Google Online Security Blog: Hardening the media stack

Hardening the media stack

5 май 2016 г.

Posted by Dan Austin and Jeff Vander Stoep, Android Security team[Cross-posted from the Android Developers Blog]rewardsecurity bulletins

Prevention: Stop bugs from becoming vulnerabilities

Containment: Protect the system by de-privileging and isolating components that handle untrusted content

Preventioninteger overflowsUBSanparseChunkMPEG4ExtractorSIZE_MAXsizechunk_sizesizechunk_sizesizememcpysizechunk_sizesizeProject Zero

Figure 1.sizer6chunk_sizer7r0sizebuffersizer0sizer0r6sizer7chunk_sizer5r0r0r7r0r7CCr3r3bufferadd

Figure 2. Containment

parsing code moved into unprivileged sandboxes that have few or no permissions

components that require sensitive permissions moved into separate sandboxes that only grant access to the specific resources the component needs. For example, only the cameraserver may access the camera, only the audioserver may access Bluetooth, and only the drmserver may access DRM resources.