Re: [patch] printk from userspace

H. Peter Anvin
2002-08-14T03:57:03Z

Benjamin LaHaise wrote:
> On Tue, Aug 13, 2002 at 08:18:18PM -0700, Andrew Morton wrote:
>
>>The patch allows userspace to issue printk's, via sys_syslog():
>
>
> This is an incredibly bad idea. It has security hole written all over it.
> Any user can now spam the kernel's log ringbuffer and overrun potentially
> important messages.
>

First of all, only CAP_SYS_ADMIN. As far as spamming the ring buffer,
that's trivial to do today by just sending a bunch of bad network
packets, or attaching a USB CD-ROM without a disc in the drive (yes,
really... on my wife's laptop it was so bad that unless she unplugged
the CD-ROM syslogd was eating her system alive), or...

-hpa