Multiple memory corruption issues and race condition in Goodix gt915 touchscreen driver procfs handler (CVE-2013-4740 CVE-2013-6122)

Release Date: 
November 7, 2013
Affected Projects: 
Advisory ID: 
QCIR-2013-00009-1
Summary: 

Multiple issues have been identified in the Goodix gt915 touchscreen driver for Android. The issues were found in the write handler of the procfs entry created by the driver, which by default is readable and writeable to users without any specific privileges.

CVE-2013-4740:
When processing data written to the procfs file, the Goodix gt915 touchscreen driver is using user space supplied content as length values in subsequent memory manipulation operations without bounds checking. This can lead to multiple memory corruption issues. An application with access to the respective file can use this flaw to, e.g., elevate privileges.

Access Vector: local
Security Risk: high
Vulnerability: CWE-20 (Improper Input Validation)

CVE-2013-6122:
When processing arguments passed to the procfs write handler of the Goodix gt915 touchscreen driver, user space data is copied to a global variable and used without a mutual-exclusion mechanism. The global structure used by the procfs write handler can be accessed concurrently by more than one process. This would allow local attackers to bypass the input validation checks (such as introduced by the fix for CVE-2013-4740). An application with access to the respective file can use this flaw to, e.g., alter the internal state of the handler, bypass security checks, or create a denial-of-service condition.

Access Vector: local
Security Risk: medium
Vulnerability: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

Affected versions
All Android releases from CAF using the Linux kernel from the following heads:

  • jb_3*
  • msm-3.10
Acknowledgement: 

Qualcomm Innovation Center, Inc. (QuIC) thanks Jonathan Salwan of the Sysdream Security Lab for reporting the related issues and working with QuIC to help improve Android device security.

Revisions: 

Initial revision

Contact: 
security-advisory@quicinc.com