generic-library/openssl
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Option to disable padding extension.

Browse Source 
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
(cherry picked from commit 758415b2259fa45d3fe17d8e53ae1341b7b6e482)

Conflicts:

	ssl/t1_lib.c
This commit is contained in:
Dr. Stephen Henson 2014-06-01 16:08:18 +01:00
parent 08b172b975
commit 623a01df49
3 changed files with 29 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
doc/ssl/SSL_CTX_set_options.pod
View File

@ -112,6 +112,12 @@ vulnerability affecting CBC ciphers, which cannot be handled by some
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.

4
ssl/ssl.h
View File

@ -658,7 +658,7 @@ struct ssl_session_st
/* 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
@ -667,6 +667,8 @@ struct ssl_session_st
/* 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)

41
ssl/t1_lib.c
View File

@ -1468,36 +1468,35 @@ unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *p, unsigned cha
ret += outlen;
}
}
#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;