reiserfs: add check for invalid 1st journal block

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[ Upstream commit a149127be5 ]

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>

...

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Pavel Skripkin 2021-05-17 15:15:45 +03:00 • committed by Greg Kroah-Hartman

parent c5073100dc

commit 69a71b59b1

1 changed files with 14 additions and 0 deletions

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fs/reiserfs/journal.c

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