linux/fs/xfs/xfs_extfree_item.c
Dave Chinner 0612d11663 xfs: fix intent use-after-free on abort
When an intent is aborted during it's initial commit through
xfs_defer_trans_abort(), there is a use after free. The current
report is for a RUI  through this path in generic/388:

 Freed by task 6274:
  __kasan_slab_free+0x136/0x180
  kmem_cache_free+0xe7/0x4b0
  xfs_trans_free_items+0x198/0x2e0
  __xfs_trans_commit+0x27f/0xcc0
  xfs_trans_roll+0x17b/0x2a0
  xfs_defer_trans_roll+0x6ad/0xe60
  xfs_defer_finish+0x2a6/0x2140
  xfs_alloc_file_space+0x53a/0xf90
  xfs_file_fallocate+0x5c6/0xac0
  vfs_fallocate+0x2f5/0x930
  ioctl_preallocate+0x1dc/0x320
  do_vfs_ioctl+0xfe4/0x1690

The problem is that the RUI has two active references - one in the
current transaction, and another held by the defer_ops structure
that is passed to the RUD (intent done) so that both the intent and
the intent done structures are freed on commit of the intent done.

Hence during abort, we need to release the intent item, because the
defer_ops reference is released separately via ->abort_intent
callback. Fix all the intent code to do this correctly.

Signed-Off-By: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-04-02 20:08:27 -07:00

559 lines
15 KiB
C

/*
* Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "xfs.h"
#include "xfs_fs.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_trans.h"
#include "xfs_trans_priv.h"
#include "xfs_buf_item.h"
#include "xfs_extfree_item.h"
#include "xfs_log.h"
#include "xfs_btree.h"
#include "xfs_rmap.h"
kmem_zone_t *xfs_efi_zone;
kmem_zone_t *xfs_efd_zone;
static inline struct xfs_efi_log_item *EFI_ITEM(struct xfs_log_item *lip)
{
return container_of(lip, struct xfs_efi_log_item, efi_item);
}
void
xfs_efi_item_free(
struct xfs_efi_log_item *efip)
{
kmem_free(efip->efi_item.li_lv_shadow);
if (efip->efi_format.efi_nextents > XFS_EFI_MAX_FAST_EXTENTS)
kmem_free(efip);
else
kmem_zone_free(xfs_efi_zone, efip);
}
/*
* Freeing the efi requires that we remove it from the AIL if it has already
* been placed there. However, the EFI may not yet have been placed in the AIL
* when called by xfs_efi_release() from EFD processing due to the ordering of
* committed vs unpin operations in bulk insert operations. Hence the reference
* count to ensure only the last caller frees the EFI.
*/
void
xfs_efi_release(
struct xfs_efi_log_item *efip)
{
ASSERT(atomic_read(&efip->efi_refcount) > 0);
if (atomic_dec_and_test(&efip->efi_refcount)) {
xfs_trans_ail_remove(&efip->efi_item, SHUTDOWN_LOG_IO_ERROR);
xfs_efi_item_free(efip);
}
}
/*
* This returns the number of iovecs needed to log the given efi item.
* We only need 1 iovec for an efi item. It just logs the efi_log_format
* structure.
*/
static inline int
xfs_efi_item_sizeof(
struct xfs_efi_log_item *efip)
{
return sizeof(struct xfs_efi_log_format) +
(efip->efi_format.efi_nextents - 1) * sizeof(xfs_extent_t);
}
STATIC void
xfs_efi_item_size(
struct xfs_log_item *lip,
int *nvecs,
int *nbytes)
{
*nvecs += 1;
*nbytes += xfs_efi_item_sizeof(EFI_ITEM(lip));
}
/*
* This is called to fill in the vector of log iovecs for the
* given efi log item. We use only 1 iovec, and we point that
* at the efi_log_format structure embedded in the efi item.
* It is at this point that we assert that all of the extent
* slots in the efi item have been filled.
*/
STATIC void
xfs_efi_item_format(
struct xfs_log_item *lip,
struct xfs_log_vec *lv)
{
struct xfs_efi_log_item *efip = EFI_ITEM(lip);
struct xfs_log_iovec *vecp = NULL;
ASSERT(atomic_read(&efip->efi_next_extent) ==
efip->efi_format.efi_nextents);
efip->efi_format.efi_type = XFS_LI_EFI;
efip->efi_format.efi_size = 1;
xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_EFI_FORMAT,
&efip->efi_format,
xfs_efi_item_sizeof(efip));
}
/*
* Pinning has no meaning for an efi item, so just return.
