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 | http://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 ",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 if (php_module_startup(sapi_module, NULL, 0)==FAILURE) {
66 return FAILURE;
67 }
68 return SUCCESS;
69 }
70
ub_write(const char * str,size_t str_length)71 static size_t ub_write(const char *str, size_t str_length)
72 {
73 /* quiet */
74 return str_length;
75 }
76
fuzzer_flush(void * server_context)77 static void fuzzer_flush(void *server_context)
78 {
79 /* quiet */
80 }
81
send_header(sapi_header_struct * sapi_header,void * server_context)82 static void send_header(sapi_header_struct *sapi_header, void *server_context)
83 {
84 }
85
read_cookies()86 static char* read_cookies()
87 {
88 /* TODO: fuzz these! */
89 return NULL;
90 }
91
register_variables(zval * track_vars_array)92 static void register_variables(zval *track_vars_array)
93 {
94 php_import_environment_variables(track_vars_array);
95 }
96
log_message(const char * message,int level)97 static void log_message(const char *message, int level)
98 {
99 }
100
101
102 static sapi_module_struct fuzzer_module = {
103 "fuzzer", /* name */
104 "clang fuzzer", /* pretty name */
105
106 startup, /* startup */
107 php_module_shutdown_wrapper, /* shutdown */
108
109 NULL, /* activate */
110 NULL, /* deactivate */
111
112 ub_write, /* unbuffered write */
113 fuzzer_flush, /* flush */
114 NULL, /* get uid */
115 NULL, /* getenv */
116
117 php_error, /* error handler */
118
119 NULL, /* header handler */
120 NULL, /* send headers handler */
121 send_header, /* send header handler */
122
123 NULL, /* read POST data */
124 read_cookies, /* read Cookies */
125
126 register_variables, /* register server variables */
127 log_message, /* Log message */
128 NULL, /* Get request time */
129 NULL, /* Child terminate */
130
131 STANDARD_SAPI_MODULE_PROPERTIES
132 };
133
fuzzer_init_php()134 int fuzzer_init_php()
135 {
136 #ifdef __SANITIZE_ADDRESS__
137 /* We're going to leak all the memory allocated during startup,
138 * so disable lsan temporarily. */
139 __lsan_disable();
140 #endif
141
142 sapi_startup(&fuzzer_module);
143 fuzzer_module.phpinfo_as_text = 1;
144
145 fuzzer_module.ini_entries = malloc(sizeof(HARDCODED_INI));
146 memcpy(fuzzer_module.ini_entries, HARDCODED_INI, sizeof(HARDCODED_INI));
147
148 /*
149 * TODO: we might want to test both Zend and malloc MM, but testing with malloc
150 * is more likely to find bugs, so use that for now.
151 */
152 putenv("USE_ZEND_ALLOC=0");
153
154 if (fuzzer_module.startup(&fuzzer_module)==FAILURE) {
155 return FAILURE;
156 }
157
158 #ifdef __SANITIZE_ADDRESS__
159 __lsan_enable();
160 #endif
161
162 return SUCCESS;
163 }
164
fuzzer_request_startup()165 int fuzzer_request_startup()
166 {
167 if (php_request_startup() == FAILURE) {
168 php_module_shutdown();
169 return FAILURE;
170 }
171
172 #ifdef ZEND_SIGNALS
173 /* Some signal handlers will be overridden,
174 * don't complain about them during shutdown. */
175 SIGG(check) = 0;
176 #endif
177
178 return SUCCESS;
179 }
180
fuzzer_request_shutdown()181 void fuzzer_request_shutdown()
182 {
183 zend_try {
184 /* Destroy thrown exceptions. This does not happen as part of request shutdown. */
185 if (EG(exception)) {
186 zend_object_release(EG(exception));
187 EG(exception) = NULL;
188 }
189
190 /* Some fuzzers (like unserialize) may create circular structures. Make sure we free them.
