分析Mach-O文件

2018-07-21 本文已影响4人 ZhongXi

OSX系统自带的otool可以分析Mach-O可执行文件
类似命令行工具:jtool
常用命令如下:

查看fat headers信息

otool -f xxx.app/xxx

$ otool -f xxx.app/xxx
Fat headers
fat_magic 0xcafebabe
nfat_arch 2
architecture 0
    cputype 12
    cpusubtype 9
    capabilities 0x0
    offset 16384
    size 69642576
    align 2^14 (16384)
architecture 1
    cputype 16777228
    cpusubtype 0
    capabilities 0x0
    offset 69664768
    size 80306624
    align 2^14 (16384)

查看archive header信息

otool -a xxx.app/xxx

$ otool -a xxx.app/xxx

查看Mach-O头结构

otool -h xxx.app/xxx

$ otool -h xxx.app/xxx
Mach header
      magic cputype cpusubtype  caps    filetype ncmds sizeofcmds      flags
 0xfeedface      12          9  0x00           2    52       5452 0x00218085
Mach header
      magic cputype cpusubtype  caps    filetype ncmds sizeofcmds      flags
 0xfeedfacf 16777228          0  0x00           2    52       6128 0x00218085

查看load commands

otool -l xxx.app/xxx

$ otool -l xxx.app/xxx
Mach header
      magic cputype cpusubtype  caps    filetype ncmds sizeofcmds      flags
 0xfeedface      12          9  0x00           2    52       5452 0x00218085
Load command 0
      cmd LC_SEGMENT
  cmdsize 56
  segname __PAGEZERO
   vmaddr 0x00000000
   vmsize 0x00004000
  fileoff 0
 filesize 0
  maxprot 0x00000000
 initprot 0x00000000
   nsects 0
    flags 0x0
Load command 1
      cmd LC_SEGMENT
  cmdsize 736
  segname __TEXT
   vmaddr 0x00004000
   vmsize 0x03b44000
  fileoff 0
 filesize 62144512
  maxprot 0x00000005
 initprot 0x00000005
   nsects 10
    flags 0x0
Section
  sectname __text
   segname __TEXT
      addr 0x000092c0
      size 0x01f49bcc
    offset 21184
     align 2^4 (16)
    reloff 0
    nreloc 0
     flags 0x80000400
 reserved1 0
 reserved2 0

查看依赖的动态库,包括动态库名称、当前版本号、兼容版本号

otool -L xxx.app/xxx

$ otool -L xxx.app/xxx
xxx.app/xxx (architecture armv7):
    /System/Library/Frameworks/CoreMotion.framework/CoreMotion (compatibility version 1.0.0, current version 2236.0.11)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1252.0.0)
    /System/Library/Frameworks/CoreText.framework/CoreText (compatibility version 1.0.0, current version 1.0.0)
    /System/Library/Frameworks/AudioToolbox.framework/AudioToolbox (compatibility version 1.0.0, current version 492.0.0)
    /System/Library/Frameworks/AVFoundation.framework/AVFoundation (compatibility version 1.0.0, current version 2.0.0)
xxx.app/xxx (architecture arm64):
    /System/Library/Frameworks/CoreMotion.framework/CoreMotion (compatibility version 1.0.0, current version 2236.0.11)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1252.0.0)
    /System/Library/Frameworks/CoreText.framework/CoreText (compatibility version 1.0.0, current version 1.0.0)
    /System/Library/Frameworks/AudioToolbox.framework/AudioToolbox (compatibility version 1.0.0, current version 492.0.0)
    /System/Library/Frameworks/AVFoundation.framework/AVFoundation (compatibility version 1.0.0, current version 2.0.0)

查看支持的框架

otool -D xxx.app/xxx

$ otool -D xxx.app/xxx
xxx.app/xxx (architecture armv7):
xxx.app/xxx (architecture arm64):

