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Return success/failure result from tls_prf_sha256()

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The hash functions used within this function could fail in theory, so
provide the result to the caller.

Signed-off-by: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2019-06-27 18:08:16 +03:00
parent 3ec65a8e38
commit fd7778b5ed
2 changed files with 13 additions and 8 deletions
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15
src/crypto/sha256-tlsprf.c
View file

@ -26,8 +26,8 @@
* This function is used to derive new, cryptographically separate keys from a
* given key in TLS. This PRF is defined in RFC 2246, Chapter 5.
*/
void tls_prf_sha256(const u8 *secret, size_t secret_len, const char *label,
const u8 *seed, size_t seed_len, u8 *out, size_t outlen)
int tls_prf_sha256(const u8 *secret, size_t secret_len, const char *label,
const u8 *seed, size_t seed_len, u8 *out, size_t outlen)
{
size_t clen;
u8 A[SHA256_MAC_LEN];
@ -50,12 +50,15 @@ void tls_prf_sha256(const u8 *secret, size_t secret_len, const char *label,
* PRF(secret, label, seed) = P_SHA256(secret, label + seed)
*/
hmac_sha256_vector(secret, secret_len, 2, &addr[1], &len[1], A);
if (hmac_sha256_vector(secret, secret_len, 2, &addr[1], &len[1], A) < 0)
return -1;
pos = 0;
while (pos < outlen) {
hmac_sha256_vector(secret, secret_len, 3, addr, len, P);
hmac_sha256(secret, secret_len, A, SHA256_MAC_LEN, A);
if (hmac_sha256_vector(secret, secret_len, 3, addr, len, P) <
0 ||
hmac_sha256(secret, secret_len, A, SHA256_MAC_LEN, A) < 0)
return -1;
clen = outlen - pos;
if (clen > SHA256_MAC_LEN)
@ -63,4 +66,6 @@ void tls_prf_sha256(const u8 *secret, size_t secret_len, const char *label,
os_memcpy(out + pos, P, clen);
pos += clen;
}
return 0;
}

6
src/crypto/sha256.h
View file

@ -20,9 +20,9 @@ int sha256_prf(const u8 *key, size_t key_len, const char *label,
int sha256_prf_bits(const u8 *key, size_t key_len, const char *label,
const u8 *data, size_t data_len, u8 *buf,
size_t buf_len_bits);
void tls_prf_sha256(const u8 *secret, size_t secret_len,
const char *label, const u8 *seed, size_t seed_len,
u8 *out, size_t outlen);
int tls_prf_sha256(const u8 *secret, size_t secret_len,
const char *label, const u8 *seed, size_t seed_len,
u8 *out, size_t outlen);
int hmac_sha256_kdf(const u8 *secret, size_t secret_len,
const char *label, const u8 *seed, size_t seed_len,
u8 *out, size_t outlen);