linux/fs/xfs/xfs_attr_inactive.c
Darrick J. Wong c78c2d0903 xfs: don't leak memory when attr fork loading fails
I observed the following evidence of a memory leak while running xfs/399
from the xfs fsck test suite (edited for brevity):

XFS (sde): Metadata corruption detected at xfs_attr_shortform_verify_struct.part.0+0x7b/0xb0 [xfs], inode 0x1172 attr fork
XFS: Assertion failed: ip->i_af.if_u1.if_data == NULL, file: fs/xfs/libxfs/xfs_inode_fork.c, line: 315
------------[ cut here ]------------
WARNING: CPU: 2 PID: 91635 at fs/xfs/xfs_message.c:104 assfail+0x46/0x4a [xfs]
CPU: 2 PID: 91635 Comm: xfs_scrub Tainted: G        W         5.19.0-rc7-xfsx #rc7 6e6475eb29fd9dda3181f81b7ca7ff961d277a40
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014
RIP: 0010:assfail+0x46/0x4a [xfs]
Call Trace:
 <TASK>
 xfs_ifork_zap_attr+0x7c/0xb0
 xfs_iformat_attr_fork+0x86/0x110
 xfs_inode_from_disk+0x41d/0x480
 xfs_iget+0x389/0xd70
 xfs_bulkstat_one_int+0x5b/0x540
 xfs_bulkstat_iwalk+0x1e/0x30
 xfs_iwalk_ag_recs+0xd1/0x160
 xfs_iwalk_run_callbacks+0xb9/0x180
 xfs_iwalk_ag+0x1d8/0x2e0
 xfs_iwalk+0x141/0x220
 xfs_bulkstat+0x105/0x180
 xfs_ioc_bulkstat.constprop.0.isra.0+0xc5/0x130
 xfs_file_ioctl+0xa5f/0xef0
 __x64_sys_ioctl+0x82/0xa0
 do_syscall_64+0x2b/0x80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

This newly-added assertion checks that there aren't any incore data
structures hanging off the incore fork when we're trying to reset its
contents.  From the call trace, it is evident that iget was trying to
construct an incore inode from the ondisk inode, but the attr fork
verifier failed and we were trying to undo all the memory allocations
that we had done earlier.

The three assertions in xfs_ifork_zap_attr check that the caller has
already called xfs_idestroy_fork, which clearly has not been done here.
As the zap function then zeroes the pointers, we've effectively leaked
the memory.

The shortest change would have been to insert an extra call to
xfs_idestroy_fork, but it makes more sense to bundle the _idestroy_fork
call into _zap_attr, since all other callsites call _idestroy_fork
immediately prior to calling _zap_attr.  IOWs, it eliminates one way to
fail.

Note: This change only applies cleanly to 2ed5b09b3e, since we just
reworked the attr fork lifetime.  However, I think this memory leak has
existed since 0f45a1b20c, since the chain xfs_iformat_attr_fork ->
xfs_iformat_local -> xfs_init_local_fork will allocate
ifp->if_u1.if_data, but if xfs_ifork_verify_local_attr fails,
xfs_iformat_attr_fork will free i_afp without freeing any of the stuff
hanging off i_afp.  The solution for older kernels I think is to add the
missing call to xfs_idestroy_fork just prior to calling kmem_cache_free.

Found by fuzzing a.sfattr.hdr.totsize = lastbit in xfs/399.

Fixes: 2ed5b09b3e ("xfs: make inode attribute forks a permanent part of struct xfs_inode")
Probably-Fixes: 0f45a1b20c ("xfs: improve local fork verification")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-07-20 16:40:39 -07:00

