Commit 2e605463 authored Jul 01, 2019 by Matteo Croce Committed by David S. Miller Jul 01, 2019

ipv4: don't set IPv6 only flags to IPv4 addresses



Avoid the situation where an IPV6 only flag is applied to an IPv4 address:

    # ip addr add 192.0.2.1/24 dev dummy0 nodad home mngtmpaddr noprefixroute
    # ip -4 addr show dev dummy0
    2: dummy0: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
        inet 192.0.2.1/24 scope global noprefixroute dummy0
           valid_lft forever preferred_lft forever

Or worse, by sending a malicious netlink command:

    # ip -4 addr show dev dummy0
    2: dummy0: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
        inet 192.0.2.1/24 scope global nodad optimistic dadfailed home tentative mngtmpaddr noprefixroute stable-privacy dummy0
           valid_lft forever preferred_lft forever

Signed-off-by: Matteo Croce <mcroce@redhat.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 88405680

net/ipv4/devinet.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -62,6 +62,11 @@
		#include <net/net_namespace.h>
		#include <net/addrconf.h>

		#define IPV6ONLY_FLAGS \
		(IFA_F_NODAD \| IFA_F_OPTIMISTIC \| IFA_F_DADFAILED \| \
		IFA_F_HOMEADDRESS \| IFA_F_TENTATIVE \| \
		IFA_F_MANAGETEMPADDR \| IFA_F_STABLE_PRIVACY)

		static struct ipv4_devconf ipv4_devconf = {
		.data = {
		[IPV4_DEVCONF_ACCEPT_REDIRECTS - 1] = 1,
		@@ -468,6 +473,9 @@ static int __inet_insert_ifa(struct in_ifaddr ifa, struct nlmsghdr nlh,
		ifa->ifa_flags &= ~IFA_F_SECONDARY;
		last_primary = &in_dev->ifa_list;

		/* Don't set IPv6 only flags to IPv4 addresses */
		ifa->ifa_flags &= ~IPV6ONLY_FLAGS;

		for (ifap = &in_dev->ifa_list; (ifa1 = *ifap) != NULL;
		ifap = &ifa1->ifa_next) {
		if (!(ifa1->ifa_flags & IFA_F_SECONDARY) &&

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