linux/net/vmw_vsock/virtio_transport_common.c
Jia He 8692cefc43 virtio_vsock: Fix race condition in virtio_transport_recv_pkt
When client on the host tries to connect(SOCK_STREAM, O_NONBLOCK) to the
server on the guest, there will be a panic on a ThunderX2 (armv8a server):

[  463.718844] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
[  463.718848] Mem abort info:
[  463.718849]   ESR = 0x96000044
[  463.718852]   EC = 0x25: DABT (current EL), IL = 32 bits
[  463.718853]   SET = 0, FnV = 0
[  463.718854]   EA = 0, S1PTW = 0
[  463.718855] Data abort info:
[  463.718856]   ISV = 0, ISS = 0x00000044
[  463.718857]   CM = 0, WnR = 1
[  463.718859] user pgtable: 4k pages, 48-bit VAs, pgdp=0000008f6f6e9000
[  463.718861] [0000000000000000] pgd=0000000000000000
[  463.718866] Internal error: Oops: 96000044 [#1] SMP
[...]
[  463.718977] CPU: 213 PID: 5040 Comm: vhost-5032 Tainted: G           O      5.7.0-rc7+ #139
[  463.718980] Hardware name: GIGABYTE R281-T91-00/MT91-FS1-00, BIOS F06 09/25/2018
[  463.718982] pstate: 60400009 (nZCv daif +PAN -UAO)
[  463.718995] pc : virtio_transport_recv_pkt+0x4c8/0xd40 [vmw_vsock_virtio_transport_common]
[  463.718999] lr : virtio_transport_recv_pkt+0x1fc/0xd40 [vmw_vsock_virtio_transport_common]
[  463.719000] sp : ffff80002dbe3c40
[...]
[  463.719025] Call trace:
[  463.719030]  virtio_transport_recv_pkt+0x4c8/0xd40 [vmw_vsock_virtio_transport_common]
[  463.719034]  vhost_vsock_handle_tx_kick+0x360/0x408 [vhost_vsock]
[  463.719041]  vhost_worker+0x100/0x1a0 [vhost]
[  463.719048]  kthread+0x128/0x130
[  463.719052]  ret_from_fork+0x10/0x18

The race condition is as follows:
Task1                                Task2
=====                                =====
__sock_release                       virtio_transport_recv_pkt
  __vsock_release                      vsock_find_bound_socket (found sk)
    lock_sock_nested
    vsock_remove_sock
    sock_orphan
      sk_set_socket(sk, NULL)
    sk->sk_shutdown = SHUTDOWN_MASK
    ...
    release_sock
                                    lock_sock
                                       virtio_transport_recv_connecting
                                         sk->sk_socket->state (panic!)

The root cause is that vsock_find_bound_socket can't hold the lock_sock,
so there is a small race window between vsock_find_bound_socket() and
lock_sock(). If __vsock_release() is running in another task,
sk->sk_socket will be set to NULL inadvertently.

This fixes it by checking sk->sk_shutdown(suggested by Stefano) after
lock_sock since sk->sk_shutdown is set to SHUTDOWN_MASK under the
protection of lock_sock_nested.

Signed-off-by: Jia He <justin.he@arm.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-30 17:44:01 -07:00

1194 lines
28 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* common code for virtio vsock
*
* Copyright (C) 2013-2015 Red Hat, Inc.
* Author: Asias He <asias@redhat.com>
* Stefan Hajnoczi <stefanha@redhat.com>
*/
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/sched/signal.h>
#include <linux/ctype.h>
#include <linux/list.h>
#include <linux/virtio_vsock.h>
#include <uapi/linux/vsockmon.h>
#include <net/sock.h>
#include <net/af_vsock.h>
#define CREATE_TRACE_POINTS
#include <trace/events/vsock_virtio_transport_common.h>
/* How long to wait for graceful shutdown of a connection */
#define VSOCK_CLOSE_TIMEOUT (8 * HZ)
/* Threshold for detecting small packets to copy */
#define GOOD_COPY_LEN 128
static const struct virtio_transport *
virtio_transport_get_ops(struct vsock_sock *vsk)
{
const struct vsock_transport *t = vsock_core_get_transport(vsk);
if (WARN_ON(!t))
return NULL;
return container_of(t, struct virtio_transport, transport);
}
static struct virtio_vsock_pkt *
virtio_transport_alloc_pkt(struct virtio_vsock_pkt_info *info,
size_t len,
u32 src_cid,
u32 src_port,
u32 dst_cid,
u32 dst_port)
{
struct virtio_vsock_pkt *pkt;
int err;
pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
if (!pkt)
return NULL;
pkt->hdr.type = cpu_to_le16(info->type);
pkt->hdr.op = cpu_to_le16(info->op);
pkt->hdr.src_cid = cpu_to_le64(src_cid);
pkt->hdr.dst_cid = cpu_to_le64(dst_cid);
pkt->hdr.src_port = cpu_to_le32(src_port);
pkt->hdr.dst_port = cpu_to_le32(dst_port);
pkt->hdr.flags = cpu_to_le32(info->flags);
pkt->len = len;
pkt->hdr.len = cpu_to_le32(len);
pkt->reply = info->reply;
pkt->vsk = info->vsk;
if (info->msg && len > 0) {
pkt->buf = kmalloc(len, GFP_KERNEL);
if (!pkt->buf)
goto out_pkt;
pkt->buf_len = len;
err = memcpy_from_msg(pkt->buf, info->msg, len);
if (err)
goto out;
}
trace_virtio_transport_alloc_pkt(src_cid, src_port,
dst_cid, dst_port,
len,
info->type,
info->op,
info->flags);
return pkt;
out:
kfree(pkt->buf);
out_pkt:
kfree(pkt);
return NULL;
}
/* Packet capture */
static struct sk_buff *virtio_transport_build_skb(void *opaque)
{
struct virtio_vsock_pkt *pkt = opaque;
struct af_vsockmon_hdr *hdr;
struct sk_buff *skb;
size_t payload_len;
void *payload_buf;
/* A packet could be split to fit the RX buffer, so we can retrieve
* the payload length from the header and the buffer pointer taking
* care of the offset in the original packet.
