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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,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 CA6F6C28CF6 for ; Wed, 1 Aug 2018 17:31:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 848842083D for ; Wed, 1 Aug 2018 17:31:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 848842083D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org 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 S2407943AbeHATS1 (ORCPT ); Wed, 1 Aug 2018 15:18:27 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:52844 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389912AbeHATS0 (ORCPT ); Wed, 1 Aug 2018 15:18:26 -0400 Received: from localhost (D57E6652.static.ziggozakelijk.nl [213.126.102.82]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id ABEA2D4A; Wed, 1 Aug 2018 17:31:41 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Anatoly Trosinenko , Al Viro , Phillip Lougher , stable@kernel.org, Linus Torvalds Subject: [PATCH 4.9 137/144] squashfs: be more careful about metadata corruption Date: Wed, 1 Aug 2018 18:52:44 +0200 Message-Id: <20180801164958.802377555@linuxfoundation.org> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180801164949.023217860@linuxfoundation.org> References: <20180801164949.023217860@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Linus Torvalds commit 01cfb7937a9af2abb1136c7e89fbf3fd92952956 upstream. Anatoly Trosinenko reports that a corrupted squashfs image can cause a kernel oops. It turns out that squashfs can end up being confused about negative fragment lengths. The regular squashfs_read_data() does check for negative lengths, but squashfs_read_metadata() did not, and the fragment size code just blindly trusted the on-disk value. Fix both the fragment parsing and the metadata reading code. Reported-by: Anatoly Trosinenko Cc: Al Viro Cc: Phillip Lougher Cc: stable@kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/squashfs/cache.c | 3 +++ fs/squashfs/file.c | 8 ++++++-- fs/squashfs/fragment.c | 4 +--- fs/squashfs/squashfs_fs.h | 6 ++++++ 4 files changed, 16 insertions(+), 5 deletions(-) --- a/fs/squashfs/cache.c +++ b/fs/squashfs/cache.c @@ -350,6 +350,9 @@ int squashfs_read_metadata(struct super_ TRACE("Entered squashfs_read_metadata [%llx:%x]\n", *block, *offset); + if (unlikely(length < 0)) + return -EIO; + while (length) { entry = squashfs_cache_get(sb, msblk->block_cache, *block, 0); if (entry->error) { --- a/fs/squashfs/file.c +++ b/fs/squashfs/file.c @@ -194,7 +194,11 @@ static long long read_indexes(struct sup } for (i = 0; i < blocks; i++) { - int size = le32_to_cpu(blist[i]); + int size = squashfs_block_size(blist[i]); + if (size < 0) { + err = size; + goto failure; + } block += SQUASHFS_COMPRESSED_SIZE_BLOCK(size); } n -= blocks; @@ -367,7 +371,7 @@ static int read_blocklist(struct inode * sizeof(size)); if (res < 0) return res; - return le32_to_cpu(size); + return squashfs_block_size(size); } /* Copy data into page cache */ --- a/fs/squashfs/fragment.c +++ b/fs/squashfs/fragment.c @@ -61,9 +61,7 @@ int squashfs_frag_lookup(struct super_bl return size; *fragment_block = le64_to_cpu(fragment_entry.start_block); - size = le32_to_cpu(fragment_entry.size); - - return size; + return squashfs_block_size(fragment_entry.size); } --- a/fs/squashfs/squashfs_fs.h +++ b/fs/squashfs/squashfs_fs.h @@ -129,6 +129,12 @@ #define SQUASHFS_COMPRESSED_BLOCK(B) (!((B) & SQUASHFS_COMPRESSED_BIT_BLOCK)) +static inline int squashfs_block_size(__le32 raw) +{ + u32 size = le32_to_cpu(raw); + return (size >> 25) ? -EIO : size; +} + /* * Inode number ops. Inodes consist of a compressed block number, and an * uncompressed offset within that block