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From: "wilson at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/96191] aarch64 stack_protect_test canary leak
Date: Tue, 14 Jul 2020 22:30:21 +0000	[thread overview]
Message-ID: <bug-96191-4-C38hr42lPH@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-96191-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96191

--- Comment #3 from Jim Wilson <wilson at gcc dot gnu.org> ---
The location of the canary is not known to the attacker.  You are not supposed
to leak the address of the canary or the value of the canary.  If you leak
either, then an attacker has a chance to restore the canary after clobbering
it.

See the descriptions of the stack_protect_set and stack_protect_test patterns
in gcc/doc/md.texi which make clear that no intermediate values should be
allowed to survive past the end of the pattern.

  parent reply	other threads:[~2020-07-14 22:30 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-14  2:49 [Bug target/96191] New: " wilson at gcc dot gnu.org
2020-07-14  8:22 ` [Bug target/96191] " rsandifo at gcc dot gnu.org
2020-07-14 18:58 ` wilco at gcc dot gnu.org
2020-07-14 22:30 ` wilson at gcc dot gnu.org [this message]
2020-08-05 14:19 ` cvs-commit at gcc dot gnu.org
2020-08-06 18:20 ` cvs-commit at gcc dot gnu.org
2020-08-07 11:15 ` cvs-commit at gcc dot gnu.org
2020-08-07 11:15 ` cvs-commit at gcc dot gnu.org
2020-08-07 11:18 ` cvs-commit at gcc dot gnu.org
2020-08-07 11:18 ` cvs-commit at gcc dot gnu.org
2020-11-17 18:17 ` cvs-commit at gcc dot gnu.org

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