From: Rich Felker <dalias@libc.org>
To: musl@lists.openwall.com
Subject: Re: magic constants in some startup code
Date: Fri, 31 Oct 2014 12:09:13 -0400 [thread overview]
Message-ID: <20141031160913.GC22465@brightrain.aerifal.cx> (raw)
In-Reply-To: <8B3E5DDE-2691-4377-8934-362ACC7BEA69@cognitive-electronics.com>
On Fri, Oct 31, 2014 at 10:31:45AM -0400, Richard Gorton wrote:
> Thank you (and a follow up question) - what code looks at this
> canary? It is assigned to pthread_self()->canary, but I do not see
> any code inside musl itself that checks that value? A work in
> progress? Or does other code check this value?
It's part of the stack-protector feature at the compiler level. gcc,
clang, and any other compilers that implement this feature generate
code to read the canary at the start of a function protected by stack
protector, store it between the saved return address and local
buffers, and check that it hasn't been clobbered before returning.
Rich
next prev parent reply other threads:[~2014-10-31 16:09 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-31 13:31 Richard Gorton
2014-10-31 14:18 ` Rich Felker
2014-10-31 14:31 ` Richard Gorton
2014-10-31 16:09 ` Rich Felker [this message]
2014-10-31 20:19 ` Andy Lutomirski
2014-10-31 21:05 ` Rich Felker
2014-10-31 21:29 ` Andy Lutomirski
2014-10-31 21:39 ` Rich Felker
2014-10-31 22:27 ` Andy Lutomirski
2014-10-31 23:14 ` Rich Felker
2014-11-02 17:17 ` Szabolcs Nagy
2014-11-02 19:10 ` Andy Lutomirski
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