*/
payload_len = le32_to_cpu(pkt->hdr.len);
payload_buf = pkt->buf + pkt->off;
skb = alloc_skb(sizeof(*hdr) + sizeof(pkt->hdr) + payload_len,
GFP_ATOMIC);
if (!skb)
return NULL;
hdr = skb_put(skb, sizeof(*hdr));
/* pkt->hdr is little-endian so no need to byteswap here */
hdr->src_cid = pkt->hdr.src_cid;
hdr->src_port = pkt->hdr.src_port;
hdr->dst_cid = pkt->hdr.dst_cid;
hdr->dst_port = pkt->hdr.dst_port;
hdr->transport = cpu_to_le16(AF_VSOCK_TRANSPORT_VIRTIO);
hdr->len = cpu_to_le16(sizeof(pkt->hdr));
memset(hdr->reserved, 0, sizeof(hdr->reserved));
switch (le16_to_cpu(pkt->hdr.op)) {
case VIRTIO_VSOCK_OP_REQUEST:
case VIRTIO_VSOCK_OP_RESPONSE:
hdr->op = cpu_to_le16(AF_VSOCK_OP_CONNECT);
break;
case VIRTIO_VSOCK_OP_RST:
case VIRTIO_VSOCK_OP_SHUTDOWN:
hdr->op = cpu_to_le16(AF_VSOCK_OP_DISCONNECT);
break;
case VIRTIO_VSOCK_OP_RW:
hdr->op = cpu_to_le16(AF_VSOCK_OP_PAYLOAD);
break;
case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
case VIRTIO_VSOCK_OP_CREDIT_REQUEST:
hdr->op = cpu_to_le16(AF_VSOCK_OP_CONTROL);
break;
default:
hdr->op = cpu_to_le16(AF_VSOCK_OP_UNKNOWN);
break;
}
skb_put_data(skb, &pkt->hdr, sizeof(pkt->hdr));
if (payload_len) {
skb_put_data(skb, payload_buf, payload_len);
}
return skb;
}
void virtio_transport_deliver_tap_pkt(struct virtio_vsock_pkt *pkt)
{
if (pkt->tap_delivered)
return;
vsock_deliver_tap(virtio_transport_build_skb, pkt);
pkt->tap_delivered = true;
}
EXPORT_SYMBOL_GPL(virtio_transport_deliver_tap_pkt);
/* This function can only be used on connecting/connected sockets,
* since a socket assigned to a transport is required.
*
* Do not use on listener sockets!
