New option SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS for disabling CBC
vulnerability workaround (included in SSL_OP_ALL).
PR: #90
diff --git a/ssl/s3_enc.c b/ssl/s3_enc.c
index 6dfef5c..72ac8b6 100644
--- a/ssl/s3_enc.c
+++ b/ssl/s3_enc.c
@@ -378,13 +378,18 @@
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 833f761..474e5a7 100644
--- a/ssl/ssl.h
+++ b/ssl/ssl.h
@@ -429,6 +429,7 @@
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 @@
#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 @@
* (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 @@
#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 @@
* 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 b80525f..ecd2d6c 100644
--- a/ssl/t1_enc.c
+++ b/ssl/t1_enc.c
@@ -483,13 +483,18 @@
{ int z; for (z=0; z<num; z++) printf("%02X%c",p1[z],((z+1)%16)?' ':'\n'); }
#endif
- /* 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 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:
