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| author | Nikolay Borisov <nborisov@suse.com> | 2018-01-30 15:07:37 +0100 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2018-02-05 17:15:14 +0100 |
| commit | fd649f10c3d21ee9d7542c609f29978bdf73ab94 (patch) | |
| tree | a79f74afd161f3b51f6016ad806a60c89e9c2e20 /fs | |
| parent | Btrfs: fix null pointer dereference when replacing missing device (diff) | |
| download | linux-fd649f10c3d21ee9d7542c609f29978bdf73ab94.tar.xz linux-fd649f10c3d21ee9d7542c609f29978bdf73ab94.zip | |
btrfs: Fix use-after-free when cleaning up fs_devs with a single stale device
Commit 4fde46f0cc71 ("Btrfs: free the stale device") introduced
btrfs_free_stale_device which iterates the device lists for all
registered btrfs filesystems and deletes those devices which aren't
mounted. In a btrfs_devices structure has only 1 device attached to it
and it is unused then btrfs_free_stale_devices will proceed to also free
the btrfs_fs_devices struct itself. Currently this leads to a use after
free since list_for_each_entry will try to perform a check on the
already freed memory to see if it has to terminate the loop.
The fix is to use 'break' when we know we are freeing the current
fs_devs.
Fixes: 4fde46f0cc71 ("Btrfs: free the stale device")
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/volumes.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index b5036bd69e6a..2ceb924ca0d6 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -645,6 +645,7 @@ static void btrfs_free_stale_devices(const char *path, btrfs_sysfs_remove_fsid(fs_devs); list_del(&fs_devs->list); free_fs_devices(fs_devs); + break; } else { fs_devs->num_devices--; list_del(&dev->dev_list); |