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|
/*
+----------------------------------------------------------------------+
| Copyright (c) The PHP Group |
+----------------------------------------------------------------------+
| This source file is subject to version 3.01 of the PHP license, |
| that is bundled with this package in the file LICENSE, and is |
| available through the world-wide-web at the following url: |
| https://www.php.net/license/3_01.txt |
| If you did not receive a copy of the PHP license and are unable to |
| obtain it through the world-wide-web, please send a note to |
| license@php.net so we can mail you a copy immediately. |
+----------------------------------------------------------------------+
| Authors: Nikita Popov <nikic@php.net> |
+----------------------------------------------------------------------+
*/
#include <main/php.h>
#if defined(__FreeBSD__)
# include <sys/sysctl.h>
#endif
#include "fuzzer.h"
#include "fuzzer-sapi.h"
#include "zend_exceptions.h"
#define FILE_NAME "/tmp/fuzzer.php"
#define MAX_STEPS 1000
#define MAX_SIZE (8 * 1024)
static uint32_t steps_left;
static bool bailed_out = false;
/* Because the fuzzer is always compiled with clang,
* we can assume that we don't use global registers / hybrid VM. */
typedef int (ZEND_FASTCALL *opcode_handler_t)(zend_execute_data *);
static zend_always_inline void fuzzer_bailout(void) {
bailed_out = true;
zend_bailout();
}
static zend_always_inline void fuzzer_step(void) {
if (--steps_left == 0) {
/* Reset steps before bailing out, so code running after bailout (e.g. in
* destructors) will get another MAX_STEPS, rather than UINT32_MAX steps. */
steps_left = MAX_STEPS;
fuzzer_bailout();
}
}
static void (*orig_execute_ex)(zend_execute_data *execute_data);
static void fuzzer_execute_ex(zend_execute_data *execute_data) {
while (1) {
int ret;
fuzzer_step();
if ((ret = ((opcode_handler_t) EX(opline)->handler)(execute_data)) != 0) {
if (ret > 0) {
execute_data = EG(current_execute_data);
} else {
return;
}
}
}
}
static zend_op_array *(*orig_compile_string)(
zend_string *source_string, const char *filename, zend_compile_position position);
static zend_op_array *fuzzer_compile_string(
zend_string *str, const char *filename, zend_compile_position position) {
if (ZSTR_LEN(str) > MAX_SIZE) {
/* Avoid compiling huge inputs via eval(). */
fuzzer_bailout();
}
return orig_compile_string(str, filename, position);
}
static void (*orig_execute_internal)(zend_execute_data *execute_data, zval *return_value);
static void fuzzer_execute_internal(zend_execute_data *execute_data, zval *return_value) {
fuzzer_step();
uint32_t num_args = ZEND_CALL_NUM_ARGS(execute_data);
for (uint32_t i = 0; i < num_args; i++) {
/* Some internal functions like preg_replace() may be slow on large inputs.
* Limit the maximum size of string inputs. */
zval *arg = ZEND_CALL_VAR_NUM(execute_data, i);
if (Z_TYPE_P(arg) == IS_STRING && Z_STRLEN_P(arg) > MAX_SIZE) {
fuzzer_bailout();
}
}
orig_execute_internal(execute_data, return_value);
}
static void fuzzer_init_php_for_execute(const char *extra_ini) {
/* Compilation will often trigger fatal errors.
* Use tracked allocation mode to avoid leaks in that case. */
putenv("USE_TRACKED_ALLOC=1");
/* Just like other SAPIs, ignore SIGPIPEs. */
signal(SIGPIPE, SIG_IGN);
fuzzer_init_php(extra_ini);
orig_execute_ex = zend_execute_ex;
zend_execute_ex = fuzzer_execute_ex;
orig_execute_internal = zend_execute_internal ? zend_execute_internal : execute_internal;
zend_execute_internal = fuzzer_execute_internal;
orig_compile_string = zend_compile_string;
zend_compile_string = fuzzer_compile_string;
}
ZEND_ATTRIBUTE_UNUSED static void create_file(void) {
/* For opcache_invalidate() to work, the dummy file name used for fuzzing needs to
* actually exist. */
FILE *f = fopen(FILE_NAME, "w");
fclose(f);
}
ZEND_ATTRIBUTE_UNUSED static void opcache_invalidate(void) {
steps_left = MAX_STEPS;
zend_exception_save();
zval retval, func, args[2];
ZVAL_STRING(&func, "opcache_invalidate");
ZVAL_STRING(&args[0], FILE_NAME);
ZVAL_TRUE(&args[1]);
call_user_function(CG(function_table), NULL, &func, &retval, 2, args);
ZEND_ASSERT(Z_TYPE(retval) == IS_TRUE);
zval_ptr_dtor(&args[0]);
zval_ptr_dtor(&retval);
zval_ptr_dtor(&func);
zend_exception_restore();
}
ZEND_ATTRIBUTE_UNUSED char *get_opcache_path(void) {
/* Try relative to cwd. */
char *p = realpath("modules/opcache.so", NULL);
if (p) {
return p;
}
/* Try relative to binary location. */
char path[MAXPATHLEN];
#if defined(__FreeBSD__)
size_t pathlen = sizeof(path);
int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
if (sysctl(mib, 4, path, &pathlen, NULL, 0) < 0) {
#else
if (readlink("/proc/self/exe", path, sizeof(path)) < 0) {
#endif
ZEND_ASSERT(0 && "Failed to get binary path");
return NULL;
}
/* Get basename. */
char *last_sep = strrchr(path, '/');
if (last_sep) {
*last_sep = '\0';
}
strlcat(path, "/modules/opcache.so", sizeof(path));
return realpath(path, NULL);
}
|
