public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "ardb at kernel dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/102926] TLS register value is spilled to the stack instead of reloaded from the system register
Date: Mon, 25 Oct 2021 12:03:58 +0000	[thread overview]
Message-ID: <bug-102926-4-OVG0xDBPBv@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-102926-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102926

--- Comment #3 from Ard Biesheuvel <ardb at kernel dot org> ---
(In reply to Andrew Pinski from comment #1)
> I don't think it is a security risk really because all spills then can be
> considered security risks.

I would argue that there is no consensus on that. In fact, there is elaborate
handling of the stack canary in the ARM backend, not only to prevent spilling
of the stack canary address or value, but even to ensure that the value is
cleared from all registers that carried it while performing the test or the
set.

In any case, regardless of whether this is a security issue or not (when/if my
TLS stack protector changes get accepted), spilling the TLS register value is
definitely unnecessary.

  parent reply	other threads:[~2021-10-25 12:03 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-25 11:35 [Bug target/102926] New: " ardb at kernel dot org
2021-10-25 11:50 ` [Bug target/102926] " pinskia at gcc dot gnu.org
2021-10-25 12:02 ` rguenth at gcc dot gnu.org
2021-10-25 12:03 ` ardb at kernel dot org [this message]
2021-10-25 12:12 ` pinskia at gcc dot gnu.org
2021-10-25 14:46 ` ardb at kernel dot org
2021-10-25 15:24 ` rsandifo at gcc dot gnu.org

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=bug-102926-4-OVG0xDBPBv@http.gcc.gnu.org/bugzilla/ \
    --to=gcc-bugzilla@gcc.gnu.org \
    --cc=gcc-bugs@gcc.gnu.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).