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xfs: validate inode fork size against fork format

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xfs_repair catches fork size/format mismatches, but the in-kernel
verifier doesn't, leading to null pointer failures when attempting
to perform operations on the fork. This can occur in the
xfs_dir_is_empty() where the in-memory fork format does not match
the size and so the fork data pointer is accessed incorrectly.

Note: this causes new failures in xfs/348 which is testing mode vs
ftype mismatches. We now detect a regular file that has been changed
to a directory or symlink mode as being corrupt because the data
fork is for a symlink or directory should be in local form when
there are only 3 bytes of data in the data fork. Hence the inode
verify for the regular file now fires w/ -EFSCORRUPTED because
the inode fork format does not match the format the corrupted mode
says it should be in.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Dave Chinner 2022-05-04 12:13:53 +10:00 committed by Dave Chinner
parent dc04db2aa7
commit 1eb70f54c4
1 changed files with 27 additions and 10 deletions
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37
fs/xfs/libxfs/xfs_inode_buf.c
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@ -357,21 +357,38 @@ xfs_dinode_verify_fork(
{
xfs_extnum_t di_nextents;
xfs_extnum_t max_extents;
mode_t mode = be16_to_cpu(dip->di_mode);
uint32_t fork_size = XFS_DFORK_SIZE(dip, mp, whichfork);
uint32_t fork_format = XFS_DFORK_FORMAT(dip, whichfork);
di_nextents = xfs_dfork_nextents(dip, whichfork);
switch (XFS_DFORK_FORMAT(dip, whichfork)) {
case XFS_DINODE_FMT_LOCAL:
/*
* no local regular files yet
*/
if (whichfork == XFS_DATA_FORK) {
if (S_ISREG(be16_to_cpu(dip->di_mode)))
return __this_address;
if (be64_to_cpu(dip->di_size) >
XFS_DFORK_SIZE(dip, mp, whichfork))
/*
* For fork types that can contain local data, check that the fork
* format matches the size of local data contained within the fork.
*
* For all types, check that when the size says the should be in extent
* or btree format, the inode isn't claiming it is in local format.
*/
if (whichfork == XFS_DATA_FORK) {
if (S_ISDIR(mode) || S_ISLNK(mode)) {
if (be64_to_cpu(dip->di_size) <= fork_size &&
fork_format != XFS_DINODE_FMT_LOCAL)
return __this_address;
}
if (be64_to_cpu(dip->di_size) > fork_size &&
fork_format == XFS_DINODE_FMT_LOCAL)
return __this_address;
}
switch (fork_format) {
case XFS_DINODE_FMT_LOCAL:
/*
* No local regular files yet.
*/
if (S_ISREG(mode) && whichfork == XFS_DATA_FORK)
return __this_address;
if (di_nextents)
return __this_address;
break;