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: <20210903000246.425731d5@oasis.local.home>
Date:   Fri, 3 Sep 2021 00:02:46 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Jiang Jiasheng <jiasheng@...as.ac.cn>
Cc:     mingo@...hat.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] tracing: Add trace_trigger_soft_disabled() in front
 of trace_event_buffer_reserve() in trace_inject_entry()

On Fri,  3 Sep 2021 03:30:34 +0000
Jiang Jiasheng <jiasheng@...as.ac.cn> wrote:

> Directly use trace_event_buffer_reserve() might be unsafe,

How can it be unsafe?

> as we can see from the trace_trigger_soft_disabled() of
> 'include/linux/trace_events.h' that if the value of
> file->flags is 256, the check in the trace_trigger_soft_disabled()
> will be passed but actually shouldn't have.
> Therefore, we suggest that trace_trigger_soft_disabled()
> should be added in front of the trace_event_buffer_reserve()
> in trace_inject_entry().

Do you understand what the trace_inject_entry() does?

I'm not sure it makes sense to "soft disable" it.

> 
> Signed-off-by: Jiang Jiasheng <jiasheng@...as.ac.cn>
> ---
>  kernel/trace/trace_events_inject.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/kernel/trace/trace_events_inject.c b/kernel/trace/trace_events_inject.c
> index c188045..6dfd3cd 100644
> --- a/kernel/trace/trace_events_inject.c
> +++ b/kernel/trace/trace_events_inject.c
> @@ -21,6 +21,8 @@ trace_inject_entry(struct trace_event_file *file, void *rec, int len)
>  	void *entry;
>  
>  	rcu_read_lock_sched();
> +	if (trace_trigger_soft_disabled(file))
> +		return written;

NACK!

The above introduces a major bug. Bonus points if you can figure out
what that is yourself.

-- Steve

>  	entry = trace_event_buffer_reserve(&fbuffer, file, len);
>  	if (entry) {
>  		memcpy(entry, rec, len);

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