查看text section
otool -t -v xxx.app/xxx

$ otool -t -v xxx.app/xxx
xxx.app/xxx (architecture armv7):
(__TEXT,__text) section
000092c0    f0 b5   push    {r4, r5, r6, r7, lr}
000092c2    03 af   add r7, sp, #0xc
000092c4    2d e9 00 0d     push.w  {r8, r10, r11}
000092c8    ad f5 78 6d     sub.w   sp, sp, #0xf80
000092cc    82 b0   sub sp, #0x8
000092ce    4c f2 2e 20     movw    r0, #0xc22e
000092d2    c0 f2 fc 30     movt    r0, #0x3fc
000092d6    78 44   add r0, pc
000092d8    d0 f8 00 80     ldr.w   r8, [r0]
000092dc    42 f2 b8 20     movw    r0, #0x22b8
000092e0    c0 f2 c9 30     movt    r0, #0x3c9
000092e4    78 44   add r0, pc
000092e6    41 46   mov r1, r8
000092e8    02 46   mov r2, r0
...
xxx.app/xxx (architecture arm64):
(__TEXT,__text) section
000092c0    f0 b5   push    {r4, r5, r6, r7, lr}
000092c2    03 af   add r7, sp, #0xc
000092c4    2d e9 00 0d     push.w  {r8, r10, r11}
000092c8    ad f5 78 6d     sub.w   sp, sp, #0xf80
000092cc    82 b0   sub sp, #0x8
000092ce    4c f2 2e 20     movw    r0, #0xc22e
000092d2    c0 f2 fc 30     movt    r0, #0x3fc
000092d6    78 44   add r0, pc
000092d8    d0 f8 00 80     ldr.w   r8, [r0]
000092dc    42 f2 b8 20     movw    r0, #0x22b8
000092e0    c0 f2 c9 30     movt    r0, #0x3c9
000092e4    78 44   add r0, pc
000092e6    41 46   mov r1, r8
000092e8    02 46   mov r2, r0
...

查看data section

otool -d xxx.app/xxx

$ otool -d xxx.app/xxx
xxx.app/xxx (architecture armv7):
Contents of (__DATA,__data) section
03fdf2d0    01f94e98 01fef35b 01fef376 00000000 
03fdf2e0    037b0c7d 00000000 03fb44bc 00000000 
03fdf2f0    03fb45a8 00000000 03fb45bc 00000034 
03fdf300    00000000 03fb45e4 00000000 00000000 
03fdf310    00000000 037b0c65 03fb4634 00000000 
xxx.app/xxx (architecture arm64):
Contents of (__DATA,__data) section
0000000104a01100    02435948 00000001 0248fe0b 00000001 
0000000104a01110    0248fe26 00000001 00000000 00000000 
0000000104a01120    03c5113a 00000001 00000000 00000000 
0000000104a01130    049b2700 00000001 00000000 00000000 
0000000104a01140    049b28d0 00000001 00000000 00000000

查看Objective-C segment

otool -o xxx.app/xxx

$ otool -o xxx.app/xxx
xxx.app/xxx (architecture armv7):
Contents of (__DATA,__objc_classlist) section
03fb3690 0x3fda424
           isa 0x3fda410
    superclass 0x0
         cache 0x0
        vtable 0x0
          data 0x3fb4304 (struct class_ro_t *)
                    flags 0x90
            instanceStart 4
             instanceSize 4
               ivarLayout 0x0
                     name 0x37b0c31 GICQgdiSTB
              baseMethods 0x0 (struct method_list_t *)
            baseProtocols 0x0
                    ivars 0x0
           weakIvarLayout 0x0
           baseProperties 0x0
Meta Class
           isa 0x0
    superclass 0x0
         cache 0x0
        vtable 0x0
          data 0x3fb42dc (struct class_ro_t *)
                    flags 0x91 RO_META
            instanceStart 20
             instanceSize 20
               ivarLayout 0x0
                     name 0x37b0c31 GICQgdiSTB
              baseMethods 0x3fb42c8 (struct method_list_t *)
           entsize 12
             count 1
              name 0x3799743 load
             types 0x37b3155 v8@0:4
               imp 0x92c1
            baseProtocols 0x0
                    ivars 0x0
           weakIvarLayout 0x0
           baseProperties 0x0
...
xxx.app/xxx (architecture arm64):
Contents of (__DATA,__objc_classlist) section
00000001049b0b38 0x1049f73a8
           isa 0x1049f7380
    superclass 0x0 _OBJC_CLASS_$_NSObject
         cache 0x0
        vtable 0x0
          data 0x1049b23f8 (struct class_ro_t *)
                    flags 0x90
            instanceStart 8
             instanceSize 8
                 reserved 0x0
               ivarLayout 0x0
                     name 0x103c510ee GICQgdiSTB
              baseMethods 0x0 (struct method_list_t *)
            baseProtocols 0x0
                    ivars 0x0
           weakIvarLayout 0x0
           baseProperties 0x0
Meta Class
           isa 0x0
    superclass 0x0 _OBJC_METACLASS_$_NSObject
         cache 0x0
        vtable 0x0
          data 0x1049b23b0 (struct class_ro_t *)
                    flags 0x91 RO_META
            instanceStart 40
             instanceSize 40
                 reserved 0x0
               ivarLayout 0x0
                     name 0x103c510ee GICQgdiSTB
              baseMethods 0x1049b2390 (struct method_list_t *)
           entsize 24
             count 1
              name 0x103c39c13 load
             types 0x103c535db v16@0:8
               imp 0x1000058f0 
            baseProtocols 0x0
                    ivars 0x0
           weakIvarLayout 0x0
           baseProperties 0x0

