tests/qtest/fuzz/virtio_net_fuzz.c

   1 /*
   2  * virtio-net Fuzzing Target
   3  *
   4  * Copyright Red Hat Inc., 2019
   5  *
   6  * Authors:
   7  *  Alexander Bulekov   <alxndr@bu.edu>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  */
  12
  13 #include "qemu/osdep.h"
  14
  15 #include "standard-headers/linux/virtio_config.h"
  16 #include "tests/qtest/libqtest.h"
  17 #include "tests/qtest/libqos/virtio-net.h"
  18 #include "fuzz.h"
  19 #include "fork_fuzz.h"
  20 #include "qos_fuzz.h"
  21
  22
  23 #define QVIRTIO_NET_TIMEOUT_US (30 * 1000 * 1000)
  24 #define QVIRTIO_RX_VQ 0
  25 #define QVIRTIO_TX_VQ 1
  26 #define QVIRTIO_CTRL_VQ 2
  27
  28 static int sockfds[2];
  29 static bool sockfds_initialized;
  30
  31 static void virtio_net_fuzz_multi(QTestState *s,
  32         const unsigned char *Data, size_t Size, bool check_used)
  33 {
  34     typedef struct vq_action {
  35         uint8_t queue;
  36         uint8_t length;
  37         uint8_t write;
  38         uint8_t next;
  39         uint8_t rx;
  40     } vq_action;
  41
  42     uint32_t free_head = 0;
  43
  44     QGuestAllocator *t_alloc = fuzz_qos_alloc;
  45
  46     QVirtioNet *net_if = fuzz_qos_obj;
  47     QVirtioDevice *dev = net_if->vdev;
  48     QVirtQueue *q;
  49     vq_action vqa;
  50     while (Size >= sizeof(vqa)) {
  51         memcpy(&vqa, Data, sizeof(vqa));
  52         Data += sizeof(vqa);
  53         Size -= sizeof(vqa);
  54
  55         q = net_if->queues[vqa.queue % 3];
  56
  57         vqa.length = vqa.length >= Size ? Size :  vqa.length;
  58
  59         /*
  60          * Only attempt to write incoming packets, when using the socket
  61          * backend. Otherwise, always place the input on a virtqueue.
  62          */
  63         if (vqa.rx && sockfds_initialized) {
  64             write(sockfds[0], Data, vqa.length);
  65         } else {
  66             vqa.rx = 0;
  67             uint64_t req_addr = guest_alloc(t_alloc, vqa.length);
  68             /*
  69              * If checking used ring, ensure that the fuzzer doesn't trigger
  70              * trivial asserion failure on zero-zied buffer
  71              */
  72             qtest_memwrite(s, req_addr, Data, vqa.length);
  73
  74
  75             free_head = qvirtqueue_add(s, q, req_addr, vqa.length,
  76                     vqa.write, vqa.next);
  77             qvirtqueue_add(s, q, req_addr, vqa.length, vqa.write , vqa.next);
  78             qvirtqueue_kick(s, dev, q, free_head);
  79         }
  80
  81         /* Run the main loop */
  82         qtest_clock_step(s, 100);
  83         flush_events(s);
  84
  85         /* Wait on used descriptors */
  86         if (check_used && !vqa.rx) {
  87             gint64 start_time = g_get_monotonic_time();
  88             /*
  89              * normally, we could just use qvirtio_wait_used_elem, but since we
  90              * must manually run the main-loop for all the bhs to run, we use
  91              * this hack with flush_events(), to run the main_loop
  92              */
  93             while (!vqa.rx && q != net_if->queues[QVIRTIO_RX_VQ]) {
  94                 uint32_t got_desc_idx;
  95                 /* Input led to a virtio_error */
  96                 if (dev->bus->get_status(dev) & VIRTIO_CONFIG_S_NEEDS_RESET) {
  97                     break;
  98                 }
  99                 if (dev->bus->get_queue_isr_status(dev, q) &&
 100                         qvirtqueue_get_buf(s, q, &got_desc_idx, NULL)) {
 101                     g_assert_cmpint(got_desc_idx, ==, free_head);
