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)
(cherry picked from commit 2e07a3a)
(cherry picked from commit a6c1c62)
(cherry picked from commit 46b570a)

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

@@ -59,6 +59,21 @@ PHPAPI void php_register_variable_safe(char *var, char *strval, size_t str_len,
 	php_register_variable_ex(var, &new_entry, track_vars_array);
 }
 
+/* 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 zend_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 1;
+	}
+
+	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 1;
+	}
+
+	return 0;
+}
+
 PHPAPI void php_register_variable_ex(char *var_name, zval *val, zval *track_vars_array)
 {
 	char *p = NULL;
@@ -109,20 +124,6 @@ PHPAPI void php_register_variable_ex(char *var_name, zval *val, zval *track_vars
 	}
 	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_dtor(val);
 		free_alloca(var_orig, use_heap);
@@ -220,6 +221,12 @@ PHPAPI void php_register_variable_ex(char *var_name, zval *val, zval *track_vars
 					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(char *var_name, zval *val, zval *track_vars
 				zval_ptr_dtor(&gpc_element);
 			}
 		} else {
+			if (php_is_forbidden_variable_name(index, index_len, var_name)) {
+				zval_ptr_dtor_nogc(val);
+				free_alloca(var_orig, use_heap);
+				return;
+			}
+
 			/*
 			 * According to rfc2965, more specific paths are listed above the less specific ones.
 			 * If we encounter a duplicate cookie name, we should skip it, since it is not possible