Re: [PATCH v3] android: binder: Sanity check at binder ioctl

[Chen Feng]

Add android kernel team.

On 2016/2/1 14:04, Chen Feng wrote:
> Sanity check at binder ioctl function,
> Only allow the shared mm_struct to use the same binder-object
> to do binder operate.
> 
> And add proc->vma_vm_mm = current->mm at the open function.
> The libbinder do ioctl before mmap called.
> 
> V2: Fix compile error for error commit
> V3: Change the condition to proc->vma_vm_mm
> 
> Signed-off-by: Chen Feng <puck.chen@xxxxxxxxxxxxx>
> Signed-off-by: Wei  Dong <weidong2@xxxxxxxxxxxxx>
> Signed-off-by: Junmin Zhao <zhaojunmin@xxxxxxxxxx>
> Reviewed-by: Zhuangluan Su <suzhuangluan@xxxxxxxxxxxxx>
> ---
>  drivers/android/binder.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/android/binder.c b/drivers/android/binder.c
> index a39e85f..f080a8b 100644
> --- a/drivers/android/binder.c
> +++ b/drivers/android/binder.c
> @@ -2737,6 +2737,10 @@ static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>  	/*pr_info("binder_ioctl: %d:%d %x %lx\n",
>  			proc->pid, current->pid, cmd, arg);*/
>  
> +	if (unlikely(current->mm != proc->vma_vm_mm)) {
> +		pr_err("current mm mismatch proc mm\n");
> +		return -EINVAL;
> +	}
>  	trace_binder_ioctl(cmd, arg);
>  
>  	ret = wait_event_interruptible(binder_user_error_wait, binder_stop_on_user_error < 2);
> @@ -2951,6 +2955,7 @@ static int binder_open(struct inode *nodp, struct file *filp)
>  		return -ENOMEM;
>  	get_task_struct(current);
>  	proc->tsk = current;
> +	proc->vma_vm_mm = current->mm;
>  	INIT_LIST_HEAD(&proc->todo);
>  	init_waitqueue_head(&proc->wait);
>  	proc->default_priority = task_nice(current);
>