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android_system_core/libunwindstack/tests/MapInfoGetElfTest.cpp
Christopher Ferris 5f118519fd Add a method to share the process memory object. 
New function to create the process memory object. This allows for
a future where different remote process memory objects could be created
depending on the way remote memory can be created. Even different local
memory objects that access memory without doing any checks.

It also allows MemoryRange objects to share one single process memory object
and could help if the process memory object caches data.

Small changes to MapInfo::CreateMemory to when some errors are detected.
- Always check if the map is a device map, instead of only if the name
  is not empty.
- Check if a memory map is readable before creating the memory from process
  memory.

Bug: 23762183

Test: Ran unit tests, unwound on device using the new code.
Change-Id: I12a93c2dc19639689a528ec41c67bfac74d431b3
2017-09-05 14:30:22 -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 <errno.h>
#include <signal.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/ptrace.h>
#include <sys/types.h>
#include <unistd.h>
#include <memory>
#include <vector>
#include <android-base/file.h>
#include <android-base/test_utils.h>
#include <gtest/gtest.h>
#include <unwindstack/Elf.h>
#include <unwindstack/MapInfo.h>
#include <unwindstack/Maps.h>
#include <unwindstack/Memory.h>
#include "ElfTestUtils.h"
#include "MemoryFake.h"
namespace unwindstack {
class MapInfoGetElfTest : public ::testing::Test {
protected:
void SetUp() override {
memory_ = new MemoryFake;
process_memory_.reset(memory_);
}
template <typename Ehdr, typename Shdr>
static void InitElf(uint64_t sh_offset, Ehdr* ehdr, uint8_t class_type, uint8_t machine_type) {
memset(ehdr, 0, sizeof(*ehdr));
memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
ehdr->e_ident[EI_CLASS] = class_type;
ehdr->e_machine = machine_type;
ehdr->e_shoff = sh_offset;
ehdr->e_shentsize = sizeof(Shdr) + 100;
ehdr->e_shnum = 4;
}
const size_t kMapSize = 4096;
std::shared_ptr<Memory> process_memory_;
MemoryFake* memory_;
TemporaryFile elf_;
};
TEST_F(MapInfoGetElfTest, invalid) {
MapInfo info{.start = 0x1000, .end = 0x2000, .offset = 0, .flags = PROT_READ, .name = ""};
// The map is empty, but this should still create an invalid elf object.
std::unique_ptr<Elf> elf(info.GetElf(process_memory_, false));
ASSERT_TRUE(elf.get() != nullptr);
ASSERT_FALSE(elf->valid());
}
TEST_F(MapInfoGetElfTest, valid32) {
MapInfo info{.start = 0x3000, .end = 0x4000, .offset = 0, .flags = PROT_READ, .name = ""};
Elf32_Ehdr ehdr;
TestInitEhdr<Elf32_Ehdr>(&ehdr, ELFCLASS32, EM_ARM);
memory_->SetMemory(0x3000, &ehdr, sizeof(ehdr));
std::unique_ptr<Elf> elf(info.GetElf(process_memory_, false));
ASSERT_TRUE(elf.get() != nullptr);
ASSERT_TRUE(elf->valid());
EXPECT_EQ(static_cast<uint32_t>(EM_ARM), elf->machine_type());
EXPECT_EQ(ELFCLASS32, elf->class_type());
}
TEST_F(MapInfoGetElfTest, valid64) {
MapInfo info{.start = 0x8000, .end = 0x9000, .offset = 0, .flags = PROT_READ, .name = ""};
Elf64_Ehdr ehdr;
TestInitEhdr<Elf64_Ehdr>(&ehdr, ELFCLASS64, EM_AARCH64);
memory_->SetMemory(0x8000, &ehdr, sizeof(ehdr));
std::unique_ptr<Elf> elf(info.GetElf(process_memory_, false));
ASSERT_TRUE(elf.get() != nullptr);
