[PATCH AUTOSEL 4.20 070/105] vhost: return EINVAL if iovecs size does not match the message size

Sasha Levin
2019-02-13T02:55:42Z

From: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>

[ 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>
---
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 cf82e7266397..7a07b0e86644 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -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;
--
2.19.1