1 /*
2 +----------------------------------------------------------------------+
3 | Copyright (c) The PHP Group |
4 +----------------------------------------------------------------------+
5 | This source file is subject to version 3.01 of the PHP license, |
6 | that is bundled with this package in the file LICENSE, and is |
7 | available through the world-wide-web at the following url: |
8 | https://www.php.net/license/3_01.txt |
9 | If you did not receive a copy of the PHP license and are unable to |
10 | obtain it through the world-wide-web, please send a note to |
11 | license@php.net so we can mail you a copy immediately. |
12 +----------------------------------------------------------------------+
13 | Authors: Johannes Schlüter <johanes@php.net> |
14 | Stanislav Malyshev <stas@php.net> |
15 +----------------------------------------------------------------------+
16 */
17
18 #include <main/php.h>
19 #include <main/php_main.h>
20 #include <main/SAPI.h>
21 #include <ext/standard/info.h>
22 #include <ext/standard/php_var.h>
23 #include <main/php_variables.h>
24 #include <zend_exceptions.h>
25
26 #ifdef __SANITIZE_ADDRESS__
27 # include "sanitizer/lsan_interface.h"
28 #endif
29
30 #include "fuzzer.h"
31 #include "fuzzer-sapi.h"
32
33 const char HARDCODED_INI[] =
34 "html_errors=0\n"
35 "implicit_flush=1\n"
36 "output_buffering=0\n"
37 "error_reporting=0\n"
38 /* Let the timeout be enforced by libfuzzer, not PHP. */
39 "max_execution_time=0\n"
40 /* Reduce oniguruma limits to speed up fuzzing */
41 "mbstring.regex_stack_limit=10000\n"
42 "mbstring.regex_retry_limit=10000\n"
43 /* For the "execute" fuzzer disable some functions that are likely to have
44 * undesirable consequences (shell execution, file system writes). */
45 "allow_url_include=0\n"
46 "allow_url_fopen=0\n"
47 "open_basedir=/tmp\n"
48 "disable_functions=dl,mail,mb_send_mail"
49 ",shell_exec,exec,system,proc_open,popen,passthru,pcntl_exec"
50 ",chdir,chgrp,chmod,chown,copy,file_put_contents,lchgrp,lchown,link,mkdir"
51 ",move_uploaded_file,rename,rmdir,symlink,tempname,touch,unlink,fopen"
52 /* Networking code likes to wait and wait. */
53 ",fsockopen,pfsockopen"
54 ",stream_socket_pair,stream_socket_client,stream_socket_server"
55 /* crypt() can be very slow. */
56 ",crypt"
57 /* openlog() has a known memory-management issue. */
58 ",openlog"
59 /* Can cause long loops that bypass the executor step limit. */
60 "\ndisable_classes=InfiniteIterator"
61 ;
62
startup(sapi_module_struct * sapi_module)63 static int startup(sapi_module_struct *sapi_module)
64 {
65 return php_module_startup(sapi_module, NULL);
66 }
67
ub_write(const char * str,size_t str_length)68 static size_t ub_write(const char *str, size_t str_length)
69 {
70 /* quiet */
71 return str_length;
72 }
73
fuzzer_flush(void * server_context)74 static void fuzzer_flush(void *server_context)
75 {
76 /* quiet */
77 }
78
send_header(sapi_header_struct * sapi_header,void * server_context)79 static void send_header(sapi_header_struct *sapi_header, void *server_context)
80 {
81 }
82
