Qualcomm acdb audio buffer overflow

The acdb audio driver provides an ioctl system call interface to user space clients for communication. When processing arguments passed to the ioctl handler, a user space supplied size is used to copy as many bytes from user space to a local stack buffer without proper bounds checking. An application with access to the /dev/msm_acdb device file (audio or system group) can use this flaw to, e.g., elevate privileges. QCIR-2013-00002-1