[PATCH] reiserfs: add check for invalid 1st journal block

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]


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().

Reported-and-tested-by: syzbot+0ba9909df31c6a36974d@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
 fs/reiserfs/journal.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
index 9edc8e2b154e..d58f24a08385 100644
--- a/fs/reiserfs/journal.c
+++ b/fs/reiserfs/journal.c
@@ -2758,6 +2758,19 @@ int journal_init(struct super_block *sb, const char *j_dev_name,
 		goto free_and_return;
+	/*
+	 * Sanity check to see is journal first block correct.
+	 * If journal first block is invalid it can cause
+	 * zeroing important superblock members.
+	 */
+		reiserfs_warning(sb, "journal-1393",
+			"journal 1st super block is invalid: 1st reserved block %d, but actual 1st block is %d",
+		goto free_and_return;
+	}
 	if (journal_init_dev(sb, journal, j_dev_name) != 0) {
 		reiserfs_warning(sb, "sh-462",
 				 "unable to initialize journal device");

[Index of Archives]     [Linux File System Development]     [Linux BTRFS]     [Linux NFS]     [Linux Filesystems]     [Ext4 Filesystem]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite Forum]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Device Mapper]     [Linux Resources]

  Powered by Linux