393 lines
9.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* Copyright (c) 2013 Red Hat, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_bit.h"
#include "xfs_mount.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_inode.h"
#include "xfs_attr.h"
#include "xfs_attr_remote.h"
#include "xfs_trans.h"
#include "xfs_bmap.h"
#include "xfs_attr_leaf.h"
#include "xfs_quota.h"
#include "xfs_dir2.h"
#include "xfs_error.h"
/*
* Invalidate any incore buffers associated with this remote attribute value
* extent. We never log remote attribute value buffers, which means that they
* won't be attached to a transaction and are therefore safe to mark stale.
* The actual bunmapi will be taken care of later.
*/
STATIC int
xfs_attr3_rmt_stale(
struct xfs_inode *dp,
xfs_dablk_t blkno,
int blkcnt)
{
struct xfs_bmbt_irec map;
int nmap;
int error;
/*
* Roll through the "value", invalidating the attribute value's
* blocks.
*/
while (blkcnt > 0) {
/*
* Try to remember where we decided to put the value.
*/
nmap = 1;
error = xfs_bmapi_read(dp, (xfs_fileoff_t)blkno, blkcnt,
&map, &nmap, XFS_BMAPI_ATTRFORK);
if (error)
return error;
if (XFS_IS_CORRUPT(dp->i_mount, nmap != 1))
return -EFSCORRUPTED;
/*
* Mark any incore buffers for the remote value as stale. We
* never log remote attr value buffers, so the buffer should be
* easy to kill.
*/
error = xfs_attr_rmtval_stale(dp, &map, 0);
if (error)
return error;
blkno += map.br_blockcount;
blkcnt -= map.br_blockcount;
}
return 0;
}
/*
* Invalidate all of the "remote" value regions pointed to by a particular
* leaf block.
* Note that we must release the lock on the buffer so that we are not
* caught holding something that the logging code wants to flush to disk.
*/
STATIC int
xfs_attr3_leaf_inactive(
struct xfs_trans **trans,
struct xfs_inode *dp,
struct xfs_buf *bp)
{
struct xfs_attr3_icleaf_hdr ichdr;
struct xfs_mount *mp = bp->b_mount;
struct xfs_attr_leafblock *leaf = bp->b_addr;
struct xfs_attr_leaf_entry *entry;
struct xfs_attr_leaf_name_remote *name_rmt;
int error = 0;
int i;
xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &ichdr, leaf);
/*
* Find the remote value extents for this leaf and invalidate their
* incore buffers.
*/
entry = xfs_attr3_leaf_entryp(leaf);
for (i = 0; i < ichdr.count; entry++, i++) {
int blkcnt;
if (!entry->nameidx || (entry->flags & XFS_ATTR_LOCAL))
continue;
name_rmt = xfs_attr3_leaf_name_remote(leaf, i);
if (!name_rmt->valueblk)
continue;
blkcnt = xfs_attr3_rmt_blocks(dp->i_mount,
be32_to_cpu(name_rmt->valuelen));
error = xfs_attr3_rmt_stale(dp,
be32_to_cpu(name_rmt->valueblk), blkcnt);
if (error)
goto err;
}
xfs_trans_brelse(*trans, bp);
err:
return error;
}
/*
* Recurse (gasp!) through the attribute nodes until we find leaves.
* We're doing a depth-first traversal in order to invalidate everything.
*/
STATIC int
xfs_attr3_node_inactive(
struct xfs_trans **trans,
struct xfs_inode *dp,
struct xfs_buf *bp,
int level)
{
struct xfs_mount *mp = dp->i_mount;
struct xfs_da_blkinfo *info;
xfs_dablk_t child_fsb;
xfs_daddr_t parent_blkno, child_blkno;
struct xfs_buf *child_bp;
struct xfs_da3_icnode_hdr ichdr;
int error, i;
/*
* Since this code is recursive (gasp!) we must protect ourselves.
*/
if (level > XFS_DA_NODE_MAXDEPTH) {
xfs_buf_mark_corrupt(bp);
xfs_trans_brelse(*trans, bp); /* no locks for later trans */
return -EFSCORRUPTED;
}
xfs_da3_node_hdr_from_disk(dp->i_mount, &ichdr, bp->b_addr);
parent_blkno = xfs_buf_daddr(bp);
if (!ichdr.count) {
xfs_trans_brelse(*trans, bp);
return 0;
}
child_fsb = be32_to_cpu(ichdr.btree[0].before);
xfs_trans_brelse(*trans, bp); /* no locks for later trans */
bp = NULL;
/*
* If this is the node level just above the leaves, simply loop
* over the leaves removing all of them. If this is higher up
* in the tree, recurse downward.
*/
for (i = 0; i < ichdr.count; i++) {
/*
* Read the subsidiary block to see what we have to work with.
* Don't do this in a transaction. This is a depth-first
* traversal of the tree so we may deal with many blocks
* before we come back to this one.
*/
error = xfs_da3_node_read(*trans, dp, child_fsb, &child_bp,
XFS_ATTR_FORK);
if (error)
return error;
/* save for re-read later */
child_blkno = xfs_buf_daddr(child_bp);
/*
* Invalidate the subtree, however we have to.
*/
info = child_bp->b_addr;
switch (info->magic) {
case cpu_to_be16(XFS_DA_NODE_MAGIC):
case cpu_to_be16(XFS_DA3_NODE_MAGIC):
error = xfs_attr3_node_inactive(trans, dp, child_bp,
level + 1);
break;
case cpu_to_be16(XFS_ATTR_LEAF_MAGIC):
case cpu_to_be16(XFS_ATTR3_LEAF_MAGIC):
