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| author | Theodore Ts'o <tytso@mit.edu> | 2018-07-08 19:35:02 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-10-13 09:09:31 +0200 |
| commit | 5141d333432e3c1dc888feb6a4b93f4d39ad0e1c (patch) | |
| tree | ee5744c56e0c6ac91c431c7d97ebd2acac5260c0 | |
| parent | 6f6da33decb7d9de01447638ca737a846bf0181b (diff) | |
| download | linux-5141d333432e3c1dc888feb6a4b93f4d39ad0e1c.tar.gz linux-5141d333432e3c1dc888feb6a4b93f4d39ad0e1c.tar.bz2 linux-5141d333432e3c1dc888feb6a4b93f4d39ad0e1c.zip | |
ext4: fix false negatives *and* false positives in ext4_check_descriptors()
commit 44de022c4382541cebdd6de4465d1f4f465ff1dd upstream.
Ext4_check_descriptors() was getting called before s_gdb_count was
initialized. So for file systems w/o the meta_bg feature, allocation
bitmaps could overlap the block group descriptors and ext4 wouldn't
notice.
For file systems with the meta_bg feature enabled, there was a
fencepost error which would cause the ext4_check_descriptors() to
incorrectly believe that the block allocation bitmap overlaps with the
block group descriptor blocks, and it would reject the mount.
Fix both of these problems.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Hackmann <ghackmann@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/ext4/super.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 2dd4abc61c80..ad620f43a304 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2064,7 +2064,7 @@ static int ext4_check_descriptors(struct super_block *sb, struct ext4_sb_info *sbi = EXT4_SB(sb); ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block); ext4_fsblk_t last_block; - ext4_fsblk_t last_bg_block = sb_block + ext4_bg_num_gdb(sb, 0) + 1; + ext4_fsblk_t last_bg_block = sb_block + ext4_bg_num_gdb(sb, 0); ext4_fsblk_t block_bitmap; ext4_fsblk_t inode_bitmap; ext4_fsblk_t inode_table; @@ -4018,12 +4018,12 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) goto failed_mount2; } } + sbi->s_gdb_count = db_count; if (!ext4_check_descriptors(sb, logical_sb_block, &first_not_zeroed)) { ext4_msg(sb, KERN_ERR, "group descriptors corrupted!"); goto failed_mount2; } - sbi->s_gdb_count = db_count; get_random_bytes(&sbi->s_next_generation, sizeof(u32)); spin_lock_init(&sbi->s_next_gen_lock); |