[PATCH nf-next v3 5/7] nf_register_net_hook: Only allow sane values

[Aaron Conole]

This commit adds an upfront check for sane values to be passed when
registering a netfilter hook.  This will be used in a future patch for a
simplified hook list traversal.

Signed-off-by: Aaron Conole <acon...@bytheb.org>
---
 net/netfilter/core.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/netfilter/core.c b/net/netfilter/core.c
index c8faf81..67b7428 100644
--- a/net/netfilter/core.c
+++ b/net/netfilter/core.c
@@ -89,6 +89,11 @@ int nf_register_net_hook(struct net *net, const struct 
nf_hook_ops *reg)
        struct nf_hook_entry *entry;
        struct nf_hook_ops *elem;
 
+       if (reg->pf == NFPROTO_NETDEV &&
+           (reg->hooknum != NF_NETDEV_INGRESS ||
+            !reg->dev || dev_net(reg->dev) != net))
+               return -EINVAL;
+
        entry = kmalloc(sizeof(*entry), GFP_KERNEL);
        if (!entry)
                return -ENOMEM;
-- 
2.7.4