diff options
| author | Jakub Kicinski <kuba@kernel.org> | 2026-06-17 16:03:57 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-06-17 16:03:58 -0700 |
| commit | 0e80602c026b98ec9f775f8a6a4eaea577733d6b (patch) | |
| tree | dc2aa5bfc1ee4cdec9a45fd43541d7ecf4aecb85 /include | |
| parent | e586644d0a89b6c63b77ae717f19d70181faee76 (diff) | |
| parent | 095515d89b19b6cc19dfcdc846f97403ed1ebce3 (diff) | |
Merge branch 'net-require-cap_net_admin-in-the-device-netns-for-tunnel-changelink'
Maoyi Xie says:
====================
net: require CAP_NET_ADMIN in the device netns for tunnel changelink
A tunnel changelink() operates on at most two netns, dev_net(dev) and
the tunnel link netns t->net. They differ once the device is created in
or moved to a netns other than the one the request runs in. The rtnl
changelink path checks CAP_NET_ADMIN only against dev_net(dev), so a
caller privileged there but not in the link netns can rewrite a tunnel
that lives in the link netns. Commit 8b484efd5cb4 ("ip6: vti: Use
ip6_tnl.net in vti6_siocdevprivate().") added the same check on the
ioctl path. This series adds it on the RTM_NEWLINK path.
Each changelink is gated at the top of the op, before any attribute is
parsed, because the per-type parsers can update live tunnel fields first
(for example ipgre_netlink_parms() sets t->collect_md). The check is
skipped when the link netns is dev_net(dev), where the rtnl path already
checked the cap.
The check goes through a new helper, rtnl_dev_link_net_capable(), added
in patch 1 next to rtnl_get_net_ns_capable() in net/core/rtnetlink.c.
Tested on net/main. For every tunnel type in the series a migrated
fake-root changelink is rejected with EPERM. For vti6 SIOCGETTUNNEL
confirms the link netns hash is left unchanged. Legit non-migrated
changelinks still succeed.
v5: https://lore.kernel.org/20260611062814.2528793-1-maoyixie.tju@gmail.com
v4: https://lore.kernel.org/20260609163110.1717419-1-maoyixie.tju@gmail.com
v3: https://lore.kernel.org/20260604125055.3254652-1-maoyixie.tju@gmail.com
v2: https://lore.kernel.org/20260601034148.1272080-1-maoyixie.tju@gmail.com
v1: https://lore.kernel.org/20260527070824.2677331-1-maoyixie.tju@gmail.com
====================
Link: https://patch.msgid.link/20260612085941.3158249-1-maoyixie.tju@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/net/rtnetlink.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h index ec65a8cebb99..2bff41aacc98 100644 --- a/include/net/rtnetlink.h +++ b/include/net/rtnetlink.h @@ -256,6 +256,8 @@ int rtnl_configure_link(struct net_device *dev, const struct ifinfomsg *ifm, int rtnl_nla_parse_ifinfomsg(struct nlattr **tb, const struct nlattr *nla_peer, struct netlink_ext_ack *exterr); struct net *rtnl_get_net_ns_capable(struct sock *sk, int netnsid); +bool rtnl_dev_link_net_capable(const struct net_device *dev, + const struct net *link_net); #define MODULE_ALIAS_RTNL_LINK(kind) MODULE_ALIAS("rtnl-link-" kind) |