ASSERT_TRUE(elf->valid());
EXPECT_EQ(static_cast<uint32_t>(EM_AARCH64), elf->machine_type());
EXPECT_EQ(ELFCLASS64, elf->class_type());
}
TEST_F(MapInfoGetElfTest, gnu_debugdata_do_not_init32) {
MapInfo info{.start = 0x4000, .end = 0x8000, .offset = 0, .flags = PROT_READ, .name = ""};
TestInitGnuDebugdata<Elf32_Ehdr, Elf32_Shdr>(ELFCLASS32, EM_ARM, false,
[&](uint64_t offset, const void* ptr, size_t size) {
memory_->SetMemory(0x4000 + offset, ptr, size);
});
std::unique_ptr<Elf> elf(info.GetElf(process_memory_, false));
ASSERT_TRUE(elf.get() != nullptr);
ASSERT_TRUE(elf->valid());
EXPECT_EQ(static_cast<uint32_t>(EM_ARM), elf->machine_type());
EXPECT_EQ(ELFCLASS32, elf->class_type());
EXPECT_TRUE(elf->gnu_debugdata_interface() == nullptr);
}
TEST_F(MapInfoGetElfTest, gnu_debugdata_do_not_init64) {
MapInfo info{.start = 0x6000, .end = 0x8000, .offset = 0, .flags = PROT_READ, .name = ""};
TestInitGnuDebugdata<Elf64_Ehdr, Elf64_Shdr>(ELFCLASS64, EM_AARCH64, false,
[&](uint64_t offset, const void* ptr, size_t size) {
memory_->SetMemory(0x6000 + offset, ptr, size);
});
std::unique_ptr<Elf> elf(info.GetElf(process_memory_, false));
ASSERT_TRUE(elf.get() != nullptr);
ASSERT_TRUE(elf->valid());
EXPECT_EQ(static_cast<uint32_t>(EM_AARCH64), elf->machine_type());
EXPECT_EQ(ELFCLASS64, elf->class_type());
EXPECT_TRUE(elf->gnu_debugdata_interface() == nullptr);
}
TEST_F(MapInfoGetElfTest, gnu_debugdata_init32) {
MapInfo info{.start = 0x2000, .end = 0x3000, .offset = 0, .flags = PROT_READ, .name = ""};
TestInitGnuDebugdata<Elf32_Ehdr, Elf32_Shdr>(ELFCLASS32, EM_ARM, true,
[&](uint64_t offset, const void* ptr, size_t size) {
memory_->SetMemory(0x2000 + offset, ptr, size);
});
std::unique_ptr<Elf> elf(info.GetElf(process_memory_, true));
ASSERT_TRUE(elf.get() != nullptr);
ASSERT_TRUE(elf->valid());
EXPECT_EQ(static_cast<uint32_t>(EM_ARM), elf->machine_type());
EXPECT_EQ(ELFCLASS32, elf->class_type());
EXPECT_TRUE(elf->gnu_debugdata_interface() != nullptr);
}
TEST_F(MapInfoGetElfTest, gnu_debugdata_init64) {
MapInfo info{.start = 0x5000, .end = 0x8000, .offset = 0, .flags = PROT_READ, .name = ""};
TestInitGnuDebugdata<Elf64_Ehdr, Elf64_Shdr>(ELFCLASS64, EM_AARCH64, true,
[&](uint64_t offset, const void* ptr, size_t size) {
memory_->SetMemory(0x5000 + offset, ptr, size);
});
std::unique_ptr<Elf> elf(info.GetElf(process_memory_, true));
ASSERT_TRUE(elf.get() != nullptr);
ASSERT_TRUE(elf->valid());
EXPECT_EQ(static_cast<uint32_t>(EM_AARCH64), elf->machine_type());
EXPECT_EQ(ELFCLASS64, elf->class_type());
EXPECT_TRUE(elf->gnu_debugdata_interface() != nullptr);
}
TEST_F(MapInfoGetElfTest, end_le_start) {
MapInfo info{.start = 0x1000, .end = 0x1000, .offset = 0, .flags = PROT_READ, .name = elf_.path};
Elf32_Ehdr ehdr;
TestInitEhdr<Elf32_Ehdr>(&ehdr, ELFCLASS32, EM_ARM);
ASSERT_TRUE(android::base::WriteFully(elf_.fd, &ehdr, sizeof(ehdr)));
std::unique_ptr<Elf> elf(info.GetElf(process_memory_, false));
ASSERT_FALSE(elf->valid());
info.elf = nullptr;
info.end = 0xfff;
elf.reset(info.GetElf(process_memory_, false));
ASSERT_FALSE(elf->valid());
// Make sure this test is valid.
info.elf = nullptr;
info.end = 0x2000;
elf.reset(info.GetElf(process_memory_, false));
ASSERT_TRUE(elf->valid());
}
// Verify that if the offset is non-zero but there is no elf at the offset,
// that the full file is used.
