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 05F0FC35247 for ; Mon, 3 Feb 2020 16:43:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CBA922086A for ; Mon, 3 Feb 2020 16:43:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580748202; bh=Hg6fJc2xvd+sSX10VFGbOcYzB3+hADcjF6TvMXYAPXw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=OZI6Lb0/cDKL4IWxIcO/USMwDHE6V7Gdb6znOSAiAqtrkxfGltELEmeYg+6+gLxqP WiGL30w6NyUNe0qUI1mEvq5QXlYhMkAjwgKYfLGL41sIFQAg1N+0ckYH/yixhFIg2I ia36R1nmfPD5OaYt24cwDbeZzH0NCRr3XQgo57Oo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730529AbgBCQdJ (ORCPT ); Mon, 3 Feb 2020 11:33:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:46854 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730505AbgBCQdA (ORCPT ); Mon, 3 Feb 2020 11:33:00 -0500 Received: from localhost (unknown [104.132.45.99]) (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 C8ECB2051A; Mon, 3 Feb 2020 16:32:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580747580; bh=Hg6fJc2xvd+sSX10VFGbOcYzB3+hADcjF6TvMXYAPXw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=boywSbMRHY7UcZsBJBLiJonZFiuyFwbJnt+NYY5HMVOi6nw5CYYinvCNU4yMMaD0X a35KC64wJF8hpzLZMd+WjkelLrFkenOWBGbOoeSWGxjjJY67TOrK2ACrk2RBYwQ6Ky GZehBpgvCea+9Wf9oZBVyeDRT0NhTgQZmADYfP7c= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+e64a13c5369a194d67df@syzkaller.appspotmail.com, Dan Carpenter , Vlastimil Babka , Michal Hocko , Lee Schermerhorn , Andrea Arcangeli , Hugh Dickins , Andrew Morton , Linus Torvalds Subject: [PATCH 4.19 13/70] mm/mempolicy.c: fix out of bounds write in mpol_parse_str() Date: Mon, 3 Feb 2020 16:19:25 +0000 Message-Id: <20200203161914.503169429@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200203161912.158976871@linuxfoundation.org> References: <20200203161912.158976871@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: Dan Carpenter commit c7a91bc7c2e17e0a9c8b9745a2cb118891218fd1 upstream. What we are trying to do is change the '=' character to a NUL terminator and then at the end of the function we restore it back to an '='. The problem is there are two error paths where we jump to the end of the function before we have replaced the '=' with NUL. We end up putting the '=' in the wrong place (possibly one element before the start of the buffer). Link: http://lkml.kernel.org/r/20200115055426.vdjwvry44nfug7yy@kili.mountain Reported-by: syzbot+e64a13c5369a194d67df@syzkaller.appspotmail.com Fixes: 095f1fc4ebf3 ("mempolicy: rework shmem mpol parsing and display") Signed-off-by: Dan Carpenter Acked-by: Vlastimil Babka Dmitry Vyukov Cc: Michal Hocko Cc: Dan Carpenter Cc: Lee Schermerhorn Cc: Andrea Arcangeli Cc: Hugh Dickins Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/mempolicy.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2808,6 +2808,9 @@ int mpol_parse_str(char *str, struct mem char *flags = strchr(str, '='); int err = 1; + if (flags) + *flags++ = '\0'; /* terminate mode string */ + if (nodelist) { /* NUL-terminate mode or flags string */ *nodelist++ = '\0'; @@ -2818,9 +2821,6 @@ int mpol_parse_str(char *str, struct mem } else nodes_clear(nodes); - if (flags) - *flags++ = '\0'; /* terminate mode string */ - for (mode = 0; mode < MPOL_MAX; mode++) { if (!strcmp(str, policy_modes[mode])) { break;