Commit 5604fdcf authored Dec 13, 2018 by Pavel Tikhomirov Committed by Greg Kroah-Hartman Feb 27, 2019

vhost: return EINVAL if iovecs size does not match the message size



[ Upstream commit 74ad7419489ddade8044e3c9ab064ad656520306 ]

We've failed to copy and process vhost_iotlb_msg so let userspace at
least know about it. For instance before these patch the code below runs
without any error:

int main()
{
  struct vhost_msg msg;
  struct iovec iov;
  int fd;

  fd = open("/dev/vhost-net", O_RDWR);
  if (fd == -1) {
    perror("open");
    return 1;
  }

  iov.iov_base = &msg;
  iov.iov_len = sizeof(msg)-4;

  if (writev(fd, &iov,1) == -1) {
    perror("writev");
    return 1;
  }

  return 0;
}

Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 096a3170

drivers/vhost/vhost.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -1035,8 +1035,10 @@ ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
		int type, ret;

		ret = copy_from_iter(&type, sizeof(type), from);
		if (ret != sizeof(type))
		if (ret != sizeof(type)) {
		ret = -EINVAL;
		goto done;
		}

		switch (type) {
		case VHOST_IOTLB_MSG:
		@@ -1055,8 +1057,10 @@ ssize_t vhost_chr_write_iter(struct vhost_dev *dev,

		iov_iter_advance(from, offset);
		ret = copy_from_iter(&msg, sizeof(msg), from);
		if (ret != sizeof(msg))
		if (ret != sizeof(msg)) {
		ret = -EINVAL;
		goto done;
		}
		if (vhost_process_iotlb_msg(dev, &msg)) {
		ret = -EFAULT;
		goto done;