Subject: Re: [patch -next] bpf: off by one in check_map_func_compatibility()

From: Daniel Borkmann <[email-masked]>
Date: Thu, 13 Aug 2015 22:31:50 +0200

On 08/13/2015 10:27 PM, Dan Carpenter wrote:
> The loop iterates one space too far, so we might read beyond the end of
> the func_limit[] array.
>
> Fixes: 35578d798400 ('bpf: Implement function bpf_perf_event_read() that get the selected hardware PMU conuter')
> Signed-off-by: Dan Carpenter <[email-masked]>

Thanks for the fix, Dan!

There's however already one queued up here:

https://git.kernel.org/cgit/linux/kernel/git/davem/net-next.git/commit/?id=140d8b335a9beb234fd0ed9a15aa6a47f47fd771

> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index 48e1c71..ed12e38 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -853,7 +853,7 @@ static int check_map_func_compatibility(struct bpf_map *map, int func_id)
>   	if (!map)
>   		return 0;
>
> -	for (i = 0; i <= ARRAY_SIZE(func_limit); i++) {
> +	for (i = 0; i < ARRAY_SIZE(func_limit); i++) {
>   		bool_map = (map->map_type == func_limit[i].map_type);
>   		bool_func = (func_id == func_limit[i].func_id);
>   		/* only when map & func pair match it can continue.
> --
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