2019-07-01 16:42:21

by Matteo Croce

Subject: [PATCH net] 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 <[email protected]>
---
net/ipv4/devinet.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index c6bd0f7a020a..f40ccdcf4cfe 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 IPv6 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) &&
--
2.21.0

2019-07-01 16:42:26

by Joe Perches

Subject: Re: [PATCH net] ipv4: don't set IPv6 only flags to IPv4 addresses

On Mon, 2019-07-01 at 18:08 +0200, Matteo Croce wrote:
> Avoid the situation where an IPV6 only flag is applied to an IPv4 address:
[]
> diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
[]
> @@ -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 IPv6 addresses */

umm, IPv4 addresses?

2019-07-01 16:44:56

by Matteo Croce

Subject: Re: [PATCH net] ipv4: don't set IPv6 only flags to IPv4 addresses

On Mon, Jul 1, 2019 at 6:10 PM Joe Perches <[email protected]> wrote:
>
> On Mon, 2019-07-01 at 18:08 +0200, Matteo Croce wrote:
> > Avoid the situation where an IPV6 only flag is applied to an IPv4 address:
> []
> > diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
> []
> > @@ -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 IPv6 addresses */
>
> umm, IPv4 addresses?
>
>

Ouch, right.

/* Don't set IPv6 only flags to IPv4 addresses */

Can this be edidet on patchwork instead of spamming with a v2?

--
Matteo Croce
per aspera ad upstream

2019-07-01 18:25:09

by David Miller

Subject: Re: [PATCH net] ipv4: don't set IPv6 only flags to IPv4 addresses

From: Matteo Croce <[email protected]>
Date: Mon, 1 Jul 2019 18:13:32 +0200

> Can this be edidet on patchwork instead of spamming with a v2?

"Spamming"?

It's never spamming, resends make my life SO much easier.