Re: [patch] [bugfix] loop.c

[Jiri Kosina]

On Fri, 23 Mar 2007, Eric Dumazet wrote:

> -	if (max_loop < 1 || max_loop > 256) {
> -		printk(KERN_WARNING "loop: invalid max_loop (must be between"
> -				    " 1 and 256), using default (8)\n");
> +	if (max_loop < 1) {
> +		printk(KERN_WARNING "loop: invalid max_loop (must be > 1)"
> +				    ", using default (8)\n");
>  		max_loop = 8;
>  	}
[...]
> +	loop_dev = kmalloc(max_loop * sizeof(struct loop_device *), GFP_KERNEL);
> +	if (!loop_dev) {
> +		loop_dev = vmalloc(max_loop * sizeof(struct loop_device *));
> +		if (!loop_dev)
> +			goto out_mem;
> +		loop_dev_vmalloced = 1;
>  	}

Why did you remove the upper bound check for max_loop value? Now you 
effectively allow to max_loop * sizeof(struct loop_device *) to overflow, 
when passed value of max_loop which is large enough. Or am I just blind?

The "while (nbl < max_loop)" which immediately follows is then going to 
corrupt memory, right?

-- 
Jiri Kosina
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