success, otherwise: -EBUSY
1153 */
1154static int tipc_crypto_key_attach(struct tipc_crypto *c,
1155				  struct tipc_aead *aead, u8 pos,
1156				  bool master_key)
1157{
 
1158	struct tipc_key key;
1159	int rc = -EBUSY;
1160	u8 new_key;
1161
1162	spin_lock_bh(&c->lock);
1163	key = c->key;
1164	if (master_key) {
1165		new_key = KEY_MASTER;
1166		goto attach;
1167	}
1168	if (key.active && key.passive)
1169		goto exit;
 
 
1170	if (key.pending) {
 
 
1171		if (tipc_aead_users(c->aead[key.pending]) > 0)
1172			goto exit;
1173		/* if (pos): ok with replacing, will be aligned when needed */
1174		/* Replace it */
1175		new_key = key.pending;
 
 
1176	} else {
1177		if (pos) {
1178			if (key.active && pos != key_next(key.active)) {
1179				key.passive = pos;
1180				new_key = pos;
 
1181				goto attach;
1182			} else if (!key.active && !key.passive) {
1183				key.pending = pos;
1184				new_key = pos;
 
1185				goto attach;
1186			}
1187		}
1188		key.pending = key_next(key.active ?: key.passive);
1189		new_key = key.pending;
 
1190	}
1191
1192attach:
1193	aead->crypto = c;
1194	aead->gen = (is_tx(c)) ? ++c->key_gen : c->key_gen;
1195	tipc_aead_rcu_replace(c->aead[new_key], aead, &c->lock);
1196	if (likely(c->key.keys != key.keys))
1197		tipc_crypto_key_set_state(c, key.passive, key.active,
1198					  key.pending);
1199	c->working = 1;
1200	c->nokey = 0;
1201	c->key_master |= master_key;
1202	rc = new_key;
1203
1204exit:
1205	spin_unlock_bh(&c->lock);
1206	return rc;
1207}
1208
1209void tipc_crypto_key_flush(struct tipc_crypto *c)
1210{
1211	struct tipc_crypto *tx, *rx;
1212	int k;
1213
1214	spin_lock_bh(&c->lock);
1215	if (is_rx(c)) {
1216		/* Try to cancel pending work */
1217		rx = c;
1218		tx = tipc_net(rx->net)->crypto_tx;
1219		if (cancel_delayed_work(&rx->work)) {
1220			kfree(rx->skey);
1221			rx->skey = NULL;
1222			atomic_xchg(&rx->key_distr, 0);
1223			tipc_node_put(rx->node);
1224		}
1225		/* RX stopping => decrease TX key users if any */
1226		k = atomic_xchg(&rx->peer_rx_active, 0);
1227		if (k) {
1228			tipc_aead_users_dec(tx->aead[k], 0);
1229			/* Mark the point TX key users changed */
1230			tx->timer1 = jiffies;
1231		}
1232	}
1233
1234	c->flags = 0;
1235	tipc_crypto_key_set_state(c, 0, 0, 0);
1236	for (k = KEY_MIN; k <= KEY_MAX; k++)
1237		tipc_crypto_key_detach(c->aead[k], &c->lock);
 
1238	atomic64_set(&c->sndnxt, 0);
1239	spin_unlock_bh(&c->lock);
1240}
1241
1242/**
1243 * tipc_crypto_key_try_align - Align RX keys if possible
1244 * @rx: RX crypto handle
1245 * @new_pending: new pending slot if aligned (= TX key from peer)
1246 *
1247 * Peer has used an unknown key slot, this only happens when peer has left and
1248 * rejoned, or we are newcomer.
1249 * That means, there must be no active key but a pending key at unaligned slot.
1250 * If so, we try to move the pending key to the new slot.
1251 * Note: A potential passive key can exist, it will be shifted correspondingly!
1252 *
1253 * Return: "true" if key is successfully aligned, otherwise "false"
1254 */
1255static bool tipc_crypto_key_try_align(struct tipc_crypto *rx, u8 new_pending)
1256{
1257	struct tipc_aead *tmp1, *tmp2 = NULL;
1258	struct tipc_key key;
1259	bool aligned = false;
1260	u8 new_passive = 0;
1261	int x;
1262
1263	spin_lock(&rx->lock);
1264	key = rx->key;
1265	if (key.pending == new_pending) {
1266		aligned = true;
1267		goto exit;
1268	}
1269	if (key.active)
1270		goto exit;
1271	if (!key.pending)
1272		goto exit;
1273	if (tipc_aead_users(rx->aead[key.pending]) > 0)
1274		goto exit;
1275
1276	/* Try to "isolate" this pending key first */
1277	tmp1 = tipc_aead_rcu_ptr(rx->aead[key.pending], &rx->lock);
1278	if (!refcount_dec_if_one(&tmp1->refcnt))
1279		goto exit;
1280	rcu_assign_pointer(rx->aead[key.pending], NULL);
1281
1282	/* Move passive key if any */
1283	if (key.passive) {
1284		tmp2 = rcu_replace_pointer(rx->aead[key.passive], tmp2, lockdep_is_held(&rx->lock));
1285		x = (key.passive - key.pending + new_pending) % KEY_MAX;
1286		new_passive = (x <= 0) ? x + KEY_MAX : x;
1287	}
1288
1289	/* Re-allocate the key(s) */
1290	tipc_crypto_key_set_state(rx, new_passive, 0, new_pending);
1291	rcu_assign_pointer(rx->aead[new_pending], tmp1);
1292	if (new_passive)
1293		rcu_assign_pointer(rx->aead[new_passive], tmp2);
1294	refcount_set(&tmp1->refcnt, 1);
1295	aligned = true;
1296	pr_info_ratelimited("%s: key[%d] -> key[%d]\n", rx->name, key.pending,
1297			    new_pending);
1298
1299exit:
1300	spin_unlock(&rx->lock);
1301	return aligned;
1302}
1303
1304/**
1305 * tipc_crypto_key_pick_tx - Pick one TX key for message decryption
1306 * @tx: TX crypto handle
1307 * @rx: RX crypto handle (can be NULL)
1308 * @skb: the message skb which will be decrypted later
1309 * @tx_key: peer TX key id
1310 *
1311 * This function looks up the existing TX keys and pick one which is suitable
1312 * for the message decryption, that must be a cluster key and not used before
1313 * on the same message (i.e. recursive).
1314 *
1315 * Return: the TX AEAD key handle in case of success, otherwise NULL
1316 */
1317static struct tipc_aead *tipc_crypto_key_pick_tx(struct tipc_crypto *tx,
1318						 struct tipc_crypto *rx,
1319						 struct sk_buff *skb,
1320						 u8 tx_key)
1321{
1322	struct tipc_skb_cb *skb_cb = TIPC_SKB_CB(skb);
1323	struct tipc_aead *aead = NULL;
1324	struct tipc_key key = tx->key;
1325	u8 k, i = 0;
1326
1327	/* Initialize data if not yet */
1328	if (!skb_cb->tx_clone_deferred) {
1329		skb_cb->tx_clone_deferred = 1;
1330		memset(&skb_cb->tx_clone_ctx, 0, sizeof(skb_cb->tx_clone_ctx));
1331	}
1332
1333	skb_cb->tx_clone_ctx.rx = rx;
1334	if (++skb_cb->tx_clone_ctx.recurs > 2)
1335		return NULL;
1336
1337	/* Pick one TX key */
1338	spin_lock(&tx->lock);
1339	if (tx_key == KEY_MASTER) {
1340		aead = tipc_aead_rcu_ptr(tx->aead[KEY_MASTER], &tx->lock);
1341		goto done;
1342	}
1343	do {
1344		k = (i == 0) ? key.pending :
1345			((i == 1) ? key.active : key.passive);
1346		if (!k)
1347			continue;
1348		aead = tipc_aead_rcu_ptr(tx->aead[k], &tx->lock);
1349		if (!aead)
1350			continue;
1351		if (aead->mode != CLUSTER_KEY ||
1352		    aead == skb_cb->tx_clone_ctx.last) {
1353			aead = NULL;
1354			continue;
1355		}
1356		/* Ok, found one cluster key */
1357		skb_cb->tx_clone_ctx.last = aead;
1358		WARN_ON(skb->next);
1359		skb->next = skb_clone(skb, GFP_ATOMIC);
1360		if (unlikely(!skb->next))
1361			pr_warn("Failed to clone skb for next round if any\n");
 
