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![David S. Miller](/assets/img/avatar_default.png)
Several spots in the kernel perform a sequence like: skb_queue_tail(&sk->s_receive_queue, skb); sk->sk_data_ready(sk, skb->len); But at the moment we place the SKB onto the socket receive queue it can be consumed and freed up. So this skb->len access is potentially to freed up memory. Furthermore, the skb->len can be modified by the consumer so it is possible that the value isn't accurate. And finally, no actual implementation of this callback actually uses the length argument. And since nobody actually cared about it's value, lots of call sites pass arbitrary values in such as '0' and even '1'. So just remove the length argument from the callback, that way there is no confusion whatsoever and all of these use-after-free cases get fixed as a side effect. Based upon a patch by Eric Dumazet and his suggestion to audit this issue tree-wide. Signed-off-by: David S. Miller <davem@davemloft.net>
438 lines
11 KiB
C
438 lines
11 KiB
C
/*
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* VMware vSockets Driver
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*
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* Copyright (C) 2009-2013 VMware, Inc. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation version 2 and no later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*/
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#include <linux/types.h>
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#include <linux/socket.h>
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#include <linux/stddef.h>
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#include <net/sock.h>
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#include "vmci_transport_notify.h"
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#define PKT_FIELD(vsk, field_name) \
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(vmci_trans(vsk)->notify.pkt_q_state.field_name)
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static bool vmci_transport_notify_waiting_write(struct vsock_sock *vsk)
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{
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bool retval;
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u64 notify_limit;
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if (!PKT_FIELD(vsk, peer_waiting_write))
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return false;
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/* When the sender blocks, we take that as a sign that the sender is
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* faster than the receiver. To reduce the transmit rate of the sender,
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* we delay the sending of the read notification by decreasing the
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* write_notify_window. The notification is delayed until the number of
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* bytes used in the queue drops below the write_notify_window.
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*/
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if (!PKT_FIELD(vsk, peer_waiting_write_detected)) {
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PKT_FIELD(vsk, peer_waiting_write_detected) = true;
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if (PKT_FIELD(vsk, write_notify_window) < PAGE_SIZE) {
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PKT_FIELD(vsk, write_notify_window) =
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PKT_FIELD(vsk, write_notify_min_window);
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} else {
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PKT_FIELD(vsk, write_notify_window) -= PAGE_SIZE;
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if (PKT_FIELD(vsk, write_notify_window) <
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PKT_FIELD(vsk, write_notify_min_window))
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PKT_FIELD(vsk, write_notify_window) =
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PKT_FIELD(vsk, write_notify_min_window);
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}
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}
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notify_limit = vmci_trans(vsk)->consume_size -
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PKT_FIELD(vsk, write_notify_window);
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/* The notify_limit is used to delay notifications in the case where
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* flow control is enabled. Below the test is expressed in terms of
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* free space in the queue: if free_space > ConsumeSize -
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* write_notify_window then notify An alternate way of expressing this
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* is to rewrite the expression to use the data ready in the receive
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* queue: if write_notify_window > bufferReady then notify as
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* free_space == ConsumeSize - bufferReady.
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*/
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retval = vmci_qpair_consume_free_space(vmci_trans(vsk)->qpair) >
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notify_limit;
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if (retval) {
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/* Once we notify the peer, we reset the detected flag so the
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* next wait will again cause a decrease in the window size.
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*/
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PKT_FIELD(vsk, peer_waiting_write_detected) = false;
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}
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return retval;
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}
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static void
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vmci_transport_handle_read(struct sock *sk,
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struct vmci_transport_packet *pkt,
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bool bottom_half,
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struct sockaddr_vm *dst, struct sockaddr_vm *src)
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{
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sk->sk_write_space(sk);
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}
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static void
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vmci_transport_handle_wrote(struct sock *sk,
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struct vmci_transport_packet *pkt,
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bool bottom_half,
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struct sockaddr_vm *dst, struct sockaddr_vm *src)
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{
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sk->sk_data_ready(sk);
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}
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static void vsock_block_update_write_window(struct sock *sk)
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{
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struct vsock_sock *vsk = vsock_sk(sk);
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if (PKT_FIELD(vsk, write_notify_window) < vmci_trans(vsk)->consume_size)
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PKT_FIELD(vsk, write_notify_window) =
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min(PKT_FIELD(vsk, write_notify_window) + PAGE_SIZE,
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vmci_trans(vsk)->consume_size);
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}
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static int vmci_transport_send_read_notification(struct sock *sk)
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{
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struct vsock_sock *vsk;
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bool sent_read;
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unsigned int retries;
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int err;
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vsk = vsock_sk(sk);
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sent_read = false;
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retries = 0;
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err = 0;
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if (vmci_transport_notify_waiting_write(vsk)) {
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/* Notify the peer that we have read, retrying the send on
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* failure up to our maximum value. XXX For now we just log
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* the failure, but later we should schedule a work item to
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* handle the resend until it succeeds. That would require
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* keeping track of work items in the vsk and cleaning them up
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* upon socket close.