 102                     break;
 103                 }
 104                 g_assert(g_get_monotonic_time() - start_time
 105                         <= QVIRTIO_NET_TIMEOUT_US);
 106
 107                 /* Run the main loop */
 108                 qtest_clock_step(s, 100);
 109                 flush_events(s);
 110             }
 111         }
 112         Data += vqa.length;
 113         Size -= vqa.length;
 114     }
 115 }
 116
 117 static void virtio_net_fork_fuzz(QTestState *s,
 118         const unsigned char *Data, size_t Size)
 119 {
 120     if (fork() == 0) {
 121         virtio_net_fuzz_multi(s, Data, Size, false);
 122         flush_events(s);
 123         _Exit(0);
 124     } else {
 125         flush_events(s);
 126         wait(NULL);
 127     }
 128 }
 129
 130 static void virtio_net_fork_fuzz_check_used(QTestState *s,
 131         const unsigned char *Data, size_t Size)
 132 {
 133     if (fork() == 0) {
 134         virtio_net_fuzz_multi(s, Data, Size, true);
 135         flush_events(s);
 136         _Exit(0);
 137     } else {
 138         flush_events(s);
 139         wait(NULL);
 140     }
 141 }
 142
 143 static void virtio_net_pre_fuzz(QTestState *s)
 144 {
 145     qos_init_path(s);
 146     counter_shm_init();
 147 }
 148
 149 static void *virtio_net_test_setup_socket(GString *cmd_line, void *arg)
 150 {
 151     int ret = socketpair(PF_UNIX, SOCK_STREAM, 0, sockfds);
 152     g_assert_cmpint(ret, !=, -1);
 153     fcntl(sockfds[0], F_SETFL, O_NONBLOCK);
 154     sockfds_initialized = true;
 155     g_string_append_printf(cmd_line, " -netdev socket,fd=%d,id=hs0 ",
 156                            sockfds[1]);
 157     return arg;
 158 }
 159
 160 static void *virtio_net_test_setup_user(GString *cmd_line, void *arg)
 161 {
 162     g_string_append_printf(cmd_line, " -netdev user,id=hs0 ");
 163     return arg;
 164 }
 165
 166 static void register_virtio_net_fuzz_targets(void)
 167 {
 168     fuzz_add_qos_target(&(FuzzTarget){
 169             .name = "virtio-net-socket",
 170             .description = "Fuzz the virtio-net virtual queues. Fuzz incoming "
 171             "traffic using the socket backend",
 172             .pre_fuzz = &virtio_net_pre_fuzz,
 173             .fuzz = virtio_net_fork_fuzz,},
 174             "virtio-net",
 175             &(QOSGraphTestOptions){.before = virtio_net_test_setup_socket}
 176             );
 177
 178     fuzz_add_qos_target(&(FuzzTarget){
 179             .name = "virtio-net-socket-check-used",
 180             .description = "Fuzz the virtio-net virtual queues. Wait for the "
 181             "descriptors to be used. Timeout may indicate improperly handled "
 182             "input",
 183             .pre_fuzz = &virtio_net_pre_fuzz,
 184             .fuzz = virtio_net_fork_fuzz_check_used,},
 185             "virtio-net",
 186             &(QOSGraphTestOptions){.before = virtio_net_test_setup_socket}
 187             );
 188     fuzz_add_qos_target(&(FuzzTarget){
 189             .name = "virtio-net-slirp",
 190             .description = "Fuzz the virtio-net virtual queues with the slirp "
 191             " backend. Warning: May result in network traffic emitted from the "
 192             " process. Run in an isolated network environment.",
 193             .pre_fuzz = &virtio_net_pre_fuzz,
 194             .fuzz = virtio_net_fork_fuzz,},
 195             "virtio-net",
 196             &(QOSGraphTestOptions){.before = virtio_net_test_setup_user}
 197             );
 198 }
 199
 200 fuzz_target_init(register_virtio_net_fuzz_targets);