[PATCH 5.18 137/339] net: ping6: Fix ping -6 with interface name

[Greg Kroah-Hartman]

From: Aya Levin <ayal@xxxxxxxxxx>

[ Upstream commit e6652a8ef3e64d953168a95878fe29b934ad78ac ]

When passing interface parameter to ping -6:
$ ping -6 ::11:141:84:9 -I eth2
Results in:
PING ::11:141:84:10(::11:141:84:10) from ::11:141:84:9 eth2: 56 data bytes
ping: sendmsg: Invalid argument
ping: sendmsg: Invalid argument

Initialize the fl6's outgoing interface (OIF) before triggering
ip6_datagram_send_ctl. Don't wipe fl6 after ip6_datagram_send_ctl() as
changes in fl6 that may happen in the function are overwritten explicitly.
Update comment accordingly.

Fixes: 13651224c00b ("net: ping6: support setting basic SOL_IPV6 options via cmsg")
Signed-off-by: Aya Levin <ayal@xxxxxxxxxx>
Reviewed-by: Gal Pressman <gal@xxxxxxxxxx>
Reviewed-by: Saeed Mahameed <saeedm@xxxxxxxxxx>
Signed-off-by: Tariq Toukan <tariqt@xxxxxxxxxx>
Reviewed-by: David Ahern <dsahern@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220531084544.15126-1-tariqt@xxxxxxxxxx
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 net/ipv6/ping.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/ipv6/ping.c b/net/ipv6/ping.c
index ff033d16549e..ecf3a553a0dc 100644
--- a/net/ipv6/ping.c
+++ b/net/ipv6/ping.c
@@ -101,6 +101,9 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	ipc6.sockc.tsflags = sk->sk_tsflags;
 	ipc6.sockc.mark = sk->sk_mark;
 
+	memset(&fl6, 0, sizeof(fl6));
+	fl6.flowi6_oif = oif;
+
 	if (msg->msg_controllen) {
 		struct ipv6_txoptions opt = {};
 
@@ -112,17 +115,14 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 			return err;
 
 		/* Changes to txoptions and flow info are not implemented, yet.
-		 * Drop the options, fl6 is wiped below.
+		 * Drop the options.
 		 */
 		ipc6.opt = NULL;
 	}
 
-	memset(&fl6, 0, sizeof(fl6));
-
 	fl6.flowi6_proto = IPPROTO_ICMPV6;
 	fl6.saddr = np->saddr;
 	fl6.daddr = *daddr;
-	fl6.flowi6_oif = oif;
 	fl6.flowi6_mark = ipc6.sockc.mark;
 	fl6.flowi6_uid = sk->sk_uid;
 	fl6.fl6_icmp_type = user_icmph.icmp6_type;
-- 
2.35.1