From 36bca8993f52be84f31c476449ca1527d62e16e1 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Mon, 30 Sep 2013 03:15:16 +0000 Subject: [PATCH] xfs: check magic numbers in dir3 leaf verifier first Calling xfs_dir3_leaf_hdr_from_disk() in a verifier before validating the magic numbers in the buffer results in ASSERT failures due to mismatching magic numbers when a corruption occurs. Seeing as the verifier is supposed to catch the corruption and pass it back to the caller, having the verifier assert fail on error defeats the purpose of detecting the errors in the first place. Check the magic numbers direct from the buffer before decoding the header. Signed-off-by: Dave Chinner Reviewed-by: Eric Sandeen Signed-off-by: Rich Johnston --- libxfs/xfs_dir2_leaf.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/libxfs/xfs_dir2_leaf.c b/libxfs/xfs_dir2_leaf.c index 7ec2f1975..c035c4dfb 100644 --- a/libxfs/xfs_dir2_leaf.c +++ b/libxfs/xfs_dir2_leaf.c @@ -161,6 +161,11 @@ xfs_dir3_leaf_check_int( return true; } +/* + * We verify the magic numbers before decoding the leaf header so that on debug + * kernels we don't get assertion failures in xfs_dir3_leaf_hdr_from_disk() due + * to incorrect magic numbers. + */ static bool xfs_dir3_leaf_verify( struct xfs_buf *bp, @@ -172,24 +177,25 @@ xfs_dir3_leaf_verify( ASSERT(magic == XFS_DIR2_LEAF1_MAGIC || magic == XFS_DIR2_LEAFN_MAGIC); - xfs_dir3_leaf_hdr_from_disk(&leafhdr, leaf); if (xfs_sb_version_hascrc(&mp->m_sb)) { struct xfs_dir3_leaf_hdr *leaf3 = bp->b_addr; + __uint16_t magic3; - if ((magic == XFS_DIR2_LEAF1_MAGIC && - leafhdr.magic != XFS_DIR3_LEAF1_MAGIC) || - (magic == XFS_DIR2_LEAFN_MAGIC && - leafhdr.magic != XFS_DIR3_LEAFN_MAGIC)) - return false; + magic3 = (magic == XFS_DIR2_LEAF1_MAGIC) ? XFS_DIR3_LEAF1_MAGIC + : XFS_DIR3_LEAFN_MAGIC; + if (leaf3->info.hdr.magic != cpu_to_be16(magic3)) + return false; if (!uuid_equal(&leaf3->info.uuid, &mp->m_sb.sb_uuid)) return false; if (be64_to_cpu(leaf3->info.blkno) != bp->b_bn) return false; } else { - if (leafhdr.magic != magic) + if (leaf->hdr.info.magic != cpu_to_be16(magic)) return false; } + + xfs_dir3_leaf_hdr_from_disk(&leafhdr, leaf); return xfs_dir3_leaf_check_int(mp, &leafhdr, leaf); } -- 2.47.2