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platform_system_core/libunwindstack/tests/ElfTest.cpp
Christopher Ferris f0c82e7bad Use elf offset in signal step check. 
The function StepIfSignalHandler assumed that the rel_pc passed
to it was actually an elf offset. A new version of clang created a libc.so
that has a load bias, so tests unwinding through a signal handler
would fail on arm. On other ABIs, there is unwind information that could
be used instead, so the unwind still worked.

The fix is to subtract the load bias from the rel_pc to get an elf
offset to pass to the Register StepIfSignalHandler functions. Change all
of the Register funtions to make it clear what the first parameter means.

Add a unit test for this new code. Also, add an offline test for
this case.

Bug: 145683525

Test: Ran unit tests using the new clang and the old clang.
Change-Id: I3e249653b79bcad6d3a56411a7911fde4888e9d6
2019-12-04 22:29:59 +00:00

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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;
ASSERT_FALSE(elf.Step(0, nullptr, nullptr, &finished));
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, 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*), (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;
EXPECT_CALL(*interface, Step(0x1000, &regs, &process_memory, &finished))
.WillOnce(::testing::Return(true));
ASSERT_TRUE(elf.Step(0x1000, &regs, &process_memory, &finished));
}
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, 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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