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mptcp: Use kernel crypto API for MPTCP HMAC
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First test to study usage of kernel crypto APIs to implement
'mptcp_hmac_sha1' in MPTCP.

Signed-off-by: Fabrizio Demaria <fabrizio.demaria@intel.com>
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@fabriziodemaria
fabriziodemaria committed Dec 2, 2015
1 parent 4b7f599 commit 9c0495f
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Showing 5 changed files with 96 additions and 69 deletions.
12 changes: 11 additions & 1 deletion include/net/mptcp.h
View file
Expand Up @@ -344,6 +344,10 @@ struct mptcp_cb {
u32 orig_window_clamp;
};

struct mptcp_hmacsha1_pool {
struct hash_desc hmacsha1_desc;
};

#define MPTCP_SUB_CAPABLE 0
#define MPTCP_SUB_LEN_CAPABLE_SYN 12
#define MPTCP_SUB_LEN_CAPABLE_SYN_ALIGN 12
Expand Down Expand Up @@ -826,8 +830,9 @@ void mptcp_select_initial_window(int __space, __u32 mss, __u32 *rcv_wnd,
const struct sock *sk);
unsigned int mptcp_current_mss(struct sock *meta_sk);
int mptcp_select_size(const struct sock *meta_sk, bool sg);
void mptcp_alloc_hmacsha1_pool(void);
void mptcp_key_sha1(u64 key, u32 *token, u64 *idsn);
void mptcp_hmac_sha1(u8 *key_1, u8 *key_2, u32 *hash_out, int arg_num, ...);
void mptcp_hmac_sha1(u8 *key_1, u8 *key_2, u8 *hash_out, int arg_num, ...);
void mptcp_clean_rtx_infinite(const struct sk_buff *skb, struct sock *sk);
void mptcp_fin(struct sock *meta_sk);
void mptcp_retransmit_timer(struct sock *meta_sk);
Expand Down Expand Up @@ -906,6 +911,11 @@ void mptcp_get_default_scheduler(char *name);
int mptcp_set_default_scheduler(const char *name);
extern struct mptcp_sched_ops mptcp_sched_default;

static inline void mptcp_put_hmacsha1_pool(void)
{
local_bh_enable();
}

/* Initializes function-pointers and MPTCP-flags */
static inline void mptcp_init_tcp_sock(struct sock *sk)
{
Expand Down
1 change: 1 addition & 0 deletions net/ipv4/tcp.c
View file
Expand Up @@ -443,6 +443,7 @@ void tcp_init_sock(struct sock *sk)

/* Initialize MPTCP-specific stuff and function-pointers */
mptcp_init_tcp_sock(sk);
mptcp_alloc_hmacsha1_pool();

local_bh_disable();
sock_update_memcg(sk);
Expand Down
140 changes: 78 additions & 62 deletions net/mptcp/mptcp_ctrl.c
View file
Expand Up @@ -76,6 +76,10 @@ bool mptcp_init_failed __read_mostly;
struct static_key mptcp_static_key = STATIC_KEY_INIT_FALSE;
EXPORT_SYMBOL(mptcp_static_key);

bool mptcp_hmacsha1_pool_populated;
static DEFINE_PER_CPU(struct mptcp_hmacsha1_pool, mptcp_hmacsha1_pool);
static DEFINE_MUTEX(mptcp_hmacsha1_mutex);

static int proc_mptcp_path_manager(struct ctl_table *ctl, int write,
void __user *buffer, size_t *lenp,
loff_t *ppos)
Expand Down Expand Up @@ -380,6 +384,50 @@ static void mptcp_set_key_sk(const struct sock *sk)
&tp->mptcp_loc_token, NULL);
}

static void __mptcp_alloc_hmacsha1_pool(void)
{
int cpu;

for_each_possible_cpu(cpu) {
if (!per_cpu(mptcp_hmacsha1_pool, cpu).hmacsha1_desc.tfm) {
struct crypto_hash *hash;

hash = crypto_alloc_hash("hmac(sha1)", 0, CRYPTO_ALG_ASYNC);
if (IS_ERR_OR_NULL(hash))
return;
per_cpu(mptcp_hmacsha1_pool, cpu).hmacsha1_desc.tfm = hash;
}
}
/* before setting mptcp_hmacsha1_pool_populated, we must commit all
* writes to memory. See smp_rmb() in mptcp_get_hmacsha1_pool()
*/
smp_wmb();
mptcp_hmacsha1_pool_populated = true;
}

void mptcp_alloc_hmacsha1_pool(void)
{
if (unlikely(!mptcp_hmacsha1_pool_populated)) {
mutex_lock(&mptcp_hmacsha1_mutex);
if (!mptcp_hmacsha1_pool_populated)
__mptcp_alloc_hmacsha1_pool();
mutex_unlock(&mptcp_hmacsha1_mutex);
}
}
EXPORT_SYMBOL(mptcp_alloc_hmacsha1_pool);

struct mptcp_hmacsha1_pool *mptcp_get_hmacsha1_pool(void)
{
local_bh_disable();
if (mptcp_hmacsha1_pool_populated) {
/* coupled with smp_wmb() in __mptcp_alloc_hmacsha1_pool() */
smp_rmb();
return this_cpu_ptr(&mptcp_hmacsha1_pool);
}
local_bh_enable();
return NULL;
}

