Re: [PATCH net 3/5] ipv6: Check attribute length for RTA_GATEWAY in multipath route

[Nicolas Dichtel <nicolas.dichtel@6wind.com>]

Le 31/12/2021 à 01:36, David Ahern a écrit :
> Commit referenced in the Fixes tag used nla_memcpy for RTA_GATEWAY as
> does the current nla_get_in6_addr. nla_memcpy protects against accessing
> memory greater than what is in the attribute, but there is no check
> requiring the attribute to have an IPv6 address. Add it.
> 
> Fixes: 51ebd3181572 ("ipv6: add support of equal cost multipath (ECMP)")
> Signed-off-by: David Ahern <dsahern@kernel.org>
> Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
> ---
>  net/ipv6/route.c | 21 ++++++++++++++++++++-
>  1 file changed, 20 insertions(+), 1 deletion(-)
> 
[snip]
> @@ -5264,7 +5277,13 @@ static int ip6_route_multipath_add(struct fib6_config *cfg,
>  
>  			nla = nla_find(attrs, attrlen, RTA_GATEWAY);
>  			if (nla) {
> -				r_cfg.fc_gateway = nla_get_in6_addr(nla);
> +				int ret;
> +
> +				ret = fib6_gw_from_attr(&r_cfg.fc_gateway, nla,
> +							extack);
> +				if (ret)
> +					return ret;
A 'goto cleanup;' is needed is case of error.