net: ping: Return EAFNOSUPPORT when appropriate.

1. For an IPv4 ping socket, ping_check_bind_addr does not check
   the family of the socket address that's passed in. Instead,
   make it behave like inet_bind, which enforces either that the
   address family is AF_INET, or that the family is AF_UNSPEC and
   the address is 0.0.0.0.
2. For an IPv6 ping socket, ping_check_bind_addr returns EINVAL
   if the socket family is not AF_INET6. Return EAFNOSUPPORT
   instead, for consistency with inet6_bind.
3. Make ping_v4_sendmsg and ping_v6_sendmsg return EAFNOSUPPORT
   instead of EINVAL if an incorrect socket address structure is
   passed in.
4. Make IPv6 ping sockets be IPv6-only. The code does not support
   IPv4, and it cannot easily be made to support IPv4 because
   the protocol numbers for ICMP and ICMPv6 are different. This
   makes connect(::ffff:192.0.2.1) fail with EAFNOSUPPORT instead
   of making the socket unusable.

Among other things, this fixes an oops that can be triggered by:

    int s = socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP);
    struct sockaddr_in6 sin6 = {
        .sin6_family = AF_INET6,
        .sin6_addr = in6addr_any,
    };
    bind(s, (struct sockaddr *) &sin6, sizeof(sin6));

Change-Id: If06ca86d9f1e4593c0d6df174caca3487c57a241
Signed-off-by: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 2 deletions

diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index e9f66e1cda50..208d5439e59b 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -259,6 +259,9 @@ int ping_init_sock(struct sock *sk)
         kgid_t low, high;
         int ret = 0;
 
+        if (sk->sk_family == AF_INET6)
+                sk->sk_ipv6only = 1;
+
         inet_get_ping_group_range_net(net, &low, &high);
         if (gid_lte(low, group) && gid_lte(group, high))
                 return 0;
@@ -305,6 +308,11 @@ static int ping_check_bind_addr(struct sock *sk, struct inet_sock *isk,
                 if (addr_len < sizeof(*addr))
                         return -EINVAL;
 
+                if (addr->sin_family != AF_INET &&
+                    !(addr->sin_family == AF_UNSPEC &&
+                      addr->sin_addr.s_addr == htonl(INADDR_ANY)))
+                        return -EAFNOSUPPORT;
+
                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI4,port=%d)\n",
                          sk, &addr->sin_addr.s_addr, ntohs(addr->sin_port));
 
@@ -330,7 +338,7 @@ static int ping_check_bind_addr(struct sock *sk, struct inet_sock *isk,
                         return -EINVAL;
 
                 if (addr->sin6_family != AF_INET6)
-                        return -EINVAL;
+                        return -EAFNOSUPPORT;
 
                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI6c,port=%d)\n",
                          sk, addr->sin6_addr.s6_addr, ntohs(addr->sin6_port));
@@ -716,7 +724,7 @@ static int ping_v4_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *m
                 if (msg->msg_namelen < sizeof(*usin))
                         return -EINVAL;
                 if (usin->sin_family != AF_INET)
-                        return -EINVAL;
+                        return -EAFNOSUPPORT;
                 daddr = usin->sin_addr.s_addr;
                 /* no remote port */
         } else {