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fix for CVE-2010-4180

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This commit is contained in:
Dr. Stephen Henson 2010-12-02 18:49:28 +00:00
parent 7258d33794
commit 7890b562bc
5 changed files with 15 additions and 12 deletions
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5
CHANGES
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@ -4,6 +4,11 @@
Changes between 0.9.8p and 0.9.8q [xx XXX xxxx]
*) Disable code workaround for ancient and obsolete Netscape browsers
and servers: an attacker can use it in a ciphersuite downgrade attack.
Thanks to Martin Rex for discovering this bug. CVE-2010-4180
[Steve Henson]
*) Fixed J-PAKE implementation error, originally discovered by
Sebastien Martini, further info and confirmation from Stefan
Arentz and Feng Hao. Note that this fix is a security fix. CVE-2010-4252

1
NEWS
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@ -7,6 +7,7 @@
Major changes between OpenSSL 0.9.8p and OpenSSL 0.9.8q:
o Fix for security issue CVE-2010-4180
o Fix for CVE-2010-4252
Major changes between OpenSSL 0.9.8o and OpenSSL 0.9.8p:

13
doc/ssl/SSL_CTX_set_options.pod
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@ -78,18 +78,7 @@ this breaks this server so 16 bytes is the way to go.
=item SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG
ssl3.netscape.com:443, first a connection is established with RC4-MD5.
If it is then resumed, we end up using DES-CBC3-SHA. It should be
RC4-MD5 according to 7.6.1.3, 'cipher_suite'.
Netscape-Enterprise/2.01 (https://merchant.netscape.com) has this bug.
It only really shows up when connecting via SSLv2/v3 then reconnecting
via SSLv3. The cipher list changes....
NEW INFORMATION. Try connecting with a cipher list of just
DES-CBC-SHA:RC4-MD5. For some weird reason, each new connection uses
RC4-MD5, but a re-connect tries to use DES-CBC-SHA. So netscape, when
doing a re-connect, always takes the first cipher in the cipher list.
As of OpenSSL 0.9.8q and 1.0.0c, this option has no effect.
=item SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG

3
ssl/s3_clnt.c
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@ -814,8 +814,11 @@ int ssl3_get_server_hello(SSL *s)
s->session->cipher_id = s->session->cipher->id;
if (s->hit && (s->session->cipher_id != c->id))
{
/* Workaround is now obsolete */
#if 0
if (!(s->options &
SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG))
#endif
{
al=SSL_AD_ILLEGAL_PARAMETER;
SSLerr(SSL_F_SSL3_GET_SERVER_HELLO,SSL_R_OLD_SESSION_CIPHER_NOT_RETURNED);

5
ssl/s3_srvr.c
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@ -927,6 +927,10 @@ int ssl3_get_client_hello(SSL *s)
break;
}
}
/* Disabled because it can be used in a ciphersuite downgrade
* attack: CVE-2010-4180.
*/
#if 0
if (j == 0 && (s->options & SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG) && (sk_SSL_CIPHER_num(ciphers) == 1))
{
/* Special case as client bug workaround: the previously used cipher may
@ -941,6 +945,7 @@ int ssl3_get_client_hello(SSL *s)
j = 1;
}
}
#endif
if (j == 0)
{
/* we need to have the cipher in the cipher