On 12/13/2018 10:55 PM, Michael S. Tsirkin wrote:
> On Thu, Dec 13, 2018 at 05:53:50PM +0300, Pavel Tikhomirov wrote:
>> 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 <ptikhomi...@virtuozzo.com>
>
> Thanks for the patch!
>
>> ---
>> drivers/vhost/vhost.c | 8 ++++++--
>> 1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
>> index 3a5f81a66d34..03014224ef13 100644
>> --- a/drivers/vhost/vhost.c
>> +++ b/drivers/vhost/vhost.c
>> @@ -1024,8 +1024,10 @@ 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:
>
> should this be EFAULT rather?
We already have "Invalid argument" returned when wrong type of vhost_msg
received, I though it would be fine to return same thing if we have
wrong size of vhost_msg.
When we return "Bad address" because of vhost_process_iotlb_msg fail, it
is because our vhost_dev has no ->iotlb so our problem is not connected
to the data passed from userspace but with the state of vhost_dev.
So I like EINVAL more in these two cases.
>
>> @@ -1044,8 +1046,10 @@ 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;
>
> This too?
>
>> --
>> 2.17.1
--
Best regards, Tikhomirov Pavel
Software Developer, Virtuozzo.
