linux-kernel - Re: [PATCH v2] KEYS: prevent NULL pointer dereference in find_asymmetric

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] [thread-next>] [day] [month] [year] [list]

Message-Id: <D43HG3PEBR4I.2INNPVZIT19ZZ@kernel.org>
Date: Wed, 11 Sep 2024 16:18:04 +0300
From: "Jarkko Sakkinen" <jarkko@...nel.org>
To: "Sergey Shtylyov" <s.shtylyov@....ru>, "Roman Smirnov"
 <r.smirnov@....ru>, "David Howells" <dhowells@...hat.com>, "Herbert Xu"
 <herbert@...dor.apana.org.au>, "David S. Miller" <davem@...emloft.net>,
 "Andrew Zaborowski" <andrew.zaborowski@...el.com>
Cc: <keyrings@...r.kernel.org>, <linux-crypto@...r.kernel.org>,
 <linux-kernel@...r.kernel.org>, <lvc-project@...uxtesting.org>
Subject: Re: [PATCH v2] KEYS: prevent NULL pointer dereference in
 find_asymmetric_key()

On Tue Sep 10, 2024 at 8:38 PM EEST, Sergey Shtylyov wrote:
> On 9/10/24 4:38 PM, Jarkko Sakkinen wrote:
> [...]
>
> >> In find_asymmetric_key(), if all NULLs are passed in id_{0,1,2} parameters
> >> the kernel will first emit WARN and then have an oops because id_2 gets
> >> dereferenced anyway.
> >>
> >> Found by Linux Verification Center (linuxtesting.org) with Svace static
> >> analysis tool.
> > 
> > Weird, I recall that I've either sent a patch to address the same site
> > OR have commented a patch with similar reasoning. Well, it does not
> > matter, I think it this makes sense to me.
> > 
> > You could further add to the motivation that given the panic_on_warn
> > kernel command-line parameter, it is for the best limit the scope and
> > use of the WARN-macro.
>
>    I don't understand what you mean -- this version of the patch keeps
> the WARN_ON() call, it just moves that call, so that the duplicate id_{0,1,2}
> checks are avoided...

I overlooked the code change (my bad sorry). Here's a better version of
the first paragraph:

"find_asymmetric_keys() has nullity checks of id_0 and id_1 but ignores
validation for id_2. Check nullity also for id_2."

Yep, and it changes no situation with WARN_ON() macro for better or
worse. It would logically separate issue to discuss and address so
as far as I'm concerned, with this clarification I think the change
makes sense to me.

BR, Jarkko