From: Matteo Croce mcroce@redhat.com
[ 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 --- net/ipv4/devinet.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- 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, @@ -472,6 +477,9 @@ static int __inet_insert_ifa(struct in_i 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) &&