1362		break;
1363	} while (++i < 3);
1364
1365done:
1366	if (likely(aead))
1367		WARN_ON(!refcount_inc_not_zero(&aead->refcnt));
1368	spin_unlock(&tx->lock);
1369
1370	return aead;
1371}
1372
1373/**
1374 * tipc_crypto_key_synch: Synch own key data according to peer key status
1375 * @rx: RX crypto handle
1376 * @skb: TIPCv2 message buffer (incl. the ehdr from peer)
 
1377 *
1378 * This function updates the peer node related data as the peer RX active key
1379 * has changed, so the number of TX keys' users on this node are increased and
1380 * decreased correspondingly.
1381 *
1382 * It also considers if peer has no key, then we need to make own master key
1383 * (if any) taking over i.e. starting grace period and also trigger key
1384 * distributing process.
1385 *
1386 * The "per-peer" sndnxt is also reset when the peer key has switched.
1387 */
1388static void tipc_crypto_key_synch(struct tipc_crypto *rx, struct sk_buff *skb)
 
1389{
1390	struct tipc_ehdr *ehdr = (struct tipc_ehdr *)skb_network_header(skb);
1391	struct tipc_crypto *tx = tipc_net(rx->net)->crypto_tx;
1392	struct tipc_msg *hdr = buf_msg(skb);
1393	u32 self = tipc_own_addr(rx->net);
1394	u8 cur, new;
1395	unsigned long delay;
1396
1397	/* Update RX 'key_master' flag according to peer, also mark "legacy" if
1398	 * a peer has no master key.
1399	 */
1400	rx->key_master = ehdr->master_key;
1401	if (!rx->key_master)
1402		tx->legacy_user = 1;
1403
1404	/* For later cases, apply only if message is destined to this node */
1405	if (!ehdr->destined || msg_short(hdr) || msg_destnode(hdr) != self)
1406		return;
1407
1408	/* Case 1: Peer has no keys, let's make master key take over */
1409	if (ehdr->rx_nokey) {
1410		/* Set or extend grace period */
1411		tx->timer2 = jiffies;
1412		/* Schedule key distributing for the peer if not yet */
1413		if (tx->key.keys &&
1414		    !atomic_cmpxchg(&rx->key_distr, 0, KEY_DISTR_SCHED)) {
1415			get_random_bytes(&delay, 2);
1416			delay %= 5;
1417			delay = msecs_to_jiffies(500 * ++delay);
1418			if (queue_delayed_work(tx->wq, &rx->work, delay))
1419				tipc_node_get(rx->node);
1420		}
1421	} else {
1422		/* Cancel a pending key distributing if any */
1423		atomic_xchg(&rx->key_distr, 0);
1424	}
1425
1426	/* Case 2: Peer RX active key has changed, let's update own TX users */
1427	cur = atomic_read(&rx->peer_rx_active);
1428	new = ehdr->rx_key_active;
1429	if (tx->key.keys &&
1430	    cur != new &&
1431	    atomic_cmpxchg(&rx->peer_rx_active, cur, new) == cur) {
1432		if (new)
1433			tipc_aead_users_inc(tx->aead[new], INT_MAX);
1434		if (cur)
1435			tipc_aead_users_dec(tx->aead[cur], 0);
1436
1437		atomic64_set(&rx->sndnxt, 0);
1438		/* Mark the point TX key users changed */
1439		tx->timer1 = jiffies;
1440
1441		pr_debug("%s: key users changed %d-- %d++, peer %s\n",
1442			 tx->name, cur, new, rx->name);
 
 
 
1443	}
1444}
1445
1446static int tipc_crypto_key_revoke(struct net *net, u8 tx_key)
1447{
1448	struct tipc_crypto *tx = tipc_net(net)->crypto_tx;
1449	struct tipc_key key;
1450
1451	spin_lock(&tx->lock);
1452	key = tx->key;
1453	WARN_ON(!key.active || tx_key != key.active);
1454
1455	/* Free the active key */
1456	tipc_crypto_key_set_state(tx, key.passive, 0, key.pending);
1457	tipc_crypto_key_detach(tx->aead[key.active], &tx->lock);
1458	spin_unlock(&tx->lock);
1459
1460	pr_warn("%s: key is revoked\n", tx->name);
1461	return -EKEYREVOKED;
1462}
1463
1464int tipc_crypto_start(struct tipc_crypto **crypto, struct net *net,
1465		      struct tipc_node *node)
1466{
1467	struct tipc_crypto *c;
1468
1469	if (*crypto)
1470		return -EEXIST;
1471
1472	/* Allocate crypto */
1473	c = kzalloc(sizeof(*c), GFP_ATOMIC);
1474	if (!c)
1475		return -ENOMEM;
1476
1477	/* Allocate workqueue on TX */
1478	if (!node) {
1479		c->wq = alloc_ordered_workqueue("tipc_crypto", 0);
1480		if (!c->wq) {
1481			kfree(c);
1482			return -ENOMEM;
1483		}
1484	}
1485
1486	/* Allocate statistic structure */
1487	c->stats = alloc_percpu_gfp(struct tipc_crypto_stats, GFP_ATOMIC);
1488	if (!c->stats) {
1489		if (c->wq)
1490			destroy_workqueue(c->wq);
1491		kfree_sensitive(c);
1492		return -ENOMEM;
1493	}
1494
1495	c->flags = 0;
1496	c->net = net;
1497	c->node = node;
1498	get_random_bytes(&c->key_gen, 2);
1499	tipc_crypto_key_set_state(c, 0, 0, 0);
1500	atomic_set(&c->key_distr, 0);
1501	atomic_set(&c->peer_rx_active, 0);
1502	atomic64_set(&c->sndnxt, 0);
1503	c->timer1 = jiffies;
1504	c->timer2 = jiffies;
1505	c->rekeying_intv = TIPC_REKEYING_INTV_DEF;
1506	spin_lock_init(&c->lock);
1507	scnprintf(c->name, 48, "%s(%s)", (is_rx(c)) ? "RX" : "TX",
1508		  (is_rx(c)) ? tipc_node_get_id_str(c->node) :
1509			       tipc_own_id_string(c->net));
1510
1511	if (is_rx(c))
1512		INIT_DELAYED_WORK(&c->work, tipc_crypto_work_rx);
1513	else
1514		INIT_DELAYED_WORK(&c->work, tipc_crypto_work_tx);
1515
1516	*crypto = c;
 
