/*
* virtio-blk Fuzzing Target
*
* Copyright Red Hat Inc., 2020
*
* Based on virtio-scsi-fuzz target.
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "tests/qtest/libqtest.h"
#include "tests/qtest/libqos/virtio-blk.h"
#include "tests/qtest/libqos/virtio.h"
#include "tests/qtest/libqos/virtio-pci.h"
#include "standard-headers/linux/virtio_ids.h"
#include "standard-headers/linux/virtio_pci.h"
#include "standard-headers/linux/virtio_blk.h"
#include "fuzz.h"
#include "fork_fuzz.h"
#include "qos_fuzz.h"
#define TEST_IMAGE_SIZE (64 * 1024 * 1024)
#define PCI_SLOT 0x02
#define PCI_FN 0x00
#define MAX_NUM_QUEUES 64
/* Based on tests/qtest/virtio-blk-test.c. */
typedef struct {
int num_queues;
QVirtQueue *vq[MAX_NUM_QUEUES + 2];
} QVirtioBlkQueues;
static QVirtioBlkQueues *qvirtio_blk_init(QVirtioDevice *dev, uint64_t mask)
{
QVirtioBlkQueues *vs;
uint64_t features;
vs = g_new0(QVirtioBlkQueues, 1);
features = qvirtio_get_features(dev);
if (!mask) {
mask = ~((1u << VIRTIO_RING_F_INDIRECT_DESC) |
(1u << VIRTIO_RING_F_EVENT_IDX) |
(1u << VIRTIO_BLK_F_SCSI));
}
mask |= ~QVIRTIO_F_BAD_FEATURE;
features &= mask;
qvirtio_set_features(dev, features);
vs->num_queues = 1;
vs->vq[0] = qvirtqueue_setup(dev, fuzz_qos_alloc, 0);
qvirtio_set_driver_ok(dev);
return vs;
}
static void virtio_blk_fuzz(QTestState *s, QVirtioBlkQueues* queues,
const unsigned char *Data, size_t Size)
{
/*
* Data is a sequence of random bytes. We split them up into "actions",
* followed by data:
* [vqa][dddddddd][vqa][dddd][vqa][dddddddddddd] ...
* The length of the data is specified by the preceding vqa.length
*/
typedef struct vq_action {
uint8_t queue;
uint8_t length;
uint8_t write;
uint8_t next;
uint8_t kick;
} vq_action;
/* Keep track of the free head for each queue we interact with */
bool vq_touched[MAX_NUM_QUEUES + 2] = {0};
uint32_t free_head[MAX_NUM_QUEUES + 2];
QGuestAllocator *t_alloc = fuzz_qos_alloc;
QVirtioBlk *blk = fuzz_qos_obj;
QVirtioDevice *dev = blk->vdev;
QVirtQueue *q;
vq_action vqa;
while (Size >= sizeof(vqa)) {
/* Copy the action, so we can normalize length, queue and flags */
memcpy(&vqa, Data, sizeof(vqa));
Data += sizeof(vqa);
Size -= sizeof(vqa);
vqa.queue = vqa.queue % queues->num_queues;
/* Cap length at the number of remaining bytes in data */
vqa.length = vqa.length >= Size ? Size : vqa.length;
vqa.write = vqa.write & 1;
vqa.next = vqa.next & 1;
vqa.kick = vqa.kick & 1;
q = queues->vq[vqa.queue];
/* Copy the data into ram, and place it on the virtqueue */
uint64_t req_addr = guest_alloc(t_alloc, vqa.length);
qtest_memwrite(s, req_addr, Data, vqa.length);
if (vq_touched[vqa.queue] == 0) {
vq_touched[vqa.queue] = 1;
free_head[vqa.queue] = qvirtqueue_add(s, q, req_addr, vqa.length,
vqa.write, vqa.next);
} else {
qvirtqueue_add(s, q, req_addr, vqa.length, vqa.write , vqa.next);
}
if (vqa.kick) {
qvirtqueue_kick(s, dev, q, free_head[vqa.queue]);
free_head[vqa.queue] = 0;
}
Data += vqa.length;
Size -= vqa.length;
}
/* In the end, kick each queue we interacted with */
for (int i = 0; i < MAX_NUM_QUEUES + 2; i++) {
if (vq_touched[i]) {
qvirtqueue_kick(s, dev, queues->vq[i], free_head[i]);
}
}
}
static void virtio_blk_fork_fuzz(QTestState *s,
const unsigned char *Data, size_t Size)
{
QVirtioBlk *blk = fuzz_qos_obj;
static QVirtioBlkQueues *queues;
if (!queues) {
queues = qvirtio_blk_init(blk->vdev, 0);
}
if (fork() == 0) {
virtio_blk_fuzz(s, queues, Data, Size);
flush_events(s);
_Exit(0);
} else {
flush_events(s);
wait(NULL);
}
}
static void virtio_blk_with_flag_fuzz(QTestState *s,
const unsigned char *Data, size_t Size)
{
QVirtioBlk *blk = fuzz_qos_obj;
static QVirtioBlkQueues *queues;
if (fork() == 0) {
if (Size >= sizeof(uint64_t)) {
queues = qvirtio_blk_init(blk->vdev, *(uint64_t *)Data);
virtio_blk_fuzz(s, queues,
Data + sizeof(uint64_t), Size - sizeof(uint64_t));
flush_events(s);
}
_Exit(0);
} else {
flush_events(s);
wait(NULL);
}
}
static void virtio_blk_pre_fuzz(QTestState *s)
{
qos_init_path(s);
counter_shm_init();
}
static void drive_destroy(void *path)
{
unlink(path);
g_free(path);
}
static char *drive_create(void)
{
int fd, ret;
char *t_path;
/* Create a temporary raw image */
fd = g_file_open_tmp("qtest.XXXXXX", &t_path, NULL);
g_assert_cmpint(fd, >=, 0);
ret = ftruncate(fd, TEST_IMAGE_SIZE);
g_assert_cmpint(ret, ==, 0);
close(fd);
g_test_queue_destroy(drive_destroy, t_path);
return t_path;
}
static void *virtio_blk_test_setup(GString *cmd_line, void *arg)
{
char *tmp_path = drive_create();
g_string_append_printf(cmd_line,
" -drive if=none,id=drive0,file=%s,"
"format=raw,auto-read-only=off ",
tmp_path);
return arg;
}
static void register_virtio_blk_fuzz_targets(void)
{
fuzz_add_qos_target(&(FuzzTarget){
.name = "virtio-blk-fuzz",
.description = "Fuzz the virtio-blk virtual queues, forking "
"for each fuzz run",
.pre_vm_init = &counter_shm_init,
.pre_fuzz = &virtio_blk_pre_fuzz,
.fuzz = virtio_blk_fork_fuzz,},
"virtio-blk",
&(QOSGraphTestOptions){.before = virtio_blk_test_setup}
);
fuzz_add_qos_target(&(FuzzTarget){
.name = "virtio-blk-flags-fuzz",
.description = "Fuzz the virtio-blk virtual queues, forking "
"for each fuzz run (also fuzzes the virtio flags)",
.pre_vm_init = &counter_shm_init,
.pre_fuzz = &virtio_blk_pre_fuzz,
.fuzz = virtio_blk_with_flag_fuzz,},
"virtio-blk",
&(QOSGraphTestOptions){.before = virtio_blk_test_setup}
);
}
fuzz_target_init(register_virtio_blk_fuzz_targets);
