Stefano Garzarella
2022-Feb-22 09:47 UTC
[PATCH v2] vhost/vsock: don't check owner in vhost_vsock_stop() while releasing
vhost_vsock_stop() calls vhost_dev_check_owner() to check the device
ownership. It expects current->mm to be valid.
vhost_vsock_stop() is also called by vhost_vsock_dev_release() when
the user has not done close(), so when we are in do_exit(). In this
case current->mm is invalid and we're releasing the device, so we
should clean it anyway.
Let's check the owner only when vhost_vsock_stop() is called
by an ioctl.
When invoked from release we can not fail so we don't check return
code of vhost_vsock_stop(). We need to stop vsock even if it's not
the owner.
Fixes: 433fc58e6bf2 ("VSOCK: Introduce vhost_vsock.ko")
Cc: stable at vger.kernel.org
Reported-by: syzbot+1e3ea63db39f2b4440e0 at syzkaller.appspotmail.com
Reported-and-tested-by: syzbot+3140b17cb44a7b174008 at syzkaller.appspotmail.com
Signed-off-by: Stefano Garzarella <sgarzare at redhat.com>
---
v2:
- initialized `ret` in vhost_vsock_stop [Dan]
- added comment about vhost_vsock_stop() calling in the code and an explanation
in the commit message [MST]
v1: https://lore.kernel.org/virtualization/20220221114916.107045-1-sgarzare at
redhat.com
---
drivers/vhost/vsock.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index d6ca1c7ad513..37f0b4274113 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -629,16 +629,18 @@ static int vhost_vsock_start(struct vhost_vsock *vsock)
return ret;
}
-static int vhost_vsock_stop(struct vhost_vsock *vsock)
+static int vhost_vsock_stop(struct vhost_vsock *vsock, bool check_owner)
{
size_t i;
- int ret;
+ int ret = 0;
mutex_lock(&vsock->dev.mutex);
- ret = vhost_dev_check_owner(&vsock->dev);
- if (ret)
- goto err;
+ if (check_owner) {
+ ret = vhost_dev_check_owner(&vsock->dev);
+ if (ret)
+ goto err;
+ }
for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
struct vhost_virtqueue *vq = &vsock->vqs[i];
@@ -753,7 +755,12 @@ static int vhost_vsock_dev_release(struct inode *inode,
struct file *file)
* inefficient. Room for improvement here. */
vsock_for_each_connected_socket(vhost_vsock_reset_orphans);
- vhost_vsock_stop(vsock);
+ /* Don't check the owner, because we are in the release path, so we
+ * need to stop the vsock device in any case.
+ * vhost_vsock_stop() can not fail in this case, so we don't need to
+ * check the return code.
+ */
+ vhost_vsock_stop(vsock, false);
vhost_vsock_flush(vsock);
vhost_dev_stop(&vsock->dev);
@@ -868,7 +875,7 @@ static long vhost_vsock_dev_ioctl(struct file *f, unsigned
int ioctl,
if (start)
return vhost_vsock_start(vsock);
else
- return vhost_vsock_stop(vsock);
+ return vhost_vsock_stop(vsock, true);
case VHOST_GET_FEATURES:
features = VHOST_VSOCK_FEATURES;
if (copy_to_user(argp, &features, sizeof(features)))
--
2.35.1
Jason Wang
2022-Feb-23 02:09 UTC
[PATCH v2] vhost/vsock: don't check owner in vhost_vsock_stop() while releasing
On Tue, Feb 22, 2022 at 5:47 PM Stefano Garzarella <sgarzare at redhat.com> wrote:> > vhost_vsock_stop() calls vhost_dev_check_owner() to check the device > ownership. It expects current->mm to be valid. > > vhost_vsock_stop() is also called by vhost_vsock_dev_release() when > the user has not done close(), so when we are in do_exit(). In this > case current->mm is invalid and we're releasing the device, so we > should clean it anyway. > > Let's check the owner only when vhost_vsock_stop() is called > by an ioctl. > > When invoked from release we can not fail so we don't check return > code of vhost_vsock_stop(). We need to stop vsock even if it's not > the owner. > > Fixes: 433fc58e6bf2 ("VSOCK: Introduce vhost_vsock.ko") > Cc: stable at vger.kernel.org > Reported-by: syzbot+1e3ea63db39f2b4440e0 at syzkaller.appspotmail.com > Reported-and-tested-by: syzbot+3140b17cb44a7b174008 at syzkaller.appspotmail.com > Signed-off-by: Stefano Garzarella <sgarzare at redhat.com>Acked-by: Jason Wang <jasowang at redhat.com>> --- > v2: > - initialized `ret` in vhost_vsock_stop [Dan] > - added comment about vhost_vsock_stop() calling in the code and an explanation > in the commit message [MST] > > v1: https://lore.kernel.org/virtualization/20220221114916.107045-1-sgarzare at redhat.com > --- > drivers/vhost/vsock.c | 21 ++++++++++++++------- > 1 file changed, 14 insertions(+), 7 deletions(-) > > diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c > index d6ca1c7ad513..37f0b4274113 100644 > --- a/drivers/vhost/vsock.c > +++ b/drivers/vhost/vsock.c > @@ -629,16 +629,18 @@ static int vhost_vsock_start(struct vhost_vsock *vsock) > return ret; > } > > -static int vhost_vsock_stop(struct vhost_vsock *vsock) > +static int vhost_vsock_stop(struct vhost_vsock *vsock, bool check_owner) > { > size_t i; > - int ret; > + int ret = 0; > > mutex_lock(&vsock->dev.mutex); > > - ret = vhost_dev_check_owner(&vsock->dev); > - if (ret) > - goto err; > + if (check_owner) { > + ret = vhost_dev_check_owner(&vsock->dev); > + if (ret) > + goto err; > + } > > for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) { > struct vhost_virtqueue *vq = &vsock->vqs[i]; > @@ -753,7 +755,12 @@ static int vhost_vsock_dev_release(struct inode *inode, struct file *file) > * inefficient. Room for improvement here. */ > vsock_for_each_connected_socket(vhost_vsock_reset_orphans); > > - vhost_vsock_stop(vsock); > + /* Don't check the owner, because we are in the release path, so we > + * need to stop the vsock device in any case. > + * vhost_vsock_stop() can not fail in this case, so we don't need to > + * check the return code. > + */ > + vhost_vsock_stop(vsock, false); > vhost_vsock_flush(vsock); > vhost_dev_stop(&vsock->dev); > > @@ -868,7 +875,7 @@ static long vhost_vsock_dev_ioctl(struct file *f, unsigned int ioctl, > if (start) > return vhost_vsock_start(vsock); > else > - return vhost_vsock_stop(vsock); > + return vhost_vsock_stop(vsock, true); > case VHOST_GET_FEATURES: > features = VHOST_VSOCK_FEATURES; > if (copy_to_user(argp, &features, sizeof(features))) > -- > 2.35.1 >
Stefan Hajnoczi
2022-Feb-24 08:53 UTC
[PATCH v2] vhost/vsock: don't check owner in vhost_vsock_stop() while releasing
On Tue, Feb 22, 2022 at 10:47:42AM +0100, Stefano Garzarella wrote:> vhost_vsock_stop() calls vhost_dev_check_owner() to check the device > ownership. It expects current->mm to be valid. > > vhost_vsock_stop() is also called by vhost_vsock_dev_release() when > the user has not done close(), so when we are in do_exit(). In this > case current->mm is invalid and we're releasing the device, so we > should clean it anyway. > > Let's check the owner only when vhost_vsock_stop() is called > by an ioctl. > > When invoked from release we can not fail so we don't check return > code of vhost_vsock_stop(). We need to stop vsock even if it's not > the owner. > > Fixes: 433fc58e6bf2 ("VSOCK: Introduce vhost_vsock.ko") > Cc: stable at vger.kernel.org > Reported-by: syzbot+1e3ea63db39f2b4440e0 at syzkaller.appspotmail.com > Reported-and-tested-by: syzbot+3140b17cb44a7b174008 at syzkaller.appspotmail.com > Signed-off-by: Stefano Garzarella <sgarzare at redhat.com> > --- > v2: > - initialized `ret` in vhost_vsock_stop [Dan] > - added comment about vhost_vsock_stop() calling in the code and an explanation > in the commit message [MST] > > v1: https://lore.kernel.org/virtualization/20220221114916.107045-1-sgarzare at redhat.com > --- > drivers/vhost/vsock.c | 21 ++++++++++++++------- > 1 file changed, 14 insertions(+), 7 deletions(-)Reviewed-by: Stefan Hajnoczi <stefanha at redhat.com> -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 488 bytes Desc: not available URL: <http://lists.linuxfoundation.org/pipermail/virtualization/attachments/20220224/967b09a3/attachment.sig>