diff options
| author | Florian Westphal <fw@strlen.de> | 2022-03-01 00:46:19 +0100 |
|---|---|---|
| committer | Florian Westphal <fw@strlen.de> | 2022-03-01 11:51:15 +0100 |
| commit | 3b836da4081fa585cf6c392f62557496f2cb0efe (patch) | |
| tree | f2dcb351b8b08fd020d00958cb10ac9c50c91804 /net | |
| parent | c3873070247d9e3c7a6b0cf9bf9b45e8018427b1 (diff) | |
netfilter: nf_queue: handle socket prefetch
In case someone combines bpf socket assign and nf_queue, then we will
queue an skb who references a struct sock that did not have its
reference count incremented.
As we leave rcu protection, there is no guarantee that skb->sk is still
valid.
For refcount-less skb->sk case, try to increment the reference count
and then override the destructor.
In case of failure we have two choices: orphan the skb and 'delete'
preselect or let nf_queue() drop the packet.
Do the latter, it should not happen during normal operation.
Fixes: cf7fbe660f2d ("bpf: Add socket assign support")
Acked-by: Joe Stringer <joe@cilium.io>
Signed-off-by: Florian Westphal <fw@strlen.de>
Diffstat (limited to 'net')
| -rw-r--r-- | net/netfilter/nf_queue.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c index e39549c55945..63d1516816b1 100644 --- a/net/netfilter/nf_queue.c +++ b/net/netfilter/nf_queue.c @@ -180,6 +180,18 @@ static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state, break; } + if (skb_sk_is_prefetched(skb)) { + struct sock *sk = skb->sk; + + if (!sk_is_refcounted(sk)) { + if (!refcount_inc_not_zero(&sk->sk_refcnt)) + return -ENOTCONN; + + /* drop refcount on skb_orphan */ + skb->destructor = sock_edemux; + } + } + entry = kmalloc(sizeof(*entry) + route_key_size, GFP_ATOMIC); if (!entry) return -ENOMEM; |