netdev - Re: [PATCH net 1/2] ipv6: enforce flowi6_oif usage in ip6_dst_lookup

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Message-ID: <56AA2CE5.2050307@cumulusnetworks.com>
Date:	Thu, 28 Jan 2016 07:59:49 -0700
From:	David Ahern <dsa@...ulusnetworks.com>
To:	Paolo Abeni <pabeni@...hat.com>, netdev@...r.kernel.org
Cc:	"David S. Miller" <davem@...emloft.net>,
	Hajime Tazaki <thehajime@...il.com>, lucien.xin@...il.com,
	Marcelo Ricardo Leitner <marcelo.leitner@...il.com>
Subject: Re: [PATCH net 1/2] ipv6: enforce flowi6_oif usage in
 ip6_dst_lookup_tail()

On 1/27/16 6:45 AM, Paolo Abeni wrote:
> The current implementation of ip6_dst_lookup_tail() basically
> ignore the egress ifindex match: if the saddr is set,
> ip6_route_output() purposefully ignores flowi6_oif, due
> to the commit d46a9d678e4c ("net: ipv6: Dont add RT6_LOOKUP_F_IFACE
> flag if saddr set"), if the saddr is 'any' the first route lookup
> in ip6_dst_lookup_tail fails, but upon failure a second lookup will
> be performed with saddr set, thus ignoring the ifindex constraint.
>
> This commit adds an output route lookup function variant, which
> allows the caller to specify additional lookup flags, and modify
> ip6_dst_lookup_tail() to enforce the ifindex match on the second
> lookup via said helper.
>
> Fixes: d46a9d678e4c ("net: ipv6: Dont add RT6_LOOKUP_F_IFACE flag if saddr set")
> Signed-off-by: Paolo Abeni <pabeni@...hat.com>

I don't agree with that 'Fixes:' tag.

ip6_route_output did not add the RT6_LOOKUP_F_IFACE flag until 
741a11d9e410; d46a9d678e4c is a follow on to limit adding the flag only 
if no source address  is given.

Since ip6_dst_lookup_tail never considered the flowi6_oif this is a 
general bug fix rather than a fix of d46a9d678e4c.