diff options
Diffstat (limited to 'src/openvpn/crypto.c')
| -rw-r--r-- | src/openvpn/crypto.c | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/src/openvpn/crypto.c b/src/openvpn/crypto.c index ac2eecd..d9adf5b 100644 --- a/src/openvpn/crypto.c +++ b/src/openvpn/crypto.c @@ -65,6 +65,24 @@ #define CRYPT_ERROR(format) \ do { msg (D_CRYPT_ERRORS, "%s: " format, error_prefix); goto error_exit; } while (false) +/** + * As memcmp(), but constant-time. + * Returns 0 when data is equal, non-zero otherwise. + */ +static int +memcmp_constant_time (const void *a, const void *b, size_t size) { + const uint8_t * a1 = a; + const uint8_t * b1 = b; + int ret = 0; + size_t i; + + for (i = 0; i < size; i++) { + ret |= *a1++ ^ *b1++; + } + + return ret; +} + void openvpn_encrypt (struct buffer *buf, struct buffer work, const struct crypto_options *opt, @@ -244,7 +262,7 @@ openvpn_decrypt (struct buffer *buf, struct buffer work, hmac_ctx_final (ctx->hmac, local_hmac); /* Compare locally computed HMAC with packet HMAC */ - if (memcmp (local_hmac, BPTR (buf), hmac_len)) + if (memcmp_constant_time (local_hmac, BPTR (buf), hmac_len)) CRYPT_ERROR ("packet HMAC authentication failed"); ASSERT (buf_advance (buf, hmac_len)); @@ -401,7 +419,7 @@ init_key_type (struct key_type *kt, const char *ciphername, CLEAR (*kt); if (ciphername && ciphername_defined) { - kt->cipher = cipher_kt_get (ciphername); + kt->cipher = cipher_kt_get (translate_cipher_name_from_openvpn(ciphername)); kt->cipher_length = cipher_kt_key_size (kt->cipher); if (keysize > 0 && keysize <= MAX_CIPHER_KEY_LENGTH) kt->cipher_length = keysize; |