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Re: pgcrypto seeding problem when ssl=on

From: Noah Misch <noah(at)leadboat(dot)com>
To: Marko Kreen <markokr(at)gmail(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>,Postgres Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: pgcrypto seeding problem when ssl=on
Date: 2013-01-14 13:00:42
Message-ID: 20130114130042.GB26919@tornado.leadboat.com (view raw or flat)
Thread:
Lists: pgsql-hackers
On Mon, Jan 14, 2013 at 02:21:00PM +0200, Marko Kreen wrote:
> Note: reading from /dev/urandom does not affect /dev/random.

Reading from /dev/urandom drains the pool that serves /dev/random:

$ cat /proc/sys/kernel/random/entropy_avail 
3596
$ dd iflag=nonblock bs=100 count=1 if=/dev/random of=/dev/null
1+0 records in
1+0 records out
100 bytes (100 B) copied, 0.000174798 s, 572 kB/s
$ cat /proc/sys/kernel/random/entropy_avail 
2839
$ head -c10000000 /dev/urandom >/dev/null
$ cat /proc/sys/kernel/random/entropy_avail 
212
$ dd iflag=nonblock bs=100 count=1 if=/dev/random of=/dev/null
0+1 records in
0+1 records out
38 bytes (38 B) copied, 0.000101439 s, 375 kB/s


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Next:From: Boszormenyi ZoltanDate: 2013-01-14 13:18:18
Subject: Re: Proposal for Allow postgresql.conf values to be changed via SQL [review]
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