FROMLIST: netfilter: nfnetlink_cthelper: Add missing permission checks
The capability check in nfnetlink_rcv() verifies that the caller
has CAP_NET_ADMIN in the namespace that "owns" the netlink socket.
However, nfnl_cthelper_list is shared by all net namespaces on the
system. An unprivileged user can create user and net namespaces
in which he holds CAP_NET_ADMIN to bypass the netlink_net_capable()
check:
$ nfct helper list
nfct v1.4.4: netlink error: Operation not permitted
$ vpnns -- nfct helper list
{
.name = ftp,
.queuenum = 0,
.l3protonum = 2,
.l4protonum = 6,
.priv_data_len = 24,
.status = enabled,
};
Add capable() checks in nfnetlink_cthelper, as this is cleaner than
trying to generalize the solution.
Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
Link: https://patchwork.kernel.org/patch/10089373/
BUG=chromium:792264
TEST=buildbots
Change-Id: I012eeeac3c8c019a95f5bebc0f0753ffdf709144
Reviewed-on: https://chromium-review.googlesource.com/809963
Commit-Ready: Kevin Cernekee <cernekee@chromium.org>
Tested-by: Kevin Cernekee <cernekee@chromium.org>
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
1 file changed
