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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	2025-10-21 16:53:41.000000000 +0200
  11. +++ b/ext/standard/exec.c	2025-11-14 21:04:45.766282203 +0100
  12. @@ -116,21 +116,30 @@
  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)() = NULL;
  22.  #endif
  23.  
  24. +	if (PG(exec_dir) && strlen(PG(exec_dir))) {
  25. +		zend_string *cmd_esc = php_escape_shell_arg(cmd);
  26. +		spprintf(&d, 0, "PATH=%s /bin/bash --php -rc %s", PG(exec_dir), ZSTR_VAL(cmd_esc));
  27. +		zend_string_release(cmd_esc);
  28. +		cmd_p = d;
  29. +	} else {
  30. +		cmd_p = cmd;
  31. +	}
  32. +
  33.  #if PHP_SIGCHILD
  34.  	sig_handler = signal (SIGCHLD, SIG_DFL);
  35.  #endif
  36.  
  37.  #ifdef PHP_WIN32
  38. -	fp = VCWD_POPEN(cmd, "rb");
  39. +	fp = VCWD_POPEN(cmd_p, "rb");
  40.  #else
  41. -	fp = VCWD_POPEN(cmd, "r");
  42. +	fp = VCWD_POPEN(cmd_p, "r");
  43.  #endif
  44.  	if (!fp) {
  45.  		php_error_docref(NULL, E_WARNING, "Unable to fork [%s]", cmd);
  46. @@ -513,7 +522,7 @@
  47.  PHP_FUNCTION(shell_exec)
  48.  {
  49.  	FILE *in;
  50. -	char *command;
  51. +	char *command, *command_p;
  52.  	size_t command_len;
  53.  	zend_string *ret;
  54.  	php_stream *stream;
  55. @@ -531,14 +540,24 @@
  56.  		RETURN_THROWS();
  57.  	}
  58.  
  59. +	if (PG(exec_dir) && strlen(PG(exec_dir))) {
  60. +		zend_string *cmd_esc = php_escape_shell_arg(command);
  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. +	} 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	2025-10-21 16:53:41.000000000 +0200
  83. +++ b/ext/standard/file.c	2025-11-14 21:04:45.766282203 +0100
  84. @@ -825,7 +825,16 @@
  85.  		RETURN_THROWS();
  86.  	}
  87.  
  88. -	fp = VCWD_POPEN(command, posix_mode);
  89. +	if (PG(exec_dir) && strlen(PG(exec_dir))) {
  90. +		zend_string *cmd_esc = php_escape_shell_arg(command);
  91. +		char *tmp;
  92. +		spprintf(&tmp, 0, "PATH=%s /bin/bash --php -rc %s", PG(exec_dir), ZSTR_VAL(cmd_esc));
  93. +		fp = VCWD_POPEN(tmp, posix_mode);
  94. +		efree(tmp);
  95. +		zend_string_release(cmd_esc);
  96. +	} else {
  97. +		fp = VCWD_POPEN(command, posix_mode);
  98. +	}
  99.  	if (!fp) {
  100.  		php_error_docref2(NULL, command, posix_mode, E_WARNING, "%s", strerror(errno));
  101.  		efree(posix_mode);
  102. --- a/ext/standard/filestat.c	2025-10-21 16:53:41.000000000 +0200
  103. +++ b/ext/standard/filestat.c	2025-11-14 21:04:45.766282203 +0100
  104. @@ -746,6 +746,7 @@
  105.  	zend_stat_t *stat_sb = &ssb.sb;
  106.  	int flags = 0, rmask=S_IROTH, wmask=S_IWOTH, xmask=S_IXOTH; /* access rights defaults to other */
  107.  	const char *local = NULL;
  108. +	char local_safe[MAXPATHLEN];
  109.  	php_stream_wrapper *wrapper = NULL;
  110.  
  111.  	if (IS_ACCESS_CHECK(type)) {
  112. @@ -757,7 +758,7 @@
  113.  		}
  114.  
  115.  		if ((wrapper = php_stream_locate_url_wrapper(ZSTR_VAL(filename), &local, 0)) == &php_plain_files_wrapper
  116. -				&& php_check_open_basedir(local)) {
  117. +				&& type != FS_IS_X && php_check_open_basedir(local)) {
  118.  			RETURN_FALSE;
  119.  		}
  120.  
