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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, David Howells <dhowells@redhat.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.18 038/150] rxrpc: Fix transport sockopts to get IPv4 errors on an IPv6 socket
Date:   Fri,  2 Nov 2018 19:33:20 +0100
Message-Id: <20181102182905.990300511@linuxfoundation.org>
In-Reply-To: <20181102182902.250560510@linuxfoundation.org>
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4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 37a675e768d7606fe8a53e0c459c9b53e121ac20 ]

It seems that enabling IPV6_RECVERR on an IPv6 socket doesn't also turn on
IP_RECVERR, so neither local errors nor ICMP-transported remote errors from
IPv4 peer addresses are returned to the AF_RXRPC protocol.

Make the sockopt setting code in rxrpc_open_socket() fall through from the
AF_INET6 case to the AF_INET case to turn on all the AF_INET options too in
the AF_INET6 case.

Fixes: f2aeed3a591f ("rxrpc: Fix error reception on AF_INET6 sockets")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/rxrpc/local_object.c | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c
index 5d89ea5c1976..386dc1f20c73 100644
--- a/net/rxrpc/local_object.c
+++ b/net/rxrpc/local_object.c
@@ -135,10 +135,10 @@ static int rxrpc_open_socket(struct rxrpc_local *local, struct net *net)
 	}
 
 	switch (local->srx.transport.family) {
-	case AF_INET:
-		/* we want to receive ICMP errors */
+	case AF_INET6:
+		/* we want to receive ICMPv6 errors */
 		opt = 1;
-		ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR,
+		ret = kernel_setsockopt(local->socket, SOL_IPV6, IPV6_RECVERR,
 					(char *) &opt, sizeof(opt));
 		if (ret < 0) {
 			_debug("setsockopt failed");
@@ -146,19 +146,22 @@ static int rxrpc_open_socket(struct rxrpc_local *local, struct net *net)
 		}
 
 		/* we want to set the don't fragment bit */
-		opt = IP_PMTUDISC_DO;
-		ret = kernel_setsockopt(local->socket, SOL_IP, IP_MTU_DISCOVER,
+		opt = IPV6_PMTUDISC_DO;
+		ret = kernel_setsockopt(local->socket, SOL_IPV6, IPV6_MTU_DISCOVER,
 					(char *) &opt, sizeof(opt));
 		if (ret < 0) {
 			_debug("setsockopt failed");
 			goto error;
 		}
-		break;
 
-	case AF_INET6:
+		/* Fall through and set IPv4 options too otherwise we don't get
+		 * errors from IPv4 packets sent through the IPv6 socket.
+		 */
+
+	case AF_INET:
 		/* we want to receive ICMP errors */
 		opt = 1;
-		ret = kernel_setsockopt(local->socket, SOL_IPV6, IPV6_RECVERR,
+		ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR,
 					(char *) &opt, sizeof(opt));
 		if (ret < 0) {
 			_debug("setsockopt failed");
@@ -166,8 +169,8 @@ static int rxrpc_open_socket(struct rxrpc_local *local, struct net *net)
 		}
 
 		/* we want to set the don't fragment bit */
-		opt = IPV6_PMTUDISC_DO;
-		ret = kernel_setsockopt(local->socket, SOL_IPV6, IPV6_MTU_DISCOVER,
+		opt = IP_PMTUDISC_DO;
+		ret = kernel_setsockopt(local->socket, SOL_IP, IP_MTU_DISCOVER,
 					(char *) &opt, sizeof(opt));
 		if (ret < 0) {
 			_debug("setsockopt failed");
-- 
2.17.1