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=-8.9 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 0208BC43387 for ; Sat, 15 Dec 2018 16:24:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CFB322171F for ; Sat, 15 Dec 2018 16:23:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730558AbeLOQX6 (ORCPT ); Sat, 15 Dec 2018 11:23:58 -0500 Received: from lilium.sigma-star.at ([109.75.188.150]:47270 "EHLO lilium.sigma-star.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730500AbeLOQX6 (ORCPT ); Sat, 15 Dec 2018 11:23:58 -0500 Received: from localhost (localhost [127.0.0.1]) by lilium.sigma-star.at (Postfix) with ESMTP id 5E03B1801377B; Sat, 15 Dec 2018 17:23:56 +0100 (CET) From: Richard Weinberger To: linux-mtd@lists.infradead.org Cc: linux-kernel@vger.kernel.org, dwmw2@infradead.org, Richard Weinberger , stable@vger.kernel.org Subject: [PATCH] jffs2: Fix integer underflow in jffs2_rtime_compress Date: Sat, 15 Dec 2018 17:23:50 +0100 Message-Id: <20181215162350.12489-1-richard@nod.at> X-Mailer: git-send-email 2.20.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The rtime compressor assumes that at least two bytes are compressed. If we try to compress just one byte, the loop condition will wrap around and an out-of-bounds write happens. Cc: Signed-off-by: Richard Weinberger --- fs/jffs2/compr_rtime.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/jffs2/compr_rtime.c b/fs/jffs2/compr_rtime.c index 406d9cc84ba8..cbf700001fc9 100644 --- a/fs/jffs2/compr_rtime.c +++ b/fs/jffs2/compr_rtime.c @@ -39,6 +39,9 @@ static int jffs2_rtime_compress(unsigned char *data_in, =20 memset(positions,0,sizeof(positions)); =20 + if (*dstlen < 2) + return -1; + while (pos < (*sourcelen) && outpos <=3D (*dstlen)-2) { int backpos, runlen=3D0; unsigned char value; --=20 2.20.0