  121. @@ -787,9 +788,25 @@
  122.  					break;
  123.  #endif
  124.  #ifdef X_OK
  125. -				case FS_IS_X:
  126. -					RETURN_BOOL(VCWD_ACCESS(file_path_to_check, X_OK) == 0);
  127. +				case FS_IS_X: {
  128. +					bool xok = (VCWD_ACCESS(file_path_to_check, X_OK) == 0);
  129. +					if (!xok && PG(exec_dir) && strlen(PG(exec_dir))) {
  130. +						if (strstr(file_path_to_check, "..")) {
  131. +							RETURN_FALSE;
  132. +						} else {
  133. +							char *b = strrchr(file_path_to_check, PHP_DIR_SEPARATOR);
  134. +							if (b) {
  135. +								snprintf(local_safe, MAXPATHLEN, "%s%s", PG(exec_dir), b);
  136. +							} else {
  137. +								snprintf(local_safe, MAXPATHLEN, "%s%c%s", PG(exec_dir), PHP_DIR_SEPARATOR, file_path_to_check);
  138. +							}
  139. +							file_path_to_check = (char *)&local_safe;
  140. +						}
  141. +						xok = (VCWD_ACCESS(file_path_to_check, X_OK) == 0);
  142. +					}
  143. +					RETURN_BOOL(xok);
  144.  					break;
  145. +				}
  146.  #endif
  147.  			}
  148.  		}
  149. --- a/ext/standard/proc_open.c	2025-10-21 16:53:41.000000000 +0200
  150. +++ b/ext/standard/proc_open.c	2025-11-14 21:05:05.225148841 +0100
  151. @@ -786,7 +786,17 @@
  152.  	zend_string *command = NULL;
  153.  	int i = 0;
  154.  
  155. -	*argv = safe_emalloc(sizeof(char *), num_elems + 1, 0);
  156. +	*argv = safe_emalloc(sizeof(char *), num_elems + 1 + 5, 0);
  157. +
  158. +	if (PG(exec_dir) && strlen(PG(exec_dir))) {
  159. +		command = zend_string_init("/bin/bash", sizeof("/bin/bash") - 1, 0);
  160. +		(*argv)[i++] = estrdup("/bin/bash");
  161. +		(*argv)[i++] = estrdup("--php");
  162. +		(*argv)[i++] = estrdup("-rc");
  163. +		(*argv)[i++] = estrdup("exec \"$@\"");
  164. +		(*argv)[i++] = estrdup("bash");
  165. +		(*argv)[i] = NULL;
  166. +	}
  167.  
  168.  	ZEND_HASH_FOREACH_VAL(array, arg_zv) {
  169.  		zend_string *arg_str = get_valid_arg_string(arg_zv, i + 1);
  170. @@ -1280,8 +1290,34 @@
  171.  	}
  172.  #endif
  173.  
  174. +	zval envpath;
  175. +	ZVAL_UNDEF(&envpath);
  176. +	if (PG(exec_dir) && strlen(PG(exec_dir))) {
  177. +		zend_string *key;
  178. +		zend_ulong idx;
  179. +		zval *val;
  180. +		uint32_t count = environment ? zend_hash_num_elements(Z_ARRVAL_P(environment)) : 0;
  181. +		array_init_size(&envpath, count + 1);
  182. +		if (count) {
  183. +			ZEND_HASH_FOREACH_KEY_VAL(Z_ARRVAL_P(environment), idx, key, val) {
  184. +				if (key) {
  185. +					zend_hash_add_new(Z_ARRVAL(envpath), key, val);
  186. +				} else {
  187. +					zend_hash_index_add_new(Z_ARRVAL(envpath), idx, val);
  188. +				}
  189. +				zval_add_ref(val);
  190. +			} ZEND_HASH_FOREACH_END();
  191. +		}
  192. +		add_assoc_string(&envpath, "PATH", PG(exec_dir));
  193. +		environment = &envpath;
  194. +	}
  195. +
  196.  	if (environment) {
  197.  		env = _php_array_to_envp(environment);
  198. +		if (!Z_ISUNDEF(envpath)) {
  199. +			zval_ptr_dtor(&envpath);
  200. +			environment = NULL;
  201. +		}
  202.  	}
  203.  
