Commit message: net: ipv4: current group_info should be put after using.

Plug a group_info refcount leak in ping_init.
group_info is only needed during initialization and
the code failed to release the reference on exit.
While here move grabbing the reference to a place
where it is actually needed.

Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Zhang Dongxing <dongxing.zhang@intel.com>
Signed-off-by: xiaoming wang <xiaoming.wang@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
CVE: CVE-2014-2851
CWE: CWE-416
Vulnerability description: Integer overflow in the ping_init_sock function in net/ipv4/ping.c in the Linux kernel through 3.14.1 allows local users to cause a denial of service (use-after-free and system crash) or possibly gain privileges via a crafted application that leverages an improperly managed reference counter.

Project: net
File: ping.c

static int ping_check_bind_addr(struct sock *sk, struct inet_sock *isk,
				struct sockaddr *uaddr, int addr_len) {
	struct net *net = sock_net(sk);
	if (sk->sk_family == AF_INET) {
		struct sockaddr_in *addr = (struct sockaddr_in *) uaddr;
		int chk_addr_ret;

		if (addr_len < sizeof(*addr))
			return -EINVAL;

		pr_debug("ping_check_bind_addr(sk=%p,addr=%pI4,port=%d)\n",
			 sk, &addr->sin_addr.s_addr, ntohs(addr->sin_port));

		chk_addr_ret = inet_addr_type(net, addr->sin_addr.s_addr);

		if (addr->sin_addr.s_addr == htonl(INADDR_ANY))
			chk_addr_ret = RTN_LOCAL;

		if ((sysctl_ip_nonlocal_bind == 0 &&
		    isk->freebind == 0 && isk->transparent == 0 &&
		     chk_addr_ret != RTN_LOCAL) ||
		    chk_addr_ret == RTN_MULTICAST ||
		    chk_addr_ret == RTN_BROADCAST)
			return -EADDRNOTAVAIL;

#if IS_ENABLED(CONFIG_IPV6)
	} else if (sk->sk_family == AF_INET6) {
		struct sockaddr_in6 *addr = (struct sockaddr_in6 *) uaddr;
		int addr_type, scoped, has_addr;
		struct net_device *dev = NULL;

		if (addr_len < sizeof(*addr))
			return -EINVAL;

		if (addr->sin6_family != AF_INET6)
			return -EINVAL;

		pr_debug("ping_check_bind_addr(sk=%p,addr=%pI6c,port=%d)\n",
			 sk, addr->sin6_addr.s6_addr, ntohs(addr->sin6_port));

		addr_type = ipv6_addr_type(&addr->sin6_addr);
		scoped = __ipv6_addr_needs_scope_id(addr_type);
		if ((addr_type != IPV6_ADDR_ANY &&
		     !(addr_type & IPV6_ADDR_UNICAST)) ||
		    (scoped && !addr->sin6_scope_id))
			return -EINVAL;

		rcu_read_lock();
		if (addr->sin6_scope_id) {
			dev = dev_get_by_index_rcu(net, addr->sin6_scope_id);
			if (!dev) {
				rcu_read_unlock();
				return -ENODEV;
			}
		}
		has_addr = pingv6_ops.ipv6_chk_addr(net, &addr->sin6_addr, dev,
						    scoped);
		rcu_read_unlock();

		if (!(isk->freebind || isk->transparent || has_addr ||
		      addr_type == IPV6_ADDR_ANY))
			return -EADDRNOTAVAIL;

		if (scoped)
			sk->sk_bound_dev_if = addr->sin6_scope_id;
#endif
	} else {
		return -EAFNOSUPPORT;
	}
	return 0;
}

Project: net
File: ping.c

int ping_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
		 size_t len, int noblock, int flags, int *addr_len)
{
	struct inet_sock *isk = inet_sk(sk);
	int family = sk->sk_family;
	struct sk_buff *skb;
	int copied, err;

	pr_debug("ping_recvmsg(sk=%p,sk->num=%u)\n", isk, isk->inet_num);

	err = -EOPNOTSUPP;
	if (flags & MSG_OOB)
		goto out;

	if (flags & MSG_ERRQUEUE) {
		if (family == AF_INET) {
			return ip_recv_error(sk, msg, len, addr_len);
#if IS_ENABLED(CONFIG_IPV6)
		} else if (family == AF_INET6) {
			return pingv6_ops.ipv6_recv_error(sk, msg, len,
							  addr_len);
#endif
		}
	}

	skb = skb_recv_datagram(sk, flags, noblock, &err);
	if (!skb)
		goto out;

	copied = skb->len;
	if (copied > len) {
		msg->msg_flags |= MSG_TRUNC;
		copied = len;
	}

