diff options
| author | Richard Levitte <levitte@openssl.org> | 2001-06-05 09:08:26 +0400 |
|---|---|---|
| committer | Richard Levitte <levitte@openssl.org> | 2001-06-05 09:08:26 +0400 |
| commit | 4ae5099856741dd7cf365dbd2c1df45751dfbf4f (patch) | |
| tree | c218683fb5358552e9e1f9ca7a38f4a0045f3914 /ssl | |
| parent | 5c36f01000e38d11465259f81fc3c052d00d52e8 (diff) | |
Add changes from the 0.9.6-stable branch.
Diffstat (limited to 'ssl')
| -rw-r--r-- | ssl/s2_srvr.c | 3 | ||||
| -rw-r--r-- | ssl/s3_srvr.c | 26 |
2 files changed, 26 insertions, 3 deletions
diff --git a/ssl/s2_srvr.c b/ssl/s2_srvr.c index 1ed02540ae..2fa2f310a8 100644 --- a/ssl/s2_srvr.c +++ b/ssl/s2_srvr.c @@ -405,12 +405,13 @@ static int get_client_master_key(SSL *s) /* bad decrypt */ #if 1 /* If a bad decrypt, continue with protocol but with a - * dud master secret */ + * random master secret (Bleichenbacher attack) */ if ((i < 0) || ((!is_export && (i != EVP_CIPHER_key_length(c))) || (is_export && ((i != ek) || (s->s2->tmp.clear+i != EVP_CIPHER_key_length(c)))))) { + ERR_clear_error(); if (is_export) i=ek; else diff --git a/ssl/s3_srvr.c b/ssl/s3_srvr.c index d04232960e..258af84867 100644 --- a/ssl/s3_srvr.c +++ b/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, |