1517	return 0;
1518}
1519
1520void tipc_crypto_stop(struct tipc_crypto **crypto)
1521{
1522	struct tipc_crypto *c = *crypto;
 
1523	u8 k;
1524
1525	if (!c)
1526		return;
1527
1528	/* Flush any queued works & destroy wq */
1529	if (is_tx(c)) {
1530		c->rekeying_intv = 0;
1531		cancel_delayed_work_sync(&c->work);
1532		destroy_workqueue(c->wq);
 
 
 
 
 
 
 
1533	}
1534
1535	/* Release AEAD keys */
1536	rcu_read_lock();
1537	for (k = KEY_MIN; k <= KEY_MAX; k++)
1538		tipc_aead_put(rcu_dereference(c->aead[k]));
1539	rcu_read_unlock();
1540	pr_debug("%s: has been stopped\n", c->name);
 
 
 
 
1541
1542	/* Free this crypto statistics */
1543	free_percpu(c->stats);
1544
1545	*crypto = NULL;
1546	kfree_sensitive(c);
1547}
1548
1549void tipc_crypto_timeout(struct tipc_crypto *rx)
1550{
1551	struct tipc_net *tn = tipc_net(rx->net);
1552	struct tipc_crypto *tx = tn->crypto_tx;
1553	struct tipc_key key;
 
1554	int cmd;
1555
1556	/* TX pending: taking all users & stable -> active */
 
 
 
1557	spin_lock(&tx->lock);
1558	key = tx->key;
1559	if (key.active && tipc_aead_users(tx->aead[key.active]) > 0)
1560		goto s1;
1561	if (!key.pending || tipc_aead_users(tx->aead[key.pending]) <= 0)
1562		goto s1;
1563	if (time_before(jiffies, tx->timer1 + TIPC_TX_LASTING_TIME))
1564		goto s1;
1565
1566	tipc_crypto_key_set_state(tx, key.passive, key.pending, 0);
1567	if (key.active)
1568		tipc_crypto_key_detach(tx->aead[key.active], &tx->lock);
1569	this_cpu_inc(tx->stats->stat[STAT_SWITCHES]);
1570	pr_info("%s: key[%d] is activated\n", tx->name, key.pending);
 
1571
1572s1:
1573	spin_unlock(&tx->lock);
1574
1575	/* RX pending: having user -> active */
 
 
 
1576	spin_lock(&rx->lock);
1577	key = rx->key;
1578	if (!key.pending || tipc_aead_users(rx->aead[key.pending]) <= 0)
1579		goto s2;
1580
1581	if (key.active)
1582		key.passive = key.active;
1583	key.active = key.pending;
1584	rx->timer2 = jiffies;
1585	tipc_crypto_key_set_state(rx, key.passive, key.active, 0);
1586	this_cpu_inc(rx->stats->stat[STAT_SWITCHES]);
1587	pr_info("%s: key[%d] is activated\n", rx->name, key.pending);
 
1588	goto s5;
1589
1590s2:
1591	/* RX pending: not working -> remove */
1592	if (!key.pending || tipc_aead_users(rx->aead[key.pending]) > -10)
 
 
 
 
 
 
 
1593		goto s3;
1594
1595	tipc_crypto_key_set_state(rx, key.passive, key.active, 0);
1596	tipc_crypto_key_detach(rx->aead[key.pending], &rx->lock);
1597	pr_debug("%s: key[%d] is removed\n", rx->name, key.pending);
1598	goto s5;
1599
1600s3:
1601	/* RX active: timed out or no user -> pending */
 
 
 
 
 
1602	if (!key.active)
1603		goto s4;
1604	if (time_before(jiffies, rx->timer1 + TIPC_RX_ACTIVE_LIM) &&
1605	    tipc_aead_users(rx->aead[key.active]) > 0)
1606		goto s4;
1607
1608	if (key.pending)
1609		key.passive = key.active;
1610	else
1611		key.pending = key.active;
1612	rx->timer2 = jiffies;
1613	tipc_crypto_key_set_state(rx, key.passive, 0, key.pending);
1614	tipc_aead_users_set(rx->aead[key.pending], 0);
1615	pr_debug("%s: key[%d] is deactivated\n", rx->name, key.active);
1616	goto s5;
1617
1618s4:
1619	/* RX passive: outdated or not working -> free */
1620	if (!key.passive)
 
1621		goto s5;
1622	if (time_before(jiffies, rx->timer2 + TIPC_RX_PASSIVE_LIM) &&
1623	    tipc_aead_users(rx->aead[key.passive]) > -10)
1624		goto s5;
1625
1626	tipc_crypto_key_set_state(rx, 0, key.active, key.pending);
1627	tipc_crypto_key_detach(rx->aead[key.passive], &rx->lock);
1628	pr_debug("%s: key[%d] is freed\n", rx->name, key.passive);
 
