linux-kernel - Re: [tip: x86/asm] x86/asm: Make ASM_CALL_CONSTRAINT conditional on frame pointers

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: <20250308081530.7c7e4f94@pumpkin>
Date: Sat, 8 Mar 2025 08:15:30 +0000
From: David Laight <david.laight.linux@...il.com>
To: Josh Poimboeuf <jpoimboe@...nel.org>
Cc: "H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...nel.org>,
 linux-kernel@...r.kernel.org, tip-bot2 for Josh Poimboeuf
 <tip-bot2@...utronix.de>, linux-tip-commits@...r.kernel.org, "Peter
 Zijlstra (Intel)" <peterz@...radead.org>, Linus Torvalds
 <torvalds@...ux-foundation.org>, Brian Gerst <brgerst@...il.com>,
 x86@...nel.org
Subject: Re: [tip: x86/asm] x86/asm: Make ASM_CALL_CONSTRAINT conditional on
 frame pointers

On Fri, 7 Mar 2025 17:38:14 -0800
Josh Poimboeuf <jpoimboe@...nel.org> wrote:

...
> We hopefully won't need those hacks much longer anyway, as I'll have
> another series to propose removing frame pointers for x86-64.
> 
> x86-32 can keep frame pointers, but doesn't need the constraints.  It's
> not supported for livepatch so it doesn't need to be 100% reliable.
> Worst case, an unwind skips a frame, but the call address still shows up
> on stack trace dumps prepended with '?'.

Doesn't 'user copy hardening' also do stack following?
That needs to find all the stack frames (that have locals) and I think
is is more reliable with frame pointers.

	David