From 3a653b205f29b3f9827a01a0c88bfbcb0d169494 Mon Sep 17 00:00:00 2001
From: Ye Bin <yebin10@huawei.com>
Date: Tue, 1 Sep 2020 14:25:44 +0800
Subject: [PATCH] dm thin metadata: Fix use-after-free in dm_bm_set_read_only
Git-commit: 3a653b205f29b3f9827a01a0c88bfbcb0d169494
Patch-mainline: v5.9-rc4
References: bsc#1177529
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: Ye Bin <yebin10@huawei.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Coly Li <colyli@suse.de>
---
drivers/md/dm-thin-metadata.c | 2 +-
drivers/md/persistent-data/dm-block-manager.c | 14 ++++++++------
2 files changed, 9 insertions(+), 7 deletions(-)
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index ddb7f1f0bc48..b461836b6d26 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -958,7 +958,7 @@ int dm_pool_metadata_close(struct dm_pool_metadata *pmd)
}
pmd_write_lock_in_core(pmd);
- 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",
diff --git a/drivers/md/persistent-data/dm-block-manager.c b/drivers/md/persistent-data/dm-block-manager.c
index 749ec268d957..54c089a50b15 100644
--- a/drivers/md/persistent-data/dm-block-manager.c
+++ b/drivers/md/persistent-data/dm-block-manager.c
@@ -493,7 +493,7 @@ 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);
@@ -562,7 +562,7 @@ 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);
@@ -602,7 +602,7 @@ 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);
@@ -616,19 +616,21 @@ 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)
{
- bm->read_only = true;
+ 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)
{
- bm->read_only = false;
+ if (bm)
+ bm->read_only = false;
}
EXPORT_SYMBOL_GPL(dm_bm_set_read_write);
--
2.26.2