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  1. This patch is based on http://kyberdigi.cz/projects/execdir/ but instead trying
  2. to sanitize the exec command string inside PHP this job is handled by bash and
  3. a special restricted PHP-mode which strips off all path informations.
  4.  
  5. This patch depends on:
  6. - bash restricted php mode patch
  7.   https://manuel.mausz.at/coding/patches/php/bash-4.2-restricted-php.patch
  8.  
  9. No warranty!
  10. --- a/ext/standard/exec.c	2025-11-04 17:38:06.000000000 +0100
  11. +++ b/ext/standard/exec.c	2025-11-14 15:36:33.038427564 +0100
  12. @@ -114,17 +114,28 @@
  13.  	FILE *fp;
  14.  	char *buf;
  15.  	int pclose_return;
  16. -	char *b, *d=NULL;
  17. +	char *cmd_p, *b, *d=NULL;
  18.  	php_stream *stream;
  19.  	size_t buflen, bufl = 0;
  20.  #if PHP_SIGCHILD
  21.  	void (*sig_handler)(int) = signal(SIGCHLD, SIG_DFL);
  22.  #endif
  23.  
  24. +	if (PG(exec_dir) && strlen(PG(exec_dir))) {
  25. +		zend_string *cmd_str = zend_string_init(cmd, strlen(cmd), 0);
  26. +		zend_string *cmd_esc = php_escape_shell_arg(cmd_str);
  27. +		spprintf(&d, 0, "PATH=%s /bin/bash --php -rc %s", PG(exec_dir), ZSTR_VAL(cmd_esc));
  28. +		zend_string_release(cmd_esc);
  29. +		zend_string_release(cmd_str);
  30. +		cmd_p = d;
  31. +	} else {
  32. +		cmd_p = cmd;
  33. +	}
  34. +
  35.  #ifdef PHP_WIN32
  36. -	fp = VCWD_POPEN(cmd, "rb");
  37. +	fp = VCWD_POPEN(cmd_p, "rb");
  38.  #else
  39. -	fp = VCWD_POPEN(cmd, "r");
  40. +	fp = VCWD_POPEN(cmd_p, "r");
  41.  #endif
  42.  	if (!fp) {
  43.  		php_error_docref(NULL, E_WARNING, "Unable to fork [%s]", cmd);
  44. @@ -498,7 +509,7 @@
  45.  PHP_FUNCTION(shell_exec)
  46.  {
  47.  	FILE *in;
  48. -	char *command;
  49. +	char *command, *command_p;
  50.  	size_t command_len;
  51.  	zend_string *ret;
  52.  	php_stream *stream;
  53. @@ -512,14 +523,26 @@
  54.  		RETURN_THROWS();
  55.  	}
  56.  
  57. +	if (PG(exec_dir) && strlen(PG(exec_dir))) {
  58. +		zend_string *cmd_str = zend_string_init(command, command_len, 0);
  59. +		zend_string *cmd_esc = php_escape_shell_arg(cmd_str);
  60. +		spprintf(&command_p, 0, "PATH=%s /bin/bash --php -rc %s", PG(exec_dir), ZSTR_VAL(cmd_esc));
  61. +		zend_string_release(cmd_esc);
  62. +		zend_string_release(cmd_str);
  63. +	} else {
  64. +		command_p = estrdup(command);
  65. +	}
  66. +
  67.  #ifdef PHP_WIN32
  68. -	if ((in=VCWD_POPEN(command, "rt"))==NULL) {
  69. +	if ((in=VCWD_POPEN(command_p, "rt"))==NULL) {
  70.  #else
  71. -	if ((in=VCWD_POPEN(command, "r"))==NULL) {
  72. +	if ((in=VCWD_POPEN(command_p, "r"))==NULL) {
  73.  #endif
  74.  		php_error_docref(NULL, E_WARNING, "Unable to execute '%s'", command);
  75. +		efree(command_p);
  76.  		RETURN_FALSE;
  77.  	}
  78. +	efree(command_p);
  79.  
