diff options
Diffstat (limited to 'crypto/openssl/ssl/s3_srvr.c')
| -rw-r--r-- | crypto/openssl/ssl/s3_srvr.c | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/crypto/openssl/ssl/s3_srvr.c b/crypto/openssl/ssl/s3_srvr.c index d042329..258af84 100644 --- a/crypto/openssl/ssl/s3_srvr.c +++ b/crypto/openssl/ssl/s3_srvr.c @@ -1322,14 +1322,15 @@ static int ssl3_get_client_key_exchange(SSL *s) i=RSA_private_decrypt((int)n,p,p,rsa,RSA_PKCS1_PADDING); + al = -1; + if (i != SSL_MAX_MASTER_KEY_LENGTH) { al=SSL_AD_DECODE_ERROR; SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,SSL_R_BAD_RSA_DECRYPT); - goto f_err; } - if (!((p[0] == (s->client_version>>8)) && (p[1] == (s->client_version & 0xff)))) + if ((al == -1) && !((p[0] == (s->client_version>>8)) && (p[1] == (s->client_version & 0xff)))) { /* The premaster secret must contain the same version number as the * ClientHello to detect version rollback attacks (strangely, the @@ -1347,6 +1348,27 @@ static int ssl3_get_client_key_exchange(SSL *s) } } + if (al != -1) + { +#if 0 + goto f_err; +#else + /* Some decryption failure -- use random value instead as countermeasure + * against Bleichenbacher's attack on PKCS #1 v1.5 RSA padding + * (see RFC 2246, section 7.4.7.1). + * But note that due to length and protocol version checking, the + * attack is impractical anyway (see section 5 in D. Bleichenbacher: + * "Chosen Ciphertext Attacks Against Protocols Based on the RSA + * Encryption Standard PKCS #1", CRYPTO '98, LNCS 1462, pp. 1-12). + */ + ERR_clear_error(); + i = SSL_MAX_MASTER_KEY_LENGTH; + p[0] = s->client_version >> 8; + p[1] = s->client_version & 0xff; + RAND_pseudo_bytes(p+2, i-2); /* should be RAND_bytes, but we cannot work around a failure */ +#endif + } + s->session->master_key_length= s->method->ssl3_enc->generate_master_secret(s, s->session->master_key, |