*/
static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
struct virtio_vsock_pkt_info *info)
{
u32 src_cid, src_port, dst_cid, dst_port;
const struct virtio_transport *t_ops;
struct virtio_vsock_sock *vvs;
struct virtio_vsock_pkt *pkt;
u32 pkt_len = info->pkt_len;
t_ops = virtio_transport_get_ops(vsk);
if (unlikely(!t_ops))
return -EFAULT;
src_cid = t_ops->transport.get_local_cid();
src_port = vsk->local_addr.svm_port;
if (!info->remote_cid) {
dst_cid = vsk->remote_addr.svm_cid;
dst_port = vsk->remote_addr.svm_port;
} else {
dst_cid = info->remote_cid;
dst_port = info->remote_port;
}
vvs = vsk->trans;
/* we can send less than pkt_len bytes */
if (pkt_len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE)
pkt_len = VIRTIO_VSOCK_MAX_PKT_BUF_SIZE;
/* virtio_transport_get_credit might return less than pkt_len credit */
pkt_len = virtio_transport_get_credit(vvs, pkt_len);
/* Do not send zero length OP_RW pkt */
if (pkt_len == 0 && info->op == VIRTIO_VSOCK_OP_RW)
return pkt_len;
pkt = virtio_transport_alloc_pkt(info, pkt_len,
src_cid, src_port,
dst_cid, dst_port);
if (!pkt) {
virtio_transport_put_credit(vvs, pkt_len);
return -ENOMEM;
}
virtio_transport_inc_tx_pkt(vvs, pkt);
return t_ops->send_pkt(pkt);
}
static bool virtio_transport_inc_rx_pkt(struct virtio_vsock_sock *vvs,
struct virtio_vsock_pkt *pkt)
{
if (vvs->rx_bytes + pkt->len > vvs->buf_alloc)
return false;
vvs->rx_bytes += pkt->len;
return true;
}
static void virtio_transport_dec_rx_pkt(struct virtio_vsock_sock *vvs,
struct virtio_vsock_pkt *pkt)
{
vvs->rx_bytes -= pkt->len;
vvs->fwd_cnt += pkt->len;
}
void virtio_transport_inc_tx_pkt(struct virtio_vsock_sock *vvs, struct virtio_vsock_pkt *pkt)
{
spin_lock_bh(&vvs->rx_lock);
vvs->last_fwd_cnt = vvs->fwd_cnt;
pkt->hdr.fwd_cnt = cpu_to_le32(vvs->fwd_cnt);
pkt->hdr.buf_alloc = cpu_to_le32(vvs->buf_alloc);
spin_unlock_bh(&vvs->rx_lock);
}
EXPORT_SYMBOL_GPL(virtio_transport_inc_tx_pkt);
u32 virtio_transport_get_credit(struct virtio_vsock_sock *vvs, u32 credit)
{
u32 ret;
spin_lock_bh(&vvs->tx_lock);
ret = vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt);
if (ret > credit)
ret = credit;
vvs->tx_cnt += ret;
spin_unlock_bh(&vvs->tx_lock);
return ret;
}
EXPORT_SYMBOL_GPL(virtio_transport_get_credit);
void virtio_transport_put_credit(struct virtio_vsock_sock *vvs, u32 credit)
{
spin_lock_bh(&vvs->tx_lock);
vvs->tx_cnt -= credit;
spin_unlock_bh(&vvs->tx_lock);
}
EXPORT_SYMBOL_GPL(virtio_transport_put_credit);
static int virtio_transport_send_credit_update(struct vsock_sock *vsk,
int type,
struct virtio_vsock_hdr *hdr)
{
struct virtio_vsock_pkt_info info = {
.op = VIRTIO_VSOCK_OP_CREDIT_UPDATE,
.type = type,
.vsk = vsk,
};
return virtio_transport_send_pkt_info(vsk, &info);
}
static ssize_t
virtio_transport_stream_do_peek(struct vsock_sock *vsk,
struct msghdr *msg,
size_t len)
{
struct virtio_vsock_sock *vvs = vsk->trans;
struct virtio_vsock_pkt *pkt;
size_t bytes, total = 0, off;
int err = -EFAULT;
spin_lock_bh(&vvs->rx_lock);
list_for_each_entry(pkt, &vvs->rx_queue, list) {
off = pkt->off;
if (total == len)
break;
while (total < len && off < pkt->len) {
bytes = len - total;
if (bytes > pkt->len - off)
bytes = pkt->len - off;
/* sk_lock is held by caller so no one else can dequeue.
* Unlock rx_lock since memcpy_to_msg() may sleep.
*/
spin_unlock_bh(&vvs->rx_lock);
err = memcpy_to_msg(msg, pkt->buf + off, bytes);
if (err)
goto out;
spin_lock_bh(&vvs->rx_lock);
total += bytes;
off += bytes;
}
}
spin_unlock_bh(&vvs->rx_lock);
return total;
out:
if (total)
err = total;
return err;
}
static ssize_t
virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
struct msghdr *msg,
size_t len)
{
struct virtio_vsock_sock *vvs = vsk->trans;
struct virtio_vsock_pkt *pkt;
size_t bytes, total = 0;
u32 free_space;
int err = -EFAULT;
spin_lock_bh(&vvs->rx_lock);
while (total < len && !list_empty(&vvs->rx_queue)) {
pkt = list_first_entry(&vvs->rx_queue,
struct virtio_vsock_pkt, list);
bytes = len - total;
if (bytes > pkt->len - pkt->off)
bytes = pkt->len - pkt->off;
/* sk_lock is held by caller so no one else can dequeue.
* Unlock rx_lock since memcpy_to_msg() may sleep.
*/
spin_unlock_bh(&vvs->rx_lock);
err = memcpy_to_msg(msg, pkt->buf + pkt->off, bytes);
if (err)
goto out;
spin_lock_bh(&vvs->rx_lock);
total += bytes;
pkt->off += bytes;
if (pkt->off == pkt->len) {
virtio_transport_dec_rx_pkt(vvs, pkt);
list_del(&pkt->list);
virtio_transport_free_pkt(pkt);
}
}
free_space = vvs->buf_alloc - (vvs->fwd_cnt - vvs->last_fwd_cnt);
spin_unlock_bh(&vvs->rx_lock);
/* To reduce the number of credit update messages,
* don't update credits as long as lots of space is available.
* Note: the limit chosen here is arbitrary. Setting the limit
* too high causes extra messages. Too low causes transmitter
* stalls. As stalls are in theory more expensive than extra
* messages, we set the limit to a high value. TODO: experiment
* with different values.
