From: hpa@zytor.com (H. Peter Anvin)
To: linux-kernel@vger.kernel.org
Subject: Re: short read from /dev/urandom
Date: Sat, 15 Jan 2005 02:34:37 +0000 (UTC) [thread overview]
Message-ID: <cs9vft$412$1@terminus.zytor.com> (raw)
In-Reply-To: 41E833F4.8090800@redhat.com
Followup to: <41E833F4.8090800@redhat.com>
By author: Ulrich Drepper <drepper@redhat.com>
In newsgroup: linux.dev.kernel
>
> The code in question comes from a crypto library which is in wide use
> (http://www.cryptopp.com) and it is using urandom under this assumption.
> I fear there is quite a bit more code like this out there. Changing
> the ABI after the fact is no good and dangerous in this case.
>
> I know this is making the device special, but I really think the
> no-short-reads property should be perserved for urandom.
>
Does *anything* have it, including files?
I think read() always has the option of returning a short read on
signal delivery.
What urandom has is a no-block guarantee, i.e. the behaviour should be
identical in the presense of the O_NONBLOCK flag, and select/poll
should always indicate that data can be read.
-hpa
next prev parent reply other threads:[~2005-01-15 2:35 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-01-14 4:54 short read from /dev/urandom Ulrich Drepper
2005-01-14 5:56 ` David Wagner
2005-01-14 6:54 ` Ulrich Drepper
2005-01-14 19:55 ` David Wagner
2005-01-14 19:10 ` Theodore Ts'o
2005-01-14 21:04 ` Ulrich Drepper
2005-01-14 23:21 ` Theodore Ts'o
2005-01-15 2:36 ` H. Peter Anvin
2005-01-16 2:51 ` Matt Mackall
2005-01-16 3:18 ` H. Peter Anvin
2005-01-15 2:34 ` H. Peter Anvin [this message]
2005-01-19 15:48 ` Pavel Machek
2005-01-16 2:44 ` Matt Mackall
2005-01-16 3:58 ` Ulrich Drepper
2005-01-16 4:58 ` Matt Mackall
2005-01-16 13:23 ` Andries Brouwer
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