# This file is part of Metasm, the Ruby assembly manipulation suite # Copyright (C) 2007 Yoann GUILLOT # # Licence is LGPL, see LICENCE in the top-level directory # # this is a linux/x86 debugger with a console interface # require 'metasm' module Ansi CursHome = "\e[H".freeze ClearLineAfter = "\e[0K" ClearLineBefore = "\e[1K" ClearLine = "\e[2K" ClearScreen = "\e[2J" def self.set_cursor_pos(y=1,x=1) "\e[#{y};#{x}H" end Reset = "\e[m" Colors = [:black, :red, :green, :yellow, :blue, :magenta, :cyan, :white, :aoeu, :reset] def self.color(*args) fg = true "\e[" << args.map { |a| case a when :bold; 2 when :negative; 7 when :normal; 22 when :positive; 27 else if col = Colors.index(a) add = (fg ? 30 : 40) fg = false col+add end end }.compact.join(';') << 'm' end def self.hline(len) "\e(0"<<'q'*len<<"\e(B" end TIOCGWINSZ = 0x5413 TCGETS = 0x5401 TCSETS = 0x5402 CANON = 2 ECHO = 8 def self.get_terminal_size s = ''.ljust(8) $stdin.ioctl(TIOCGWINSZ, s) >= 0 ? s.unpack('SS') : [80, 25] end def self.set_term_canon(bool) tty = ''.ljust(256) $stdin.ioctl(TCGETS, tty) if bool tty[12] &= ~(ECHO|CANON) else tty[12] |= ECHO|CANON end $stdin.ioctl(TCSETS, tty) end ESC_SEQ = {'A' => :up, 'B' => :down, 'C' => :right, 'D' => :left, '1~' => :home, '2~' => :inser, '3~' => :suppr, '4~' => :end, '5~' => :pgup, '6~' => :pgdown, 'P' => :f1, 'Q' => :f2, 'R' => :f3, 'S' => :f4, '15~' => :f5, '17~' => :f6, '18~' => :f7, '19~' => :f8, '20~' => :f9, '21~' => :f10, '23~' => :f11, '24~' => :f12, '[A' => :f1, '[B' => :f2, '[C' => :f3, '[D' => :f4, '[E' => :f5, 'H' => :home, 'F' => :end, } def self.getkey c = $stdin.getc return c if c != ?\e c = $stdin.getc if c != ?[ and c != ?O $stdin.ungetc c return ?\e end seq = '' loop do c = $stdin.getc seq << c case c; when ?a..?z, ?A..?Z, ?~; break end end ESC_SEQ[seq] || seq end end class Indirect < Metasm::ExpressionType attr_accessor :ptr, :sz UNPACK_STR = {1 => 'C', 2 => 'S', 4 => 'L'} def initialize(ptr, sz) @ptr, @sz = ptr, sz end def bind(bd) raw = bd['tracer_memory'][@ptr.bind(bd).reduce, @sz] Metasm::Expression[raw.unpack(UNPACK_STR[@sz]).first] end def externals ; @ptr.externals end end class ExprParser < Metasm::Expression def self.parse_intfloat(lex, tok) case tok.raw when 'byte', 'word', 'dword' nil while ntok = lex.readtok and ntok.type == :space nil while ntok = lex.readtok and ntok.type == :space if ntok and ntok.raw == 'ptr' if ntok and ntok.raw == '[' tok.value = Indirect.new(parse(lex), {'byte' => 1, 'word' => 2, 'dword' => 4}[tok.raw]) nil while ntok = lex.readtok and ntok.type == :space nil while ntok = lex.readtok and ntok.type == :space if ntok and ntok.raw == ']' lex.unreadtok ntok end else super end end def self.parse_value(lex) nil while tok = lex.readtok and tok.type == :space lex.unreadtok tok if tok and tok.type == :punct and tok.raw == '[' tt = tok.dup tt.type = :string tt.raw = 'dword' lex.unreadtok tt end super end end class LinDebug attr_accessor :win_data_height, :win_code_height, :win_prpt_height def init_screen Ansi.set_term_canon(true) @win_data_height = 20 @win_code_height = 20 resize end def fini_screen Ansi.set_term_canon(false) end