asan.c

#include <darwintest.h>
#include <dlfcn.h>
#include <malloc/malloc.h>
#include <setjmp.h>
#include <stdlib.h>
#include "sanitizer/asan_interface.h"

T_GLOBAL_META(T_META_RUN_CONCURRENTLY(true));

T_DECL(asan_sanity, "ASan Sanity Check", T_META_CHECK_LEAKS(NO))
{
	const char *dylib_path =
		TARGET_OS_OSX    ? "@rpath/libclang_rt.asan_osx_dynamic.dylib" :
		TARGET_OS_IOS    ? "@rpath/libclang_rt.asan_ios_dynamic.dylib" :
		TARGET_OS_TV     ? "@rpath/libclang_rt.asan_tvos_dynamic.dylib" :
		TARGET_OS_WATCH  ? "@rpath/libclang_rt.asan_watchos_dynamic.dylib" :
		TARGET_OS_BRIDGE ? "@rpath/libclang_rt.asan_bridgeos_dynamic.dylib" :
		NULL;

	void *asan_dylib = dlopen(dylib_path, RTLD_NOLOAD);
	T_ASSERT_NOTNULL(asan_dylib, "ASan dylib loaded");

	void *ptr = malloc(16);
	free(ptr);
	
	T_PASS("I didn't crash!");
}

jmp_buf longjmp_env = {0};
bool asan_report_hit = false;
char *asan_report = NULL;

void asan_report_handler(const char *report) {
	asan_report_hit = true;
	asan_report = strdup(report);
	longjmp(longjmp_env, 1);
}

__attribute__((optnone, noinline))
void write_byte(void *ptr, size_t offset) {
	((char *)ptr)[offset] = 'x';
}

T_DECL(asan_use_after_free, "ASan Detects use-after-free", T_META_CHECK_LEAKS(NO))
{
	asan_report = NULL;
	asan_report_hit = false;
	__asan_set_error_report_callback(asan_report_handler);

	if (setjmp(longjmp_env) == 0) {
		char *ptr = malloc(16);
		free(ptr);
		write_byte(ptr, 10);

		T_FAIL("use-after-free not detected");
	}

	T_EXPECT_EQ(asan_report_hit, true, "asan finds use-after-free");
	T_EXPECT_NOTNULL(strstr(asan_report, "AddressSanitizer: heap-use-after-free"), "asan header");
}

T_DECL(asan_heap_buffer_overflow, "ASan Detects heap-buffer-overflow", T_META_CHECK_LEAKS(NO))
{
	asan_report = NULL;
	asan_report_hit = false;
	__asan_set_error_report_callback(asan_report_handler);

	if (setjmp(longjmp_env) == 0) {
		char *ptr = malloc(16);
		write_byte(ptr, 17);
		free(ptr);

		T_FAIL("heap-buffer-overflow not detected");
	}

	T_EXPECT_EQ(asan_report_hit, true, "asan finds heap-buffer-overflow");
	T_EXPECT_NOTNULL(strstr(asan_report, "AddressSanitizer: heap-buffer-overflow"), "asan header");
}

static malloc_zone_t *
call_malloc_zone_from_ptr(void)
{
	void *ptr = malloc(5);
	malloc_zone_t *zone = malloc_zone_from_ptr(ptr);
	free(ptr);
	return zone;
}

extern int32_t malloc_num_zones;
extern malloc_zone_t **malloc_zones;
T_DECL(asan_zone0, "Ensure we return the real zone 0 (not the virtual zone)")
{
	malloc_zone_t *zone0 = malloc_zones[0];
	T_EXPECT_EQ(malloc_default_zone(), zone0, NULL);
	T_EXPECT_EQ(call_malloc_zone_from_ptr(), zone0, NULL);
}

T_DECL(pgm_interaction, "Ensure we never enable PGM together with ASan",
		T_META_ENVVAR("MallocProbGuard=1"))
{
	for (uint32_t i = 0; i < malloc_num_zones; i++) {
		const char *zone_name = malloc_get_zone_name(malloc_zones[i]);
		T_QUIET; T_EXPECT_NE_STR(zone_name, "ProbGuardMallocZone", NULL);
	}
	T_PASS("No PGM zone installed");
}