#ifdef HAVE_JUMP_LABEL
/* We are not allowed to call static_key_slow_dec() from irq context
* If mptcp_enable/disable_static_key() is called from irq context,
Expand Down Expand Up @@ -798,81 +846,49 @@ void mptcp_key_sha1(u64 key, u32 *token, u64 *idsn)
*idsn = *((u64 *)&mptcp_hashed_key[3]);
}

void mptcp_hmac_sha1(u8 *key_1, u8 *key_2, u32 *hash_out, int arg_num, ...)
void mptcp_hmac_sha1(u8 *key_1, u8 *key_2, u8 *hash_out, int arg_num, ...)
{
u32 workspace[SHA_WORKSPACE_WORDS];
u8 input[128]; /* 2 512-bit blocks */
struct mptcp_hmacsha1_pool *sp;
struct scatterlist sg;
u8 key[16];
int i;
int index;
int length;
u8 *msg;
va_list list;

memset(workspace, 0, sizeof(workspace));
/* Initialize result placeholder */
memset(hash_out, 0, sizeof(hash_out));
sp = mptcp_get_hmacsha1_pool();
if (!sp)
goto clear_hmac_noput;
sp->hmacsha1_desc.flags = 0;

memcpy(&key[0], key_1, 8);
memcpy(&key[8], key_2, 8);

/* Generate key xored with ipad */
memset(input, 0x36, 64);
for (i = 0; i < 8; i++)
input[i] ^= key_1[i];
for (i = 0; i < 8; i++)
input[i + 8] ^= key_2[i];
if (crypto_hash_setkey(sp->hmacsha1_desc.tfm, (u8 *)key, 16))
goto clear_hmac;
if (crypto_hash_init(&sp->hmacsha1_desc))
goto clear_hmac;

va_start(list, arg_num);
index = 64;
for (i = 0; i < arg_num; i++) {
for (i = 0; i < (arg_num); i++) {
length = va_arg(list, int);
msg = va_arg(list, u8 *);
if (index + length > 125) {
/* The message is too long */
return;
}
memcpy(&input[index], msg, length);
index += length;
sg_init_one(&sg, msg, length);
if (crypto_hash_update(&sp->hmacsha1_desc, &sg, length))
goto clear_hmac;
}
va_end(list);

input[index] = 0x80; /* Padding: First bit after message = 1 */
memset(&input[index + 1], 0, (126 - index));

/* Padding: Length of the message = 512 + message length (bits) */
input[126] = 0x02;
input[127] = ((index - 64) * 8); /* Message length (bits) */

sha_init(hash_out);
sha_transform(hash_out, input, workspace);
memset(workspace, 0, sizeof(workspace));

sha_transform(hash_out, &input[64], workspace);
memset(workspace, 0, sizeof(workspace));

for (i = 0; i < 5; i++)
hash_out[i] = cpu_to_be32(hash_out[i]);

/* Prepare second part of hmac */
memset(input, 0x5C, 64);
for (i = 0; i < 8; i++)
input[i] ^= key_1[i];
for (i = 0; i < 8; i++)
input[i + 8] ^= key_2[i];

memcpy(&input[64], hash_out, 20);
input[84] = 0x80;
memset(&input[85], 0, 41);

/* Padding: Length of the message = 512 + 160 bits */
input[126] = 0x02;
input[127] = 0xA0;

sha_init(hash_out);
sha_transform(hash_out, input, workspace);
memset(workspace, 0, sizeof(workspace));

sha_transform(hash_out, &input[64], workspace);
if (crypto_hash_final(&sp->hmacsha1_desc, hash_out))
goto clear_hmac;
mptcp_put_hmacsha1_pool();
return;

for (i = 0; i < 5; i++)
hash_out[i] = cpu_to_be32(hash_out[i]);
clear_hmac:
mptcp_put_hmacsha1_pool();
clear_hmac_noput:
memset((u8 *)hash_out, 0, 20);
return;
}

static void mptcp_mpcb_inherit_sockopts(struct sock *meta_sk, struct sock *master_sk)
Expand Down Expand Up @@ -2045,7 +2061,7 @@ struct sock *mptcp_check_req_child(struct sock *meta_sk, struct sock *child,

mptcp_hmac_sha1((u8 *)&mpcb->mptcp_rem_key,
(u8 *)&mpcb->mptcp_loc_key,
(u32 *)hash_mac_check, 2,
(u8 *)hash_mac_check, 2,
4, (u8 *)&mtreq->mptcp_rem_nonce,
4, (u8 *)&mtreq->mptcp_loc_nonce);