def win_data_start; 2 end def win_code_start; win_data_start+win_data_height end def win_prpt_start; win_code_start+win_code_height end Color = {:changed => Ansi.color(:cyan, :bold), :border => Ansi.color(:green), :normal => Ansi.color(:white, :black, :normal), :hilight => Ansi.color(:blue, :white, :normal), :status => Ansi.color(:black, :cyan)} attr_accessor :dataptr, :codeptr, :rs, :promptlog def initialize(rs) @rs = rs @rs.logger = self @dataptr = 0 @datafmt = 'db' @prompthistlen = 20 @prompthistory = [] @promptloglen = 200 @promptlog = [] @promptbuf = '' @promptpos = 0 @log_off = 0 @focus = :prompt @command = {} load_commands trap('WINCH') { resize } stack = @rs[@rs.regs_cache['esp'], 0x1000].unpack('L*') stack.shift # argc stack.shift until stack.empty? or stack.first == 0 # argv stack.shift stack.shift until stack.empty? or stack.first == 0 # envp stack.shift stack.shift until stack.empty? or stack.shift == 3 # find PHDR ptr in auxv if phdr = stack.shift phdr &= 0xffff_f000 @rs.loadsyms phdr, phdr.to_s(16) end end def main_loop begin begin init_screen main_loop_inner rescue Errno::ESRCH log "target does not exist anymore" ensure fini_screen $stdout.print Ansi.set_cursor_pos(@console_height, 1) end rescue $stdout.puts $!, $!.backtrace end $stdout.puts @promptlog.last end def update csy, csx = @console_height-1, @promptpos+2 $stdout.write Ansi.set_cursor_pos(0, 0) + updateregs + updatedata + updatecode + updateprompt + Ansi.set_cursor_pos(csy, csx) end def updateregs text = '' text << ' ' x = 1 %w[eax ebx ecx edx eip].each { |r| text << Color[:changed] if @rs.regs_cache[r] != @rs.oldregs[r] text << r << ?= text << ('%08X' % @rs.regs_cache[r]) text << Color[:normal] if @rs.regs_cache[r] != @rs.oldregs[r] text << ' ' x += r.length + 11 } text << (' '*(@console_width-x)) << "\n" << ' ' x = 1 %w[esi edi ebp esp].each { |r| text << Color[:changed] if @rs.regs_cache[r] != @rs.oldregs[r] text << r << ?= text << ('%08X' % @rs.regs_cache[r]) text << Color[:normal] if @rs.regs_cache[r] != @rs.oldregs[r] text << ' ' x += r.length + 11 } Rubstop::EFLAGS.sort.each { |off, flag| val = @rs.regs_cache['eflags'] & (1<= @rs.regs_cache['eip'] addr = @rs.oldregs['eip'] else addr = @rs.regs_cache['eip'] end @codeptr = addr if @rs.findfilemap(addr) == '???' base = addr & 0xffff_f000 8.times { sig = @rs[base, 4] if sig == "\x7fELF" @rs.loadsyms(base, base.to_s(16)) break end base -= 0x1000 } end text = '' text << Color[:border] title = @rs.findsymbol(addr) pre = [@console_width-100, 6].max post = @console_width - (pre + title.length + 2) text << Ansi.hline(pre) << ' ' << title << ' ' << Ansi.hline(post) text << Color[:normal] text << "\n" cnt = @win_code_height while (cnt -= 1) > 0 if @rs.symbols[addr] text << (' ' << @rs.symbols[addr] << ?:) << Ansi::ClearLineAfter << "\n" break if (cnt -= 1) <= 0 end text << Color[:hilight] if addr == @rs.regs_cache['eip'] text << ('%04X' % @rs.regs_cache['cs']) << ':' text << ('%08X' % addr) di = @rs.mnemonic_di(addr) di = nil if di and addr < @rs.regs_cache['eip'] and addr+di.bin_length > @rs.regs_cache['eip'] len = (di ? di.bin_length : 1) text << ' ' text << @rs[addr, [len, 10].min].unpack('C*').map { |c| '%02X' % c }.join.ljust(22) if di text << if addr == @rs.regs_cache['eip'] "*#{di.instruction}".ljust(@console_width-37) else " #{di.instruction}" << Ansi::ClearLineAfter end else text << ' ' << Ansi::ClearLineAfter end text << Color[:normal] if addr == @rs.regs_cache['eip'] addr += len text << "\n" end text end def updatedata @dataptr &= 0xffff_ffff addr = @dataptr text = '' text << Color[:border] title = @rs.findsymbol(addr) pre = [@console_width-100, 6].max post = @console_width - (pre + title.length + 2) text << Ansi.hline(pre) << ' ' << title << ' ' << Ansi.hline(post) text << Color[:normal] cnt = @win_data_height while (cnt -= 1) > 0 raw = @rs[addr, 16] text << ('%04X' % @rs.regs_cache['ds']) << ':' << ('%08X' % addr) << ' ' case @datafmt when 'db'; text << raw[0,8].unpack('C*').map { |c| '%02x ' % c }.join << ' ' << raw[8,8].unpack('C*').map { |c| '%02x ' % c }.join when 'dw'; text << raw.unpack('S*').map { |c| '%04x ' % c }.join when 'dd'; text << raw.unpack('L*').map { |c| '%08x ' % c }.join end text << ' ' << raw.unpack('C*').map { |c| (0x20..0x7e).include?(c) ? c : ?. }.pack('C*') text << Ansi::ClearLineAfter << "\n" addr += 16 end text end def updateprompt text = '' text << Color[:border] << Ansi.hline(@console_width) << Color[:normal] << "\n" @log_off = @promptlog.length - 2 if @log_off >= @promptlog.length @log_off = 0 if @log_off < 0 len = @win_prpt_height - 2 len.times { |i| i += @promptlog.length - @log_off - len text << ((@promptlog[i] if i >= 0) || '') text << Ansi::ClearLineAfter << "\n" } text << ':' << @promptbuf << Ansi::ClearLineAfter << "\n" text << Color[:status] << statusline.ljust(@console_width) << Color[:normal] end def statusline ' Enter a command (help for help)' end def resize @console_height, @console_width = Ansi.get_terminal_size @win_data_height = 1 if @win_data_height < 1 @win_code_height = 1 if @win_code_height < 1 if @win_data_height + @win_code_height + 5 > @console_height @win_data_height = @console_height/2 - 4 @win_code_height = @console_height/2 - 4 end @win_prpt_height = @console_height-(@win_data_height+@win_code_height+2) - 1 update end def log(str) raise str.inspect if not str.kind_of? ::String @promptlog << str @promptlog.shift if @promptlog.length > @promptloglen end def puts(*s) s.each { |s| log s.to_s } update rescue nil end def mem_binding(expr) b = @rs.regs_cache.dup ext = expr.externals (ext - @rs.regs_cache.keys).each { |ex| if not s = @rs.symbols.index(ex) log "unknown value #{ex}" return {} end b[ex] = s if @rs.symbols.values.grep(ex).length > 1 raise "multiple definitions found for #{ex}" end } b['tracer_memory'] = @rs b end def exec_prompt @log_off = 0 log ':'+@promptbuf return if @promptbuf == '' lex = Metasm::Preprocessor.new.feed @promptbuf @prompthistory << @promptbuf @prompthistory.shift if @prompthistory.length > @prompthistlen @promptbuf = '' @promptpos = @promptbuf.length argint = proc { begin raise if not e = ExprParser.parse(lex) rescue log 'syntax error' return end e.bind(mem_binding(e)).reduce } cmd = lex.readtok cmd = cmd.raw if cmd nil while ntok = lex.readtok and ntok.type == :space lex.unreadtok ntok if @command.has_key? cmd @command[cmd].call(lex, argint) else if cmd and (poss = @command.keys.find_all { |c| c[0, cmd.length] == cmd }).length == 1 @command[poss.first].call(lex, argint) else log 'unknown command' end end end def updatecodeptr @codeptr ||= @rs.regs_cache['eip'] if @codeptr > @rs.regs_cache['eip'] or @codeptr < @rs.regs_cache['eip'] - 6*@win_code_height @codeptr = @rs.regs_cache['eip'] elsif @codeptr != @rs.regs_cache['eip'] addr = @codeptr addrs = [] while addr < @rs.regs_cache['eip'] addrs << addr o = @rs.mnemonic_di(addr).bin_length addr += ((o == 0) ? 1 : o) end if addrs.length > @win_code_height-4 @codeptr = addrs[-(@win_code_height-4)] end end updatedataptr end def updatedataptr @dataptr = @watch.bind(mem_binding(@watch)).reduce if @watch end def singlestep @rs.singlestep updatecodeptr end def stepover @rs.stepover updatecodeptr end def cont(*a) @rs.cont(*a) updatecodeptr end def stepout @rs.stepout updatecodeptr end def syscall @rs.syscall updatecodeptr end def main_loop_inner @prompthistory = [''] @histptr = nil @running = true update while @running if not IO.select [$stdin], nil, nil, 0 begin update rescue Errno::ESRCH break end end break if handle_keypress(Ansi.getkey) end @rs.checkbp end def handle_keypress(k) case k when 4; log 'exiting'; return true # eof when ?\e; focus = :prompt when :f5; cont when :f6 syscall log Rubstop::SYSCALLNR.index(@rs.regs_cache['orig_eax']) || @rs.regs_cache['orig_eax'].to_s when :f10; stepover when :f11; singlestep when :f12; stepout when :up case @focus when :prompt if not @histptr @prompthistory << @promptbuf @histptr = 2 else @histptr += 1 @histptr = 1 if @histptr > @prompthistory.length end @promptbuf = @prompthistory[-@histptr].dup @promptpos = @promptbuf.length when :data @dataptr -= 16 when :code @codeptr ||= @rs.regs_cache['eip'] @codeptr -= (1..10).find { |off| di = @rs.mnemonic_di(@codeptr-off) di.bin_length == off if di } || 10 end when :down case @focus when :prompt if not @histptr @prompthistory << @promptbuf @histptr = @prompthistory.length else @histptr -= 1 @histptr = @prompthistory.length if @histptr < 1 end @promptbuf = @prompthistory[-@histptr].dup @promptpos = @promptbuf.length when :data @dataptr += 16 when :code @codeptr ||= @rs.regs_cache['eip'] di = @rs.mnemonic_di(@codeptr) @codeptr += (di ? (di.bin_length || 1) : 1) end when :left; @promptpos -= 1 if @promptpos > 0 when :right; @promptpos += 1 if @promptpos < @promptbuf.length when :home; @promptpos = 0 when :end; @promptpos = @promptbuf.length when :backspace, 0x7f; @promptbuf[@promptpos-=1, 1] = '' if @promptpos > 0 when :suppr; @promptbuf[@promptpos, 1] = '' if @promptpos < @promptbuf.length when :pgup case @focus when :prompt; @log_off += @win_prpt_height-3 when :data; @dataptr -= 16*(@win_data_height-1) when :code @codeptr ||= @rs.regs_cache['eip'] (@win_code_height-1).times { @codeptr -= (1..10).find { |off| di = @rs.mnemonic_di(@codeptr-off) di.bin_length == off if di } || 10 } end when :pgdown case @focus when :prompt; @log_off -= @win_prpt_height-3 when :data; @dataptr += 16*(@win_data_height-1) when :code @codeptr ||= @rs.regs_cache['eip'] (@win_code_height-1).times { @codeptr += (((o = @rs.mnemonic_di(@codeptr).bin_length) == 0) ? 