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tls: in AES-CBC code, do not set key for every record - do it once

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function                                             old     new   delta
aes_setkey                                            16     212    +196
tls_handshake                                       1941    1977     +36
aes_encrypt_1                                        382     396     +14
xwrite_encrypted                                     605     604      -1
tls_xread_record                                     659     656      -3
aes_encrypt_one_block                                 65      59      -6
aes_cbc_encrypt                                      172     121     -51
aesgcm_setkey                                         58       -     -58
aes_cbc_decrypt                                      958     881     -77
KeyExpansion                                         188       -    -188
------------------------------------------------------------------------------
(add/remove: 0/2 grow/shrink: 3/5 up/down: 246/-384)         Total: -138 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2018-11-23 18:02:44 +01:00
parent 83e5c627e1
commit 5e4236d226
5 changed files with 28 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
networking/tls.c
View File

@ -758,7 +758,7 @@ static void xwrite_encrypted_and_hmac_signed(tls_state_t *tls, unsigned size, un
/* Encrypt content+MAC+padding in place */ /* Encrypt content+MAC+padding in place */
//optimize key setup //optimize key setup
aes_cbc_encrypt( aes_cbc_encrypt(
tls->client_write_key, tls->key_size, /* selects 128/256 */ &tls->aes_decrypt, /* selects 128/256 */
buf - AES_BLOCK_SIZE, /* IV */ buf - AES_BLOCK_SIZE, /* IV */
buf, size, /* plaintext */ buf, size, /* plaintext */
buf /* ciphertext */ buf /* ciphertext */
@ -1061,7 +1061,7 @@ static int tls_xread_record(tls_state_t *tls, const char *expected)
/* Decrypt content+MAC+padding, moving it over IV in the process */ /* Decrypt content+MAC+padding, moving it over IV in the process */
sz -= AES_BLOCK_SIZE; /* we will overwrite IV now */ sz -= AES_BLOCK_SIZE; /* we will overwrite IV now */
aes_cbc_decrypt( aes_cbc_decrypt(
tls->server_write_key, tls->key_size, /* selects 128/256 */ &tls->aes_decrypt, /* selects 128/256 */
p, /* IV */ p, /* IV */
p + AES_BLOCK_SIZE, sz, /* ciphertext */ p + AES_BLOCK_SIZE, sz, /* ciphertext */
p /* plaintext */ p /* plaintext */
@ -1934,8 +1934,14 @@ static void send_client_key_exchange(tls_state_t *tls)
dump_hex("client_write_IV:%s\n", dump_hex("client_write_IV:%s\n",
tls->client_write_IV, tls->IV_size tls->client_write_IV, tls->IV_size
); );
aesgcm_setkey(tls->H, &tls->aes_encrypt, tls->client_write_key, tls->key_size);
aes_setkey(&tls->aes_decrypt, tls->server_write_key, tls->key_size); aes_setkey(&tls->aes_decrypt, tls->server_write_key, tls->key_size);
aes_setkey(&tls->aes_encrypt, tls->client_write_key, tls->key_size);
{
uint8_t iv[AES_BLOCK_SIZE];
memset(iv, 0, AES_BLOCK_SIZE);
aes_encrypt_one_block(&tls->aes_encrypt, iv, tls->H);
}
} }
} }