error = xfs_attr3_leaf_inactive(trans, dp, child_bp);
break;
default:
xfs_buf_mark_corrupt(child_bp);
xfs_trans_brelse(*trans, child_bp);
error = -EFSCORRUPTED;
break;
}
if (error)
return error;
/*
* Remove the subsidiary block from the cache and from the log.
*/
error = xfs_trans_get_buf(*trans, mp->m_ddev_targp,
child_blkno,
XFS_FSB_TO_BB(mp, mp->m_attr_geo->fsbcount), 0,
&child_bp);
if (error)
return error;
xfs_trans_binval(*trans, child_bp);
child_bp = NULL;
/*
* If we're not done, re-read the parent to get the next
* child block number.
*/
if (i + 1 < ichdr.count) {
struct xfs_da3_icnode_hdr phdr;
error = xfs_da3_node_read_mapped(*trans, dp,
parent_blkno, &bp, XFS_ATTR_FORK);
if (error)
return error;
xfs_da3_node_hdr_from_disk(dp->i_mount, &phdr,
bp->b_addr);
child_fsb = be32_to_cpu(phdr.btree[i + 1].before);
xfs_trans_brelse(*trans, bp);
bp = NULL;
}
/*
* Atomically commit the whole invalidate stuff.
*/
error = xfs_trans_roll_inode(trans, dp);
if (error)
return error;
}
return 0;
}
/*
* Indiscriminately delete the entire attribute fork
*
* Recurse (gasp!) through the attribute nodes until we find leaves.
* We're doing a depth-first traversal in order to invalidate everything.
*/
static int
xfs_attr3_root_inactive(
struct xfs_trans **trans,
struct xfs_inode *dp)
{
struct xfs_mount *mp = dp->i_mount;
struct xfs_da_blkinfo *info;
struct xfs_buf *bp;
xfs_daddr_t blkno;
int error;
/*
* Read block 0 to see what we have to work with.
* We only get here if we have extents, since we remove
* the extents in reverse order the extent containing
* block 0 must still be there.
*/
error = xfs_da3_node_read(*trans, dp, 0, &bp, XFS_ATTR_FORK);
if (error)
return error;
blkno = xfs_buf_daddr(bp);
/*
* Invalidate the tree, even if the "tree" is only a single leaf block.
* This is a depth-first traversal!
*/
info = bp->b_addr;
switch (info->magic) {
case cpu_to_be16(XFS_DA_NODE_MAGIC):
case cpu_to_be16(XFS_DA3_NODE_MAGIC):
error = xfs_attr3_node_inactive(trans, dp, bp, 1);
break;
case cpu_to_be16(XFS_ATTR_LEAF_MAGIC):
case cpu_to_be16(XFS_ATTR3_LEAF_MAGIC):
error = xfs_attr3_leaf_inactive(trans, dp, bp);
break;
default:
error = -EFSCORRUPTED;
xfs_buf_mark_corrupt(bp);
xfs_trans_brelse(*trans, bp);
break;
}
if (error)
return error;
/*
* Invalidate the incore copy of the root block.
*/
error = xfs_trans_get_buf(*trans, mp->m_ddev_targp, blkno,
XFS_FSB_TO_BB(mp, mp->m_attr_geo->fsbcount), 0, &bp);
if (error)
return error;
error = bp->b_error;
if (error) {
xfs_trans_brelse(*trans, bp);
return error;
}
xfs_trans_binval(*trans, bp); /* remove from cache */
/*
* Commit the invalidate and start the next transaction.
*/
error = xfs_trans_roll_inode(trans, dp);
return error;
}
/*
* xfs_attr_inactive kills all traces of an attribute fork on an inode. It
* removes both the on-disk and in-memory inode fork. Note that this also has to
* handle the condition of inodes without attributes but with an attribute fork
* configured, so we can't use xfs_inode_hasattr() here.
*
* The in-memory attribute fork is removed even on error.
*/
int
xfs_attr_inactive(
struct xfs_inode *dp)
{
struct xfs_trans *trans;
struct xfs_mount *mp;
int lock_mode = XFS_ILOCK_SHARED;
int error = 0;
mp = dp->i_mount;
ASSERT(! XFS_NOT_DQATTACHED(mp, dp));
xfs_ilock(dp, lock_mode);
if (!xfs_inode_has_attr_fork(dp))
goto out_destroy_fork;
xfs_iunlock(dp, lock_mode);
lock_mode = 0;
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_attrinval, 0, 0, 0, &trans);
if (error)
goto out_destroy_fork;
lock_mode = XFS_ILOCK_EXCL;
xfs_ilock(dp, lock_mode);
if (!xfs_inode_has_attr_fork(dp))
goto out_cancel;
/*
* No need to make quota reservations here. We expect to release some
* blocks, not allocate, in the common case.
*/
xfs_trans_ijoin(trans, dp, 0);
/*
* Invalidate and truncate the attribute fork extents. Make sure the
* fork actually has xattr blocks as otherwise the invalidation has no
* blocks to read and returns an error. In this case, just do the fork
* removal below.
*/
if (dp->i_af.if_nextents > 0) {
error = xfs_attr3_root_inactive(&trans, dp);
if (error)
goto out_cancel;
error = xfs_itruncate_extents(&trans, dp, XFS_ATTR_FORK, 0);
if (error)
goto out_cancel;
}
/* Reset the attribute fork - this also destroys the in-core fork */
xfs_attr_fork_remove(dp, trans);
error = xfs_trans_commit(trans);
xfs_iunlock(dp, lock_mode);
return error;
out_cancel:
xfs_trans_cancel(trans);
out_destroy_fork:
/* kill the in-core attr fork before we drop the inode lock */
xfs_ifork_zap_attr(dp);
if (lock_mode)
xfs_iunlock(dp, lock_mode);
return error;
}