Re: [PATCH] KEYS: prevent NULL pointer dereference in find_asymmetric_key()

From: Roman Smirnov <r.smirnov@omp.ru>
To: Jarkko Sakkinen <jarkko@kernel.org>,
	David Howells <dhowells@redhat.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	"David S. Miller" <davem@davemloft.net>,
	Andrew Zaborowski <andrew.zaborowski@intel.com>
Cc: "keyrings@vger.kernel.org" <keyrings@vger.kernel.org>,
	"linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"lvc-project@linuxtesting.org" <lvc-project@linuxtesting.org>,
	"Sergey Shtylyov" <s.shtylyov@omp.ru>
Subject: Re: [PATCH] KEYS: prevent NULL pointer dereference in find_asymmetric_key()
Date: Tue, 19 Mar 2024 14:44:35 +0000	[thread overview]
Message-ID: <b5f21d1175c142efb52e68a24bc4165a@omp.ru> (raw)
In-Reply-To: <CZX9T3TU6YU0.3JE9M7M3ENUE0@kernel.org>

On Tue, 19 Mar 2024 01:39:00 +0200 Jarkko Sakkinen wrote:
> On Fri Mar 15, 2024 at 12:33 PM EET, Roman Smirnov wrote:
> > With the current code, in case all NULLs are passed in id_{0,1,2},
> 
> "current code" is not unambigious reference of any part of the kernel
> tree. Please just write down the function name instead.
> 
> > the kernel will first print out a WARNING and then have an oops
> > because id_2 gets dereferenced anyway.
> 
> Would be more exact":
> 
> s/print out a WARNING/emit WARN/

Okay, I'll prepare a second version of the patch.

> > Note that WARN_ON() is also considered harmful by Greg Kroah-
> > Hartman since it causes the Android kernels to panic as they
> > get booted with the panic_on_warn option.
> 
> Despite full respect to Greg, and agreeing what he had said about
> the topic (which you are lacking lore link meaning that in all
> cases the current description is incomplete), the only thing that
> should be documented should be that since WARN_ON() can emit
> panic when panic_on_warn is set in the *kernel command-line*
> (not "option") this condition should be relaxed.

Here's a link to the discussion:
https://lore.kernel.org/all/2024011213-situated-augmented-64a4@gregkh/
From the context, I thought WARN_ON() would be better removed.

> >
> > Found by Linux Verification Center (linuxtesting.org) with Svace.
> 
> I'm not sure if this should be part of the commit message.

I have already submitted patches with this line, some have been
accepted. It is important for the Linux Verification Center to mark
patches as closing issues found with Svace.

> >
> > Fixes: 7d30198ee24f ("keys: X.509 public key issuer lookup without AKID")
> > Suggested-by: Sergey Shtylyov <s.shtylyov@omp.ru>
> 
> Should be reported-by.

The suggested-by tag belongs to Sergey because he suggested the fix,
subject/description of the patch. The tag reported-by belongs to
Svace tool.

Thank you for the reply.