xfs: sanity check attr fork size

Recently we have quite a few kerneloops reports about dereferencing a NULL
if_data in the attribute fork.  From looking over the code this can only
happen if we pass a 0 size argument to xfs_iformat_local.  This implies some
sort of corruption and in fact the only mailinglist report about this from
earlier this year was after a powerfail presumably on a system with write
cache and without barriers.

Add a quick sanity check for the attr fork size in xfs_iformat to catch
these early and without an oops.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Christoph Hellwig 2009-01-19 02:04:16 +01:00 committed by Christoph Hellwig
parent 7884bc8617
commit 2809f76afc

View File

@ -424,6 +424,19 @@ xfs_iformat(
case XFS_DINODE_FMT_LOCAL:
atp = (xfs_attr_shortform_t *)XFS_DFORK_APTR(dip);
size = be16_to_cpu(atp->hdr.totsize);
if (unlikely(size < sizeof(struct xfs_attr_sf_hdr))) {
xfs_fs_repair_cmn_err(CE_WARN, ip->i_mount,
"corrupt inode %Lu "
"(bad attr fork size %Ld).",
(unsigned long long) ip->i_ino,
(long long) size);
XFS_CORRUPTION_ERROR("xfs_iformat(8)",
XFS_ERRLEVEL_LOW,
ip->i_mount, dip);
return XFS_ERROR(EFSCORRUPTED);
}
error = xfs_iformat_local(ip, dip, XFS_ATTR_FORK, size);
break;
case XFS_DINODE_FMT_EXTENTS: