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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 366F7C43610 for ; Sun, 11 Nov 2018 20:27:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 02B2020818 for ; Sun, 11 Nov 2018 20:27:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 02B2020818 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk 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 S1731717AbeKLGQ6 (ORCPT ); Mon, 12 Nov 2018 01:16:58 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:50790 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730594AbeKLFs0 (ORCPT ); Mon, 12 Nov 2018 00:48:26 -0500 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gLvsk-0000oF-Jw; Sun, 11 Nov 2018 19:58:54 +0000 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gLvsY-0001nQ-Nl; Sun, 11 Nov 2018 19:58:42 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Phillip Lougher" , "Anatoly Trosinenko" , "Al Viro" , "Linus Torvalds" Date: Sun, 11 Nov 2018 19:49:05 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 301/366] squashfs: be more careful about metadata corruption In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.61-rc1 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 Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings --- 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