Re: [RFC PATCH] cmdline: Hide "debug" from /proc/cmdline

[Jiri Kosina]

On Wed, 2 Apr 2014, Linus Torvalds wrote:

> > Which doesn't really protect you from tasks that do open()/write()/close()
> > cycle for /dev/kmsg write every 2ms though.
> 
> I don't think we should try to protect against wilful bad behavior
> unless that is shown to be necessary. Yeah, if it turns out that
> systemd really does that just to mess with us, we'd need to extend it,
> but in the absence of proof to the contrary, maybe this simple
> attached patch works?
> 
> TOTALLY UNTESTED. But it really isn't complex.

[ ... snip ... [
@@ -483,6 +484,8 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
 
 	if (!user)
 		return -EBADF;
+	if (!___ratelimit(&user->rs, current->comm))
+		return 0;

I am admittedly rather new to this 'abuse the hell out of kernel 
ringbuffer' thing, but shouldn't we better be limiting the 
devkmsg_writev()?

-- 
Jiri Kosina
SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/