*/
STATIC void
xfs_efi_item_pin(
struct xfs_log_item *lip)
{
}
/*
* The unpin operation is the last place an EFI is manipulated in the log. It is
* either inserted in the AIL or aborted in the event of a log I/O error. In
* either case, the EFI transaction has been successfully committed to make it
* this far. Therefore, we expect whoever committed the EFI to either construct
* and commit the EFD or drop the EFD's reference in the event of error. Simply
* drop the log's EFI reference now that the log is done with it.
*/
STATIC void
xfs_efi_item_unpin(
struct xfs_log_item *lip,
int remove)
{
struct xfs_efi_log_item *efip = EFI_ITEM(lip);
xfs_efi_release(efip);
}
/*
* Efi items have no locking or pushing. However, since EFIs are pulled from
* the AIL when their corresponding EFDs are committed to disk, their situation
* is very similar to being pinned. Return XFS_ITEM_PINNED so that the caller
* will eventually flush the log. This should help in getting the EFI out of
* the AIL.
*/
STATIC uint
xfs_efi_item_push(
struct xfs_log_item *lip,
struct list_head *buffer_list)
{
return XFS_ITEM_PINNED;
}
/*
* The EFI has been either committed or aborted if the transaction has been
* cancelled. If the transaction was cancelled, an EFD isn't going to be
* constructed and thus we free the EFI here directly.
*/
STATIC void
xfs_efi_item_unlock(
struct xfs_log_item *lip)
{
if (lip->li_flags & XFS_LI_ABORTED)
xfs_efi_release(EFI_ITEM(lip));
}
/*
* The EFI is logged only once and cannot be moved in the log, so simply return
* the lsn at which it's been logged.
*/
STATIC xfs_lsn_t
xfs_efi_item_committed(
struct xfs_log_item *lip,
xfs_lsn_t lsn)
{
return lsn;
}
/*
* The EFI dependency tracking op doesn't do squat. It can't because
* it doesn't know where the free extent is coming from. The dependency
* tracking has to be handled by the "enclosing" metadata object. For
* example, for inodes, the inode is locked throughout the extent freeing
* so the dependency should be recorded there.
*/
STATIC void
xfs_efi_item_committing(
struct xfs_log_item *lip,
xfs_lsn_t lsn)
{
}
/*
* This is the ops vector shared by all efi log items.
*/
static const struct xfs_item_ops xfs_efi_item_ops = {
.iop_size = xfs_efi_item_size,
.iop_format = xfs_efi_item_format,
.iop_pin = xfs_efi_item_pin,
.iop_unpin = xfs_efi_item_unpin,
.iop_unlock = xfs_efi_item_unlock,
.iop_committed = xfs_efi_item_committed,
.iop_push = xfs_efi_item_push,
.iop_committing = xfs_efi_item_committing
};
/*
* Allocate and initialize an efi item with the given number of extents.
*/
struct xfs_efi_log_item *
xfs_efi_init(
struct xfs_mount *mp,
uint nextents)
{
struct xfs_efi_log_item *efip;
uint size;
ASSERT(nextents > 0);
if (nextents > XFS_EFI_MAX_FAST_EXTENTS) {
size = (uint)(sizeof(xfs_efi_log_item_t) +
((nextents - 1) * sizeof(xfs_extent_t)));
efip = kmem_zalloc(size, KM_SLEEP);
} else {
efip = kmem_zone_zalloc(xfs_efi_zone, KM_SLEEP);
}
xfs_log_item_init(mp, &efip->efi_item, XFS_LI_EFI, &xfs_efi_item_ops);
efip->efi_format.efi_nextents = nextents;
efip->efi_format.efi_id = (uintptr_t)(void *)efip;
atomic_set(&efip->efi_next_extent, 0);
atomic_set(&efip->efi_refcount, 2);
return efip;
}
/*
* Copy an EFI format buffer from the given buf, and into the destination
* EFI format structure.
* The given buffer can be in 32 bit or 64 bit form (which has different padding),
* one of which will be the native format for this kernel.
* It will handle the conversion of formats if necessary.
