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android_system_core/libunwindstack/tests/ElfTest.cpp
Ryan Prichard 9b8f545920 libunwindstack: Support signal frame CIEs. 
Mark a CIE with a S in its augmentation string as signal frame.
This allows the code to properly handle signal frame data if none
of the signal frame pattern matchers work.

For a signal frame, DwarfSectionImpl<AddressType>::Eval needs to
continue the unwinding even if PC is zero. A zero PC means that the
program has crashed, and we should try to recover the real PC using the
return address on the stack or LR. This behavior is tested by
UnwindOffline.signal_{x86,x86_64}, which modify the libc.so files
so that the signal frame pattern matcher fails and the CIE/FDE
data is used instead.

Test: libunwindstack_test
Change-Id: I4655b070028fd984345311a5e743796f8c30ed36
2020-10-02 16:34:14 -07:00

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/*
* Copyright (C) 2016 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 <elf.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <gmock/gmock.h>
#include <gtest/gtest.h>
#include <unwindstack/Elf.h>
#include <unwindstack/MapInfo.h>
#include <unwindstack/RegsArm.h>
#include "ElfFake.h"
#include "ElfTestUtils.h"
#include "LogFake.h"
#include "MemoryFake.h"
#if !defined(PT_ARM_EXIDX)
#define PT_ARM_EXIDX 0x70000001
#endif
namespace unwindstack {
class ElfTest : public ::testing::Test {
protected:
void SetUp() override {
memory_ = new MemoryFake;
}
void InitElf32(uint32_t machine_type) {
Elf32_Ehdr ehdr;
TestInitEhdr<Elf32_Ehdr>(&ehdr, ELFCLASS32, machine_type);
ehdr.e_phoff = 0x100;
ehdr.e_ehsize = sizeof(ehdr);
ehdr.e_phentsize = sizeof(Elf32_Phdr);
ehdr.e_phnum = 1;
ehdr.e_shentsize = sizeof(Elf32_Shdr);
if (machine_type == EM_ARM) {
ehdr.e_flags = 0x5000200;
ehdr.e_phnum = 2;
}
memory_->SetMemory(0, &ehdr, sizeof(ehdr));
Elf32_Phdr phdr;
memset(&phdr, 0, sizeof(phdr));
phdr.p_type = PT_LOAD;
phdr.p_filesz = 0x10000;
phdr.p_memsz = 0x10000;
phdr.p_flags = PF_R | PF_X;
phdr.p_align = 0x1000;
memory_->SetMemory(0x100, &phdr, sizeof(phdr));
if (machine_type == EM_ARM) {
memset(&phdr, 0, sizeof(phdr));
phdr.p_type = PT_ARM_EXIDX;
phdr.p_offset = 0x30000;
phdr.p_vaddr = 0x30000;
phdr.p_paddr = 0x30000;
phdr.p_filesz = 16;
phdr.p_memsz = 16;
phdr.p_flags = PF_R;
phdr.p_align = 0x4;
memory_->SetMemory(0x100 + sizeof(phdr), &phdr, sizeof(phdr));
}
}
void InitElf64(uint32_t machine_type) {
Elf64_Ehdr ehdr;
TestInitEhdr<Elf64_Ehdr>(&ehdr, ELFCLASS64, machine_type);
ehdr.e_phoff = 0x100;
ehdr.e_flags = 0x5000200;
ehdr.e_ehsize = sizeof(ehdr);
ehdr.e_phentsize = sizeof(Elf64_Phdr);
ehdr.e_phnum = 1;
ehdr.e_shentsize = sizeof(Elf64_Shdr);
memory_->SetMemory(0, &ehdr, sizeof(ehdr));
Elf64_Phdr phdr;
memset(&phdr, 0, sizeof(phdr));
phdr.p_type = PT_LOAD;
phdr.p_filesz = 0x10000;
phdr.p_memsz = 0x10000;
phdr.p_flags = PF_R | PF_X;
phdr.p_align = 0x1000;
memory_->SetMemory(0x100, &phdr, sizeof(phdr));
}
void VerifyStepIfSignalHandler(uint64_t load_bias);
MemoryFake* memory_;
};
TEST_F(ElfTest, invalid_memory) {
Elf elf(memory_);
ASSERT_FALSE(elf.Init());
ASSERT_FALSE(elf.valid());
}
TEST_F(ElfTest, elf_invalid) {
Elf elf(memory_);
InitElf32(EM_386);
// Corrupt the ELF signature.
