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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. diff -Naur a/ext/standard/exec.c b/ext/standard/exec.c
  11. --- a/ext/standard/exec.c	2025-09-09 13:09:59.000000000 +0200
  12. +++ b/ext/standard/exec.c	2025-09-16 21:32:25.596400863 +0200
  13. @@ -114,17 +114,28 @@
  14.  	FILE *fp;
  15.  	char *buf;
  16.  	int pclose_return;
  17. -	char *b, *d=NULL;
  18. +	char *cmd_p, *b, *d=NULL;
  19.  	php_stream *stream;
  20.  	size_t buflen, bufl = 0;
  21.  #if PHP_SIGCHILD
  22.  	void (*sig_handler)(int) = signal(SIGCHLD, SIG_DFL);
  23.  #endif
  24.  
  25. +	if (PG(exec_dir) && strlen(PG(exec_dir))) {
  26. +		zend_string *cmd_str = zend_string_init(cmd, strlen(cmd), 0);
  27. +		zend_string *cmd_esc = php_escape_shell_arg(cmd_str);
  28. +		spprintf(&d, 0, "PATH=%s /bin/bash --php -rc %s", PG(exec_dir), ZSTR_VAL(cmd_esc));
  29. +		zend_string_release(cmd_esc);
  30. +		zend_string_release(cmd_str);
  31. +		cmd_p = d;
  32. +	} else {
  33. +		cmd_p = cmd;
  34. +	}
  35. +
  36.  #ifdef PHP_WIN32
  37. -	fp = VCWD_POPEN(cmd, "rb");
  38. +	fp = VCWD_POPEN(cmd_p, "rb");
  39.  #else
  40. -	fp = VCWD_POPEN(cmd, "r");
  41. +	fp = VCWD_POPEN(cmd_p, "r");
  42.  #endif
  43.  	if (!fp) {
  44.  		php_error_docref(NULL, E_WARNING, "Unable to fork [%s]", cmd);
  45. @@ -498,7 +509,7 @@
  46.  PHP_FUNCTION(shell_exec)
  47.  {
  48.  	FILE *in;
  49. -	char *command;
  50. +	char *command, *command_p;
  51.  	size_t command_len;
  52.  	zend_string *ret;
  53.  	php_stream *stream;
  54. @@ -512,14 +523,26 @@
  55.  		RETURN_THROWS();
  56.  	}
  57.  
  58. +	if (PG(exec_dir) && strlen(PG(exec_dir))) {
  59. +		zend_string *cmd_str = zend_string_init(command, command_len, 0);
  60. +		zend_string *cmd_esc = php_escape_shell_arg(cmd_str);
  61. +		spprintf(&command_p, 0, "PATH=%s /bin/bash --php -rc %s", PG(exec_dir), ZSTR_VAL(cmd_esc));
  62. +		zend_string_release(cmd_esc);
  63. +		zend_string_release(cmd_str);
  64. +	} else {
  65. +		command_p = estrdup(command);
  66. +	}
  67. +
  68.  #ifdef PHP_WIN32
  69. -	if ((in=VCWD_POPEN(command, "rt"))==NULL) {
  70. +	if ((in=VCWD_POPEN(command_p, "rt"))==NULL) {
  71.  #else
  72. -	if ((in=VCWD_POPEN(command, "r"))==NULL) {
  73. +	if ((in=VCWD_POPEN(command_p, "r"))==NULL) {
  74.  #endif
  75.  		php_error_docref(NULL, E_WARNING, "Unable to execute '%s'", command);
  76. +		efree(command_p);
  77.  		RETURN_FALSE;
  78.  	}
  79. +	efree(command_p);
  80.  
