Fix #79177: FFI doesn't handle well PHP exceptions within callback

We have to error on unhandled exceptions in FFI callbacks, to avoid
passing back undefined values.

This has been discussed and agreed upon in a previous PR[1].

[1] <https://github.com/php/php-src/pull/5120>

Closes GH-6366.

diff --git a/NEWS b/NEWS
index 95de673b3f9f3ee9e6f1ef45c68d4d41dffe5d51..017896befac85033f54af34a43fd5b7038626be7 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -14,6 +14,10 @@ PHP                                                                        NEWS
 - DOM:
   . Fixed bug #80268 (loadHTML() truncates at NUL bytes). (cmb)
 
+- FFI:
+  . Fixed bug #79177 (FFI doesn't handle well PHP exceptions within callback).
+    (cmb, Dmitry, Nikita)
+
 - IMAP:
   . Fixed bug #64076 (imap_sort() does not return FALSE on failure). (cmb)
   . Fixed bug #76618 (segfault on imap_reopen). (girgias)

diff --git a/ext/ffi/ffi.c b/ext/ffi/ffi.c
index f350f91d8a3c29cd79ab7f225270fa0888dff9be..d119ea050cbf52184f78ae7585a500b4dd31173c 100644 (file)
--- a/ext/ffi/ffi.c
+++ b/ext/ffi/ffi.c
@@ -886,6 +886,10 @@ static void zend_ffi_callback_trampoline(ffi_cif* cif, void* ret, void** args, v
        }
        free_alloca(fci.params, use_heap);
 
+       if (EG(exception)) {
+               zend_error(E_ERROR, "Throwing from FFI callbacks is not allowed");
+       }
+
        ret_type = ZEND_FFI_TYPE(callback_data->type->func.ret_type);
        if (ret_type->kind != ZEND_FFI_TYPE_VOID) {
                zend_ffi_zval_to_cdata(ret, ret_type, &retval);

diff --git a/ext/ffi/tests/bug79177.phpt b/ext/ffi/tests/bug79177.phpt
new file mode 100644 (file)
index 0000000..d764437
--- /dev/null
+++ b/ext/ffi/tests/bug79177.phpt
@@ -0,0 +1,47 @@
+--TEST--
+Bug #79177 (FFI doesn't handle well PHP exceptions within callback)
+--SKIPIF--
+<?php
+require_once('skipif.inc');
+require_once('utils.inc');
+try {
+    ffi_cdef("extern void *zend_printf;", ffi_get_php_dll_name());
+} catch (Throwable $e) {
+    die('skip PHP symbols not available');
+}
+?>
+--FILE--
+<?php
+require_once('utils.inc');
+$php = ffi_cdef("
+typedef char (*zend_write_func_t)(const char *str, size_t str_length);
+extern zend_write_func_t zend_write;
+", ffi_get_php_dll_name());
+
+echo "Before\n";
+
+$originalHandler = clone $php->zend_write;
+$php->zend_write = function($str, $len): string {
+    throw new \RuntimeException('Not allowed');
+};
+try { 
+    echo "After\n";
+} catch (\Throwable $exception) {
+    // Do not output anything here, as handler is overridden
+} finally {
+    $php->zend_write = $originalHandler;
+}
+if (isset($exception)) {
+    echo $exception->getMessage(), PHP_EOL;
+}
+?>
+--EXPECTF--
+Before
+
+Warning: Uncaught RuntimeException: Not allowed in %s:%d
+Stack trace:
+#0 %s(%d): {closure}('After\n', 6)
+#1 {main}
+  thrown in %s on line %d
+
+Fatal error: Throwing from FFI callbacks is not allowed in %s on line %d