Re: FAILED: patch "[PATCH] ipv6: Check attribute length for RTA_GATEWAY in multipath" failed to apply to 4.4-stable tree

[Pavel Machek <pavel@ucw.cz>]

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Hi!

> The patch below does not apply to the 4.4-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.

I could not find better place to reply.

I see this patch is queued for 5.10 and 4.19. But it is wrong:

> >From 4619bcf91399f00a40885100fb61d594d8454033 Mon Sep 17 00:00:00 2001
> From: David Ahern <dsahern@kernel.org>
> Date: Thu, 30 Dec 2021 17:36:33 -0700
> Subject: [PATCH] ipv6: Check attribute length for RTA_GATEWAY in multipath
>  route
> 
> 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)")

...> @@ -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;
> +

Direct return may not be used here. It needs to goto cleanup.

It is already fixed in mainline, so you can probably just cherry-pick
followup patch, too.

Best regards,
							Pavel
-- 
http://www.livejournal.com/~pavelmachek

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