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

[ Upstream commit 2e60546368165c2449564d71f6005dda9205b5fb ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index bffa88ecc534b9a8bd7f3c1ef28fef0def9684c3..5264510c9983947dfeb4691697d57c1d1159f9f4 100644 (file)
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -66,6 +66,11 @@
 #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,
@@ -455,6 +460,9 @@ 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) &&