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/*
* virtio-net Fuzzing Target
*
* Copyright Red Hat Inc., 2019
*
* Authors:
* Alexander Bulekov <alxndr@bu.edu>
*
* 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 "standard-headers/linux/virtio_config.h"
#include "tests/qtest/libqos/libqtest.h"
#include "tests/qtest/libqos/virtio-net.h"
#include "fuzz.h"
#include "fork_fuzz.h"
#include "qos_fuzz.h"
#define QVIRTIO_NET_TIMEOUT_US (30 * 1000 * 1000)
#define QVIRTIO_RX_VQ 0
#define QVIRTIO_TX_VQ 1
#define QVIRTIO_CTRL_VQ 2
static int sockfds[2];
static bool sockfds_initialized;
static void virtio_net_fuzz_multi(QTestState *s,
const unsigned char *Data, size_t Size, bool check_used)
{
typedef struct vq_action {
uint8_t queue;
uint8_t length;
uint8_t write;
uint8_t next;
uint8_t rx;
} vq_action;
uint32_t free_head = 0;
QGuestAllocator *t_alloc = fuzz_qos_alloc;
QVirtioNet *net_if = fuzz_qos_obj;
QVirtioDevice *dev = net_if->vdev;
QVirtQueue *q;
vq_action vqa;
while (Size >= sizeof(vqa)) {
memcpy(&vqa, Data, sizeof(vqa));
Data += sizeof(vqa);
Size -= sizeof(vqa);
q = net_if->queues[vqa.queue % 3];
vqa.length = vqa.length >= Size ? Size : vqa.length;
/*
* Only attempt to write incoming packets, when using the socket
* backend. Otherwise, always place the input on a virtqueue.
*/
if (vqa.rx && sockfds_initialized) {
int ignored = write(sockfds[0], Data, vqa.length);
(void) ignored;
} else {
vqa.rx = 0;
uint64_t req_addr = guest_alloc(t_alloc, vqa.length);
/*
* If checking used ring, ensure that the fuzzer doesn't trigger
* trivial asserion failure on zero-zied buffer
*/
qtest_memwrite(s, req_addr, Data, vqa.length);
free_head = qvirtqueue_add(s, q, req_addr, vqa.length,
vqa.write, vqa.next);
qvirtqueue_add(s, q, req_addr, vqa.length, vqa.write , vqa.next);
qvirtqueue_kick(s, dev, q, free_head);
}
/* Run the main loop */
qtest_clock_step(s, 100);
flush_events(s);
/* Wait on used descriptors */
if (check_used && !vqa.rx) {
gint64 start_time = g_get_monotonic_time();
/*
* normally, we could just use qvirtio_wait_used_elem, but since we
* must manually run the main-loop for all the bhs to run, we use
* this hack with flush_events(), to run the main_loop
*/
while (!vqa.rx && q != net_if->queues[QVIRTIO_RX_VQ]) {
uint32_t got_desc_idx;
/* Input led to a virtio_error */
if (dev->bus->get_status(dev) & VIRTIO_CONFIG_S_NEEDS_RESET) {
break;
}
if (dev->bus->get_queue_isr_status(dev, q) &&
qvirtqueue_get_buf(s, q, &got_desc_idx, NULL)) {
g_assert_cmpint(got_desc_idx, ==, free_head);
break;
}
g_assert(g_get_monotonic_time() - start_time
<= QVIRTIO_NET_TIMEOUT_US);
/* Run the main loop */
qtest_clock_step(s, 100);
flush_events(s);
}
}
Data += vqa.length;
Size -= vqa.length;
}
}
static void virtio_net_fork_fuzz(QTestState *s,
const unsigned char *Data, size_t Size)
{
if (fork() == 0) {
virtio_net_fuzz_multi(s, Data, Size, false);
flush_events(s);
_Exit(0);
} else {
flush_events(s);
wait(NULL);
}
}
static void virtio_net_fork_fuzz_check_used(QTestState *s,
const unsigned char *Data, size_t Size)
{
if (fork() == 0) {
virtio_net_fuzz_multi(s, Data, Size, true);
flush_events(s);
_Exit(0);
} else {
flush_events(s);
wait(NULL);
}
}
static void virtio_net_pre_fuzz(QTestState *s)
{
qos_init_path(s);
counter_shm_init();
}
static void *virtio_net_test_setup_socket(GString *cmd_line, void *arg)
{
int ret = socketpair(PF_UNIX, SOCK_STREAM, 0, sockfds);
g_assert_cmpint(ret, !=, -1);
fcntl(sockfds[0], F_SETFL, O_NONBLOCK);
sockfds_initialized = true;
g_string_append_printf(cmd_line, " -netdev socket,fd=%d,id=hs0 ",
sockfds[1]);
return arg;
}
static void *virtio_net_test_setup_user(GString *cmd_line, void *arg)
{
g_string_append_printf(cmd_line, " -netdev user,id=hs0 ");
return arg;
}
static void register_virtio_net_fuzz_targets(void)
{
fuzz_add_qos_target(&(FuzzTarget){
.name = "virtio-net-socket",
.description = "Fuzz the virtio-net virtual queues. Fuzz incoming "
"traffic using the socket backend",
.pre_fuzz = &virtio_net_pre_fuzz,
.fuzz = virtio_net_fork_fuzz,},
"virtio-net",
&(QOSGraphTestOptions){.before = virtio_net_test_setup_socket}
);
fuzz_add_qos_target(&(FuzzTarget){
.name = "virtio-net-socket-check-used",
.description = "Fuzz the virtio-net virtual queues. Wait for the "
"descriptors to be used. Timeout may indicate improperly handled "
"input",
.pre_fuzz = &virtio_net_pre_fuzz,
.fuzz = virtio_net_fork_fuzz_check_used,},
"virtio-net",
&(QOSGraphTestOptions){.before = virtio_net_test_setup_socket}
);
fuzz_add_qos_target(&(FuzzTarget){
.name = "virtio-net-slirp",
.description = "Fuzz the virtio-net virtual queues with the slirp "
" backend. Warning: May result in network traffic emitted from the "
" process. Run in an isolated network environment.",
.pre_fuzz = &virtio_net_pre_fuzz,
.fuzz = virtio_net_fork_fuzz,},
"virtio-net",
&(QOSGraphTestOptions){.before = virtio_net_test_setup_user}
);
}
fuzz_target_init(register_virtio_net_fuzz_targets);
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