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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>
alistair/sunxi64-5.4-dsi
Matteo Croce 2019-07-01 19:01:55 +02:00 committed by David S. Miller
parent 88405680ec
commit 2e60546368
1 changed files with 8 additions and 0 deletions
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8
net/ipv4/devinet.c
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@ -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) &&