	/* Don't bother checking the checksum */
	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
	if (err)
		goto done;

	sock_recv_timestamp(msg, sk, skb);

	/* Copy the address and add cmsg data. */
	if (family == AF_INET) {
		DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);

		if (sin) {
			sin->sin_family = AF_INET;
			sin->sin_port = 0 /* skb->h.uh->source */;
			sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
			memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
			*addr_len = sizeof(*sin);
		}

		if (isk->cmsg_flags)
			ip_cmsg_recv(msg, skb);

#if IS_ENABLED(CONFIG_IPV6)
	} else if (family == AF_INET6) {
		struct ipv6_pinfo *np = inet6_sk(sk);
		struct ipv6hdr *ip6 = ipv6_hdr(skb);
		DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);

		if (sin6) {
			sin6->sin6_family = AF_INET6;
			sin6->sin6_port = 0;
			sin6->sin6_addr = ip6->saddr;
			sin6->sin6_flowinfo = 0;
			if (np->sndflow)
				sin6->sin6_flowinfo = ip6_flowinfo(ip6);
			sin6->sin6_scope_id =
				ipv6_iface_scope_id(&sin6->sin6_addr,
						    IP6CB(skb)->iif);
			*addr_len = sizeof(*sin6);
		}

		if (inet6_sk(sk)->rxopt.all)
			pingv6_ops.ip6_datagram_recv_common_ctl(sk, msg, skb);
		if (skb->protocol == htons(ETH_P_IPV6) &&
		    inet6_sk(sk)->rxopt.all)
			pingv6_ops.ip6_datagram_recv_specific_ctl(sk, msg, skb);
		else if (skb->protocol == htons(ETH_P_IP) && isk->cmsg_flags)
			ip_cmsg_recv(msg, skb);
#endif
	} else {
		BUG();
	}

	err = copied;

done:
	skb_free_datagram(sk, skb);
out:
	pr_debug("ping_recvmsg -> %d\n", err);
	return err;
}

Project: net
File: ping.c

int ping_init_sock(struct sock *sk)
{
	struct net *net = sock_net(sk);
	kgid_t group = current_egid();
	struct group_info *group_info;
	int i, j, count;
	kgid_t low, high;
	int ret = 0;

	inet_get_ping_group_range_net(net, &low, &high);
	if (gid_lte(low, group) && gid_lte(group, high))
		return 0;

	group_info = get_current_groups();
	count = group_info->ngroups;
	for (i = 0; i < group_info->nblocks; i++) {
		int cp_count = min_t(int, NGROUPS_PER_BLOCK, count);
		for (j = 0; j < cp_count; j++) {
			kgid_t gid = group_info->blocks[i][j];
			if (gid_lte(low, gid) && gid_lte(gid, high))
				goto out_release_group;
		}

		count -= cp_count;
	}

	ret = -EACCES;

out_release_group:
	put_group_info(group_info);
	return ret;
}

Project: net
File: ping.c

static int ping_v4_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
			   size_t len)
{
	struct net *net = sock_net(sk);
	struct flowi4 fl4;
	struct inet_sock *inet = inet_sk(sk);
	struct ipcm_cookie ipc;
	struct icmphdr user_icmph;
	struct pingfakehdr pfh;
	struct rtable *rt = NULL;
	struct ip_options_data opt_copy;
	int free = 0;
	__be32 saddr, daddr, faddr;
	u8  tos;
	int err;

	pr_debug("ping_v4_sendmsg(sk=%p,sk->num=%u)\n", inet, inet->inet_num);

	err = ping_common_sendmsg(AF_INET, msg, len, &user_icmph,
				  sizeof(user_icmph));
	if (err)
		return err;