TEST_F(MapInfoGetElfTest, file_backed_non_zero_offset_full_file) {
MapInfo info{
.start = 0x1000, .end = 0x2000, .offset = 0x100, .flags = PROT_READ, .name = elf_.path};
std::vector<uint8_t> buffer(0x1000);
memset(buffer.data(), 0, buffer.size());
Elf32_Ehdr ehdr;
TestInitEhdr<Elf32_Ehdr>(&ehdr, ELFCLASS32, EM_ARM);
memcpy(buffer.data(), &ehdr, sizeof(ehdr));
ASSERT_TRUE(android::base::WriteFully(elf_.fd, buffer.data(), buffer.size()));
std::unique_ptr<Elf> elf(info.GetElf(process_memory_, false));
ASSERT_TRUE(elf->valid());
ASSERT_TRUE(elf->memory() != nullptr);
ASSERT_EQ(0x100U, info.elf_offset);
// Read the entire file.
memset(buffer.data(), 0, buffer.size());
ASSERT_TRUE(elf->memory()->Read(0, buffer.data(), buffer.size()));
ASSERT_EQ(0, memcmp(buffer.data(), &ehdr, sizeof(ehdr)));
for (size_t i = sizeof(ehdr); i < buffer.size(); i++) {
ASSERT_EQ(0, buffer[i]) << "Failed at byte " << i;
}
ASSERT_FALSE(elf->memory()->Read(buffer.size(), buffer.data(), 1));
}
// Verify that if the offset is non-zero and there is an elf at that
// offset, that only part of the file is used.
TEST_F(MapInfoGetElfTest, file_backed_non_zero_offset_partial_file) {
MapInfo info{
.start = 0x1000, .end = 0x2000, .offset = 0x2000, .flags = PROT_READ, .name = elf_.path};
std::vector<uint8_t> buffer(0x4000);
memset(buffer.data(), 0, buffer.size());
Elf32_Ehdr ehdr;
TestInitEhdr<Elf32_Ehdr>(&ehdr, ELFCLASS32, EM_ARM);
memcpy(&buffer[info.offset], &ehdr, sizeof(ehdr));
ASSERT_TRUE(android::base::WriteFully(elf_.fd, buffer.data(), buffer.size()));
std::unique_ptr<Elf> elf(info.GetElf(process_memory_, false));
ASSERT_TRUE(elf->valid());
ASSERT_TRUE(elf->memory() != nullptr);
ASSERT_EQ(0U, info.elf_offset);
// Read the valid part of the file.
ASSERT_TRUE(elf->memory()->Read(0, buffer.data(), 0x1000));
ASSERT_EQ(0, memcmp(buffer.data(), &ehdr, sizeof(ehdr)));
for (size_t i = sizeof(ehdr); i < 0x1000; i++) {
ASSERT_EQ(0, buffer[i]) << "Failed at byte " << i;
}
ASSERT_FALSE(elf->memory()->Read(0x1000, buffer.data(), 1));
}
// Verify that if the offset is non-zero and there is an elf at that
// offset, that only part of the file is used. Further verify that if the
// embedded elf is bigger than the initial map, the new object is larger
// than the original map size. Do this for a 32 bit elf and a 64 bit elf.
TEST_F(MapInfoGetElfTest, file_backed_non_zero_offset_partial_file_whole_elf32) {
MapInfo info{
.start = 0x5000, .end = 0x6000, .offset = 0x1000, .flags = PROT_READ, .name = elf_.path};
std::vector<uint8_t> buffer(0x4000);
memset(buffer.data(), 0, buffer.size());
Elf32_Ehdr ehdr;
TestInitEhdr<Elf32_Ehdr>(&ehdr, ELFCLASS32, EM_ARM);
ehdr.e_shoff = 0x2000;
ehdr.e_shentsize = sizeof(Elf32_Shdr) + 100;
ehdr.e_shnum = 4;
memcpy(&buffer[info.offset], &ehdr, sizeof(ehdr));
ASSERT_TRUE(android::base::WriteFully(elf_.fd, buffer.data(), buffer.size()));
std::unique_ptr<Elf> elf(info.GetElf(process_memory_, false));
ASSERT_TRUE(elf->valid());
ASSERT_TRUE(elf->memory() != nullptr);
ASSERT_EQ(0U, info.elf_offset);
// Verify the memory is a valid elf.
memset(buffer.data(), 0, buffer.size());
ASSERT_TRUE(elf->memory()->Read(0, buffer.data(), 0x1000));
ASSERT_EQ(0, memcmp(buffer.data(), &ehdr, sizeof(ehdr)));
// Read past the end of what would normally be the size of the map.
