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Re: ARM per-thread stack protector
- From: Roland McGrath <roland at hack dot frob dot com>
- To: Will Newton <will dot newton at linaro dot org>
- Cc: libc-ports at sourceware dot org
- Date: Fri, 19 Jul 2013 14:41:13 -0700 (PDT)
- Subject: Re: ARM per-thread stack protector
- References: <CANu=Dmg2m0Kq4AieVnwXTKX8axuuJHv8pagaLxebeV+i9ctv4g at mail dot gmail dot com>
No machine has a per-thread canary value. Using one would break
user-implemented stack-switching schemes.
Some machines store the global canary value in every thread's TCB for the
sole reason that it's cheaper to access a field in the TCB than to access a
global variable. I don't think that's the case on ARM.