[PATCH 4.14 74/77] rxrpc: Fix transport sockopts to get IPv4 errors on an IPv6 socket

From: Greg Kroah-Hartman
Date: Mon Jun 01 2020 - 14:54:11 EST


From: David Howells <dhowells@xxxxxxxxxx>

commit 37a675e768d7606fe8a53e0c459c9b53e121ac20 upstream.

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@xxxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
net/rxrpc/local_object.c | 23 +++++++++++++----------
1 file changed, 13 insertions(+), 10 deletions(-)

--- a/net/rxrpc/local_object.c
+++ b/net/rxrpc/local_object.c
@@ -134,10 +134,10 @@ static int rxrpc_open_socket(struct rxrp
}

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");
@@ -145,19 +145,22 @@ static int rxrpc_open_socket(struct rxrp
}

/* 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");
@@ -165,8 +168,8 @@ static int rxrpc_open_socket(struct rxrp
}

/* 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");