From 7e840163c06c7692b796a93e3fa85a93136adbb2 Mon Sep 17 00:00:00 2001 From: "Dr. Stephen Henson" 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 and Bodo Moeller for preparing the fix (CVE-2014-0160) (cherry picked from commit 96db9023b881d7cd9f379b0c154650d6c108e9a3) --- CHANGES | 9 +++++++++ ssl/d1_both.c | 26 ++++++++++++++++++-------- ssl/t1_lib.c | 14 +++++++++----- 3 files changed, 36 insertions(+), 13 deletions(-) diff --git a/CHANGES b/CHANGES index 400e065c5b..8f01731293 100644 --- a/CHANGES +++ b/CHANGES @@ -4,6 +4,15 @@ Changes between 1.0.1f and 1.0.2 [xx XXX xxxx] + *) 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 and Bodo Moeller for + preparing the fix (CVE-2014-0160) + [Adam Langley, Bodo Moeller] + *) Fix for the attack described in the paper "Recovering OpenSSL ECDSA Nonces Using the FLUSH+RELOAD Cache Side-channel Attack" by Yuval Yarom and Naomi Benger. Details can be obtained from: diff --git a/ssl/d1_both.c b/ssl/d1_both.c index f0c5962949..d8bcd58df2 100644 --- a/ssl/d1_both.c +++ b/ssl/d1_both.c @@ -1330,26 +1330,36 @@ 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 */ @@ -1360,11 +1370,11 @@ 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 c4f23c1022..80397b9c07 100644 --- a/ssl/t1_lib.c +++ b/ssl/t1_lib.c @@ -3801,16 +3801,20 @@ 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; -- 2.40.0