ext/sqlite3: reject NUL bytes in SQLite3::escapeString()

escapeString() used sqlite3_mprintf("%q"), which stops at the first C NUL.
PHP strings are length-aware and may embed NULs, so values such as "a\0b"
were silently truncated to "a" when interpolated into SQL. Prepared binds
pass an explicit length and are unaffected.

ext/pdo_sqlite rejected the same inputs for PDO::quote in 0a10f6d
(GH-13952), on 8.5 and up. That check consults the connection's error mode;
escapeString() is static and has no connection, so it throws instead.

Author: iliaal

ext/sqlite3/sqlite3.c

@@ -473,6 +473,11 @@ PHP_METHOD(SQLite3, escapeString)
 		RETURN_THROWS();
 	}
 
+	if (UNEXPECTED(zend_str_has_nul_byte(sql))) {
+		zend_argument_value_error(1, "must not contain null bytes");
+		RETURN_THROWS();
+	}
+
 	if (ZSTR_LEN(sql)) {
 		ret = sqlite3_mprintf("%q", ZSTR_VAL(sql));
 		if (ret) {

ext/sqlite3/tests/gh_sqlite3_escapestring_nul.phpt

@@ -0,0 +1,35 @@
+--TEST--
+SQLite3::escapeString() rejects strings with embedded NUL bytes
+--EXTENSIONS--
+sqlite3
+--FILE--
+<?php
+
+$cases = [
+    "\0",
+    "a\0b",
+    "secret\0x",
+    "foo\0\0bar",
+];
+
+foreach ($cases as $in) {
+    try {
+        SQLite3::escapeString($in);
+        echo "FAIL: no exception for ", bin2hex($in), "\n";
+    } catch (ValueError $e) {
+        echo "ValueError: ", $e->getMessage(), "\n";
+    }
+}
+
+echo "ok: ", SQLite3::escapeString("ok"), "\n";
+echo "quote: ", SQLite3::escapeString("test''%"), "\n";
+echo "empty: ", var_export(SQLite3::escapeString(""), true), "\n";
+?>
+--EXPECT--
+ValueError: SQLite3::escapeString(): Argument #1 ($string) must not contain null bytes
+ValueError: SQLite3::escapeString(): Argument #1 ($string) must not contain null bytes
+ValueError: SQLite3::escapeString(): Argument #1 ($string) must not contain null bytes
+ValueError: SQLite3::escapeString(): Argument #1 ($string) must not contain null bytes
+ok: ok
+quote: test''''%
+empty: ''