1 /*
2 +----------------------------------------------------------------------+
3 | PHP Version 7 |
4 +----------------------------------------------------------------------+
5 | Copyright (c) 1997-2018 The PHP Group |
6 +----------------------------------------------------------------------+
7 | This source file is subject to version 3.01 of the PHP license, |
8 | that is bundled with this package in the file LICENSE, and is |
9 | available through the world-wide-web at the following url: |
10 | http://www.php.net/license/3_01.txt |
11 | If you did not receive a copy of the PHP license and are unable to |
12 | obtain it through the world-wide-web, please send a note to |
13 | license@php.net so we can mail you a copy immediately. |
14 +----------------------------------------------------------------------+
15 | Author: Rasmus Lerdorf <rasmus@php.net> |
16 | Ilia Alshanetsky <iliaa@php.net> |
17 +----------------------------------------------------------------------+
18 */
19 /* $Id$ */
20
21 #include <stdio.h>
22 #include "php.h"
23 #include <ctype.h>
24 #include "php_string.h"
25 #include "ext/standard/head.h"
26 #include "ext/standard/file.h"
27 #include "basic_functions.h"
28 #include "exec.h"
29 #include "php_globals.h"
30 #include "SAPI.h"
31
32 #if HAVE_SYS_WAIT_H
33 #include <sys/wait.h>
34 #endif
35 #if HAVE_SIGNAL_H
36 #include <signal.h>
37 #endif
38
39 #if HAVE_SYS_TYPES_H
40 #include <sys/types.h>
41 #endif
42 #if HAVE_SYS_STAT_H
43 #include <sys/stat.h>
44 #endif
45 #if HAVE_FCNTL_H
46 #include <fcntl.h>
47 #endif
48
49 #if HAVE_UNISTD_H
50 #include <unistd.h>
51 #endif
52
53 #if HAVE_LIMITS_H
54 #include <limits.h>
55 #endif
56
57 static size_t cmd_max_len;
58
59 /* {{{ PHP_MINIT_FUNCTION(exec) */
PHP_MINIT_FUNCTION(exec)60 PHP_MINIT_FUNCTION(exec)
61 {
62 #ifdef _SC_ARG_MAX
63 cmd_max_len = sysconf(_SC_ARG_MAX);
64 if ((size_t)-1 == cmd_max_len) {
65 #ifdef _POSIX_ARG_MAX
66 cmd_max_len = _POSIX_ARG_MAX;
67 #else
68 cmd_max_len = 4096;
69 #endif
70 }
71 #elif defined(ARG_MAX)
72 cmd_max_len = ARG_MAX;
73 #elif defined(PHP_WIN32)
74 /* Executed commands will run through cmd.exe. As long as it's the case,
75 it's just the constant limit.*/
76 cmd_max_len = 8192;
77 #else
78 /* This is just an arbitrary value for the fallback case. */
79 cmd_max_len = 4096;
80 #endif
81
82 return SUCCESS;
83 }
84 /* }}} */
85
86 /* {{{ php_exec
87 * If type==0, only last line of output is returned (exec)
88 * If type==1, all lines will be printed and last lined returned (system)
89 * If type==2, all lines will be saved to given array (exec with &$array)
90 * If type==3, output will be printed binary, no lines will be saved or returned (passthru)
91 *
92 */
php_exec(int type,char * cmd,zval * array,zval * return_value)93 PHPAPI int php_exec(int type, char *cmd, zval *array, zval *return_value)
94 {
95 FILE *fp;
96 char *buf;
97 size_t l = 0;
98 int pclose_return;
99 char *b, *d=NULL;
100 php_stream *stream;
101 size_t buflen, bufl = 0;
102 #if PHP_SIGCHILD
103 void (*sig_handler)() = NULL;
104 #endif
105
106 #if PHP_SIGCHILD
107 sig_handler = signal (SIGCHLD, SIG_DFL);
108 #endif
109
110 #ifdef PHP_WIN32
111 fp = VCWD_POPEN(cmd, "rb");
112 #else
113 fp = VCWD_POPEN(cmd, "r");
114 #endif
115 if (!fp) {
116 php_error_docref(NULL, E_WARNING, "Unable to fork [%s]", cmd);
117 goto err;
118 }
119
120 stream = php_stream_fopen_from_pipe(fp, "rb");
121
122 buf = (char *) emalloc(EXEC_INPUT_BUF);
123 buflen = EXEC_INPUT_BUF;
