# # Copyright 2021 Espressif Systems (Shanghai) PTE LTD # # 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. # import hashlib import os from construct import (AlignedStruct, Bytes, Const, GreedyRange, Int16ul, Int32ul, Padding, Pointer, Sequence, Struct, this) # Following structs are based on spec # https://refspecs.linuxfoundation.org/elf/elf.pdf # and source code # IDF_PATH/components/espcoredump/include_core_dump/elf.h ElfIdentification = Struct( 'EI_MAG' / Const(b'\x7fELF'), 'EI_CLASS' / Const(b'\x01'), # ELFCLASS32 'EI_DATA' / Const(b'\x01'), # ELFDATA2LSB 'EI_VERSION' / Const(b'\x01'), # EV_CURRENT Padding(9), ) ElfHeader = Struct( 'e_ident' / ElfIdentification, 'e_type' / Int16ul, 'e_machine' / Int16ul, 'e_version' / Int32ul, 'e_entry' / Int32ul, 'e_phoff' / Int32ul, 'e_shoff' / Int32ul, 'e_flags' / Int32ul, 'e_ehsize' / Int16ul, 'e_phentsize' / Int16ul, 'e_phnum' / Int16ul, 'e_shentsize' / Int16ul, 'e_shnum' / Int16ul, 'e_shstrndx' / Int16ul, ) SectionHeader = Struct( 'sh_name' / Int32ul, 'sh_type' / Int32ul, 'sh_flags' / Int32ul, 'sh_addr' / Int32ul, 'sh_offset' / Int32ul, 'sh_size' / Int32ul, 'sh_link' / Int32ul, 'sh_info' / Int32ul, 'sh_addralign' / Int32ul, 'sh_entsize' / Int32ul, ) ProgramHeader = Struct( 'p_type' / Int32ul, 'p_offset' / Int32ul, 'p_vaddr' / Int32ul, 'p_paddr' / Int32ul, 'p_filesz' / Int32ul, 'p_memsz' / Int32ul, 'p_flags' / Int32ul, 'p_align' / Int32ul, ) ElfHeaderTables = Struct( 'elf_header' / ElfHeader, 'program_headers' / Pointer(this.elf_header.e_phoff, ProgramHeader[this.elf_header.e_phnum]), 'section_headers' / Pointer(this.elf_header.e_shoff, SectionHeader[this.elf_header.e_shnum]), ) NoteSection = AlignedStruct( 4, 'namesz' / Int32ul, 'descsz' / Int32ul, 'type' / Int32ul, 'name' / Bytes(this.namesz), 'desc' / Bytes(this.descsz), ) NoteSections = GreedyRange(NoteSection) class ElfFile(object): """ Elf class to a single elf file """ SHN_UNDEF = 0x00 SHT_PROGBITS = 0x01 SHT_STRTAB = 0x03 SHT_NOBITS = 0x08 PT_LOAD = 0x01 PT_NOTE = 0x04 ET_CORE = 0x04 EV_CURRENT = 0x01 def __init__(self, elf_path=None, e_type=None, e_machine=None): self.e_type = e_type self.e_machine = e_machine self._struct = None # construct Struct self._model = None # construct Container self._section_names = [] # type: list[str] self.sections = [] # type: list[ElfSection] self.load_segments = [] # type: list[ElfSegment] self.note_segments = [] # type: list[ElfNoteSegment] if elf_path and os.path.isfile(elf_path): self.read_elf(elf_path) def read_elf(self, elf_path): # type: (str) -> None """ Read elf file, also write to ``self.model``, ``self.program_headers``, ``self.section_headers`` :param elf_path: elf file path :return: None """ with open(elf_path, 'rb') as fr: elf_bytes = fr.read() header_tables = ElfHeaderTables.parse(elf_bytes) self.e_type = header_tables.elf_header.e_type self.e_machine = header_tables.elf_header.e_machine self._struct = self._generate_struct_from_headers(header_tables) self._model = self._struct.parse(elf_bytes) if 'string_table' in self._model: self._section_names = self._parse_string_table(self._model.string_table) self.load_segments = [ElfSegment(seg.ph.p_vaddr, seg.data, seg.ph.p_flags) for seg in self._model.load_segments] self.note_segments = [ElfNoteSegment(seg.ph.p_vaddr, seg.data, seg.ph.p_flags) for seg in self._model.note_segments] self.sections = [ElfSection(self._section_names[sec.sh.sh_name], sec.sh.sh_addr, sec.data, sec.sh.sh_flags) for sec in self._model.sections] @staticmethod def _parse_string_table(byte_str): # type: (bytes) -> dict name = '' index = 0 res = {} for i, c in enumerate(byte_str): if c in [0x00, '\x00']: # a workaround for python 2 bytes is actually string res[index] = name name = '' index = i + 1 continue if isinstance(c, int): name += chr(c) else: name += c return res def _generate_struct_from_headers(self, header_tables): """ Generate ``construct`` Struct for this file :param header_tables: contains elf_header, program_headers, section_headers :return: Struct of the whole file """ elf_header = header_tables.elf_header program_headers = header_tables.program_headers section_headers = header_tables.section_headers assert program_headers or section_headers string_table_sh = None load_segment_subcons = [] note_segment_subcons = [] # Here we point back to make segments know their program headers for i, ph in enumerate(program_headers): args = [ 'ph' / Pointer(elf_header.e_phoff + i * ProgramHeader.sizeof(), ProgramHeader), 