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Re: RFC: stack/heap collision vulnerability and mitigation with GCC

From: Andreas Schwab <schwab at suse dot de>
To: "Richard Earnshaw \(lists\)" <Richard dot Earnshaw at arm dot com>
Cc: Wilco Dijkstra <Wilco dot Dijkstra at arm dot com>, Jeff Law <law at redhat dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>, nd <nd at arm dot com>
Date: Wed, 21 Jun 2017 10:44:44 +0200
Subject: Re: RFC: stack/heap collision vulnerability and mitigation with GCC
Authentication-results: sourceware.org; auth=none
References: <AM5PR0802MB2610C07342688AA9A63FB3BA83C50@AM5PR0802MB2610.eurprd08.prod.outlook.com> <71e54fa7-0763-fe20-4720-40574f46f2e6@arm.com>

On Jun 21 2017, "Richard Earnshaw (lists)" <Richard.Earnshaw@arm.com> wrote:

> A mere 256 bytes for the caller would permit 32 x 8byte arguments on the
> stack which, with at least 8 parameters passed in registers, would allow
> for calls with 40 parameters.  There can't be many in that space.  Any
> function making calls with more than that might need additional probes,
> but that's going to be exceedingly rare.

With passing structures by value you can have arbitrary large
parameters.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

Follow-Ups:
- Re: RFC: stack/heap collision vulnerability and mitigation with GCC
  - From: Richard Earnshaw (lists)

References:
- Re: RFC: stack/heap collision vulnerability and mitigation with GCC
  - From: Wilco Dijkstra
- Re: RFC: stack/heap collision vulnerability and mitigation with GCC
  - From: Richard Earnshaw (lists)

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