From 2515e788bc970af5afbecbfd90eb4211acada6d3 Mon Sep 17 00:00:00 2001
From: Dmitry Stogov <dmitry@zend.com>
Date: Fri, 3 Dec 2021 11:13:50 +0300
Subject: [PATCH] JIT: Fix register clobbering

Fixes oss-fuzz #41621
---
 ext/opcache/jit/zend_jit_x86.dasc  | 13 ++++++++++---
 ext/opcache/tests/jit/mod_005.phpt | 26 ++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 3 deletions(-)
 create mode 100644 ext/opcache/tests/jit/mod_005.phpt

diff --git a/ext/opcache/jit/zend_jit_x86.dasc b/ext/opcache/jit/zend_jit_x86.dasc
index 3ea6b38fa45..5f4e914a6ce 100644
--- a/ext/opcache/jit/zend_jit_x86.dasc
+++ b/ext/opcache/jit/zend_jit_x86.dasc
@@ -5000,9 +5000,6 @@ static int zend_jit_long_math_helper(dasm_State    **Dst,
 
 	if (opcode == ZEND_MOD) {
 		result_reg = ZREG_RAX;
-		if (Z_MODE(res_addr) == IS_MEM_ZVAL && Z_REG(res_addr) == ZREG_RAX) {
-			|	mov aword T1, r0 // save
-		}
 	} else if (Z_MODE(res_addr) == IS_REG) {
 		if ((opline->opcode == ZEND_SL || opline->opcode == ZEND_SR)
 		 && opline->op2_type != IS_CONST) {
@@ -5127,6 +5124,11 @@ static int zend_jit_long_math_helper(dasm_State    **Dst,
 				|	GET_ZVAL_LVAL result_reg, op1_addr
 				|	LONG_MATH ZEND_BW_AND, result_reg, tmp_addr
 			} else {
+				if (Z_MODE(res_addr) == IS_MEM_ZVAL && Z_REG(res_addr) == ZREG_RAX) {
+					|	mov aword T1, r0 // save
+				} else if (Z_MODE(res_addr) == IS_MEM_ZVAL && Z_REG(res_addr) == ZREG_RCX) {
+					|	mov aword T1, Ra(ZREG_RCX) // save
+				}
 				result_reg = ZREG_RDX;
 				if (op2_lval == -1) {
 					|	xor Ra(result_reg), Ra(result_reg)
@@ -5142,6 +5144,8 @@ static int zend_jit_long_math_helper(dasm_State    **Dst,
 				}
 				if (Z_MODE(res_addr) == IS_MEM_ZVAL && Z_REG(res_addr) == ZREG_RAX) {
 					|	mov r0, aword T1 // restore
+				} else if (Z_MODE(res_addr) == IS_MEM_ZVAL && Z_REG(res_addr) == ZREG_RCX) {
+					|	mov Ra(ZREG_RCX), aword T1 // restore
 				}
 			}
 		} else {
@@ -5183,6 +5187,9 @@ static int zend_jit_long_math_helper(dasm_State    **Dst,
 				|.code
 			}
 
+			if (Z_MODE(res_addr) == IS_MEM_ZVAL && Z_REG(res_addr) == ZREG_RAX) {
+				|	mov aword T1, r0 // save
+			}
 			result_reg = ZREG_RDX;
 			|	GET_ZVAL_LVAL ZREG_RAX, op1_addr
 			|.if X64
diff --git a/ext/opcache/tests/jit/mod_005.phpt b/ext/opcache/tests/jit/mod_005.phpt
new file mode 100644
index 00000000000..8c90f6b6ef1
--- /dev/null
+++ b/ext/opcache/tests/jit/mod_005.phpt
@@ -0,0 +1,26 @@
+--TEST--
+JIT MOD: 005
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.file_update_protection=0
+opcache.jit_buffer_size=1M
+opcache.protect_memory=1
+--FILE--
+<?php
+class Test{
+    public $prop = 32;
+}
+
+function test2($test) {
+    $test->prop %= 3;
+	return $test;
+}
+
+var_dump(test2(new Test));
+?>
+--EXPECT--
+object(Test)#1 (1) {
+  ["prop"]=>
+  int(2)
+}