Fix GHSA-wpj3-hf5j-x4v4: __Host-/__Secure- cookie bypass due to partial CVE-2022-31629 fix

The check happened too early as later code paths may perform more
mangling rules. Move the check downwards right before adding the actual
variable.

(cherry picked from commit 093c08af25fb323efa0c8e6154aa9fdeae3d3b53)

Author: nielsdos

ext/standard/tests/ghsa-wpj3-hf5j-x4v4.phpt

@@ -0,0 +1,63 @@
+--TEST--
+ghsa-wpj3-hf5j-x4v4 (__Host-/__Secure- cookie bypass due to partial CVE-2022-31629 fix)
+--COOKIE--
+..Host-test=ignore_1;
+._Host-test=ignore_2;
+.[Host-test=ignore_3;
+_.Host-test=ignore_4;
+__Host-test=ignore_5;
+_[Host-test=ignore_6;
+[.Host-test=ignore_7;
+[_Host-test=ignore_8;
+[[Host-test=ignore_9;
+..Host-test[]=ignore_10;
+._Host-test[]=ignore_11;
+.[Host-test[]=ignore_12;
+_.Host-test[]=ignore_13;
+__Host-test[]=legitimate_14;
+_[Host-test[]=legitimate_15;
+[.Host-test[]=ignore_16;
+[_Host-test[]=ignore_17;
+[[Host-test[]=ignore_18;
+..Secure-test=ignore_1;
+._Secure-test=ignore_2;
+.[Secure-test=ignore_3;
+_.Secure-test=ignore_4;
+__Secure-test=ignore_5;
+_[Secure-test=ignore_6;
+[.Secure-test=ignore_7;
+[_Secure-test=ignore_8;
+[[Secure-test=ignore_9;
+..Secure-test[]=ignore_10;
+._Secure-test[]=ignore_11;
+.[Secure-test[]=ignore_12;
+_.Secure-test[]=ignore_13;
+__Secure-test[]=legitimate_14;
+_[Secure-test[]=legitimate_15;
+[.Secure-test[]=ignore_16;
+[_Secure-test[]=ignore_17;
+[[Secure-test[]=ignore_18;
+--FILE--
+<?php
+var_dump($_COOKIE);
+?>
+--EXPECT--
+array(3) {
+  ["__Host-test"]=>
+  array(1) {
+    [0]=>
+    string(13) "legitimate_14"
+  }
+  ["_"]=>
+  array(2) {
+    ["Host-test["]=>
+    string(13) "legitimate_15"
+    ["Secure-test["]=>
+    string(13) "legitimate_15"
+  }
+  ["__Secure-test"]=>
+  array(1) {
+    [0]=>
+    string(13) "legitimate_14"
+  }
+}

main/php_variables.c

@@ -54,6 +54,21 @@ static zend_always_inline void php_register_variable_quick(const char *name, siz
 	zend_string_release_ex(key, 0);
 }
 
+/* Discard variable if mangling made it start with __Host-, where pre-mangling it did not start with __Host-
+ * Discard variable if mangling made it start with __Secure-, where pre-mangling it did not start with __Secure- */
+static bool php_is_forbidden_variable_name(const char *mangled_name, size_t mangled_name_len, const char *pre_mangled_name)
+{
+	if (mangled_name_len >= sizeof("__Host-")-1 && strncmp(mangled_name, "__Host-", sizeof("__Host-")-1) == 0 && strncmp(pre_mangled_name, "__Host-", sizeof("__Host-")-1) != 0) {
+		return true;
+	}
+
+	if (mangled_name_len >= sizeof("__Secure-")-1 && strncmp(mangled_name, "__Secure-", sizeof("__Secure-")-1) == 0 && strncmp(pre_mangled_name, "__Secure-", sizeof("__Secure-")-1) != 0) {
+		return true;
+	}
+
+	return false;
+}
+
 PHPAPI void php_register_variable_ex(const char *var_name, zval *val, zval *track_vars_array)
 {
 	char *p = NULL;
@@ -104,20 +119,6 @@ PHPAPI void php_register_variable_ex(const char *var_name, zval *val, zval *trac
 	}
 	var_len = p - var;
 
-	/* Discard variable if mangling made it start with __Host-, where pre-mangling it did not start with __Host- */
-	if (strncmp(var, "__Host-", sizeof("__Host-")-1) == 0 && strncmp(var_name, "__Host-", sizeof("__Host-")-1) != 0) {
-		zval_ptr_dtor_nogc(val);
-		free_alloca(var_orig, use_heap);
-		return;
-	}
-
-	/* Discard variable if mangling made it start with __Secure-, where pre-mangling it did not start with __Secure- */
-	if (strncmp(var, "__Secure-", sizeof("__Secure-")-1) == 0 && strncmp(var_name, "__Secure-", sizeof("__Secure-")-1) != 0) {
-		zval_ptr_dtor_nogc(val);
-		free_alloca(var_orig, use_heap);
-		return;
-	}
-
 	if (var_len==0) { /* empty variable name, or variable name with a space in it */
 		zval_ptr_dtor_nogc(val);
 		free_alloca(var_orig, use_heap);
@@ -221,6 +222,12 @@ PHPAPI void php_register_variable_ex(const char *var_name, zval *val, zval *trac
 					return;
 				}
 			} else {
+				if (php_is_forbidden_variable_name(index, index_len, var_name)) {
+					zval_ptr_dtor_nogc(val);
+					free_alloca(var_orig, use_heap);
+					return;
+				}
+
 				gpc_element_p = zend_symtable_str_find(symtable1, index, index_len);
 				if (!gpc_element_p) {
 					zval tmp;
@@ -258,6 +265,12 @@ PHPAPI void php_register_variable_ex(const char *var_name, zval *val, zval *trac
 				zval_ptr_dtor_nogc(val);
 			}
 		} else {
+			if (php_is_forbidden_variable_name(index, index_len, var_name)) {
+				zval_ptr_dtor_nogc(val);
+				free_alloca(var_orig, use_heap);
+				return;
+			}
+
 			zend_ulong idx;
 
 			/*