linux-kernel - Re: [PATCH v6 1/5] random: Blocking API for accessing nonblocking

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: <2931045.EGfWxfUOa7@tauon>
Date:	Mon, 18 May 2015 15:26:13 +0200
From:	Stephan Mueller <smueller@...onox.de>
To:	Herbert Xu <herbert@...dor.apana.org.au>
Cc:	pebolle@...cali.nl, andreas.steffen@...ongswan.org, tytso@....edu,
	sandyinchina@...il.com, linux-kernel@...r.kernel.org,
	linux-crypto@...r.kernel.org
Subject: Re: [PATCH v6 1/5] random: Blocking API for accessing nonblocking_pool

Am Montag, 18. Mai 2015, 15:07:10 schrieb Stephan Mueller:

Hi Herbert,

>>
>>You can simplify this further and get rid of buf/nbytes.  All
>>we need to know is whether the pool is ready.  Everything else
>>can come from private.
>
>So, the async function is now just a notification of the caller. Sounds good
>with me.
>

I am just running into an interesting problem with a missing cancel operation: 
a caller instantiates a DRBG handle and invokes the seeding operation. The 
nonblocking_pool is not initialized. Therefore, the callback is put onto the 
list for being processed later.

Now, the caller releases the DRBG handle *before* the callback is triggered.

The callback is triggered with a pointer that is invalid, but the pointer is 
non-NULL. Therefore, I am not sure how to validate the pointer in the callback 
function.

I would think that there is no other way than to add a cancel API call that 
allows removing a list entry from the wait list.

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