	/*
	 *	Get and verify the address.
	 */

	if (msg->msg_name) {
		DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
		if (msg->msg_namelen < sizeof(*usin))
			return -EINVAL;
		if (usin->sin_family != AF_INET)
			return -EINVAL;
		daddr = usin->sin_addr.s_addr;
		/* no remote port */
	} else {
		if (sk->sk_state != TCP_ESTABLISHED)
			return -EDESTADDRREQ;
		daddr = inet->inet_daddr;
		/* no remote port */
	}

	ipc.addr = inet->inet_saddr;
	ipc.opt = NULL;
	ipc.oif = sk->sk_bound_dev_if;
	ipc.tx_flags = 0;
	ipc.ttl = 0;
	ipc.tos = -1;

	sock_tx_timestamp(sk, &ipc.tx_flags);

	if (msg->msg_controllen) {
		err = ip_cmsg_send(sock_net(sk), msg, &ipc, false);
		if (err)
			return err;
		if (ipc.opt)
			free = 1;
	}
	if (!ipc.opt) {
		struct ip_options_rcu *inet_opt;

		rcu_read_lock();
		inet_opt = rcu_dereference(inet->inet_opt);
		if (inet_opt) {
			memcpy(&opt_copy, inet_opt,
			       sizeof(*inet_opt) + inet_opt->opt.optlen);
			ipc.opt = &opt_copy.opt;
		}
		rcu_read_unlock();
	}

	saddr = ipc.addr;
	ipc.addr = faddr = daddr;

	if (ipc.opt && ipc.opt->opt.srr) {
		if (!daddr)
			return -EINVAL;
		faddr = ipc.opt->opt.faddr;
	}
	tos = get_rttos(&ipc, inet);
	if (sock_flag(sk, SOCK_LOCALROUTE) ||
	    (msg->msg_flags & MSG_DONTROUTE) ||
	    (ipc.opt && ipc.opt->opt.is_strictroute)) {
		tos |= RTO_ONLINK;
	}

	if (ipv4_is_multicast(daddr)) {
		if (!ipc.oif)
			ipc.oif = inet->mc_index;
		if (!saddr)
			saddr = inet->mc_addr;
	} else if (!ipc.oif)
		ipc.oif = inet->uc_index;

	flowi4_init_output(&fl4, ipc.oif, sk->sk_mark, tos,
			   RT_SCOPE_UNIVERSE, sk->sk_protocol,
			   inet_sk_flowi_flags(sk), faddr, saddr, 0, 0);

	security_sk_classify_flow(sk, flowi4_to_flowi(&fl4));
	rt = ip_route_output_flow(net, &fl4, sk);
	if (IS_ERR(rt)) {
		err = PTR_ERR(rt);
		rt = NULL;
		if (err == -ENETUNREACH)
			IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
		goto out;
	}

	err = -EACCES;
	if ((rt->rt_flags & RTCF_BROADCAST) &&
	    !sock_flag(sk, SOCK_BROADCAST))
		goto out;

	if (msg->msg_flags & MSG_CONFIRM)
		goto do_confirm;
back_from_confirm:

	if (!ipc.addr)
		ipc.addr = fl4.daddr;

	lock_sock(sk);

	pfh.icmph.type = user_icmph.type; /* already checked */
	pfh.icmph.code = user_icmph.code; /* ditto */
	pfh.icmph.checksum = 0;
	pfh.icmph.un.echo.id = inet->inet_sport;
	pfh.icmph.un.echo.sequence = user_icmph.un.echo.sequence;
	pfh.iov = msg->msg_iov;
	pfh.wcheck = 0;
	pfh.family = AF_INET;

	err = ip_append_data(sk, &fl4, ping_getfrag, &pfh, len,
			0, &ipc, &rt, msg->msg_flags);
	if (err)
		ip_flush_pending_frames(sk);
	else
		err = ping_v4_push_pending_frames(sk, &pfh, &fl4);
	release_sock(sk);

out:
	ip_rt_put(rt);
	if (free)
		kfree(ipc.opt);
	if (!err) {
		icmp_out_count(sock_net(sk), user_icmph.type);
		return len;
	}
	return err;

do_confirm:
	dst_confirm(&rt->dst);
	if (!(msg->msg_flags & MSG_PROBE) || len)
		goto back_from_confirm;
	err = 0;
	goto out;
}