[openssl-commits] [openssl] OpenSSL_1_0_2-stable update

[Matt Caswell]

The branch OpenSSL_1_0_2-stable has been updated
       via  2b31fcc0b5e7329e13806822a5709dbd51c5c8a4 (commit)
      from  b65b4c3481d9fc88056cd8373fd693d888ca064f (commit)


- Log -----------------------------------------------------------------
commit 2b31fcc0b5e7329e13806822a5709dbd51c5c8a4
Author: Matt Caswell <matt at openssl.org>
Date:   Thu Feb 26 11:56:00 2015 +0000

    Prevent handshake with unseeded PRNG
    
    Fix security issue where under certain conditions a client can complete a
    handshake with an unseeded PRNG. The conditions are:
    - Client is on a platform where the PRNG has not been seeded, and the
    user has not seeded manually
    - A protocol specific client method version has been used (i.e. not
    SSL_client_methodv23)
    - A ciphersuite is used that does not require additional random data
    from the PRNG beyond the initial ClientHello client random
    (e.g. PSK-RC4-SHA)
    
    If the handshake succeeds then the client random that has been used will
    have been generated from a PRNG with insufficient entropy and therefore
    the output may be predictable.
    
    For example using the following command with an unseeded openssl will
    succeed on an unpatched platform:
    
    openssl s_client -psk 1a2b3c4d -tls1_2 -cipher PSK-RC4-SHA
    
    CVE-2015-0285
    
    Reviewed-by: Richard Levitte <levitte at openssl.org>
    (cherry picked from commit e1b568dd2462f7cacf98f3d117936c34e2849a6b)

-----------------------------------------------------------------------

Summary of changes:
 ssl/s3_clnt.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/ssl/s3_clnt.c b/ssl/s3_clnt.c
index f186c3c..91053d5 100644
--- a/ssl/s3_clnt.c
+++ b/ssl/s3_clnt.c
@@ -717,8 +717,9 @@ int ssl3_client_hello(SSL *s)
         } else
             i = 1;
 
-        if (i)
-            ssl_fill_hello_random(s, 0, p, sizeof(s->s3->client_random));
+        if (i && ssl_fill_hello_random(s, 0, p,
+                                       sizeof(s->s3->client_random)) <= 0)
+            goto err;
 
         /* Do the message type and length last */
         d = p = ssl_handshake_start(s);