crashpad/minidump/minidump_context_writer_test.cc
Alex Gough 9e0051aba6 Write compacted xsave contexts in minidumps
Adds new structures and offsets for minidump extended contexts. This
information will be captured from threads in a later CL so this CL
does not yet write different dumps, except in testing.

Minidump format for extended compacted contexts has been determined by
experiment. Offsets for where to write various parts of the context
are hardcoded to 0x550 as this matches values seen in Windows. Offsets
for misc_info_5 match those seen in working minidumps that can be opened
in windbg. Our hope is that while these could change in future, CPU
and OS vendors are unlikely to change them.

See doc[0] for a discussion of these fields and offsets in the minidump.

See "MANAGING STATE USING THE XSAVE FEATURE SET" Chapter 13 in the
Intel SDM[1]. Many of the offsets and sizes of the extended features
are provided by cpu specific values. We can access these in Windows
using the SDK, and transfer these to the saved extended context
which in turn is understandable by windbg.

Further information is available from AMD Ch. 18 "Shadow Stacks"[2].

    [0] https://docs.google.com/document/d/1Dn8n97r5B7kxYouvujNnPIYd_7QeVHpahSRmB92Qn6g/edit#heading=h.hivqj2jg39y
    [1] https://software.intel.com/content/www/us/en/develop/download/intel-64-and-ia-32-architectures-sdm-combined-volumes-1-2a-2b-2c-2d-3a-3b-3c-3d-and-4.html.
    [2] https://www.amd.com/system/files/TechDocs/24593.pdf

Bug: 1250098
Change-Id: Ia9041acc379c6d38329ee99737a2a0a77f7a1ee0
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/3536964
Reviewed-by: Joshua Peraza <jperaza@chromium.org>
Commit-Queue: Alex Gough <ajgo@chromium.org>
2022-05-17 01:45:56 +00:00

