tests/fuzz/fuzz.c serves as the entry point for the virtual-device
fuzzer. Namely, libfuzzer invokes the LLVMFuzzerInitialize and
LLVMFuzzerTestOneInput functions, both of which are defined in this
file. This change adds a "FuzzTarget" struct, along with the
fuzz_add_target function, which should be used to define new fuzz
targets.
Signed-off-by: Alexander Oleinik <alx...@bu.edu>
---
tests/fuzz/Makefile.include | 4 +-
tests/fuzz/fuzz.c | 179 ++++++++++++++++++++++++++++++++++++
tests/fuzz/fuzz.h | 30 ++++++
3 files changed, 211 insertions(+), 2 deletions(-)
create mode 100644 tests/fuzz/fuzz.c
create mode 100644 tests/fuzz/fuzz.h
diff --git a/tests/fuzz/Makefile.include b/tests/fuzz/Makefile.include
index 324e6c1433..b415b056b0 100644
--- a/tests/fuzz/Makefile.include
+++ b/tests/fuzz/Makefile.include
@@ -1,4 +1,4 @@
-# QEMU_PROG_FUZZ=qemu-fuzz-$(TARGET_NAME)$(EXESUF)
+QEMU_PROG_FUZZ=qemu-fuzz-$(TARGET_NAME)$(EXESUF)
fuzz-obj-y = $(libqos-obj-y)
fuzz-obj-y += tests/libqtest.o
-
+fuzz-obj-y += tests/fuzz/fuzz.o
diff --git a/tests/fuzz/fuzz.c b/tests/fuzz/fuzz.c
new file mode 100644
index 0000000000..833f436731
--- /dev/null
+++ b/tests/fuzz/fuzz.c
@@ -0,0 +1,179 @@
+#include "qemu/osdep.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+
+#include "tests/libqtest.h"
+#include "sysemu/qtest.h"
+#include "fuzz.h"
+#include "tests/libqos/qgraph.h"
+#include "sysemu/runstate.h"
+#include "sysemu/sysemu.h"
+
+typedef struct FuzzTargetState {
+ FuzzTarget *target;
+ QSLIST_ENTRY(FuzzTargetState) target_list;
+} FuzzTargetState;
+
+typedef QSLIST_HEAD(, FuzzTargetState) FuzzTargetList;
+
+static const char *fuzz_arch = TARGET_NAME;
+
+static FuzzTargetList *fuzz_target_list;
+static FuzzTarget *fuzz_target;
+static QTestState *fuzz_qts;
+static bool trace;
+
+
+void set_fuzz_target_args(int argc, char **argv)
+{
+ if (fuzz_target) {
+ fuzz_target->main_argc = argc;
+ fuzz_target->main_argv = argv;
+ }
+}
+
+void reboot(QTestState *s)
+{
+ qemu_system_reset(SHUTDOWN_CAUSE_GUEST_RESET);
+}
+
+static QTestState *qtest_setup(void)
+{
+ qtest_server_set_tx_handler(&qtest_client_inproc_recv, NULL);
+ return qtest_inproc_init(trace, fuzz_arch, &qtest_server_inproc_recv);
+}
+
+void fuzz_add_target(const char *name, const char *description,
+ FuzzTarget *target)
+{
+ FuzzTargetState *tmp;
+ FuzzTargetState *target_state;
+ if (!fuzz_target_list) {
+ fuzz_target_list = g_new0(FuzzTargetList, 1);
+ }
+
+ QSLIST_FOREACH(tmp, fuzz_target_list, target_list) {
+ if (g_strcmp0(tmp->target->name->str, name) == 0) {
+ fprintf(stderr, "Error: Fuzz target name %s already in use\n",
+ name);
+ abort();
+ }
+ }
+ target_state = g_new0(FuzzTargetState, 1);
+ target_state->target = g_new0(FuzzTarget, 1);
+ *(target_state->target) = *target;
+ target_state->target->name = g_string_new(name);
+ target_state->target->description = g_string_new(description);
+ QSLIST_INSERT_HEAD(fuzz_target_list, target_state, target_list);
+}
+
+
+static FuzzTarget *fuzz_get_target(char* name)
+{
+ FuzzTargetState *tmp;
+ if (!fuzz_target_list) {
+ fprintf(stderr, "Fuzz target list not initialized\n");
+ abort();
+ }
+
+ QSLIST_FOREACH(tmp, fuzz_target_list, target_list) {
