Merge branch 'PHP-7.3' into PHP-7.4

* PHP-7.3:
  Update NEWS
  Fix bug #79037 (global buffer-overflow in `mbfl_filt_conv_big5_wchar`)
  Fix #79099: OOB read in php_strip_tags_ex
  Fix #79091: heap use-after-free in session_create_id()

Author: smalyshev

ext/mbstring/libmbfl/filters/mbfilter_big5.c

@@ -145,10 +145,10 @@ static unsigned short cp950_pua_tbl[][4] = {
 static inline int is_in_cp950_pua(int c1, int c) {
 	if ((c1 >= 0xfa && c1 <= 0xfe) || (c1 >= 0x8e && c1 <= 0xa0) ||
 			(c1 >= 0x81 && c1 <= 0x8d) || (c1 >= 0xc7 && c1 <= 0xc8)) {
-		return (c > 0x39 && c < 0x7f) || (c > 0xa0 && c < 0xff);
+		return (c >=0x40 && c <= 0x7e) || (c >= 0xa1 && c <= 0xfe);
 	}
 	if (c1 == 0xc6) {
-		return c > 0xa0 && c < 0xff;
+		return c >= 0xa1 && c <= 0xfe;
 	}
 	return 0;
 }

ext/mbstring/tests/bug79037.phpt

@@ -0,0 +1,10 @@
+--TEST--
+Bug #79037: global buffer-overflow in `mbfl_filt_conv_big5_wchar`
+--FILE--
+<?php
+
+var_dump(mb_convert_encoding("\x81\x3a", "UTF-8", "CP950"));
+
+?>
+--EXPECT--
+string(1) "?"

ext/session/session.c

@@ -2296,6 +2296,7 @@ static PHP_FUNCTION(session_create_id)
 				/* Detect collision and retry */
 				if (PS(mod)->s_validate_sid(&PS(mod_data), new_id) == FAILURE) {
 					zend_string_release_ex(new_id, 0);
+                    new_id = NULL;
 					continue;
 				}
 				break;

ext/session/tests/bug79091.phpt

@@ -0,0 +1,67 @@
+--TEST--
+Bug #79091 (heap use-after-free in session_create_id())
+--SKIPIF--
+<?php
+if (!extension_loaded('session')) die('skip session extension not available');
+?>
+--FILE--
+<?php
+class MySessionHandler implements SessionHandlerInterface, SessionIdInterface, SessionUpdateTimestampHandlerInterface
+{
+    public function close()
+    {
+        return true;
+    }
+
+    public function destroy($session_id)
+    {
+        return true;
+    }
+
+    public function gc($maxlifetime)
+    {
+        return true;
+    }
+
+    public function open($save_path, $session_name)
+    {
+        return true;
+    }
+
+    public function read($session_id)
+    {
+        return '';
+    }
+
+    public function write($session_id, $session_data)
+    {
+        return true;
+    }
+
+    public function create_sid()
+    {
+        return uniqid();
+    }
+
+    public function updateTimestamp($key, $val)
+    {
+        return true;
+    }
+
+    public function validateId($key)
+    {
+        return false;
+    }
+}
+
+ob_start();
+var_dump(session_set_save_handler(new MySessionHandler()));
+var_dump(session_start());
+ob_flush();
+session_create_id();
+?>
+--EXPECTF--
+bool(true)
+bool(true)
+
+Warning: session_create_id(): Failed to create new ID in %s on line %d

ext/standard/string.c

@@ -5278,7 +5278,7 @@ PHPAPI size_t php_strip_tags_ex(char *rbuf, size_t len, uint8_t *stateptr, const
 			}
 
 			lc = '>';
-			if (is_xml && *(p -1) == '-') {
+			if (is_xml && p >= buf + 1 && *(p -1) == '-') {
 				break;
 			}
 			in_q = state = is_xml = 0;
@@ -5310,7 +5310,7 @@ PHPAPI size_t php_strip_tags_ex(char *rbuf, size_t len, uint8_t *stateptr, const
 			goto reg_char_1;
 		case '!':
 			/* JavaScript & Other HTML scripting languages */
-			if (*(p-1) == '<') {
+			if (p >= buf + 1 && *(p-1) == '<') {
 				state = 3;
 				lc = c;
 				p++;
@@ -5320,7 +5320,7 @@ PHPAPI size_t php_strip_tags_ex(char *rbuf, size_t len, uint8_t *stateptr, const
 			}
 			break;
 		case '?':
-			if (*(p-1) == '<') {
+			if (p >= buf + 1 && *(p-1) == '<') {
 				br=0;
 				state = 2;
 				p++;

ext/standard/tests/file/bug79099.phpt

@@ -0,0 +1,32 @@
+--TEST--
+Bug #79099 (OOB read in php_strip_tags_ex)
+--FILE--
+<?php
+$stream = fopen('php://memory', 'w+');
+fputs($stream, "<?\n\"\n");
+rewind($stream);
+var_dump(@fgetss($stream));
+var_dump(@fgetss($stream));
+fclose($stream);
+
+$stream = fopen('php://memory', 'w+');
+fputs($stream, "<\0\n!\n");
+rewind($stream);
+var_dump(@fgetss($stream));
+var_dump(@fgetss($stream));
+fclose($stream);
+
+$stream = fopen('php://memory', 'w+');
+fputs($stream, "<\0\n?\n");
+rewind($stream);
+var_dump(@fgetss($stream));
+var_dump(@fgetss($stream));
+fclose($stream);
+?>
+--EXPECT--
+string(0) ""
+string(0) ""
+string(0) ""
+string(0) ""
+string(0) ""
+string(0) ""