platform_bionic/tests/scs_test.cpp
Peter Collingbourne 734beec3d4 Allocate a small guard region around the shadow call stack.
This lets us do two things:

1) Make setjmp and longjmp compatible with shadow call stack.
   To avoid leaking the shadow call stack address into memory, only the
   lower log2(SCS_SIZE) bits of x18 are stored to jmp_buf. This requires
   allocating an additional guard page so that we're guaranteed to be
   able to allocate a sufficiently aligned SCS.

2) SCS overflow detection. Overflows now result in a SIGSEGV instead
   of corrupting the allocation that comes after it.

Change-Id: I04d6634f96162bf625684672a87fba8b402b7fd1
Test: bionic-unit-tests
2018-11-16 14:37:08 -08:00

39 lines
1.1 KiB
C++

/*
* Copyright (C) 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#if __has_feature(shadow_call_stack)
#include <gtest/gtest.h>
#include "private/bionic_constants.h"
int recurse2(int count);
__attribute__((weak, noinline)) int recurse1(int count) {
if (count != 0) return recurse2(count - 1) + 1;
return 0;
}
__attribute__((weak, noinline)) int recurse2(int count) {
if (count != 0) return recurse1(count - 1) + 1;
return 0;
}
TEST(scs_test, stack_overflow) {
ASSERT_EXIT(recurse1(SCS_SIZE), testing::KilledBySignal(SIGSEGV), "");
}
#endif