Added max_input_vars directive to prevent attacks based on hash colli…

…sions
php · Dec 14, 2011 · 4ffedc7 · 4ffedc7
1 parent 4b14c11
commit 4ffedc7
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Showing 3 changed files with 8 additions and 0 deletions.
diff --git a/main/main.c b/main/main.c
@@ -531,6 +531,7 @@ PHP_INI_BEGIN()
 	STD_PHP_INI_ENTRY("post_max_size",			"8M",		PHP_INI_SYSTEM|PHP_INI_PERDIR,		OnUpdateLong,			post_max_size,			sapi_globals_struct,sapi_globals)
 	STD_PHP_INI_ENTRY("upload_tmp_dir",			NULL,		PHP_INI_SYSTEM,		OnUpdateStringUnempty,	upload_tmp_dir,			php_core_globals,	core_globals)
 	STD_PHP_INI_ENTRY("max_input_nesting_level", "64",		PHP_INI_SYSTEM|PHP_INI_PERDIR,		OnUpdateLongGEZero,	max_input_nesting_level,			php_core_globals,	core_globals)
+	STD_PHP_INI_ENTRY("max_input_vars",			"1000",		PHP_INI_SYSTEM|PHP_INI_PERDIR,		OnUpdateLongGEZero,	max_input_vars,						php_core_globals,	core_globals)
 
 	STD_PHP_INI_ENTRY("user_dir",				NULL,		PHP_INI_SYSTEM,		OnUpdateString,			user_dir,				php_core_globals,	core_globals)
 	STD_PHP_INI_ENTRY("variables_order",		"EGPCS",	PHP_INI_SYSTEM|PHP_INI_PERDIR,		OnUpdateStringUnempty,	variables_order,		php_core_globals,	core_globals)

diff --git a/main/php_globals.h b/main/php_globals.h
@@ -146,6 +146,7 @@ struct _php_core_globals {
 	zend_bool com_initialized;
 #endif
 	long max_input_nesting_level;
+	long max_input_vars;
 	zend_bool in_user_include;
 
 	char *user_ini_filename;

diff --git a/main/php_variables.c b/main/php_variables.c
@@ -179,6 +179,9 @@ PHPAPI void php_register_variable_ex(char *var_name, zval *val, zval *track_vars
 				escaped_index = index;
 				if (zend_symtable_find(symtable1, escaped_index, index_len + 1, (void **) &gpc_element_p) == FAILURE
 					|| Z_TYPE_PP(gpc_element_p) != IS_ARRAY) {
+					if (zend_hash_num_elements(symtable1) >= PG(max_input_vars)) {
+						php_error_docref(NULL TSRMLS_CC, E_ERROR, "Input variables exceeded %ld. To increase the limit change max_input_vars in php.ini.", PG(max_input_vars));
+					}
 					MAKE_STD_ZVAL(gpc_element);
 					array_init(gpc_element);
 					zend_symtable_update(symtable1, escaped_index, index_len + 1, &gpc_element, sizeof(zval *), (void **) &gpc_element_p);
@@ -220,6 +223,9 @@ PHPAPI void php_register_variable_ex(char *var_name, zval *val, zval *track_vars
 				zend_symtable_exists(symtable1, escaped_index, index_len + 1)) {
 				zval_ptr_dtor(&gpc_element);
 			} else {
+				if (zend_hash_num_elements(symtable1) >= PG(max_input_vars)) {
+					php_error_docref(NULL TSRMLS_CC, E_ERROR, "Input variables exceeded %ld. To increase the limit change max_input_vars in php.ini.", PG(max_input_vars));
+				}
 				zend_symtable_update(symtable1, escaped_index, index_len + 1, &gpc_element, sizeof(zval *), (void **) &gpc_element_p);
 			}
 			if (escaped_index != index) {