linux-kernel - Re: [patch V3 04/23] kprobes: Prevent probes in .noinstr.text section

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 25 Mar 2020 22:39:46 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     LKML <linux-kernel@...r.kernel.org>, x86@...nel.org,
        Paul McKenney <paulmck@...nel.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        "Joel Fernandes \(Google\)" <joel@...lfernandes.org>,
        "Steven Rostedt \(VMware\)" <rostedt@...dmis.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Frederic Weisbecker <frederic@...nel.org>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Brian Gerst <brgerst@...il.com>,
        Juergen Gross <jgross@...e.com>,
        Alexandre Chartre <alexandre.chartre@...cle.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Tom Lendacky <thomas.lendacky@....com>,
        Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org
Subject: Re: [patch V3 04/23] kprobes: Prevent probes in .noinstr.text
 section

On Tue, 24 Mar 2020 10:47:30 +0100
Thomas Gleixner <tglx@...utronix.de> wrote:

> Masami Hiramatsu <mhiramat@...nel.org> writes:
> > On Mon, 23 Mar 2020 17:03:24 +0100
> > Thomas Gleixner <tglx@...utronix.de> wrote:
> >> > @@ -2212,6 +2212,10 @@ static int __init populate_kprobe_blacklist(unsigned long *start,
> >> >  	ret = kprobe_add_area_blacklist((unsigned long)__kprobes_text_start,
> >> >  					(unsigned long)__kprobes_text_end);
> >> >  
> >> > +	/* Symbols in noinstr section are blacklisted */
> >> > +	ret = kprobe_add_area_blacklist((unsigned long)__noinstr_text_start,
> >> > +					(unsigned long)__noinstr_text_end);
> >> > +
> >> >  	return ret ? : arch_populate_kprobe_blacklist();
> >> >  }
> >> 
> >> So that extra function is not required when adding that, right?
> >
> > That's right :)
> >
> >> 
> >> >> +/* Functions in .noinstr.text must not be probed */
> >> >> +static bool within_noinstr_text(unsigned long addr)
> >> >> +{
> >> >> +	/* FIXME: Handle module .noinstr.text */
> >
> > And this reminds me that the module .kprobes.text is not handled yet :(.
> 
> Correct. Any idea how to do that with a simple oneliner like the above?

Hmm, we can store the .kprobes.text and .noinstr.text section info in the struct
module and register it in module callback. But before that, I have to introduce
a remove function. Currently, the blacklist can only add symbols. So that will
not be a oneliner.

Let me try.

Thank you,


-- 
Masami Hiramatsu <mhiramat@...nel.org>