124
125 if (type != 3) {
126 b = buf;
127
128 while (php_stream_get_line(stream, b, EXEC_INPUT_BUF, &bufl)) {
129 /* no new line found, let's read some more */
130 if (b[bufl - 1] != '\n' && !php_stream_eof(stream)) {
131 if (buflen < (bufl + (b - buf) + EXEC_INPUT_BUF)) {
132 bufl += b - buf;
133 buflen = bufl + EXEC_INPUT_BUF;
134 buf = erealloc(buf, buflen);
135 b = buf + bufl;
136 } else {
137 b += bufl;
138 }
139 continue;
140 } else if (b != buf) {
141 bufl += b - buf;
142 }
143
144 if (type == 1) {
145 PHPWRITE(buf, bufl);
146 if (php_output_get_level() < 1) {
147 sapi_flush();
148 }
149 } else if (type == 2) {
150 /* strip trailing whitespaces */
151 l = bufl;
152 while (l-- > 0 && isspace(((unsigned char *)buf)[l]));
153 if (l != (bufl - 1)) {
154 bufl = l + 1;
155 buf[bufl] = '\0';
156 }
157 add_next_index_stringl(array, buf, bufl);
158 }
159 b = buf;
160 }
161 if (bufl) {
162 /* strip trailing whitespaces if we have not done so already */
163 if ((type == 2 && buf != b) || type != 2) {
164 l = bufl;
165 while (l-- > 0 && isspace(((unsigned char *)buf)[l]));
166 if (l != (bufl - 1)) {
167 bufl = l + 1;
168 buf[bufl] = '\0';
169 }
170 if (type == 2) {
171 add_next_index_stringl(array, buf, bufl);
172 }
173 }
174
175 /* Return last line from the shell command */
176 RETVAL_STRINGL(buf, bufl);
177 } else { /* should return NULL, but for BC we return "" */
178 RETVAL_EMPTY_STRING();
179 }
180 } else {
181 while((bufl = php_stream_read(stream, buf, EXEC_INPUT_BUF)) > 0) {
182 PHPWRITE(buf, bufl);
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 goto done;
202 }
203 /* }}} */
204
php_exec_ex(INTERNAL_FUNCTION_PARAMETERS,int mode)205 static void php_exec_ex(INTERNAL_FUNCTION_PARAMETERS, int mode) /* {{{ */
206 {
207 char *cmd;
208 size_t cmd_len;
209 zval *ret_code=NULL, *ret_array=NULL;
210 int ret;
211
212 if (mode) {
213 if (zend_parse_parameters(ZEND_NUM_ARGS(), "s|z/", &cmd, &cmd_len, &ret_code) == FAILURE) {
214 RETURN_FALSE;
215 }
216 } else {
217 if (zend_parse_parameters(ZEND_NUM_ARGS(), "s|z/z/", &cmd, &cmd_len, &ret_array, &ret_code) == FAILURE) {
218 RETURN_FALSE;
219 }
220 }
221 if (!cmd_len) {
222 php_error_docref(NULL, E_WARNING, "Cannot execute a blank command");
223 RETURN_FALSE;
224 }
225 if (strlen(cmd) != cmd_len) {
226 php_error_docref(NULL, E_WARNING, "NULL byte detected. Possible attack");
227 RETURN_FALSE;
228 }
229
230 if (!ret_array) {
231 ret = php_exec(mode, cmd, NULL, return_value);
232 } else {
233 if (Z_TYPE_P(ret_array) != IS_ARRAY) {
234 zval_dtor(ret_array);
235 array_init(ret_array);
236 }
237 ret = php_exec(2, cmd, ret_array, return_value);
238 }
239 if (ret_code) {
240 zval_dtor(ret_code);
241 ZVAL_LONG(ret_code, ret);
242 }
243 }
244 /* }}} */
245
246 /* {{{ proto string exec(string command [, array &output [, int &return_value]])
247 Execute an external program */
PHP_FUNCTION(exec)248 PHP_FUNCTION(exec)
249 {
250 php_exec_ex(INTERNAL_FUNCTION_PARAM_PASSTHRU, 0);
251 }
252 /* }}} */
253
254 /* {{{ proto int system(string command [, int &return_value])
255 Execute an external program and display output */
PHP_FUNCTION(system)256 PHP_FUNCTION(system)
257 {
258 php_exec_ex(INTERNAL_FUNCTION_PARAM_PASSTHRU, 1);
259 }
260 /* }}} */
261
262 /* {{{ proto void passthru(string command [, int &return_value])
263 Execute an external program and display raw output */
PHP_FUNCTION(passthru)264 PHP_FUNCTION(passthru)
265 {
266 php_exec_ex(INTERNAL_FUNCTION_PARAM_PASSTHRU, 3);
