From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steffen Klassert Subject: [PATCH 03/11] af_key: fix buffer overread in verify_address_len() Date: Thu, 11 Jan 2018 12:37:38 +0100 Message-ID: <20180111113746.28186-4-steffen.klassert@secunet.com> References: <20180111113746.28186-1-steffen.klassert@secunet.com> Mime-Version: 1.0 Content-Type: text/plain Cc: Herbert Xu , Steffen Klassert , To: David Miller Return-path: Received: from a.mx.secunet.com ([62.96.220.36]:50848 "EHLO a.mx.secunet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932884AbeAKLhv (ORCPT ); Thu, 11 Jan 2018 06:37:51 -0500 In-Reply-To: <20180111113746.28186-1-steffen.klassert@secunet.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Eric Biggers If a message sent to a PF_KEY socket ended with one of the extensions that takes a 'struct sadb_address' but there were not enough bytes remaining in the message for the ->sa_family member of the 'struct sockaddr' which is supposed to follow, then verify_address_len() read past the end of the message, into uninitialized memory. Fix it by returning -EINVAL in this case. This bug was found using syzkaller with KMSAN. Reproducer: #include #include #include int main() { int sock = socket(PF_KEY, SOCK_RAW, PF_KEY_V2); char buf[24] = { 0 }; struct sadb_msg *msg = (void *)buf; struct sadb_address *addr = (void *)(msg + 1); msg->sadb_msg_version = PF_KEY_V2; msg->sadb_msg_type = SADB_DELETE; msg->sadb_msg_len = 3; addr->sadb_address_len = 1; addr->sadb_address_exttype = SADB_EXT_ADDRESS_SRC; write(sock, buf, 24); } Reported-by: Alexander Potapenko Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Signed-off-by: Steffen Klassert --- net/key/af_key.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/key/af_key.c b/net/key/af_key.c index 3dffb892d52c..596499cc8b2f 100644 --- a/net/key/af_key.c +++ b/net/key/af_key.c @@ -401,6 +401,11 @@ static int verify_address_len(const void *p) #endif int len; + if (sp->sadb_address_len < + DIV_ROUND_UP(sizeof(*sp) + offsetofend(typeof(*addr), sa_family), + sizeof(uint64_t))) + return -EINVAL; + switch (addr->sa_family) { case AF_INET: len = DIV_ROUND_UP(sizeof(*sp) + sizeof(*sin), sizeof(uint64_t)); -- 2.14.1