*/
if (free_space < VIRTIO_VSOCK_MAX_PKT_BUF_SIZE) {
virtio_transport_send_credit_update(vsk,
VIRTIO_VSOCK_TYPE_STREAM,
NULL);
}
return total;
out:
if (total)
err = total;
return err;
}
ssize_t
virtio_transport_stream_dequeue(struct vsock_sock *vsk,
struct msghdr *msg,
size_t len, int flags)
{
if (flags & MSG_PEEK)
return virtio_transport_stream_do_peek(vsk, msg, len);
else
return virtio_transport_stream_do_dequeue(vsk, msg, len);
}
EXPORT_SYMBOL_GPL(virtio_transport_stream_dequeue);
int
virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
struct msghdr *msg,
size_t len, int flags)
{
return -EOPNOTSUPP;
}
EXPORT_SYMBOL_GPL(virtio_transport_dgram_dequeue);
s64 virtio_transport_stream_has_data(struct vsock_sock *vsk)
{
struct virtio_vsock_sock *vvs = vsk->trans;
s64 bytes;
spin_lock_bh(&vvs->rx_lock);
bytes = vvs->rx_bytes;
spin_unlock_bh(&vvs->rx_lock);
return bytes;
}
EXPORT_SYMBOL_GPL(virtio_transport_stream_has_data);
static s64 virtio_transport_has_space(struct vsock_sock *vsk)
{
struct virtio_vsock_sock *vvs = vsk->trans;
s64 bytes;
bytes = vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt);
if (bytes < 0)
bytes = 0;
return bytes;
}
s64 virtio_transport_stream_has_space(struct vsock_sock *vsk)
{
struct virtio_vsock_sock *vvs = vsk->trans;
s64 bytes;
spin_lock_bh(&vvs->tx_lock);
bytes = virtio_transport_has_space(vsk);
spin_unlock_bh(&vvs->tx_lock);
return bytes;
}
EXPORT_SYMBOL_GPL(virtio_transport_stream_has_space);
int virtio_transport_do_socket_init(struct vsock_sock *vsk,
struct vsock_sock *psk)
{
struct virtio_vsock_sock *vvs;
vvs = kzalloc(sizeof(*vvs), GFP_KERNEL);
if (!vvs)
return -ENOMEM;
vsk->trans = vvs;
vvs->vsk = vsk;
if (psk && psk->trans) {
struct virtio_vsock_sock *ptrans = psk->trans;
vvs->peer_buf_alloc = ptrans->peer_buf_alloc;
}
if (vsk->buffer_size > VIRTIO_VSOCK_MAX_BUF_SIZE)
vsk->buffer_size = VIRTIO_VSOCK_MAX_BUF_SIZE;
vvs->buf_alloc = vsk->buffer_size;
spin_lock_init(&vvs->rx_lock);
spin_lock_init(&vvs->tx_lock);
INIT_LIST_HEAD(&vvs->rx_queue);
return 0;
}
EXPORT_SYMBOL_GPL(virtio_transport_do_socket_init);
/* sk_lock held by the caller */
void virtio_transport_notify_buffer_size(struct vsock_sock *vsk, u64 *val)
{
struct virtio_vsock_sock *vvs = vsk->trans;
if (*val > VIRTIO_VSOCK_MAX_BUF_SIZE)
*val = VIRTIO_VSOCK_MAX_BUF_SIZE;
vvs->buf_alloc = *val;
virtio_transport_send_credit_update(vsk, VIRTIO_VSOCK_TYPE_STREAM,
NULL);
}
EXPORT_SYMBOL_GPL(virtio_transport_notify_buffer_size);
int
virtio_transport_notify_poll_in(struct vsock_sock *vsk,
size_t target,
bool *data_ready_now)
{
if (vsock_stream_has_data(vsk))
*data_ready_now = true;
else
*data_ready_now = false;
return 0;
}
EXPORT_SYMBOL_GPL(virtio_transport_notify_poll_in);
int
virtio_transport_notify_poll_out(struct vsock_sock *vsk,
size_t target,
bool *space_avail_now)
{
s64 free_space;
free_space = vsock_stream_has_space(vsk);
if (free_space > 0)
*space_avail_now = true;
else if (free_space == 0)
*space_avail_now = false;
return 0;
}
EXPORT_SYMBOL_GPL(virtio_transport_notify_poll_out);
int virtio_transport_notify_recv_init(struct vsock_sock *vsk,
size_t target, struct vsock_transport_recv_notify_data *data)
{
return 0;
}
EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_init);
int virtio_transport_notify_recv_pre_block(struct vsock_sock *vsk,
size_t target, struct vsock_transport_recv_notify_data *data)
{
return 0;
}
EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_pre_block);
int virtio_transport_notify_recv_pre_dequeue(struct vsock_sock *vsk,
size_t target, struct vsock_transport_recv_notify_data *data)
{
return 0;
}
EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_pre_dequeue);
