Fix GHSA-5hqh-c84r-qjcv: Integer overflow in the firebird quoter causing OOB writes

(cherry picked from commit 69c5f68fdc3deed9ebce2cc44b4bf5e0c47cd28f)
(cherry picked from commit b4f73be)
(cherry picked from commit 0530cbf)
(cherry picked from commit 72d4c4e)
(cherry picked from commit 8a4f389)

Author: nielsdos

ext/pdo_firebird/firebird_driver.c

@@ -290,7 +290,7 @@ static zend_long firebird_handle_doer(pdo_dbh_t *dbh, const char *sql, size_t sq
 static int firebird_handle_quoter(pdo_dbh_t *dbh, const char *unquoted, size_t unquotedlen, /* {{{ */
 	char **quoted, size_t *quotedlen, enum pdo_param_type paramtype)
 {
-	int qcount = 0;
+	size_t qcount = 0;
 	char const *co, *l, *r;
 	char *c;
 
@@ -305,6 +305,10 @@ static int firebird_handle_quoter(pdo_dbh_t *dbh, const char *unquoted, size_t u
 	/* count the number of ' characters */
 	for (co = unquoted; (co = strchr(co,'\'')); qcount++, co++);
 
+	if (UNEXPECTED(unquotedlen + 2 > ZSTR_MAX_LEN - qcount)) {
+		return 0;
+	}
+
 	*quotedlen = unquotedlen + qcount + 2;
 	*quoted = c = emalloc(*quotedlen+1);
 	*c++ = '\'';