标签：ios逆向工程
本来是打算用AppCrackr砸壳的，结果砸壳都是失败的，开始以为是App的加密太厉害了，后来才知道是因为AppCrackr太暴力了，引起公愤，结果被人投诉招致核心功能被迫关闭了。
幸好在RE官网搜到一个用dumpdecrypted砸壳的帖子。下面是我砸壳的经历。
下载地址：https://github.com/stefanesser/dumpdecrypted/archive/master.zip，接着在Mac中解压。
iOS 7.1.x，原帖中snakeninny略啰嗦。。。
cd到dumpdecrypted目录，看看Makefile文件的内容：
CC_BIN=`xcrun --sdk iphoneos --find gcc`
GCC_UNIVERSAL=$(GCC_BASE) -arch armv7 -arch armv7s -arch arm64
SDK=`xcrun --sdk iphoneos --show-sdk-path`
CFLAGS =
GCC_BASE = $(GCC_BIN) -Os $(CFLAGS) -Wimplicit -isysroot $(SDK) -F$(SDK)/System$
all: dumpdecrypted.dylib
dumpdecrypted.dylib: dumpdecrypted.o
$(GCC_UNIVERSAL) -dynamiclib -o $@ $^
%.o: %.c
$(GCC_UNIVERSAL) -c -o $@ $<
clean:
rm -f *.o dumpdecrypted.dylib接下来我们需要确认的是GCC_UNIVERSAL和SDK这两个变量的值和iOS设备的环境保持一致。
在Mac中打开终端，输入xcrun --sdk iphoneos --show-sdk-path命令，查看SDK版本：
/Applications/Xcode 5.1.1.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.1.sdk
在确保Makefile中对动态库的设置和iOS真机环境一致后，在当前目录下输入：make。
但是失败了，错误信息如下：
`xcrun --sdk iphoneos --find gcc` -Os -Wimplicit -isysroot `xcrun --sdk iphoneos --show-sdk-path` -F`xcrun --sdk iphoneos --show-sdk-path`/System/Library/Frameworks -F`xcrun --sdk iphoneos --show-sdk-path`/System/Library/PrivateFrameworks -arch armv7 -arch armv7s -arch arm64 -c -o dumpdecrypted.o dumpdecrypted.c /bin/sh: /Applications/Xcode: No such file or directory make: *** [dumpdecrypted.o] Error 127
原因是找不到/Applications/Xcode来执行其中的一些脚本。 好吧，我的Mac中有3个Xcode：/Applications/Xcode 5.0.2, /Applications/Xcode 5.1.1, /Applications/Xcode 6 Beta4，就是没有/Applications/Xcode。
没事，将Xcode 5.1.1重命名为Xcode就行了：
$ sudo mv Xcode\ 5.1.1.app/ Xcode.app/
再make，还是报错，错误信息和上面一样。
不怕，我们还有xcode-select这个小伙伴，通常Xcode找不到之类的错误都应该找它帮忙：
$ xcode-select -p /Applications/Xcode 5.1.1.app/Contents/Developer
$ sudo xcode-select -r $ xcode-select -p /Applications/Xcode.app/Contents/Developer
再make，成功，输出如下：
$ make `xcrun --sdk iphoneos --find gcc` -Os -Wimplicit -isysroot `xcrun --sdk iphoneos --show-sdk-path` -F`xcrun --sdk iphoneos --show-sdk-path`/System/Library/Frameworks -F`xcrun --sdk iphoneos --show-sdk-path`/System/Library/PrivateFrameworks -arch armv7 -arch armv7s -arch arm64 -c -o dumpdecrypted.o dumpdecrypted.c `xcrun --sdk iphoneos --find gcc` -Os -Wimplicit -isysroot `xcrun --sdk iphoneos --show-sdk-path` -F`xcrun --sdk iphoneos --show-sdk-path`/System/Library/Frameworks -F`xcrun --sdk iphoneos --show-sdk-path`/System/Library/PrivateFrameworks -arch armv7 -arch armv7s -arch arm64 -dynamiclib -o dumpdecrypted.dylib dumpdecrypted.o $ ls Makefile dumpdecrypted.c dumpdecrypted.o README dumpdecrypted.dylib
查看iOS设备的IP地址，然后在Mac上使用scp命令将dumpdecrypted.dylib文件放到iOS设备中：
$ scp dumpdecrypted.dylib root@192.168.xxx.xxx:/var/tmp root@192.168.xxx.xxx's password: dumpdecrypted.dylib 100% 81KB 81.0KB/s 00:00
选定一个让你觉得非常不爽或非常感兴趣的app，我就随便选了一个HBGC。在iOS设备上打开iFile，查到它的可执行文件的路径为：/var/mobile/Applications/EBBD26E9-DDBA-481E-9403-84D159436889/HBGC.app/HBGC
然后用SSH连到iOS设备上，cd到刚刚动态库的路径：/var/tmp。
$ ssh root@192.168.xxx.xxx root@192.168.xxx.xxx's password: root# cd /var/tmp/ root# ls FlipswitchCache/ com.apple.audio.hogmode.plist L65ancd.sock= com.apple.tccd/ L65d.sock= com.apple.timed.plist MediaCache/ cydia.log RestoreFromBackupLock* dumpdecrypted.dylib* SpringBoard_reboot_flag launchd/ com.apple.assistant.bundleservicecache.plist mobile_assertion_agent.log
砸壳（久等了）：
root# DYLD_INSERT_LIBRARIES=dumpdecrypted.dylib /var/mobile/Applications/EBBD26E9-DDBA-481E-9403-84D159436889/HBGC.app/HBGC mach-o decryption dumper DISCLAIMER: This tool is only meant for security research purposes, not for application crackers. [+] detected 32bit ARM binary in memory. [+] offset to cryptid found: @0xd5a90(from 0xd5000) = a90 [+] Found encrypted data at address 00004000 of length 3047424 bytes - type 1. [+] Opening /private/var/mobile/Applications/EBBD26E9-DDBA-481E-9403-84D159436889/HBGC.app/HBGC for reading. [+] Reading header [+] Detecting header type [+] Executable is a FAT image - searching for right architecture [+] Correct arch is at offset 16384 in the file [+] Opening HBGC.decrypted for writing. [+] Copying the not encrypted start of the file [+] Dumping the decrypted data into the file [+] Copying the not encrypted remainder of the file [+] Setting the LC_ENCRYPTION_INFO->cryptid to 0 at offset 4a90 [+] Closing original file [+] Closing dump file