  81.  	stream = php_stream_fopen_from_pipe(in, "rb");
  82.  	ret = php_stream_copy_to_mem(stream, PHP_STREAM_COPY_ALL, 0);
  83. diff -Naur a/ext/standard/file.c b/ext/standard/file.c
  84. --- a/ext/standard/file.c	2025-09-09 13:09:59.000000000 +0200
  85. +++ b/ext/standard/file.c	2025-09-16 21:32:25.597400856 +0200
  86. @@ -28,6 +28,7 @@
  87.  #include "ext/standard/basic_functions.h"
  88.  #include "php_ini.h"
  89.  #include "zend_smart_str.h"
  90. +#include "ext/standard/exec.h"
  91.  
  92.  #include <stdio.h>
  93.  #include <stdlib.h>
  94. @@ -805,7 +806,18 @@
  95.  		RETURN_THROWS();
  96.  	}
  97.  
  98. -	fp = VCWD_POPEN(command, posix_mode);
  99. +	if (PG(exec_dir) && strlen(PG(exec_dir))) {
  100. +		zend_string *cmd_str = zend_string_init(command, command_len, 0);
  101. +		zend_string *cmd_esc = php_escape_shell_arg(cmd_str);
  102. +		char *tmp;
  103. +		spprintf(&tmp, 0, "PATH=%s /bin/bash --php -rc %s", PG(exec_dir), ZSTR_VAL(cmd_esc));
  104. +		fp = VCWD_POPEN(tmp, posix_mode);
  105. +		efree(tmp);
  106. +		zend_string_release(cmd_esc);
  107. +		zend_string_release(cmd_str);
  108. +	} else {
  109. +		fp = VCWD_POPEN(command, posix_mode);
  110. +	}
  111.  	if (!fp) {
  112.  		php_error_docref2(NULL, command, posix_mode, E_WARNING, "%s", strerror(errno));
  113.  		efree(posix_mode);
  114. diff -Naur a/ext/standard/filestat.c b/ext/standard/filestat.c
  115. --- a/ext/standard/filestat.c	2025-09-09 13:09:59.000000000 +0200
  116. +++ b/ext/standard/filestat.c	2025-09-16 21:32:25.597400856 +0200
  117. @@ -746,6 +746,7 @@
  118.  	zend_stat_t *stat_sb = &ssb.sb;
  119.  	int flags = 0, rmask=S_IROTH, wmask=S_IWOTH, xmask=S_IXOTH; /* access rights defaults to other */
  120.  	const char *local = NULL;
  121. +	char local_safe[MAXPATHLEN];
  122.  	php_stream_wrapper *wrapper = NULL;
  123.  
  124.  	if (IS_ACCESS_CHECK(type)) {
  125. @@ -757,7 +758,7 @@
  126.  		}
  127.  
  128.  		if ((wrapper = php_stream_locate_url_wrapper(ZSTR_VAL(filename), &local, 0)) == &php_plain_files_wrapper
  129. -				&& php_check_open_basedir(local)) {
  130. +				&& type != FS_IS_X && php_check_open_basedir(local)) {
  131.  			RETURN_FALSE;
  132.  		}
  133.  
  134. @@ -787,9 +788,25 @@
  135.  					break;
  136.  #endif
  137.  #ifdef X_OK
  138. -				case FS_IS_X:
  139. -					RETURN_BOOL(VCWD_ACCESS(file_path_to_check, X_OK) == 0);
  140. +				case FS_IS_X: {
  141. +					bool xok = (VCWD_ACCESS(file_path_to_check, X_OK) == 0);
  142. +					if (!xok && PG(exec_dir) && strlen(PG(exec_dir))) {
  143. +						if (strstr(file_path_to_check, "..")) {
  144. +							RETURN_FALSE;
  145. +						} else {
  146. +							char *b = strrchr(file_path_to_check, PHP_DIR_SEPARATOR);
  147. +							if (b) {
  148. +								snprintf(local_safe, MAXPATHLEN, "%s%s", PG(exec_dir), b);
  149. +							} else {
  150. +								snprintf(local_safe, MAXPATHLEN, "%s%c%s", PG(exec_dir), PHP_DIR_SEPARATOR, file_path_to_check);
  151. +							}
  152. +							file_path_to_check = (char *)&local_safe;
  153. +						}
  154. +						xok = (VCWD_ACCESS(file_path_to_check, X_OK) == 0);
  155. +					}
  156. +					RETURN_BOOL(xok);
  157.  					break;
  158. +				}
  159.  #endif
  160.  			}
  161.  		}
  162. diff -Naur a/ext/standard/proc_open.c b/ext/standard/proc_open.c
  163. --- a/ext/standard/proc_open.c	2025-09-09 13:09:59.000000000 +0200
  164. +++ b/ext/standard/proc_open.c	2025-09-16 21:32:25.597400856 +0200
  165. @@ -780,7 +780,17 @@
  166.  	zend_string *command = NULL;
  167.  	uint32_t i = 0;
  168.  