  80.  	stream = php_stream_fopen_from_pipe(in, "rb");
  81.  	ret = php_stream_copy_to_mem(stream, PHP_STREAM_COPY_ALL, 0);
  82. --- a/ext/standard/file.c	2025-11-04 17:38:06.000000000 +0100
  83. +++ b/ext/standard/file.c	2025-11-14 15:36:33.039427557 +0100
  84. @@ -28,6 +28,7 @@
  85.  #include "ext/standard/basic_functions.h"
  86.  #include "php_ini.h"
  87.  #include "zend_smart_str.h"
  88. +#include "ext/standard/exec.h"
  89.  
  90.  #include <stdio.h>
  91.  #include <stdlib.h>
  92. @@ -805,7 +806,18 @@
  93.  		RETURN_THROWS();
  94.  	}
  95.  
  96. -	fp = VCWD_POPEN(command, posix_mode);
  97. +	if (PG(exec_dir) && strlen(PG(exec_dir))) {
  98. +		zend_string *cmd_str = zend_string_init(command, command_len, 0);
  99. +		zend_string *cmd_esc = php_escape_shell_arg(cmd_str);
  100. +		char *tmp;
  101. +		spprintf(&tmp, 0, "PATH=%s /bin/bash --php -rc %s", PG(exec_dir), ZSTR_VAL(cmd_esc));
  102. +		fp = VCWD_POPEN(tmp, posix_mode);
  103. +		efree(tmp);
  104. +		zend_string_release(cmd_esc);
  105. +		zend_string_release(cmd_str);
  106. +	} else {
  107. +		fp = VCWD_POPEN(command, posix_mode);
  108. +	}
  109.  	if (!fp) {
  110.  		php_error_docref2(NULL, command, posix_mode, E_WARNING, "%s", strerror(errno));
  111.  		efree(posix_mode);
  112. --- a/ext/standard/filestat.c	2025-11-04 17:38:06.000000000 +0100
  113. +++ b/ext/standard/filestat.c	2025-11-14 15:36:33.039427557 +0100
  114. @@ -746,6 +746,7 @@
  115.  	zend_stat_t *stat_sb = &ssb.sb;
  116.  	int flags = 0, rmask=S_IROTH, wmask=S_IWOTH, xmask=S_IXOTH; /* access rights defaults to other */
  117.  	const char *local = NULL;
  118. +	char local_safe[MAXPATHLEN];
  119.  	php_stream_wrapper *wrapper = NULL;
  120.  
  121.  	if (IS_ACCESS_CHECK(type)) {
  122. @@ -757,7 +758,7 @@
  123.  		}
  124.  
  125.  		if ((wrapper = php_stream_locate_url_wrapper(ZSTR_VAL(filename), &local, 0)) == &php_plain_files_wrapper
  126. -				&& php_check_open_basedir(local)) {
  127. +				&& type != FS_IS_X && php_check_open_basedir(local)) {
  128.  			RETURN_FALSE;
  129.  		}
  130.  
  131. @@ -787,9 +788,25 @@
  132.  					break;
  133.  #endif
  134.  #ifdef X_OK
  135. -				case FS_IS_X:
  136. -					RETURN_BOOL(VCWD_ACCESS(file_path_to_check, X_OK) == 0);
  137. +				case FS_IS_X: {
  138. +					bool xok = (VCWD_ACCESS(file_path_to_check, X_OK) == 0);
  139. +					if (!xok && PG(exec_dir) && strlen(PG(exec_dir))) {
  140. +						if (strstr(file_path_to_check, "..")) {
  141. +							RETURN_FALSE;
  142. +						} else {
  143. +							char *b = strrchr(file_path_to_check, PHP_DIR_SEPARATOR);
  144. +							if (b) {
  145. +								snprintf(local_safe, MAXPATHLEN, "%s%s", PG(exec_dir), b);
  146. +							} else {
  147. +								snprintf(local_safe, MAXPATHLEN, "%s%c%s", PG(exec_dir), PHP_DIR_SEPARATOR, file_path_to_check);
  148. +							}
  149. +							file_path_to_check = (char *)&local_safe;
  150. +						}
  151. +						xok = (VCWD_ACCESS(file_path_to_check, X_OK) == 0);
  152. +					}
  153. +					RETURN_BOOL(xok);
  154.  					break;
  155. +				}
  156.  #endif
  157.  			}
  158.  		}
  159. --- a/ext/standard/proc_open.c	2025-11-04 17:38:06.000000000 +0100
  160. +++ b/ext/standard/proc_open.c	2025-11-14 15:37:38.558984315 +0100
  161. @@ -780,7 +780,17 @@
  162.  	zend_string *command = NULL;
  163.  	uint32_t i = 0;
  164.  
