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| author | Anant Thazhemadam <anant.thazhemadam@gmail.com> | 2020-10-14 18:31:09 +0200 |
|---|---|---|
| committer | Andreas Gruenbacher <agruenba@redhat.com> | 2020-10-15 14:29:03 +0200 |
| commit | 0ddc5154b24c96f20e94d653b0a814438de6032b (patch) | |
| tree | b8cab8d0cfce3bfe02f8cf87304ef2a255ae6f20 /fs | |
| parent | gfs2: use-after-free in sysfs deregistration (diff) | |
| download | linux-0ddc5154b24c96f20e94d653b0a814438de6032b.tar.xz linux-0ddc5154b24c96f20e94d653b0a814438de6032b.zip | |
gfs2: add validation checks for size of superblock
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>
Diffstat (limited to 'fs')
| -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 5bd602a290f7..03c33fc03c05 100644 --- a/fs/gfs2/ops_fstype.c +++ b/fs/gfs2/ops_fstype.c @@ -169,15 +169,19 @@ 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) |