From: Zihan Xi <zihanx@nebusec.ai> mainline inclusion from mainline-v7.2-rc7 commit 1a35da325cac4d5bcad76a2aa943408a6f1d9000 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18207 CVE: CVE-2026-74666 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- packet_set_ring() updates the RX ring state under sk_receive_queue.lock, but used to publish the tpacket receive mode through po->prot_hook.func after releasing that lock. packet_poll() and packet_recvmsg() can then run the pressure clearing path after the ring has been cleared while still seeing tpacket_rcv, causing __packet_rcv_has_room() to dereference stale or NULL ring storage. Move the existing receive hook assignment into the same sk_receive_queue.lock section as the ring state update. Keep the assignment otherwise unchanged, including on TX ring reconfiguration, to avoid adding behavior changes that are not required for the fix. Serialize packet_recvmsg() pressure clearing with the same queue lock only after PACKET_SOCK_PRESSURE has been observed. If the flag is clear and the socket has moved away from tpacket_rcv, packet_set_ring() has already detached the socket and waited for synchronize_net(), so no new packet input can set the flag again. packet_poll() already holds sk_receive_queue.lock, so it uses the new unlocked helper directly. Fixes: 2ccdbaa6d55b ("packet: rollover lock contention avoidance") Cc: stable@vger.kernel.org Reported-by: Vega <vega@nebusec.ai> Assisted-by: Codex:gpt-5.4 Signed-off-by: Zihan Xi <zihanx@nebusec.ai> Link: https://patch.msgid.link/f90b5688311fa278d1361ea8c6be0bf25967d591.1785247446... Signed-off-by: Paolo Abeni <pabeni@redhat.com> Conflicts: net/packet/af_packet.c [Context differences are due to the following patches not being merged: 9bb6cd652454 ("net/packet: introduce packet_rcv_try_clear_pressure() helper") 791a3e9f1a86 ("net/packet: convert po->pressure to an atomic flag")] Signed-off-by: JiangJieHua <jiangjiehua1@huawei.com> --- net/packet/af_packet.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index f8f8728cff536..ae1e16d2a9d5d 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -4431,14 +4431,14 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u, rb->frame_max = (req->tp_frame_nr - 1); rb->head = 0; rb->frame_size = req->tp_frame_size; + po->prot_hook.func = (po->rx_ring.pg_vec) ? + tpacket_rcv : packet_rcv; spin_unlock_bh(&rb_queue->lock); swap(rb->pg_vec_order, order); swap(rb->pg_vec_len, req->tp_block_nr); rb->pg_vec_pages = req->tp_block_size/PAGE_SIZE; - po->prot_hook.func = (po->rx_ring.pg_vec) ? - tpacket_rcv : packet_rcv; skb_queue_purge(rb_queue); if (atomic_long_read(&po->mapped)) pr_err("packet_mmap: vma is busy: %ld\n", -- 2.33.8