diff options
| author | Darrick J. Wong <darrick.wong@oracle.com> | 2016-12-05 12:32:50 +1100 |
|---|---|---|
| committer | Dave Chinner <david@fromorbit.com> | 2016-12-05 12:32:50 +1100 |
| commit | d2a047f31e86941fa896e0e3271536d50aba415e (patch) | |
| tree | 0ff8117d63fcf7b839a3facd7f2ca307efdb60c0 /fs/xfs/libxfs/xfs_ialloc.c | |
| parent | f7a136aee3c1c3f7daf87197b3b3c361744a2812 (diff) | |
xfs: forbid AG btrees with level == 0
There is no such thing as a zero-level AG btree since even a single-node
zero-records btree has one level. Btree cursor constructors read
cur_nlevels straight from disk and then access things like
cur_bufs[cur_nlevels - 1] which is /really/ bad if cur_nlevels is zero!
Therefore, strengthen the verifiers to prevent this possibility.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Diffstat (limited to 'fs/xfs/libxfs/xfs_ialloc.c')
| -rw-r--r-- | fs/xfs/libxfs/xfs_ialloc.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c index c482b9716347..d45c03779dae 100644 --- a/fs/xfs/libxfs/xfs_ialloc.c +++ b/fs/xfs/libxfs/xfs_ialloc.c @@ -2510,8 +2510,15 @@ xfs_agi_verify( if (!XFS_AGI_GOOD_VERSION(be32_to_cpu(agi->agi_versionnum))) return false; - if (be32_to_cpu(agi->agi_level) > XFS_BTREE_MAXLEVELS) + if (be32_to_cpu(agi->agi_level) < 1 || + be32_to_cpu(agi->agi_level) > XFS_BTREE_MAXLEVELS) return false; + + if (xfs_sb_version_hasfinobt(&mp->m_sb) && + (be32_to_cpu(agi->agi_free_level) < 1 || + be32_to_cpu(agi->agi_free_level) > XFS_BTREE_MAXLEVELS)) + return false; + /* * during growfs operations, the perag is not fully initialised, * so we can't use it for any useful checking. growfs ensures we can't |