'data' / Pointer(ph.p_offset, Bytes(ph.p_filesz)), ] if ph.p_vaddr == 0 and ph.p_type == self.PT_NOTE: args.append('note_secs' / Pointer(ph.p_offset, NoteSections)) note_segment_subcons.append(Struct(*args)) elif ph.p_vaddr != 0: load_segment_subcons.append(Struct(*args)) section_subcons = [] for i, sh in enumerate(section_headers): if sh.sh_type == self.SHT_STRTAB and i == elf_header.e_shstrndx: string_table_sh = sh elif sh.sh_addr != 0 and sh.sh_type == self.SHT_PROGBITS: section_subcons.append(Struct( 'sh' / Pointer(elf_header.e_shoff + i * SectionHeader.sizeof(), SectionHeader), 'data' / Pointer(sh.sh_offset, Bytes(sh.sh_size)), )) args = [ 'elf_header' / ElfHeader, 'load_segments' / Sequence(*load_segment_subcons), 'note_segments' / Sequence(*note_segment_subcons), 'sections' / Sequence(*section_subcons), ] if string_table_sh is not None: args.append('string_table' / Pointer(string_table_sh.sh_offset, Bytes(string_table_sh.sh_size))) return Struct(*args) @property def sha256(self): """ :return: SHA256 hash of the input ELF file """ sha256 = hashlib.sha256() sha256.update(self._struct.build(self._model)) return sha256.digest() class ElfSection(object): SHF_WRITE = 0x01 SHF_ALLOC = 0x02 SHF_EXECINSTR = 0x04 SHF_MASKPROC = 0xf0000000 def __init__(self, name, addr, data, flags): self.name = name self.addr = addr self.data = data self.flags = flags def attr_str(self): if self.flags & self.SHF_MASKPROC: return 'MS' res = 'R' res += 'W' if self.flags & self.SHF_WRITE else ' ' res += 'X' if self.flags & self.SHF_EXECINSTR else ' ' res += 'A' if self.flags & self.SHF_ALLOC else ' ' return res def __repr__(self): return '{:>32} [Addr] 0x{:>08X}, [Size] 0x{:>08X} {:>4}' \ .format(self.name, self.addr, len(self.data), self.attr_str()) class ElfSegment(object): PF_X = 0x01 PF_W = 0x02 PF_R = 0x04 def __init__(self, addr, data, flags): self.addr = addr self.data = data self.flags = flags self.type = ElfFile.PT_LOAD def attr_str(self): res = '' res += 'R' if self.flags & self.PF_R else ' ' res += 'W' if self.flags & self.PF_W else ' ' res += 'E' if self.flags & self.PF_X else ' ' return res @staticmethod def _type_str(): return 'LOAD' def __repr__(self): return '{:>8} Addr 0x{:>08X}, Size 0x{:>08X} Flags {:4}' \ .format(self._type_str(), self.addr, len(self.data), self.attr_str()) class ElfNoteSegment(ElfSegment): def __init__(self, addr, data, flags): super(ElfNoteSegment, self).__init__(addr, data, flags) self.type = ElfFile.PT_NOTE self.note_secs = NoteSections.parse(self.data) @staticmethod def _type_str(): return 'NOTE' TASK_STATUS_CORRECT = 0x00 TASK_STATUS_TCB_CORRUPTED = 0x01 TASK_STATUS_STACK_CORRUPTED = 0x02 EspTaskStatus = Struct( 'task_index' / Int32ul, 'task_flags' / Int32ul, 'task_tcb_addr' / Int32ul, 'task_stack_start' / Int32ul, 'task_stack_len' / Int32ul, 'task_name' / Bytes(16), ) class ESPCoreDumpElfFile(ElfFile): PT_INFO = 8266 PT_TASK_INFO = 678 PT_EXTRA_INFO = 677 CURR_TASK_MARKER = 0xdeadbeef # ELF file machine type EM_XTENSA = 0x5E def __init__(self, elf_path=None, e_type=None, e_machine=None): _e_type = e_type or self.ET_CORE _e_machine = e_machine or self.EM_XTENSA super(ESPCoreDumpElfFile, self).__init__(elf_path, _e_type, _e_machine) def add_segment(self, addr, data, seg_type, flags): if seg_type != self.PT_NOTE: self.load_segments.append(ElfSegment(addr, data, flags)) else: self.note_segments.append(ElfNoteSegment(addr, data, flags)) def dump(self, output_path): # type: (str) -> None """ Dump self.model into file :param output_path: output file path :return: None """ res = b'' res += ElfHeader.build({ 'e_type': self.e_type, 'e_machine': self.e_machine, 'e_version': self.EV_CURRENT, 'e_entry': 0, 'e_phoff': ElfHeader.sizeof(), 'e_shoff': 0, 'e_flags': 0, 'e_ehsize': ElfHeader.sizeof(), 'e_phentsize': ProgramHeader.sizeof(), 'e_phnum': len(self.load_segments) + len(self.note_segments), 'e_shentsize': 0, 'e_shnum': 0, 'e_shstrndx': self.SHN_UNDEF, }) offset = ElfHeader.sizeof() + (len(self.load_segments) + len(self.note_segments)) * ProgramHeader.sizeof() _segments = self.load_segments + self.note_segments for seg in _segments: res += ProgramHeader.build({ 'p_type': seg.type, 'p_offset': offset, 'p_vaddr': seg.addr, 'p_paddr': seg.addr, 'p_filesz': len(seg.data), 'p_memsz': len(seg.data), 'p_flags': seg.flags, 'p_align': 0, }) offset += len(seg.data) for seg in _segments: res += seg.data with open(output_path, 'wb') as fw: fw.write(res)