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use TLS PRF
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Modify libssl to use EVP_PKEY TLS PRF.

Reviewed-by: Matt Caswell <matt@openssl.org>
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@snhenson
snhenson committed Jan 19, 2016
1 parent 1eff348 commit b7d60e7
Showing 1 changed file with 44 additions and 144 deletions.
188 changes: 44 additions & 144 deletions ssl/t1_enc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -141,155 +141,65 @@
# include <openssl/comp.h>
#endif
#include <openssl/evp.h>
#include <openssl/hmac.h>
#include <openssl/md5.h>
#include <openssl/kdf.h>
#include <openssl/rand.h>

/* seed1 through seed5 are virtually concatenated */
static int tls1_P_hash(const EVP_MD *md, const unsigned char *sec,
int sec_len,
const void *seed1, int seed1_len,
const void *seed2, int seed2_len,
const void *seed3, int seed3_len,
const void *seed4, int seed4_len,
const void *seed5, int seed5_len,
unsigned char *out, int olen)
{
int chunk;
size_t j;
EVP_MD_CTX *ctx = NULL, *ctx_tmp = NULL, *ctx_init = NULL;
EVP_PKEY *mac_key = NULL;
unsigned char A1[EVP_MAX_MD_SIZE];
size_t A1_len;
int ret = 0;

chunk = EVP_MD_size(md);
OPENSSL_assert(chunk >= 0);

ctx = EVP_MD_CTX_new();
ctx_tmp = EVP_MD_CTX_new();
ctx_init = EVP_MD_CTX_new();
if (ctx == NULL || ctx_tmp == NULL || ctx_init == NULL)
goto err;
EVP_MD_CTX_set_flags(ctx_init, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
mac_key = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL, sec, sec_len);
if (!mac_key)
goto err;
if (!EVP_DigestSignInit(ctx_init, NULL, md, NULL, mac_key))
goto err;
if (!EVP_MD_CTX_copy_ex(ctx, ctx_init))
goto err;
if (seed1 && !EVP_DigestSignUpdate(ctx, seed1, seed1_len))
goto err;
if (seed2 && !EVP_DigestSignUpdate(ctx, seed2, seed2_len))
goto err;
if (seed3 && !EVP_DigestSignUpdate(ctx, seed3, seed3_len))
goto err;
if (seed4 && !EVP_DigestSignUpdate(ctx, seed4, seed4_len))
goto err;
if (seed5 && !EVP_DigestSignUpdate(ctx, seed5, seed5_len))
goto err;
if (!EVP_DigestSignFinal(ctx, A1, &A1_len))
goto err;

for (;;) {
/* Reinit mac contexts */
if (!EVP_MD_CTX_copy_ex(ctx, ctx_init))
goto err;
if (!EVP_DigestSignUpdate(ctx, A1, A1_len))
goto err;
if (olen > chunk && !EVP_MD_CTX_copy_ex(ctx_tmp, ctx))
goto err;
if (seed1 && !EVP_DigestSignUpdate(ctx, seed1, seed1_len))
goto err;
if (seed2 && !EVP_DigestSignUpdate(ctx, seed2, seed2_len))
goto err;
if (seed3 && !EVP_DigestSignUpdate(ctx, seed3, seed3_len))
goto err;
if (seed4 && !EVP_DigestSignUpdate(ctx, seed4, seed4_len))
goto err;
if (seed5 && !EVP_DigestSignUpdate(ctx, seed5, seed5_len))
goto err;

if (olen > chunk) {
if (!EVP_DigestSignFinal(ctx, out, &j))
goto err;
out += j;
olen -= j;
/* calc the next A1 value */
if (!EVP_DigestSignFinal(ctx_tmp, A1, &A1_len))
goto err;
} else { /* last one */

if (!EVP_DigestSignFinal(ctx, A1, &A1_len))
goto err;
memcpy(out, A1, olen);
break;
}
}
ret = 1;
err:
EVP_PKEY_free(mac_key);
EVP_MD_CTX_free(ctx);
EVP_MD_CTX_free(ctx_tmp);
EVP_MD_CTX_free(ctx_init);
OPENSSL_cleanse(A1, sizeof(A1));
return ret;
}

