Messages in this thread | | | From | "Roberts, William C" <> | Subject | RE: [PATCH] printk: introduce kptr_restrict level 3 | Date | Thu, 6 Oct 2016 13:47:47 +0000 |
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> -----Original Message----- > From: Christoph Hellwig [mailto:hch@infradead.org] > Sent: Thursday, October 6, 2016 9:32 AM > To: Roberts, William C <william.c.roberts@intel.com> > Cc: kernel-hardening@lists.openwall.com; corbet@lwn.net; linux- > doc@vger.kernel.org; linux-kernel@vger.kernel.org > Subject: Re: [PATCH] printk: introduce kptr_restrict level 3 > > On Wed, Oct 05, 2016 at 02:04:46PM -0400, william.c.roberts@intel.com wrote: > > From: William Roberts <william.c.roberts@intel.com> > > > > Some out-of-tree modules do not use %pK and just use %p, as it's the > > common C paradigm for printing pointers. Because of this, > > kptr_restrict has no affect on the output and thus, no way to contain > > the kernel address leak. > > So what? We a) don't care about out of tree modules and b) you could just triviall > fix them up if you care.
Out of tree modules still affect core kernel security. I would also bet money, that somewhere In-tree someone has put a %p when they wanted a %pK. So this method is just quite error prone. We currently have a blacklist approach versus whitelist.
> > No need to bloat the kernel with crap like this.
It's unconstructive comments like this that do the whole community harm. Notice how responses from Kees Cook were aimed at finding a different solution to the problem and were very constructive. As far as "bloating" goes, it really didn't change a whole lot, most of it was moved lines, and adds maybe a few lines of code.
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