net: Add compat support for getsockopt (MCAST_MSFILTER)

This patch adds support for getsockopt for MCAST_MSFILTER for
both IPv4 and IPv6. It depends on the previous setsockopt patch,
and uses the same method.
Signed-off-by: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/compat.h

@@ -42,5 +42,8 @@ extern int cmsghdr_from_user_compat_to_kern(struct msghdr *, struct sock *, unsi
 
 extern int compat_mc_setsockopt(struct sock *, int, int, char __user *, int,
 	int (*)(struct sock *, int, int, char __user *, int));
+extern int compat_mc_getsockopt(struct sock *, int, int, char __user *,
+	int __user *, int (*)(struct sock *, int, int, char __user *,
+				int __user *));
 
 #endif /* NET_COMPAT_H */

net/compat.c

@@ -640,6 +640,85 @@ int compat_mc_setsockopt(struct sock *sock, int level, int optname,
 
 EXPORT_SYMBOL(compat_mc_setsockopt);
 
+int compat_mc_getsockopt(struct sock *sock, int level, int optname,
+	char __user *optval, int __user *optlen,
+	int (*getsockopt)(struct sock *,int,int,char __user *,int __user *))
+{
+	struct compat_group_filter __user *gf32 = (void *)optval;
+	struct group_filter __user *kgf;
+	int __user	*koptlen;
+	u32 interface, fmode, numsrc;
+	int klen, ulen, err;
+
+	if (optname != MCAST_MSFILTER)
+		return getsockopt(sock, level, optname, optval, optlen);
+
+	koptlen = compat_alloc_user_space(sizeof(*koptlen));
+	if (!access_ok(VERIFY_READ, optlen, sizeof(*optlen)) ||
+	    __get_user(ulen, optlen))
+		return -EFAULT;
+
+	/* adjust len for pad */
+	klen = ulen + sizeof(*kgf) - sizeof(*gf32);
+
+	if (klen < GROUP_FILTER_SIZE(0))
+		return -EINVAL;
+
+	if (!access_ok(VERIFY_WRITE, koptlen, sizeof(*koptlen)) ||
+	    __put_user(klen, koptlen))
+		return -EFAULT;
+
+	/* have to allow space for previous compat_alloc_user_space, too */
+	kgf = compat_alloc_user_space(klen+sizeof(*optlen));
+
+	if (!access_ok(VERIFY_READ, gf32, __COMPAT_GF0_SIZE) ||
+	    __get_user(interface, &gf32->gf_interface) ||
+	    __get_user(fmode, &gf32->gf_fmode) ||
+	    __get_user(numsrc, &gf32->gf_numsrc) ||
+	    __put_user(interface, &kgf->gf_interface) ||
+	    __put_user(fmode, &kgf->gf_fmode) ||
+	    __put_user(numsrc, &kgf->gf_numsrc) ||
+	    copy_in_user(&kgf->gf_group,&gf32->gf_group,sizeof(kgf->gf_group)))
+		return -EFAULT;
+
+	err = getsockopt(sock, level, optname, (char __user *)kgf, koptlen);
+	if (err)
+		return err;
+
+	if (!access_ok(VERIFY_READ, koptlen, sizeof(*koptlen)) ||
+	    __get_user(klen, koptlen))
+		return -EFAULT;
+
+	ulen = klen - (sizeof(*kgf)-sizeof(*gf32));
+
+	if (!access_ok(VERIFY_WRITE, optlen, sizeof(*optlen)) ||
+	    __put_user(ulen, optlen))
+		return -EFAULT;
+
+	if (!access_ok(VERIFY_READ, kgf, klen) ||
+	    !access_ok(VERIFY_WRITE, gf32, ulen) ||
+	    __get_user(interface, &kgf->gf_interface) ||
+	    __get_user(fmode, &kgf->gf_fmode) ||
+	    __get_user(numsrc, &kgf->gf_numsrc) ||
+	    __put_user(interface, &gf32->gf_interface) ||
+	    __put_user(fmode, &gf32->gf_fmode) ||
+	    __put_user(numsrc, &gf32->gf_numsrc))
+		return -EFAULT;
+	if (numsrc) {
+		int copylen;
+
+		klen -= GROUP_FILTER_SIZE(0);
+		copylen = numsrc * sizeof(gf32->gf_slist[0]);
+		if (copylen > klen)
+			copylen = klen;
+	        if (copy_in_user(gf32->gf_slist, kgf->gf_slist, copylen))
+			return -EFAULT;
+	}
+	return err;
+}
+
+EXPORT_SYMBOL(compat_mc_getsockopt);
+
 
 /* Argument list sizes for compat_sys_socketcall */
 #define AL(x) ((x) * sizeof(u32))

net/ipv4/ip_sockglue.c

@@ -1186,7 +1186,14 @@ int ip_getsockopt(struct sock *sk, int level,
 int compat_ip_getsockopt(struct sock *sk, int level, int optname,
 			 char __user *optval, int __user *optlen)
 {
-	int err = do_ip_getsockopt(sk, level, optname, optval, optlen);
+	int err;
+
+	if (optname == MCAST_MSFILTER)
+		return compat_mc_getsockopt(sk, level, optname, optval, optlen,
+			ip_getsockopt);
+
+	err = do_ip_getsockopt(sk, level, optname, optval, optlen);
+
 #ifdef CONFIG_NETFILTER
 	/* we need to exclude all possible ENOPROTOOPTs except default case */
 	if (err == -ENOPROTOOPT && optname != IP_PKTOPTIONS &&

net/ipv6/ipv6_sockglue.c

@@ -1089,6 +1089,10 @@ int ipv6_getsockopt(struct sock *sk, int level, int optname,
 	if(level != SOL_IPV6)
 		return -ENOPROTOOPT;
 
+	if (optname == MCAST_MSFILTER)
+		return compat_mc_getsockopt(sk, level, optname, optval, optlen,
+			ipv6_getsockopt);
+
 	err = do_ipv6_getsockopt(sk, level, optname, optval, optlen);
 #ifdef CONFIG_NETFILTER
 	/* we need to exclude all possible ENOPROTOOPTs except default case */