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net: setsockopt: fix IPV6_UNICAST_IF option for connected sockets

PATCH Superseded Richard Gobert 2 participants 2 messages Nov 24, 2022 – Nov 25, 2022

Subsystems (2)
Networking Network drivers

v1 of 2 Superseded Latest is v2 →

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Richard Gobert

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#0 lore raw

PATCH 1/1 net: setsockopt: fix IPV6_UNICAST_IF option for connected sockets

Change the behaviour of ip6_datagram_connect to consider the interface set by the IPV6_UNICAST_IF socket option, similarly to udpv6_sendmsg.

This change is the IPv6 counterpart of the fix for IP_UNICAST_IF. The tests introduced by that patch showed that the incorrect behavior is present in IPv6 as well.
This patch fixes the broken test.

Reported-by kernel test robot <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Richard Gobert <[email protected]>
---
 net/ipv6/datagram.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)
net/ipv6/datagram.c +11 -5
index 7c7155b48f17..c3999f9e3545 100644
@@ -42,24 +42,30 @@ static void ip6_datagram_flow_key_init(struct flowi6 *fl6, struct sock *sk)
 {
 	struct inet_sock *inet = inet_sk(sk);
 	struct ipv6_pinfo *np = inet6_sk(sk);
+	int oif;
 
 	memset(fl6, 0, sizeof(*fl6));
 	fl6->flowi6_proto = sk->sk_protocol;
 	fl6->daddr = sk->sk_v6_daddr;
 	fl6->saddr = np->saddr;
-	fl6->flowi6_oif = sk->sk_bound_dev_if;
+	oif = sk->sk_bound_dev_if;
 	fl6->flowi6_mark = sk->sk_mark;
 	fl6->fl6_dport = inet->inet_dport;
 	fl6->fl6_sport = inet->inet_sport;
 	fl6->flowlabel = np->flow_label;
 	fl6->flowi6_uid = sk->sk_uid;
 
-	if (!fl6->flowi6_oif)
-		fl6->flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
+	if (!oif)
+		oif = np->sticky_pktinfo.ipi6_ifindex;
 
-	if (!fl6->flowi6_oif && ipv6_addr_is_multicast(&fl6->daddr))
-		fl6->flowi6_oif = np->mcast_oif;
+	if (!oif) {
+		if (ipv6_addr_is_multicast(&fl6->daddr))
+			oif = np->mcast_oif;
+		else
+			oif = np->ucast_oif;
+	}
 
+	fl6->flowi6_oif = oif;
 	security_sk_classify_flow(sk, flowi6_to_flowi_common(fl6));
 }
Signature · 1 line
2.36.1
Reviewed-by on v1 1/1
#1 lore raw
Quoted 11 lines · Richard Gobert

Change the behaviour of ip6_datagram_connect to consider the interface set by the IPV6_UNICAST_IF socket option, similarly to udpv6_sendmsg.

This change is the IPv6 counterpart of the fix for IP_UNICAST_IF. The tests introduced by that patch showed that the incorrect behavior is present in IPv6 as well.
This patch fixes the broken test.

Reported-by kernel test robot <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here

Fixes tag here.

Quoted 10 lines
Signed-off-by Richard Gobert <[email protected]>
---
 net/ipv6/datagram.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)
net/ipv6/datagram.c +0 -0
index 7c7155b48f17..c3999f9e3545 100644

net/ipv6/datagram.c static void ip6_datagram_flow_key_init(struct flowi6 *fl6, struct sock *sk) · line 45

Quoted 4 lines
net/ipv6/datagram.c +1 -0
@@ -42,24 +42,30 @@ static void ip6_datagram_flow_key_init(struct flowi6 *fl6, struct sock *sk)
 {
 	struct inet_sock *inet = inet_sk(sk);
 	struct ipv6_pinfo *np = inet6_sk(sk);
+	int oif;

	int oif = sk->sk_bound_dev_if;

net/ipv6/datagram.c static void ip6_datagram_flow_key_init(struct flowi6 *fl6, struct sock *sk) · line 51

Quoted 7 lines
net/ipv6/datagram.c +1 -1
 	memset(fl6, 0, sizeof(*fl6));
 	fl6->flowi6_proto = sk->sk_protocol;
 	fl6->daddr = sk->sk_v6_daddr;
 	fl6->saddr = np->saddr;
-	fl6->flowi6_oif = sk->sk_bound_dev_if;
+	oif = sk->sk_bound_dev_if;

and then drop this line in the middle of all of the fl6 setup.

Quoted 14 lines
net/ipv6/datagram.c +3 -4
 	fl6->flowi6_mark = sk->sk_mark;
 	fl6->fl6_dport = inet->inet_dport;
 	fl6->fl6_sport = inet->inet_sport;
 	fl6->flowlabel = np->flow_label;
 	fl6->flowi6_uid = sk->sk_uid;
 
-	if (!fl6->flowi6_oif)
-		fl6->flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
+	if (!oif)
+		oif = np->sticky_pktinfo.ipi6_ifindex;
 
-	if (!fl6->flowi6_oif && ipv6_addr_is_multicast(&fl6->daddr))
-		fl6->flowi6_oif = np->mcast_oif;
+	if (!oif) {

net/ipv6/datagram.c static void ip6_datagram_flow_key_init(struct flowi6 *fl6, struct sock *sk) · line 71

Quoted 10 lines
net/ipv6/datagram.c +6 -0
+		if (ipv6_addr_is_multicast(&fl6->daddr))
+			oif = np->mcast_oif;
+		else
+			oif = np->ucast_oif;
+	}
 
+	fl6->flowi6_oif = oif;
 	security_sk_classify_flow(sk, flowi6_to_flowi_common(fl6));
 }

thanks for the fix.

Besides the nit,

Reviewed-by David Ahern <[email protected]>