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Commit 1d8d5889 authored by Ye Bin's avatar Ye Bin Committed by Greg Kroah-Hartman
Browse files

dm thin metadata: Fix use-after-free in dm_bm_set_read_only 



commit 3a653b205f29b3f9827a01a0c88bfbcb0d169494 upstream.

The following error ocurred when testing disk online/offline:

[  301.798344] device-mapper: thin: 253:5: aborting current metadata transaction
[  301.848441] device-mapper: thin: 253:5: failed to abort metadata transaction
[  301.849206] Aborting journal on device dm-26-8.
[  301.850489] EXT4-fs error (device dm-26) in __ext4_new_inode:943: Journal has aborted
[  301.851095] EXT4-fs (dm-26): Delayed block allocation failed for inode 398742 at logical offset 181 with max blocks 19 with error 30
[  301.854476] BUG: KASAN: use-after-free in dm_bm_set_read_only+0x3a/0x40 [dm_persistent_data]

Reason is:

 metadata_operation_failed
    abort_transaction
        dm_pool_abort_metadata
	    __create_persistent_data_objects
	        r = __open_or_format_metadata
	        if (r) --> If failed will free pmd->bm but pmd->bm not set NULL
		    dm_block_manager_destroy(pmd->bm);
    set_pool_mode
	dm_pool_metadata_read_only(pool->pmd);
	dm_bm_set_read_only(pmd->bm);  --> use-after-free

Add checks to see if pmd->bm is NULL in dm_bm_set_read_only and
dm_bm_set_read_write functions.  If bm is NULL it means creating the
bm failed and so dm_bm_is_read_only must return true.

Signed-off-by: default avatarYe Bin <yebin10@huawei.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarxiejingfeng <xiejingfeng@linux.alibaba.com>
Signed-off-by: default avatarJeffle Xu <jefflexu@linux.alibaba.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 74421020

drivers/md/dm-thin-metadata.c

+1 −1
Original line number Diff line number Diff line
@@ -901,7 +901,7 @@ int dm_pool_metadata_close(struct dm_pool_metadata *pmd) 
		return -EBUSY;

	}



	if (!dm_bm_is_read_only(pmd->bm) && !pmd->fail_io) {

	if (!pmd->fail_io && !dm_bm_is_read_only(pmd->bm)) {

		r = __commit_transaction(pmd);

		if (r < 0)

			DMWARN("%s: __commit_transaction() failed, error = %d",

drivers/md/persistent-data/dm-block-manager.c

+8 −6
Original line number Diff line number Diff line
@@ -494,7 +494,7 @@ int dm_bm_write_lock(struct dm_block_manager *bm, 
	void *p;

	int r;



	if (bm->read_only)

	if (dm_bm_is_read_only(bm))

		return -EPERM;



	p = dm_bufio_read(bm->bufio, b, (struct dm_buffer **) result);
@@ -563,7 +563,7 @@ int dm_bm_write_lock_zero(struct dm_block_manager *bm, 
	struct buffer_aux *aux;

	void *p;



	if (bm->read_only)

	if (dm_bm_is_read_only(bm))

		return -EPERM;



	p = dm_bufio_new(bm->bufio, b, (struct dm_buffer **) result);
@@ -603,7 +603,7 @@ EXPORT_SYMBOL_GPL(dm_bm_unlock); 


int dm_bm_flush(struct dm_block_manager *bm)

{

	if (bm->read_only)

	if (dm_bm_is_read_only(bm))

		return -EPERM;



	return dm_bufio_write_dirty_buffers(bm->bufio);
@@ -617,18 +617,20 @@ void dm_bm_prefetch(struct dm_block_manager *bm, dm_block_t b) 


bool dm_bm_is_read_only(struct dm_block_manager *bm)

{

	return bm->read_only;

	return (bm ? bm->read_only : true);

}

EXPORT_SYMBOL_GPL(dm_bm_is_read_only);



void dm_bm_set_read_only(struct dm_block_manager *bm)

{

	if (bm)

		bm->read_only = true;

}

EXPORT_SYMBOL_GPL(dm_bm_set_read_only);



void dm_bm_set_read_write(struct dm_block_manager *bm)

{

	if (bm)

		bm->read_only = false;

}

EXPORT_SYMBOL_GPL(dm_bm_set_read_write);