Re: [PATCH v3 1/3] SROP Mitigation: Architecture independent code for signal cookies

From: Andy Lutomirski
Date: Tue Mar 08 2016 - 15:59:32 EST

On Tue, Mar 8, 2016 at 12:47 PM, Scott Bauer <sbauer@xxxxxxxxxxxx> wrote:
> This patch adds a per-process secret to the task struct which
> will be used during signal delivery and during a sigreturn.
> Also, logic is added in signal.c to generate, place, extract,
> clear and verify the signal cookie.

Potentially silly question: it's been a while since I read the SROP
paper, but would the technique be effectively mitigated if sigreturn
were to zero out the whole signal frame before returning to user mode?