From c21506ba024adb6d5655a92d61c1d3824e5dedcf Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bodo=20M=C3=B6ller?= Date: Fri, 14 Jun 2002 12:21:11 +0000 Subject: New option SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS for disabling CBC vulnerability workaround (included in SSL_OP_ALL). PR: #90 --- ssl/s3_enc.c | 15 ++++++++++----- ssl/ssl.h | 25 +++++++++++++++++++------ ssl/t1_enc.c | 15 ++++++++++----- 3 files changed, 39 insertions(+), 16 deletions(-) (limited to 'ssl') diff --git a/ssl/s3_enc.c b/ssl/s3_enc.c index 6dfef5caaf..72ac8b6913 100644 --- a/ssl/s3_enc.c +++ b/ssl/s3_enc.c @@ -378,13 +378,18 @@ int ssl3_setup_key_block(SSL *s) ret = ssl3_generate_key_block(s,p,num); - /* enable vulnerability countermeasure for CBC ciphers with - * known-IV problem (http://www.openssl.org/~bodo/tls-cbc.txt) */ - s->s3->need_empty_fragments = 1; + if (!(s->options & SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS)) + { + /* enable vulnerability countermeasure for CBC ciphers with + * known-IV problem (http://www.openssl.org/~bodo/tls-cbc.txt) + */ + s->s3->need_empty_fragments = 1; + #ifndef OPENSSL_NO_RC4 - if ((s->session->cipher != NULL) && ((s->session->cipher->algorithms & SSL_ENC_MASK) == SSL_RC4)) - s->s3->need_empty_fragments = 0; + if ((s->session->cipher != NULL) && ((s->session->cipher->algorithms & SSL_ENC_MASK) == SSL_RC4)) + s->s3->need_empty_fragments = 0; #endif + } return ret; diff --git a/ssl/ssl.h b/ssl/ssl.h index 833f761690..474e5a76ef 100644 --- a/ssl/ssl.h +++ b/ssl/ssl.h @@ -429,6 +429,7 @@ typedef struct ssl_session_st struct ssl_session_st *prev,*next; } SSL_SESSION; + #define SSL_OP_MICROSOFT_SESS_ID_BUG 0x00000001L #define SSL_OP_NETSCAPE_CHALLENGE_BUG 0x00000002L #define SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG 0x00000008L @@ -439,6 +440,19 @@ typedef struct ssl_session_st #define SSL_OP_TLS_D5_BUG 0x00000100L #define SSL_OP_TLS_BLOCK_PADDING_BUG 0x00000200L +/* Disable SSL 3.0/TLS 1.0 CBC vulnerability workaround that was added + * in OpenSSL 0.9.6d. Usually (depending on the application protocol) + * the workaround is not needed. Unfortunately some broken SSL/TLS + * implementations cannot handle it at all, which is why we include + * it in SSL_OP_ALL. */ +#define SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS 0x00000800L /* added in 0.9.6e */ + +/* SSL_OP_ALL: various bug workarounds that should be rather harmless. + * This used to be 0x000FFFFFL before 0.9.7. */ +#define SSL_OP_ALL 0x00000FFFL + +/* As server, disallow session resumption on renegotiation */ +#define SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION 0x00010000L /* If set, always create a new key when using tmp_dh parameters */ #define SSL_OP_SINGLE_DH_USE 0x00100000L /* Set to always use the tmp_rsa key when doing RSA operations, @@ -452,8 +466,10 @@ typedef struct ssl_session_st * (version 3.1) was announced in the client hello. Normally this is * forbidden to prevent version rollback attacks. */ #define SSL_OP_TLS_ROLLBACK_BUG 0x00800000L -/* As server, disallow session resumption on renegotiation */ -#define SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION 0x01000000L + +#define SSL_OP_NO_SSLv2 0x01000000L +#define SSL_OP_NO_SSLv3 0x02000000L +#define SSL_OP_NO_TLSv1 0x04000000L /* The next flag deliberately changes the ciphertest, this is a check * for the PKCS#1 attack */ @@ -461,11 +477,7 @@ typedef struct ssl_session_st #define SSL_OP_PKCS1_CHECK_2 0x10000000L #define SSL_OP_NETSCAPE_CA_DN_BUG 0x20000000L #define SSL_OP_NETSCAPE_DEMO_CIPHER_CHANGE_BUG 0x40000000L -#define SSL_OP_ALL 0x000FFFFFL -#define SSL_OP_NO_SSLv2 0x01000000L -#define SSL_OP_NO_SSLv3 0x02000000L -#define SSL_OP_NO_TLSv1 0x04000000L /* Allow SSL_write(..., n) to return r with 0 < r < n (i.e. report success * when just a single record has been written): */ @@ -479,6 +491,7 @@ typedef struct ssl_session_st * is blocking: */ #define SSL_MODE_AUTO_RETRY 0x00000004L + /* Note: SSL[_CTX]_set_{options,mode} use |= op on the previous value, * they cannot be used to clear bits. */ diff --git a/ssl/t1_enc.c b/ssl/t1_enc.c index b80525f3ba..ecd2d6cbb5 100644 --- a/ssl/t1_enc.c +++ b/ssl/t1_enc.c @@ -483,13 +483,18 @@ printf("\nkey block\n"); { int z; for (z=0; zs3->need_empty_fragments = 1; + if (!(s->options & SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS)) + { + /* enable vulnerability countermeasure for CBC ciphers with + * known-IV problem (http://www.openssl.org/~bodo/tls-cbc.txt) + */ + s->s3->need_empty_fragments = 1; + #ifndef NO_RC4 - if ((s->session->cipher != NULL) && ((s->session->cipher->algorithms & SSL_ENC_MASK) == SSL_RC4)) - s->s3->need_empty_fragments = 0; + if ((s->session->cipher != NULL) && ((s->session->cipher->algorithms & SSL_ENC_MASK) == SSL_RC4)) + s->s3->need_empty_fragments = 0; #endif + } return(1); err: -- cgit v1.2.3