Re: [PATCH iproute2] ss: Fix allocation of cong control alg name

[Stephen Hemminger <stephen@networkplumber.org>]

On Fri, 29 May 2015 18:48:42 +0200
Daniel Borkmann <daniel@iogearbox.net> wrote:

> On 05/29/2015 06:17 PM, Guzman Mosqueda, Jose R wrote:
> > Hi Daniel and Vadim
> >
> > Thanks for your prompt response and for the patch.
> >
> > Also, what about the other one? Do you think it is an issue or not?
> >
> > " File: tc/tc_util.c
> > Function: void print_rate(char *buf, int len, __u64 rate)
> > Line: ~264
> >
> > In the case that user inputs a high value for rate, the "for" loop will exit in the condition meaning that variable "i" get the value of 5 which will be an invalid index for the "units" array due to that array has only 5 elements."
> >
> > I know a very high value is invalid but in the case that it comes directly from user, it could cause and issue, what do you think?
> 
> Hm, this prints just the netlink dump from kernel side, but perhaps
> we should just change it ...
> 
> diff --git a/tc/tc_util.c b/tc/tc_util.c
> index dc2b70f..aa6de24 100644
> --- a/tc/tc_util.c
> +++ b/tc/tc_util.c
> @@ -250,18 +250,19 @@ void print_rate(char *buf, int len, __u64 rate)
>   	extern int use_iec;
>   	unsigned long kilo = use_iec ? 1024 : 1000;
>   	const char *str = use_iec ? "i" : "";
> -	int i = 0;
>   	static char *units[5] = {"", "K", "M", "G", "T"};
> +	int i;
> 
>   	rate <<= 3; /* bytes/sec -> bits/sec */
> 
> -	for (i = 0; i < ARRAY_SIZE(units); i++)  {
> +	for (i = 0; i < ARRAY_SIZE(units) - 1; i++)  {
>   		if (rate < kilo)
>   			break;
>   		if (((rate % kilo) != 0) && rate < 1000*kilo)
>   			break;
>   		rate /= kilo;
>   	}
> +
>   	snprintf(buf, len, "%.0f%s%sbit", (double)rate, units[i], str);
>   }

I don't know what thread you meant to hijack for this, but it wasn't the
one about ss: cong name.