Affected: Alpaquita:23: linux-lts, Alpaquita:25: linux-lts, Alpaquita:stream: linux-lts

In the Linux kernel, the following vulnerability has been resolved:

null_blk: free zones array on device power-off

null_init_zoned_dev() allocates dev->zones when a zoned device is powered on, but null_del_dev() never frees it on power-off; dev->zones is only freed later in null_free_dev(), when the configfs directory is removed. If the device is powered off and then on again, null_init_zoned_dev() allocates a new array and overwrites the dev->zones pointer, leaking the previous allocation each power cycle.

Free dev->zones in null_del_dev() via null_free_zoned_dev() to solve it. And calling null_free_zoned_dev() in null_free_dev() is no longer necessary because every caller already invokes null_del_dev() first: via nullb_group_drop_item() before nullb_device_release(), in the null_add_dev() error path of null_create_dev(), and in null_destroy_dev(). Remove the redundant call.

And take &lock around zone_cond_store() in the two store wrappers to serialize dev->zones check-and-deref against its alloc/free, which already run under &lock. The reason there was no problem before is that only nullb_device_release() or null_exit() frees the dev->zones, which guarantees that subsequent users won't access the configfs interface.

In the Linux kernel, the following vulnerability has been resolved:

null_blk: free zones array on device power-off

null_init_zoned_dev() allocates dev->zones when a zoned device is powered on, but null_del_dev() never frees it on power-off; dev->zones is only freed later in null_free_dev(), when the configfs directory is removed. If the device is powered off and then on again, null_init_zoned_dev() allocates a new array and overwrites the dev->zones pointer, leaking the previous allocation each power cycle.

Free dev->zones in null_del_dev() via null_free_zoned_dev() to solve it. And calling null_free_zoned_dev() in null_free_dev() is no longer necessary because every caller already invokes null_del_dev() first: via nullb_group_drop_item() before nullb_device_release(), in the null_add_dev() error path of null_create_dev(), and in null_destroy_dev(). Remove the redundant call.

And take &lock around zone_cond_store() in the two store wrappers to serialize dev->zones check-and-deref against its alloc/free, which already run under &lock. The reason there was no problem before is that only nullb_device_release() or null_exit() frees the dev->zones, which guarantees that subsequent users won't access the configfs interface.

kernel-devel-7.2.7-1.1 on GA media

Affected: Ubuntu:16.04:LTS: linux-hwe-edge, Ubuntu:18.04:LTS: linux-aws-5.0, Ubuntu:18.04:LTS: linux-aws-5.3, Ubuntu:Pro:18.04:LTS: linux-aws-5.4, Ubuntu:18.04:LTS: linux-azure, Ubuntu:18.04:LTS: linux-azure-5.3, Ubuntu:Pro:18.04:LTS: linux-azure-5.4, Ubuntu:18.04:LTS: linux-azure-edge, Ubuntu:18.04:LTS: linux-gcp, Ubuntu:18.04:LTS: linux-gcp-5.3 and 219 more

In the Linux kernel, the following vulnerability has been resolved: null_blk: free zones array on device power-off null_init_zoned_dev() allocates dev->zones when a zoned device is powered on, but null_del_dev() never frees it on power-off; dev->zones is only freed later in null_free_dev(), when the configfs directory is removed. If the device is powered off and then on again, null_init_zoned_dev() allocates a new array and overwrites the dev->zones pointer, leaking the previous allocation each power cycle. Free dev->zones in null_del_dev() via null_free_zoned_dev() to solve it. And calling null_free_zoned_dev() in null_free_dev() is no longer necessary because every caller already invokes null_del_dev() first: via nullb_group_drop_item() before nullb_device_release(), in the null_add_dev() error path of null_create_dev(), and in null_destroy_dev(). Remove the redundant call. And take &lock around zone_cond_store() in the two store wrappers to serialize dev->zones check-and-deref against its alloc/free, which already run under &lock. The reason there was no problem before is that only nullb_device_release() or null_exit() frees the dev->zones, which guarantees that subsequent users won't access the configfs interface.