memory_->SetData32(0, 0x7f000000);
ASSERT_FALSE(elf.Init());
ASSERT_FALSE(elf.valid());
ASSERT_TRUE(elf.interface() == nullptr);
ASSERT_EQ("", elf.GetSoname());
std::string name;
uint64_t func_offset;
ASSERT_FALSE(elf.GetFunctionName(0, &name, &func_offset));
ASSERT_FALSE(elf.StepIfSignalHandler(0, nullptr, nullptr));
EXPECT_EQ(ERROR_INVALID_ELF, elf.GetLastErrorCode());
bool finished;
bool is_signal_frame;
ASSERT_FALSE(elf.Step(0, nullptr, nullptr, &finished, &is_signal_frame));
EXPECT_EQ(ERROR_INVALID_ELF, elf.GetLastErrorCode());
}
TEST_F(ElfTest, elf32_invalid_machine) {
Elf elf(memory_);
InitElf32(EM_PPC);
ResetLogs();
ASSERT_FALSE(elf.Init());
ASSERT_EQ("", GetFakeLogBuf());
ASSERT_EQ("4 unwind 32 bit elf that is neither arm nor x86 nor mips: e_machine = 20\n\n",
GetFakeLogPrint());
}
TEST_F(ElfTest, elf64_invalid_machine) {
Elf elf(memory_);
InitElf64(EM_PPC64);
ResetLogs();
ASSERT_FALSE(elf.Init());
ASSERT_EQ("", GetFakeLogBuf());
ASSERT_EQ("4 unwind 64 bit elf that is neither aarch64 nor x86_64 nor mips64: e_machine = 21\n\n",
GetFakeLogPrint());
}
TEST_F(ElfTest, elf_arm) {
Elf elf(memory_);
InitElf32(EM_ARM);
ASSERT_TRUE(elf.Init());
ASSERT_TRUE(elf.valid());
ASSERT_EQ(static_cast<uint32_t>(EM_ARM), elf.machine_type());
ASSERT_EQ(ELFCLASS32, elf.class_type());
ASSERT_TRUE(elf.interface() != nullptr);
}
TEST_F(ElfTest, elf_mips) {
Elf elf(memory_);
InitElf32(EM_MIPS);
ASSERT_TRUE(elf.Init());
ASSERT_TRUE(elf.valid());
ASSERT_EQ(static_cast<uint32_t>(EM_MIPS), elf.machine_type());
ASSERT_EQ(ELFCLASS32, elf.class_type());
ASSERT_TRUE(elf.interface() != nullptr);
}
TEST_F(ElfTest, elf_x86) {
Elf elf(memory_);
InitElf32(EM_386);
ASSERT_TRUE(elf.Init());
ASSERT_TRUE(elf.valid());
ASSERT_EQ(static_cast<uint32_t>(EM_386), elf.machine_type());
ASSERT_EQ(ELFCLASS32, elf.class_type());
ASSERT_TRUE(elf.interface() != nullptr);
}
TEST_F(ElfTest, elf_arm64) {
Elf elf(memory_);
InitElf64(EM_AARCH64);
ASSERT_TRUE(elf.Init());
ASSERT_TRUE(elf.valid());
ASSERT_EQ(static_cast<uint32_t>(EM_AARCH64), elf.machine_type());
ASSERT_EQ(ELFCLASS64, elf.class_type());
ASSERT_TRUE(elf.interface() != nullptr);
}
TEST_F(ElfTest, elf_x86_64) {
Elf elf(memory_);
InitElf64(EM_X86_64);
ASSERT_TRUE(elf.Init());
ASSERT_TRUE(elf.valid());
ASSERT_EQ(static_cast<uint32_t>(EM_X86_64), elf.machine_type());
ASSERT_EQ(ELFCLASS64, elf.class_type());
ASSERT_TRUE(elf.interface() != nullptr);
}
TEST_F(ElfTest, elf_mips64) {
Elf elf(memory_);
InitElf64(EM_MIPS);
ASSERT_TRUE(elf.Init());
ASSERT_TRUE(elf.valid());
ASSERT_EQ(static_cast<uint32_t>(EM_MIPS), elf.machine_type());
ASSERT_EQ(ELFCLASS64, elf.class_type());
ASSERT_TRUE(elf.interface() != nullptr);
}
TEST_F(ElfTest, gnu_debugdata_init32) {
TestInitGnuDebugdata<Elf32_Ehdr, Elf32_Shdr>(ELFCLASS32, EM_ARM, true,
[&](uint64_t offset, const void* ptr, size_t size) {
memory_->SetMemory(offset, ptr, size);
});
Elf elf(memory_);
ASSERT_TRUE(elf.Init());
ASSERT_TRUE(elf.interface() != nullptr);
