mirror of
https://github.com/netbirdio/gvisor.git
synced 2026-05-22 17:12:49 -07:00
Andrei Vagin
1864d9d091
Top-Byte-Ignore (TBI) is a feature on all ARMv8.0 CPUs that causes the top byte
of virtual addresses to be ignored on loads and stores. Instead, bit 55 is
extended over bits 56-63 before address translation. This feature allows use of
the (ignored) top byte as a tag or for other in-band metadata.
In Linux, brk()/mmap()/mremap() syscalls don't untag addresses. More details
are in dcde237319e6 ("mm: Avoid creating virtual address aliases in
brk()/mmap()/mremap()")
PiperOrigin-RevId: 715885990
97 lines
2.7 KiB
C++
97 lines
2.7 KiB
C++
// Copyright 2018 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#define _GNU_SOURCE 1
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#include <signal.h>
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#include <sys/mman.h>
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#include <ucontext.h>
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#include <unistd.h>
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#include "gtest/gtest.h"
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#include "test/util/test_util.h"
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namespace gvisor {
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namespace testing {
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namespace {
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__attribute__((noinline)) void Fault(void) {
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volatile int* foo = nullptr;
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*foo = 0;
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}
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int GetPcFromUcontext(ucontext_t* uc, uintptr_t* pc) {
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#if defined(__x86_64__)
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*pc = uc->uc_mcontext.gregs[REG_RIP];
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return 1;
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#elif defined(__i386__)
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*pc = uc->uc_mcontext.gregs[REG_EIP];
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return 1;
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#elif defined(__aarch64__)
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*pc = uc->uc_mcontext.pc;
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return 1;
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#else
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return 0;
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#endif
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}
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void sigact_handler(int sig, siginfo_t* siginfo, void* context) {
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uintptr_t pc;
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if (GetPcFromUcontext(reinterpret_cast<ucontext_t*>(context), &pc)) {
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/* Expect Fault() to be at most 64 bytes in size. */
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uintptr_t fault_addr = reinterpret_cast<uintptr_t>(&Fault);
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EXPECT_GE(pc, fault_addr);
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EXPECT_LT(pc, fault_addr + 64);
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// The following file is used to detect tests that exit prematurely. Since
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// we need to call exit() here, delete the file by hand.
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const char* exit_file = getenv("TEST_PREMATURE_EXIT_FILE");
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if (exit_file != nullptr) {
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ASSERT_THAT(unlink(exit_file), SyscallSucceeds());
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}
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exit(0);
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}
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}
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#if defined(__aarch64__)
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#define APPLY_ADDRESS_TAG(addr) ((void*)((uint64_t)addr | (1ULL << 57)))
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TEST(TaggedAddressesTest, MemoryFault) {
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void* addr = mmap(0, kPageSize, PROT_READ | PROT_WRITE,
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MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
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ASSERT_NE(addr, MAP_FAILED);
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addr = APPLY_ADDRESS_TAG(addr);
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((uint64_t*)addr)[0] =
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5; // trigger a memory fault that is handled in the Sentry.
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EXPECT_THAT(munmap(addr, kPageSize), SyscallSucceeds());
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}
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#endif
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TEST(FaultTest, InRange) {
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// Reset the signal handler to do nothing so that it doesn't freak out
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// the test runner when we fire an alarm.
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struct sigaction sa = {};
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sa.sa_sigaction = sigact_handler;
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sigfillset(&sa.sa_mask);
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sa.sa_flags = SA_SIGINFO;
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ASSERT_THAT(sigaction(SIGSEGV, &sa, nullptr), SyscallSucceeds());
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Fault();
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}
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} // namespace
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} // namespace testing
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} // namespace gvisor
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