diff options
| -rw-r--r-- | Makefile.am | 3 | ||||
| -rw-r--r-- | contrib/devtools/pixie.py | 323 |
2 files changed, 1 insertions, 325 deletions
diff --git a/Makefile.am b/Makefile.am index a495ad6209..af63cf0cbb 100644 --- a/Makefile.am +++ b/Makefile.am @@ -58,8 +58,7 @@ DIST_SHARE = \ BIN_CHECKS=$(top_srcdir)/contrib/devtools/symbol-check.py \ $(top_srcdir)/contrib/devtools/security-check.py \ - $(top_srcdir)/contrib/devtools/utils.py \ - $(top_srcdir)/contrib/devtools/pixie.py + $(top_srcdir)/contrib/devtools/utils.py WINDOWS_PACKAGING = $(top_srcdir)/share/pixmaps/bitcoin.ico \ $(top_srcdir)/share/pixmaps/nsis-header.bmp \ diff --git a/contrib/devtools/pixie.py b/contrib/devtools/pixie.py deleted file mode 100644 index 64660968ad..0000000000 --- a/contrib/devtools/pixie.py +++ /dev/null @@ -1,323 +0,0 @@ -#!/usr/bin/env python3 -# Copyright (c) 2020 Wladimir J. van der Laan -# Distributed under the MIT software license, see the accompanying -# file COPYING or http://www.opensource.org/licenses/mit-license.php. -''' -Compact, self-contained ELF implementation for bitcoin-core security checks. -''' -import struct -import types -from typing import Dict, List, Optional, Union, Tuple - -# you can find all these values in elf.h -EI_NIDENT = 16 - -# Byte indices in e_ident -EI_CLASS = 4 # ELFCLASSxx -EI_DATA = 5 # ELFDATAxxxx - -ELFCLASS32 = 1 # 32-bit -ELFCLASS64 = 2 # 64-bit - -ELFDATA2LSB = 1 # little endian -ELFDATA2MSB = 2 # big endian - -# relevant values for e_machine -EM_386 = 3 -EM_PPC64 = 21 -EM_ARM = 40 -EM_AARCH64 = 183 -EM_X86_64 = 62 -EM_RISCV = 243 - -# relevant values for e_type -ET_DYN = 3 - -# relevant values for sh_type -SHT_PROGBITS = 1 -SHT_STRTAB = 3 -SHT_DYNAMIC = 6 -SHT_DYNSYM = 11 -SHT_GNU_verneed = 0x6ffffffe -SHT_GNU_versym = 0x6fffffff - -# relevant values for p_type -PT_LOAD = 1 -PT_GNU_STACK = 0x6474e551 -PT_GNU_RELRO = 0x6474e552 - -# relevant values for p_flags -PF_X = (1 << 0) -PF_W = (1 << 1) -PF_R = (1 << 2) - -# relevant values for d_tag -DT_NEEDED = 1 -DT_FLAGS = 30 - -# relevant values of `d_un.d_val' in the DT_FLAGS entry -DF_BIND_NOW = 0x00000008 - -# relevant d_tags with string payload -STRING_TAGS = {DT_NEEDED} - -# rrlevant values for ST_BIND subfield of st_info (symbol binding) -STB_LOCAL = 0 - -class ELFRecord(types.SimpleNamespace): - '''Unified parsing for ELF records.''' - def __init__(self, data: bytes, offset: int, eh: 'ELFHeader', total_size: Optional[int]) -> None: - hdr_struct = self.STRUCT[eh.ei_class][0][eh.ei_data] - if total_size is not None and hdr_struct.size > total_size: - raise ValueError(f'{self.__class__.__name__} header size too small ({total_size} < {hdr_struct.size})') - for field, value in zip(self.STRUCT[eh.ei_class][1], hdr_struct.unpack(data[offset:offset + hdr_struct.size])): - setattr(self, field, value) - -def BiStruct(chars: str) -> Dict[int, struct.Struct]: - '''Compile a struct parser for both endians.''' - return { - ELFDATA2LSB: struct.Struct('<' + chars), - ELFDATA2MSB: struct.Struct('>' + chars), - } - -class ELFHeader(ELFRecord): - FIELDS = ['e_type', 'e_machine', 'e_version', 'e_entry', 'e_phoff', 'e_shoff', 'e_flags', 'e_ehsize', 'e_phentsize', 'e_phnum', 'e_shentsize', 'e_shnum', 'e_shstrndx'] - STRUCT = { - ELFCLASS32: (BiStruct('HHIIIIIHHHHHH'), FIELDS), - ELFCLASS64: (BiStruct('HHIQQQIHHHHHH'), FIELDS), - } - - def __init__(self, data: bytes, offset: int) -> None: - self.e_ident = data[offset:offset + EI_NIDENT] - if self.e_ident[0:4] != b'\x7fELF': - raise ValueError('invalid ELF magic') - self.ei_class = self.e_ident[EI_CLASS] - self.ei_data = self.e_ident[EI_DATA] - - super().