ASSERT_TRUE(elf.gnu_debugdata_interface() != nullptr);
EXPECT_EQ(0x1acU, elf.interface()->gnu_debugdata_offset());
EXPECT_EQ(0x8cU, elf.interface()->gnu_debugdata_size());
}
TEST_F(ElfTest, gnu_debugdata_init64) {
TestInitGnuDebugdata<Elf64_Ehdr, Elf64_Shdr>(ELFCLASS64, EM_AARCH64, true,
[&](uint64_t offset, const void* ptr, size_t size) {
memory_->SetMemory(offset, ptr, size);
});
Elf elf(memory_);
ASSERT_TRUE(elf.Init());
ASSERT_TRUE(elf.interface() != nullptr);
ASSERT_TRUE(elf.gnu_debugdata_interface() != nullptr);
EXPECT_EQ(0x200U, elf.interface()->gnu_debugdata_offset());
EXPECT_EQ(0x90U, elf.interface()->gnu_debugdata_size());
}
TEST_F(ElfTest, rel_pc) {
ElfFake elf(memory_);
ElfInterfaceFake* interface = new ElfInterfaceFake(memory_);
elf.FakeSetInterface(interface);
elf.FakeSetValid(true);
MapInfo map_info(nullptr, nullptr, 0x1000, 0x2000, 0, 0, "");
ASSERT_EQ(0x101U, elf.GetRelPc(0x1101, &map_info));
elf.FakeSetValid(false);
ASSERT_EQ(0x101U, elf.GetRelPc(0x1101, &map_info));
}
void ElfTest::VerifyStepIfSignalHandler(uint64_t load_bias) {
ElfFake elf(memory_);
RegsArm regs;
regs[13] = 0x50000;
regs[15] = 0x8000;
ElfInterfaceFake* interface = new ElfInterfaceFake(memory_);
elf.FakeSetInterface(interface);
elf.FakeSetLoadBias(load_bias);
memory_->SetData32(0x3000, 0xdf0027ad);
MemoryFake process_memory;
process_memory.SetData32(0x50000, 0);
for (size_t i = 0; i < 16; i++) {
process_memory.SetData32(0x500a0 + i * sizeof(uint32_t), i);
}
elf.FakeSetValid(true);
ASSERT_TRUE(elf.StepIfSignalHandler(0x3000 + load_bias, &regs, &process_memory));
EXPECT_EQ(ERROR_NONE, elf.GetLastErrorCode());
EXPECT_EQ(15U, regs.pc());
EXPECT_EQ(13U, regs.sp());
}
TEST_F(ElfTest, step_in_signal_map) {
VerifyStepIfSignalHandler(0);
}
TEST_F(ElfTest, step_in_signal_map_non_zero_load_bias) {
VerifyStepIfSignalHandler(0x1000);
}
class ElfInterfaceMock : public ElfInterface {
public:
ElfInterfaceMock(Memory* memory) : ElfInterface(memory) {}
virtual ~ElfInterfaceMock() = default;
bool Init(int64_t*) override { return false; }
void InitHeaders() override {}
std::string GetSoname() override { return ""; }
bool GetFunctionName(uint64_t, std::string*, uint64_t*) override { return false; }
std::string GetBuildID() override { return ""; }
MOCK_METHOD(bool, Step, (uint64_t, Regs*, Memory*, bool*, bool*), (override));
MOCK_METHOD(bool, GetGlobalVariable, (const std::string&, uint64_t*), (override));
MOCK_METHOD(bool, IsValidPc, (uint64_t), (override));
void MockSetDataOffset(uint64_t offset) { data_offset_ = offset; }
void MockSetDataVaddrStart(uint64_t vaddr) { data_vaddr_start_ = vaddr; }
void MockSetDataVaddrEnd(uint64_t vaddr) { data_vaddr_end_ = vaddr; }
void MockSetDynamicOffset(uint64_t offset) { dynamic_offset_ = offset; }
void MockSetDynamicVaddrStart(uint64_t vaddr) { dynamic_vaddr_start_ = vaddr; }
void MockSetDynamicVaddrEnd(uint64_t vaddr) { dynamic_vaddr_end_ = vaddr; }
};
TEST_F(ElfTest, step_in_interface) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
RegsArm regs;
