diff options
Diffstat (limited to 'openssl/ssl/s23_srvr.c')
| -rw-r--r-- | openssl/ssl/s23_srvr.c | 30 |
1 files changed, 23 insertions, 7 deletions
diff --git a/openssl/ssl/s23_srvr.c b/openssl/ssl/s23_srvr.c index 487784901..2901a6bd0 100644 --- a/openssl/ssl/s23_srvr.c +++ b/openssl/ssl/s23_srvr.c @@ -348,23 +348,19 @@ int ssl23_get_client_hello(SSL *s) * Client Hello message, this would be difficult, and we'd have * to read more records to find out. * No known SSL 3.0 client fragments ClientHello like this, - * so we simply assume TLS 1.0 to avoid protocol version downgrade - * attacks. */ + * so we simply reject such connections to avoid + * protocol version downgrade attacks. */ if (p[3] == 0 && p[4] < 6) { -#if 0 SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,SSL_R_RECORD_TOO_SMALL); goto err; -#else - v[1] = TLS1_VERSION_MINOR; -#endif } /* if major version number > 3 set minor to a value * which will use the highest version 3 we support. * If TLS 2.0 ever appears we will need to revise * this.... */ - else if (p[9] > SSL3_VERSION_MAJOR) + if (p[9] > SSL3_VERSION_MAJOR) v[1]=0xff; else v[1]=p[10]; /* minor version according to client_version */ @@ -444,14 +440,34 @@ int ssl23_get_client_hello(SSL *s) v[0] = p[3]; /* == SSL3_VERSION_MAJOR */ v[1] = p[4]; + /* An SSLv3/TLSv1 backwards-compatible CLIENT-HELLO in an SSLv2 + * header is sent directly on the wire, not wrapped as a TLS + * record. It's format is: + * Byte Content + * 0-1 msg_length + * 2 msg_type + * 3-4 version + * 5-6 cipher_spec_length + * 7-8 session_id_length + * 9-10 challenge_length + * ... ... + */ n=((p[0]&0x7f)<<8)|p[1]; if (n > (1024*4)) { SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,SSL_R_RECORD_TOO_LARGE); goto err; } + if (n < 9) + { + SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,SSL_R_RECORD_LENGTH_MISMATCH); + goto err; + } j=ssl23_read_bytes(s,n+2); + /* We previously read 11 bytes, so if j > 0, we must have + * j == n+2 == s->packet_length. We have at least 11 valid + * packet bytes. */ if (j <= 0) return(j); ssl3_finish_mac(s, s->packet+2, s->packet_length-2); |