diff options
| author | Kevin Cernekee <cernekee@chromium.org> | 2017-12-05 15:42:41 -0800 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2017-12-06 09:01:18 +0100 |
| commit | 916a27901de01446bcf57ecca4783f6cff493309 (patch) | |
| tree | 4c799eda5882355010e6fca6bfb478210b8012bb /net/netfilter | |
| parent | 6ab405114b0b229151ef06f4e31c7834dd09d0c0 (diff) | |
netfilter: xt_osf: 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, xt_osf_fingers 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:
vpnns -- nfnl_osf -f /tmp/pf.os
vpnns -- nfnl_osf -f /tmp/pf.os -d
These non-root operations successfully modify the systemwide OS
fingerprint list. Add new capable() checks so that they can't.
Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter')
| -rw-r--r-- | net/netfilter/xt_osf.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/net/netfilter/xt_osf.c b/net/netfilter/xt_osf.c index 36e14b1f061d..a34f314a8c23 100644 --- a/net/netfilter/xt_osf.c +++ b/net/netfilter/xt_osf.c @@ -19,6 +19,7 @@ #include <linux/module.h> #include <linux/kernel.h> +#include <linux/capability.h> #include <linux/if.h> #include <linux/inetdevice.h> #include <linux/ip.h> @@ -70,6 +71,9 @@ static int xt_osf_add_callback(struct net *net, struct sock *ctnl, struct xt_osf_finger *kf = NULL, *sf; int err = 0; + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + if (!osf_attrs[OSF_ATTR_FINGER]) return -EINVAL; @@ -115,6 +119,9 @@ static int xt_osf_remove_callback(struct net *net, struct sock *ctnl, struct xt_osf_finger *sf; int err = -ENOENT; + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + if (!osf_attrs[OSF_ATTR_FINGER]) return -EINVAL; |