netdev - Re: [PATCH] tools/bpftool: silence a static check warning

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Message-ID: <2c2c2cf6-acf2-af9f-83ef-21dbcd0a5551@iogearbox.net>
Date:   Mon, 15 Jan 2018 11:35:06 +0100
From:   Daniel Borkmann <daniel@...earbox.net>
To:     Dan Carpenter <dan.carpenter@...cle.com>,
        Alexei Starovoitov <ast@...nel.org>
Cc:     netdev@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] tools/bpftool: silence a static check warning

Hi Dan,

On 01/15/2018 09:15 AM, Dan Carpenter wrote:
> There is a static checker warning that proglen has an upper bound but no
> lower bound.  The allocation will just fail harmlessly so it's not a big
> deal.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
> 
> diff --git a/tools/bpf/bpf_jit_disasm.c b/tools/bpf/bpf_jit_disasm.c
> index 30044bc4f389..2d7bb5dc0b8c 100644
> --- a/tools/bpf/bpf_jit_disasm.c
> +++ b/tools/bpf/bpf_jit_disasm.c
> @@ -205,7 +205,7 @@ static uint8_t *get_last_jit_image(char *haystack, size_t hlen,
>  		regfree(&regex);
>  		return NULL;
>  	}
> -	if (proglen > 1000000) {
> +	if (proglen < 0 || proglen > 1000000) {

Could you just change proglen into unsigned? It's parsing the bpf_jit_dump()
and there we use proglen=%u anyway.

>  		printf("proglen of %d too big, stopping\n", proglen);
>  		return NULL;
>  	}
> 

Thanks,
Daniel