Debian CVE-2014-0160 patch

CVE-2014-0160.patch

From 96db9023b881d7cd9f379b0c154650d6c108e9a3 Mon Sep 17 00:00:00 2001
From: "Dr. Stephen Henson" <[email protected]>
Date: Sun, 6 Apr 2014 00:51:06 +0100
Subject: [PATCH] Add heartbeat extension bounds check.

A missing bounds check in the handling of the TLS heartbeat extension
can be used to reveal up to 64k of memory to a connected client or
server.

Thanks for Neel Mehta of Google Security for discovering this bug and to
Adam Langley <[email protected]> and Bodo Moeller <[email protected]> for
preparing the fix (CVE-2014-0160)
---
 CHANGES       |  9 +++++++++
 ssl/d1_both.c | 26 ++++++++++++++++++--------
 ssl/t1_lib.c  | 14 +++++++++-----
 3 files changed, 36 insertions(+), 13 deletions(-)

diff --git a/ssl/d1_both.c b/ssl/d1_both.c
index 7a5596a..2e8cf68 100644
--- a/ssl/d1_both.c
+++ b/ssl/d1_both.c
@@ -1459,26 +1459,36 @@ dtls1_process_heartbeat(SSL *s)
        unsigned int payload;
        unsigned int padding = 16; /* Use minimum padding */

-       /* Read type and payload length first */
-       hbtype = *p++;
-       n2s(p, payload);
-       pl = p;
-
        if (s->msg_callback)
                s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
                        &s->s3->rrec.data[0], s->s3->rrec.length,
                        s, s->msg_callback_arg);

+       /* Read type and payload length first */
+       if (1 + 2 + 16 > s->s3->rrec.length)
+               return 0; /* silently discard */
+       hbtype = *p++;
+       n2s(p, payload);
+       if (1 + 2 + payload + 16 > s->s3->rrec.length)
+               return 0; /* silently discard per RFC 6520 sec. 4 */
+       pl = p;
+
        if (hbtype == TLS1_HB_REQUEST)
                {
                unsigned char *buffer, *bp;
+               unsigned int write_length = 1 /* heartbeat type */ +
+                                           2 /* heartbeat length */ +
+                                           payload + padding;
                int r;

+               if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
+                       return 0;
+
                /* Allocate memory for the response, size is 1 byte
                 * message type, plus 2 bytes payload length, plus
                 * payload, plus padding
                 */
-               buffer = OPENSSL_malloc(1 + 2 + payload + padding);
+               buffer = OPENSSL_malloc(write_length);
                bp = buffer;

                /* Enter response type, length and copy payload */
@@ -1489,11 +1499,11 @@ dtls1_process_heartbeat(SSL *s)
                /* Random padding */
                RAND_pseudo_bytes(bp, padding);

-               r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, 3 + payload + padding);
+               r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, write_length);

                if (r >= 0 && s->msg_callback)
                        s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
-                               buffer, 3 + payload + padding,
+                               buffer, write_length,
                                s, s->msg_callback_arg);

                OPENSSL_free(buffer);
diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index b82fada..bddffd9 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -2588,16 +2588,20 @@ tls1_process_heartbeat(SSL *s)
        unsigned int payload;
        unsigned int padding = 16; /* Use minimum padding */

-       /* Read type and payload length first */
-       hbtype = *p++;
-       n2s(p, payload);
-       pl = p;
-
        if (s->msg_callback)
                s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
                        &s->s3->rrec.data[0], s->s3->rrec.length,
                        s, s->msg_callback_arg);

+       /* Read type and payload length first */
+       if (1 + 2 + 16 > s->s3->rrec.length)
+               return 0; /* silently discard */
+       hbtype = *p++;
+       n2s(p, payload);
+       if (1 + 2 + payload + 16 > s->s3->rrec.length)
+               return 0; /* silently discard per RFC 6520 sec. 4 */
+       pl = p;
+
        if (hbtype == TLS1_HB_REQUEST)
                {
                unsigned char *buffer, *bp;
--
1.9.1