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// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "components/zucchini/reloc_elf.h"
#include <stdint.h>
#include <algorithm>
#include <memory>
#include <vector>
#include "base/numerics/safe_conversions.h"
#include "components/zucchini/address_translator.h"
#include "components/zucchini/algorithm.h"
#include "components/zucchini/image_utils.h"
#include "components/zucchini/test_utils.h"
#include "components/zucchini/type_elf.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace zucchini {
namespace {
template <class Elf_Shdr>
SectionDimensionsElf MakeSectionDimensions(const BufferRegion& region,
offset_t entry_size) {
using sh_offset_t = decltype(Elf_Shdr::sh_offset);
using sh_size_t = decltype(Elf_Shdr::sh_size);
using sh_entsize_t = decltype(Elf_Shdr::sh_entsize);
return SectionDimensionsElf{Elf_Shdr{
0, // sh_name
0, // sh_type
0, // sh_flags
0, // sh_addr
// sh_offset
base::checked_cast<sh_offset_t>(region.offset),
// sh_size
base::checked_cast<sh_size_t>(region.size),
0, // sh_link
0, // sh_info
0, // sh_addralign
// sh_entsize
base::checked_cast<sh_entsize_t>(entry_size),
}};
}
} // namespace
TEST(RelocElfTest, ReadWrite32) {
// Set up mock image: Size = 0x3000, .reloc at 0x600. RVA is 0x40000 + offset.
constexpr rva_t kBaseRva = 0x40000;
std::vector<uint8_t> image_data(0x3000, 0xFF);
// "C0 10 04 00 08 00 00 00" represents
// (r_sym, r_type, r_offset) = (0x000000, 0x08, 0x000410C0).
// r_type = 0x08 = R_386_RELATIVE, and under this r_offset is an RVA
// 0x000410C0. Zucchini does not care about r_sym.
std::vector<uint8_t> reloc_data1 = ParseHexString(
"C0 10 04 00 08 00 00 00 " // R_386_RELATIVE.
"F8 10 04 00 08 AB CD EF " // R_386_RELATIVE.
"00 10 04 00 00 AB CD EF " // R_386_NONE.
"00 10 04 00 07 AB CD EF" // R_386_JMP_SLOT.
);
BufferRegion reloc_region1 = {0x600, reloc_data1.size()};
std::copy(reloc_data1.begin(), reloc_data1.end(),
image_data.begin() + reloc_region1.lo());
std::vector<uint8_t> reloc_data2 = ParseHexString(
"BC 20 04 00 08 00 00 00 " // R_386_RELATIVE.
"A0 20 04 00 08 AB CD EF" // R_386_RELATIVE.
);
BufferRegion reloc_region2 = {0x620, reloc_data2.size()};
std::copy(reloc_data2.begin(), reloc_data2.end(),
image_data.begin() + reloc_region2.lo());
ConstBufferView image = {image_data.data(), image_data.size()};
offset_t image_size = base::checked_cast<offset_t>(image_data.size());
AddressTranslator translator;
translator.Initialize({{0, image_size, kBaseRva, image_size}});
std::vector<SectionDimensionsElf> section_dimensions{
MakeSectionDimensions<elf::Elf32_Shdr>(reloc_region1, 8),
MakeSectionDimensions<elf::Elf32_Shdr>(reloc_region2, 8)};
// Make RelocReaderElf.
auto reader = std::make_unique<RelocReaderElf>(
image, kBit32, section_dimensions, elf::R_386_RELATIVE, 0, image_size,
translator);
// Read all references and check.
std::vector<Reference> refs;
for (base::Optional<Reference> ref = reader->GetNext(); ref.has_value();
ref = reader->GetNext()) {
refs.push_back(ref.value());
}
// Only R_386_RELATIVE references are extracted. Targets are translated from
// address (e.g., 0x000420BC) to offset (e.g., 0x20BC).
std::vector<Reference> exp_refs{
{0x600, 0x10C0}, {0x608, 0x10F8}, {0x620, 0x20BC}, {0x628, 0x20A0}};
EXPECT_EQ(exp_refs, refs);
// Write reference, extract bytes and check.
MutableBufferView mutable_image(&image_data[0], image_data.size());
auto writer =
std::make_unique<RelocWriterElf>(mutable_image, kBit32, translator);
writer->PutNext({0x608, 0x1F83});
std::vector<uint8_t> exp_reloc_data1 = ParseHexString(
"C0 10 04 00 08 00 00 00 " // R_386_RELATIVE.
"83 1F 04 00 08 AB CD EF " // R_386_RELATIVE (address modified).
"00 10 04 00 00 AB CD EF " // R_386_NONE.
"00 10 04 00 07 AB CD EF " // R_386_JMP_SLOT.
);
EXPECT_EQ(exp_reloc_data1,
Sub(image_data, reloc_region1.lo(), reloc_region1.hi()));
writer->PutNext({0x628, 0x2950});
std::vector<uint8_t> exp_reloc_data2 = ParseHexString(
"BC 20 04 00 08 00 00 00 " // R_386_RELATIVE.
"50 29 04 00 08 AB CD EF" // R_386_RELATIVE (address modified).
);
EXPECT_EQ(exp_reloc_data2,
Sub(image_data, reloc_region2.lo(), reloc_region2.hi()));
}
} // namespace zucchini
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