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From: "i at maskray dot me" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/104816] -fcf-protection=branch should generate endbr
 instead of notrack jumps
Date: Thu, 18 Jan 2024 09:06:02 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D104816

Fangrui Song <i at maskray dot me> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |i at maskray dot me

--- Comment #13 from Fangrui Song <i at maskray dot me> ---
I created https://gcc.gnu.org/pipermail/gcc-patches/2024-January/643303.html
before I realized that there is a trade-off between two modes.

* (current default, -mno-cet-switch) NOTRACK indirect jump + case handlers
without ENDBR, GCC -mno-cet-switch. Vulnerable to unconstrained indirect ju=
mp
and Branch Target Injection.
* (-mcet-switch) tracked indirect jump + case handlers with ENDBR. Increases
the number of gadgets. Whether they can be usefully exploited depends on the
program.

It seems that the majority of the opinions so far are about the concern of
NOTRACK, so enabling -mcet-switch by default perhaps still makes sense.
-fno-jump-tables isn't a bad choice if users are really concerned about the
gadgets...=