*/
int
xfs_efi_copy_format(xfs_log_iovec_t *buf, xfs_efi_log_format_t *dst_efi_fmt)
{
xfs_efi_log_format_t *src_efi_fmt = buf->i_addr;
uint i;
uint len = sizeof(xfs_efi_log_format_t) +
(src_efi_fmt->efi_nextents - 1) * sizeof(xfs_extent_t);
uint len32 = sizeof(xfs_efi_log_format_32_t) +
(src_efi_fmt->efi_nextents - 1) * sizeof(xfs_extent_32_t);
uint len64 = sizeof(xfs_efi_log_format_64_t) +
(src_efi_fmt->efi_nextents - 1) * sizeof(xfs_extent_64_t);
if (buf->i_len == len) {
memcpy((char *)dst_efi_fmt, (char*)src_efi_fmt, len);
return 0;
} else if (buf->i_len == len32) {
xfs_efi_log_format_32_t *src_efi_fmt_32 = buf->i_addr;
dst_efi_fmt->efi_type = src_efi_fmt_32->efi_type;
dst_efi_fmt->efi_size = src_efi_fmt_32->efi_size;
dst_efi_fmt->efi_nextents = src_efi_fmt_32->efi_nextents;
dst_efi_fmt->efi_id = src_efi_fmt_32->efi_id;
for (i = 0; i < dst_efi_fmt->efi_nextents; i++) {
dst_efi_fmt->efi_extents[i].ext_start =
src_efi_fmt_32->efi_extents[i].ext_start;
dst_efi_fmt->efi_extents[i].ext_len =
src_efi_fmt_32->efi_extents[i].ext_len;
}
return 0;
} else if (buf->i_len == len64) {
xfs_efi_log_format_64_t *src_efi_fmt_64 = buf->i_addr;
dst_efi_fmt->efi_type = src_efi_fmt_64->efi_type;
dst_efi_fmt->efi_size = src_efi_fmt_64->efi_size;
dst_efi_fmt->efi_nextents = src_efi_fmt_64->efi_nextents;
dst_efi_fmt->efi_id = src_efi_fmt_64->efi_id;
for (i = 0; i < dst_efi_fmt->efi_nextents; i++) {
dst_efi_fmt->efi_extents[i].ext_start =
src_efi_fmt_64->efi_extents[i].ext_start;
dst_efi_fmt->efi_extents[i].ext_len =
src_efi_fmt_64->efi_extents[i].ext_len;
}
return 0;
}
return -EFSCORRUPTED;
}
static inline struct xfs_efd_log_item *EFD_ITEM(struct xfs_log_item *lip)
{
return container_of(lip, struct xfs_efd_log_item, efd_item);
}
STATIC void
xfs_efd_item_free(struct xfs_efd_log_item *efdp)
{
kmem_free(efdp->efd_item.li_lv_shadow);
if (efdp->efd_format.efd_nextents > XFS_EFD_MAX_FAST_EXTENTS)
kmem_free(efdp);
else
kmem_zone_free(xfs_efd_zone, efdp);
}
/*
* This returns the number of iovecs needed to log the given efd item.
* We only need 1 iovec for an efd item. It just logs the efd_log_format
* structure.
*/
static inline int
xfs_efd_item_sizeof(
struct xfs_efd_log_item *efdp)
{
return sizeof(xfs_efd_log_format_t) +
(efdp->efd_format.efd_nextents - 1) * sizeof(xfs_extent_t);
}
STATIC void
xfs_efd_item_size(
struct xfs_log_item *lip,
int *nvecs,
int *nbytes)
{
*nvecs += 1;
*nbytes += xfs_efd_item_sizeof(EFD_ITEM(lip));
}
/*
* This is called to fill in the vector of log iovecs for the
* given efd log item. We use only 1 iovec, and we point that
* at the efd_log_format structure embedded in the efd item.
* It is at this point that we assert that all of the extent
* slots in the efd item have been filled.
*/
STATIC void
xfs_efd_item_format(
struct xfs_log_item *lip,
struct xfs_log_vec *lv)
{
struct xfs_efd_log_item *efdp = EFD_ITEM(lip);
struct xfs_log_iovec *vecp = NULL;
ASSERT(efdp->efd_next_extent == efdp->efd_format.efd_nextents);
efdp->efd_format.efd_type = XFS_LI_EFD;
efdp->efd_format.efd_size = 1;
xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_EFD_FORMAT,
&efdp->efd_format,
xfs_efd_item_sizeof(efdp));
}
/*
* Pinning has no meaning for an efd item, so just return.
*/
STATIC void
xfs_efd_item_pin(
struct xfs_log_item *lip)
{
}
/*
* Since pinning has no meaning for an efd item, unpinning does
* not either.
*/
STATIC void
xfs_efd_item_unpin(
struct xfs_log_item *lip,
int remove)
{
}
/*
* There isn't much you can do to push on an efd item. It is simply stuck
* waiting for the log to be flushed to disk.
*/
STATIC uint
xfs_efd_item_push(
struct xfs_log_item *lip,
struct list_head *buffer_list)
{
return XFS_ITEM_PINNED;
}
/*
* The EFD is either committed or aborted if the transaction is cancelled. If
* the transaction is cancelled, drop our reference to the EFI and free the EFD.
*/
STATIC void
xfs_efd_item_unlock(
struct xfs_log_item *lip)
{
struct xfs_efd_log_item *efdp = EFD_ITEM(lip);
if (lip->li_flags & XFS_LI_ABORTED) {
xfs_efi_release(efdp->efd_efip);
xfs_efd_item_free(efdp);
}
}
/*
* When the efd item is committed to disk, all we need to do is delete our
* reference to our partner efi item and then free ourselves. Since we're
* freeing ourselves we must return -1 to keep the transaction code from further
* referencing this item.
