# Copyright 2017 Reswitched Team # # Permission to use, copy, modify, and/or distribute this software for any purpose with or # without fee is hereby granted, provided that the above copyright notice and this permission # notice appear in all copies. # # THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS # SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL # THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY # DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF # CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE # OR PERFORMANCE OF THIS SOFTWARE. # nxo64.py: IDA loader (and library for reading nso/nro files) import gzip, math, os, re, struct, sys from struct import unpack as up, pack as pk from io import BytesIO from cStringIO import StringIO (DT_NULL, DT_NEEDED, DT_PLTRELSZ, DT_PLTGOT, DT_HASH, DT_STRTAB, DT_SYMTAB, DT_RELA, DT_RELASZ, DT_RELAENT, DT_STRSZ, DT_SYMENT, DT_INIT, DT_FINI, DT_SONAME, DT_RPATH, DT_SYMBOLIC, DT_REL, DT_RELSZ, DT_RELENT, DT_PLTREL, DT_DEBUG, DT_TEXTREL, DT_JMPREL, DT_BIND_NOW, DT_INIT_ARRAY, DT_FINI_ARRAY, DT_INIT_ARRAYSZ, DT_FINI_ARRAYSZ, DT_RUNPATH, DT_FLAGS) = xrange(31) DT_GNU_HASH = 0x6ffffef5 DT_VERSYM = 0x6ffffff0 DT_RELACOUNT = 0x6ffffff9 DT_RELCOUNT = 0x6ffffffa DT_FLAGS_1 = 0x6ffffffb DT_VERDEF = 0x6ffffffc DT_VERDEFNUM = 0x6ffffffd STT_NOTYPE = 0 STT_OBJECT = 1 STT_FUNC = 2 STT_SECTION = 3 STB_LOCAL = 0 STB_GLOBAL = 1 STB_WEAK = 2 R_ARM_ABS32 = 2 R_ARM_TLS_DESC = 13 R_ARM_GLOB_DAT = 21 R_ARM_JUMP_SLOT = 22 R_ARM_RELATIVE = 23 R_AARCH64_ABS64 = 257 R_AARCH64_GLOB_DAT = 1025 R_AARCH64_JUMP_SLOT = 1026 R_AARCH64_RELATIVE = 1027 R_AARCH64_TLSDESC = 1031 MULTIPLE_DTS = set([DT_NEEDED]) class Range(object): def __init__(self, start, size): self.start = start self.size = size self.end = start+size self._inclend = start+size-1 def overlaps(self, other): return self.start <= other._inclend and other.start <= self._inclend def includes(self, other): return other.start >= self.start and other._inclend <= self._inclend def __repr__(self): return 'Range(0x%X -> 0x%X)' % (self.start, self.end) class Segment(object): def __init__(self, r, name, kind): self.range = r self.name = name self.kind = kind self.sections = [] def add_section(self, s): for i in self.sections: assert not i.range.overlaps(s.range), '%r overlaps %r' % (s, i) self.sections.append(s) class Section(object): def __init__(self, r, name): self.range = r self.name = name def __repr__(self): return 'Section(%r, %r)' % (self.range, self.name) def suffixed_name(name, suffix): if suffix == 0: return name return '%s.%d' % (name, suffix) class SegmentBuilder(object): def __init__(self): self.segments = [] def add_segment(self, start, size, name, kind): r = Range(start, size) for i in self.segments: assert not r.overlaps(i.range) self.segments.append(Segment(r, name, kind)) def add_section(self, name, start, end=None, size=None): assert end is None or size is None if size is None: size = end-start assert size > 0 r = Range(start, size) for i in self.segments: if i.range.includes(r): i.add_section(Section(r, name)) return assert False, "no containing segment for %r" % (name,) def flatten(self): self.segments.sort(key=lambda s: s.range.start) parts = [] for segment in self.segments: suffix = 0 segment.sections.sort(key=lambda s: s.range.start) pos = segment.range.start for section in segment.sections: if pos < section.range.start: parts.append((pos, section.range.start, suffixed_name(segment.name, suffix), segment.kind)) suffix += 1 pos = section.range.start parts.append((section.range.start, section.range.end, section.name, segment.kind)) pos = section.range.end if pos < segment.range.end: parts.append((pos, segment.range.end, suffixed_name(segment.name, suffix), segment.kind)) suffix += 1 pos = segment.range.end return parts class ElfSym(object): def __init__(self, name, info, other, shndx, value, size): self.name = name self.shndx = shndx self.value = value self.size = size self.vis = other & 3 self.type = info & 0xF self.bind = info >> 4 def __repr__(self): return 'Sym(name=%r, shndx=0x%X, value=0x%X, size=0x%X, vis=%r, type=%r, bind=%r)' % ( self.name, self.shndx, self.value, self.size, self.vis, self.type, self.bind) class Kernel50(object): def __init__(self, fileobj): f = BinFile(fileobj) b = 0x80060000 self.textoff = 0 self.textsize = 0x800BD000 - b self.rodataoff = 0x800BD000 - b self.rodatasize = 0x800D0000 - 0x800BD000 self.dataoff = 0x800D0000 - b self.datasize = 0x800D1A40 - 0x800D0000#0x800E4000 - 0x800D0000 flatsize = self.dataoff + self.datasize self.binfile = f self.dynamicoff = 0x800D1378 - b self.bssoff = 0x800D1A40 - b self.bssend = 0x800E4000 - b self.datasize = self.bssoff - self.dataoff self.bsssize = self.bssend - self.bssoff self.segment_builder = builder = SegmentBuilder() for off,sz,name,kind in [ (self.textoff, self.textsize, ".text", "CODE"), (self.rodataoff, self.rodatasize, ".rodata", "CONST"), (self.dataoff, self.datasize, ".data", "DATA"), (self.bssoff, self.bsssize, ".bss", "BSS"), ]: builder.add_segment(off, sz, name, kind) # read dynamic self.armv7 = False#(f.read_from('Q', self.dynamicoff) > 0xFFFFFFFF or f.read_from('Q', self.dynamicoff+0x10) > 0xFFFFFFFF) self.offsize = 4 if self.armv7 else 8 f.seek(self.dynamicoff) self.dynamic = dynamic = {} for i in MULTIPLE_DTS: dynamic[i] = [] for i in xrange((flatsize - self.dynamicoff) / 0x10): tag, val = f.read('II' if self.armv7 else 'QQ') if tag == DT_NULL: break if tag in MULTIPLE_DTS: dynamic[tag].append(val) else: dynamic[tag] = val dynamicend = f.tell() builder.add_section('.dynamic', self.dynamicoff, dynamicend) # read .dynstr if DT_STRTAB in dynamic and DT_STRSZ in dynamic: f.seek(dynamic[DT_STRTAB]) self.dynstr = f.read(dynamic[DT_STRSZ]) else: self.dynstr = '\0' print 'warning: no dynstr' for startkey, szkey, name in [ (DT_STRTAB, DT_STRSZ, '.dynstr'), (DT_INIT_ARRAY, DT_INIT_ARRAYSZ, '.init_array'), (DT_FINI_ARRAY, DT_FINI_ARRAYSZ, '.fini_array'), (DT_RELA, DT_RELASZ, '.rela.dyn'), (DT_REL, DT_RELSZ, '.rel.dyn'), (DT_JMPREL, DT_PLTRELSZ, ('.rel.plt' if self.armv7 else '.rela.plt')), ]: if startkey in dynamic and szkey in dynamic: builder.add_section(name, dynamic[startkey], size=dynamic[szkey]) self.needed = [self.get_dynstr(i) for i in self.dynamic[DT_NEEDED]] # load .dynsym self.symbols = symbols = [] f.seek(dynamic[DT_SYMTAB]) while True: if dynamic[DT_SYMTAB] < dynamic[DT_STRTAB] and f.tell() >= dynamic[DT_STRTAB]: break if self.armv7: st_name, st_value, st_size, st_info, st_other, st_shndx = f.read('IIIBBH') else: st_name, st_info, st_other, st_shndx, st_value, st_size = f.read('IBBHQQ') if st_name > len(self.dynstr): break