Clear PAC bits in android_unsafe_frame_pointer_chase().
Bug: 172057932
Change-Id: Ie0eb4800a6699f2094070e97e5157d4e9c186097
diff --git a/libc/bionic/android_unsafe_frame_pointer_chase.cpp b/libc/bionic/android_unsafe_frame_pointer_chase.cpp
index b3b1942..a1cb3c6 100644
--- a/libc/bionic/android_unsafe_frame_pointer_chase.cpp
+++ b/libc/bionic/android_unsafe_frame_pointer_chase.cpp
@@ -29,6 +29,7 @@
#include "platform/bionic/android_unsafe_frame_pointer_chase.h"
#include "platform/bionic/mte.h"
+#include "platform/bionic/pac.h"
#include "private/bionic_defs.h"
#include "pthread_internal.h"
@@ -73,7 +74,7 @@
while (1) {
auto* frame = reinterpret_cast<frame_record*>(begin);
if (num_frames < num_entries) {
- buf[num_frames] = frame->return_addr;
+ buf[num_frames] = __bionic_clear_pac_bits(frame->return_addr);
}
++num_frames;
if (frame->next_frame < begin + sizeof(frame_record) || frame->next_frame >= end ||
diff --git a/libc/platform/bionic/pac.h b/libc/platform/bionic/pac.h
new file mode 100644
index 0000000..34efc48
--- /dev/null
+++ b/libc/platform/bionic/pac.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <stddef.h>
+
+inline uintptr_t __bionic_clear_pac_bits(uintptr_t ptr) {
+#if defined(__aarch64__)
+ register uintptr_t x30 __asm("x30") = ptr;
+ // This is a NOP on pre-Armv8.3-A architectures.
+ asm("xpaclri" : "+r"(x30));
+ return x30;
+#else
+ return ptr;
+#endif
+}