diff options
author | Anant Thazhemadam <anant.thazhemadam@gmail.com> | 2020-10-14 22:01:09 +0530 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-11-10 10:22:14 +0100 |
commit | 6b93e109c18719223bf1f27a0a0829d2d0c36cdf (patch) | |
tree | 0f6d3bb751292e64f6df80966d5a1deacc7d31b2 /fs/gfs2/ops_fstype.c | |
parent | 8665b1ccc3a35e4288b9bb909a71b38f93844077 (diff) |
gfs2: add validation checks for size of superblock
[ Upstream commit 0ddc5154b24c96f20e94d653b0a814438de6032b ]
In gfs2_check_sb(), no validation checks are performed with regards to
the size of the superblock.
syzkaller detected a slab-out-of-bounds bug that was primarily caused
because the block size for a superblock was set to zero.
A valid size for a superblock is a power of 2 between 512 and PAGE_SIZE.
Performing validation checks and ensuring that the size of the superblock
is valid fixes this bug.
Reported-by: syzbot+af90d47a37376844e731@syzkaller.appspotmail.com
Tested-by: syzbot+af90d47a37376844e731@syzkaller.appspotmail.com
Suggested-by: Andrew Price <anprice@redhat.com>
Signed-off-by: Anant Thazhemadam <anant.thazhemadam@gmail.com>
[Minor code reordering.]
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs/gfs2/ops_fstype.c')
-rw-r--r-- | fs/gfs2/ops_fstype.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c index b7b43d00cc6d..8ed2b1a71637 100644 --- a/fs/gfs2/ops_fstype.c +++ b/fs/gfs2/ops_fstype.c @@ -160,15 +160,19 @@ static int gfs2_check_sb(struct gfs2_sbd *sdp, int silent) return -EINVAL; } - /* If format numbers match exactly, we're done. */ - - if (sb->sb_fs_format == GFS2_FORMAT_FS && - sb->sb_multihost_format == GFS2_FORMAT_MULTI) - return 0; + if (sb->sb_fs_format != GFS2_FORMAT_FS || + sb->sb_multihost_format != GFS2_FORMAT_MULTI) { + fs_warn(sdp, "Unknown on-disk format, unable to mount\n"); + return -EINVAL; + } - fs_warn(sdp, "Unknown on-disk format, unable to mount\n"); + if (sb->sb_bsize < 512 || sb->sb_bsize > PAGE_SIZE || + (sb->sb_bsize & (sb->sb_bsize - 1))) { + pr_warn("Invalid superblock size\n"); + return -EINVAL; + } - return -EINVAL; + return 0; } static void end_bio_io_page(struct bio *bio) |