root# ls FlipswitchCache/ com.apple.audio.hogmode.plist HBGC.decrypted com.apple.tccd/ L65ancd.sock= com.apple.timed.plist L65d.sock= cydia.log MediaCache/ dumpdecrypted.dylib* RestoreFromBackupLock* launchd/ SpringBoard_reboot_flag mobile_assertion_agent.log com.apple.assistant.bundleservicecache.plist其中的HBGC.decrypted就是目标产物，接下来IDA各种斧头水果刀上吧。
首先简单看看xcrun的帮助信息：
$ xcrun -h Usage: xcrun [options] <tool name> ... arguments ... Find and execute the named command line tool from the active developer directory. The active developer directory can be set using `xcode-select`, or via the DEVELOPER_DIR environment variable. See the xcrun and xcode-select manual pages for more information. Options: -h, --help show this help message and exit --version show the xcrun version -v, --verbose show verbose logging output --sdk <sdk name> find the tool for the given SDK name --toolchain <name> find the tool for the given toolchain -l, --log show commands to be executed (with --run) -f, --find only find and print the tool path -r, --run find and execute the tool (the default behavior) -n, --no-cache do not use the lookup cache -k, --kill-cache invalidate all existing cache entries --show-sdk-path show selected SDK install path --show-sdk-version show selected SDK version --show-sdk-platform-path show selected SDK platform path --show-sdk-platform-version show selected SDK platform version
例如上面的Makefile中： GCC_BIN=`xcrun --sdk iphoneos --find gcc`
分解来看：
（1）xcrun --find gcc
$ xcrun --find gcc /Applications/Xcode 5.1.1.app/Contents/Developer/usr/bin/gcc这一步获取了gcc这个tool的路径，设为cmd_tool_path。
（2）xcrun --sdk iphoneos cmd_tool_path
这一步通过路径名获取到了具体的工具程序，这个工具对应iphoneos的SDK，并执行该工具。
（3）GCC_BIN是一条shell命令，对应的就是这个查找和执行工具的过程。
再如： xcrun --sdk iphoneos --show-sdk-path
它的作用就是查找对应于iphoneos SDK的SDK并执行。
$ xcrun --show-sdk-path /Applications/Xcode 5.1.1.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk $ xcrun --sdk iphoneos --show-sdk-path /Applications/Xcode 5.1.1.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.1.sdk
首先看看简单的帮助信息：
$ xcode-select -h Usage: xcode-select [options] Print or change the path to the active developer directory. This directory controls which tools are used for the Xcode command line tools (for example, xcodebuild) as well as the BSD development commands (such as cc and make). Options: -h, --help print this help message and exit -p, --print-path print the path of the active developer directory -s <path>, --switch <path> set the path for the active developer directory -v, --version print the xcode-select version -r, --reset reset to the default command line tools path
/Applications/Xcode 5.1.1.app/Contents/Developer
$ ls BuildStrings gcc ndisasm CpMac gcov-4.2 opendiff DeRez git projectInfo GetFileInfo git-cvsserver resolveLinks ImageUnitAnalyzer git-receive-pack scntool MergePef git-shell sdef MvMac git-upload-archive sdp ResMerger git-upload-pack svn Rez gnumake svnadmin RezDet hdxml2manxml svndumpfilter RezWack headerdoc2html svnlook SetFile ibtool svnrdump SplitForks ibtool3 svnserve TextureAtlas ibtoold svnsync UnRezWack ictool svnversion actool instruments symbols agvtool iprofiler xcodebuild amlint ld xcrun以上只是部分输出。
注：以上是我个人在自己的机子上的砸壳经历，大家要根据自己的实际情况进行，详细请参考：用dumpdecrypted砸壳
《iOS应用逆向工程》学习笔记（六）使用dumpdecrypted砸壳,布布扣,bubuko.com
《iOS应用逆向工程》学习笔记（六）使用dumpdecrypted砸壳
标签：ios逆向工程
原文地址：http://blog.csdn.net/jymn_chen/article/details/38361161