ElfInterfaceMock* interface = new ElfInterfaceMock(memory_);
elf.FakeSetInterface(interface);
MemoryFake process_memory;
bool finished;
bool is_signal_frame;
EXPECT_CALL(*interface, Step(0x1000, &regs, &process_memory, &finished, &is_signal_frame))
.WillOnce(::testing::Return(true));
ASSERT_TRUE(elf.Step(0x1000, &regs, &process_memory, &finished, &is_signal_frame));
}
TEST_F(ElfTest, get_global_invalid_elf) {
ElfFake elf(memory_);
elf.FakeSetValid(false);
std::string global("something");
uint64_t offset;
ASSERT_FALSE(elf.GetGlobalVariableOffset(global, &offset));
}
TEST_F(ElfTest, get_global_valid_not_in_interface) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
ElfInterfaceMock* interface = new ElfInterfaceMock(memory_);
elf.FakeSetInterface(interface);
std::string global("something");
EXPECT_CALL(*interface, GetGlobalVariable(global, ::testing::_))
.WillOnce(::testing::Return(false));
uint64_t offset;
ASSERT_FALSE(elf.GetGlobalVariableOffset(global, &offset));
}
TEST_F(ElfTest, get_global_vaddr_in_no_sections) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
ElfInterfaceMock* interface = new ElfInterfaceMock(memory_);
elf.FakeSetInterface(interface);
std::string global("something");
EXPECT_CALL(*interface, GetGlobalVariable(global, ::testing::_))
.WillOnce(::testing::DoAll(::testing::SetArgPointee<1>(0x300), ::testing::Return(true)));
uint64_t offset;
ASSERT_FALSE(elf.GetGlobalVariableOffset(global, &offset));
}
TEST_F(ElfTest, get_global_vaddr_in_data_section) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
ElfInterfaceMock* interface = new ElfInterfaceMock(memory_);
elf.FakeSetInterface(interface);
interface->MockSetDataVaddrStart(0x500);
interface->MockSetDataVaddrEnd(0x600);
interface->MockSetDataOffset(0xa000);
std::string global("something");
EXPECT_CALL(*interface, GetGlobalVariable(global, ::testing::_))
.WillOnce(::testing::DoAll(::testing::SetArgPointee<1>(0x580), ::testing::Return(true)));
uint64_t offset;
ASSERT_TRUE(elf.GetGlobalVariableOffset(global, &offset));
EXPECT_EQ(0xa080U, offset);
}
TEST_F(ElfTest, get_global_vaddr_in_dynamic_section) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
ElfInterfaceMock* interface = new ElfInterfaceMock(memory_);
elf.FakeSetInterface(interface);
interface->MockSetDataVaddrStart(0x500);
interface->MockSetDataVaddrEnd(0x600);
interface->MockSetDataOffset(0xa000);
interface->MockSetDynamicVaddrStart(0x800);
interface->MockSetDynamicVaddrEnd(0x900);
interface->MockSetDynamicOffset(0xc000);
std::string global("something");
EXPECT_CALL(*interface, GetGlobalVariable(global, ::testing::_))
.WillOnce(::testing::DoAll(::testing::SetArgPointee<1>(0x880), ::testing::Return(true)));
uint64_t offset;
ASSERT_TRUE(elf.GetGlobalVariableOffset(global, &offset));
EXPECT_EQ(0xc080U, offset);
}
TEST_F(ElfTest, get_global_vaddr_with_tagged_pointer) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
elf.FakeSetArch(ARCH_ARM64);
ElfInterfaceMock* interface = new ElfInterfaceMock(memory_);