1629
1630s5:
1631	spin_unlock(&rx->lock);
1632
1633	/* Relax it here, the flag will be set again if it really is, but only
1634	 * when we are not in grace period for safety!
1635	 */
1636	if (time_after(jiffies, tx->timer2 + TIPC_TX_GRACE_PERIOD))
1637		tx->legacy_user = 0;
1638
1639	/* Limit max_tfms & do debug commands if needed */
1640	if (likely(sysctl_tipc_max_tfms <= TIPC_MAX_TFMS_LIM))
1641		return;
1642
1643	cmd = sysctl_tipc_max_tfms;
1644	sysctl_tipc_max_tfms = TIPC_MAX_TFMS_DEF;
1645	tipc_crypto_do_cmd(rx->net, cmd);
1646}
1647
1648static inline void tipc_crypto_clone_msg(struct net *net, struct sk_buff *_skb,
1649					 struct tipc_bearer *b,
1650					 struct tipc_media_addr *dst,
1651					 struct tipc_node *__dnode, u8 type)
1652{
1653	struct sk_buff *skb;
1654
1655	skb = skb_clone(_skb, GFP_ATOMIC);
1656	if (skb) {
1657		TIPC_SKB_CB(skb)->xmit_type = type;
1658		tipc_crypto_xmit(net, &skb, b, dst, __dnode);
1659		if (skb)
1660			b->media->send_msg(net, skb, b, dst);
1661	}
1662}
1663
1664/**
1665 * tipc_crypto_xmit - Build & encrypt TIPC message for xmit
1666 * @net: struct net
1667 * @skb: input/output message skb pointer
1668 * @b: bearer used for xmit later
1669 * @dst: destination media address
1670 * @__dnode: destination node for reference if any
1671 *
1672 * First, build an encryption message header on the top of the message, then
1673 * encrypt the original TIPC message by using the pending, master or active
1674 * key with this preference order.
1675 * If the encryption is successful, the encrypted skb is returned directly or
1676 * via the callback.
1677 * Otherwise, the skb is freed!
1678 *
1679 * Return:
1680 * * 0                   : the encryption has succeeded (or no encryption)
1681 * * -EINPROGRESS/-EBUSY : the encryption is ongoing, a callback will be made
1682 * * -ENOKEK             : the encryption has failed due to no key
1683 * * -EKEYREVOKED        : the encryption has failed due to key revoked
1684 * * -ENOMEM             : the encryption has failed due to no memory
1685 * * < 0                 : the encryption has failed due to other reasons
1686 */
1687int tipc_crypto_xmit(struct net *net, struct sk_buff **skb,
1688		     struct tipc_bearer *b, struct tipc_media_addr *dst,
1689		     struct tipc_node *__dnode)
1690{
1691	struct tipc_crypto *__rx = tipc_node_crypto_rx(__dnode);
1692	struct tipc_crypto *tx = tipc_net(net)->crypto_tx;
1693	struct tipc_crypto_stats __percpu *stats = tx->stats;
1694	struct tipc_msg *hdr = buf_msg(*skb);
1695	struct tipc_key key = tx->key;
1696	struct tipc_aead *aead = NULL;
1697	u32 user = msg_user(hdr);
1698	u32 type = msg_type(hdr);
1699	int rc = -ENOKEY;
1700	u8 tx_key = 0;
1701
1702	/* No encryption? */
1703	if (!tx->working)
1704		return 0;
1705
1706	/* Pending key if peer has active on it or probing time */
 
 
 
 
1707	if (unlikely(key.pending)) {
1708		tx_key = key.pending;
1709		if (!tx->key_master && !key.active)
1710			goto encrypt;
1711		if (__rx && atomic_read(&__rx->peer_rx_active) == tx_key)
1712			goto encrypt;
1713		if (TIPC_SKB_CB(*skb)->xmit_type == SKB_PROBING) {
1714			pr_debug("%s: probing for key[%d]\n", tx->name,
1715				 key.pending);
1716			goto encrypt;
1717		}
1718		if (user == LINK_CONFIG || user == LINK_PROTOCOL)
1719			tipc_crypto_clone_msg(net, *skb, b, dst, __dnode,
1720					      SKB_PROBING);
1721	}
1722
1723	/* Master key if this is a *vital* message or in grace period */
1724	if (tx->key_master) {
1725		tx_key = KEY_MASTER;
1726		if (!key.active)
1727			goto encrypt;
1728		if (TIPC_SKB_CB(*skb)->xmit_type == SKB_GRACING) {
1729			pr_debug("%s: gracing for msg (%d %d)\n", tx->name,
1730				 user, type);
1731			goto encrypt;
1732		}
1733		if (user == LINK_CONFIG ||
1734		    (user == LINK_PROTOCOL && type == RESET_MSG) ||
1735		    (user == MSG_CRYPTO && type == KEY_DISTR_MSG) ||
1736		    time_before(jiffies, tx->timer2 + TIPC_TX_GRACE_PERIOD)) {
1737			if (__rx && __rx->key_master &&
1738			    !atomic_read(&__rx->peer_rx_active))
1739				goto encrypt;
1740			if (!__rx) {
1741				if (likely(!tx->legacy_user))
1742					goto encrypt;
1743				tipc_crypto_clone_msg(net, *skb, b, dst,
1744						      __dnode, SKB_GRACING);
1745			}
1746		}
1747	}
1748
1749	/* Else, use the active key if any */
1750	if (likely(key.active)) {
1751		tx_key = key.active;
1752		goto encrypt;
1753	}
1754
1755	goto exit;
1756
1757encrypt:
1758	aead = tipc_aead_get(tx->aead[tx_key]);
1759	if (unlikely(!aead))
1760		goto exit;
1761	rc = tipc_ehdr_build(net, aead, tx_key, *skb, __rx);
1762	if (likely(rc > 0))
1763		rc = tipc_aead_encrypt(aead, *skb, b, dst, __dnode);
1764
1765exit:
1766	switch (rc) {
1767	case 0:
1768		this_cpu_inc(stats->stat[STAT_OK]);
1769		break;
1770	case -EINPROGRESS:
1771	case -EBUSY:
1772		this_cpu_inc(stats->stat[STAT_ASYNC]);
1773		*skb = NULL;
1774		return rc;
1775	default:
1776		this_cpu_inc(stats->stat[STAT_NOK]);
1777		if (rc == -ENOKEY)
1778			this_cpu_inc(stats->stat[STAT_NOKEYS]);
1779		else if (rc == -EKEYREVOKED)
1780			this_cpu_inc(stats->stat[STAT_BADKEYS]);
1781		kfree_skb(*skb);
1782		*skb = NULL;
1783		break;
1784	}
1785
1786	tipc_aead_put(aead);
1787	return rc;
1788}
1789
1790/**
1791 * tipc_crypto_rcv - Decrypt an encrypted TIPC message from peer
1792 * @net: struct net
1793 * @rx: RX crypto handle
1794 * @skb: input/output message skb pointer
1795 * @b: bearer where the message has been received
1796 *
1797 * If the decryption is successful, the decrypted skb is returned directly or
1798 * as the callback, the encryption header and auth tag will be trimed out
1799 * before forwarding to tipc_rcv() via the tipc_crypto_rcv_complete().
1800 * Otherwise, the skb will be freed!
1801 * Note: RX key(s) can be re-aligned, or in case of no key suitable, TX
1802 * cluster key(s) can be taken for decryption (- recursive).
1803 *
1804 * Return:
1805 * * 0                   : the decryption has successfully completed
1806 * * -EINPROGRESS/-EBUSY : the decryption is ongoing, a callback will be made
1807 * * -ENOKEY             : the decryption has failed due to no key
1808 * * -EBADMSG            : the decryption has failed due to bad message
1809 * * -ENOMEM             : the decryption has failed due to no memory
1810 * * < 0                 : the decryption has failed due to other reasons
1811 */
1812int tipc_crypto_rcv(struct net *net, struct tipc_crypto *rx,
1813		    struct sk_buff **skb, struct tipc_bearer *b)
1814{
1815	struct tipc_crypto *tx = tipc_net(net)->crypto_tx;
1816	struct tipc_crypto_stats __percpu *stats;
1817	struct tipc_aead *aead = NULL;
1818	struct tipc_key key;
1819	int rc = -ENOKEY;
1820	u8 tx_key, n;
1821
1822	tx_key = ((struct tipc_ehdr *)(*skb)->data)->tx_key;
1823
1824	/* New peer?
1825	 * Let's try with TX key (i.e. cluster mode) & verify the skb first!
1826	 */
1827	if (unlikely(!rx || tx_key == KEY_MASTER))
1828		goto pick_tx;
1829
1830	/* Pick RX key according to TX key if any */
 