ASSERT_TRUE(elf->memory()->Read(0x1000, buffer.data(), 1));
}
TEST_F(MapInfoGetElfTest, file_backed_non_zero_offset_partial_file_whole_elf64) {
MapInfo info{
.start = 0x7000, .end = 0x8000, .offset = 0x1000, .flags = PROT_READ, .name = elf_.path};
std::vector<uint8_t> buffer(0x4000);
memset(buffer.data(), 0, buffer.size());
Elf64_Ehdr ehdr;
TestInitEhdr<Elf64_Ehdr>(&ehdr, ELFCLASS64, EM_AARCH64);
ehdr.e_shoff = 0x2000;
ehdr.e_shentsize = sizeof(Elf64_Shdr) + 100;
ehdr.e_shnum = 4;
memcpy(&buffer[info.offset], &ehdr, sizeof(ehdr));
ASSERT_TRUE(android::base::WriteFully(elf_.fd, buffer.data(), buffer.size()));
std::unique_ptr<Elf> elf(info.GetElf(process_memory_, false));
ASSERT_TRUE(elf->valid());
ASSERT_TRUE(elf->memory() != nullptr);
ASSERT_EQ(0U, info.elf_offset);
// Verify the memory is a valid elf.
memset(buffer.data(), 0, buffer.size());
ASSERT_TRUE(elf->memory()->Read(0, buffer.data(), 0x1000));
ASSERT_EQ(0, memcmp(buffer.data(), &ehdr, sizeof(ehdr)));
// Read past the end of what would normally be the size of the map.
ASSERT_TRUE(elf->memory()->Read(0x1000, buffer.data(), 1));
}
TEST_F(MapInfoGetElfTest, process_memory_not_read_only) {
MapInfo info{.start = 0x9000, .end = 0xa000, .offset = 0x1000, .flags = 0, .name = ""};
// Create valid elf data in process memory only.
Elf64_Ehdr ehdr;
TestInitEhdr<Elf64_Ehdr>(&ehdr, ELFCLASS64, EM_AARCH64);
ehdr.e_shoff = 0x2000;
ehdr.e_shentsize = sizeof(Elf64_Shdr) + 100;
ehdr.e_shnum = 4;
memory_->SetMemory(0x9000, &ehdr, sizeof(ehdr));
std::unique_ptr<Elf> elf(info.GetElf(process_memory_, false));
ASSERT_FALSE(elf->valid());
info.elf = nullptr;
info.flags = PROT_READ;
elf.reset(info.GetElf(process_memory_, false));
ASSERT_TRUE(elf->valid());
}
TEST_F(MapInfoGetElfTest, check_device_maps) {
MapInfo info{.start = 0x7000,
.end = 0x8000,
.offset = 0x1000,
.flags = PROT_READ | MAPS_FLAGS_DEVICE_MAP,
.name = "/dev/something"};
// Create valid elf data in process memory for this to verify that only
// the name is causing invalid elf data.
Elf64_Ehdr ehdr;
TestInitEhdr<Elf64_Ehdr>(&ehdr, ELFCLASS64, EM_X86_64);
ehdr.e_shoff = 0x2000;
ehdr.e_shentsize = sizeof(Elf64_Shdr) + 100;
ehdr.e_shnum = 4;
memory_->SetMemory(0x7000, &ehdr, sizeof(ehdr));
std::unique_ptr<Elf> elf(info.GetElf(process_memory_, false));
ASSERT_FALSE(elf->valid());
// Set the name to nothing to verify that it still fails.
info.elf = nullptr;
info.name = "";
elf.reset(info.GetElf(process_memory_, false));
ASSERT_FALSE(elf->valid());
// Change the flags and verify the elf is valid now.
info.elf = nullptr;
info.flags = PROT_READ;
elf.reset(info.GetElf(process_memory_, false));
ASSERT_TRUE(elf->valid());
}
} // namespace unwindstack
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