__init__(data, offset + EI_NIDENT, self, None) - - def __repr__(self) -> str: - return f'Header(e_ident={self.e_ident!r}, e_type={self.e_type}, e_machine={self.e_machine}, e_version={self.e_version}, e_entry={self.e_entry}, e_phoff={self.e_phoff}, e_shoff={self.e_shoff}, e_flags={self.e_flags}, e_ehsize={self.e_ehsize}, e_phentsize={self.e_phentsize}, e_phnum={self.e_phnum}, e_shentsize={self.e_shentsize}, e_shnum={self.e_shnum}, e_shstrndx={self.e_shstrndx})' - -class Section(ELFRecord): - name: Optional[bytes] = None - FIELDS = ['sh_name', 'sh_type', 'sh_flags', 'sh_addr', 'sh_offset', 'sh_size', 'sh_link', 'sh_info', 'sh_addralign', 'sh_entsize'] - STRUCT = { - ELFCLASS32: (BiStruct('IIIIIIIIII'), FIELDS), - ELFCLASS64: (BiStruct('IIQQQQIIQQ'), FIELDS), - } - - def __init__(self, data: bytes, offset: int, eh: ELFHeader) -> None: - super().__init__(data, offset, eh, eh.e_shentsize) - self._data = data - - def __repr__(self) -> str: - return f'Section(sh_name={self.sh_name}({self.name!r}), sh_type=0x{self.sh_type:x}, sh_flags={self.sh_flags}, sh_addr=0x{self.sh_addr:x}, sh_offset=0x{self.sh_offset:x}, sh_size={self.sh_size}, sh_link={self.sh_link}, sh_info={self.sh_info}, sh_addralign={self.sh_addralign}, sh_entsize={self.sh_entsize})' - - def contents(self) -> bytes: - '''Return section contents.''' - return self._data[self.sh_offset:self.sh_offset + self.sh_size] - -class ProgramHeader(ELFRecord): - STRUCT = { - # different ELF classes have the same fields, but in a different order to optimize space versus alignment - ELFCLASS32: (BiStruct('IIIIIIII'), ['p_type', 'p_offset', 'p_vaddr', 'p_paddr', 'p_filesz', 'p_memsz', 'p_flags', 'p_align']), - ELFCLASS64: (BiStruct('IIQQQQQQ'), ['p_type', 'p_flags', 'p_offset', 'p_vaddr', 'p_paddr', 'p_filesz', 'p_memsz', 'p_align']), - } - - def __init__(self, data: bytes, offset: int, eh: ELFHeader) -> None: - super().__init__(data, offset, eh, eh.e_phentsize) - - def __repr__(self) -> str: - return f'ProgramHeader(p_type={self.p_type}, p_offset={self.p_offset}, p_vaddr={self.p_vaddr}, p_paddr={self.p_paddr}, p_filesz={self.p_filesz}, p_memsz={self.p_memsz}, p_flags={self.p_flags}, p_align={self.p_align})' - -class Symbol(ELFRecord): - STRUCT = { - # different ELF classes have the same fields, but in a different order to optimize space versus alignment - ELFCLASS32: (BiStruct('IIIBBH'), ['st_name', 'st_value', 'st_size', 'st_info', 'st_other', 'st_shndx']), - ELFCLASS64: (BiStruct('IBBHQQ'), ['st_name', 'st_info', 'st_other', 'st_shndx', 'st_value', 'st_size']), - } - - def __init__(self, data: bytes, offset: int, eh: ELFHeader, symtab: Section, strings: bytes, version: Optional[bytes]) -> None: - super().