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authorDaniel Borkmann <dborkmann@redhat.com>2013-09-05 17:48:47 +0200
committerDavid S. Miller <davem@davemloft.net>2013-09-06 14:43:48 -0400
commit5ffd5cddd4d353fe18c01b89397dcad02035bb95 (patch)
tree517e4941160237ed41c440776ac2986904fbb715 /net/netlink
parent2e032852245b3dcfe5461d7353e34eb6da095ccf (diff)
downloadlinux-5ffd5cddd4d353fe18c01b89397dcad02035bb95.tar.gz
net: netlink: filter particular protocols from analyzers
Fix finer-grained control and let only a whitelist of allowed netlink protocols pass, in our case related to networking. If later on, other subsystems decide they want to add their protocol as well to the list of allowed protocols they shall simply add it. While at it, we also need to tell what protocol is in use otherwise BPF_S_ANC_PROTOCOL can not pick it up (as it's not filled out). Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/netlink')
-rw-r--r--net/netlink/af_netlink.c30
1 files changed, 30 insertions, 0 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index a17dda1bbee..8df7f64c6db 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -168,16 +168,43 @@ int netlink_remove_tap(struct netlink_tap *nt)
}
EXPORT_SYMBOL_GPL(netlink_remove_tap);
+static bool netlink_filter_tap(const struct sk_buff *skb)
+{
+ struct sock *sk = skb->sk;
+ bool pass = false;
+
+ /* We take the more conservative approach and
+ * whitelist socket protocols that may pass.
+ */
+ switch (sk->sk_protocol) {
+ case NETLINK_ROUTE:
+ case NETLINK_USERSOCK:
+ case NETLINK_SOCK_DIAG:
+ case NETLINK_NFLOG:
+ case NETLINK_XFRM:
+ case NETLINK_FIB_LOOKUP:
+ case NETLINK_NETFILTER:
+ case NETLINK_GENERIC:
+ pass = true;
+ break;
+ }
+
+ return pass;
+}
+
static int __netlink_deliver_tap_skb(struct sk_buff *skb,
struct net_device *dev)
{
struct sk_buff *nskb;
+ struct sock *sk = skb->sk;
int ret = -ENOMEM;
dev_hold(dev);
nskb = skb_clone(skb, GFP_ATOMIC);
if (nskb) {
nskb->dev = dev;
+ nskb->protocol = htons((u16) sk->sk_protocol);
+
ret = dev_queue_xmit(nskb);
if (unlikely(ret > 0))
ret = net_xmit_errno(ret);
@@ -192,6 +219,9 @@ static void __netlink_deliver_tap(struct sk_buff *skb)
int ret;
struct netlink_tap *tmp;
+ if (!netlink_filter_tap(skb))
+ return;
+
list_for_each_entry_rcu(tmp, &netlink_tap_all, list) {
ret = __netlink_deliver_tap_skb(skb, tmp->dev);
if (unlikely(ret))