| Message ID | 20190701170155.1967-1-mcroce@redhat.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net,v2] ipv4: don't set IPv6 only flags to IPv4 addresses | expand |
On 7/1/19 11:01 AM, Matteo Croce wrote: > 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> > --- > 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 <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) && > I guess at this point we can fail the address add, so this is the best option. rtm_to_ifaddr could set a message in extack about invalid flags - not fail the change, just warn the user that flags will be ignored. Reviewed-by: David Ahern <dsahern@gmail.com>
On 7/1/19 11:19 AM, David Ahern wrote: > I guess at this point we can fail the address add, so this is the best > option. bleh, that should be 'can not'
From: Matteo Croce <mcroce@redhat.com> Date: Mon, 1 Jul 2019 19:01:55 +0200 > 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> Applied and queued up for -stable, thanks Matteo.
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 <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) &&
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> --- net/ipv4/devinet.c | 8 ++++++++ 1 file changed, 8 insertions(+)