test: fuzz: Add framework for fuzzing

Add the basic infrastructure for declaring fuzz tests and a command to
invoke them.

Signed-off-by: Andrew Scull <ascull@google.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/Kconfig b/Kconfig
index 6b97a0236f8cc97f2be48d67bc44302547d64fe6..991b260182e8960c9ed4f560ee7993f2d489b739 100644 (file)
--- a/Kconfig
+++ b/Kconfig
@@ -161,6 +161,15 @@ config ASAN
          Enables AddressSanitizer to discover out-of-bounds accesses,
          use-after-free, double-free and memory leaks.
 
+config FUZZ
+       bool "Enable fuzzing"
+       depends on CC_IS_CLANG
+       depends on DM_FUZZING_ENGINE
+       select ASAN
+       help
+         Enables the fuzzing infrastructure to generate fuzzing data and run
+          fuzz tests.
+
 config CC_HAS_ASM_INLINE
        def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null)
 

diff --git a/include/test/fuzz.h b/include/test/fuzz.h
new file mode 100644 (file)
index 0000000..d4c5754
--- /dev/null
+++ b/include/test/fuzz.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (c) 2022 Google, Inc.
+ * Written by Andrew Scull <ascull@google.com>
+ */
+
+#ifndef __TEST_FUZZ_H
+#define __TEST_FUZZ_H
+
+#include <linker_lists.h>
+#include <linux/types.h>
+
+/**
+ * struct fuzz_test - Information about a fuzz test
+ *
+ * @name: Name of fuzz test
+ * @func: Function to call to perform fuzz test on an input
+ * @flags: Flags indicate pre-conditions for fuzz test
+ */
+struct fuzz_test {
+       const char *name;
+       int (*func)(const uint8_t * data, size_t size);
+       int flags;
+};
+
+/**
+ * FUZZ_TEST() - register a fuzz test
+ *
+ * The fuzz test function must return 0 as other values are reserved for future
+ * use.
+ *
+ * @_name:     the name of the fuzz test function
+ * @_flags:    an integer field that can be evaluated by the fuzzer
+ *             implementation
+ */
+#define FUZZ_TEST(_name, _flags)                                       \
+       ll_entry_declare(struct fuzz_test, _name, fuzz_tests) = {       \
+               .name = #_name,                                         \
+               .func = _name,                                          \
+               .flags = _flags,                                        \
+       }
+
+/** Get the start of the list of fuzz tests */
+#define FUZZ_TEST_START() \
+       ll_entry_start(struct fuzz_test, fuzz_tests)
+
+/** Get the number of elements in the list of fuzz tests */
+#define FUZZ_TEST_COUNT() \
+       ll_entry_count(struct fuzz_test, fuzz_tests)
+
+#endif /* __TEST_FUZZ_H */

diff --git a/test/Makefile b/test/Makefile
index abd605a4351e038b46be0f3485d8e74216e3bd45..1dfd5677440d734c00f1e82224778e6be6ec9b50 100644 (file)
--- a/test/Makefile
+++ b/test/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_$(SPL_)CMDLINE) += cmd_ut.o
 obj-$(CONFIG_$(SPL_)CMDLINE) += command_ut.o
 obj-$(CONFIG_$(SPL_)UT_COMPRESSION) += compression.o
 obj-y += dm/
+obj-$(CONFIG_FUZZ) += fuzz/
 obj-$(CONFIG_$(SPL_)CMDLINE) += print_ut.o
 obj-$(CONFIG_$(SPL_)CMDLINE) += str_ut.o
 obj-$(CONFIG_UT_TIME) += time_ut.o

diff --git a/test/fuzz/Makefile b/test/fuzz/Makefile
new file mode 100644 (file)
index 0000000..03eeeeb
--- /dev/null
+++ b/test/fuzz/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (c) 2022 Google, Inc.
+# Written by Andrew Scull <ascull@google.com>
+#
+
+obj-$(CONFIG_$(SPL_)CMDLINE) += cmd_fuzz.o

diff --git a/test/fuzz/cmd_fuzz.c b/test/fuzz/cmd_fuzz.c
new file mode 100644 (file)
index 0000000..0cc01dc
--- /dev/null
+++ b/test/fuzz/cmd_fuzz.c
@@ -0,0 +1,82 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (c) 2022 Google, Inc.
+ * Written by Andrew Scull <ascull@google.com>
+ */
+
+#include <command.h>
+#include <common.h>
+#include <dm.h>
+#include <fuzzing_engine.h>
+#include <test/fuzz.h>
+
+static struct fuzz_test *find_fuzz_test(const char *name)
+{
+       struct fuzz_test *fuzzer = FUZZ_TEST_START();
+       size_t count = FUZZ_TEST_COUNT();
+       size_t i;
+
+       for (i = 0; i < count; ++i) {
+               if (strcmp(name, fuzzer->name) == 0)
+                       return fuzzer;
+               ++fuzzer;
+       }
+
+       return NULL;
+}
+
+static struct udevice *find_fuzzing_engine(void)
+{
+       struct udevice *dev;
+
+       if (uclass_first_device(UCLASS_FUZZING_ENGINE, &dev))
+               return NULL;
+
+       return dev;
+}
+
+static int do_fuzz(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
+{
+       struct fuzz_test *fuzzer;
+       struct udevice *dev;
+
+       if (argc != 2)
+               return CMD_RET_USAGE;
+
+       fuzzer = find_fuzz_test(argv[1]);
+       if (!fuzzer) {
+               printf("Could not find fuzzer: %s\n", argv[1]);
+               return 1;
+       }
+
+       dev = find_fuzzing_engine();
+       if (!dev) {
+               puts("No fuzzing engine available\n");
+               return 1;
+       }
+
+       while (1) {
+               const uint8_t *data;
+               size_t size;
+
+               if (dm_fuzzing_engine_get_input(dev, &data, &size)) {
+                       puts("Fuzzing engine failed\n");
+                       return 1;
+               }
+
+               fuzzer->func(data, size);
+       }
+
+       return 1;
+}
+
+#ifdef CONFIG_SYS_LONGHELP
+static char fuzz_help_text[] =
+       "[fuzz-test-name] - execute the named fuzz test\n"
+       ;
+#endif /* CONFIG_SYS_LONGHELP */
+
+U_BOOT_CMD(
+       fuzz, CONFIG_SYS_MAXARGS, 1, do_fuzz,
+       "fuzz tests", fuzz_help_text
+);