diff options
| author | Pavel Skripkin <paskripkin@gmail.com> | 2021-05-17 15:15:45 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-07-20 16:22:37 +0200 |
| commit | 8ee7b3fa574f534620725178f3920d15987df430 (patch) | |
| tree | 109c8ac79f1c572f244327663391dce4b0dc24e2 /fs | |
| parent | 5c1d4ab7b025d911ef3da83a11ad6d0ac877c4be (diff) | |
reiserfs: add check for invalid 1st journal block
[ Upstream commit a149127be52fa7eaf5b3681a0317a2bbb772d5a9 ]
syzbot reported divide error in reiserfs.
The problem was in incorrect journal 1st block.
Syzbot's reproducer manualy generated wrong superblock
with incorrect 1st block. In journal_init() wasn't
any checks about this particular case.
For example, if 1st journal block is before superblock
1st block, it can cause zeroing important superblock members
in do_journal_end().
Link: https://lore.kernel.org/r/20210517121545.29645-1-paskripkin@gmail.com
Reported-by: syzbot+0ba9909df31c6a36974d@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/reiserfs/journal.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c index 00985f9db9f7..6a0fa0cdc1ed 100644 --- a/fs/reiserfs/journal.c +++ b/fs/reiserfs/journal.c @@ -2770,6 +2770,20 @@ int journal_init(struct super_block *sb, const char *j_dev_name, goto free_and_return; } + /* + * Sanity check to see if journal first block is correct. + * If journal first block is invalid it can cause + * zeroing important superblock members. + */ + if (!SB_ONDISK_JOURNAL_DEVICE(sb) && + SB_ONDISK_JOURNAL_1st_BLOCK(sb) < SB_JOURNAL_1st_RESERVED_BLOCK(sb)) { + reiserfs_warning(sb, "journal-1393", + "journal 1st super block is invalid: 1st reserved block %d, but actual 1st block is %d", + SB_JOURNAL_1st_RESERVED_BLOCK(sb), + SB_ONDISK_JOURNAL_1st_BLOCK(sb)); + goto free_and_return; + } + if (journal_init_dev(sb, journal, j_dev_name) != 0) { reiserfs_warning(sb, "sh-462", "unable to initialize journal device"); |