/* seed1 through seed5 are virtually concatenated */
/* seed1 through seed5 are concatenated */
static int tls1_PRF(SSL *s,
const void *seed1, int seed1_len,
const void *seed2, int seed2_len,
const void *seed3, int seed3_len,
const void *seed4, int seed4_len,
const void *seed5, int seed5_len,
const unsigned char *sec, int slen,
unsigned char *out1, unsigned char *out2, int olen)
unsigned char *out, int olen)
{
const EVP_MD *md = ssl_prf_md(s);
EVP_PKEY_CTX *pctx = NULL;

int ret = 0;
size_t outlen = olen;

if (md == NULL) {
/* Should never happen */
SSLerr(SSL_F_TLS1_PRF, ERR_R_INTERNAL_ERROR);
return 0;
}
if (EVP_MD_type(md) == NID_md5_sha1) {
int i;
if (!tls1_P_hash(EVP_md5(), sec, slen/2 + (slen & 1),
seed1, seed1_len, seed2, seed2_len, seed3,
seed3_len, seed4, seed4_len, seed5, seed5_len,
out1, olen))
return 0;
if (!tls1_P_hash(EVP_sha1(), sec + slen/2, slen/2 + (slen & 1),
seed1, seed1_len, seed2, seed2_len, seed3,
seed3_len, seed4, seed4_len, seed5, seed5_len,
out2, olen))
return 0;
for (i = 0; i < olen; i++)
out1[i] ^= out2[i];
return 1;
}
memset(out2, 0, olen);
if (!tls1_P_hash(md, sec, slen,
seed1, seed1_len, seed2, seed2_len, seed3,
seed3_len, seed4, seed4_len, seed5, seed5_len,
out1, olen))
return 0;
pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_TLS1_PRF, NULL);
if (pctx == NULL || EVP_PKEY_derive_init(pctx) <= 0
|| EVP_PKEY_CTX_set_tls1_prf_md(pctx, md) <= 0
|| EVP_PKEY_CTX_set1_tls1_prf_secret(pctx, sec, slen) <= 0)
goto err;

return 1;
if (EVP_PKEY_CTX_add1_tls1_prf_seed(pctx, seed1, seed1_len) <= 0)
goto err;
if (EVP_PKEY_CTX_add1_tls1_prf_seed(pctx, seed2, seed2_len) <= 0)
goto err;
if (EVP_PKEY_CTX_add1_tls1_prf_seed(pctx, seed3, seed3_len) <= 0)
goto err;
if (EVP_PKEY_CTX_add1_tls1_prf_seed(pctx, seed4, seed4_len) <= 0)
goto err;
if (EVP_PKEY_CTX_add1_tls1_prf_seed(pctx, seed5, seed5_len) <= 0)
goto err;

if (EVP_PKEY_derive(pctx, out, &outlen) <= 0)
goto err;
ret = 1;

err:
EVP_PKEY_CTX_free(pctx);
return ret;
}

static int tls1_generate_key_block(SSL *s, unsigned char *km,
unsigned char *tmp, int num)
static int tls1_generate_key_block(SSL *s, unsigned char *km, int num)
{
int ret;
ret = tls1_PRF(s,
TLS_MD_KEY_EXPANSION_CONST,
TLS_MD_KEY_EXPANSION_CONST_SIZE, s->s3->server_random,
SSL3_RANDOM_SIZE, s->s3->client_random, SSL3_RANDOM_SIZE,
NULL, 0, NULL, 0, s->session->master_key,
s->session->master_key_length, km, tmp, num);
s->session->master_key_length, km, num);

return ret;
}
Expand Down Expand Up @@ -550,7 +460,7 @@ int tls1_change_cipher_state(SSL *s, int which)

int tls1_setup_key_block(SSL *s)
{
unsigned char *p1, *p2 = NULL;
unsigned char *p;
const EVP_CIPHER *c;
const EVP_MD *hash;
int num;
Expand Down Expand Up @@ -578,19 +488,14 @@ int tls1_setup_key_block(SSL *s)

ssl3_cleanup_key_block(s);

