From: Florian Westphal fw@strlen.de
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 --- include/net/netfilter/nf_queue.h | 2 +- net/netfilter/nf_queue.c | 12 ++++++++++-- net/netfilter/nfnetlink_queue.c | 12 +++++++++--- 3 files changed, 20 insertions(+), 6 deletions(-)
--- a/include/net/netfilter/nf_queue.h +++ b/include/net/netfilter/nf_queue.h @@ -31,7 +31,7 @@ void nf_register_queue_handler(struct ne 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) --- a/net/netfilter/nf_queue.c +++ b/net/netfilter/nf_queue.c @@ -80,10 +80,13 @@ void nf_queue_entry_release_refs(struct 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 && !atomic_inc_not_zero(&state->sk->sk_refcnt)) + return false; + if (state->in) dev_hold(state->in); if (state->out) @@ -102,6 +105,7 @@ void nf_queue_entry_get_refs(struct nf_q dev_hold(physdev); } #endif + return true; } EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
@@ -148,7 +152,11 @@ static int __nf_queue(struct sk_buff *sk .size = sizeof(*entry) + afinfo->route_key_size, };
- nf_queue_entry_get_refs(entry); + if (!nf_queue_entry_get_refs(entry)) { + kfree(entry); + return -ENOTCONN; + } + skb_dst_force(skb); afinfo->saveroute(skb, entry); status = qh->outfn(entry, queuenum); --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -673,9 +673,15 @@ 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)