Expand Down Expand Up @@ -2278,7 +2294,7 @@ void mptcp_join_reqsk_init(struct mptcp_cb *mpcb, const struct request_sock *req

mptcp_hmac_sha1((u8 *)&mpcb->mptcp_loc_key,
(u8 *)&mpcb->mptcp_rem_key,
(u32 *)mptcp_hash_mac, 2,
(u8 *)mptcp_hash_mac, 2,
4, (u8 *)&mtreq->mptcp_loc_nonce,
4, (u8 *)&mtreq->mptcp_rem_nonce);
mtreq->mptcp_hash_tmac = *(u64 *)mptcp_hash_mac;
Expand Down
4 changes: 2 additions & 2 deletions net/mptcp/mptcp_fullmesh.c
View file
Expand Up @@ -1570,7 +1570,7 @@ static void full_mesh_addr_signal(struct sock *sk, unsigned *size,
*(u64 *)no_key = 0;
mptcp_hmac_sha1((u8 *)&mpcb->mptcp_loc_key,
(u8 *)no_key,
(u32 *)mptcp_hash_mac, 2,
(u8 *)mptcp_hash_mac, 2,
1, (u8 *)&mptcp_local->locaddr4[ind].loc4_id,
4, (u8 *)&opts->add_addr4.addr.s_addr);
opts->add_addr4.trunc_mac = *(u64 *)mptcp_hash_mac;
Expand Down Expand Up @@ -1611,7 +1611,7 @@ static void full_mesh_addr_signal(struct sock *sk, unsigned *size,
*(u64 *)no_key = 0;
mptcp_hmac_sha1((u8 *)&mpcb->mptcp_loc_key,
(u8 *)no_key,
(u32 *)mptcp_hash_mac, 2,
(u8 *)mptcp_hash_mac, 2,
1, (u8 *)&mptcp_local->locaddr6[ind].loc6_id,
16, (u8 *)&opts->add_addr6.addr.s6_addr);
opts->add_addr6.trunc_mac = *(u64 *)mptcp_hash_mac;
Expand Down
8 changes: 4 additions & 4 deletions net/mptcp/mptcp_input.c
View file
Expand Up @@ -1940,7 +1940,7 @@ static void mptcp_handle_add_addr(const unsigned char *ptr, struct sock *sk)
}
mptcp_hmac_sha1((u8 *)&mpcb->mptcp_rem_key,
(u8 *)no_key,
(u32 *)hash_mac_check, msg_parts,
(u8 *)hash_mac_check, msg_parts,
1, (u8 *)&mpadd->addr_id,
4, (u8 *)&mpadd->u.v4.addr.s_addr,
2, (u8 *)&mpadd->u.v4.port);
Expand Down Expand Up @@ -1975,7 +1975,7 @@ static void mptcp_handle_add_addr(const unsigned char *ptr, struct sock *sk)
}
mptcp_hmac_sha1((u8 *)&mpcb->mptcp_rem_key,
(u8 *)no_key,
(u32 *)hash_mac_check, msg_parts,
(u8 *)hash_mac_check, msg_parts,
1, (u8 *)&mpadd->addr_id,
16, (u8 *)&mpadd->u.v6.addr.s6_addr,
2, (u8 *)&mpadd->u.v6.port);
Expand Down Expand Up @@ -2292,7 +2292,7 @@ int mptcp_rcv_synsent_state_process(struct sock *sk, struct sock **skptr,

mptcp_hmac_sha1((u8 *)&mpcb->mptcp_rem_key,
(u8 *)&mpcb->mptcp_loc_key,
(u32 *)hash_mac_check, 2,
(u8 *)hash_mac_check, 2,
4, (u8 *)&tp->mptcp->rx_opt.mptcp_recv_nonce,
4, (u8 *)&tp->mptcp->mptcp_loc_nonce);
if (memcmp(hash_mac_check,
Expand All @@ -2310,7 +2310,7 @@ int mptcp_rcv_synsent_state_process(struct sock *sk, struct sock **skptr,

mptcp_hmac_sha1((u8 *)&mpcb->mptcp_loc_key,
(u8 *)&mpcb->mptcp_rem_key,
(u32 *)&tp->mptcp->sender_mac[0], 2,
(u8 *)&tp->mptcp->sender_mac[0], 2,
4, (u8 *)&tp->mptcp->mptcp_loc_nonce,
4, (u8 *)&tp->mptcp->rx_opt.mptcp_recv_nonce);

Expand Down

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