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/*
* Copyright (C) 2012 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#pragma once
/* Declarations related to the ELF program header table and segments.
*
* The design goal is to provide an API that is as close as possible
* to the ELF spec, and does not depend on linker-specific data
* structures (e.g. the exact layout of struct soinfo).
*/
#include "linker.h"
#include "linker_mapped_file_fragment.h"
#include "linker_note_gnu_property.h"
class ElfReader {
public:
ElfReader();
[[nodiscard]] bool Read(const char* name, int fd, off64_t file_offset, off64_t file_size);
[[nodiscard]] bool Load(address_space_params* address_space);
const char* name() const { return name_.c_str(); }
size_t phdr_count() const { return phdr_num_; }
ElfW(Addr) load_start() const { return reinterpret_cast<ElfW(Addr)>(load_start_); }
size_t load_size() const { return load_size_; }
ElfW(Addr) gap_start() const { return reinterpret_cast<ElfW(Addr)>(gap_start_); }
size_t gap_size() const { return gap_size_; }
ElfW(Addr) load_bias() const { return load_bias_; }
const ElfW(Phdr)* loaded_phdr() const { return loaded_phdr_; }
const ElfW(Dyn)* dynamic() const { return dynamic_; }
const char* get_string(ElfW(Word) index) const;
bool is_mapped_by_caller() const { return mapped_by_caller_; }
ElfW(Addr) entry_point() const { return header_.e_entry + load_bias_; }
bool should_pad_segments() const { return should_pad_segments_; }
private:
[[nodiscard]] bool ReadElfHeader();
[[nodiscard]] bool VerifyElfHeader();
[[nodiscard]] bool ReadProgramHeaders();
[[nodiscard]] bool ReadSectionHeaders();
[[nodiscard]] bool ReadDynamicSection();
[[nodiscard]] bool ReadPadSegmentNote();
[[nodiscard]] bool ReserveAddressSpace(address_space_params* address_space);
[[nodiscard]] bool LoadSegments();
[[nodiscard]] bool FindPhdr();
[[nodiscard]] bool FindGnuPropertySection();
[[nodiscard]] bool CheckPhdr(ElfW(Addr));
[[nodiscard]] bool CheckFileRange(ElfW(Addr) offset, size_t size, size_t alignment);
bool did_read_;
bool did_load_;
std::string name_;
int fd_;
off64_t file_offset_;
off64_t file_size_;
ElfW(Ehdr) header_;
size_t phdr_num_;
MappedFileFragment phdr_fragment_;
const ElfW(Phdr)* phdr_table_;
MappedFileFragment shdr_fragment_;
const ElfW(Shdr)* shdr_table_;
size_t shdr_num_;
MappedFileFragment dynamic_fragment_;
const ElfW(Dyn)* dynamic_;
MappedFileFragment strtab_fragment_;
const char* strtab_;
size_t strtab_size_;
// First page of reserved address space.
void* load_start_;
// Size in bytes of reserved address space.
size_t load_size_;
// First page of inaccessible gap mapping reserved for this DSO.
void* gap_start_;
// Size in bytes of the gap mapping.
size_t gap_size_;
// Load bias.
ElfW(Addr) load_bias_;
// Loaded phdr.
const ElfW(Phdr)* loaded_phdr_;
// Is map owned by the caller
bool mapped_by_caller_;
// Pad gaps between segments when memory mapping?
bool should_pad_segments_ = false;
// Only used by AArch64 at the moment.
GnuPropertySection note_gnu_property_ __unused;
};
size_t phdr_table_get_load_size(const ElfW(Phdr)* phdr_table, size_t phdr_count,
ElfW(Addr)* min_vaddr = nullptr, ElfW(Addr)* max_vaddr = nullptr);
size_t phdr_table_get_maximum_alignment(const ElfW(Phdr)* phdr_table, size_t phdr_count);
int phdr_table_protect_segments(const ElfW(Phdr)* phdr_table, size_t phdr_count,
ElfW(Addr) load_bias, bool should_pad_segments,
const GnuPropertySection* prop = nullptr);
int phdr_table_unprotect_segments(const ElfW(Phdr)* phdr_table, size_t phdr_count,
ElfW(Addr) load_bias, bool should_pad_segments);
int phdr_table_protect_gnu_relro(const ElfW(Phdr)* phdr_table, size_t phdr_count,
ElfW(Addr) load_bias, bool should_pad_segments);
int phdr_table_serialize_gnu_relro(const ElfW(Phdr)* phdr_table, size_t phdr_count,
ElfW(Addr) load_bias, int fd, size_t* file_offset);
int phdr_table_map_gnu_relro(const ElfW(Phdr)* phdr_table, size_t phdr_count,
ElfW(Addr) load_bias, int fd, size_t* file_offset);
#if defined(__arm__)
int phdr_table_get_arm_exidx(const ElfW(Phdr)* phdr_table, size_t phdr_count, ElfW(Addr) load_bias,
ElfW(Addr)** arm_exidx, size_t* arm_exidix_count);
#endif
void phdr_table_get_dynamic_section(const ElfW(Phdr)* phdr_table, size_t phdr_count,
ElfW(Addr) load_bias, ElfW(Dyn)** dynamic,
ElfW(Word)* dynamic_flags);
const char* phdr_table_get_interpreter_name(const ElfW(Phdr)* phdr_table, size_t phdr_count,
ElfW(Addr) load_bias);
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