Commit 0ddc5154 authored by Anant Thazhemadam's avatar Anant Thazhemadam Committed by Andreas Gruenbacher

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: default avatarAndrew Price <anprice@redhat.com>
Signed-off-by: default avatarAnant Thazhemadam <anant.thazhemadam@gmail.com>
[Minor code reordering.]
Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
parent c2a04b02
...@@ -169,15 +169,19 @@ static int gfs2_check_sb(struct gfs2_sbd *sdp, int silent) ...@@ -169,15 +169,19 @@ static int gfs2_check_sb(struct gfs2_sbd *sdp, int silent)
return -EINVAL; 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) {
if (sb->sb_fs_format == GFS2_FORMAT_FS && fs_warn(sdp, "Unknown on-disk format, unable to mount\n");
sb->sb_multihost_format == GFS2_FORMAT_MULTI) return -EINVAL;
return 0; }
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) static void end_bio_io_page(struct bio *bio)
......
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