symbols.append(ElfSym(self.get_dynstr(st_name), st_info, st_other, st_shndx, st_value, st_size)) builder.add_section('.dynsym', dynamic[DT_SYMTAB], end=f.tell()) self.plt_entries = [] self.relocations = [] locations = set() if DT_REL in dynamic: locations |= self.process_relocations(f, symbols, dynamic[DT_REL], dynamic[DT_RELSZ]) if DT_RELA in dynamic: locations |= self.process_relocations(f, symbols, dynamic[DT_RELA], dynamic[DT_RELASZ]) if DT_JMPREL in dynamic: # Note: 5.0 kernel doesn't have it pltlocations = self.process_relocations(f, symbols, dynamic[DT_JMPREL], dynamic[DT_PLTRELSZ]) locations |= pltlocations plt_got_start = min(pltlocations) plt_got_end = max(pltlocations) + self.offsize if DT_PLTGOT in dynamic: builder.add_section('.got.plt', dynamic[DT_PLTGOT], end=plt_got_end) if not self.armv7: f.seek(0) text = f.read(self.textsize) last = 12 while True: pos = text.find(struct.pack('<I', 0xD61F0220), last) if pos == -1: break last = pos+1 if (pos % 4) != 0: continue off = pos - 12 a, b, c, d = struct.unpack_from('<IIII', text, off) if d == 0xD61F0220 and (a & 0x9f00001f) == 0x90000010 and (b & 0xffe003ff) == 0xf9400211: base = off & ~0xFFF immhi = (a >> 5) & 0x7ffff immlo = (a >> 29) & 3 paddr = base + ((immlo << 12) | (immhi << 14)) poff = ((b >> 10) & 0xfff) << 3 target = paddr + poff if plt_got_start <= target < plt_got_end: self.plt_entries.append((off, target)) builder.add_section('.plt', min(self.plt_entries)[0], end=max(self.plt_entries)[0] + 0x10) # try to find the ".got" which should follow the ".got.plt" good = False got_end = plt_got_end + self.offsize while got_end in locations and (DT_INIT_ARRAY not in dynamic or got_end < dynamic[DT_INIT_ARRAY]): good = True got_end += self.offsize if good: builder.add_section('.got', plt_got_end, end=got_end) else: # .got is between .dynamic and .init_array on 5.0 builder.add_section('.got', dynamicend, dynamic[DT_INIT_ARRAY]) self.sections = [] for start, end, name, kind in builder.flatten(): self.sections.append((start, end, name, kind)) def process_relocations(self, f, symbols, offset, size): locations = set() f.seek(offset) relocsize = 8 if self.armv7 else 0x18 for i in xrange(size / relocsize): # NOTE: currently assumes all armv7 relocs have no addends, # and all 64-bit ones do. if self.armv7: offset, info = f.read('II') addend = None r_type = info & 0xff r_sym = info >> 8 else: offset, info, addend = f.read('QQq') r_type = info & 0xffffffff r_sym = info >> 32 sym = symbols[r_sym] if r_sym != 0 else None if r_type != R_AARCH64_TLSDESC and r_type != R_ARM_TLS_DESC: locations.add(offset) self.relocations.append((offset, r_type, sym, addend)) return locations def get_dynstr(self, o): return self.dynstr[o:self.dynstr.index('\0', o)] class NxoException(Exception): pass def load_nxo(fileobj): fileobj.seek(0) return Kernel50(fileobj) try: import idaapi import idc except ImportError: pass else: # IDA specific code def accept_file(li, n): if not isinstance(n, (int,long)) or n == 0: li.seek(0) if li.read(8) == '\xDFO\x03\xD5AB8\xD5': return '5.0 KNX' return 0 def ida_make_offset(f, ea): if f.armv7: idc.MakeDword(ea) else: idc.MakeQword(ea) idc.OpOff(ea, 0, 0) def find_bl_targets(text_start, text_end): targets = set() for pc in range(text_start, text_end, 4): d = Dword(pc) if (d & 0xfc000000) == 0x94000000: imm = d & 0x3ffffff if imm & 0x2000000: imm |= ~0x1ffffff if 0 <= imm <= 2: continue target = pc + imm * 4 if target >= text_start and target < text_end: targets.add(target) return targets def load_file(li, neflags, format): idaapi.set_processor_type("arm", SETPROC_ALL|SETPROC_FATAL) f = load_nxo(li) if f.armv7: idc.SetShortPrm(idc.INF_LFLAGS, idc.GetShortPrm(idc.INF_LFLAGS) | idc.LFLG_PC_FLAT) else: idc.SetShortPrm(idc.INF_LFLAGS, idc.GetShortPrm(idc.INF_LFLAGS) | idc.LFLG_64BIT) idc.SetCharPrm(idc.INF_DEMNAMES, idaapi.DEMNAM_GCC3) idaapi.set_compiler_id(idaapi.COMP_GNU) idaapi.add_til2('gnulnx_arm' if f.armv7 else 'gnulnx_arm64', 1) #loadbase = 0x60000000 if f.armv7 else 0x7100000000 loadbase = 0x80060000 f.binfile.seek(0) as_string = f.binfile.read(f.bssoff) idaapi.mem2base(as_string, loadbase) for start, end, name, kind in f.sections: if name.startswith('.got'): kind = 'CONST' idaapi.add_segm(0, loadbase+start, loadbase+end, name, kind) segm = idaapi.get_segm_by_name(name) if kind == 'CONST': segm.perm = idaapi.SEGPERM_READ elif kind == 'CODE': segm.perm = idaapi.SEGPERM_READ | idaapi.SEGPERM_EXEC elif kind == 'DATA': segm.perm = idaapi.SEGPERM_READ | idaapi.SEGPERM_WRITE elif kind == 'BSS': segm.perm = idaapi.SEGPERM_READ | idaapi.SEGPERM_WRITE idaapi.update_segm(segm) idaapi.set_segm_addressing(segm, 1 if f.armv7 else 2) # do imports # TODO: can we make imports show up in "Imports" window? undef_count = 0 for s in f.symbols: if not s.shndx and s.name: undef_count += 1 last_ea = max(loadbase + end for start, end, name, kind in f.sections) undef_entry_size = 8 undef_ea = ((last_ea + 0xFFF) & ~0xFFF) + undef_entry_size # plus 8 so we don't end up on the "end" symbol idaapi.add_segm(0, undef_ea, undef_ea+undef_count*undef_entry_size, "UNDEF", "XTRN") segm = idaapi.get_segm_by_name("UNDEF") segm.type = idaapi.SEG_XTRN idaapi.update_segm(segm) for i,s in enumerate(f.symbols): if not s.shndx and s.name: idc.MakeQword(undef_ea) idaapi.do_name_anyway(undef_ea, s.name) s.resolved = undef_ea undef_ea += undef_entry_size elif i != 0: assert s.shndx s.resolved = loadbase + s.value if s.name: if s.type == STT_FUNC: print hex(s.resolved), s.name idaapi.add_entry(s.resolved, s.resolved, s.name, 0) else: idaapi.do_name_anyway(s.resolved, s.name) else: # NULL symbol s.resolved = 0 funcs = set() for s in f.symbols: if s.name and s.shndx and s.value: if s.type == STT_FUNC: funcs.add(loadbase+s.value) got_name_lookup = {} for offset, r_type, sym, addend in f.relocations: target = offset + loadbase if r_type in (R_ARM_GLOB_DAT, R_ARM_JUMP_SLOT, R_ARM_ABS32): if not sym: print 'error: relocation at %X failed' % target else: idaapi.put_long(target, sym.resolved) elif r_type == R_ARM_RELATIVE: idaapi.put_long(target, idaapi.get_long(target) + loadbase) elif r_type in (R_AARCH64_GLOB_DAT, R_AARCH64_JUMP_SLOT, R_AARCH64_ABS64): idaapi.put_qword(target, sym.resolved + addend) if addend == 0: got_name_lookup[offset] = sym.name elif r_type == R_AARCH64_RELATIVE: idaapi.put_qword(target, loadbase + addend) if addend < f.textsize: funcs.add(loadbase + addend) else: print 'TODO r_type %d' % (r_type,) ida_make_offset(f, target) for func, target in f.plt_entries: if target in got_name_lookup: addr = loadbase + func funcs.add(addr) idaapi.do_name_anyway(addr, got_name_lookup[target]) funcs |= find_bl_targets(loadbase, loadbase+f.textsize) for addr in sorted(funcs, reverse=True): idc.AutoMark(addr, AU_CODE) idc.AutoMark(addr, AU_PROC) return 1