Commit ddd3d408 authored by Stefan Hajnoczi's avatar Stefan Hajnoczi Committed by David S. Miller
Browse files

vhost: return bool from *_access_ok() functions 



Currently vhost *_access_ok() functions return int.  This is error-prone
because there are two popular conventions:

1. 0 means failure, 1 means success
2. -errno means failure, 0 means success

Although vhost mostly uses #1, it does not do so consistently.
umem_access_ok() uses #2.

This patch changes the return type from int to bool so that false means
failure and true means success.  This eliminates a potential source of
errors.

Suggested-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d14d2b78

drivers/vhost/vhost.c

+33 −33
Original line number Diff line number Diff line
@@ -641,14 +641,14 @@ void vhost_dev_cleanup(struct vhost_dev *dev) 
}

EXPORT_SYMBOL_GPL(vhost_dev_cleanup);



static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz)

static bool log_access_ok(void __user *log_base, u64 addr, unsigned long sz)

{

	u64 a = addr / VHOST_PAGE_SIZE / 8;



	/* Make sure 64 bit math will not overflow. */

	if (a > ULONG_MAX - (unsigned long)log_base ||

	    a + (unsigned long)log_base > ULONG_MAX)

		return 0;

		return false;



	return access_ok(VERIFY_WRITE, log_base + a,

			 (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8);
@@ -661,30 +661,30 @@ static bool vhost_overflow(u64 uaddr, u64 size) 
}



/* Caller should have vq mutex and device mutex. */

static int vq_memory_access_ok(void __user *log_base, struct vhost_umem *umem,

static bool vq_memory_access_ok(void __user *log_base, struct vhost_umem *umem,

				int log_all)

{

	struct vhost_umem_node *node;



	if (!umem)

		return 0;

		return false;



	list_for_each_entry(node, &umem->umem_list, link) {

		unsigned long a = node->userspace_addr;



		if (vhost_overflow(node->userspace_addr, node->size))

			return 0;

			return false;





		if (!access_ok(VERIFY_WRITE, (void __user *)a,

				    node->size))

			return 0;

			return false;

		else if (log_all && !log_access_ok(log_base,

						   node->start,

						   node->size))

			return 0;

			return false;

	}

	return 1;

	return true;

}



static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq,
@@ -701,13 +701,13 @@ static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq, 


/* Can we switch to this memory table? */

/* Caller should have device mutex but not vq mutex */

static int memory_access_ok(struct vhost_dev *d, struct vhost_umem *umem,

static bool memory_access_ok(struct vhost_dev *d, struct vhost_umem *umem,

			     int log_all)

{

	int i;



	for (i = 0; i < d->nvqs; ++i) {

		int ok;

		bool ok;

		bool log;



		mutex_lock(&d->vqs[i]->mutex);
@@ -717,12 +717,12 @@ static int memory_access_ok(struct vhost_dev *d, struct vhost_umem *umem, 
			ok = vq_memory_access_ok(d->vqs[i]->log_base,

						 umem, log);

		else

			ok = 1;

			ok = true;

		mutex_unlock(&d->vqs[i]->mutex);

		if (!ok)

			return 0;

			return false;

	}

	return 1;

	return true;

}



static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
@@ -959,21 +959,21 @@ static void vhost_iotlb_notify_vq(struct vhost_dev *d, 
	spin_unlock(&d->iotlb_lock);

}



static int umem_access_ok(u64 uaddr, u64 size, int access)

static bool umem_access_ok(u64 uaddr, u64 size, int access)

{

	unsigned long a = uaddr;



	/* Make sure 64 bit math will not overflow. */

	if (vhost_overflow(uaddr, size))

		return -EFAULT;

		return false;



	if ((access & VHOST_ACCESS_RO) &&

	    !access_ok(VERIFY_READ, (void __user *)a, size))

		return -EFAULT;

		return false;

	if ((access & VHOST_ACCESS_WO) &&

	    !access_ok(VERIFY_WRITE, (void __user *)a, size))

		return -EFAULT;

	return 0;

		return false;

	return true;

}



static int vhost_process_iotlb_msg(struct vhost_dev *dev,
@@ -988,7 +988,7 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev, 
			ret = -EFAULT;

			break;

		}

		if (umem_access_ok(msg->uaddr, msg->size, msg->perm)) {

		if (!umem_access_ok(msg->uaddr, msg->size, msg->perm)) {

			ret = -EFAULT;

			break;

		}
@@ -1135,7 +1135,7 @@ static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access) 
	return 0;

}



static int vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,

static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,

			 struct vring_desc __user *desc,

			 struct vring_avail __user *avail,

			 struct vring_used __user *used)
@@ -1161,7 +1161,7 @@ static void vhost_vq_meta_update(struct vhost_virtqueue *vq, 
		vq->meta_iotlb[type] = node;

}



static int iotlb_access_ok(struct vhost_virtqueue *vq,

static bool iotlb_access_ok(struct vhost_virtqueue *vq,

			    int access, u64 addr, u64 len, int type)

{

	const struct vhost_umem_node *node;
@@ -1220,7 +1220,7 @@ EXPORT_SYMBOL_GPL(vq_iotlb_prefetch); 


/* Can we log writes? */

/* Caller should have device mutex but not vq mutex */

int vhost_log_access_ok(struct vhost_dev *dev)

bool vhost_log_access_ok(struct vhost_dev *dev)

{

	return memory_access_ok(dev, dev->umem, 1);

}
@@ -1228,7 +1228,7 @@ EXPORT_SYMBOL_GPL(vhost_log_access_ok); 


/* Verify access for write logging. */

/* Caller should have vq mutex and device mutex */

static int vq_log_access_ok(struct vhost_virtqueue *vq,

static bool vq_log_access_ok(struct vhost_virtqueue *vq,

			     void __user *log_base)

{

	size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
@@ -1242,14 +1242,14 @@ static int vq_log_access_ok(struct vhost_virtqueue *vq, 


/* Can we start vq? */

/* Caller should have vq mutex and device mutex */

int vhost_vq_access_ok(struct vhost_virtqueue *vq)

bool vhost_vq_access_ok(struct vhost_virtqueue *vq)

{

	if (!vq_log_access_ok(vq, vq->log_base))

		return 0;

		return false;



	/* Access validation occurs at prefetch time with IOTLB */

	if (vq->iotlb)

		return 1;

		return true;



	return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used);

}

drivers/vhost/vhost.h

+2 −2
Original line number Diff line number Diff line
@@ -178,8 +178,8 @@ void vhost_dev_cleanup(struct vhost_dev *); 
void vhost_dev_stop(struct vhost_dev *);

long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);

long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp);

int vhost_vq_access_ok(struct vhost_virtqueue *vq);

int vhost_log_access_ok(struct vhost_dev *);

bool vhost_vq_access_ok(struct vhost_virtqueue *vq);

bool vhost_log_access_ok(struct vhost_dev *);



int vhost_get_vq_desc(struct vhost_virtqueue *,

		      struct iovec iov[], unsigned int iov_count,

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