*/
STATIC xfs_lsn_t
xfs_efd_item_committed(
struct xfs_log_item *lip,
xfs_lsn_t lsn)
{
struct xfs_efd_log_item *efdp = EFD_ITEM(lip);
/*
* Drop the EFI reference regardless of whether the EFD has been
* aborted. Once the EFD transaction is constructed, it is the sole
* responsibility of the EFD to release the EFI (even if the EFI is
* aborted due to log I/O error).
*/
xfs_efi_release(efdp->efd_efip);
xfs_efd_item_free(efdp);
return (xfs_lsn_t)-1;
}
/*
* The EFD dependency tracking op doesn't do squat. It can't because
* it doesn't know where the free extent is coming from. The dependency
* tracking has to be handled by the "enclosing" metadata object. For
* example, for inodes, the inode is locked throughout the extent freeing
* so the dependency should be recorded there.
*/
STATIC void
xfs_efd_item_committing(
struct xfs_log_item *lip,
xfs_lsn_t lsn)
{
}
/*
* This is the ops vector shared by all efd log items.
*/
static const struct xfs_item_ops xfs_efd_item_ops = {
.iop_size = xfs_efd_item_size,
.iop_format = xfs_efd_item_format,
.iop_pin = xfs_efd_item_pin,
.iop_unpin = xfs_efd_item_unpin,
.iop_unlock = xfs_efd_item_unlock,
.iop_committed = xfs_efd_item_committed,
.iop_push = xfs_efd_item_push,
.iop_committing = xfs_efd_item_committing
};
/*
* Allocate and initialize an efd item with the given number of extents.
*/
struct xfs_efd_log_item *
xfs_efd_init(
struct xfs_mount *mp,
struct xfs_efi_log_item *efip,
uint nextents)
{
struct xfs_efd_log_item *efdp;
uint size;
ASSERT(nextents > 0);
if (nextents > XFS_EFD_MAX_FAST_EXTENTS) {
size = (uint)(sizeof(xfs_efd_log_item_t) +
((nextents - 1) * sizeof(xfs_extent_t)));
efdp = kmem_zalloc(size, KM_SLEEP);
} else {
efdp = kmem_zone_zalloc(xfs_efd_zone, KM_SLEEP);
}
xfs_log_item_init(mp, &efdp->efd_item, XFS_LI_EFD, &xfs_efd_item_ops);
efdp->efd_efip = efip;
efdp->efd_format.efd_nextents = nextents;
efdp->efd_format.efd_efi_id = efip->efi_format.efi_id;
return efdp;
}
/*
* Process an extent free intent item that was recovered from
* the log. We need to free the extents that it describes.
*/
int
xfs_efi_recover(
struct xfs_mount *mp,
struct xfs_efi_log_item *efip)
{
struct xfs_efd_log_item *efdp;
struct xfs_trans *tp;
int i;
int error = 0;
xfs_extent_t *extp;
xfs_fsblock_t startblock_fsb;
struct xfs_owner_info oinfo;
ASSERT(!test_bit(XFS_EFI_RECOVERED, &efip->efi_flags));
/*
* First check the validity of the extents described by the
* EFI. If any are bad, then assume that all are bad and
* just toss the EFI.
*/
for (i = 0; i < efip->efi_format.efi_nextents; i++) {
extp = &efip->efi_format.efi_extents[i];
startblock_fsb = XFS_BB_TO_FSB(mp,
XFS_FSB_TO_DADDR(mp, extp->ext_start));
if (startblock_fsb == 0 ||
extp->ext_len == 0 ||
startblock_fsb >= mp->m_sb.sb_dblocks ||
extp->ext_len >= mp->m_sb.sb_agblocks) {
/*
* This will pull the EFI from the AIL and
* free the memory associated with it.
*/
set_bit(XFS_EFI_RECOVERED, &efip->efi_flags);
xfs_efi_release(efip);
return -EIO;
}
}
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
if (error)
return error;
efdp = xfs_trans_get_efd(tp, efip, efip->efi_format.efi_nextents);
xfs_rmap_any_owner_update(&oinfo);
for (i = 0; i < efip->efi_format.efi_nextents; i++) {
extp = &efip->efi_format.efi_extents[i];
error = xfs_trans_free_extent(tp, efdp, extp->ext_start,
extp->ext_len, &oinfo);
if (error)
goto abort_error;
}
set_bit(XFS_EFI_RECOVERED, &efip->efi_flags);
error = xfs_trans_commit(tp);
return error;
abort_error:
xfs_trans_cancel(tp);
return error;
}