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*/
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while (!(vsk->peer_shutdown & RCV_SHUTDOWN) &&
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!sent_read &&
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retries < VMCI_TRANSPORT_MAX_DGRAM_RESENDS) {
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err = vmci_transport_send_read(sk);
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if (err >= 0)
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sent_read = true;
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retries++;
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}
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if (retries >= VMCI_TRANSPORT_MAX_DGRAM_RESENDS && !sent_read)
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pr_err("%p unable to send read notification to peer\n",
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sk);
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else
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PKT_FIELD(vsk, peer_waiting_write) = false;
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}
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return err;
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}
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static void vmci_transport_notify_pkt_socket_init(struct sock *sk)
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{
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struct vsock_sock *vsk = vsock_sk(sk);
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PKT_FIELD(vsk, write_notify_window) = PAGE_SIZE;
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PKT_FIELD(vsk, write_notify_min_window) = PAGE_SIZE;
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PKT_FIELD(vsk, peer_waiting_write) = false;
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PKT_FIELD(vsk, peer_waiting_write_detected) = false;
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}
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static void vmci_transport_notify_pkt_socket_destruct(struct vsock_sock *vsk)
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{
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PKT_FIELD(vsk, write_notify_window) = PAGE_SIZE;
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PKT_FIELD(vsk, write_notify_min_window) = PAGE_SIZE;
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PKT_FIELD(vsk, peer_waiting_write) = false;
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PKT_FIELD(vsk, peer_waiting_write_detected) = false;
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}
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static int
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vmci_transport_notify_pkt_poll_in(struct sock *sk,
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size_t target, bool *data_ready_now)
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{
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struct vsock_sock *vsk = vsock_sk(sk);
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if (vsock_stream_has_data(vsk)) {
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*data_ready_now = true;
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} else {
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/* We can't read right now because there is nothing in the
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* queue. Ask for notifications when there is something to
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* read.
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*/
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if (sk->sk_state == SS_CONNECTED)
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vsock_block_update_write_window(sk);
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*data_ready_now = false;
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}
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return 0;
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}
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static int
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vmci_transport_notify_pkt_poll_out(struct sock *sk,
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size_t target, bool *space_avail_now)
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{
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s64 produce_q_free_space;
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struct vsock_sock *vsk = vsock_sk(sk);
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produce_q_free_space = vsock_stream_has_space(vsk);
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if (produce_q_free_space > 0) {
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*space_avail_now = true;
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return 0;
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} else if (produce_q_free_space == 0) {
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/* This is a connected socket but we can't currently send data.
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* Nothing else to do.
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*/
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*space_avail_now = false;
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}
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return 0;
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}
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static int
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vmci_transport_notify_pkt_recv_init(
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struct sock *sk,
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size_t target,
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struct vmci_transport_recv_notify_data *data)
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{
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struct vsock_sock *vsk = vsock_sk(sk);
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data->consume_head = 0;
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data->produce_tail = 0;
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data->notify_on_block = false;
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if (PKT_FIELD(vsk, write_notify_min_window) < target + 1) {
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PKT_FIELD(vsk, write_notify_min_window) = target + 1;
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if (PKT_FIELD(vsk, write_notify_window) <
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PKT_FIELD(vsk, write_notify_min_window)) {
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/* If the current window is smaller than the new
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* minimal window size, we need to reevaluate whether
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* we need to notify the sender. If the number of ready
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* bytes are smaller than the new window, we need to
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* send a notification to the sender before we block.
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*/
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PKT_FIELD(vsk, write_notify_window) =
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PKT_FIELD(vsk, write_notify_min_window);
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data->notify_on_block = true;
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}
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}
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return 0;
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}
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static int
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vmci_transport_notify_pkt_recv_pre_block(
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struct sock *sk,
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size_t target,
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struct vmci_transport_recv_notify_data *data)
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{
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int err = 0;
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vsock_block_update_write_window(sk);
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if (data->notify_on_block) {
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err = vmci_transport_send_read_notification(sk);
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if (err < 0)
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return err;
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data->notify_on_block = false;
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}
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return err;
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}
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static int
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vmci_transport_notify_pkt_recv_post_dequeue(
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struct sock *sk,
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size_t target,
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ssize_t copied,
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bool data_read,
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struct vmci_transport_recv_notify_data *data)
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{
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struct vsock_sock *vsk;
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int err;
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bool was_full = false;
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u64 free_space;
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vsk = vsock_sk(sk);
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err = 0;
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if (data_read) {
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smp_mb();
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free_space =
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vmci_qpair_consume_free_space(vmci_trans(vsk)->qpair);
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was_full = free_space == copied;
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if (was_full)
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PKT_FIELD(vsk, peer_waiting_write) = true;
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err = vmci_transport_send_read_notification(sk);
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if (err < 0)
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return err;
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/* See the comment in
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* vmci_transport_notify_pkt_send_post_enqueue().
