Local privilege escalation via Trusty buffer race

Out-of-bounds write in Google Android's Trusty component allows local users with System privileges to gain higher privileges through a race. The trusty_dputc function increments a shared line-buffer index before checking its 128-byte bound, so concurrent debug-character calls can advance the index and write beyond the buffer. Exploitation requires local System execution privileges on an affected Pixel-family device and no user interaction; the published impact is privilege escalation.