Option to disable padding extension.
Add TLS padding extension to SSL_OP_ALL so it is used with other
"bugs" options and can be turned off.
This replaces SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG which is an ancient
option referring to SSLv2 and SSLREF.
PR#3336
diff --git a/doc/ssl/SSL_CTX_set_options.pod b/doc/ssl/SSL_CTX_set_options.pod
index 4f990b2..e2548c3 100644
--- a/doc/ssl/SSL_CTX_set_options.pod
+++ b/doc/ssl/SSL_CTX_set_options.pod
@@ -112,6 +112,12 @@
broken SSL implementations. This option has no effect for connections
using other ciphers.
+=item SSL_OP_TLSEXT_PADDING
+
+Adds a padding extension to ensure the ClientHello size is never between
+256 and 511 bytes in length. This is needed as a workaround for some
+implementations.
+
=item SSL_OP_ALL
All of the above bug workarounds.
diff --git a/ssl/ssl.h b/ssl/ssl.h
index 7d0c7bb..950212f 100644
--- a/ssl/ssl.h
+++ b/ssl/ssl.h
@@ -662,7 +662,7 @@
/* Allow initial connection to servers that don't support RI */
#define SSL_OP_LEGACY_SERVER_CONNECT 0x00000004L
#define SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG 0x00000008L
-#define SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG 0x00000010L
+#define SSL_OP_TLSEXT_PADDING 0x00000010L
#define SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER 0x00000020L
#define SSL_OP_SAFARI_ECDHE_ECDSA_BUG 0x00000040L
#define SSL_OP_SSLEAY_080_CLIENT_DH_BUG 0x00000080L
@@ -671,6 +671,8 @@
/* Hasn't done anything since OpenSSL 0.9.7h, retained for compatibility */
#define SSL_OP_MSIE_SSLV2_RSA_PADDING 0x0
+/* Refers to ancient SSLREF and SSLv2, retained for compatibility */
+#define SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG 0x0
/* Disable SSL 3.0/TLS 1.0 CBC vulnerability workaround that was added
* in OpenSSL 0.9.6d. Usually (depending on the application protocol)
diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index 0ba37da..c4e27b9 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -1508,35 +1508,36 @@
s2n(TLSEXT_TYPE_encrypt_then_mac,ret);
s2n(0,ret);
#endif
-#ifdef TLSEXT_TYPE_padding
+
/* Add padding to workaround bugs in F5 terminators.
* See https://tools.ietf.org/html/draft-agl-tls-padding-03
*
* NB: because this code works out the length of all existing
* extensions it MUST always appear last.
*/
- {
- int hlen = ret - (unsigned char *)s->init_buf->data;
- /* The code in s23_clnt.c to build ClientHello messages includes the
- * 5-byte record header in the buffer, while the code in s3_clnt.c does
- * not. */
- if (s->state == SSL23_ST_CW_CLNT_HELLO_A)
- hlen -= 5;
- if (hlen > 0xff && hlen < 0x200)
+ if (s->options & SSL_OP_TLSEXT_PADDING)
{
- hlen = 0x200 - hlen;
- if (hlen >= 4)
- hlen -= 4;
- else
- hlen = 0;
+ int hlen = ret - (unsigned char *)s->init_buf->data;
+ /* The code in s23_clnt.c to build ClientHello messages
+ * includes the 5-byte record header in the buffer, while
+ * the code in s3_clnt.c does not.
+ */
+ if (s->state == SSL23_ST_CW_CLNT_HELLO_A)
+ hlen -= 5;
+ if (hlen > 0xff && hlen < 0x200)
+ {
+ hlen = 0x200 - hlen;
+ if (hlen >= 4)
+ hlen -= 4;
+ else
+ hlen = 0;
- s2n(TLSEXT_TYPE_padding, ret);
- s2n(hlen, ret);
- memset(ret, 0, hlen);
- ret += hlen;
+ s2n(TLSEXT_TYPE_padding, ret);
+ s2n(hlen, ret);
+ memset(ret, 0, hlen);
+ ret += hlen;
+ }
}
- }
-#endif
if ((extdatalen = ret-p-2) == 0)
return p;