elf.FakeSetInterface(interface);
interface->MockSetDataVaddrStart(0x500);
interface->MockSetDataVaddrEnd(0x600);
interface->MockSetDataOffset(0xa000);
std::string global("something");
EXPECT_CALL(*interface, GetGlobalVariable(global, ::testing::_))
.WillOnce(::testing::DoAll(::testing::SetArgPointee<1>(0x8800000000000580),
::testing::Return(true)));
uint64_t offset;
ASSERT_TRUE(elf.GetGlobalVariableOffset(global, &offset));
EXPECT_EQ(0xa080U, offset);
}
TEST_F(ElfTest, get_global_vaddr_without_tagged_pointer) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
elf.FakeSetArch(ARCH_X86_64);
ElfInterfaceMock* interface = new ElfInterfaceMock(memory_);
elf.FakeSetInterface(interface);
interface->MockSetDataVaddrStart(0x8800000000000500);
interface->MockSetDataVaddrEnd(0x8800000000000600);
interface->MockSetDataOffset(0x880000000000a000);
std::string global("something");
EXPECT_CALL(*interface, GetGlobalVariable(global, ::testing::_))
.WillOnce(::testing::DoAll(::testing::SetArgPointee<1>(0x8800000000000580),
::testing::Return(true)));
uint64_t offset;
ASSERT_TRUE(elf.GetGlobalVariableOffset(global, &offset));
EXPECT_EQ(0x880000000000a080U, offset);
}
TEST_F(ElfTest, is_valid_pc_elf_invalid) {
ElfFake elf(memory_);
elf.FakeSetValid(false);
EXPECT_FALSE(elf.IsValidPc(0x100));
EXPECT_FALSE(elf.IsValidPc(0x200));
}
TEST_F(ElfTest, is_valid_pc_interface) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
ElfInterfaceMock* interface = new ElfInterfaceMock(memory_);
elf.FakeSetInterface(interface);
EXPECT_CALL(*interface, IsValidPc(0x1500)).WillOnce(::testing::Return(true));
EXPECT_TRUE(elf.IsValidPc(0x1500));
}
TEST_F(ElfTest, is_valid_pc_from_gnu_debugdata) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
ElfInterfaceMock* interface = new ElfInterfaceMock(memory_);
elf.FakeSetInterface(interface);
ElfInterfaceMock* gnu_interface = new ElfInterfaceMock(memory_);
elf.FakeSetGnuDebugdataInterface(gnu_interface);
EXPECT_CALL(*interface, IsValidPc(0x1500)).WillOnce(::testing::Return(false));
EXPECT_CALL(*gnu_interface, IsValidPc(0x1500)).WillOnce(::testing::Return(true));
EXPECT_TRUE(elf.IsValidPc(0x1500));
}
TEST_F(ElfTest, error_code_not_valid) {
ElfFake elf(memory_);
elf.FakeSetValid(false);
ErrorData error{ERROR_MEMORY_INVALID, 0x100};
elf.GetLastError(&error);
EXPECT_EQ(ERROR_MEMORY_INVALID, error.code);
EXPECT_EQ(0x100U, error.address);
}
TEST_F(ElfTest, error_code_valid) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
ElfInterfaceFake* interface = new ElfInterfaceFake(memory_);
elf.FakeSetInterface(interface);
interface->FakeSetErrorCode(ERROR_MEMORY_INVALID);
interface->FakeSetErrorAddress(0x1000);
ErrorData error{ERROR_NONE, 0};
elf.GetLastError(&error);
EXPECT_EQ(ERROR_MEMORY_INVALID, error.code);
EXPECT_EQ(0x1000U, error.address);
EXPECT_EQ(ERROR_MEMORY_INVALID, elf.GetLastErrorCode());
EXPECT_EQ(0x1000U, elf.GetLastErrorAddress());
}
} // namespace unwindstack
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