Re: [PATCH] scsi: target: core: Fix null-ptr-deref in target_alloc_device()

[michael.christie@oracle.com]

On 10/11/24 6:34 AM, Wang Hai wrote:
> There is a null-ptr-deref issue reported by kasan:
> 
> BUG: KASAN: null-ptr-deref in target_alloc_device+0xbc4/0xbe0 [target_core_mod]
> ...
>  kasan_report+0xb9/0xf0
>  target_alloc_device+0xbc4/0xbe0 [target_core_mod]
>  core_dev_setup_virtual_lun0+0xef/0x1f0 [target_core_mod]
>  target_core_init_configfs+0x205/0x420 [target_core_mod]
>  do_one_initcall+0xdd/0x4e0
> ...
>  entry_SYSCALL_64_after_hwframe+0x76/0x7e
> 
> In target_alloc_device(), if allocing memory for dev queues fails,
> then dev will be freed by dev->transport->free_device(), but
> dev->transport is not initialized at that time, which will lead to a
> null pointer reference problem.
> 
> Fixing this bug by freeing dev with hba->backend->ops->free_device().
> 
> Fixes: 1526d9f10c61 ("scsi: target: Make state_list per CPU")
> Signed-off-by: Wang Hai <wanghai38@huawei.com>
> ---
>  drivers/target/target_core_device.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
> index bf4892544cfd..bb84d304b07e 100644
> --- a/drivers/target/target_core_device.c
> +++ b/drivers/target/target_core_device.c
> @@ -691,7 +691,7 @@ struct se_device *target_alloc_device(struct se_hba *hba, const char *name)
>  
>  	dev->queues = kcalloc(nr_cpu_ids, sizeof(*dev->queues), GFP_KERNEL);
>  	if (!dev->queues) {
> -		dev->transport->free_device(dev);
> +		hba->backend->ops->free_device(dev);
>  		return NULL;
>  	}
>  

Thanks.

Reviewed-by: Mike Christie <michael.christie@oracle.com>