Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754647AbbKWNSv (ORCPT ); Mon, 23 Nov 2015 08:18:51 -0500 Received: from mx2.suse.de ([195.135.220.15]:59805 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754617AbbKWNMi (ORCPT ); Mon, 23 Nov 2015 08:12:38 -0500 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Ani Sinha , "David S . Miller" , Jiri Slaby Subject: [PATCH 3.12 51/72] net:socket: set msg_namelen to 0 if msg_name is passed as NULL in msghdr struct from userland. Date: Mon, 23 Nov 2015 14:12:12 +0100 Message-Id: X-Mailer: git-send-email 2.6.3 In-Reply-To: <09f041d02b9d5407d544d6fd5a9026072c44956f.1448283890.git.jslaby@suse.cz> References: <09f041d02b9d5407d544d6fd5a9026072c44956f.1448283890.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1512 Lines: 43 From: Ani Sinha 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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: Jiri Slaby --- net/socket.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/socket.c b/net/socket.c index 432b0bddd9e1..00634623573f 100644 --- a/net/socket.c +++ b/net/socket.c @@ -1970,6 +1970,9 @@ static int copy_msghdr_from_user(struct msghdr *kmsg, 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; -- 2.6.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/