1 : o) } end when ?\t if not @promptbuf[0, @promptpos].include? ' ' poss = @command.keys.find_all { |c| c[0, @promptpos] == @promptbuf[0, @promptpos] } if poss.length > 1 log poss.sort.join(' ') elsif poss.length == 1 @promptbuf[0, @promptpos] = poss.first + ' ' @promptpos = poss.first.length+1 end end when ?\n; @histptr = nil ; exec_prompt rescue log "error: #$!" when 0x20..0x7e @promptbuf[@promptpos, 0] = k.chr @promptpos += 1 else log "unknown key pressed #{k.inspect}" end nil end def load_commands ntok = nil @command['kill'] = proc { |lex, int| @rs.kill @running = false log 'killed' } @command['quit'] = @command['detach'] = @command['exit'] = proc { |lex, int| @rs.detach @running = false } @command['closeui'] = proc { |lex, int| @rs.logger = nil @running = false } @command['bpx'] = proc { |lex, int| addr = int[] @rs.bpx addr } @command['bphw'] = proc { |lex, int| type = lex.readtok.raw addr = int[] @rs.set_hwbp type, addr } @command['bl'] = proc { |lex, int| log "bpx at #{@rs.findsymbol(@rs.wantbp)}" if @rs.wantbp.kind_of? ::Integer @rs.breakpoints.sort.each { |addr, oct| log "bpx at #{@rs.findsymbol(addr)}" } (0..3).each { |dr| if @rs.regs_cache['dr7'] & (1 << (2*dr)) != 0 log "bphw #{{0=>'x', 1=>'w', 2=>'?', 3=>'r'}[(@rs.regs_cache['dr7'] >> (16+4*dr)) & 3]} at #{@rs.findsymbol(@rs.regs_cache["dr#{dr}"])}" end } } @command['bc'] = proc { |lex, int| @rs.wantbp = nil if @rs.wantbp == @rs.regs_cache['eip'] @rs.breakpoints.each { |addr, oct| @rs[addr] = oct } @rs.breakpoints.clear if @rs.regs_cache['dr7'] & 0xff != 0 @rs.dr7 = 0 @rs.readregs end } @command['bt'] = proc { |lex, int| @rs.backtrace.each { |t| puts t } } @command['d'] = proc { |lex, int| @dataptr = int[] || return } @command['db'] = proc { |lex, int| @datafmt = 'db' ; @dataptr = int[] || return } @command['dw'] = proc { |lex, int| @datafmt = 'dw' ; @dataptr = int[] || return } @command['dd'] = proc { |lex, int| @datafmt = 'dd' ; @dataptr = int[] || return } @command['r'] = proc { |lex, int| r = lex.readtok.raw nil while ntok = lex.readtok and ntok.type == :space if r == 'fl' flag = ntok.raw if i = Rubstop::EFLAGS.index(flag) @rs.eflags ^= 1 << i @rs.readregs else log "bad flag #{flag}" end elsif not @rs.regs_cache[r] log "bad reg #{r}" elsif ntok lex.unreadtok ntok newval = int[] if newval and newval.kind_of? ::Integer @rs.send r+'=', newval @rs.readregs end else log "#{r} = #{@rs.regs_cache[r]}" end } @command['run'] = @command['cont'] = proc { |lex, int| if tok = lex.readtok lex.unreadtok tok cont int[] else cont end } @command['syscall'] = proc { |lex, int| syscall } @command['singlestep'] = proc { |lex, int| singlestep } @command['stepover'] = proc { |lex, int| stepover } @command['stepout'] = proc { |lex, int| stepout } @command['g'] = proc { |lex, int| @rs.bpx int[], true ; cont } @command['u'] = proc { |lex, int| @codeptr = int[] || break } @command['has_pax'] = proc { |lex, int| if tok = lex.readtok lex.unreadtok tok @rs.has_pax = (int[] != 0) else @rs.has_pax = !