int virtio_transport_notify_recv_post_dequeue(struct vsock_sock *vsk,
size_t target, ssize_t copied, bool data_read,
struct vsock_transport_recv_notify_data *data)
{
return 0;
}
EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_post_dequeue);
int virtio_transport_notify_send_init(struct vsock_sock *vsk,
struct vsock_transport_send_notify_data *data)
{
return 0;
}
EXPORT_SYMBOL_GPL(virtio_transport_notify_send_init);
int virtio_transport_notify_send_pre_block(struct vsock_sock *vsk,
struct vsock_transport_send_notify_data *data)
{
return 0;
}
EXPORT_SYMBOL_GPL(virtio_transport_notify_send_pre_block);
int virtio_transport_notify_send_pre_enqueue(struct vsock_sock *vsk,
struct vsock_transport_send_notify_data *data)
{
return 0;
}
EXPORT_SYMBOL_GPL(virtio_transport_notify_send_pre_enqueue);
int virtio_transport_notify_send_post_enqueue(struct vsock_sock *vsk,
ssize_t written, struct vsock_transport_send_notify_data *data)
{
return 0;
}
EXPORT_SYMBOL_GPL(virtio_transport_notify_send_post_enqueue);
u64 virtio_transport_stream_rcvhiwat(struct vsock_sock *vsk)
{
return vsk->buffer_size;
}
EXPORT_SYMBOL_GPL(virtio_transport_stream_rcvhiwat);
bool virtio_transport_stream_is_active(struct vsock_sock *vsk)
{
return true;
}
EXPORT_SYMBOL_GPL(virtio_transport_stream_is_active);
bool virtio_transport_stream_allow(u32 cid, u32 port)
{
return true;
}
EXPORT_SYMBOL_GPL(virtio_transport_stream_allow);
int virtio_transport_dgram_bind(struct vsock_sock *vsk,
struct sockaddr_vm *addr)
{
return -EOPNOTSUPP;
}
EXPORT_SYMBOL_GPL(virtio_transport_dgram_bind);
bool virtio_transport_dgram_allow(u32 cid, u32 port)
{
return false;
}
EXPORT_SYMBOL_GPL(virtio_transport_dgram_allow);
int virtio_transport_connect(struct vsock_sock *vsk)
{
struct virtio_vsock_pkt_info info = {
.op = VIRTIO_VSOCK_OP_REQUEST,
.type = VIRTIO_VSOCK_TYPE_STREAM,
.vsk = vsk,
};
return virtio_transport_send_pkt_info(vsk, &info);
}
EXPORT_SYMBOL_GPL(virtio_transport_connect);
int virtio_transport_shutdown(struct vsock_sock *vsk, int mode)
{
struct virtio_vsock_pkt_info info = {
.op = VIRTIO_VSOCK_OP_SHUTDOWN,
.type = VIRTIO_VSOCK_TYPE_STREAM,
.flags = (mode & RCV_SHUTDOWN ?
VIRTIO_VSOCK_SHUTDOWN_RCV : 0) |
(mode & SEND_SHUTDOWN ?
VIRTIO_VSOCK_SHUTDOWN_SEND : 0),
.vsk = vsk,
};
return virtio_transport_send_pkt_info(vsk, &info);
}
EXPORT_SYMBOL_GPL(virtio_transport_shutdown);
int
virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
struct sockaddr_vm *remote_addr,
struct msghdr *msg,
size_t dgram_len)
{
return -EOPNOTSUPP;
}
EXPORT_SYMBOL_GPL(virtio_transport_dgram_enqueue);
ssize_t
virtio_transport_stream_enqueue(struct vsock_sock *vsk,
struct msghdr *msg,
size_t len)
{
struct virtio_vsock_pkt_info info = {
.op = VIRTIO_VSOCK_OP_RW,
.type = VIRTIO_VSOCK_TYPE_STREAM,
.msg = msg,
.pkt_len = len,
.vsk = vsk,
};
return virtio_transport_send_pkt_info(vsk, &info);
}
EXPORT_SYMBOL_GPL(virtio_transport_stream_enqueue);
void virtio_transport_destruct(struct vsock_sock *vsk)
{
struct virtio_vsock_sock *vvs = vsk->trans;
kfree(vvs);
}
EXPORT_SYMBOL_GPL(virtio_transport_destruct);
static int virtio_transport_reset(struct vsock_sock *vsk,
struct virtio_vsock_pkt *pkt)
{
struct virtio_vsock_pkt_info info = {
.op = VIRTIO_VSOCK_OP_RST,
.type = VIRTIO_VSOCK_TYPE_STREAM,
.reply = !!pkt,
.vsk = vsk,
};
/* Send RST only if the original pkt is not a RST pkt */
if (pkt && le16_to_cpu(pkt->hdr.op) == VIRTIO_VSOCK_OP_RST)
return 0;
return virtio_transport_send_pkt_info(vsk, &info);
}
/* Normally packets are associated with a socket. There may be no socket if an
* attempt was made to connect to a socket that does not exist.