 
 
 
 
1831	key = rx->key;
1832	if (tx_key == key.active || tx_key == key.pending ||
1833	    tx_key == key.passive)
 
1834		goto decrypt;
 
 
 
 
 
1835
1836	/* Unknown key, let's try to align RX key(s) */
1837	if (tipc_crypto_key_try_align(rx, tx_key))
1838		goto decrypt;
1839
1840pick_tx:
1841	/* No key suitable? Try to pick one from TX... */
1842	aead = tipc_crypto_key_pick_tx(tx, rx, *skb, tx_key);
1843	if (aead)
1844		goto decrypt;
1845	goto exit;
1846
1847decrypt:
1848	rcu_read_lock();
1849	if (!aead)
1850		aead = tipc_aead_get(rx->aead[tx_key]);
1851	rc = tipc_aead_decrypt(net, aead, *skb, b);
1852	rcu_read_unlock();
1853
1854exit:
1855	stats = ((rx) ?: tx)->stats;
1856	switch (rc) {
1857	case 0:
1858		this_cpu_inc(stats->stat[STAT_OK]);
1859		break;
1860	case -EINPROGRESS:
1861	case -EBUSY:
1862		this_cpu_inc(stats->stat[STAT_ASYNC]);
1863		*skb = NULL;
1864		return rc;
1865	default:
1866		this_cpu_inc(stats->stat[STAT_NOK]);
1867		if (rc == -ENOKEY) {
1868			kfree_skb(*skb);
1869			*skb = NULL;
1870			if (rx) {
1871				/* Mark rx->nokey only if we dont have a
1872				 * pending received session key, nor a newer
1873				 * one i.e. in the next slot.
1874				 */
1875				n = key_next(tx_key);
1876				rx->nokey = !(rx->skey ||
1877					      rcu_access_pointer(rx->aead[n]));
1878				pr_debug_ratelimited("%s: nokey %d, key %d/%x\n",
1879						     rx->name, rx->nokey,
1880						     tx_key, rx->key.keys);
1881				tipc_node_put(rx->node);
1882			}
1883			this_cpu_inc(stats->stat[STAT_NOKEYS]);
1884			return rc;
1885		} else if (rc == -EBADMSG) {
1886			this_cpu_inc(stats->stat[STAT_BADMSGS]);
1887		}
1888		break;
1889	}
1890
1891	tipc_crypto_rcv_complete(net, aead, b, skb, rc);
1892	return rc;
1893}
1894
1895static void tipc_crypto_rcv_complete(struct net *net, struct tipc_aead *aead,
1896				     struct tipc_bearer *b,
1897				     struct sk_buff **skb, int err)
1898{
1899	struct tipc_skb_cb *skb_cb = TIPC_SKB_CB(*skb);
1900	struct tipc_crypto *rx = aead->crypto;
1901	struct tipc_aead *tmp = NULL;
1902	struct tipc_ehdr *ehdr;
1903	struct tipc_node *n;
 
 
1904
1905	/* Is this completed by TX? */
1906	if (unlikely(is_tx(aead->crypto))) {
1907		rx = skb_cb->tx_clone_ctx.rx;
1908		pr_debug("TX->RX(%s): err %d, aead %p, skb->next %p, flags %x\n",
1909			 (rx) ? tipc_node_get_id_str(rx->node) : "-", err, aead,
1910			 (*skb)->next, skb_cb->flags);
1911		pr_debug("skb_cb [recurs %d, last %p], tx->aead [%p %p %p]\n",
1912			 skb_cb->tx_clone_ctx.recurs, skb_cb->tx_clone_ctx.last,
1913			 aead->crypto->aead[1], aead->crypto->aead[2],
1914			 aead->crypto->aead[3]);
 
 
1915		if (unlikely(err)) {
1916			if (err == -EBADMSG && (*skb)->next)
1917				tipc_rcv(net, (*skb)->next, b);
1918			goto free_skb;
1919		}
1920
1921		if (likely((*skb)->next)) {
1922			kfree_skb((*skb)->next);
1923			(*skb)->next = NULL;
1924		}
1925		ehdr = (struct tipc_ehdr *)(*skb)->data;
1926		if (!rx) {
1927			WARN_ON(ehdr->user != LINK_CONFIG);
1928			n = tipc_node_create(net, 0, ehdr->id, 0xffffu, 0,
1929					     true);
1930			rx = tipc_node_crypto_rx(n);
1931			if (unlikely(!rx))
1932				goto free_skb;
1933		}
1934
1935		/* Ignore cloning if it was TX master key */
1936		if (ehdr->tx_key == KEY_MASTER)
1937			goto rcv;
1938		if (tipc_aead_clone(&tmp, aead) < 0)
1939			goto rcv;
1940		WARN_ON(!refcount_inc_not_zero(&tmp->refcnt));
1941		if (tipc_crypto_key_attach(rx, tmp, ehdr->tx_key, false) < 0) {
1942			tipc_aead_free(&tmp->rcu);
1943			goto rcv;
1944		}
1945		tipc_aead_put(aead);
1946		aead = tmp;
1947	}
1948
1949	if (unlikely(err)) {
1950		tipc_aead_users_dec((struct tipc_aead __force __rcu *)aead, INT_MIN);
1951		goto free_skb;
1952	}
1953
1954	/* Set the RX key's user */
1955	tipc_aead_users_set((struct tipc_aead __force __rcu *)aead, 1);
1956
 
