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crypto.c
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crypto.c
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// 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
* @tfm: cipher handle/key
* @list: linked 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
* @stat: array of 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
* @flags: combined flags field
* @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 { \
struct tipc_aead *__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
* @ukey: pointer to user key data
* @info: netlink info pointer
*/
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
* @aead: the AEAD key pointer
*/
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);
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 ^= __be32_to_cpu(ehdr->addr);
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 ^= __be32_to_cpu(ehdr->addr);
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;
}