From 8718cb66c85e9b6344dee892edf5bb9a77e6c5c7 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Mon, 30 Jul 2012 17:40:15 -0400 Subject: [PATCH] libext2fs: enforce the block group descriptor size in ext2fs_open() 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 ccf1894a..59871853 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 482e4aba..fbe9acde 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) != -- 2.11.0