1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3 * Copyright (c) 2022 Google, Inc.
4 * Written by Andrew Scull <ascull@google.com>
5 */
6
7 #include <dm.h>
8 #include <virtio.h>
9 #include <virtio_ring.h>
10 #include <test/fuzz.h>
11
fuzz_vring(const uint8_t * data,size_t size)12 static int fuzz_vring(const uint8_t *data, size_t size)
13 {
14 struct udevice *bus, *dev;
15 struct virtio_dev_priv *uc_priv;
16 struct virtqueue *vq;
17 struct virtio_sg sg[2];
18 struct virtio_sg *sgs[2];
19 unsigned int len;
20 u8 buffer[2][32];
21
22 /* hackily hardcode vring sizes */
23 size_t num = 4;
24 size_t desc_size = (sizeof(struct vring_desc) * num);
25 size_t avail_size = (3 + num) * sizeof(u16);
26 size_t used_size = (3 * sizeof(u16)) + (sizeof(struct vring_used_elem) * num);
27
28 if (size < (desc_size + avail_size + used_size))
29 return 0;
30
31 /* check probe success */
32 if (uclass_first_device_err(UCLASS_VIRTIO, &bus))
33 panic("Could not find virtio bus\n");
34
35 /* check the child virtio-rng device is bound */
36 if (device_find_first_child(bus, &dev) || !dev)
37 panic("Could not find virtio device\n");
38
39 /*
40 * fake the virtio device probe by filling in uc_priv->vdev
41 * which is used by virtio_find_vqs/virtio_del_vqs.
42 */
43 uc_priv = dev_get_uclass_priv(bus);
44 uc_priv->vdev = dev;
45
46 /* prepare the scatter-gather buffer */
47 sg[0].addr = buffer[0];
48 sg[0].length = sizeof(buffer[0]);
49 sg[1].addr = buffer[1];
50 sg[1].length = sizeof(buffer[1]);
51 sgs[0] = &sg[0];
52 sgs[1] = &sg[1];
53
54 if (virtio_find_vqs(dev, 1, &vq))
55 panic("Could not find vqs\n");
56 if (virtqueue_add(vq, sgs, 0, 1))
57 panic("Could not add to virtqueue\n");
58 /* Simulate device writing to vring */
59 memcpy(vq->vring.desc, data, desc_size);
60 memcpy(vq->vring.avail, data + desc_size, avail_size);
61 memcpy(vq->vring.used, data + desc_size + avail_size, used_size);
62 /* Make sure there is a response */
63 if (vq->vring.used->idx == 0)
64 vq->vring.used->idx = 1;
65 virtqueue_get_buf(vq, &len);
66 if (virtio_del_vqs(dev))
67 panic("Could not delete vqs\n");
68
69 return 0;
70 }
71 FUZZ_TEST(fuzz_vring, 0);
72