From: Kees Cook <keescook@chromium.org>
To: Alexander Popov <alex.popov@linux.com>
Cc: Kernel Hardening <kernel-hardening@lists.openwall.com>,
Jann Horn <jannh@google.com>, Andy Lutomirski <luto@kernel.org>,
Borislav Petkov <bp@alien8.de>,
Thomas Gleixner <tglx@linutronix.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Steven Rostedt <rostedt@goodmis.org>,
Peter Zijlstra <peterz@infradead.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Florian Weimer <fweimer@redhat.com>,
Richard Sandiford <richard.sandiford@arm.com>,
Segher Boessenkool <segher@kernel.crashing.org>,
amonakov@ispras.ru, Tycho Andersen <tycho@tycho.ws>,
Laura Abbott <labbott@redhat.com>,
Mark Rutland <mark.rutland@arm.com>,
Emese Revfy <re.emese@gmail.com>,
Thomas Garnier <thgarnie@google.com>,
Ingo Molnar <mingo@kernel.org>,
Will Deacon <will.deacon@arm.com>,
Alexei Starovoitov <ast@kernel.org>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
"H. Peter Anvin" <hpa@zytor.com>,
"David S. Miller" <davem@davemloft.net>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
gcc@gcc.gnu.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/1] stackleak: Register the 'stackleak_cleanup' pass before the 'mach' pass
Date: Fri, 30 Nov 2018 17:18:00 -0000 [thread overview]
Message-ID: <CAGXu5jJ7LmHRJJxtH2HD4XEu5hPLtAe=koJbaCmqF9qoSw=sVw@mail.gmail.com> (raw)
In-Reply-To: <1543583987-27948-1-git-send-email-alex.popov@linux.com>
On Fri, Nov 30, 2018 at 5:20 AM Alexander Popov <alex.popov@linux.com> wrote:
>
> Currently the 'stackleak_cleanup' pass deleting a CALL insn is executed
> after the 'reload' pass. That allows gcc to do some weird optimization in
> function prologues and epilogues, which are generated later [1].
>
> Let's avoid that by registering the 'stackleak_cleanup' pass before
> the 'mach' pass, which performs the machine dependent code transformations.
> It's the moment when the stack frame size is final and function prologues
> and epilogues are already generated.
>
> [1] https://www.openwall.com/lists/kernel-hardening/2018/11/23/2
>
> Reported-by: kbuild test robot <lkp@intel.com>
> Signed-off-by: Alexander Popov <alex.popov@linux.com>
Thanks, applied!
-Kees
> ---
> scripts/gcc-plugins/stackleak_plugin.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/scripts/gcc-plugins/stackleak_plugin.c b/scripts/gcc-plugins/stackleak_plugin.c
> index 2f48da9..6f41b32 100644
> --- a/scripts/gcc-plugins/stackleak_plugin.c
> +++ b/scripts/gcc-plugins/stackleak_plugin.c
> @@ -363,10 +363,12 @@ __visible int plugin_init(struct plugin_name_args *plugin_info,
> PASS_POS_INSERT_BEFORE);
>
> /*
> - * The stackleak_cleanup pass should be executed after the
> - * "reload" pass, when the stack frame size is final.
> + * The stackleak_cleanup pass should be executed before the "mach"
> + * pass, which performs the machine dependent code transformations.
> + * It's the moment when the stack frame size is already final and
> + * function prologues and epilogues are generated.
> */
> - PASS_INFO(stackleak_cleanup, "reload", 1, PASS_POS_INSERT_AFTER);
> + PASS_INFO(stackleak_cleanup, "mach", 1, PASS_POS_INSERT_BEFORE);
>
> if (!plugin_default_version_check(version, &gcc_version)) {
> error(G_("incompatible gcc/plugin versions"));
> --
> 2.7.4
>
--
Kees Cook
next parent reply other threads:[~2018-11-30 17:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1543583987-27948-1-git-send-email-alex.popov@linux.com>
2018-11-30 17:18 ` Kees Cook [this message]
2018-11-30 19:09 ` Kees Cook
2018-11-30 22:40 ` Alexander Popov
2018-12-03 18:25 ` Alexander Popov
2018-12-06 15:10 ` Alexander Popov
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