linux-kernel - Re: [PATCH] tracing/user_events: Don't use %pK through printk

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-Id: <20250219173652.183b22ff533301c5206b9743@kernel.org>
Date: Wed, 19 Feb 2025 17:36:52 +0900
From: Masami Hiramatsu (Google) <mhiramat@...nel.org>
To: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
Cc: Steven Rostedt <rostedt@...dmis.org>, Mathieu Desnoyers
 <mathieu.desnoyers@...icios.com>, linux-kernel@...r.kernel.org,
 linux-trace-kernel@...r.kernel.org
Subject: Re: [PATCH] tracing/user_events: Don't use %pK through printk

On Wed, 19 Feb 2025 08:14:34 +0100
Thomas Weißschuh <thomas.weissschuh@...utronix.de> wrote:

> On Wed, Feb 19, 2025 at 09:10:23AM +0900, Masami Hiramatsu wrote:
> > On Mon, 17 Feb 2025 14:16:12 +0100
> > Thomas Weißschuh <thomas.weissschuh@...utronix.de> wrote:
> > 
> > > Restricted pointers ("%pK") are not meant to be used through printk().
> > > It can unintentionally expose security sensitive, raw pointer values.
> > > 
> > > Use regular pointer formatting instead.
> > > 
> > > Link: https://lore.kernel.org/lkml/20250113171731-dc10e3c1-da64-4af0-b767-7c7070468023@linutronix.de/
> > 
> > This is only for the kernel pointer, but the "uaddr" below means it
> > has a user space address. So I think this does not need to be applied.
> 
> "uaddr" is formatted with %llx, which is fine.
> "%pK" is used for mm->mm, which is a kernel pointer.

Oops, I misread it. OK. looks good to me.

Acked-by: Masami Hiramatsu (Google) <mhiramat@...nel.org>


Thank you,

> 
> > Thank you,
> > 
> > > Signed-off-by: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
> > > ---
> > >  kernel/trace/trace_events_user.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c
> > > index 97325fbd62836f4fb477c4a2b2936eff544291ec..3effc6fce20e65a8077de5221eb69db04fb1a775 100644
> > > --- a/kernel/trace/trace_events_user.c
> > > +++ b/kernel/trace/trace_events_user.c
> > > @@ -455,7 +455,7 @@ static void user_event_enabler_fault_fixup(struct work_struct *work)
> > >  	if (ret && ret != -ENOENT) {
> > >  		struct user_event *user = enabler->event;
> > >  
> > > -		pr_warn("user_events: Fault for mm: 0x%pK @ 0x%llx event: %s\n",
> > > +		pr_warn("user_events: Fault for mm: 0x%p @ 0x%llx event: %s\n",
> > >  			mm->mm, (unsigned long long)uaddr, EVENT_NAME(user));
> > >  	}
> > >  
> > > 
> > > ---
> > > base-commit: 0ad2507d5d93f39619fc42372c347d6006b64319
> > > change-id: 20250217-restricted-pointers-trace-a0fb12707ac6
> > > 
> > > Best regards,
> > > -- 
> > > Thomas Weißschuh <thomas.weissschuh@...utronix.de>


-- 
Masami Hiramatsu (Google) <mhiramat@...nel.org>