read_cookies(void)83 static char* read_cookies(void)
84 {
85 /* TODO: fuzz these! */
86 return NULL;
87 }
88
register_variables(zval * track_vars_array)89 static void register_variables(zval *track_vars_array)
90 {
91 php_import_environment_variables(track_vars_array);
92 }
93
log_message(const char * message,int level)94 static void log_message(const char *message, int level)
95 {
96 }
97
98
99 static sapi_module_struct fuzzer_module = {
100 "fuzzer", /* name */
101 "clang fuzzer", /* pretty name */
102
103 startup, /* startup */
104 php_module_shutdown_wrapper, /* shutdown */
105
106 NULL, /* activate */
107 NULL, /* deactivate */
108
109 ub_write, /* unbuffered write */
110 fuzzer_flush, /* flush */
111 NULL, /* get uid */
112 NULL, /* getenv */
113
114 php_error, /* error handler */
115
116 NULL, /* header handler */
117 NULL, /* send headers handler */
118 send_header, /* send header handler */
119
120 NULL, /* read POST data */
121 read_cookies, /* read Cookies */
122
123 register_variables, /* register server variables */
124 log_message, /* Log message */
125 NULL, /* Get request time */
126 NULL, /* Child terminate */
127
128 STANDARD_SAPI_MODULE_PROPERTIES
129 };
130
fuzzer_init_php(const char * extra_ini)131 int fuzzer_init_php(const char *extra_ini)
132 {
133 #ifdef __SANITIZE_ADDRESS__
134 /* We're going to leak all the memory allocated during startup,
135 * so disable lsan temporarily. */
136 __lsan_disable();
137 #endif
138
139 sapi_startup(&fuzzer_module);
140 fuzzer_module.phpinfo_as_text = 1;
141
142 size_t ini_len = sizeof(HARDCODED_INI);
143 size_t extra_ini_len = extra_ini ? strlen(extra_ini) : 0;
144 if (extra_ini) {
145 ini_len += extra_ini_len + 1;
146 }
147 char *p = malloc(ini_len + 1);
148 fuzzer_module.ini_entries = p;
149 p = zend_mempcpy(p, HARDCODED_INI, sizeof(HARDCODED_INI) - 1);
150 if (extra_ini) {
151 *p++ = '\n';
152 p = zend_mempcpy(p, extra_ini, extra_ini_len);
153 }
154 *p = '\0';
155
156 /*
157 * TODO: we might want to test both Zend and malloc MM, but testing with malloc
158 * is more likely to find bugs, so use that for now.
159 */
160 putenv("USE_ZEND_ALLOC=0");
161
162 if (fuzzer_module.startup(&fuzzer_module)==FAILURE) {
163 return FAILURE;
164 }
165
166 #ifdef __SANITIZE_ADDRESS__
167 __lsan_enable();
168 #endif
169
170 return SUCCESS;
171 }
172
fuzzer_request_startup(void)173 int fuzzer_request_startup(void)
174 {
175 if (php_request_startup() == FAILURE) {
176 php_module_shutdown();
177 return FAILURE;
178 }
179
180 #ifdef ZEND_SIGNALS
181 /* Some signal handlers will be overridden,
182 * don't complain about them during shutdown. */
183 SIGG(check) = 0;
184 #endif
185
186 return SUCCESS;
187 }
188
fuzzer_request_shutdown(void)189 void fuzzer_request_shutdown(void)
190 {
191 zend_try {
192 /* Destroy thrown exceptions. This does not happen as part of request shutdown. */
193 if (EG(exception)) {
194 zend_object_release(EG(exception));
195 EG(exception) = NULL;
196 }
197
198 /* Some fuzzers (like unserialize) may create circular structures. Make sure we free them.
