From: Haoze Xie br_pass_frame_up() rewrites skb->dev from the ingress port to the bridge master before queueing bridge LOCAL_IN packets. NFQUEUE only holds references on state.in/out and bridge physdevs, so a queued bridge packet can retain a freed bridge master in skb->dev until reinjection. When the verdict is reinjected later, br_netif_receive_skb() re-enters the receive path with skb->dev still pointing at the freed bridge master, triggering a use-after-free. Store skb->dev in the queue entry, hold a reference on it for the queue lifetime, and use the saved device when dropping queued packets during NETDEV_DOWN handling. Fixes: ac2863445686 ("netfilter: bridge: add nf_afinfo to enable queuing to userspace") Cc: stable@kernel.org Reported-by: Yuan Tan Reported-by: Yifan Wu Reported-by: Juefei Pu Reported-by: Xin Liu Signed-off-by: Haoze Xie Signed-off-by: Ren Wei --- v2: - move skb->dev refcounting into the generic nf_queue lifetime handling - keep the saved-device check in dev_cmp() - v1 Link: https://lore.kernel.org/all/ca7ee343bbcb44905e1f5b853df2f3a5b7d40548.1778493188.git.royenheart@gmail.com --- include/net/netfilter/nf_queue.h | 1 + net/netfilter/nf_queue.c | 4 +++- net/netfilter/nfnetlink_queue.c | 2 ++ 3 files changed, 6 insertions(+), 1 deletion(-) diff --git a/include/net/netfilter/nf_queue.h b/include/net/netfilter/nf_queue.h index d17035d14d96..3978c3174cdb 100644 --- a/include/net/netfilter/nf_queue.h +++ b/include/net/netfilter/nf_queue.h @@ -14,6 +14,7 @@ struct nf_queue_entry { struct list_head list; struct rhash_head hash_node; struct sk_buff *skb; + struct net_device *skb_dev; unsigned int id; unsigned int hook_index; /* index in hook_entries->hook[] */ #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c index a6c81c04b3a5..57b450024a99 100644 --- a/net/netfilter/nf_queue.c +++ b/net/netfilter/nf_queue.c @@ -61,6 +61,7 @@ static void nf_queue_entry_release_refs(struct nf_queue_entry *entry) struct nf_hook_state *state = &entry->state; /* Release those devices we held, or Alexey will kill me. */ + dev_put(entry->skb_dev); dev_put(state->in); dev_put(state->out); if (state->sk) @@ -102,6 +103,7 @@ bool nf_queue_entry_get_refs(struct nf_queue_entry *entry) if (state->sk && !refcount_inc_not_zero(&state->sk->sk_refcnt)) return false; + dev_hold(entry->skb_dev); dev_hold(state->in); dev_hold(state->out); @@ -202,11 +204,11 @@ static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state, *entry = (struct nf_queue_entry) { .skb = skb, + .skb_dev = skb->dev, .state = *state, .hook_index = index, .size = sizeof(*entry) + route_key_size, }; - __nf_queue_entry_init_physdevs(entry); if (!nf_queue_entry_get_refs(entry)) { diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c index 58304fd1f70f..984a0eb9e149 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -1212,6 +1212,8 @@ dev_cmp(struct nf_queue_entry *entry, unsigned long ifindex) if (physinif == ifindex || physoutif == ifindex) return 1; #endif + if (entry->skb_dev && entry->skb_dev->ifindex == ifindex) + return 1; if (entry->state.in) if (entry->state.in->ifindex == ifindex) return 1; -- 2.53.0