6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daehyeon Ko <4ncienth@gmail.com> [ Upstream commit ad9a7da3fa39c2d616ec0dd3cf6e30531d032fe7 ] vmci_transport_recv_stream_cb() looks up sockets first by the full source and destination tuple, then by destination only in the bound table. The fallback can select a non-listening socket without checking whether the packet came from its stored peer. This was reproduced with two VMCI contexts. A RST from the context not stored in a TCP_SYN_SENT socket reset that socket after it was selected by the destination-only lookup. VMCI can process notification packets in bottom-half context when the socket is not owned by user context, or defer packets to a workqueue. Use vsock_check_source() after taking the socket lock in the bottom-half path, and recheck after lock_sock() in the workqueue path. Listening sockets continue to accept packets from any source. Reply with a RST addressed from the received packet before dropping a source that fails validation. This preserves the existing reset behavior for bound non-listening and concurrently closed sockets without directing the reset to a connected socket's stored peer. Fixes: d021c344051a ("VSOCK: Introduce VM Sockets") Reported-by: Sashiko Closes: https://lore.kernel.org/netdev/20260814121255.6B5001F000E9@smtp.kernel.org/ Cc: stable@vger.kernel.org Suggested-by: Stefano Garzarella Suggested-by: Paolo Abeni Signed-off-by: Daehyeon Ko <4ncienth@gmail.com> Reviewed-by: Vishnu Dasa Link: https://patch.msgid.link/20260826003929.966160-3-4ncienth@gmail.com Signed-off-by: Jakub Kicinski [ sashal: Replaced two calls to the unavailable vsock_check_source() helper with equivalent inline conditions. ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- Depends on <20261022162527.1685626-1-sashal@kernel.org> net/vmw_vsock/vmci_transport.c | 42 ++++++++++++++++++++++++++++++++++------- 1 file changed, 35 insertions(+), 7 deletions(-) --- a/net/vmw_vsock/vmci_transport.c +++ b/net/vmw_vsock/vmci_transport.c @@ -676,11 +676,13 @@ static int vmci_transport_recv_stream_cb struct vmci_transport_packet *pkt; struct vsock_sock *vsk; bool bh_process_pkt; + bool drop_pkt; int err; sk = NULL; err = VMCI_SUCCESS; bh_process_pkt = false; + drop_pkt = false; /* Ignore incoming packets from contexts without sockets, or resources * that aren't vsock implementations. @@ -757,17 +759,32 @@ static int vmci_transport_recv_stream_cb bh_lock_sock(sk); if (!sock_owned_by_user(sk)) { - /* The local context ID may be out of date, update it. */ - vsk->local_addr.svm_cid = dst.svm_cid; - - if (sk->sk_state == TCP_ESTABLISHED) - vmci_trans(vsk)->notify_ops->handle_notify_pkt( - sk, pkt, true, &dst, &src, - &bh_process_pkt); + if (sk->sk_state != TCP_LISTEN && + (vsk->transport != &vmci_transport || + src.svm_port != vsk->remote_addr.svm_port || + (src.svm_cid != vsk->remote_addr.svm_cid && + vmci_transport.get_local_cid() != VMADDR_CID_LOCAL))) { + drop_pkt = true; + err = VMCI_ERROR_NO_ACCESS; + } else { + /* The local context ID may be out of date, update it. */ + vsk->local_addr.svm_cid = dst.svm_cid; + + if (sk->sk_state == TCP_ESTABLISHED) + vmci_trans(vsk)->notify_ops->handle_notify_pkt(sk, pkt, true, + &dst, &src, + &bh_process_pkt); + } } bh_unlock_sock(sk); + if (drop_pkt) { + if (vmci_transport_send_reset_bh(&dst, &src, pkt) < 0) + pr_err("unable to send reset\n"); + goto out; + } + if (!bh_process_pkt) { struct vmci_transport_recv_pkt_info *recv_pkt_info; @@ -892,6 +909,7 @@ static void vmci_transport_recv_pkt_work { struct vmci_transport_recv_pkt_info *recv_pkt_info; struct vmci_transport_packet *pkt; + struct sockaddr_vm src; struct sock *sk; recv_pkt_info = @@ -900,6 +918,15 @@ static void vmci_transport_recv_pkt_work pkt = &recv_pkt_info->pkt; lock_sock(sk); + vsock_addr_init(&src, pkt->dg.src.context, pkt->src_port); + if (sk->sk_state != TCP_LISTEN && + (vsock_sk(sk)->transport != &vmci_transport || + src.svm_port != vsock_sk(sk)->remote_addr.svm_port || + (src.svm_cid != vsock_sk(sk)->remote_addr.svm_cid && + vmci_transport.get_local_cid() != VMADDR_CID_LOCAL))) { + vmci_transport_reply_reset(pkt); + goto out; + } /* The local context ID may be out of date. */ vsock_sk(sk)->local_addr.svm_cid = pkt->dg.dst.context; @@ -929,6 +956,7 @@ static void vmci_transport_recv_pkt_work break; } +out: release_sock(sk); kfree(recv_pkt_info); /* Release reference obtained in the stream callback when we fetched