From: Robert Love <rml@novell.com>
To: Ron Peterson <rpeterso@mtholyoke.edu>
Cc: linux-kernel@vger.kernel.org
Subject: Re: /dev/random vs. /dev/urandom
Date: Fri, 07 Jan 2005 14:40:43 -0500 [thread overview]
Message-ID: <1105126843.9311.41.camel@betsy.boston.ximian.com> (raw)
In-Reply-To: <20050107190536.GA14205@mtholyoke.edu>
On Fri, 2005-01-07 at 14:05 -0500, Ron Peterson wrote:
> read( fd, dat, RAND_LEN );
> for( i = 0; i < RAND_LEN; i++ ) {
> dat[i] = (dat[i] & 0x07) + '0';
> }
Your problem is probably because read() need not actually read RAND_LEN
bytes. Particularly with /dev/random, since it will only return bytes
up to the entropy estimate. But you assume it read RAND_LEN, when those
are unread. And possibly zero. So that is probably your bug.
The AND makes zero sense, either.
Just use dd(1).
Robert Love
next prev parent reply other threads:[~2005-01-07 19:49 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-01-07 19:05 /dev/random vs. /dev/urandom Ron Peterson
2005-01-07 19:16 ` Paulo Marques
2005-01-07 19:24 ` Chris Friesen
2005-01-07 19:26 ` Florian Weimer
2005-01-07 19:27 ` linux-os
2005-01-07 19:40 ` Robert Love [this message]
2005-01-07 20:50 ` Ron Peterson
2005-01-07 21:39 ` Andries Brouwer
2005-01-07 22:39 ` linux-os
2005-01-07 17:55 ` Michal Schmidt
2005-01-07 23:29 ` Andries Brouwer
2005-01-08 17:34 ` Patrick J. LoPresti
2005-01-10 12:41 ` linux-os
2005-01-10 13:03 ` Paulo Marques
2005-01-10 14:39 ` Felipe Alfaro Solana
2005-01-10 15:13 ` Patrick J. LoPresti
2005-01-10 19:24 ` David Schwartz
2005-01-11 14:38 ` Andrea Arcangeli
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