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 | Author: Rasmus Lerdorf <rasmus@php.net> |
14 | Ilia Alshanetsky <iliaa@php.net> |
15 +----------------------------------------------------------------------+
16 */
17
18 #include <stdio.h>
19 #include "php.h"
20 #include <ctype.h>
21 #include "php_string.h"
22 #include "ext/standard/head.h"
23 #include "ext/standard/file.h"
24 #include "basic_functions.h"
25 #include "exec.h"
26 #include "php_globals.h"
27 #include "SAPI.h"
28
29 #ifdef HAVE_SYS_WAIT_H
30 #include <sys/wait.h>
31 #endif
32
33 #include <signal.h>
34
35 #ifdef HAVE_SYS_TYPES_H
36 #include <sys/types.h>
37 #endif
38 #ifdef HAVE_SYS_STAT_H
39 #include <sys/stat.h>
40 #endif
41 #ifdef HAVE_FCNTL_H
42 #include <fcntl.h>
43 #endif
44
45 #ifdef HAVE_UNISTD_H
46 #include <unistd.h>
47 #endif
48
49 #include <limits.h>
50
51 #ifdef PHP_WIN32
52 # include "win32/nice.h"
53 #endif
54
55 static size_t cmd_max_len;
56
57 /* {{{ PHP_MINIT_FUNCTION(exec) */
PHP_MINIT_FUNCTION(exec)58 PHP_MINIT_FUNCTION(exec)
59 {
60 #ifdef _SC_ARG_MAX
61 cmd_max_len = sysconf(_SC_ARG_MAX);
62 if ((size_t)-1 == cmd_max_len) {
63 #ifdef _POSIX_ARG_MAX
64 cmd_max_len = _POSIX_ARG_MAX;
65 #else
66 cmd_max_len = 4096;
67 #endif
68 }
69 #elif defined(ARG_MAX)
70 cmd_max_len = ARG_MAX;
71 #elif defined(PHP_WIN32)
72 /* Executed commands will run through cmd.exe. As long as it's the case,
73 it's just the constant limit.*/
74 cmd_max_len = 8192;
75 #else
76 /* This is just an arbitrary value for the fallback case. */
77 cmd_max_len = 4096;
78 #endif
79
80 return SUCCESS;
81 }
82 /* }}} */
83
strip_trailing_whitespace(char * buf,size_t bufl)84 static size_t strip_trailing_whitespace(char *buf, size_t bufl) {
85 size_t l = bufl;
86 while (l-- > 0 && isspace(((unsigned char *)buf)[l]));
87 if (l != (bufl - 1)) {
88 bufl = l + 1;
89 buf[bufl] = '\0';
90 }
91 return bufl;
92 }
93
handle_line(int type,zval * array,char * buf,size_t bufl)94 static size_t handle_line(int type, zval *array, char *buf, size_t bufl) {
95 if (type == 1) {
96 PHPWRITE(buf, bufl);
97 if (php_output_get_level() < 1) {
98 sapi_flush();
99 }
100 } else if (type == 2) {
101 bufl = strip_trailing_whitespace(buf, bufl);
102 add_next_index_stringl(array, buf, bufl);
103 }
104 return bufl;
105 }
106
107 /* {{{ php_exec
108 * If type==0, only last line of output is returned (exec)
109 * If type==1, all lines will be printed and last lined returned (system)
110 * If type==2, all lines will be saved to given array (exec with &$array)
111 * If type==3, output will be printed binary, no lines will be saved or returned (passthru)
112 *
113 */
php_exec(int type,const char * cmd,zval * array,zval * return_value)114 PHPAPI int php_exec(int type, const char *cmd, zval *array, zval *return_value)
115 {
116 FILE *fp;
117 char *buf;
118 int pclose_return;
119 char *b, *d=NULL;
120 php_stream *stream;
121 size_t buflen, bufl = 0;
122 #if PHP_SIGCHILD
123 void (*sig_handler)() = NULL;
124 #endif
125
126 #if PHP_SIGCHILD
127 sig_handler = signal (SIGCHLD, SIG_DFL);
128 #endif
129
130 #ifdef PHP_WIN32
131 fp = VCWD_POPEN(cmd, "rb");
132 #else
133 fp = VCWD_POPEN(cmd, "r");
134 #endif
135 if (!fp) {
136 php_error_docref(NULL, E_WARNING, "Unable to fork [%s]", cmd);
137 goto err;
138 }
139
140 stream = php_stream_fopen_from_pipe(fp, "rb");
141
142 buf = (char *) emalloc(EXEC_INPUT_BUF);
143 buflen = EXEC_INPUT_BUF;
144
145 if (type != 3) {
146 b = buf;
147
148 while (php_stream_get_line(stream, b, EXEC_INPUT_BUF, &bufl)) {
149 /* no new line found, let's read some more */
150 if (b[bufl - 1] != '\n' && !php_stream_eof(stream)) {
151 if (buflen < (bufl + (b - buf) + EXEC_INPUT_BUF)) {
152 bufl += b - buf;
153 buflen = bufl + EXEC_INPUT_BUF;
154 buf = erealloc(buf, buflen);
155 b = buf + bufl;
156 } else {
157 b += bufl;
158 }
159 continue;
160 } else if (b != buf) {
161 bufl += b - buf;
162 }
163
164 bufl = handle_line(type, array, buf, bufl);
165 b = buf;
166 }
167 if (bufl) {
168 if (buf != b) {
169 /* Process remaining output */
170 bufl = handle_line(type, array, buf, bufl);
171 }
172
173 /* Return last line from the shell command */
174 bufl = strip_trailing_whitespace(buf, bufl);
175 RETVAL_STRINGL(buf, bufl);
176 } else { /* should return NULL, but for BC we return "" */
177 RETVAL_EMPTY_STRING();
178 }
179 } else {
180 ssize_t read;
181 while ((read = php_stream_read(stream, buf, EXEC_INPUT_BUF)) > 0) {
182 PHPWRITE(buf, read);
183 }
184 }
185
186 pclose_return = php_stream_close(stream);
187 efree(buf);
188
189 done:
190 #if PHP_SIGCHILD
191 if (sig_handler) {
192 signal(SIGCHLD, sig_handler);
193 }
194 #endif
195 if (d) {
196 efree(d);
197 }
198 return pclose_return;
199 err:
200 pclose_return = -1;
201 RETVAL_FALSE;
202 goto done;
203 }
204 /* }}} */
205
php_exec_ex(INTERNAL_FUNCTION_PARAMETERS,int mode)206 static void php_exec_ex(INTERNAL_FUNCTION_PARAMETERS, int mode) /* {{{ */
207 {
208 char *cmd;
209 size_t cmd_len;
210 zval *ret_code=NULL, *ret_array=NULL;
211 int ret;
212
213 ZEND_PARSE_PARAMETERS_START(1, (mode ? 2 : 3))
214 Z_PARAM_STRING(cmd, cmd_len)
215 Z_PARAM_OPTIONAL
216 if (!mode) {
217 Z_PARAM_ZVAL(ret_array)
218 }
219 Z_PARAM_ZVAL(ret_code)
220 ZEND_PARSE_PARAMETERS_END();
221
222 if (!cmd_len) {
223 zend_argument_value_error(1, "cannot be empty");
224 RETURN_THROWS();
225 }
226 if (strlen(cmd) != cmd_len) {
227 zend_argument_value_error(1, "must not contain any null bytes");
228 RETURN_THROWS();
229 }
230
231 if (!ret_array) {
232 ret = php_exec(mode, cmd, NULL, return_value);
233 } else {
234 if (Z_TYPE_P(Z_REFVAL_P(ret_array)) == IS_ARRAY) {
235 ZVAL_DEREF(ret_array);
236 SEPARATE_ARRAY(ret_array);
237 } else {
238 ret_array = zend_try_array_init(ret_array);
239 if (!ret_array) {
240 RETURN_THROWS();
241 }
242 }
243
244 ret = php_exec(2, cmd, ret_array, return_value);
245 }
246 if (ret_code) {
247 ZEND_TRY_ASSIGN_REF_LONG(ret_code, ret);
248 }
249 }
250 /* }}} */
251
252 /* {{{ Execute an external program */
PHP_FUNCTION(exec)253 PHP_FUNCTION(exec)
254 {
255 php_exec_ex(INTERNAL_FUNCTION_PARAM_PASSTHRU, 0);
256 }
257 /* }}} */
258
259 /* {{{ Execute an external program and display output */
PHP_FUNCTION(system)260 PHP_FUNCTION(system)
261 {
262 php_exec_ex(INTERNAL_FUNCTION_PARAM_PASSTHRU, 1);
263 }
264 /* }}} */
265
266 /* {{{ Execute an external program and display raw output */
PHP_FUNCTION(passthru)267 PHP_FUNCTION(passthru)
268 {
269 php_exec_ex(INTERNAL_FUNCTION_PARAM_PASSTHRU, 3);
270 }
271 /* }}} */
272
273 /* {{{ php_escape_shell_cmd
274 Escape all chars that could possibly be used to
275 break out of a shell command
276
277 This function emalloc's a string and returns the pointer.
278 Remember to efree it when done with it.
279
280 *NOT* safe for binary strings
281 */
php_escape_shell_cmd(const char * str)282 PHPAPI zend_string *php_escape_shell_cmd(const char *str)
283 {
284 size_t x, y;
285 size_t l = strlen(str);
286 uint64_t estimate = (2 * (uint64_t)l) + 1;
287 zend_string *cmd;
288 #ifndef PHP_WIN32
289 char *p = NULL;
290 #endif
291
292 /* max command line length - two single quotes - \0 byte length */
293 if (l > cmd_max_len - 2 - 1) {
294 php_error_docref(NULL, E_ERROR, "Command exceeds the allowed length of %zu bytes", cmd_max_len);
295 return ZSTR_EMPTY_ALLOC();
296 }
297
298 cmd = zend_string_safe_alloc(2, l, 0, 0);
299
300 for (x = 0, y = 0; x < l; x++) {
301 int mb_len = php_mblen(str + x, (l - x));
302
303 /* skip non-valid multibyte characters */
304 if (mb_len < 0) {
305 continue;
306 } else if (mb_len > 1) {
307 memcpy(ZSTR_VAL(cmd) + y, str + x, mb_len);
308 y += mb_len;
309 x += mb_len - 1;
310 continue;
311 }
312
313 switch (str[x]) {
314 #ifndef PHP_WIN32
315 case '"':
316 case '\'':
317 if (!p && (p = memchr(str + x + 1, str[x], l - x - 1))) {
318 /* noop */
319 } else if (p && *p == str[x]) {
320 p = NULL;
321 } else {
322 ZSTR_VAL(cmd)[y++] = '\\';
323 }
324 ZSTR_VAL(cmd)[y++] = str[x];
325 break;
326 #else
327 /* % is Windows specific for environmental variables, ^%PATH% will
328 output PATH while ^%PATH^% will not. escapeshellcmd->val will escape all % and !.
329 */
330 case '%':
331 case '!':
332 case '"':
333 case '\'':
334 #endif
335 case '#': /* This is character-set independent */
336 case '&':
337 case ';':
338 case '`':
339 case '|':
340 case '*':
341 case '?':
342 case '~':
343 case '<':
344 case '>':
345 case '^':
346 case '(':
347 case ')':
348 case '[':
349 case ']':
350 case '{':
351 case '}':
352 case '$':
353 case '\\':
354 case '\x0A': /* excluding these two */
355 case '\xFF':
356 #ifdef PHP_WIN32
357 ZSTR_VAL(cmd)[y++] = '^';
358 #else
359 ZSTR_VAL(cmd)[y++] = '\\';
360 #endif
361 ZEND_FALLTHROUGH;
362 default:
363 ZSTR_VAL(cmd)[y++] = str[x];
364
365 }
366 }
367 ZSTR_VAL(cmd)[y] = '\0';
368
369 if (y > cmd_max_len + 1) {
370 php_error_docref(NULL, E_ERROR, "Escaped command exceeds the allowed length of %zu bytes", cmd_max_len);
371 zend_string_release_ex(cmd, 0);
372 return ZSTR_EMPTY_ALLOC();
373 }
374
375 if ((estimate - y) > 4096) {
376 /* realloc if the estimate was way overill
377 * Arbitrary cutoff point of 4096 */
378 cmd = zend_string_truncate(cmd, y, 0);
379 }
380
381 ZSTR_LEN(cmd) = y;
382
383 return cmd;
384 }
385 /* }}} */
386
387 /* {{{ php_escape_shell_arg */
php_escape_shell_arg(const char * str)388 PHPAPI zend_string *php_escape_shell_arg(const char *str)
389 {
390 size_t x, y = 0;
391 size_t l = strlen(str);
392 zend_string *cmd;
393 uint64_t estimate = (4 * (uint64_t)l) + 3;
394
395 /* max command line length - two single quotes - \0 byte length */
396 if (l > cmd_max_len - 2 - 1) {
397 php_error_docref(NULL, E_ERROR, "Argument exceeds the allowed length of %zu bytes", cmd_max_len);
398 return ZSTR_EMPTY_ALLOC();
399 }
400
401 cmd = zend_string_safe_alloc(4, l, 2, 0); /* worst case */
402
403 #ifdef PHP_WIN32
404 ZSTR_VAL(cmd)[y++] = '"';
405 #else
406 ZSTR_VAL(cmd)[y++] = '\'';
407 #endif
408
409 for (x = 0; x < l; x++) {
410 int mb_len = php_mblen(str + x, (l - x));
411
412 /* skip non-valid multibyte characters */
413 if (mb_len < 0) {
414 continue;
415 } else if (mb_len > 1) {
416 memcpy(ZSTR_VAL(cmd) + y, str + x, mb_len);
417 y += mb_len;
418 x += mb_len - 1;
419 continue;
420 }
421
422 switch (str[x]) {
423 #ifdef PHP_WIN32
424 case '"':
425 case '%':
426 case '!':
427 ZSTR_VAL(cmd)[y++] = ' ';
428 break;
429 #else
430 case '\'':
431 ZSTR_VAL(cmd)[y++] = '\'';
432 ZSTR_VAL(cmd)[y++] = '\\';
433 ZSTR_VAL(cmd)[y++] = '\'';
434 #endif
435 ZEND_FALLTHROUGH;
436 default:
437 ZSTR_VAL(cmd)[y++] = str[x];
438 }
439 }
440 #ifdef PHP_WIN32
441 if (y > 0 && '\\' == ZSTR_VAL(cmd)[y - 1]) {
442 int k = 0, n = y - 1;
443 for (; n >= 0 && '\\' == ZSTR_VAL(cmd)[n]; n--, k++);
444 if (k % 2) {
445 ZSTR_VAL(cmd)[y++] = '\\';
446 }
447 }
448
449 ZSTR_VAL(cmd)[y++] = '"';
450 #else
451 ZSTR_VAL(cmd)[y++] = '\'';
452 #endif
453 ZSTR_VAL(cmd)[y] = '\0';
454
455 if (y > cmd_max_len + 1) {
456 php_error_docref(NULL, E_ERROR, "Escaped argument exceeds the allowed length of %zu bytes", cmd_max_len);
457 zend_string_release_ex(cmd, 0);
458 return ZSTR_EMPTY_ALLOC();
459 }
460
461 if ((estimate - y) > 4096) {
462 /* realloc if the estimate was way overill
463 * Arbitrary cutoff point of 4096 */
464 cmd = zend_string_truncate(cmd, y, 0);
465 }
466 ZSTR_LEN(cmd) = y;
467 return cmd;
468 }
469 /* }}} */
470
471 /* {{{ Escape shell metacharacters */
PHP_FUNCTION(escapeshellcmd)472 PHP_FUNCTION(escapeshellcmd)
473 {
474 char *command;
475 size_t command_len;
476
477 ZEND_PARSE_PARAMETERS_START(1, 1)
478 Z_PARAM_STRING(command, command_len)
479 ZEND_PARSE_PARAMETERS_END();
480
481 if (command_len) {
482 if (command_len != strlen(command)) {
483 zend_argument_value_error(1, "must not contain any null bytes");
484 RETURN_THROWS();
485 }
486 RETVAL_STR(php_escape_shell_cmd(command));
487 } else {
488 RETVAL_EMPTY_STRING();
489 }
490 }
491 /* }}} */
492
493 /* {{{ Quote and escape an argument for use in a shell command */
PHP_FUNCTION(escapeshellarg)494 PHP_FUNCTION(escapeshellarg)
495 {
496 char *argument;
497 size_t argument_len;
498
499 ZEND_PARSE_PARAMETERS_START(1, 1)
500 Z_PARAM_STRING(argument, argument_len)
501 ZEND_PARSE_PARAMETERS_END();
502
503 if (argument_len != strlen(argument)) {
504 zend_argument_value_error(1, "must not contain any null bytes");
505 RETURN_THROWS();
506 }
507
508 RETVAL_STR(php_escape_shell_arg(argument));
509 }
510 /* }}} */
511
512 /* {{{ Execute command via shell and return complete output as string */
PHP_FUNCTION(shell_exec)513 PHP_FUNCTION(shell_exec)
514 {
515 FILE *in;
516 char *command;
517 size_t command_len;
518 zend_string *ret;
519 php_stream *stream;
520
521 ZEND_PARSE_PARAMETERS_START(1, 1)
522 Z_PARAM_STRING(command, command_len)
523 ZEND_PARSE_PARAMETERS_END();
524
525 if (!command_len) {
526 zend_argument_value_error(1, "cannot be empty");
527 RETURN_THROWS();
528 }
529 if (strlen(command) != command_len) {
530 zend_argument_value_error(1, "must not contain any null bytes");
531 RETURN_THROWS();
532 }
533
534 #ifdef PHP_WIN32
535 if ((in=VCWD_POPEN(command, "rt"))==NULL) {
536 #else
537 if ((in=VCWD_POPEN(command, "r"))==NULL) {
538 #endif
539 php_error_docref(NULL, E_WARNING, "Unable to execute '%s'", command);
540 RETURN_FALSE;
541 }
542
543 stream = php_stream_fopen_from_pipe(in, "rb");
544 ret = php_stream_copy_to_mem(stream, PHP_STREAM_COPY_ALL, 0);
545 php_stream_close(stream);
546
547 if (ret && ZSTR_LEN(ret) > 0) {
548 RETVAL_STR(ret);
549 }
550 }
551 /* }}} */
552
553 #ifdef HAVE_NICE
554 /* {{{ Change the priority of the current process */
555 PHP_FUNCTION(proc_nice)
556 {
557 zend_long pri;
558
559 ZEND_PARSE_PARAMETERS_START(1, 1)
560 Z_PARAM_LONG(pri)
561 ZEND_PARSE_PARAMETERS_END();
562
563 errno = 0;
564 php_ignore_value(nice(pri));
565 if (errno) {
566 #ifdef PHP_WIN32
567 char *err = php_win_err();
568 php_error_docref(NULL, E_WARNING, "%s", err);
569 php_win_err_free(err);
570 #else
571 php_error_docref(NULL, E_WARNING, "Only a super user may attempt to increase the priority of a process");
572 #endif
573 RETURN_FALSE;
574 }
575
576 RETURN_TRUE;
577 }
578 /* }}} */
579 #endif
580
