Description
In the Linux kernel, the following vulnerability has been resolved: ip6: vti: Use ip6_tnl.net in vti6_siocdevprivate(). After patch 1/2 in this series, vti6_update() unlinks and relinks the tunnel through t->net. vti6_siocdevprivate() still uses dev_net(dev) for the collision lookup. For a tunnel moved through IFLA_NET_NS_FD, dev_net(dev) is the new netns, not t->net. SIOCCHGTUNNEL on a migrated tunnel then runs: net = dev_net(dev) /* migrated netns */ t = vti6_locate(net, &p1, false) /* misses target in t->net */ ... t = netdev_priv(dev) vti6_update(t, &p1, false) /* mutates t->net's hash */ A caller in the migrated netns picks params that match a tunnel in the creation netns. The lookup in dev_net(dev) finds nothing. vti6_update() prepends the migrated tunnel at the head of the creation netns hash bucket for those params. Later lookups in the creation netns resolve to the migrated device. xfrm receive delivers the matched packets through a device the caller controls. Reachable from an unprivileged user namespace (unshare --user --map-root-user --net). Cross tenant scope on container hosts. Switch the SIOCCHGTUNNEL path on a non fallback device to use t->net for the lookup. The lookup now matches the netns vti6_update() operates on. Also add ns_capable(self->net->user_ns, CAP_NET_ADMIN) before the lookup. The check at the top of the case is against dev_net(dev)->user_ns, which after migration is the attacker's netns. A caller there can pick params absent from self->net, the lookup returns NULL, t becomes self, and vti6_update() inserts the device into the creation netns hash. The new check requires CAP_NET_ADMIN in the creation netns user_ns too. SIOCADDTUNNEL and SIOCCHGTUNNEL on the fallback device keep dev_net(dev), which equals init_net there.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
61220ab349485d911083d0b7990ccd3db6c63297 to < 94ff740a7f9ef5c010784a325dca00cbf228f941affected61220ab349485d911083d0b7990ccd3db6c63297 to < df42ac708acc3399bbb6dc5ca16e0540adda7bbfaffected61220ab349485d911083d0b7990ccd3db6c63297 to < 44d2ff7d2178503b93151140a45dfa2ad49c9906affected61220ab349485d911083d0b7990ccd3db6c63297 to < 1acfb7d9c6fc7e209ed7789392697e97e03edd33affected61220ab349485d911083d0b7990ccd3db6c63297 to < d2236348414bdd6558385f35aa7fdc9bf5634011affected61220ab349485d911083d0b7990ccd3db6c63297 to < 853f6ea482dfcd3404bbef458ab4d68364eed838affected61220ab349485d911083d0b7990ccd3db6c63297 to < 596f6354c96a891e58c04a09cbfb7b0d1ec00dabaffected61220ab349485d911083d0b7990ccd3db6c63297 to < 8b484efd5cb4eeef9021a661e198edc5349dacf6affected
Linux Linux
Default version status: affected
3.15affected0 to < 3.15unaffected5.10.259 to ≤ 5.10.*unaffected5.15.210 to ≤ 5.15.*unaffected6.1.176 to ≤ 6.1.*unaffected6.6.143 to ≤ 6.6.*unaffected6.12.93 to ≤ 6.12.*unaffected6.18.35 to ≤ 6.18.*unaffected7.0.12 to ≤ 7.0.*unaffected7.1 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/94ff740a7f9ef5c010784a325dca00cbf228f941 ↗
- https://git.kernel.org/stable/c/df42ac708acc3399bbb6dc5ca16e0540adda7bbf ↗
- https://git.kernel.org/stable/c/44d2ff7d2178503b93151140a45dfa2ad49c9906 ↗
- https://git.kernel.org/stable/c/1acfb7d9c6fc7e209ed7789392697e97e03edd33 ↗
- https://git.kernel.org/stable/c/d2236348414bdd6558385f35aa7fdc9bf5634011 ↗
- https://git.kernel.org/stable/c/853f6ea482dfcd3404bbef458ab4d68364eed838 ↗
- https://git.kernel.org/stable/c/596f6354c96a891e58c04a09cbfb7b0d1ec00dab ↗
- https://git.kernel.org/stable/c/8b484efd5cb4eeef9021a661e198edc5349dacf6 ↗