diff options
author | Florian Westphal <fw@strlen.de> | 2020-03-27 03:24:48 +0100 |
---|---|---|
committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2020-03-29 16:28:29 +0200 |
commit | af370ab36fcd19f04e3408c402608e7e56e6f188 (patch) | |
tree | 611e42c64973cbfbed7d42259708738b42c32964 | |
parent | 119e52e664c57d5f7c0174dc2b3a296b1e40591d (diff) | |
download | linux-af370ab36fcd19f04e3408c402608e7e56e6f188.tar.bz2 |
netfilter: nf_queue: do not release refcouts until nf_reinject is done
nf_queue is problematic when another NF_QUEUE invocation happens
from nf_reinject().
1. nf_queue is invoked, increments state->sk refcount.
2. skb is queued, waiting for verdict.
3. sk is closed/released.
3. verdict comes back, nf_reinject is called.
4. nf_reinject drops the reference -- refcount can now drop to 0
Instead of get_ref/release_ref pattern, we need to nest the get_ref calls:
get_ref
get_ref
release_ref
release_ref
So that when we invoke the next processing stage (another netfilter
or the okfn()), we hold at least one reference count on the
devices/socket.
After previous patch, it is now safe to put the entry even after okfn()
has potentially free'd the skb.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
-rw-r--r-- | net/netfilter/nf_queue.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c index 96eb72908467..aadccdd117f0 100644 --- a/net/netfilter/nf_queue.c +++ b/net/netfilter/nf_queue.c @@ -303,12 +303,10 @@ void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict) hooks = nf_hook_entries_head(net, pf, entry->state.hook); - nf_queue_entry_release_refs(entry); - i = entry->hook_index; if (WARN_ON_ONCE(!hooks || i >= hooks->num_hook_entries)) { kfree_skb(skb); - kfree(entry); + nf_queue_entry_free(entry); return; } @@ -347,6 +345,6 @@ next_hook: kfree_skb(skb); } - kfree(entry); + nf_queue_entry_free(entry); } EXPORT_SYMBOL(nf_reinject); |