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/*
* Copyright (C) 2020 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.
*/
#include <signal.h>
#include <stdio.h>
#include <sys/auxv.h>
#include <sys/cdefs.h>
#include <sys/mman.h>
#include <unistd.h>
#include <memory>
void action(int signo, siginfo_t* info __unused, void*) {
#ifdef __ANDROID__
if (signo == 11 && info->si_code == SEGV_MTEAERR) {
fprintf(stderr, "SEGV_MTEAERR\n");
_exit(0);
}
if (signo == 11 && info->si_code == SEGV_MTESERR) {
fprintf(stderr, "SEGV_MTESERR\n");
_exit(0);
}
#endif
fprintf(stderr, "signo %d\n", signo);
_exit(0);
}
void action2(int signo, siginfo_t* info __unused, void*) {
fprintf(stderr, "unexpected signal %d\n", signo);
_exit(0);
}
__attribute__((optnone)) int main() {
struct sigaction sa = {};
sa.sa_sigaction = action;
sa.sa_flags = SA_SIGINFO;
sigaction(SIGSEGV, &sa, nullptr);
std::unique_ptr<int[]> p = std::make_unique<int[]>(4);
volatile int oob = p[-1];
(void)oob;
#if defined(__BIONIC__) && defined(__aarch64__)
// If we get here, bad access on system heap memory did not trigger a fault.
// This suggests that MTE is disabled. Make sure that explicitly tagged PROT_MTE memory does not
// trigger a fault either.
if (getauxval(AT_HWCAP2) & HWCAP2_MTE) {
sa.sa_sigaction = action2;
sigaction(SIGSEGV, &sa, nullptr);
size_t page_size = static_cast<size_t>(sysconf(_SC_PAGESIZE));
void* p = mmap(nullptr, page_size, PROT_READ | PROT_WRITE | PROT_MTE,
MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
if (!p) {
fprintf(stderr, "mmap failed\n");
return 1;
}
void* q = p;
__asm__ __volatile__(
".arch_extension memtag\n"
"irg %[Ptr], %[Ptr], xzr\n"
"stg %[Ptr], [%[Ptr]]\n"
"addg %[Ptr], %[Ptr], 0, 1\n"
"str xzr, [%[Ptr]]\n"
: [Ptr] "+&r"(q)
:
: "memory");
munmap(p, page_size);
}
#endif // __aarch64__
fprintf(stderr, "normal exit\n");
return 0;
}
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