199 * Two calls are performed to handle objects with destructors. */
200 zend_gc_collect_cycles();
201 zend_gc_collect_cycles();
202 } zend_end_try();
203
204 php_request_shutdown(NULL);
205 }
206
207 /* Set up a dummy stack frame so that exceptions may be thrown. */
fuzzer_setup_dummy_frame(void)208 void fuzzer_setup_dummy_frame(void)
209 {
210 static zend_execute_data execute_data;
211 static zend_function func;
212
213 memset(&execute_data, 0, sizeof(zend_execute_data));
214 memset(&func, 0, sizeof(zend_function));
215
216 func.type = ZEND_INTERNAL_FUNCTION;
217 func.common.function_name = ZSTR_EMPTY_ALLOC();
218 execute_data.func = &func;
219 EG(current_execute_data) = &execute_data;
220 }
221
fuzzer_set_ini_file(const char * file)222 void fuzzer_set_ini_file(const char *file)
223 {
224 if (fuzzer_module.php_ini_path_override) {
225 free(fuzzer_module.php_ini_path_override);
226 }
227 fuzzer_module.php_ini_path_override = strdup(file);
228 }
229
230
fuzzer_shutdown_php(void)231 int fuzzer_shutdown_php(void)
232 {
233 php_module_shutdown();
234 sapi_shutdown();
235
236 free((void *)fuzzer_module.ini_entries);
237 return SUCCESS;
238 }
239
fuzzer_do_request_from_buffer(char * filename,const char * data,size_t data_len,bool execute,void (* before_shutdown)(void))240 int fuzzer_do_request_from_buffer(
241 char *filename, const char *data, size_t data_len, bool execute,
242 void (*before_shutdown)(void))
243 {
244 int retval = FAILURE; /* failure by default */
245
246 SG(options) |= SAPI_OPTION_NO_CHDIR;
247 SG(request_info).argc=0;
248 SG(request_info).argv=NULL;
249
250 if (fuzzer_request_startup() == FAILURE) {
251 return FAILURE;
252 }
253
254 // Commented out to avoid leaking the header callback.
255 //SG(headers_sent) = 1;
256 //SG(request_info).no_headers = 1;
257 php_register_variable("PHP_SELF", filename, NULL);
258
259 zend_first_try {
260 zend_file_handle file_handle;
261 zend_stream_init_filename(&file_handle, filename);
262 file_handle.primary_script = 1;
263 file_handle.buf = emalloc(data_len + ZEND_MMAP_AHEAD);
264 memcpy(file_handle.buf, data, data_len);
265 memset(file_handle.buf + data_len, 0, ZEND_MMAP_AHEAD);
266 file_handle.len = data_len;
267 /* Avoid ZEND_HANDLE_FILENAME for opcache. */
268 file_handle.type = ZEND_HANDLE_STREAM;
269
270 zend_op_array *op_array = zend_compile_file(&file_handle, ZEND_REQUIRE);
271 zend_destroy_file_handle(&file_handle);
272 if (op_array) {
273 if (execute) {
274 zend_execute(op_array, NULL);
275 }
276 zend_destroy_static_vars(op_array);
277 destroy_op_array(op_array);
278 efree(op_array);
279 }
280 } zend_end_try();
281
282 CG(compiled_filename) = NULL; /* ??? */
283 if (before_shutdown) {
284 zend_try {
285 before_shutdown();
286 } zend_end_try();
287 }
288 fuzzer_request_shutdown();
289
290 return (retval == SUCCESS) ? SUCCESS : FAILURE;
291 }
292
293 // Call named PHP function with N zval arguments
fuzzer_call_php_func_zval(const char * func_name,int nargs,zval * args)294 void fuzzer_call_php_func_zval(const char *func_name, int nargs, zval *args) {
295 zval retval, func;
296
297 ZVAL_STRING(&func, func_name);
298 ZVAL_UNDEF(&retval);
299 call_user_function(CG(function_table), NULL, &func, &retval, nargs, args);
300
301 // TODO: check result?
302 /* to ensure retval is not broken */
303 php_var_dump(&retval, 0);
304
305 /* cleanup */
306 zval_ptr_dtor(&retval);
307 zval_ptr_dtor(&func);
308 }
309
310 // Call named PHP function with N string arguments
fuzzer_call_php_func(const char * func_name,int nargs,char ** params)311 void fuzzer_call_php_func(const char *func_name, int nargs, char **params) {
312 zval args[nargs];
313 int i;
314
315 for(i=0;i<nargs;i++) {
316 ZVAL_STRING(&args[i], params[i]);
317 }
318
319 fuzzer_call_php_func_zval(func_name, nargs, args);
320
321 for(i=0;i<nargs;i++) {
322 zval_ptr_dtor(&args[i]);
323 ZVAL_UNDEF(&args[i]);
324 }
325 }
326