+ if (g_strcmp0(tmp->target->name->str, name) == 0) {
+ break;
+ }
+ }
+ return tmp->target;
+}
+
+
+static void usage(char *path)
+{
+ printf("Usage: %s --FUZZ_TARGET [LIBFUZZER ARGUMENTS]\n", path);
+ printf("where --FUZZ_TARGET is one of:\n");
+ FuzzTargetState *tmp;
+ if (!fuzz_target_list) {
+ fprintf(stderr, "Fuzz target list not initialized\n");
+ abort();
+ }
+ QSLIST_FOREACH(tmp, fuzz_target_list, target_list) {
+ printf(" --%s : %s\n", tmp->target->name->str,
+ tmp->target->description->str);
+ }
+ exit(0);
+}
+
+
+/* Executed for each fuzzing-input */
+int LLVMFuzzerTestOneInput(const unsigned char *Data, size_t Size)
+{
+ if (fuzz_target->fuzz) {
+ fuzz_target->fuzz(fuzz_qts, Data, Size);
+ }
+ return 0;
+}
+
+/* Executed once, prior to fuzzing */
+int LLVMFuzzerInitialize(int *argc, char ***argv, char ***envp)
+{
+
+ char *target_name, *trace_qtest;
+
+ /* --trace is useful for outputting a log of qtest commands that trigger
+ * a crash. The log can can then be replayed with a simple qtest script. */
+ if (*argc > 2) {
+ trace_qtest = (*argv)[2];
+ if (strcmp(trace_qtest, "--trace") == 0) {
+ trace = true;
+ }
+ }
+
+ /* Initialize qgraph and modules */
+ qos_graph_init();
+ module_call_init(MODULE_INIT_FUZZ_TARGET);
+ module_call_init(MODULE_INIT_QOM);
+ module_call_init(MODULE_INIT_LIBQOS);
+
+ if (*argc <= 1) {
+ usage(**argv);
+ }
+
+ /* Identify the fuzz target */
+ target_name = (*argv)[1];
+ target_name += 2;
+ fuzz_target = fuzz_get_target(target_name);
+
+ fuzz_qts = qtest_setup(void);
+
+ if (!fuzz_target) {
+ fprintf(stderr, "Error: Fuzz fuzz_target name %s not found\n",
+ target_name);
+ usage(**argv);
+ }
+
+ if (fuzz_target->pre_main) {
+ fuzz_target->pre_main();
+ }
+
+ if (trace) {
+ printf("### cmd_line: ");
+ for (int i = 0; i < (fuzz_target->main_argc); i++) {
+ printf("%s ", ((fuzz_target->main_argv))[i]);
+ }
+ printf("\n");
+ }
+
+ /* Run QEMU's softmmu main with the calculated arguments*/
+ qemu_init(fuzz_target->main_argc, fuzz_target->main_argv, NULL);
+
+ /* If configured, this is a good spot to set up snapshotting */
+ if (fuzz_target->pre_fuzz) {
+ fuzz_target->pre_fuzz(fuzz_qts);
+ }
+
+ if (trace) {
+ printf("### END INITIALIZATION\n");
+ }
+
+ return 0;
+}
diff --git a/tests/fuzz/fuzz.h b/tests/fuzz/fuzz.h
new file mode 100644
index 0000000000..73af029c82
--- /dev/null
+++ b/tests/fuzz/fuzz.h
@@ -0,0 +1,30 @@
+#ifndef FUZZER_H_
+#define FUZZER_H_
+
+#include "qemu/osdep.h"
+#include "qemu/units.h"
+#include "qapi/error.h"
+#include "exec/memory.h"
+#include "tests/libqtest.h"
+
+
+typedef struct FuzzTarget {
+ GString *name;
+ GString *description;
+ void(*pre_main)(void);
+ void(*pre_fuzz)(QTestState *);
+ void(*fuzz)(QTestState *, const unsigned char *, size_t);
+ int main_argc;
+ char **main_argv;
+} FuzzTarget;
+
+void set_fuzz_target_args(int argc, char **argv);
+void reboot(QTestState *);
+void fuzz_add_target(const char *name, const char *description, FuzzTarget
+ *target);
+
+int LLVMFuzzerTestOneInput(const unsigned char *Data, size_t Size);
+int LLVMFuzzerInitialize(int *argc, char ***argv, char ***envp);
+
+#endif
+
--
2.23.0