32
networking/tls_aes.c
View File

@ -326,8 +326,11 @@ static void InvMixColumns(unsigned astate[16])
} }
} }
static void aes_encrypt_1(unsigned astate[16], unsigned rounds, const uint32_t *RoundKey) static void aes_encrypt_1(struct tls_aes *aes, unsigned astate[16])
{ {
unsigned rounds = aes->rounds;
const uint32_t *RoundKey = aes->key;
for (;;) { for (;;) {
AddRoundKey(astate, RoundKey); AddRoundKey(astate, RoundKey);
RoundKey += 4; RoundKey += 4;
@ -355,22 +358,19 @@ void FAST_FUNC aes_encrypt_one_block(struct tls_aes *aes, const void *data, void
for (i = 0; i < 16; i++) for (i = 0; i < 16; i++)
astate[i] = pt[i]; astate[i] = pt[i];
aes_encrypt_1(astate, aes->rounds, aes->key); aes_encrypt_1(aes, astate);
for (i = 0; i < 16; i++) for (i = 0; i < 16; i++)
ct[i] = astate[i]; ct[i] = astate[i];
} }
void FAST_FUNC aes_cbc_encrypt(const void *key, int klen, void *iv, const void *data, size_t len, void *dst) void FAST_FUNC aes_cbc_encrypt(struct tls_aes *aes, void *iv, const void *data, size_t len, void *dst)
{ {
uint32_t RoundKey[60];
uint8_t iv2[16]; uint8_t iv2[16];
unsigned rounds;
const uint8_t *pt = data; const uint8_t *pt = data;
uint8_t *ct = dst; uint8_t *ct = dst;
memcpy(iv2, iv, 16); memcpy(iv2, iv, 16);
rounds = KeyExpansion(RoundKey, key, klen);
while (len > 0) { while (len > 0) {
{ {
/* almost aes_encrypt_one_block(rounds, RoundKey, pt, ct); /* almost aes_encrypt_one_block(rounds, RoundKey, pt, ct);
@ -381,7 +381,7 @@ void FAST_FUNC aes_cbc_encrypt(const void *key, int klen, void *iv, const void *
unsigned astate[16]; unsigned astate[16];
for (i = 0; i < 16; i++) for (i = 0; i < 16; i++)
astate[i] = pt[i] ^ iv2[i]; astate[i] = pt[i] ^ iv2[i];
aes_encrypt_1(astate, rounds, RoundKey); aes_encrypt_1(aes, astate);
for (i = 0; i < 16; i++) for (i = 0; i < 16; i++)
iv2[i] = ct[i] = astate[i]; iv2[i] = ct[i] = astate[i];
} }
@ -391,8 +391,11 @@ void FAST_FUNC aes_cbc_encrypt(const void *key, int klen, void *iv, const void *
} }
} }
static void aes_decrypt_1(unsigned astate[16], unsigned rounds, const uint32_t *RoundKey) static void aes_decrypt_1(struct tls_aes *aes, unsigned astate[16])
{ {
unsigned rounds = aes->rounds;
const uint32_t *RoundKey = aes->key;
RoundKey += rounds * 4; RoundKey += rounds * 4;
AddRoundKey(astate, RoundKey); AddRoundKey(astate, RoundKey);
for (;;) { for (;;) {
@ -407,8 +410,10 @@ static void aes_decrypt_1(unsigned astate[16], unsigned rounds, const uint32_t *
} }
#if 0 //UNUSED #if 0 //UNUSED
static void aes_decrypt_one_block(unsigned rounds, const uint32_t *RoundKey, const void *data, void *dst) static void aes_decrypt_one_block(struct tls_aes *aes, const void *data, void *dst)
{ {
unsigned rounds = aes->rounds;
const uint32_t *RoundKey = aes->key;
unsigned astate[16]; unsigned astate[16];
unsigned i; unsigned i;
@ -417,25 +422,22 @@ static void aes_decrypt_one_block(unsigned rounds, const uint32_t *RoundKey, con
for (i = 0; i < 16; i++) for (i = 0; i < 16; i++)
astate[i] = ct[i]; astate[i] = ct[i];
aes_decrypt_1(astate, rounds, RoundKey); aes_decrypt_1(aes, astate);
for (i = 0; i < 16; i++) for (i = 0; i < 16; i++)
pt[i] = astate[i]; pt[i] = astate[i];
} }
#endif #endif
void FAST_FUNC aes_cbc_decrypt(const void *key, int klen, void *iv, const void *data, size_t len, void *dst) void FAST_FUNC aes_cbc_decrypt(struct tls_aes *aes, void *iv, const void *data, size_t len, void *dst)
{ {
uint32_t RoundKey[60];
uint8_t iv2[16]; uint8_t iv2[16];
uint8_t iv3[16]; uint8_t iv3[16];
unsigned rounds;
uint8_t *ivbuf; uint8_t *ivbuf;
uint8_t *ivnext; uint8_t *ivnext;
const uint8_t *ct = data; const uint8_t *ct = data;
uint8_t *pt = dst; uint8_t *pt = dst;
rounds = KeyExpansion(RoundKey, key, klen);
ivbuf = memcpy(iv2, iv, 16); ivbuf = memcpy(iv2, iv, 16);
while (len) { while (len) {
ivnext = (ivbuf==iv2) ? iv3 : iv2; ivnext = (ivbuf==iv2) ? iv3 : iv2;
@ -447,7 +449,7 @@ void FAST_FUNC aes_cbc_decrypt(const void *key, int klen, void *iv, const void *
unsigned astate[16]; unsigned astate[16];
for (i = 0; i < 16; i++) for (i = 0; i < 16; i++)
ivnext[i] = astate[i] = ct[i]; ivnext[i] = astate[i] = ct[i];
aes_decrypt_1(astate, rounds, RoundKey); aes_decrypt_1(aes, astate);
for (i = 0; i < 16; i++) for (i = 0; i < 16; i++)
pt[i] = astate[i] ^ ivbuf[i]; pt[i] = astate[i] ^ ivbuf[i];
} }

4
networking/tls_aes.h
View File

@ -10,5 +10,5 @@ void aes_setkey(struct tls_aes *aes, const void *key, unsigned key_len) FAST_FUN
void aes_encrypt_one_block(struct tls_aes *aes, const void *data, void *dst) FAST_FUNC; void aes_encrypt_one_block(struct tls_aes *aes, const void *data, void *dst) FAST_FUNC;
void aes_cbc_encrypt(const void *key, int klen, void *iv, const void *data, size_t len, void *dst) FAST_FUNC; void aes_cbc_encrypt(struct tls_aes *aes, void *iv, const void *data, size_t len, void *dst) FAST_FUNC;
void aes_cbc_decrypt(const void *key, int klen, void *iv, const void *data, size_t len, void *dst) FAST_FUNC; void aes_cbc_decrypt(struct tls_aes *aes, void *iv, const void *data, size_t len, void *dst) FAST_FUNC;

10
networking/tls_aesgcm.c
View File

@ -136,13 +136,3 @@ void FAST_FUNC aesgcm_GHASH(byte* h, const byte* a, unsigned aSz, const byte* c,
/* Copy the result into s. */ /* Copy the result into s. */
XMEMCPY(s, x, sSz); XMEMCPY(s, x, sSz);
} }
void FAST_FUNC aesgcm_setkey(uint8_t H[16], struct tls_aes *aes, const byte* key, unsigned len)
{
byte iv[AES_BLOCK_SIZE];
aes_setkey(aes, key, len);
memset(iv, 0, AES_BLOCK_SIZE);
aes_encrypt_one_block(aes, iv, H);
}

2
networking/tls_aesgcm.h
View File

@ -11,5 +11,3 @@ void aesgcm_GHASH(uint8_t* h,
const uint8_t* c, unsigned cSz, const uint8_t* c, unsigned cSz,
uint8_t* s, unsigned sSz uint8_t* s, unsigned sSz
) FAST_FUNC; ) FAST_FUNC;
void aesgcm_setkey(uint8_t H[16], struct tls_aes *aes, const uint8_t* key, unsigned len) FAST_FUNC;