This fixes two issues with recent access checking patch:
1. if (&d->vqs[i].private_data) -> if (d->vqs[i].private_data)
2. we can't forbid log base changes while ring is running,
because host needs to resize log in rare cases
(e.g. when memory is added with a baloon)
and in that case it needs to increase log size with realloc,
which might move the log address.
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
Rusty, this needs to be applied on top of the access_ok patch.
If you want me to rool it in with that one and esend, let me
know please.
Thanks!
drivers/vhost/vhost.c | 39 +++++++++++++++++++++++----------------
1 file changed, 23 insertions(+), 16 deletions(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 2b65d9b..c8c25db 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -230,7 +230,7 @@ static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
}
/* Caller should have vq mutex and device mutex. */
-static int vq_memory_access_ok(struct vhost_virtqueue *vq, struct vhost_memory *mem,
+static int vq_memory_access_ok(void __user *log_base, struct vhost_memory *mem,
int log_all)
{
int i;
@@ -242,7 +242,7 @@ static int vq_memory_access_ok(struct vhost_virtqueue *vq, struct vhost_memory *
else if (!access_ok(VERIFY_WRITE, (void __user *)a,
m->memory_size))
return 0;
- else if (log_all && !log_access_ok(vq->log_base,
+ else if (log_all && !log_access_ok(log_base,
m->guest_phys_addr,
m->memory_size))
return 0;
@@ -259,9 +259,10 @@ static int memory_access_ok(struct vhost_dev *d, struct vhost_memory *mem,
for (i = 0; i < d->nvqs; ++i) {
int ok;
mutex_lock(&d->vqs[i].mutex);
- /* If ring is not running, will check when it's enabled. */
- if (&d->vqs[i].private_data)
- ok = vq_memory_access_ok(&d->vqs[i], mem, log_all);
+ /* If ring is inactive, will check when it's enabled. */
+ if (d->vqs[i].private_data)
+ ok = vq_memory_access_ok(d->vqs[i].log_base, mem,
+ log_all);
else
ok = 1;
mutex_unlock(&d->vqs[i].mutex);
@@ -290,18 +291,25 @@ int vhost_log_access_ok(struct vhost_dev *dev)
return memory_access_ok(dev, dev->memory, 1);
}
-/* Can we start vq? */
+/* Verify access for write logging. */
/* Caller should have vq mutex and device mutex */
-int vhost_vq_access_ok(struct vhost_virtqueue *vq)
+static int vq_log_access_ok(struct vhost_virtqueue *vq, void __user *log_base)
{
- return vq_access_ok(vq->num, vq->desc, vq->avail, vq->used) &&
- vq_memory_access_ok(vq, vq->dev->memory,
+ return vq_memory_access_ok(log_base, vq->dev->memory,
vhost_has_feature(vq->dev, VHOST_F_LOG_ALL)) &&
- (!vq->log_used || log_access_ok(vq->log_base, vq->log_addr,
+ (!vq->log_used || log_access_ok(log_base, vq->log_addr,
sizeof *vq->used +
vq->num * sizeof *vq->used->ring));
}
+/* Can we start vq? */
+/* Caller should have vq mutex and device mutex */
+int vhost_vq_access_ok(struct vhost_virtqueue *vq)
+{
+ return vq_access_ok(vq->num, vq->desc, vq->avail, vq->used) &&
+ vq_log_access_ok(vq, vq->log_base);
+}
+
static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
{
struct vhost_memory mem, *newmem, *oldmem;
@@ -564,15 +572,14 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, unsigned long arg)
}
for (i = 0; i < d->nvqs; ++i) {
struct vhost_virtqueue *vq;
+ void __user *base = (void __user *)(unsigned long)p;
vq = d->vqs + i;
mutex_lock(&vq->mutex);
- /* Moving log base with an active backend?
- * You don't want to do that. */
- if (vq->private_data && (vq->log_used ||
- vhost_has_feature(d, VHOST_F_LOG_ALL)))
- r = -EBUSY;
+ /* If ring is inactive, will check when it's enabled. */
+ if (vq->private_data && !vq_log_access_ok(vq, base))
+ r = -EFAULT;
else
- vq->log_base = (void __user *)(unsigned long)p;
+ vq->log_base = base;
mutex_unlock(&vq->mutex);
}
break;
--
1.6.6.rc1.43.gf55cc
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