|
Message-ID: <CAGXu5jKPTaomgyBiSFCYJDFqGaVd=sWpXnjHpT-7YDmk1AVVyg@mail.gmail.com> Date: Thu, 6 Dec 2018 10:25:17 -0800 From: Kees Cook <keescook@...omium.org> To: Alexander Popov <alex.popov@...ux.com> Cc: Kernel Hardening <kernel-hardening@...ts.openwall.com>, Jann Horn <jannh@...gle.com>, Andy Lutomirski <luto@...nel.org>, Borislav Petkov <bp@...en8.de>, Thomas Gleixner <tglx@...utronix.de>, Dave Hansen <dave.hansen@...ux.intel.com>, Steven Rostedt <rostedt@...dmis.org>, Peter Zijlstra <peterz@...radead.org>, Masami Hiramatsu <mhiramat@...nel.org>, Florian Weimer <fweimer@...hat.com>, Richard Sandiford <richard.sandiford@....com>, Segher Boessenkool <segher@...nel.crashing.org>, amonakov@...ras.ru, Tycho Andersen <tycho@...ho.ws>, Laura Abbott <labbott@...hat.com>, Mark Rutland <mark.rutland@....com>, Emese Revfy <re.emese@...il.com>, Thomas Garnier <thgarnie@...gle.com>, Ingo Molnar <mingo@...nel.org>, Will Deacon <will.deacon@....com>, Alexei Starovoitov <ast@...nel.org>, Ard Biesheuvel <ard.biesheuvel@...aro.org>, "H. Peter Anvin" <hpa@...or.com>, "David S. Miller" <davem@...emloft.net>, linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>, gcc@....gnu.org, LKML <linux-kernel@...r.kernel.org> Subject: Re: [PATCH v2 1/1] stackleak: Register the 'stackleak_cleanup' pass before the '*free_cfg' pass On Thu, Dec 6, 2018 at 7:13 AM Alexander Popov <alex.popov@...ux.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 '*free_cfg' pass. It's the moment when the stack frame size is > already final, function prologues and epilogues are generated, and the > machine-dependent code transformations are not done. > > [1] https://www.openwall.com/lists/kernel-hardening/2018/11/23/2 > > Reported-by: kbuild test robot <lkp@...el.com> > Signed-off-by: Alexander Popov <alex.popov@...ux.com> Thanks! I've applied this to me tree and I'll send a pull request soon. -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..dbd3746 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 "*free_cfg" > + * pass. It's the moment when the stack frame size is already final, > + * function prologues and epilogues are generated, and the > + * machine-dependent code transformations are not done. > */ > - PASS_INFO(stackleak_cleanup, "reload", 1, PASS_POS_INSERT_AFTER); > + PASS_INFO(stackleak_cleanup, "*free_cfg", 1, PASS_POS_INSERT_BEFORE); > > if (!plugin_default_version_check(version, &gcc_version)) { > error(G_("incompatible gcc/plugin versions")); > -- > 2.7.4 > -- Kees Cook
Powered by blists - more mailing lists
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.