From b828d8c33867dd6479644c06500975570bfd525c Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 19 Jan 2009 02:04:16 +0100 Subject: [PATCH] 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 Reviewed-by: Dave Chinner --- fs/xfs/xfs_inode.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 5a5e035e5d38..323ecd76a12c 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -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: