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