linux-kernel - Re: [PATCH v4 04/10] x86/traps: Allow custom fixups in handle

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <202502241058.BF06AF37C@keescook>
Date: Mon, 24 Feb 2025 10:59:21 -0800
From: Kees Cook <kees@...nel.org>
To: Peter Zijlstra <peterz@...radead.org>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org, alyssa.milburn@...el.com,
	scott.d.constable@...el.com, joao@...rdrivepizza.com,
	andrew.cooper3@...rix.com, jpoimboe@...nel.org,
	jose.marchesi@...cle.com, hjl.tools@...il.com,
	ndesaulniers@...gle.com, samitolvanen@...gle.com, nathan@...nel.org,
	ojeda@...nel.org, alexei.starovoitov@...il.com, mhiramat@...nel.org,
	jmill@....edu
Subject: Re: [PATCH v4 04/10] x86/traps: Allow custom fixups in handle_bug()

On Mon, Feb 24, 2025 at 01:37:07PM +0100, Peter Zijlstra wrote:
> The normal fixup in handle_bug() is simply continuing at the next
> instruction. However upcomming patches make this the wrong thing, so
> allow handlers (specifically handle_cfi_failure()) to over-ride
> regs->ip.
> 
> The callchain is such that the fixup needs to be done before it is
> determined if the exception is fatal, as such, revert any changes in
> that case.
> 
> Additinoally, have handle_cfi_failure() remember the regs->ip value it

typo above, if you want to tweak that in your tree.

> starts with for reporting.
> 
> Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>

Thanks for the added comment, my future brain will appreciate it. :)

Reviewed-by: Kees Cook <kees@...nel.org>

-- 
Kees Cook