  165. -	*argv = safe_emalloc(sizeof(char *), num_elems + 1, 0);
  166. +	*argv = safe_emalloc(sizeof(char *), num_elems + 1 + 5, 0);
  167. +
  168. +	if (PG(exec_dir) && strlen(PG(exec_dir))) {
  169. +		command = zend_string_init("/bin/bash", sizeof("/bin/bash") - 1, 0);
  170. +		(*argv)[i++] = estrdup("/bin/bash");
  171. +		(*argv)[i++] = estrdup("--php");
  172. +		(*argv)[i++] = estrdup("-rc");
  173. +		(*argv)[i++] = estrdup("exec \"$@\"");
  174. +		(*argv)[i++] = estrdup("bash");
  175. +		(*argv)[i] = NULL;
  176. +	}
  177.  
  178.  	ZEND_HASH_FOREACH_VAL(array, arg_zv) {
  179.  		zend_string *arg_str = get_valid_arg_string(arg_zv, i + 1);
  180. @@ -1278,8 +1288,37 @@
  181.  	}
  182.  #endif
  183.  
  184. +	HashTable *envpath = NULL;
  185. +	if (PG(exec_dir) && strlen(PG(exec_dir))) {
  186. +		zend_string *key;
  187. +		zend_ulong idx;
  188. +		zval *val;
  189. +		uint32_t count = environment ? zend_hash_num_elements(environment) : 0;
  190. +		ALLOC_HASHTABLE(envpath);
  191. +		zend_hash_init(envpath, count + 1, NULL, ZVAL_PTR_DTOR, 0);
  192. +		if (count) {
  193. +			ZEND_HASH_FOREACH_KEY_VAL(environment, idx, key, val) {
  194. +				if (key) {
  195. +					zend_hash_add_new(envpath, key, val);
  196. +				} else {
  197. +					zend_hash_index_add_new(envpath, idx, val);
  198. +				}
  199. +				zval_add_ref(val);
  200. +			} ZEND_HASH_FOREACH_END();
  201. +		}
  202. +		zval tmp;
  203. +		ZVAL_STRING(&tmp, PG(exec_dir));
  204. +		zend_hash_str_update(envpath, "PATH", strlen("PATH"), &tmp);
  205. +		environment = envpath;
  206. +	}
  207. +
  208.  	if (environment) {
  209.  		env = php_array_to_envp(environment);
  210. +		if (envpath) {
  211. +			zend_hash_destroy(envpath);
  212. +			FREE_HASHTABLE(envpath);
  213. +			environment = NULL;
  214. +		}
  215.  	}
  216.  
