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| author | Darrick J. Wong <darrick.wong@oracle.com> | 2018-02-26 22:43:17 -0600 |
|---|---|---|
| committer | Eric Sandeen <sandeen@redhat.com> | 2018-02-26 22:43:17 -0600 |
| commit | 493b46c4d9a1dbf636a1f3452c1ac36232ede6f4 (patch) | |
| tree | 9dde8a64d39617d2d408ae76cced5cf683c2b35d | |
| parent | fdef0e8b6a5e20f405526d5a2979fc2695f8d62d (diff) | |
| download | xfsprogs-dev-493b46c4d9a1dbf636a1f3452c1ac36232ede6f4.tar.gz | |
xfs: harden directory integrity checks some more
Source kernel commit: 46c59736d8090e602f960aeaf1c6b8292151bf38
If a malicious filesystem image contains a block+ format directory
wherein the directory inode's core.mode is set such that
S_ISDIR(core.mode) == 0, and if there are subdirectories of the
corrupted directory, an attempt to traverse up the directory tree will
crash the kernel in __xfs_dir3_data_check. Running the online scrub's
parent checks will tend to do this.
The crash occurs because the directory inode's d_ops get set to
xfs_dir[23]_nondir_ops (it's not a directory) but the parent pointer
scrubber's indiscriminate call to xfs_readdir proceeds past the ASSERT
if we have non fatal asserts configured.
Fix the null pointer dereference crash in __xfs_dir3_data_check by
looking for S_ISDIR or wrong d_ops; and teach the parent scrubber
to bail out if it is fed a non-directory "parent".
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
| -rw-r--r-- | libxfs/xfs_dir2_data.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/libxfs/xfs_dir2_data.c b/libxfs/xfs_dir2_data.c index 0ef5177821..1f46115f42 100644 --- a/libxfs/xfs_dir2_data.c +++ b/libxfs/xfs_dir2_data.c @@ -70,6 +70,14 @@ __xfs_dir3_data_check( */ ops = xfs_dir_get_ops(mp, dp); + /* + * If this isn't a directory, or we don't get handed the dir ops, + * something is seriously wrong. Bail out. + */ + if ((dp && !S_ISDIR(VFS_I(dp)->i_mode)) || + ops != xfs_dir_get_ops(mp, NULL)) + return __this_address; + hdr = bp->b_addr; p = (char *)ops->data_entry_p(hdr); |