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*/
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sk->sk_data_ready(sk);
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}
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return err;
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}
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static int
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vmci_transport_notify_pkt_send_init(
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struct sock *sk,
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struct vmci_transport_send_notify_data *data)
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{
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data->consume_head = 0;
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data->produce_tail = 0;
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return 0;
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}
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static int
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vmci_transport_notify_pkt_send_post_enqueue(
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struct sock *sk,
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ssize_t written,
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struct vmci_transport_send_notify_data *data)
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{
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int err = 0;
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struct vsock_sock *vsk;
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bool sent_wrote = false;
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bool was_empty;
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int retries = 0;
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vsk = vsock_sk(sk);
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smp_mb();
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was_empty =
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vmci_qpair_produce_buf_ready(vmci_trans(vsk)->qpair) == written;
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if (was_empty) {
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while (!(vsk->peer_shutdown & RCV_SHUTDOWN) &&
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!sent_wrote &&
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retries < VMCI_TRANSPORT_MAX_DGRAM_RESENDS) {
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err = vmci_transport_send_wrote(sk);
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if (err >= 0)
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sent_wrote = true;
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retries++;
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}
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}
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if (retries >= VMCI_TRANSPORT_MAX_DGRAM_RESENDS && !sent_wrote) {
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pr_err("%p unable to send wrote notification to peer\n",
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sk);
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return err;
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}
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return err;
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}
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static void
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vmci_transport_notify_pkt_handle_pkt(
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struct sock *sk,
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struct vmci_transport_packet *pkt,
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bool bottom_half,
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struct sockaddr_vm *dst,
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struct sockaddr_vm *src, bool *pkt_processed)
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{
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bool processed = false;
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switch (pkt->type) {
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case VMCI_TRANSPORT_PACKET_TYPE_WROTE:
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vmci_transport_handle_wrote(sk, pkt, bottom_half, dst, src);
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processed = true;
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break;
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case VMCI_TRANSPORT_PACKET_TYPE_READ:
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vmci_transport_handle_read(sk, pkt, bottom_half, dst, src);
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processed = true;
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break;
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}
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if (pkt_processed)
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*pkt_processed = processed;
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}
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static void vmci_transport_notify_pkt_process_request(struct sock *sk)
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{
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struct vsock_sock *vsk = vsock_sk(sk);
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PKT_FIELD(vsk, write_notify_window) = vmci_trans(vsk)->consume_size;
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if (vmci_trans(vsk)->consume_size <
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PKT_FIELD(vsk, write_notify_min_window))
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PKT_FIELD(vsk, write_notify_min_window) =
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vmci_trans(vsk)->consume_size;
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}
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static void vmci_transport_notify_pkt_process_negotiate(struct sock *sk)
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{
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struct vsock_sock *vsk = vsock_sk(sk);
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PKT_FIELD(vsk, write_notify_window) = vmci_trans(vsk)->consume_size;
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if (vmci_trans(vsk)->consume_size <
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PKT_FIELD(vsk, write_notify_min_window))
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PKT_FIELD(vsk, write_notify_min_window) =
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vmci_trans(vsk)->consume_size;
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}
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static int
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vmci_transport_notify_pkt_recv_pre_dequeue(
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struct sock *sk,
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size_t target,
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struct vmci_transport_recv_notify_data *data)
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{
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return 0; /* NOP for QState. */
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}
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static int
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vmci_transport_notify_pkt_send_pre_block(
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struct sock *sk,
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struct vmci_transport_send_notify_data *data)
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{
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return 0; /* NOP for QState. */
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}
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static int
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vmci_transport_notify_pkt_send_pre_enqueue(
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struct sock *sk,
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struct vmci_transport_send_notify_data *data)
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{
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return 0; /* NOP for QState. */
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}
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/* Socket always on control packet based operations. */
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struct vmci_transport_notify_ops vmci_transport_notify_pkt_q_state_ops = {
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vmci_transport_notify_pkt_socket_init,
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vmci_transport_notify_pkt_socket_destruct,
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vmci_transport_notify_pkt_poll_in,
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vmci_transport_notify_pkt_poll_out,
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vmci_transport_notify_pkt_handle_pkt,
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vmci_transport_notify_pkt_recv_init,
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vmci_transport_notify_pkt_recv_pre_block,
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vmci_transport_notify_pkt_recv_pre_dequeue,
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vmci_transport_notify_pkt_recv_post_dequeue,
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vmci_transport_notify_pkt_send_init,
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vmci_transport_notify_pkt_send_pre_block,
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vmci_transport_notify_pkt_send_pre_enqueue,
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vmci_transport_notify_pkt_send_post_enqueue,
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vmci_transport_notify_pkt_process_request,
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vmci_transport_notify_pkt_process_negotiate,
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};
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