@rs.has_pax end log "has_pax now #{@rs.has_pax}" } @command['loadsyms'] = proc { |lex, int| @rs.loadallsyms } @command['scansyms'] = proc { |lex, int| @rs.scansyms } @command['sym'] = proc { |lex, int| sym = '' sym << ntok.raw while ntok = lex.readtok s = @rs.symbols.values.grep(/#{sym}/) if s.empty? log "unknown symbol #{sym}" else s = @rs.symbols.keys.find_all { |k| s.include? @rs.symbols[k] } s.sort.each { |s| log "#{'%08x' % s} #{@rs.symbols_len[s].to_s.ljust 6} #{@rs.findsymbol(s)}" } end } @command['delsym'] = proc { |lex, int| addr = int[] log "deleted #{@rs.symbols.delete addr}" @rs.symbols_len.delete addr } @command['addsym'] = proc { |lex, int| name = lex.readtok.raw addr = int[] if t = lex.readtok lex.unreadtok t @rs.symbols_len[addr] = int[] else @rs.symbols_len[addr] = 1 end @rs.symbols[addr] = name } @command['help'] = proc { |lex, int| log 'commands: (addr/values are things like dword ptr [ebp+(4*byte [eax])] ), type to see all commands' log ' bpx ' log ' bphw [r|w|x] : debug register breakpoint' log ' bl: list breakpoints' log ' bc: clear breakpoints' log ' cont []: continue the target sending a signal' log ' d/db/dw/dd []: change data type/address' log ' g : set a bp at and run' log ' has_pax [0|1]: set has_pax flag (hwbp+0x60000000 instead of bpx)' log ' r []: show/change register' log ' r fl : toggle eflags bit' log ' loadsyms: load symbol information from mapped files (from /proc and disk)' log ' scansyms: scan memory for ELF headers' log ' sym : show symbol information' log ' addsym []' log ' delsym ' log ' u : disassemble addr' log ' reload: reload lindebug source' log ' ruby : instance_evals ruby code in current instance' log ' closeui: detach from the underlying RubStop' log 'keys:' log ' F5: continue' log ' F6: syscall' log ' F10: step over' log ' F11: single step' log ' F12: step out (til next ret)' log ' pgup/pgdown: move command history' } @command['reload'] = proc { |lex, int| load $0 ; load_commands } @command['ruby'] = proc { |lex, int| str = '' str << ntok.raw while ntok = lex.readtok instance_eval str } @command['maps'] = proc { |lex, int| @rs.filemap.sort_by { |f, (b, e)| b }.each { |f, (b, e)| log "#{f.ljust 20} #{'%08x' % b} - #{'%08x' % e}" } } @command['resize'] = proc { |lex, int| resize } @command['watch'] = proc { |lex, int| @watch = ExprParser.parse(lex) ; updatedataptr } @command['wd'] = proc { |lex, int| @focus = :data if tok = lex.readtok lex.unreadtok tok @win_data_height = int[] || return resize end } @command['wc'] = proc { |lex, int| @focus = :code if tok = lex.readtok lex.unreadtok tok @win_code_height = int[] || return resize end } @command['wp'] = proc { |lex, int| @focus = :prompt } @command['?'] = proc { |lex, int| val = int[] log "#{val} 0x#{val.to_s(16)} #{[val].pack('L').inspect}" } @command['.'] = proc { |lex, int| @codeptr = nil } end end if $0 == __FILE__ begin require 'samples/rubstop' rescue LoadError if not defined? Rubstop $: << File.dirname(__FILE__) require 'rubstop' $:.pop end end LinDebug.new(Rubstop.new(ARGV.join(' '))).main_loop end