From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754576AbbEECQV (ORCPT ); Mon, 4 May 2015 22:16:21 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:50855 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752066AbbEEBV5 (ORCPT ); Mon, 4 May 2015 21:21:57 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Ani Sinha" , "David S. Miller" Date: Tue, 05 May 2015 02:16:39 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 182/221] net:socket: set msg_namelen to 0 if msg_name is passed as NULL in msghdr struct from userland. In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.69-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Ani Sinha commit 6a2a2b3ae0759843b22c929881cc184b00cc63ff upstream. Linux manpage for recvmsg and sendmsg calls does not explicitly mention setting msg_namelen to 0 when msg_name passed set as NULL. When developers don't set msg_namelen member in msghdr, it might contain garbage value which will fail the validation check and sendmsg and recvmsg calls from kernel will return EINVAL. This will break old binaries and any code for which there is no access to source code. To fix this, we set msg_namelen to 0 when msg_name is passed as NULL from userland. Signed-off-by: Ani Sinha Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/socket.c | 3 +++ 1 file changed, 3 insertions(+) --- a/net/socket.c +++ b/net/socket.c @@ -1885,6 +1885,9 @@ static int copy_msghdr_from_user(struct if (copy_from_user(kmsg, umsg, sizeof(struct msghdr))) return -EFAULT; + if (kmsg->msg_name == NULL) + kmsg->msg_namelen = 0; + if (kmsg->msg_namelen < 0) return -EINVAL;