Fixed handshake response charset. (php#13470)

The character set ID included in the handshake data at the time of connection
actually only includes the lower 8 bits of the ID, so if  try to use this to specify
a character set, the corresponding character set may not exist.

In case of an invalid character set, the default character set is now used
without an error.

Fixes php#13452
Closes php#13470

Author: SakiTakamachi

NEWS

@@ -2,6 +2,9 @@ PHP                                                                        NEWS
 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 ?? ??? ????, PHP 8.2.18
 
+- MySQLnd:
+  . Fix GH-13452 (Fixed handshake response [mysqlnd]). (Saki Takamachi)
+
 - PDO:
   . Fix various PDORow bugs. (Girgias)
 

ext/mysqlnd/mysqlnd_charset.h

@@ -19,6 +19,9 @@
 #ifndef MYSQLND_CHARSET_H
 #define MYSQLND_CHARSET_H
 
+#define MYSQLND_UTF8_MB3_DEFAULT_ID 33
+#define MYSQLND_UTF8_MB4_DEFAULT_ID 45
+
 PHPAPI zend_ulong mysqlnd_cset_escape_quotes(const MYSQLND_CHARSET * const charset, char * newstr,
 											 const char * escapestr, const size_t escapestr_len);
 

ext/mysqlnd/mysqlnd_commands.c

@@ -22,6 +22,7 @@
 #include "mysqlnd_auth.h"
 #include "mysqlnd_wireprotocol.h"
 #include "mysqlnd_debug.h"
+#include "mysqlnd_charset.h"
 
 
 /* {{{ mysqlnd_command::set_option */
@@ -642,13 +643,12 @@ MYSQLND_METHOD(mysqlnd_command, handshake)(MYSQLND_CONN_DATA * const conn, const
 	conn->protocol_version	= greet_packet.protocol_version;
 	conn->server_version	= mnd_pestrdup(greet_packet.server_version, conn->persistent);
 
-	conn->greet_charset = mysqlnd_find_charset_nr(greet_packet.charset_no);
-	if (!conn->greet_charset) {
-		char * msg;
-		mnd_sprintf(&msg, 0, "Server sent charset (%d) unknown to the client. Please, report to the developers", greet_packet.charset_no);
-		SET_CLIENT_ERROR(conn->error_info, CR_NOT_IMPLEMENTED, UNKNOWN_SQLSTATE, msg);
-		mnd_sprintf_free(msg);
-		goto err;
+	const MYSQLND_CHARSET *read_charset = mysqlnd_find_charset_nr(greet_packet.charset_no);
+	if (!read_charset) {
+		greet_packet.charset_no = conn->m->get_server_version(conn) >= 50500 ? MYSQLND_UTF8_MB4_DEFAULT_ID : MYSQLND_UTF8_MB3_DEFAULT_ID;
+		conn->greet_charset = mysqlnd_find_charset_nr(greet_packet.charset_no);
+	} else {
+		conn->greet_charset = read_charset;
 	}
 
 	conn->server_capabilities 	= greet_packet.server_capabilities;