xfs: sanity-check the unused space before trying to use it

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In xfs_dir2_data_use_free, we examine on-disk metadata and ASSERT if
it doesn't make sense.  Since a carefully crafted fuzzed image can cause
the kernel to crash after blowing a bunch of assertions, let's move
those checks into a validator function and rig everything up to return
EFSCORRUPTED to userspace.  Found by lastbit fuzzing ltail.bestcount via
xfs/391.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

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This commit is contained in:

Darrick J. Wong 2018-03-23 10:06:51 -07:00

parent a27ba2607e

commit 6915ef35c0

5 changed files with 111 additions and 49 deletions

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2

fs/xfs/libxfs/xfs_dir2.h

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fs/xfs/libxfs/xfs_dir2_block.c

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fs/xfs/libxfs/xfs_dir2_data.c

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fs/xfs/libxfs/xfs_dir2_leaf.c

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fs/xfs/libxfs/xfs_dir2_node.c

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