diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2023-08-09 12:44:20 +0200 |
|---|---|---|
| committer | Mike Snitzer <snitzer@kernel.org> | 2023-09-14 11:18:29 -0400 |
| commit | f6007dce0cd35d634d9be91ef3515a6385dcee16 (patch) | |
| tree | 663ba934a3a55514c73ef0e397c994ac3e4a3358 /drivers/md/dm-core.h | |
| parent | 0bb80ecc33a8fb5a682236443c1e740d5c917d1d (diff) | |
| download | lwn-f6007dce0cd35d634d9be91ef3515a6385dcee16.tar.gz lwn-f6007dce0cd35d634d9be91ef3515a6385dcee16.zip | |
dm: fix a race condition in retrieve_deps
There's a race condition in the multipath target when retrieve_deps
races with multipath_message calling dm_get_device and dm_put_device.
retrieve_deps walks the list of open devices without holding any lock
but multipath may add or remove devices to the list while it is
running. The end result may be memory corruption or use-after-free
memory access.
See this description of a UAF with multipath_message():
https://listman.redhat.com/archives/dm-devel/2022-October/052373.html
Fix this bug by introducing a new rw semaphore "devices_lock". We grab
devices_lock for read in retrieve_deps and we grab it for write in
dm_get_device and dm_put_device.
Reported-by: Luo Meng <luomeng12@huawei.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Tested-by: Li Lingfeng <lilingfeng3@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Diffstat (limited to 'drivers/md/dm-core.h')
| -rw-r--r-- | drivers/md/dm-core.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h index 0d93661f88d3..095b9b49aa82 100644 --- a/drivers/md/dm-core.h +++ b/drivers/md/dm-core.h @@ -214,6 +214,7 @@ struct dm_table { /* a list of devices used by this table */ struct list_head devices; + struct rw_semaphore devices_lock; /* events get handed up using this callback */ void (*event_fn)(void *data); |