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authorAlexander Bulekov <alxndr@bu.edu>2020-02-19 23:11:16 -0500
committerStefan Hajnoczi <stefanha@redhat.com>2020-02-22 08:26:48 +0000
commitb1db8c63169f2139af9f26c884e5e2abd27dd290 (patch)
tree40834e804fa39fc2b8c2066dcfdf4379214f17c9
parent04f713242d1fdb9cc03c0bff76f0750f7c8903a0 (diff)
downloadqemu-arm-b1db8c63169f2139af9f26c884e5e2abd27dd290.tar.gz
fuzz: add virtio-net fuzz target
The virtio-net fuzz target feeds inputs to all three virtio-net virtqueues, and uses forking to avoid leaking state between fuzz runs. Signed-off-by: Alexander Bulekov <alxndr@bu.edu> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Darren Kenny <darren.kenny@oracle.com> Message-id: 20200220041118.23264-21-alxndr@bu.edu Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
-rw-r--r--tests/qtest/fuzz/Makefile.include1
-rw-r--r--tests/qtest/fuzz/virtio_net_fuzz.c198
2 files changed, 199 insertions, 0 deletions
diff --git a/tests/qtest/fuzz/Makefile.include b/tests/qtest/fuzz/Makefile.include
index 38b8cdd9f1..77385777ef 100644
--- a/tests/qtest/fuzz/Makefile.include
+++ b/tests/qtest/fuzz/Makefile.include
@@ -8,6 +8,7 @@ fuzz-obj-y += tests/qtest/fuzz/qos_fuzz.o
# Targets
fuzz-obj-y += tests/qtest/fuzz/i440fx_fuzz.o
+fuzz-obj-y += tests/qtest/fuzz/virtio_net_fuzz.o
FUZZ_CFLAGS += -I$(SRC_PATH)/tests -I$(SRC_PATH)/tests/qtest
diff --git a/tests/qtest/fuzz/virtio_net_fuzz.c b/tests/qtest/fuzz/virtio_net_fuzz.c
new file mode 100644
index 0000000000..d08a47e278
--- /dev/null
+++ b/tests/qtest/fuzz/virtio_net_fuzz.c
@@ -0,0 +1,198 @@
+/*
+ * 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/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) {
+ write(sockfds[0], Data, vqa.length);
+ } 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 {
+ 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 {
+ 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);