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_alloc.c | |
| parent | f7a136aee3c1c3f7daf87197b3b3c361744a2812 (diff) | |
| download | lwn-d2a047f31e86941fa896e0e3271536d50aba415e.tar.gz lwn-d2a047f31e86941fa896e0e3271536d50aba415e.zip | |
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_alloc.c')
| -rw-r--r-- | fs/xfs/libxfs/xfs_alloc.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c index effb64cf714f..5050056a0b06 100644 --- a/fs/xfs/libxfs/xfs_alloc.c +++ b/fs/xfs/libxfs/xfs_alloc.c @@ -2455,12 +2455,15 @@ xfs_agf_verify( be32_to_cpu(agf->agf_flcount) <= XFS_AGFL_SIZE(mp))) return false; - if (be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNO]) > XFS_BTREE_MAXLEVELS || + if (be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNO]) < 1 || + be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNT]) < 1 || + be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNO]) > XFS_BTREE_MAXLEVELS || be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNT]) > XFS_BTREE_MAXLEVELS) return false; if (xfs_sb_version_hasrmapbt(&mp->m_sb) && - be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]) > XFS_BTREE_MAXLEVELS) + (be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]) < 1 || + be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]) > XFS_BTREE_MAXLEVELS)) return false; /* @@ -2477,7 +2480,8 @@ xfs_agf_verify( return false; if (xfs_sb_version_hasreflink(&mp->m_sb) && - be32_to_cpu(agf->agf_refcount_level) > XFS_BTREE_MAXLEVELS) + (be32_to_cpu(agf->agf_refcount_level) < 1 || + be32_to_cpu(agf->agf_refcount_level) > XFS_BTREE_MAXLEVELS)) return false; return true;; |