__init__(data, offset, eh, symtab.sh_entsize) - self.name = _lookup_string(strings, self.st_name) - self.version = version - - def __repr__(self) -> str: - return f'Symbol(st_name={self.st_name}({self.name!r}), st_value={self.st_value}, st_size={self.st_size}, st_info={self.st_info}, st_other={self.st_other}, st_shndx={self.st_shndx}, version={self.version!r})' - - @property - def is_import(self) -> bool: - '''Returns whether the symbol is an imported symbol.''' - return self.st_bind != STB_LOCAL and self.st_shndx == 0 - - @property - def is_export(self) -> bool: - '''Returns whether the symbol is an exported symbol.''' - return self.st_bind != STB_LOCAL and self.st_shndx != 0 - - @property - def st_bind(self) -> int: - '''Returns STB_*.''' - return self.st_info >> 4 - -class Verneed(ELFRecord): - DEF = (BiStruct('HHIII'), ['vn_version', 'vn_cnt', 'vn_file', 'vn_aux', 'vn_next']) - STRUCT = { ELFCLASS32: DEF, ELFCLASS64: DEF } - - def __init__(self, data: bytes, offset: int, eh: ELFHeader) -> None: - super().__init__(data, offset, eh, None) - - def __repr__(self) -> str: - return f'Verneed(vn_version={self.vn_version}, vn_cnt={self.vn_cnt}, vn_file={self.vn_file}, vn_aux={self.vn_aux}, vn_next={self.vn_next})' - -class Vernaux(ELFRecord): - DEF = (BiStruct('IHHII'), ['vna_hash', 'vna_flags', 'vna_other', 'vna_name', 'vna_next']) - STRUCT = { ELFCLASS32: DEF, ELFCLASS64: DEF } - - def __init__(self, data: bytes, offset: int, eh: ELFHeader, strings: bytes) -> None: - super().__init__(data, offset, eh, None) - self.name = _lookup_string(strings, self.vna_name) - - def __repr__(self) -> str: - return f'Veraux(vna_hash={self.vna_hash}, vna_flags={self.vna_flags}, vna_other={self.vna_other}, vna_name={self.vna_name}({self.name!r}), vna_next={self.vna_next})' - -class DynTag(ELFRecord): - STRUCT = { - ELFCLASS32: (BiStruct('II'), ['d_tag', 'd_val']), - ELFCLASS64: (BiStruct('QQ'), ['d_tag', 'd_val']), - } - - def __init__(self, data: bytes, offset: int, eh: ELFHeader, section: Section) -> None: - super().__init__(data, offset, eh, section.sh_entsize) - - def __repr__(self) -> str: - return f'DynTag(d_tag={self.d_tag}, d_val={self.d_val})' - -def _lookup_string(data: bytes, index: int) -> bytes: - '''Look up string by offset in ELF string table.''' - endx = data.find(b'\x00', index) - assert endx != -1 - return data[index:endx] - -VERSYM_S = BiStruct('H') # .gnu_version section has a single 16-bit integer per symbol in the linked section -def _parse_symbol_table(section: Section, strings: bytes, eh: ELFHeader, versym: bytes, verneed: Dict[int, bytes]) -> List[Symbol]: - '''Parse symbol table, return a list of symbols.''' - data = section.contents() - symbols = [] - versym_iter = (verneed.get(v[0]) for v in VERSYM_S[eh.ei_data].iter_unpack(versym)) - for ofs, version in zip(range(0, len(data), section.sh_entsize), versym_iter): - symbols.append(Symbol(data, ofs, eh, section, strings, version)) - return symbols - -def _parse_verneed(section: Section, strings: bytes, eh: ELFHeader) -> Dict[int, bytes]: - '''Parse .gnu.version_r section, return a dictionary of {versym: 'GLIBC_...'