*/
static int virtio_transport_reset_no_sock(const struct virtio_transport *t,
struct virtio_vsock_pkt *pkt)
{
struct virtio_vsock_pkt *reply;
struct virtio_vsock_pkt_info info = {
.op = VIRTIO_VSOCK_OP_RST,
.type = le16_to_cpu(pkt->hdr.type),
.reply = true,
};
/* Send RST only if the original pkt is not a RST pkt */
if (le16_to_cpu(pkt->hdr.op) == VIRTIO_VSOCK_OP_RST)
return 0;
reply = virtio_transport_alloc_pkt(&info, 0,
le64_to_cpu(pkt->hdr.dst_cid),
le32_to_cpu(pkt->hdr.dst_port),
le64_to_cpu(pkt->hdr.src_cid),
le32_to_cpu(pkt->hdr.src_port));
if (!reply)
return -ENOMEM;
if (!t) {
virtio_transport_free_pkt(reply);
return -ENOTCONN;
}
return t->send_pkt(reply);
}
static void virtio_transport_wait_close(struct sock *sk, long timeout)
{
if (timeout) {
DEFINE_WAIT_FUNC(wait, woken_wake_function);
add_wait_queue(sk_sleep(sk), &wait);
do {
if (sk_wait_event(sk, &timeout,
sock_flag(sk, SOCK_DONE), &wait))
break;
} while (!signal_pending(current) && timeout);
remove_wait_queue(sk_sleep(sk), &wait);
}
}
static void virtio_transport_do_close(struct vsock_sock *vsk,
bool cancel_timeout)
{
struct sock *sk = sk_vsock(vsk);
sock_set_flag(sk, SOCK_DONE);
vsk->peer_shutdown = SHUTDOWN_MASK;
if (vsock_stream_has_data(vsk) <= 0)
sk->sk_state = TCP_CLOSING;
sk->sk_state_change(sk);
if (vsk->close_work_scheduled &&
(!cancel_timeout || cancel_delayed_work(&vsk->close_work))) {
vsk->close_work_scheduled = false;
vsock_remove_sock(vsk);
/* Release refcnt obtained when we scheduled the timeout */
sock_put(sk);
}
}
static void virtio_transport_close_timeout(struct work_struct *work)
{
struct vsock_sock *vsk =
container_of(work, struct vsock_sock, close_work.work);
struct sock *sk = sk_vsock(vsk);
sock_hold(sk);
lock_sock(sk);
if (!sock_flag(sk, SOCK_DONE)) {
(void)virtio_transport_reset(vsk, NULL);
virtio_transport_do_close(vsk, false);
}
vsk->close_work_scheduled = false;
release_sock(sk);
sock_put(sk);
}
/* User context, vsk->sk is locked */
static bool virtio_transport_close(struct vsock_sock *vsk)
{
struct sock *sk = &vsk->sk;
if (!(sk->sk_state == TCP_ESTABLISHED ||
sk->sk_state == TCP_CLOSING))
return true;
/* Already received SHUTDOWN from peer, reply with RST */
if ((vsk->peer_shutdown & SHUTDOWN_MASK) == SHUTDOWN_MASK) {
(void)virtio_transport_reset(vsk, NULL);
return true;
}
if ((sk->sk_shutdown & SHUTDOWN_MASK) != SHUTDOWN_MASK)
(void)virtio_transport_shutdown(vsk, SHUTDOWN_MASK);
if (sock_flag(sk, SOCK_LINGER) && !(current->flags & PF_EXITING))
virtio_transport_wait_close(sk, sk->sk_lingertime);
if (sock_flag(sk, SOCK_DONE)) {
return true;
}
sock_hold(sk);
INIT_DELAYED_WORK(&vsk->close_work,
virtio_transport_close_timeout);
vsk->close_work_scheduled = true;
schedule_delayed_work(&vsk->close_work, VSOCK_CLOSE_TIMEOUT);
return false;
}
void virtio_transport_release(struct vsock_sock *vsk)
{
struct virtio_vsock_sock *vvs = vsk->trans;
struct virtio_vsock_pkt *pkt, *tmp;
struct sock *sk = &vsk->sk;
bool remove_sock = true;
if (sk->sk_type == SOCK_STREAM)
remove_sock = virtio_transport_close(vsk);
list_for_each_entry_safe(pkt, tmp, &vvs->rx_queue, list) {
list_del(&pkt->list);
virtio_transport_free_pkt(pkt);
}
if (remove_sock)
vsock_remove_sock(vsk);
}
EXPORT_SYMBOL_GPL(virtio_transport_release);
static int
virtio_transport_recv_connecting(struct sock *sk,
struct virtio_vsock_pkt *pkt)
{
struct vsock_sock *vsk = vsock_sk(sk);
int err;
int skerr;
switch (le16_to_cpu(pkt->hdr.op)) {
case VIRTIO_VSOCK_OP_RESPONSE:
sk->sk_state = TCP_ESTABLISHED;
sk->sk_socket->state = SS_CONNECTED;
vsock_insert_connected(vsk);
sk->sk_state_change(sk);
break;
case VIRTIO_VSOCK_OP_INVALID:
break;
case VIRTIO_VSOCK_OP_RST:
skerr = ECONNRESET;
err = 0;
goto destroy;
default:
skerr = EPROTO;
err = -EINVAL;
goto destroy;
}
return 0;
destroy:
virtio_transport_reset(vsk, pkt);
sk->sk_state = TCP_CLOSE;
sk->sk_err = skerr;
sk->sk_error_report(sk);
return err;
}
static void
virtio_transport_recv_enqueue(struct vsock_sock *vsk,
struct virtio_vsock_pkt *pkt)
{
struct virtio_vsock_sock *vvs = vsk->trans;
bool can_enqueue, free_pkt = false;
pkt->len = le32_to_cpu(pkt->hdr.len);
pkt->off = 0;
spin_lock_bh(&vvs->rx_lock);
can_enqueue = virtio_transport_inc_rx_pkt(vvs, pkt);
if (!can_enqueue) {
free_pkt = true;
goto out;
}
/* Try to copy small packets into the buffer of last packet queued,
* to avoid wasting memory queueing the entire buffer with a small
* payload.