1957	/* Mark this point, RX works */
1958	rx->timer1 = jiffies;
1959
1960rcv:
1961	/* Remove ehdr & auth. tag prior to tipc_rcv() */
1962	ehdr = (struct tipc_ehdr *)(*skb)->data;
1963
1964	/* Mark this point, RX passive still works */
1965	if (rx->key.passive && ehdr->tx_key == rx->key.passive)
1966		rx->timer2 = jiffies;
1967
1968	skb_reset_network_header(*skb);
1969	skb_pull(*skb, tipc_ehdr_size(ehdr));
1970	pskb_trim(*skb, (*skb)->len - aead->authsize);
1971
1972	/* Validate TIPCv2 message */
1973	if (unlikely(!tipc_msg_validate(skb))) {
1974		pr_err_ratelimited("Packet dropped after decryption!\n");
1975		goto free_skb;
1976	}
1977
1978	/* Ok, everything's fine, try to synch own keys according to peers' */
1979	tipc_crypto_key_synch(rx, *skb);
 
1980
1981	/* Mark skb decrypted */
1982	skb_cb->decrypted = 1;
1983
1984	/* Clear clone cxt if any */
1985	if (likely(!skb_cb->tx_clone_deferred))
1986		goto exit;
1987	skb_cb->tx_clone_deferred = 0;
1988	memset(&skb_cb->tx_clone_ctx, 0, sizeof(skb_cb->tx_clone_ctx));
1989	goto exit;
1990
1991free_skb:
1992	kfree_skb(*skb);
1993	*skb = NULL;
1994
1995exit:
1996	tipc_aead_put(aead);
1997	if (rx)
1998		tipc_node_put(rx->node);
1999}
2000
2001static void tipc_crypto_do_cmd(struct net *net, int cmd)
2002{
2003	struct tipc_net *tn = tipc_net(net);
2004	struct tipc_crypto *tx = tn->crypto_tx, *rx;
2005	struct list_head *p;
2006	unsigned int stat;
2007	int i, j, cpu;
2008	char buf[200];
2009
2010	/* Currently only one command is supported */
2011	switch (cmd) {
2012	case 0xfff1:
2013		goto print_stats;
2014	default:
2015		return;
2016	}
2017
2018print_stats:
2019	/* Print a header */
2020	pr_info("\n=============== TIPC Crypto Statistics ===============\n\n");
2021
2022	/* Print key status */
2023	pr_info("Key status:\n");
2024	pr_info("TX(%7.7s)\n%s", tipc_own_id_string(net),
2025		tipc_crypto_key_dump(tx, buf));
2026
2027	rcu_read_lock();
2028	for (p = tn->node_list.next; p != &tn->node_list; p = p->next) {
2029		rx = tipc_node_crypto_rx_by_list(p);
2030		pr_info("RX(%7.7s)\n%s", tipc_node_get_id_str(rx->node),
2031			tipc_crypto_key_dump(rx, buf));
2032	}
2033	rcu_read_unlock();
2034
2035	/* Print crypto statistics */
2036	for (i = 0, j = 0; i < MAX_STATS; i++)
2037		j += scnprintf(buf + j, 200 - j, "|%11s ", hstats[i]);
2038	pr_info("Counter     %s", buf);
2039
2040	memset(buf, '-', 115);
2041	buf[115] = '\0';
2042	pr_info("%s\n", buf);
2043
2044	j = scnprintf(buf, 200, "TX(%7.7s) ", tipc_own_id_string(net));
2045	for_each_possible_cpu(cpu) {
2046		for (i = 0; i < MAX_STATS; i++) {
2047			stat = per_cpu_ptr(tx->stats, cpu)->stat[i];
2048			j += scnprintf(buf + j, 200 - j, "|%11d ", stat);
2049		}
2050		pr_info("%s", buf);
2051		j = scnprintf(buf, 200, "%12s", " ");
2052	}
2053
2054	rcu_read_lock();
2055	for (p = tn->node_list.next; p != &tn->node_list; p = p->next) {
2056		rx = tipc_node_crypto_rx_by_list(p);
2057		j = scnprintf(buf, 200, "RX(%7.7s) ",
2058			      tipc_node_get_id_str(rx->node));
2059		for_each_possible_cpu(cpu) {
2060			for (i = 0; i < MAX_STATS; i++) {
2061				stat = per_cpu_ptr(rx->stats, cpu)->stat[i];
2062				j += scnprintf(buf + j, 200 - j, "|%11d ",
2063					       stat);
2064			}
2065			pr_info("%s", buf);
2066			j = scnprintf(buf, 200, "%12s", " ");
2067		}
2068	}
2069	rcu_read_unlock();
2070
2071	pr_info("\n======================== Done ========================\n");
2072}
2073
2074static char *tipc_crypto_key_dump(struct tipc_crypto *c, char *buf)
2075{
2076	struct tipc_key key = c->key;
2077	struct tipc_aead *aead;
2078	int k, i = 0;
2079	char *s;
2080
2081	for (k = KEY_MIN; k <= KEY_MAX; k++) {
2082		if (k == KEY_MASTER) {
2083			if (is_rx(c))
2084				continue;
2085			if (time_before(jiffies,
2086					c->timer2 + TIPC_TX_GRACE_PERIOD))
2087				s = "ACT";
2088			else
2089				s = "PAS";
2090		} else {
2091			if (k == key.passive)
2092				s = "PAS";
2093			else if (k == key.active)
2094				s = "ACT";
2095			else if (k == key.pending)
2096				s = "PEN";
2097			else
2098				s = "-";
2099		}
2100		i += scnprintf(buf + i, 200 - i, "\tKey%d: %s", k, s);
2101
2102		rcu_read_lock();
2103		aead = rcu_dereference(c->aead[k]);
2104		if (aead)
2105			i += scnprintf(buf + i, 200 - i,
2106				       "{\"0x...%s\", \"%s\"}/%d:%d",
2107				       aead->hint,
2108				       (aead->mode == CLUSTER_KEY) ? "c" : "p",
2109				       atomic_read(&aead->users),
2110				       refcount_read(&aead->refcnt));
2111		rcu_read_unlock();
2112		i += scnprintf(buf + i, 200 - i, "\n");
2113	}
2114
2115	if (is_rx(c))
2116		i += scnprintf(buf + i, 200 - i, "\tPeer RX active: %d\n",
2117			       atomic_read(&c->peer_rx_active));
2118
2119	return buf;
2120}
2121
 