267 }
268 /* }}} */
269
270 /* {{{ php_escape_shell_cmd
271 Escape all chars that could possibly be used to
272 break out of a shell command
273
274 This function emalloc's a string and returns the pointer.
275 Remember to efree it when done with it.
276
277 *NOT* safe for binary strings
278 */
php_escape_shell_cmd(char * str)279 PHPAPI zend_string *php_escape_shell_cmd(char *str)
280 {
281 register size_t x, y;
282 size_t l = strlen(str);
283 uint64_t estimate = (2 * (uint64_t)l) + 1;
284 zend_string *cmd;
285 #ifndef PHP_WIN32
286 char *p = NULL;
287 #endif
288
289 /* max command line length - two single quotes - \0 byte length */
290 if (l > cmd_max_len - 2 - 1) {
291 php_error_docref(NULL, E_ERROR, "Command exceeds the allowed length of %d bytes", cmd_max_len);
292 return ZSTR_EMPTY_ALLOC();
293 }
294
295 cmd = zend_string_safe_alloc(2, l, 0, 0);
296
297 for (x = 0, y = 0; x < l; x++) {
298 int mb_len = php_mblen(str + x, (l - x));
299
300 /* skip non-valid multibyte characters */
301 if (mb_len < 0) {
302 continue;
303 } else if (mb_len > 1) {
304 memcpy(ZSTR_VAL(cmd) + y, str + x, mb_len);
305 y += mb_len;
306 x += mb_len - 1;
307 continue;
308 }
309
310 switch (str[x]) {
311 #ifndef PHP_WIN32
312 case '"':
313 case '\'':
314 if (!p && (p = memchr(str + x + 1, str[x], l - x - 1))) {
315 /* noop */
316 } else if (p && *p == str[x]) {
317 p = NULL;
318 } else {
319 ZSTR_VAL(cmd)[y++] = '\\';
320 }
321 ZSTR_VAL(cmd)[y++] = str[x];
322 break;
323 #else
324 /* % is Windows specific for environmental variables, ^%PATH% will
325 output PATH while ^%PATH^% will not. escapeshellcmd->val will escape all % and !.
326 */
327 case '%':
328 case '!':
329 case '"':
330 case '\'':
331 #endif
332 case '#': /* This is character-set independent */
333 case '&':
334 case ';':
335 case '`':
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 '\x0A': /* excluding these two */
352 case '\xFF':
353 #ifdef PHP_WIN32
354 ZSTR_VAL(cmd)[y++] = '^';
355 #else
356 ZSTR_VAL(cmd)[y++] = '\\';
357 #endif
358 /* fall-through */
359 default:
360 ZSTR_VAL(cmd)[y++] = str[x];
361
362 }
363 }
364 ZSTR_VAL(cmd)[y] = '\0';
365
366 if (y > cmd_max_len + 1) {
367 php_error_docref(NULL, E_ERROR, "Escaped command exceeds the allowed length of %d bytes", cmd_max_len);
368 zend_string_release(cmd);
369 return ZSTR_EMPTY_ALLOC();
370 }
371
372 if ((estimate - y) > 4096) {
373 /* realloc if the estimate was way overill
374 * Arbitrary cutoff point of 4096 */
375 cmd = zend_string_truncate(cmd, y, 0);
376 }
377
378 ZSTR_LEN(cmd) = y;
379
380 return cmd;
381 }
382 /* }}} */
383
384 /* {{{ php_escape_shell_arg
385 */
php_escape_shell_arg(char * str)386 PHPAPI zend_string *php_escape_shell_arg(char *str)
387 {
388 size_t x, y = 0;
389 size_t l = strlen(str);
390 zend_string *cmd;
391 uint64_t estimate = (4 * (uint64_t)l) + 3;
392
393 /* max command line length - two single quotes - \0 byte length */
394 if (l > cmd_max_len - 2 - 1) {
395 php_error_docref(NULL, E_ERROR, "Argument exceeds the allowed length of %d bytes", cmd_max_len);
396 return ZSTR_EMPTY_ALLOC();
397 }
398
399 cmd = zend_string_safe_alloc(4, l, 2, 0); /* worst case */
400
401 #ifdef PHP_WIN32
402 ZSTR_VAL(cmd)[y++] = '"';
403 #else
404 ZSTR_VAL(cmd)[y++] = '\'';
405 #endif
406
407 for (x = 0; x < l; x++) {
408 int mb_len = php_mblen(str + x, (l - x));
409
410 /* skip non-valid multibyte characters */
411 if (mb_len < 0) {
412 continue;
413 } else if (mb_len > 1) {
414 memcpy(ZSTR_VAL(cmd) + y, str + x, mb_len);
415 y += mb_len;
416 x += mb_len - 1;
417 continue;
418 }
419
420 switch (str[x]) {
421 #ifdef PHP_WIN32
422 case '"':
423 case '%':
