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| author | Darrick J. Wong | 2017-10-26 01:59:43 +0200 |
|---|---|---|
| committer | Darrick J. Wong | 2017-10-27 18:20:31 +0200 |
| commit | 8210f4dda2d7642cb7c882db55e53d899cced401 (patch) | |
| tree | bcc197df6ce3248726b89fe63fb0aa7ae204e1a8 /fs/xfs/xfs_attr_list.c | |
| parent | xfs: refactor extended attribute list operation (diff) | |
| download | kernel-qcow2-linux-8210f4dda2d7642cb7c882db55e53d899cced401.tar.gz kernel-qcow2-linux-8210f4dda2d7642cb7c882db55e53d899cced401.tar.xz kernel-qcow2-linux-8210f4dda2d7642cb7c882db55e53d899cced401.zip | |
xfs: abort dir/attr btree operation if btree is obviously weird
Abort an dir/attr btree operation if the attr btree has obvious problems
like loops back to the root or pointers don't point down the tree.
Found by fuzzing btree[0].before to zero in xfs/402, which livelocks on
the cycle in the attr btree.
Apply the same checks to xfs_da3_node_lookup_int.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Diffstat (limited to 'fs/xfs/xfs_attr_list.c')
| -rw-r--r-- | fs/xfs/xfs_attr_list.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/fs/xfs/xfs_attr_list.c b/fs/xfs/xfs_attr_list.c index 021ec5a0e070..a3603101e5f0 100644 --- a/fs/xfs/xfs_attr_list.c +++ b/fs/xfs/xfs_attr_list.c @@ -223,6 +223,7 @@ xfs_attr_node_list_lookup( struct xfs_buf *bp; int i; int error = 0; + unsigned int expected_level = 0; uint16_t magic; ASSERT(*pbp == NULL); @@ -246,6 +247,18 @@ xfs_attr_node_list_lookup( dp->d_ops->node_hdr_from_disk(&nodehdr, node); + /* Tree taller than we can handle; bail out! */ + if (nodehdr.level >= XFS_DA_NODE_MAXDEPTH) + goto out_corruptbuf; + + /* Check the level from the root node. */ + if (cursor->blkno == 0) + expected_level = nodehdr.level - 1; + else if (expected_level != nodehdr.level) + goto out_corruptbuf; + else + expected_level--; + btree = dp->d_ops->node_tree_p(node); for (i = 0; i < nodehdr.count; btree++, i++) { if (cursor->hashval <= be32_to_cpu(btree->hashval)) { @@ -259,8 +272,15 @@ xfs_attr_node_list_lookup( if (i == nodehdr.count) return 0; + + /* We can't point back to the root. */ + if (cursor->blkno == 0) + return -EFSCORRUPTED; } + if (expected_level != 0) + goto out_corruptbuf; + *pbp = bp; return 0; |