inet: fix addr_len/msg->msg_namelen assignment in recv_error and rxpmtu functions

Commit bceaa90240b6019ed73b49965eac7d167610be69 ("inet: prevent leakage
of uninitialized memory to user in recv syscalls") conditionally updated
addr_len if the msg_name is written to. The recv_error and rxpmtu
functions relied on the recvmsg functions to set up addr_len before.

As this does not happen any more we have to pass addr_len to those
functions as well and set it to the size of the corresponding sockaddr
length.

This broke traceroute and such.

Fixes: bceaa90240b6 ("inet: prevent leakage of uninitialized memory to user in recv syscalls")
Reported-by: Brad Spengler <spender@grsecurity.net>
Reported-by: Tom Labanowski
Cc: mpb <mpb.mail@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ip.h b/include/net/ip.h
index 217bc5b..5a25f36 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -473,7 +473,7 @@
 int ip_ra_control(struct sock *sk, unsigned char on,
 		  void (*destructor)(struct sock *));
 
-int ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
+int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
 void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
 		   u32 info, u8 *payload);
 void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 2a5f668..eb198ac 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -776,8 +776,10 @@
 
 int ip6_datagram_connect(struct sock *sk, struct sockaddr *addr, int addr_len);
 
-int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len);
-int ipv6_recv_rxpmtu(struct sock *sk, struct msghdr *msg, int len);
+int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len,
+		    int *addr_len);
+int ipv6_recv_rxpmtu(struct sock *sk, struct msghdr *msg, int len,
+		     int *addr_len);
 void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
 		     u32 info, u8 *payload);
 void ipv6_local_error(struct sock *sk, int err, struct flowi6 *fl6, u32 info);
diff --git a/include/net/ping.h b/include/net/ping.h
index 3f67704..90f4841 100644
--- a/include/net/ping.h
+++ b/include/net/ping.h
@@ -31,7 +31,8 @@
 
 /* Compatibility glue so we can support IPv6 when it's compiled as a module */
 struct pingv6_ops {
-	int (*ipv6_recv_error)(struct sock *sk, struct msghdr *msg, int len);
+	int (*ipv6_recv_error)(struct sock *sk, struct msghdr *msg, int len,
+			       int *addr_len);
 	int (*ip6_datagram_recv_ctl)(struct sock *sk, struct msghdr *msg,
 				     struct sk_buff *skb);
 	int (*icmpv6_err_convert)(u8 type, u8 code, int *err);