  169. -	*argv = safe_emalloc(sizeof(char *), num_elems + 1, 0);
  170. +	*argv = safe_emalloc(sizeof(char *), num_elems + 1 + 5, 0);
  171. +
  172. +	if (PG(exec_dir) && strlen(PG(exec_dir))) {
  173. +		command = zend_string_init("/bin/bash", sizeof("/bin/bash") - 1, 0);
  174. +		(*argv)[i++] = estrdup("/bin/bash");
  175. +		(*argv)[i++] = estrdup("--php");
  176. +		(*argv)[i++] = estrdup("-rc");
  177. +		(*argv)[i++] = estrdup("exec \"$@\"");
  178. +		(*argv)[i++] = estrdup("bash");
  179. +		(*argv)[i] = NULL;
  180. +	}
  181.  
  182.  	ZEND_HASH_FOREACH_VAL(array, arg_zv) {
  183.  		zend_string *arg_str = get_valid_arg_string(arg_zv, i + 1);
  184. @@ -1278,6 +1288,17 @@
  185.  	}
  186.  #endif
  187.  
  188. +	zval envpath;
  189. +	if (PG(exec_dir) && strlen(PG(exec_dir))) {
  190. +		if (!environment) {
  191. +			ALLOC_HASHTABLE(environment);
  192. +			zend_hash_init(environment, 1, NULL, NULL, 0);
  193. +		}
  194. +		zval tmp;
  195. +		ZVAL_STRING(&tmp, PG(exec_dir));
  196. +		zend_hash_str_add(environment, "PATH", strlen("PATH"), &tmp);
  197. +	}
  198. +
  199.  	if (environment) {
  200.  		env = php_array_to_envp(environment);
  201.  	}
  202. @@ -1403,9 +1422,15 @@
  203.  	if (argv) {
  204.  		r = posix_spawnp(&child, ZSTR_VAL(command_str), &factions, NULL, argv, (env.envarray ? env.envarray : environ));
  205.  	} else {
  206. -		r = posix_spawn(&child, "/bin/sh" , &factions, NULL,
  207. -				(char * const[]) {"sh", "-c", ZSTR_VAL(command_str), NULL},
  208. -				env.envarray ? env.envarray : environ);
  209. +		if (PG(exec_dir) && strlen(PG(exec_dir))) {
  210. +			r = posix_spawn(&child, "/bin/bash" , &factions, NULL,
  211. +					(char * const[]) {"bash", "--php", "-rc", ZSTR_VAL(command_str), NULL},
  212. +					env.envarray ? env.envarray : environ);
  213. +		} else {
  214. +			r = posix_spawn(&child, "/bin/sh" , &factions, NULL,
  215. +					(char * const[]) {"sh", "-c", ZSTR_VAL(command_str), NULL},
  216. +					env.envarray ? env.envarray : environ);
  217. +		}
  218.  	}
  219.  	posix_spawn_file_actions_destroy(&factions);
  220.  	if (r != 0) {
  221. @@ -1438,10 +1463,14 @@
  222.  			}
  223.  			execvp(ZSTR_VAL(command_str), argv);
  224.  		} else {
  225. -			if (env.envarray) {
  226. -				execle("/bin/sh", "sh", "-c", ZSTR_VAL(command_str), NULL, env.envarray);
  227. +			if (PG(exec_dir) && strlen(PG(exec_dir))) {
  228. +				execle("/bin/bash", "bash", "--php", "-rc", ZSTR_VAL(command_str), NULL, env.envarray);
  229.  			} else {
  230. -				execl("/bin/sh", "sh", "-c", ZSTR_VAL(command_str), NULL);
  231. +				if (env.envarray) {
  232. +					execle("/bin/sh", "sh", "-c", ZSTR_VAL(command_str), NULL, env.envarray);
  233. +				} else {
  234. +					execl("/bin/sh", "sh", "-c", ZSTR_VAL(command_str), NULL);
  235. +				}
  236.  			}
  237.  		}
  238.  
