From 2e60546368165c2449564d71f6005dda9205b5fb Mon Sep 17 00:00:00 2001 From: Matteo Croce Date: Mon, 1 Jul 2019 19:01:55 +0200 Subject: 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: 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: 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 Reviewed-by: David Ahern Signed-off-by: David S. Miller --- net/ipv4/devinet.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index c6bd0f7a020a..c5ebfa199794 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -62,6 +62,11 @@ #include #include +#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) && -- cgit v1.2.3