From: Dan Carpenter dan.carpenter@oracle.com
commit 7922460e33c81f41e0d2421417228b32e6fdbe94 upstream.
The copy_to/from_user() functions return the number of bytes which we weren't able to copy but the ioctl should return -EFAULT if they fail.
Fixes: a127c5bbb6a8 ("vhost-vdpa: fix backend feature ioctls") Signed-off-by: Dan Carpenter dan.carpenter@oracle.com Link: https://lore.kernel.org/r/20201023120853.GI282278@mwanda Signed-off-by: Michael S. Tsirkin mst@redhat.com Cc: stable@vger.kernel.org Acked-by: Jason Wang jasowang@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/vhost/vdpa.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
--- a/drivers/vhost/vdpa.c +++ b/drivers/vhost/vdpa.c @@ -428,12 +428,11 @@ static long vhost_vdpa_unlocked_ioctl(st void __user *argp = (void __user *)arg; u64 __user *featurep = argp; u64 features; - long r; + long r = 0;
if (cmd == VHOST_SET_BACKEND_FEATURES) { - r = copy_from_user(&features, featurep, sizeof(features)); - if (r) - return r; + if (copy_from_user(&features, featurep, sizeof(features))) + return -EFAULT; if (features & ~VHOST_VDPA_BACKEND_FEATURES) return -EOPNOTSUPP; vhost_set_backend_features(&v->vdev, features); @@ -476,7 +475,8 @@ static long vhost_vdpa_unlocked_ioctl(st break; case VHOST_GET_BACKEND_FEATURES: features = VHOST_VDPA_BACKEND_FEATURES; - r = copy_to_user(featurep, &features, sizeof(features)); + if (copy_to_user(featurep, &features, sizeof(features))) + r = -EFAULT; break; default: r = vhost_dev_ioctl(&v->vdev, cmd, argp);