[IPV4/IPV6]: Add sysctl limits for mcast src filters.

include/linux/sysctl.h

@@ -405,7 +405,8 @@ enum {
 	NET_IPV6_IP6FRAG_HIGH_THRESH=21,
 	NET_IPV6_IP6FRAG_LOW_THRESH=22,
 	NET_IPV6_IP6FRAG_TIME=23,
-	NET_IPV6_IP6FRAG_SECRET_INTERVAL=24
+	NET_IPV6_IP6FRAG_SECRET_INTERVAL=24,
+	NET_IPV6_MLD_MAX_MSF=25,
 };
 
 enum {

include/net/ipv6.h

@@ -108,6 +108,7 @@ struct frag_hdr {
 
 /* sysctls */
 extern int sysctl_ipv6_bindv6only;
+extern int sysctl_mld_max_msf;
 
 /* MIBs */
 DECLARE_SNMP_STAT(struct ipv6_mib, ipv6_statistics);

net/ipv4/ip_sockglue.c

@@ -771,6 +771,8 @@ int ip_setsockopt(struct sock *sk, int level, int optname, char *optval, int opt
 		}
 		case MCAST_MSFILTER:
 		{
+			extern int sysctl_optmem_max;
+			extern int sysctl_igmp_max_msf;
 			struct sockaddr_in *psin;
 			struct ip_msfilter *msf = 0;
 			struct group_filter *gsf = 0;
@@ -778,6 +780,10 @@ int ip_setsockopt(struct sock *sk, int level, int optname, char *optval, int opt
 
 			if (optlen < GROUP_FILTER_SIZE(0))
 				goto e_inval;
+			if (optlen > sysctl_optmem_max) {
+				err = -ENOBUFS;
+				break;
+			}
 			gsf = (struct group_filter *)kmalloc(optlen,GFP_KERNEL);
 			if (gsf == 0) {
 				err = -ENOBUFS;
@@ -787,7 +793,13 @@ int ip_setsockopt(struct sock *sk, int level, int optname, char *optval, int opt
 			if (copy_from_user(gsf, optval, optlen)) {
 				goto mc_msf_out;
 			}
-			if (GROUP_FILTER_SIZE(gsf->gf_numsrc) < optlen) {
+			/* numsrc >= (4G-140)/128 overflow in 32 bits */
+			if (gsf->gf_numsrc >= 0x1ffffff ||
+			    gsf->gf_numsrc > sysctl_igmp_max_msf) {
+				err = -ENOBUFS;
+				goto mc_msf_out;
+			}
+			if (GROUP_FILTER_SIZE(gsf->gf_numsrc) > optlen) {
 				err = EINVAL;
 				goto mc_msf_out;
 			}

net/ipv6/ipv6_sockglue.c

@@ -437,6 +437,7 @@ int ipv6_setsockopt(struct sock *sk, int level, int optname, char *optval,
 	case MCAST_MSFILTER:
 	{
 		extern int sysctl_optmem_max;
+		extern int sysctl_mld_max_msf;
 		struct group_filter *gsf;
 
 		if (optlen < GROUP_FILTER_SIZE(0))
@@ -455,8 +456,14 @@ int ipv6_setsockopt(struct sock *sk, int level, int optname, char *optval,
 			kfree(gsf);
 			break;
 		}
-		if (GROUP_FILTER_SIZE(gsf->gf_numsrc) < GROUP_FILTER_SIZE(0) ||
-		    GROUP_FILTER_SIZE(gsf->gf_numsrc) > optlen) {
+		/* numsrc >= (4G-140)/128 overflow in 32 bits */
+		if (gsf->gf_numsrc >= 0x1ffffffU ||
+		    gsf->gf_numsrc > sysctl_mld_max_msf) {
+			kfree(gsf);
+			retv = -ENOBUFS;
+			break;
+		}
+		if (GROUP_FILTER_SIZE(gsf->gf_numsrc) > optlen) {
 			kfree(gsf);
 			retv = -EINVAL;
 			break;

net/ipv6/mcast.c

@@ -166,6 +166,10 @@ int ip6_mc_leave_src(struct sock *sk, struct ipv6_mc_socklist *iml,
 #define MLDV2_QQIC(value) MLDV2_EXP(0x80, 4, 3, value)
 #define MLDV2_MRC(value) MLDV2_EXP(0x8000, 12, 3, value)
 
+#define IPV6_MLD_MAX_MSF	10
+
+int sysctl_mld_max_msf = IPV6_MLD_MAX_MSF;
+
 /*
  *	socket join on multicast group
  */
@@ -404,6 +408,10 @@ int ip6_mc_source(int add, int omode, struct sock *sk,
 	}
 	/* else, add a new source to the filter */
 
+	if (psl && psl->sl_count >= sysctl_mld_max_msf) {
+		err = -ENOBUFS;
+		goto done;
+	}
 	if (!psl || psl->sl_count == psl->sl_max) {
 		struct ip6_sf_socklist *newpsl;
 		int count = IP6_SFBLOCK;

net/ipv6/sysctl_net_ipv6.c

@@ -76,6 +76,14 @@ ctl_table ipv6_table[] = {
 		.proc_handler	= &proc_dointvec_jiffies,
 		.strategy	= &sysctl_jiffies
 	},
+	{
+		.ctl_name	= NET_IPV6_MLD_MAX_MSF,
+		.procname	= "mld_max_msf",
+		.data		= &sysctl_mld_max_msf,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec
+	},
 	{ .ctl_name = 0 }
 };