  204.  	descriptors = alloc_descriptor_array(descriptorspec);
  205. @@ -1403,9 +1439,15 @@
  206.  	if (argv) {
  207.  		r = posix_spawnp(&child, ZSTR_VAL(command_str), &factions, NULL, argv, (env.envarray ? env.envarray : environ));
  208.  	} else {
  209. -		r = posix_spawn(&child, "/bin/sh" , &factions, NULL,
  210. -				(char * const[]) {"sh", "-c", ZSTR_VAL(command_str), NULL},
  211. -				env.envarray ? env.envarray : environ);
  212. +		if (PG(exec_dir) && strlen(PG(exec_dir))) {
  213. +			r = posix_spawn(&child, "/bin/bash" , &factions, NULL,
  214. +					(char * const[]) {"bash", "--php", "-rc", ZSTR_VAL(command_str), NULL},
  215. +					env.envarray ? env.envarray : environ);
  216. +		} else {
  217. +			r = posix_spawn(&child, "/bin/sh" , &factions, NULL,
  218. +					(char * const[]) {"sh", "-c", ZSTR_VAL(command_str), NULL},
  219. +					env.envarray ? env.envarray : environ);
  220. +		}
  221.  	}
  222.  	posix_spawn_file_actions_destroy(&factions);
  223.  	if (r != 0) {
  224. @@ -1438,10 +1480,14 @@
  225.  			}
  226.  			execvp(ZSTR_VAL(command_str), argv);
  227.  		} else {
  228. -			if (env.envarray) {
  229. -				execle("/bin/sh", "sh", "-c", ZSTR_VAL(command_str), NULL, env.envarray);
  230. +			if (PG(exec_dir) && strlen(PG(exec_dir))) {
  231. +				execle("/bin/bash", "bash", "--php", "-rc", ZSTR_VAL(command_str), NULL, env.envarray);
  232.  			} else {
  233. -				execl("/bin/sh", "sh", "-c", ZSTR_VAL(command_str), NULL);
  234. +				if (env.envarray) {
  235. +					execle("/bin/sh", "sh", "-c", ZSTR_VAL(command_str), NULL, env.envarray);
  236. +				} else {
  237. +					execl("/bin/sh", "sh", "-c", ZSTR_VAL(command_str), NULL);
  238. +				}
  239.  			}
  240.  		}
  241.  
  242. --- a/main/main.c	2025-11-14 21:04:24.322429168 +0100
  243. +++ b/main/main.c	2025-11-14 21:04:45.767282196 +0100
  244. @@ -813,6 +813,7 @@
  245.  	STD_PHP_INI_ENTRY("syslog.facility",		"LOG_USER",		PHP_INI_SYSTEM,		OnSetFacility,		syslog_facility,	php_core_globals,		core_globals)
  246.  	STD_PHP_INI_ENTRY("syslog.ident",		"php",			PHP_INI_SYSTEM,		OnUpdateString,		syslog_ident,		php_core_globals,		core_globals)
  247.  	STD_PHP_INI_ENTRY("syslog.filter",		"no-ctrl",		PHP_INI_ALL,		OnSetLogFilter,		syslog_filter,		php_core_globals, 		core_globals)
  248. +	STD_PHP_INI_ENTRY("exec_dir",			NULL,		PHP_INI_SYSTEM,		OnUpdateString,		exec_dir,		php_core_globals,		core_globals)
  249.  PHP_INI_END()
  250.  /* }}} */
  251.  
  252. --- a/main/php_globals.h	2025-11-14 21:04:24.204429977 +0100
  253. +++ b/main/php_globals.h	2025-11-14 21:04:45.768282189 +0100
  254. @@ -173,6 +173,8 @@
  255.  	char *syslog_ident;
  256.  	zend_long syslog_filter;
  257.  	zend_long error_log_mode;
  258. +
  259. +	char *exec_dir;
  260.  };
  261.  
  262.  
  263. --- a/php.ini-development	2025-11-14 21:04:24.204429977 +0100
  264. +++ b/php.ini-development	2025-11-14 21:04:45.768282189 +0100
  265. @@ -327,6 +327,10 @@
  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. --- a/php.ini-production	2025-11-14 21:04:24.205429970 +0100
  277. +++ b/php.ini-production	2025-11-14 21:04:45.769282182 +0100
  278. @@ -327,6 +327,10 @@
  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.