  217.  	descriptors = alloc_descriptor_array(descriptorspec);
  218. @@ -1403,9 +1442,15 @@
  219.  	if (argv) {
  220.  		r = posix_spawnp(&child, ZSTR_VAL(command_str), &factions, NULL, argv, (env.envarray ? env.envarray : environ));
  221.  	} else {
  222. -		r = posix_spawn(&child, "/bin/sh" , &factions, NULL,
  223. -				(char * const[]) {"sh", "-c", ZSTR_VAL(command_str), NULL},
  224. -				env.envarray ? env.envarray : environ);
  225. +		if (PG(exec_dir) && strlen(PG(exec_dir))) {
  226. +			r = posix_spawn(&child, "/bin/bash" , &factions, NULL,
  227. +					(char * const[]) {"bash", "--php", "-rc", ZSTR_VAL(command_str), NULL},
  228. +					env.envarray ? env.envarray : environ);
  229. +		} else {
  230. +			r = posix_spawn(&child, "/bin/sh" , &factions, NULL,
  231. +					(char * const[]) {"sh", "-c", ZSTR_VAL(command_str), NULL},
  232. +					env.envarray ? env.envarray : environ);
  233. +		}
  234.  	}
  235.  	posix_spawn_file_actions_destroy(&factions);
  236.  	if (r != 0) {
  237. @@ -1438,10 +1483,14 @@
  238.  			}
  239.  			execvp(ZSTR_VAL(command_str), argv);
  240.  		} else {
  241. -			if (env.envarray) {
  242. -				execle("/bin/sh", "sh", "-c", ZSTR_VAL(command_str), NULL, env.envarray);
  243. +			if (PG(exec_dir) && strlen(PG(exec_dir))) {
  244. +				execle("/bin/bash", "bash", "--php", "-rc", ZSTR_VAL(command_str), NULL, env.envarray);
  245.  			} else {
  246. -				execl("/bin/sh", "sh", "-c", ZSTR_VAL(command_str), NULL);
  247. +				if (env.envarray) {
  248. +					execle("/bin/sh", "sh", "-c", ZSTR_VAL(command_str), NULL, env.envarray);
  249. +				} else {
  250. +					execl("/bin/sh", "sh", "-c", ZSTR_VAL(command_str), NULL);
  251. +				}
  252.  			}
  253.  		}
  254.  
  255. --- a/main/main.c	2025-11-14 15:36:07.023603557 +0100
  256. +++ b/main/main.c	2025-11-14 15:36:33.040427551 +0100
  257. @@ -889,6 +889,7 @@
  258.  	STD_PHP_INI_ENTRY("syslog.facility",		"LOG_USER",		PHP_INI_SYSTEM,		OnSetFacility,		syslog_facility,	php_core_globals,		core_globals)
  259.  	STD_PHP_INI_ENTRY("syslog.ident",		"php",			PHP_INI_SYSTEM,		OnUpdateString,		syslog_ident,		php_core_globals,		core_globals)
  260.  	STD_PHP_INI_ENTRY("syslog.filter",		"no-ctrl",		PHP_INI_ALL,		OnSetLogFilter,		syslog_filter,		php_core_globals, 		core_globals)
  261. +	STD_PHP_INI_ENTRY("exec_dir",			NULL,		PHP_INI_SYSTEM,		OnUpdateString,		exec_dir,		php_core_globals,		core_globals)
  262.  PHP_INI_END()
  263.  /* }}} */
  264.  
  265. --- a/main/php_globals.h	2025-11-04 17:38:06.000000000 +0100
  266. +++ b/main/php_globals.h	2025-11-14 15:36:33.040427551 +0100
  267. @@ -173,6 +173,8 @@
  268.  	char *syslog_ident;
  269.  	zend_long syslog_filter;
  270.  	zend_long error_log_mode;
  271. +
  272. +	char *exec_dir;
  273.  };
  274.  
  275.  
  276. --- a/php.ini-development	2025-11-04 17:38:06.000000000 +0100
  277. +++ b/php.ini-development	2025-11-14 15:36:33.041427544 +0100
  278. @@ -317,6 +317,10 @@
  279.  ; https://php.net/open-basedir
  280.  ;open_basedir =
  281.  
  282. +; Only executables located in the exec_dir will be allowed to be executed
  283. +; via the exec family of functions.
  284. +exec_dir =
  285. +
  286.  ; This directive allows you to disable certain functions.
  287.  ; It receives a comma-delimited list of function names.
  288.  ; https://php.net/disable-functions
  289. --- a/php.ini-production	2025-11-04 17:38:06.000000000 +0100
  290. +++ b/php.ini-production	2025-11-14 15:36:33.041427544 +0100
  291. @@ -317,6 +317,10 @@
  292.  ; https://php.net/open-basedir
  293.  ;open_basedir =
  294.  
  295. +; Only executables located in the exec_dir will be allowed to be executed
  296. +; via the exec family of functions.
  297. +exec_dir =
  298. +
  299.  ; This directive allows you to disable certain functions.
  300.  ; It receives a comma-delimited list of function names.
  301.  ; https://php.net/disable-functions
  302.