424 case '!':
425 ZSTR_VAL(cmd)[y++] = ' ';
426 break;
427 #else
428 case '\'':
429 ZSTR_VAL(cmd)[y++] = '\'';
430 ZSTR_VAL(cmd)[y++] = '\\';
431 ZSTR_VAL(cmd)[y++] = '\'';
432 #endif
433 /* fall-through */
434 default:
435 ZSTR_VAL(cmd)[y++] = str[x];
436 }
437 }
438 #ifdef PHP_WIN32
439 if (y > 0 && '\\' == ZSTR_VAL(cmd)[y - 1]) {
440 int k = 0, n = y - 1;
441 for (; n >= 0 && '\\' == ZSTR_VAL(cmd)[n]; n--, k++);
442 if (k % 2) {
443 ZSTR_VAL(cmd)[y++] = '\\';
444 }
445 }
446
447 ZSTR_VAL(cmd)[y++] = '"';
448 #else
449 ZSTR_VAL(cmd)[y++] = '\'';
450 #endif
451 ZSTR_VAL(cmd)[y] = '\0';
452
453 if (y > cmd_max_len + 1) {
454 php_error_docref(NULL, E_ERROR, "Escaped argument exceeds the allowed length of %d bytes", cmd_max_len);
455 zend_string_release(cmd);
456 return ZSTR_EMPTY_ALLOC();
457 }
458
459 if ((estimate - y) > 4096) {
460 /* realloc if the estimate was way overill
461 * Arbitrary cutoff point of 4096 */
462 cmd = zend_string_truncate(cmd, y, 0);
463 }
464 ZSTR_LEN(cmd) = y;
465 return cmd;
466 }
467 /* }}} */
468
469 /* {{{ proto string escapeshellcmd(string command)
470 Escape shell metacharacters */
PHP_FUNCTION(escapeshellcmd)471 PHP_FUNCTION(escapeshellcmd)
472 {
473 char *command;
474 size_t command_len;
475
476 if (zend_parse_parameters(ZEND_NUM_ARGS(), "s", &command, &command_len) == FAILURE) {
477 return;
478 }
479
480 if (command_len) {
481 if (command_len != strlen(command)) {
482 php_error_docref(NULL, E_ERROR, "Input string contains NULL bytes");
483 return;
484 }
485 RETVAL_STR(php_escape_shell_cmd(command));
486 } else {
487 RETVAL_EMPTY_STRING();
488 }
489 }
490 /* }}} */
491
492 /* {{{ proto string escapeshellarg(string arg)
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 if (zend_parse_parameters(ZEND_NUM_ARGS(), "s", &argument, &argument_len) == FAILURE) {
500 return;
501 }
502
503 if (argument) {
504 if (argument_len != strlen(argument)) {
505 php_error_docref(NULL, E_ERROR, "Input string contains NULL bytes");
506 return;
507 }
508 RETVAL_STR(php_escape_shell_arg(argument));
509 }
510 }
511 /* }}} */
512
513 /* {{{ proto string shell_exec(string cmd)
514 Execute command via shell and return complete output as string */
PHP_FUNCTION(shell_exec)515 PHP_FUNCTION(shell_exec)
516 {
517 FILE *in;
518 char *command;
519 size_t command_len;
520 zend_string *ret;
521 php_stream *stream;
522
523 if (zend_parse_parameters(ZEND_NUM_ARGS(), "s", &command, &command_len) == FAILURE) {
524 return;
525 }
526
527 #ifdef PHP_WIN32
528 if ((in=VCWD_POPEN(command, "rt"))==NULL) {
529 #else
530 if ((in=VCWD_POPEN(command, "r"))==NULL) {
531 #endif
532 php_error_docref(NULL, E_WARNING, "Unable to execute '%s'", command);
533 RETURN_FALSE;
534 }
535
536 stream = php_stream_fopen_from_pipe(in, "rb");
537 ret = php_stream_copy_to_mem(stream, PHP_STREAM_COPY_ALL, 0);
538 php_stream_close(stream);
539
540 if (ret && ZSTR_LEN(ret) > 0) {
541 RETVAL_STR(ret);
542 }
543 }
544 /* }}} */
545
546 #ifdef HAVE_NICE
547 /* {{{ proto bool proc_nice(int priority)
548 Change the priority of the current process */
549 PHP_FUNCTION(proc_nice)
550 {
551 zend_long pri;
552
553 if (zend_parse_parameters(ZEND_NUM_ARGS(), "l", &pri) == FAILURE) {
554 RETURN_FALSE;
555 }
556
557 errno = 0;
558 php_ignore_value(nice(pri));
559 if (errno) {
560 php_error_docref(NULL, E_WARNING, "Only a super user may attempt to increase the priority of a process");
561 RETURN_FALSE;
562 }
563
564 RETURN_TRUE;
565 }
566 /* }}} */
567 #endif
568
569 /*
570 * Local variables:
571 * tab-width: 4
572 * c-basic-offset: 4
573 * End:
574 * vim600: sw=4 ts=4 fdm=marker
575 * vim<600: sw=4 ts=4
576 */
577