2122static char *tipc_key_change_dump(struct tipc_key old, struct tipc_key new,
2123				  char *buf)
2124{
2125	struct tipc_key *key = &old;
2126	int k, i = 0;
2127	char *s;
2128
2129	/* Output format: "[%s %s %s] -> [%s %s %s]", max len = 32 */
2130again:
2131	i += scnprintf(buf + i, 32 - i, "[");
2132	for (k = KEY_1; k <= KEY_3; k++) {
2133		if (k == key->passive)
2134			s = "pas";
2135		else if (k == key->active)
2136			s = "act";
2137		else if (k == key->pending)
2138			s = "pen";
2139		else
2140			s = "-";
2141		i += scnprintf(buf + i, 32 - i,
2142			       (k != KEY_3) ? "%s " : "%s", s);
2143	}
2144	if (key != &new) {
2145		i += scnprintf(buf + i, 32 - i, "] -> ");
2146		key = &new;
2147		goto again;
2148	}
2149	i += scnprintf(buf + i, 32 - i, "]");
2150	return buf;
2151}
2152
2153/**
2154 * tipc_crypto_msg_rcv - Common 'MSG_CRYPTO' processing point
2155 * @net: the struct net
2156 * @skb: the receiving message buffer
2157 */
2158void tipc_crypto_msg_rcv(struct net *net, struct sk_buff *skb)
2159{
2160	struct tipc_crypto *rx;
2161	struct tipc_msg *hdr;
2162
2163	if (unlikely(skb_linearize(skb)))
2164		goto exit;
2165
2166	hdr = buf_msg(skb);
2167	rx = tipc_node_crypto_rx_by_addr(net, msg_prevnode(hdr));
2168	if (unlikely(!rx))
2169		goto exit;
2170
2171	switch (msg_type(hdr)) {
2172	case KEY_DISTR_MSG:
2173		if (tipc_crypto_key_rcv(rx, hdr))
2174			goto exit;
2175		break;
2176	default:
2177		break;
2178	}
2179
2180	tipc_node_put(rx->node);
2181
2182exit:
2183	kfree_skb(skb);
2184}
2185
2186/**
2187 * tipc_crypto_key_distr - Distribute a TX key
2188 * @tx: the TX crypto
2189 * @key: the key's index
2190 * @dest: the destination tipc node, = NULL if distributing to all nodes
2191 *
2192 * Return: 0 in case of success, otherwise < 0
2193 */
2194int tipc_crypto_key_distr(struct tipc_crypto *tx, u8 key,
2195			  struct tipc_node *dest)
2196{
2197	struct tipc_aead *aead;
2198	u32 dnode = tipc_node_get_addr(dest);
2199	int rc = -ENOKEY;
2200
2201	if (!sysctl_tipc_key_exchange_enabled)
2202		return 0;
2203
2204	if (key) {
2205		rcu_read_lock();
2206		aead = tipc_aead_get(tx->aead[key]);
2207		if (likely(aead)) {
2208			rc = tipc_crypto_key_xmit(tx->net, aead->key,
2209						  aead->gen, aead->mode,
2210						  dnode);
2211			tipc_aead_put(aead);
2212		}
2213		rcu_read_unlock();
2214	}
2215
2216	return rc;
2217}
2218
2219/**
2220 * tipc_crypto_key_xmit - Send a session key
2221 * @net: the struct net
2222 * @skey: the session key to be sent
2223 * @gen: the key's generation
2224 * @mode: the key's mode
2225 * @dnode: the destination node address, = 0 if broadcasting to all nodes
2226 *
2227 * The session key 'skey' is packed in a TIPC v2 'MSG_CRYPTO/KEY_DISTR_MSG'
2228 * as its data section, then xmit-ed through the uc/bc link.
2229 *
2230 * Return: 0 in case of success, otherwise < 0
2231 */
2232static int tipc_crypto_key_xmit(struct net *net, struct tipc_aead_key *skey,
2233				u16 gen, u8 mode, u32 dnode)
2234{
2235	struct sk_buff_head pkts;
2236	struct tipc_msg *hdr;
2237	struct sk_buff *skb;
2238	u16 size, cong_link_cnt;
2239	u8 *data;
2240	int rc;
2241
2242	size = tipc_aead_key_size(skey);
2243	skb = tipc_buf_acquire(INT_H_SIZE + size, GFP_ATOMIC);
2244	if (!skb)
2245		return -ENOMEM;
2246
2247	hdr = buf_msg(skb);
2248	tipc_msg_init(tipc_own_addr(net), hdr, MSG_CRYPTO, KEY_DISTR_MSG,
2249		      INT_H_SIZE, dnode);
2250	msg_set_size(hdr, INT_H_SIZE + size);
2251	msg_set_key_gen(hdr, gen);
2252	msg_set_key_mode(hdr, mode);
2253
2254	data = msg_data(hdr);
2255	*((__be32 *)(data + TIPC_AEAD_ALG_NAME)) = htonl(skey->keylen);
2256	memcpy(data, skey->alg_name, TIPC_AEAD_ALG_NAME);
2257	memcpy(data + TIPC_AEAD_ALG_NAME + sizeof(__be32), skey->key,
2258	       skey->keylen);
2259
2260	__skb_queue_head_init(&pkts);
2261	__skb_queue_tail(&pkts, skb);
2262	if (dnode)
2263		rc = tipc_node_xmit(net, &pkts, dnode, 0);
2264	else
2265		rc = tipc_bcast_xmit(net, &pkts, &cong_link_cnt);
2266
2267	return rc;
2268}
2269
2270/**
2271 * tipc_crypto_key_rcv - Receive a session key
2272 * @rx: the RX crypto
2273 * @hdr: the TIPC v2 message incl. the receiving session key in its data
2274 *
2275 * This function retrieves the session key in the message from peer, then
2276 * schedules a RX work to attach the key to the corresponding RX crypto.
2277 *
2278 * Return: "true" if the key has been scheduled for attaching, otherwise
2279 * "false".
2280 */
2281static bool tipc_crypto_key_rcv(struct tipc_crypto *rx, struct tipc_msg *hdr)
2282{
2283	struct tipc_crypto *tx = tipc_net(rx->net)->crypto_tx;
2284	struct tipc_aead_key *skey = NULL;
2285	u16 key_gen = msg_key_gen(hdr);
2286	u16 size = msg_data_sz(hdr);
2287	u8 *data = msg_data(hdr);
2288
2289	spin_lock(&rx->lock);
2290	if (unlikely(rx->skey || (key_gen == rx->key_gen && rx->key.keys))) {
2291		pr_err("%s: key existed <%p>, gen %d vs %d\n", rx->name,
2292		       rx->skey, key_gen, rx->key_gen);
2293		goto exit;
2294	}
2295
2296	/* Allocate memory for the key */
2297	skey = kmalloc(size, GFP_ATOMIC);
2298	if (unlikely(!skey)) {
2299		pr_err("%s: unable to allocate memory for skey\n", rx->name);
2300		goto exit;
2301	}
2302