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// Copyright 2014 The Crashpad Authors. All rights reserved.
//
// 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 "minidump/minidump_context_writer.h"
#include <stdint.h>
#include "gtest/gtest.h"
#include "minidump/minidump_context.h"
#include "minidump/test/minidump_context_test_util.h"
#include "minidump/test/minidump_writable_test_util.h"
#include "snapshot/cpu_context.h"
#include "snapshot/test/test_cpu_context.h"
#include "util/file/string_file.h"
namespace crashpad {
namespace test {
namespace {
template <typename Writer, typename Context>
void EmptyContextTest(void (*expect_context)(uint32_t, const Context*, bool)) {
Writer context_writer;
StringFile string_file;
EXPECT_TRUE(context_writer.WriteEverything(&string_file));
ASSERT_EQ(string_file.string().size(), sizeof(Context));
const Context* observed =
MinidumpWritableAtRVA<Context>(string_file.string(), 0);
ASSERT_TRUE(observed);
expect_context(0, observed, false);
}
TEST(MinidumpContextWriter, MinidumpContextX86Writer) {
StringFile string_file;
{
// Make sure that a context writer thats untouched writes a zeroed-out
// context.
SCOPED_TRACE("zero");
EmptyContextTest<MinidumpContextX86Writer, MinidumpContextX86>(
ExpectMinidumpContextX86);
}
{
SCOPED_TRACE("nonzero");
string_file.Reset();
constexpr uint32_t kSeed = 0x8086;
MinidumpContextX86Writer context_writer;
InitializeMinidumpContextX86(context_writer.context(), kSeed);
EXPECT_TRUE(context_writer.WriteEverything(&string_file));
ASSERT_EQ(string_file.string().size(), sizeof(MinidumpContextX86));
const MinidumpContextX86* observed =
MinidumpWritableAtRVA<MinidumpContextX86>(string_file.string(), 0);
ASSERT_TRUE(observed);
ExpectMinidumpContextX86(kSeed, observed, false);
}
}
TEST(MinidumpContextWriter, MinidumpContextAMD64Writer) {
{
// Make sure that a heap-allocated context writer has the proper alignment,
// because it may be nonstandard.
auto context_writer = std::make_unique<MinidumpContextAMD64Writer>();
EXPECT_EQ(reinterpret_cast<uintptr_t>(context_writer.get()) &
(alignof(MinidumpContextAMD64Writer) - 1),
0u);
}
StringFile string_file;
{
// Make sure that a context writer thats untouched writes a zeroed-out
// context.
SCOPED_TRACE("zero");
EmptyContextTest<MinidumpContextAMD64Writer, MinidumpContextAMD64>(
ExpectMinidumpContextAMD64);
}
{
SCOPED_TRACE("nonzero");
string_file.Reset();
constexpr uint32_t kSeed = 0x808664;
MinidumpContextAMD64Writer context_writer;
InitializeMinidumpContextAMD64(context_writer.context(), kSeed);
EXPECT_TRUE(context_writer.WriteEverything(&string_file));
ASSERT_EQ(string_file.string().size(), sizeof(MinidumpContextAMD64));
const MinidumpContextAMD64* observed =
MinidumpWritableAtRVA<MinidumpContextAMD64>(string_file.string(), 0);
ASSERT_TRUE(observed);
ExpectMinidumpContextAMD64(kSeed, observed, false);
}
}
template <typename Writer, typename Context>
void FromSnapshotTest(const CPUContext& snapshot_context,
void (*expect_context)(uint32_t, const Context*, bool),
uint32_t seed) {
std::unique_ptr<MinidumpContextWriter> context_writer =
MinidumpContextWriter::CreateFromSnapshot(&snapshot_context);
ASSERT_TRUE(context_writer);
StringFile string_file;
ASSERT_TRUE(context_writer->WriteEverything(&string_file));
const Context* observed =
MinidumpWritableAtRVA<Context>(string_file.string(), 0);
ASSERT_TRUE(observed);
expect_context(seed, observed, true);
}
TEST(MinidumpContextWriter, X86_FromSnapshot) {
constexpr uint32_t kSeed = 32;
CPUContextX86 context_x86;
CPUContext context;
context.x86 = &context_x86;
InitializeCPUContextX86(&context, kSeed);
FromSnapshotTest<MinidumpContextX86Writer, MinidumpContextX86>(
context, ExpectMinidumpContextX86, kSeed);
}
TEST(MinidumpContextWriter, AMD64_FromSnapshot) {
constexpr uint32_t kSeed = 64;
CPUContextX86_64 context_x86_64;
CPUContext context;
context.x86_64 = &context_x86_64;
InitializeCPUContextX86_64(&context, kSeed);
FromSnapshotTest<MinidumpContextAMD64Writer, MinidumpContextAMD64>(
context, ExpectMinidumpContextAMD64, kSeed);
}
TEST(MinidumpContextWriter, AMD64_CetFromSnapshot) {
constexpr uint32_t kSeed = 77;
CPUContextX86_64 context_x86_64;
CPUContext context;
context.x86_64 = &context_x86_64;
InitializeCPUContextX86_64(&context, kSeed);
context_x86_64.xstate.enabled_features |= XSTATE_MASK_CET_U;
context_x86_64.xstate.cet_u.cetmsr = 1;
context_x86_64.xstate.cet_u.ssp = kSeed * kSeed;
// We cannot use FromSnapshotTest as we write more than the fixed context.
std::unique_ptr<MinidumpContextWriter> context_writer =
MinidumpContextWriter::CreateFromSnapshot(&context);
ASSERT_TRUE(context_writer);
StringFile string_file;
ASSERT_TRUE(context_writer->WriteEverything(&string_file));
const MinidumpContextAMD64* observed =
MinidumpWritableAtRVA<MinidumpContextAMD64>(string_file.string(), 0);
ASSERT_TRUE(observed);
ExpectMinidumpContextAMD64(kSeed, observed, true);
}
TEST(MinidumpContextWriter, ARM_Zeros) {
EmptyContextTest<MinidumpContextARMWriter, MinidumpContextARM>(
ExpectMinidumpContextARM);
}
TEST(MinidumpContextWRiter, ARM64_Zeros) {
EmptyContextTest<MinidumpContextARM64Writer, MinidumpContextARM64>(
ExpectMinidumpContextARM64);
}
TEST(MinidumpContextWriter, ARM_FromSnapshot) {
constexpr uint32_t kSeed = 32;
CPUContextARM context_arm;
CPUContext context;
context.arm = &context_arm;
InitializeCPUContextARM(&context, kSeed);
FromSnapshotTest<MinidumpContextARMWriter, MinidumpContextARM>(
context, ExpectMinidumpContextARM, kSeed);
}
TEST(MinidumpContextWriter, ARM64_FromSnapshot) {
constexpr uint32_t kSeed = 64;
CPUContextARM64 context_arm64;
CPUContext context;
context.arm64 = &context_arm64;
InitializeCPUContextARM64(&context, kSeed);
FromSnapshotTest<MinidumpContextARM64Writer, MinidumpContextARM64>(
context, ExpectMinidumpContextARM64, kSeed);
}
TEST(MinidumpContextWriter, MIPS_Zeros) {
EmptyContextTest<MinidumpContextMIPSWriter, MinidumpContextMIPS>(
ExpectMinidumpContextMIPS);
}
TEST(MinidumpContextWriter, MIPS64_Zeros) {
EmptyContextTest<MinidumpContextMIPS64Writer, MinidumpContextMIPS64>(
ExpectMinidumpContextMIPS64);
}
TEST(MinidumpContextWriter, MIPS_FromSnapshot) {
constexpr uint32_t kSeed = 32;
CPUContextMIPS context_mips;
CPUContext context;
context.mipsel = &context_mips;
InitializeCPUContextMIPS(&context, kSeed);
FromSnapshotTest<MinidumpContextMIPSWriter, MinidumpContextMIPS>(
context, ExpectMinidumpContextMIPS, kSeed);
}
TEST(MinidumpContextWriter, MIPS64_FromSnapshot) {
constexpr uint32_t kSeed = 64;
CPUContextMIPS64 context_mips;
CPUContext context;
context.mips64 = &context_mips;
InitializeCPUContextMIPS64(&context, kSeed);
FromSnapshotTest<MinidumpContextMIPS64Writer, MinidumpContextMIPS64>(
context, ExpectMinidumpContextMIPS64, kSeed);
}
} // namespace
} // namespace test
} // namespace crashpad