*/
if (pkt->len <= GOOD_COPY_LEN && !list_empty(&vvs->rx_queue)) {
struct virtio_vsock_pkt *last_pkt;
last_pkt = list_last_entry(&vvs->rx_queue,
struct virtio_vsock_pkt, list);
/* If there is space in the last packet queued, we copy the
* new packet in its buffer.
*/
if (pkt->len <= last_pkt->buf_len - last_pkt->len) {
memcpy(last_pkt->buf + last_pkt->len, pkt->buf,
pkt->len);
last_pkt->len += pkt->len;
free_pkt = true;
goto out;
}
}
list_add_tail(&pkt->list, &vvs->rx_queue);
out:
spin_unlock_bh(&vvs->rx_lock);
if (free_pkt)
virtio_transport_free_pkt(pkt);
}
static int
virtio_transport_recv_connected(struct sock *sk,
struct virtio_vsock_pkt *pkt)
{
struct vsock_sock *vsk = vsock_sk(sk);
int err = 0;
switch (le16_to_cpu(pkt->hdr.op)) {
case VIRTIO_VSOCK_OP_RW:
virtio_transport_recv_enqueue(vsk, pkt);
sk->sk_data_ready(sk);
return err;
case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
sk->sk_write_space(sk);
break;
case VIRTIO_VSOCK_OP_SHUTDOWN:
if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SHUTDOWN_RCV)
vsk->peer_shutdown |= RCV_SHUTDOWN;
if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SHUTDOWN_SEND)
vsk->peer_shutdown |= SEND_SHUTDOWN;
if (vsk->peer_shutdown == SHUTDOWN_MASK &&
vsock_stream_has_data(vsk) <= 0 &&
!sock_flag(sk, SOCK_DONE)) {
(void)virtio_transport_reset(vsk, NULL);
virtio_transport_do_close(vsk, true);
}
if (le32_to_cpu(pkt->hdr.flags))
sk->sk_state_change(sk);
break;
case VIRTIO_VSOCK_OP_RST:
virtio_transport_do_close(vsk, true);
break;
default:
err = -EINVAL;
break;
}
virtio_transport_free_pkt(pkt);
return err;
}
static void
virtio_transport_recv_disconnecting(struct sock *sk,
struct virtio_vsock_pkt *pkt)
{
struct vsock_sock *vsk = vsock_sk(sk);
if (le16_to_cpu(pkt->hdr.op) == VIRTIO_VSOCK_OP_RST)
virtio_transport_do_close(vsk, true);
}
static int
virtio_transport_send_response(struct vsock_sock *vsk,
struct virtio_vsock_pkt *pkt)
{
struct virtio_vsock_pkt_info info = {
.op = VIRTIO_VSOCK_OP_RESPONSE,
.type = VIRTIO_VSOCK_TYPE_STREAM,
.remote_cid = le64_to_cpu(pkt->hdr.src_cid),
.remote_port = le32_to_cpu(pkt->hdr.src_port),
.reply = true,
.vsk = vsk,
};
return virtio_transport_send_pkt_info(vsk, &info);
}
static bool virtio_transport_space_update(struct sock *sk,
struct virtio_vsock_pkt *pkt)
{
struct vsock_sock *vsk = vsock_sk(sk);
struct virtio_vsock_sock *vvs = vsk->trans;
bool space_available;
/* Listener sockets are not associated with any transport, so we are
* not able to take the state to see if there is space available in the
* remote peer, but since they are only used to receive requests, we
* can assume that there is always space available in the other peer.
