From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Biggers Subject: [PATCH] af_key: fix buffer overread in parse_exthdrs() Date: Fri, 29 Dec 2017 18:15:23 -0600 Message-ID: <20171230001523.15761-1-ebiggers3@gmail.com> Cc: Alexander Potapenko , Dmitry Vyukov , Kostya Serebryany , syzkaller , Eric Biggers , stable@vger.kernel.org To: netdev@vger.kernel.org, Steffen Klassert , Herbert Xu , "David S . Miller" Return-path: Received: from mail-it0-f68.google.com ([209.85.214.68]:33988 "EHLO mail-it0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750855AbdL3ARD (ORCPT ); Fri, 29 Dec 2017 19:17:03 -0500 Sender: netdev-owner@vger.kernel.org List-ID: From: Eric Biggers If a message sent to a PF_KEY socket ended with an incomplete extension header (fewer than 4 bytes remaining), then parse_exthdrs() read past the end of the message, into uninitialized memory. Fix it by returning -EINVAL in this case. Reproducer: #include #include #include int main() { int sock = socket(PF_KEY, SOCK_RAW, PF_KEY_V2); char buf[17] = { 0 }; struct sadb_msg *msg = (void *)buf; msg->sadb_msg_version = PF_KEY_V2; msg->sadb_msg_type = SADB_DELETE; msg->sadb_msg_len = 2; write(sock, buf, 17); } Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers --- net/key/af_key.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/key/af_key.c b/net/key/af_key.c index 596499cc8b2f..d40861a048fe 100644 --- a/net/key/af_key.c +++ b/net/key/af_key.c @@ -516,6 +516,9 @@ static int parse_exthdrs(struct sk_buff *skb, const struct sadb_msg *hdr, void * uint16_t ext_type; int ext_len; + if (len < sizeof(*ehdr)) + return -EINVAL; + ext_len = ehdr->sadb_ext_len; ext_len *= sizeof(uint64_t); ext_type = ehdr->sadb_ext_type; -- 2.15.1