net: ipv4: devinet: Fix crash when add/del multicast IP with autojoin (690cc863) · Commits · 戴 / test

When CONFIG_IP_MULTICAST is not set and multicast ip is added to the device with autojoin flag or when multicast ip is deleted kernel will crash. steps to reproduce: ip addr add 224.0.0.0/32 dev eth0 ip addr del 224.0.0.0/32 dev eth0 or ip addr add 224.0.0.0/32 dev eth0 autojoin Unable to handle kernel NULL pointer dereference at virtual address 0000000000000088 pc : _raw_write_lock_irqsave+0x1e0/0x2ac lr : lock_sock_nested+0x1c/0x60 Call trace: _raw_write_lock_irqsave+0x1e0/0x2ac lock_sock_nested+0x1c/0x60 ip_mc_config.isra.28+0x50/0xe0 inet_rtm_deladdr+0x1a8/0x1f0 rtnetlink_rcv_msg+0x120/0x350 netlink_rcv_skb+0x58/0x120 rtnetlink_rcv+0x14/0x20 netlink_unicast+0x1b8/0x270 netlink_sendmsg+0x1a0/0x3b0 ____sys_sendmsg+0x248/0x290 ___sys_sendmsg+0x80/0xc0 __sys_sendmsg+0x68/0xc0 __arm64_sys_sendmsg+0x20/0x30 el0_svc_common.constprop.2+0x88/0x150 do_el0_svc+0x20/0x80 el0_sync_handler+0x118/0x190 el0_sync+0x140/0x180 Fixes: ("multicast: Extend ip address command to enable multicast group join/leave on") Signed-off-by:

Taras Chornyi <taras.chornyi@plvision.eu> Signed-off-by:

Vadym Kochan <vadym.kochan@plvision.eu> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/ipv4/devinet.c

+9 −4

Original line number	Diff line number	Diff line
		@@ -614,12 +614,15 @@ struct in_ifaddr inet_ifa_byprefix(struct in_device in_dev, __be32 prefix,
		return NULL;
		}

		static int ip_mc_config(struct sock sk, bool join, const struct in_ifaddr ifa)
		static int ip_mc_autojoin_config(struct net *net, bool join,
		const struct in_ifaddr *ifa)
		{
		#if defined(CONFIG_IP_MULTICAST)
		struct ip_mreqn mreq = {
		.imr_multiaddr.s_addr = ifa->ifa_address,
		.imr_ifindex = ifa->ifa_dev->dev->ifindex,
		};
		struct sock *sk = net->ipv4.mc_autojoin_sk;
		int ret;

		ASSERT_RTNL();
		@@ -632,6 +635,9 @@ static int ip_mc_config(struct sock sk, bool join, const struct in_ifaddr ifa)
		release_sock(sk);

		return ret;
		#else
		return -EOPNOTSUPP;
		#endif
		}

		static int inet_rtm_deladdr(struct sk_buff skb, struct nlmsghdr nlh,
		@@ -675,7 +681,7 @@ static int inet_rtm_deladdr(struct sk_buff skb, struct nlmsghdr nlh,
		continue;

		if (ipv4_is_multicast(ifa->ifa_address))
		ip_mc_config(net->ipv4.mc_autojoin_sk, false, ifa);
		ip_mc_autojoin_config(net, false, ifa);
		__inet_del_ifa(in_dev, ifap, 1, nlh, NETLINK_CB(skb).portid);
		return 0;
		}
		@@ -940,8 +946,7 @@ static int inet_rtm_newaddr(struct sk_buff skb, struct nlmsghdr nlh,
		*/
		set_ifa_lifetime(ifa, valid_lft, prefered_lft);
		if (ifa->ifa_flags & IFA_F_MCAUTOJOIN) {
		int ret = ip_mc_config(net->ipv4.mc_autojoin_sk,
		true, ifa);
		int ret = ip_mc_autojoin_config(net, true, ifa);

		if (ret < 0) {
		inet_free_ifa(ifa);

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