From patchwork Tue Apr 12 06:31:17 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 560475 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 68A72C4708C for ; Tue, 12 Apr 2022 07:33:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353599AbiDLHd6 (ORCPT ); Tue, 12 Apr 2022 03:33:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33674 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353711AbiDLHZw (ORCPT ); Tue, 12 Apr 2022 03:25:52 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A1791275F5; Tue, 12 Apr 2022 00:03:58 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 5B4B6B81B4E; Tue, 12 Apr 2022 07:03:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9B60DC385A1; Tue, 12 Apr 2022 07:03:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649747036; bh=r7zwxBmSBYLoVuMUOCzhurkmYQox+oscdpkyavZfQGg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KXyx+lqSZM7NibE6DSK3FpaEjfYFJV1d/9fBtn1X/Uih7Kduk73YojrlGYZgcVScA x0QxyN/G7txZCC8+1bjTrJJDPYJTUR+cNrEBzH/gq9bkDo/0MqZDu+jcc4iVn3s5Js 1CcJknzfK7ZkbQ00kbzI/eXVOnCJy1o2UH+F3hS0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+63d688f1d899c588fb71@syzkaller.appspotmail.com, Guo Xuenan , Nick Terrell , Gao Xiang , Yann Collet , Chengyang Fan , Andrew Morton , Linus Torvalds Subject: [PATCH 5.16 220/285] lz4: fix LZ4_decompress_safe_partial read out of bound Date: Tue, 12 Apr 2022 08:31:17 +0200 Message-Id: <20220412062950.006962534@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220412062943.670770901@linuxfoundation.org> References: <20220412062943.670770901@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Guo Xuenan commit eafc0a02391b7b36617b36c97c4b5d6832cf5e24 upstream. When partialDecoding, it is EOF if we've either filled the output buffer or can't proceed with reading an offset for following match. In some extreme corner cases when compressed data is suitably corrupted, UAF will occur. As reported by KASAN [1], LZ4_decompress_safe_partial may lead to read out of bound problem during decoding. lz4 upstream has fixed it [2] and this issue has been disscussed here [3] before. current decompression routine was ported from lz4 v1.8.3, bumping lib/lz4 to v1.9.+ is certainly a huge work to be done later, so, we'd better fix it first. [1] https://lore.kernel.org/all/000000000000830d1205cf7f0477@google.com/ [2] https://github.com/lz4/lz4/commit/c5d6f8a8be3927c0bec91bcc58667a6cfad244ad# [3] https://lore.kernel.org/all/CC666AE8-4CA4-4951-B6FB-A2EFDE3AC03B@fb.com/ Link: https://lkml.kernel.org/r/20211111105048.2006070-1-guoxuenan@huawei.com Reported-by: syzbot+63d688f1d899c588fb71@syzkaller.appspotmail.com Signed-off-by: Guo Xuenan Reviewed-by: Nick Terrell Acked-by: Gao Xiang Cc: Yann Collet Cc: Chengyang Fan Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- lib/lz4/lz4_decompress.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/lib/lz4/lz4_decompress.c +++ b/lib/lz4/lz4_decompress.c @@ -271,8 +271,12 @@ static FORCE_INLINE int LZ4_decompress_g ip += length; op += length; - /* Necessarily EOF, due to parsing restrictions */ - if (!partialDecoding || (cpy == oend)) + /* Necessarily EOF when !partialDecoding. + * When partialDecoding, it is EOF if we've either + * filled the output buffer or + * can't proceed with reading an offset for following match. + */ + if (!partialDecoding || (cpy == oend) || (ip >= (iend - 2))) break; } else { /* may overwrite up to WILDCOPYLENGTH beyond cpy */