  239. diff -Naur a/main/main.c b/main/main.c
  240. --- a/main/main.c	2025-09-09 13:09:59.000000000 +0200
  241. +++ b/main/main.c	2025-09-16 21:32:25.598400849 +0200
  242. @@ -886,6 +886,7 @@
  243.  	STD_PHP_INI_ENTRY("syslog.facility",		"LOG_USER",		PHP_INI_SYSTEM,		OnSetFacility,		syslog_facility,	php_core_globals,		core_globals)
  244.  	STD_PHP_INI_ENTRY("syslog.ident",		"php",			PHP_INI_SYSTEM,		OnUpdateString,		syslog_ident,		php_core_globals,		core_globals)
  245.  	STD_PHP_INI_ENTRY("syslog.filter",		"no-ctrl",		PHP_INI_ALL,		OnSetLogFilter,		syslog_filter,		php_core_globals, 		core_globals)
  246. +	STD_PHP_INI_ENTRY("exec_dir",			NULL,		PHP_INI_SYSTEM,		OnUpdateString,		exec_dir,		php_core_globals,		core_globals)
  247.  PHP_INI_END()
  248.  /* }}} */
  249.  
  250. diff -Naur a/main/php_globals.h b/main/php_globals.h
  251. --- a/main/php_globals.h	2025-09-09 13:09:59.000000000 +0200
  252. +++ b/main/php_globals.h	2025-09-16 21:32:25.598400849 +0200
  253. @@ -173,6 +173,8 @@
  254.  	char *syslog_ident;
  255.  	zend_long syslog_filter;
  256.  	zend_long error_log_mode;
  257. +
  258. +	char *exec_dir;
  259.  };
  260.  
  261.  
  262. diff -Naur a/php.ini-development b/php.ini-development
  263. --- a/php.ini-development	2025-09-09 13:09:59.000000000 +0200
  264. +++ b/php.ini-development	2025-09-16 21:32:25.599400843 +0200
  265. @@ -317,6 +317,10 @@
  266.  ; https://php.net/open-basedir
  267.  ;open_basedir =
  268.  
  269. +; Only executables located in the exec_dir will be allowed to be executed
  270. +; via the exec family of functions.
  271. +exec_dir =
  272. +
  273.  ; This directive allows you to disable certain functions.
  274.  ; It receives a comma-delimited list of function names.
  275.  ; https://php.net/disable-functions
  276. diff -Naur a/php.ini-production b/php.ini-production
  277. --- a/php.ini-production	2025-09-09 13:09:59.000000000 +0200
  278. +++ b/php.ini-production	2025-09-16 21:32:25.599400843 +0200
  279. @@ -317,6 +317,10 @@
  280.  ; https://php.net/open-basedir
  281.  ;open_basedir =
  282.  
  283. +; Only executables located in the exec_dir will be allowed to be executed
  284. +; via the exec family of functions.
  285. +exec_dir =
  286. +
  287.  ; This directive allows you to disable certain functions.
  288.  ; It receives a comma-delimited list of function names.
  289.  ; https://php.net/disable-functions
  290.