From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5ACE5C43382 for ; Tue, 25 Sep 2018 17:19:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1BC9F2086B for ; Tue, 25 Sep 2018 17:19:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1BC9F2086B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xmission.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728025AbeIYX2Y (ORCPT ); Tue, 25 Sep 2018 19:28:24 -0400 Received: from out02.mta.xmission.com ([166.70.13.232]:60785 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726400AbeIYX2X (ORCPT ); Tue, 25 Sep 2018 19:28:23 -0400 Received: from in01.mta.xmission.com ([166.70.13.51]) by out02.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.87) (envelope-from ) id 1g4r07-0000Xd-3w; Tue, 25 Sep 2018 11:19:55 -0600 Received: from [105.184.227.67] (helo=x220.Home) by in01.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_CBC_SHA256:128) (Exim 4.87) (envelope-from ) id 1g4r06-0001uD-0y; Tue, 25 Sep 2018 11:19:54 -0600 From: "Eric W. Biederman" To: linux-kernel@vger.kernel.org Cc: linux-api@vger.kernel.org, linux-arch@vger.kernel.org, Oleg Nesterov , Linus Torvalds , "Eric W. Biederman" Date: Tue, 25 Sep 2018 19:19:02 +0200 Message-Id: <20180925171906.19683-2-ebiederm@xmission.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <87h8idv6nw.fsf@xmission.com> References: <87h8idv6nw.fsf@xmission.com> X-XM-SPF: eid=1g4r06-0001uD-0y;;;mid=<20180925171906.19683-2-ebiederm@xmission.com>;;;hst=in01.mta.xmission.com;;;ip=105.184.227.67;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1+Vj4CgC0WrCxvJmB02LgyOu8MWo/KdEDs= X-SA-Exim-Connect-IP: 105.184.227.67 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [REVIEW][PATCH 2/6] signal: Fail sigqueueinfo if si_signo != sig X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The kernel needs to validate that the contents of struct siginfo make sense as siginfo is copied into the kernel, so that the proper union members can be put in the appropriate locations. The field si_signo is a fundamental part of that validation. As such changing the contents of si_signo after the validation make no sense and can result in nonsense values in the kernel. As such simply fail if someone is silly enough to set si_signo out of sync with the signal number passed to sigqueueinfo. I don't expect a problem as glibc's sigqueue implementation sets "si_signo = sig" and CRIU just returns to the kernel what the kernel gave to it. If there is some application that calls sigqueueinfo directly that has a problem with this added sanity check we can revisit this when we see what kind of crazy that application is doing. Signed-off-by: "Eric W. Biederman" --- kernel/signal.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/signal.c b/kernel/signal.c index 7b49c31d3fdb..e445b0a63faa 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -3306,7 +3306,8 @@ static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info) (task_pid_vnr(current) != pid)) return -EPERM; - info->si_signo = sig; + if (info->si_signo != sig) + return -EINVAL; /* POSIX.1b doesn't mention process groups. */ return kill_proc_info(sig, info, pid); @@ -3354,7 +3355,8 @@ static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info) (task_pid_vnr(current) != pid)) return -EPERM; - info->si_signo = sig; + if (info->si_signo != sig) + return -EINVAL; return do_send_specific(tgid, pid, sig, info); } -- 2.17.1