查看symbol table

otool -I xxx.app/xxx

$ otool -I xxx.app/xxx
xxx.app/xxx (architecture armv7):
Indirect symbols for (__TEXT,__picsymbolstub4__TEXT) 815 entries
address    index
0x01f52e8c   491 
0x01f52e9c   492 
0x01f52eac   493 
0x01f52ebc   494 
0x01f52ecc   495
...
xxx.app/xxx (architecture arm64):
Indirect symbols for (__TEXT,__stubs) 824 entries
address            index
0x00000001023f470c    52 
0x00000001023f4718    53 
0x00000001023f4724    54 
0x00000001023f4730    55 
0x00000001023f473c    56
...

获取所有方法名称:

otool -v -s __TEXT __objc_methname xxx.app/xxx

$ otool -v -s __TEXT __objc_methname xxx.app/xxx
xxx.app/xxx (architecture armv7):
Contents of (__TEXT,__objc_methname) section
0379972a  stringByAppendingString:
03799743  load
03799748  stringWithUTF8String:
0379975e  user
03799763  setUser:
0379976c  password
03799775  setPassword:
...
xxx.app/xxx (architecture arm64):
Contents of (__TEXT,__objc_methname) section
0000000103c39bfa  stringByAppendingString:
0000000103c39c13  load
0000000103c39c18  stringWithUTF8String:
0000000103c39c2e  user
0000000103c39c33  setUser:
0000000103c39c3c  password
0000000103c39c45  setPassword:
...

下面列举一些常见的 Section。

Section	用途
`__TEXT.__text`	主程序代码
`__TEXT.__cstring`	C 语言字符串
`__TEXT.__const`	`const` 关键字修饰的常量
`__TEXT.__stubs`	用于 Stub 的占位代码，很多地方称之为桩代码。
`__TEXT.__stubs_helper`	当 Stub 无法找到真正的符号地址后的最终指向
`__TEXT.__objc_methname`	Objective-C 方法名称
`__TEXT.__objc_methtype`	Objective-C 方法类型
`__TEXT.__objc_classname`	Objective-C 类名称
`__DATA.__data`	初始化过的可变数据
`__DATA.__la_symbol_ptr`	lazy binding 的指针表，表中的指针一开始都指向 `__stub_helper`
`__DATA.nl_symbol_ptr`	非 lazy binding 的指针表，每个表项中的指针都指向一个在装载过程中，被动态链机器搜索完成的符号
`__DATA.__const`	没有初始化过的常量
`__DATA.__cfstring`	程序中使用的 Core Foundation 字符串（`CFStringRefs`）
`__DATA.__bss`	BSS，存放为初始化的全局变量，即常说的静态内存分配
`__DATA.__common`	没有初始化过的符号声明
`__DATA.__objc_classlist`	Objective-C 类列表
`__DATA.__objc_protolist`	Objective-C 原型
`__DATA.__objc_imginfo`	Objective-C 镜像信息
`__DATA.__objc_selfrefs`	Objective-C `self` 引用
`__DATA.__objc_protorefs`	Objective-C 原型引用
`__DATA.__objc_superrefs`	Objective-C 超类引用

分析Mach-O文件

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