diff options
| author | Florian Westphal <fw@strlen.de> | 2022-02-28 06:22:22 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-03-08 19:04:07 +0100 |
| commit | 34dc4a6a7f261736ef7183868a5bddad31c7f9e3 (patch) | |
| tree | caad7ef82a3b6b94bc3ef716e8a0f1b14da48d96 | |
| parent | 6d9719ef61a99d1ed750b510d32620a6c4bb7397 (diff) | |
netfilter: nf_queue: fix possible use-after-free
commit c3873070247d9e3c7a6b0cf9bf9b45e8018427b1 upstream.
Eric Dumazet says:
The sock_hold() side seems suspect, because there is no guarantee
that sk_refcnt is not already 0.
On failure, we cannot queue the packet and need to indicate an
error. The packet will be dropped by the caller.
v2: split skb prefetch hunk into separate change
Fixes: 271b72c7fa82c ("udp: RCU handling for Unicast packets.")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | include/net/netfilter/nf_queue.h | 2 | ||||
| -rw-r--r-- | net/netfilter/nf_queue.c | 11 | ||||
| -rw-r--r-- | net/netfilter/nfnetlink_queue.c | 12 |
3 files changed, 19 insertions, 6 deletions
diff --git a/include/net/netfilter/nf_queue.h b/include/net/netfilter/nf_queue.h index a50a69f5334c..861414a62ce1 100644 --- a/include/net/netfilter/nf_queue.h +++ b/include/net/netfilter/nf_queue.h @@ -32,7 +32,7 @@ void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *q void nf_unregister_queue_handler(struct net *net); void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict); -void nf_queue_entry_get_refs(struct nf_queue_entry *entry); +bool nf_queue_entry_get_refs(struct nf_queue_entry *entry); void nf_queue_entry_release_refs(struct nf_queue_entry *entry); static inline void init_hashrandom(u32 *jhash_initval) diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c index ca0c9a9dcdc8..84c59de27882 100644 --- a/net/netfilter/nf_queue.c +++ b/net/netfilter/nf_queue.c @@ -82,10 +82,13 @@ void nf_queue_entry_release_refs(struct nf_queue_entry *entry) EXPORT_SYMBOL_GPL(nf_queue_entry_release_refs); /* Bump dev refs so they don't vanish while packet is out */ -void nf_queue_entry_get_refs(struct nf_queue_entry *entry) +bool nf_queue_entry_get_refs(struct nf_queue_entry *entry) { struct nf_hook_state *state = &entry->state; + if (state->sk && !refcount_inc_not_zero(&state->sk->sk_refcnt)) + return false; + if (state->in) dev_hold(state->in); if (state->out) @@ -104,6 +107,7 @@ void nf_queue_entry_get_refs(struct nf_queue_entry *entry) dev_hold(physdev); } #endif + return true; } EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs); @@ -195,7 +199,10 @@ static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state, .size = sizeof(*entry) + route_key_size, }; - nf_queue_entry_get_refs(entry); + if (!nf_queue_entry_get_refs(entry)) { + kfree(entry); + return -ENOTCONN; + } switch (entry->state.pf) { case AF_INET: diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c index 8955431f2ab2..a5aff2834bd6 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -716,9 +716,15 @@ static struct nf_queue_entry * nf_queue_entry_dup(struct nf_queue_entry *e) { struct nf_queue_entry *entry = kmemdup(e, e->size, GFP_ATOMIC); - if (entry) - nf_queue_entry_get_refs(entry); - return entry; + + if (!entry) + return NULL; + + if (nf_queue_entry_get_refs(entry)) + return entry; + + kfree(entry); + return NULL; } #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) |