*/
if (!vvs)
return true;
/* buf_alloc and fwd_cnt is always included in the hdr */
spin_lock_bh(&vvs->tx_lock);
vvs->peer_buf_alloc = le32_to_cpu(pkt->hdr.buf_alloc);
vvs->peer_fwd_cnt = le32_to_cpu(pkt->hdr.fwd_cnt);
space_available = virtio_transport_has_space(vsk);
spin_unlock_bh(&vvs->tx_lock);
return space_available;
}
/* Handle server socket */
static int
virtio_transport_recv_listen(struct sock *sk, struct virtio_vsock_pkt *pkt,
struct virtio_transport *t)
{
struct vsock_sock *vsk = vsock_sk(sk);
struct vsock_sock *vchild;
struct sock *child;
int ret;
if (le16_to_cpu(pkt->hdr.op) != VIRTIO_VSOCK_OP_REQUEST) {
virtio_transport_reset_no_sock(t, pkt);
return -EINVAL;
}
if (sk_acceptq_is_full(sk)) {
virtio_transport_reset_no_sock(t, pkt);
return -ENOMEM;
}
child = vsock_create_connected(sk);
if (!child) {
virtio_transport_reset_no_sock(t, pkt);
return -ENOMEM;
}
sk_acceptq_added(sk);
lock_sock_nested(child, SINGLE_DEPTH_NESTING);
child->sk_state = TCP_ESTABLISHED;
vchild = vsock_sk(child);
vsock_addr_init(&vchild->local_addr, le64_to_cpu(pkt->hdr.dst_cid),
le32_to_cpu(pkt->hdr.dst_port));
vsock_addr_init(&vchild->remote_addr, le64_to_cpu(pkt->hdr.src_cid),
le32_to_cpu(pkt->hdr.src_port));
ret = vsock_assign_transport(vchild, vsk);
/* Transport assigned (looking at remote_addr) must be the same
* where we received the request.
*/
if (ret || vchild->transport != &t->transport) {
release_sock(child);
virtio_transport_reset_no_sock(t, pkt);
sock_put(child);
return ret;
}
if (virtio_transport_space_update(child, pkt))
child->sk_write_space(child);
vsock_insert_connected(vchild);
vsock_enqueue_accept(sk, child);
virtio_transport_send_response(vchild, pkt);
release_sock(child);
sk->sk_data_ready(sk);
return 0;
}
/* We are under the virtio-vsock's vsock->rx_lock or vhost-vsock's vq->mutex
* lock.
*/
void virtio_transport_recv_pkt(struct virtio_transport *t,
struct virtio_vsock_pkt *pkt)
{
struct sockaddr_vm src, dst;
struct vsock_sock *vsk;
struct sock *sk;
bool space_available;
vsock_addr_init(&src, le64_to_cpu(pkt->hdr.src_cid),
le32_to_cpu(pkt->hdr.src_port));
vsock_addr_init(&dst, le64_to_cpu(pkt->hdr.dst_cid),
le32_to_cpu(pkt->hdr.dst_port));
trace_virtio_transport_recv_pkt(src.svm_cid, src.svm_port,
dst.svm_cid, dst.svm_port,
le32_to_cpu(pkt->hdr.len),
le16_to_cpu(pkt->hdr.type),
le16_to_cpu(pkt->hdr.op),
le32_to_cpu(pkt->hdr.flags),
le32_to_cpu(pkt->hdr.buf_alloc),
le32_to_cpu(pkt->hdr.fwd_cnt));
if (le16_to_cpu(pkt->hdr.type) != VIRTIO_VSOCK_TYPE_STREAM) {
(void)virtio_transport_reset_no_sock(t, pkt);
goto free_pkt;
}
/* The socket must be in connected or bound table
* otherwise send reset back
*/
sk = vsock_find_connected_socket(&src, &dst);
if (!sk) {
sk = vsock_find_bound_socket(&dst);
if (!sk) {
(void)virtio_transport_reset_no_sock(t, pkt);
goto free_pkt;
}
}
vsk = vsock_sk(sk);
space_available = virtio_transport_space_update(sk, pkt);
lock_sock(sk);
/* Check if sk has been released before lock_sock */
if (sk->sk_shutdown == SHUTDOWN_MASK) {
(void)virtio_transport_reset_no_sock(t, pkt);
release_sock(sk);
sock_put(sk);
goto free_pkt;
}
/* Update CID in case it has changed after a transport reset event */
vsk->local_addr.svm_cid = dst.svm_cid;
if (space_available)
sk->sk_write_space(sk);
switch (sk->sk_state) {
case TCP_LISTEN:
virtio_transport_recv_listen(sk, pkt, t);
virtio_transport_free_pkt(pkt);
break;
case TCP_SYN_SENT:
virtio_transport_recv_connecting(sk, pkt);
virtio_transport_free_pkt(pkt);
break;
case TCP_ESTABLISHED:
virtio_transport_recv_connected(sk, pkt);
break;
case TCP_CLOSING:
virtio_transport_recv_disconnecting(sk, pkt);
virtio_transport_free_pkt(pkt);
break;
default:
(void)virtio_transport_reset_no_sock(t, pkt);
virtio_transport_free_pkt(pkt);
break;
}
release_sock(sk);
/* Release refcnt obtained when we fetched this socket out of the
* bound or connected list.
*/
sock_put(sk);
return;
free_pkt:
virtio_transport_free_pkt(pkt);
}
EXPORT_SYMBOL_GPL(virtio_transport_recv_pkt);
void virtio_transport_free_pkt(struct virtio_vsock_pkt *pkt)
{
kfree(pkt->buf);
kfree(pkt);
}
EXPORT_SYMBOL_GPL(virtio_transport_free_pkt);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Asias He");
MODULE_DESCRIPTION("common code for virtio vsock");