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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 6CCEBC2BBFD for ; Sat, 11 Apr 2020 12:12:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 40C93214D8 for ; Sat, 11 Apr 2020 12:12:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586607123; bh=pt0sCxf/SfWbDygnN5dOYqPQK+jJWPkkZA75lgKelHc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=sJMItrSxffGi0hoDNgk2r63KzselfaA3U/6VB487BngPlq7kO+Vr+3wjVJdsBKs1h NblIntLy9lNkhA8S2S8lNDPeuxouLD0WFav3UwaX3W/OZDRhLI63btpUITjApv6qRG bJIA49NNNdcbjF7gTfkDziHiV8EP9MlCnMO9URpg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727116AbgDKMMB (ORCPT ); Sat, 11 Apr 2020 08:12:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:44244 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727092AbgDKML5 (ORCPT ); Sat, 11 Apr 2020 08:11:57 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7171F21655; Sat, 11 Apr 2020 12:11:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586607116; bh=pt0sCxf/SfWbDygnN5dOYqPQK+jJWPkkZA75lgKelHc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qudoRYK31zdb9R9/zoH8vYmyLu5J4Qe4ZxzF38we2FkIYsYSEq5tMkLkq36/i4O3D V8bAm+KNqM0UMapZ+nSAqHKfWzERFGj57ASiqlceqDTGKpC2jY1xXiWIjm/pJ/RYuT eh+4uZZB6Hb0P4PNx7g8zypxPiiU0Mbyr5Upo408= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Entropy Moe <3ntr0py1337@gmail.com>, syzbot+b055b1a6b2b958707a21@syzkaller.appspotmail.com, Randy Dunlap , Andrew Morton , Lee Schermerhorn , Linus Torvalds , Guenter Roeck Subject: [PATCH 4.9 14/32] mm: mempolicy: require at least one nodeid for MPOL_PREFERRED Date: Sat, 11 Apr 2020 14:08:53 +0200 Message-Id: <20200411115420.163650460@linuxfoundation.org> X-Mailer: git-send-email 2.26.0 In-Reply-To: <20200411115418.455500023@linuxfoundation.org> References: <20200411115418.455500023@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Randy Dunlap commit aa9f7d5172fac9bf1f09e678c35e287a40a7b7dd upstream. Using an empty (malformed) nodelist that is not caught during mount option parsing leads to a stack-out-of-bounds access. The option string that was used was: "mpol=prefer:,". However, MPOL_PREFERRED requires a single node number, which is not being provided here. Add a check that 'nodes' is not empty after parsing for MPOL_PREFERRED's nodeid. Fixes: 095f1fc4ebf3 ("mempolicy: rework shmem mpol parsing and display") Reported-by: Entropy Moe <3ntr0py1337@gmail.com> Reported-by: syzbot+b055b1a6b2b958707a21@syzkaller.appspotmail.com Signed-off-by: Randy Dunlap Signed-off-by: Andrew Morton Tested-by: syzbot+b055b1a6b2b958707a21@syzkaller.appspotmail.com Cc: Lee Schermerhorn Link: http://lkml.kernel.org/r/89526377-7eb6-b662-e1d8-4430928abde9@infradead.org Signed-off-by: Linus Torvalds Cc: Guenter Roeck Signed-off-by: Greg Kroah-Hartman --- mm/mempolicy.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2768,7 +2768,9 @@ int mpol_parse_str(char *str, struct mem switch (mode) { case MPOL_PREFERRED: /* - * Insist on a nodelist of one node only + * Insist on a nodelist of one node only, although later + * we use first_node(nodes) to grab a single node, so here + * nodelist (or nodes) cannot be empty. */ if (nodelist) { char *rest = nodelist; @@ -2776,6 +2778,8 @@ int mpol_parse_str(char *str, struct mem rest++; if (*rest) goto out; + if (nodes_empty(nodes)) + goto out; } break; case MPOL_INTERLEAVE: