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dm thin metadata: check fail_io before using data_sm

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Must check pmd->fail_io before using pmd->data_sm since
pmd->data_sm may be destroyed by other processes.

       P1(kworker)                             P2(message)
do_worker
 process_prepared
  process_prepared_discard_passdown_pt2
   dm_pool_dec_data_range
                                    pool_message
                                     commit
                                      dm_pool_commit_metadata
                                        ↓
                                       // commit failed
                                      metadata_operation_failed
                                       abort_transaction
                                        dm_pool_abort_metadata
                                         __open_or_format_metadata
                                           ↓
                                          dm_sm_disk_open
                                            ↓
                                           // open failed
                                           // pmd->data_sm is NULL
    dm_sm_dec_blocks
      ↓
     // try to access pmd->data_sm --> UAF

As shown above, if dm_pool_commit_metadata() and
dm_pool_abort_metadata() fail in pool_message process, kworker may
trigger UAF.

Fixes: be500ed721 ("dm space maps: improve performance with inc/dec on ranges of blocks")
Cc: stable@vger.kernel.org
Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
This commit is contained in:
Li Lingfeng 2023-06-06 20:20:24 +08:00 committed by Mike Snitzer
parent 2760904d89
commit cb65b282c9
1 changed files with 12 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
drivers/md/dm-thin-metadata.c
View File

@ -1756,13 +1756,15 @@ int dm_thin_remove_range(struct dm_thin_device *td,
int dm_pool_block_is_shared(struct dm_pool_metadata *pmd, dm_block_t b, bool *result)
{
int r;
int r = -EINVAL;
uint32_t ref_count;
down_read(&pmd->root_lock);
r = dm_sm_get_count(pmd->data_sm, b, &ref_count);
if (!r)
*result = (ref_count > 1);
if (!pmd->fail_io) {
r = dm_sm_get_count(pmd->data_sm, b, &ref_count);
if (!r)
*result = (ref_count > 1);
}
up_read(&pmd->root_lock);
return r;
@ -1770,10 +1772,11 @@ int dm_pool_block_is_shared(struct dm_pool_metadata *pmd, dm_block_t b, bool *re
int dm_pool_inc_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_t e)
{
int r = 0;
int r = -EINVAL;
pmd_write_lock(pmd);
r = dm_sm_inc_blocks(pmd->data_sm, b, e);
if (!pmd->fail_io)
r = dm_sm_inc_blocks(pmd->data_sm, b, e);
pmd_write_unlock(pmd);
return r;
@ -1781,10 +1784,11 @@ int dm_pool_inc_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_
int dm_pool_dec_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_t e)
{
int r = 0;
int r = -EINVAL;
pmd_write_lock(pmd);
r = dm_sm_dec_blocks(pmd->data_sm, b, e);
if (!pmd->fail_io)
r = dm_sm_dec_blocks(pmd->data_sm, b, e);
pmd_write_unlock(pmd);
return r;