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| author | Brian Foster <bfoster@redhat.com> | 2019-03-17 15:21:49 -0700 |
|---|---|---|
| committer | Luis Chamberlain <mcgrof@kernel.org> | 2019-07-19 19:29:45 +0000 |
| commit | cc9cf389b5e276b48700f1e8b50427d7688ec989 (patch) | |
| tree | 7348dc89c5430e635b32757c255146aa2eef9a40 | |
| parent | a5959c0ce3038b7c646c302eb25dd23182e1c7b9 (diff) | |
| download | linux-stable-20190718-linux-xfs-4.19.y-v2.tar.gz | |
xfs: don't trip over uninitialized buffer on extent read of corrupted inode20190718-linux-xfs-4.19.y-v2
commit 6958d11f77d45db80f7e22a21a74d4d5f44dc667 upstream.
We've had rather rare reports of bmap btree block corruption where
the bmap root block has a level count of zero. The root cause of the
corruption is so far unknown. We do have verifier checks to detect
this form of on-disk corruption, but this doesn't cover a memory
corruption variant of the problem. The latter is a reasonable
possibility because the root block is part of the inode fork and can
reside in-core for some time before inode extents are read.
If this occurs, it leads to a system crash such as the following:
BUG: unable to handle kernel paging request at ffffffff00000221
PF error: [normal kernel read fault]
...
RIP: 0010:xfs_trans_brelse+0xf/0x200 [xfs]
...
Call Trace:
xfs_iread_extents+0x379/0x540 [xfs]
xfs_file_iomap_begin_delay+0x11a/0xb40 [xfs]
? xfs_attr_get+0xd1/0x120 [xfs]
? iomap_write_begin.constprop.40+0x2d0/0x2d0
xfs_file_iomap_begin+0x4c4/0x6d0 [xfs]
? __vfs_getxattr+0x53/0x70
? iomap_write_begin.constprop.40+0x2d0/0x2d0
iomap_apply+0x63/0x130
? iomap_write_begin.constprop.40+0x2d0/0x2d0
iomap_file_buffered_write+0x62/0x90
? iomap_write_begin.constprop.40+0x2d0/0x2d0
xfs_file_buffered_aio_write+0xe4/0x3b0 [xfs]
__vfs_write+0x150/0x1b0
vfs_write+0xba/0x1c0
ksys_pwrite64+0x64/0xa0
do_syscall_64+0x5a/0x1d0
entry_SYSCALL_64_after_hwframe+0x49/0xbe
The crash occurs because xfs_iread_extents() attempts to release an
uninitialized buffer pointer as the level == 0 value prevented the
buffer from ever being allocated or read. Change the level > 0
assert to an explicit error check in xfs_iread_extents() to avoid
crashing the kernel in the event of localized, in-core inode
corruption.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
[mcgrof: fixes kz#204223 ]
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
| -rw-r--r-- | fs/xfs/libxfs/xfs_bmap.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c index 3a496ffe6551c7..ab2465bc413af1 100644 --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -1178,7 +1178,10 @@ xfs_iread_extents( * Root level must use BMAP_BROOT_PTR_ADDR macro to get ptr out. */ level = be16_to_cpu(block->bb_level); - ASSERT(level > 0); + if (unlikely(level == 0)) { + XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, mp); + return -EFSCORRUPTED; + } pp = XFS_BMAP_BROOT_PTR_ADDR(mp, block, 1, ifp->if_broot_bytes); bno = be64_to_cpu(*pp); |