From: Theodore Ts'o Subject: [PATCH 7/7] libext2fs: enforce the block group descriptor size in ext2fs_open() Date: Mon, 30 Jul 2012 17:47:42 -0400 Message-ID: <1343684862-13181-7-git-send-email-tytso@mit.edu> References: <20120628024356.GB17989@thor.bakeyournoodle.com> <1343684862-13181-1-git-send-email-tytso@mit.edu> Cc: tony@bakeyournoodle.com, Theodore Ts'o To: Ext4 Developers List Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:42155 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754715Ab2G3Vzw (ORCPT ); Mon, 30 Jul 2012 17:55:52 -0400 In-Reply-To: <1343684862-13181-1-git-send-email-tytso@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: Since various parts of the library depend on the value of s_desc_size, check to make sure it is the correct, expected value based on the file system features. Signed-off-by: "Theodore Ts'o" --- lib/ext2fs/ext2_err.et.in | 3 +++ lib/ext2fs/openfs.c | 15 +++++++++++++++ 2 files changed, 18 insertions(+) diff --git a/lib/ext2fs/ext2_err.et.in b/lib/ext2fs/ext2_err.et.in index ccf1894..5987185 100644 --- a/lib/ext2fs/ext2_err.et.in +++ b/lib/ext2fs/ext2_err.et.in @@ -443,4 +443,7 @@ ec EXT2_ET_MMP_CHANGE_ABORT, ec EXT2_ET_MMP_OPEN_DIRECT, "MMP: open with O_DIRECT failed" +ec EXT2_ET_BAD_DESC_SIZE, + "Block group descriptor size incorrect" + end diff --git a/lib/ext2fs/openfs.c b/lib/ext2fs/openfs.c index 482e4ab..fbe9acd 100644 --- a/lib/ext2fs/openfs.c +++ b/lib/ext2fs/openfs.c @@ -263,6 +263,21 @@ errcode_t ext2fs_open2(const char *name, const char *io_options, retval = EXT2_ET_CORRUPT_SUPERBLOCK; goto cleanup; } + + /* Enforce the block group descriptor size */ + if (fs->super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT) { + if (fs->super->s_desc_size != EXT2_MIN_DESC_SIZE_64BIT) { + retval = EXT2_ET_BAD_DESC_SIZE; + goto cleanup; + } + } else { + if (fs->super->s_desc_size && + fs->super->s_desc_size != EXT2_MIN_DESC_SIZE) { + retval = EXT2_ET_BAD_DESC_SIZE; + goto cleanup; + } + } + fs->cluster_ratio_bits = fs->super->s_log_cluster_size - fs->super->s_log_block_size; if (EXT2_BLOCKS_PER_GROUP(fs->super) != -- 1.7.12.rc0.22.gcdd159b