2303	/* Copy key from msg data */
2304	skey->keylen = ntohl(*((__be32 *)(data + TIPC_AEAD_ALG_NAME)));
2305	memcpy(skey->alg_name, data, TIPC_AEAD_ALG_NAME);
2306	memcpy(skey->key, data + TIPC_AEAD_ALG_NAME + sizeof(__be32),
2307	       skey->keylen);
2308
2309	/* Sanity check */
2310	if (unlikely(size != tipc_aead_key_size(skey))) {
2311		kfree(skey);
2312		skey = NULL;
2313		goto exit;
2314	}
2315
2316	rx->key_gen = key_gen;
2317	rx->skey_mode = msg_key_mode(hdr);
2318	rx->skey = skey;
2319	rx->nokey = 0;
2320	mb(); /* for nokey flag */
2321
2322exit:
2323	spin_unlock(&rx->lock);
2324
2325	/* Schedule the key attaching on this crypto */
2326	if (likely(skey && queue_delayed_work(tx->wq, &rx->work, 0)))
2327		return true;
2328
2329	return false;
2330}
2331
2332/**
2333 * tipc_crypto_work_rx - Scheduled RX works handler
2334 * @work: the struct RX work
2335 *
2336 * The function processes the previous scheduled works i.e. distributing TX key
2337 * or attaching a received session key on RX crypto.
2338 */
2339static void tipc_crypto_work_rx(struct work_struct *work)
2340{
2341	struct delayed_work *dwork = to_delayed_work(work);
2342	struct tipc_crypto *rx = container_of(dwork, struct tipc_crypto, work);
2343	struct tipc_crypto *tx = tipc_net(rx->net)->crypto_tx;
2344	unsigned long delay = msecs_to_jiffies(5000);
2345	bool resched = false;
2346	u8 key;
2347	int rc;
2348
2349	/* Case 1: Distribute TX key to peer if scheduled */
2350	if (atomic_cmpxchg(&rx->key_distr,
2351			   KEY_DISTR_SCHED,
2352			   KEY_DISTR_COMPL) == KEY_DISTR_SCHED) {
2353		/* Always pick the newest one for distributing */
2354		key = tx->key.pending ?: tx->key.active;
2355		rc = tipc_crypto_key_distr(tx, key, rx->node);
2356		if (unlikely(rc))
2357			pr_warn("%s: unable to distr key[%d] to %s, err %d\n",
2358				tx->name, key, tipc_node_get_id_str(rx->node),
2359				rc);
2360
2361		/* Sched for key_distr releasing */
2362		resched = true;
2363	} else {
2364		atomic_cmpxchg(&rx->key_distr, KEY_DISTR_COMPL, 0);
2365	}
2366
2367	/* Case 2: Attach a pending received session key from peer if any */
2368	if (rx->skey) {
2369		rc = tipc_crypto_key_init(rx, rx->skey, rx->skey_mode, false);
2370		if (unlikely(rc < 0))
2371			pr_warn("%s: unable to attach received skey, err %d\n",
2372				rx->name, rc);
2373		switch (rc) {
2374		case -EBUSY:
2375		case -ENOMEM:
2376			/* Resched the key attaching */
2377			resched = true;
2378			break;
2379		default:
2380			synchronize_rcu();
2381			kfree(rx->skey);
2382			rx->skey = NULL;
2383			break;
2384		}
2385	}
2386
2387	if (resched && queue_delayed_work(tx->wq, &rx->work, delay))
2388		return;
2389
2390	tipc_node_put(rx->node);
2391}
2392
2393/**
2394 * tipc_crypto_rekeying_sched - (Re)schedule rekeying w/o new interval
2395 * @tx: TX crypto
2396 * @changed: if the rekeying needs to be rescheduled with new interval
2397 * @new_intv: new rekeying interval (when "changed" = true)
2398 */
2399void tipc_crypto_rekeying_sched(struct tipc_crypto *tx, bool changed,
2400				u32 new_intv)
2401{
2402	unsigned long delay;
2403	bool now = false;
2404
2405	if (changed) {
2406		if (new_intv == TIPC_REKEYING_NOW)
2407			now = true;
2408		else
2409			tx->rekeying_intv = new_intv;
2410		cancel_delayed_work_sync(&tx->work);
2411	}
2412
2413	if (tx->rekeying_intv || now) {
2414		delay = (now) ? 0 : tx->rekeying_intv * 60 * 1000;
2415		queue_delayed_work(tx->wq, &tx->work, msecs_to_jiffies(delay));
2416	}
2417}
2418
2419/**
2420 * tipc_crypto_work_tx - Scheduled TX works handler
2421 * @work: the struct TX work
2422 *
2423 * The function processes the previous scheduled work, i.e. key rekeying, by
2424 * generating a new session key based on current one, then attaching it to the
2425 * TX crypto and finally distributing it to peers. It also re-schedules the
2426 * rekeying if needed.
2427 */
2428static void tipc_crypto_work_tx(struct work_struct *work)
2429{
2430	struct delayed_work *dwork = to_delayed_work(work);
2431	struct tipc_crypto *tx = container_of(dwork, struct tipc_crypto, work);
2432	struct tipc_aead_key *skey = NULL;
2433	struct tipc_key key = tx->key;
2434	struct tipc_aead *aead;
2435	int rc = -ENOMEM;
2436
2437	if (unlikely(key.pending))
2438		goto resched;
2439
2440	/* Take current key as a template */
2441	rcu_read_lock();
2442	aead = rcu_dereference(tx->aead[key.active ?: KEY_MASTER]);
2443	if (unlikely(!aead)) {
2444		rcu_read_unlock();
2445		/* At least one key should exist for securing */
2446		return;
2447	}
2448
2449	/* Lets duplicate it first */
2450	skey = kmemdup(aead->key, tipc_aead_key_size(aead->key), GFP_ATOMIC);
2451	rcu_read_unlock();
2452
2453	/* Now, generate new key, initiate & distribute it */
2454	if (likely(skey)) {
2455		rc = tipc_aead_key_generate(skey) ?:
2456		     tipc_crypto_key_init(tx, skey, PER_NODE_KEY, false);
2457		if (likely(rc > 0))
2458			rc = tipc_crypto_key_distr(tx, rc, NULL);
2459		kfree_sensitive(skey);
2460	}
2461
2462	if (unlikely(rc))
2463		pr_warn_ratelimited("%s: rekeying returns %d\n", tx->name, rc);
2464
2465resched:
2466	/* Re-schedule rekeying if any */
2467	tipc_crypto_rekeying_sched(tx, false, 0);
2468}