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From: Robert Finch <robfi680@gmail.com>
Newsgroups: comp.arch
Subject: Constant Stack Canaries
Date: Sun, 30 Mar 2025 08:16:52 -0400
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Just got to thinking about stack canaries. I was going to have a special 
purpose register holding the canary value for testing while the program 
was running. But I just realized today that it may not be needed. Canary 
values could be handled by the program loader as constants, eliminating 
the need for a register. Since the value is not changing while the 
program is running, it could easily be a constant. This may require a 
fixup record handled by the assembler / linker to indicate to the loader 
to place a canary value.

Prolog code would just store an immediate to the stack. On return a TRAP 
instruction could check for the immediate value and trap if not present.
But the process seems to require assembler / linker support.