if ((p1 = OPENSSL_malloc(num)) == NULL) {
if ((p = OPENSSL_malloc(num)) == NULL) {
SSLerr(SSL_F_TLS1_SETUP_KEY_BLOCK, ERR_R_MALLOC_FAILURE);
goto err;
}

s->s3->tmp.key_block_length = num;
s->s3->tmp.key_block = p1;
s->s3->tmp.key_block = p;

if ((p2 = OPENSSL_malloc(num)) == NULL) {
SSLerr(SSL_F_TLS1_SETUP_KEY_BLOCK, ERR_R_MALLOC_FAILURE);
OPENSSL_free(p1);
goto err;
}
#ifdef TLS_DEBUG
printf("client random\n");
{
Expand All @@ -614,7 +519,7 @@ int tls1_setup_key_block(SSL *s)
((z + 1) % 16) ? ' ' : '\n');
}
#endif
if (!tls1_generate_key_block(s, p1, p2, num))
if (!tls1_generate_key_block(s, p, num))
goto err;
#ifdef TLS_DEBUG
printf("\nkey block\n");
Expand Down Expand Up @@ -646,7 +551,6 @@ int tls1_setup_key_block(SSL *s)

ret = 1;
err:
OPENSSL_clear_free(p2, num);
return (ret);
}

Expand All @@ -655,7 +559,6 @@ int tls1_final_finish_mac(SSL *s, const char *str, int slen,
{
int hashlen;
unsigned char hash[EVP_MAX_MD_SIZE];
unsigned char buf2[12];

if (!ssl3_digest_cached_records(s, 0))
return 0;
Expand All @@ -665,21 +568,17 @@ int tls1_final_finish_mac(SSL *s, const char *str, int slen,
if (hashlen == 0)
return 0;

if (!tls1_PRF(s,
str, slen, hash, hashlen, NULL, 0, NULL, 0, NULL, 0,
if (!tls1_PRF(s, str, slen, hash, hashlen, NULL, 0, NULL, 0, NULL, 0,
s->session->master_key, s->session->master_key_length,
out, buf2, sizeof buf2))
out, TLS1_FINISH_MAC_LENGTH))
return 0;
OPENSSL_cleanse(hash, hashlen);
OPENSSL_cleanse(buf2, sizeof(buf2));
return sizeof(buf2);
return TLS1_FINISH_MAC_LENGTH;
}

int tls1_generate_master_secret(SSL *s, unsigned char *out, unsigned char *p,
int len)
{
unsigned char buff[SSL_MAX_MASTER_KEY_LENGTH];

if (s->session->flags & SSL_SESS_FLAG_EXTMS) {
unsigned char hash[EVP_MAX_MD_SIZE * 2];
int hashlen;
Expand All @@ -701,7 +600,8 @@ int tls1_generate_master_secret(SSL *s, unsigned char *out, unsigned char *p,
hash, hashlen,
NULL, 0,
NULL, 0,
NULL, 0, p, len, s->session->master_key, buff, sizeof buff);
NULL, 0, p, len, s->session->master_key,
SSL3_MASTER_SECRET_SIZE);
OPENSSL_cleanse(hash, hashlen);
} else {
tls1_PRF(s,
Expand All @@ -710,9 +610,9 @@ int tls1_generate_master_secret(SSL *s, unsigned char *out, unsigned char *p,
s->s3->client_random, SSL3_RANDOM_SIZE,
NULL, 0,
s->s3->server_random, SSL3_RANDOM_SIZE,
NULL, 0, p, len, s->session->master_key, buff, sizeof buff);
NULL, 0, p, len, s->session->master_key,
SSL3_MASTER_SECRET_SIZE);
}
OPENSSL_cleanse(buff, sizeof buff);
#ifdef SSL_DEBUG
fprintf(stderr, "Premaster Secret:\n");
BIO_dump_fp(stderr, (char *)p, len);
Expand Down Expand Up @@ -817,7 +717,7 @@ int tls1_export_keying_material(SSL *s, unsigned char *out, size_t olen,
NULL, 0,
NULL, 0,
s->session->master_key, s->session->master_key_length,
out, buff, olen);
out, olen);

goto ret;
err1:
Expand Down

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