191 * Two calls are performed to handle objects with destructors. */
192 zend_gc_collect_cycles();
193 zend_gc_collect_cycles();
194 } zend_end_try();
195
196 php_request_shutdown(NULL);
197 }
198
199 /* Set up a dummy stack frame so that exceptions may be thrown. */
fuzzer_setup_dummy_frame()200 void fuzzer_setup_dummy_frame()
201 {
202 static zend_execute_data execute_data;
203 static zend_function func;
204
205 memset(&execute_data, 0, sizeof(zend_execute_data));
206 memset(&func, 0, sizeof(zend_function));
207
208 func.type = ZEND_INTERNAL_FUNCTION;
209 func.common.function_name = ZSTR_EMPTY_ALLOC();
210 execute_data.func = &func;
211 EG(current_execute_data) = &execute_data;
212 }
213
fuzzer_set_ini_file(const char * file)214 void fuzzer_set_ini_file(const char *file)
215 {
216 if (fuzzer_module.php_ini_path_override) {
217 free(fuzzer_module.php_ini_path_override);
218 }
219 fuzzer_module.php_ini_path_override = strdup(file);
220 }
221
222
fuzzer_shutdown_php()223 int fuzzer_shutdown_php()
224 {
225 php_module_shutdown();
226 sapi_shutdown();
227
228 free(fuzzer_module.ini_entries);
229 return SUCCESS;
230 }
231
fuzzer_do_request_from_buffer(char * filename,const char * data,size_t data_len,zend_bool execute)232 int fuzzer_do_request_from_buffer(
233 char *filename, const char *data, size_t data_len, zend_bool execute)
234 {
235 int retval = FAILURE; /* failure by default */
236
237 SG(options) |= SAPI_OPTION_NO_CHDIR;
238 SG(request_info).argc=0;
239 SG(request_info).argv=NULL;
240
241 if (fuzzer_request_startup() == FAILURE) {
242 return FAILURE;
243 }
244
245 // Commented out to avoid leaking the header callback.
246 //SG(headers_sent) = 1;
247 //SG(request_info).no_headers = 1;
248 php_register_variable("PHP_SELF", filename, NULL);
249
250 zend_first_try {
251 zend_file_handle file_handle;
252 zend_stream_init_filename(&file_handle, filename);
253 file_handle.buf = estrndup(data, data_len);
254 file_handle.len = data_len;
255
256 zend_op_array *op_array = zend_compile_file(&file_handle, ZEND_REQUIRE);
257 if (op_array) {
258 if (execute) {
259 zend_execute(op_array, NULL);
260 }
261 destroy_op_array(op_array);
262 efree(op_array);
263 }
264 } zend_end_try();
265
266 CG(compiled_filename) = NULL; /* ??? */
267 fuzzer_request_shutdown();
268
269 return (retval == SUCCESS) ? SUCCESS : FAILURE;
270 }
271
272 // Call named PHP function with N zval arguments
fuzzer_call_php_func_zval(const char * func_name,int nargs,zval * args)273 void fuzzer_call_php_func_zval(const char *func_name, int nargs, zval *args) {
274 zval retval, func;
275
276 ZVAL_STRING(&func, func_name);
277 ZVAL_UNDEF(&retval);
278 call_user_function(CG(function_table), NULL, &func, &retval, nargs, args);
279
280 // TODO: check result?
281 /* to ensure retval is not broken */
282 php_var_dump(&retval, 0);
283
284 /* cleanup */
285 zval_ptr_dtor(&retval);
286 zval_ptr_dtor(&func);
287 }
288
289 // Call named PHP function with N string arguments
fuzzer_call_php_func(const char * func_name,int nargs,char ** params)290 void fuzzer_call_php_func(const char *func_name, int nargs, char **params) {
291 zval args[nargs];
292 int i;
293
294 for(i=0;i<nargs;i++) {
295 ZVAL_STRING(&args[i], params[i]);
296 }
297
298 fuzzer_call_php_func_zval(func_name, nargs, args);
299
300 for(i=0;i<nargs;i++) {
301 zval_ptr_dtor(&args[i]);
302 ZVAL_UNDEF(&args[i]);
303 }
304 }
305