}.''' - data = section.contents() - ofs = 0 - result = {} - while True: - verneed = Verneed(data, ofs, eh) - aofs = ofs + verneed.vn_aux - while True: - vernaux = Vernaux(data, aofs, eh, strings) - result[vernaux.vna_other] = vernaux.name - if not vernaux.vna_next: - break - aofs += vernaux.vna_next - - if not verneed.vn_next: - break - ofs += verneed.vn_next - - return result - -def _parse_dyn_tags(section: Section, strings: bytes, eh: ELFHeader) -> List[Tuple[int, Union[bytes, int]]]: - '''Parse dynamic tags. Return array of tuples.''' - data = section.contents() - ofs = 0 - result = [] - for ofs in range(0, len(data), section.sh_entsize): - tag = DynTag(data, ofs, eh, section) - val = _lookup_string(strings, tag.d_val) if tag.d_tag in STRING_TAGS else tag.d_val - result.append((tag.d_tag, val)) - - return result - -class ELFFile: - sections: List[Section] - program_headers: List[ProgramHeader] - dyn_symbols: List[Symbol] - dyn_tags: List[Tuple[int, Union[bytes, int]]] - - def __init__(self, data: bytes) -> None: - self.data = data - self.hdr = ELFHeader(self.data, 0) - self._load_sections() - self._load_program_headers() - self._load_dyn_symbols() - self._load_dyn_tags() - self._section_to_segment_mapping() - - def _load_sections(self) -> None: - self.sections = [] - for idx in range(self.hdr.e_shnum): - offset = self.hdr.e_shoff + idx * self.hdr.e_shentsize - self.sections.append(Section(self.data, offset, self.hdr)) - - shstr = self.sections[self.hdr.e_shstrndx].contents() - for section in self.sections: - section.name = _lookup_string(shstr, section.sh_name) - - def _load_program_headers(self) -> None: - self.program_headers = [] - for idx in range(self.hdr.e_phnum): - offset = self.hdr.e_phoff + idx * self.hdr.e_phentsize - self.program_headers.append(ProgramHeader(self.data, offset, self.hdr)) - - def _load_dyn_symbols(self) -> None: - # first, load 'verneed' section - verneed = None - for section in self.sections: - if section.sh_type == SHT_GNU_verneed: - strtab = self.sections[section.sh_link].contents() # associated string table - assert verneed is None # only one section of this kind please - verneed = _parse_verneed(section, strtab, self.hdr) - assert verneed is not None - - # then, correlate GNU versym sections with dynamic symbol sections - versym = {} - for section in self.sections: - if section.sh_type == SHT_GNU_versym: - versym[section.sh_link] = section - - # finally, load dynsym sections - self.dyn_symbols = [] - for idx, section in enumerate(self.sections): - if section.sh_type == SHT_DYNSYM: # find dynamic symbol tables - strtab_data = self.sections[section.sh_link].contents() # associated string table - versym_data = versym[idx].contents() # associated symbol version table - self.dyn_symbols += _parse_symbol_table(section, strtab_data, self.hdr, versym_data, verneed) - - def _load_dyn_tags(self) -> None: - self.dyn_tags = [] - for idx, section in enumerate(self.sections): - if section.sh_type == SHT_DYNAMIC: # find dynamic tag tables - strtab = self.sections[section.sh_link].contents() # associated string table - self.dyn_tags += _parse_dyn_tags(section, strtab, self.hdr) - - def _section_to_segment_mapping(self) -> None: - for ph in self.program_headers: - ph.sections = [] - for section in self.sections: - if ph.p_vaddr <= section.sh_addr < (ph.p_vaddr + ph.p_memsz): - ph.sections.append(section) - - def query_dyn_tags(self, tag_in: int) -> List[Union[int, bytes]]: - '''Return the values of all dyn tags with the specified tag.''' - return [val for (tag, val) in self.dyn_tags if tag == tag_in] - - -def load(filename: str) -> ELFFile: - with open(filename, 'rb') as f: - data = f.read() - return ELFFile(data) |