linux-kernel - Re: [PATCH] random: fix 32MB+ reads from /dev/urandom

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: <20140723202641.GF6673@thunk.org>
Date:	Wed, 23 Jul 2014 16:26:41 -0400
From:	Theodore Ts'o <tytso@....edu>
To:	Alexey Dobriyan <adobriyan@...il.com>
Cc:	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
	acab@...italfuture.it, stable@...nel.org
Subject: Re: [PATCH] random: fix 32MB+ reads from /dev/urandom

I don't think this patch is worthwhile.  There is no legitimate reason
to be using such large reads like this, and read(2) is always allowed
to return a short read (for example, if a signal comes in while the
read is happening).  The only difference is that we are now guaranteed
to return a short-read if you try to read more than 32MB.  Given that
there is no valid reason to ask for more than 256 or maybe 512 bytes
at a time, I'm not particularly worried about this.

If you really care, you can ask dd keep reading after a short read by
using "iflag=fullblock".  

						- Ted
--
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/