X-Recipient: archive-cygwin AT delorie DOT com
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 7479B385842F
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cygwin.com;
	s=default; t=1706313089;
	bh=xM6mYOFEIa64Y46/5dCA8tR5JdNqPC2+QAD9rmGG02Q=;
	h=Date:To:Cc:Subject:List-Id:List-Unsubscribe:List-Archive:
	 List-Post:List-Help:List-Subscribe:From:Reply-To:From;
	b=ZD57CGlbvRZ5ng/KTERNkcRjwhs89rwV2ekCJxr18ipEdnFv4qn4DL5MfQyi7X+Xg
	 V4evj78L8KuM+8Lwv25f431ec0RS30j/jrxJ2GZ7tJ3KoIIjN/gbnP2U7Z4K9Ph417
	 kCZMBvVm3IaS3Fg3OYAmZc4R48PFA2OnQZiE0/+I=
X-Original-To: cygwin AT cygwin DOT com
Delivered-To: cygwin AT cygwin DOT com
DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 2A6F13858D33
ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 2A6F13858D33
ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1706313028; cv=none;
 b=cG55DQsiZuwF6jbyRqcYFZVuafNozlZf4AlpCiYQlOwH7biz8kBDYqZ1dSlynjCmLHUFkmfjJXdBPnrkmeFo88+HVkLfevrGjjvvtQ2Cjw8ergbqAhwfYGf5j8I2BaovrKt9m1kLcVmrp4nq3KQWSmHMWwsvj0Y27wssJMlh/zM=
ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key;
 t=1706313028; c=relaxed/simple;
 bh=X6tB0U6hHGXq57zYpnvCnDtRg1jq/sLW/c8LlVqf4FA=;
 h=Date:From:To:Subject:Message-ID:Mime-Version;
 b=SlapzeXgNfP4sblvQEuSi29cqR0rRUvWjZCIUAoRIs+4LPBuJ1HH/kVX/yonh0dNJQlfU0nfMGtBWdPb3JEUwv/lFIITiTlimKXXnfz6AEspzgOKQtgjP7hzTdsgO3zfGdRY2rTTgIUZzV9AqdxZohtb+5HK+hGLHU3oqTpZv2k=
ARC-Authentication-Results: i=1; server2.sourceware.org
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
 server2.sourceware.org
X-Spam-Language: en
X-Spam-Relay-Country: 
X-Spam-DCC: B=www.nova53.net; R=smtp1.atof.net 1205; Body=1 Fuz1=1 Fuz2=1
X-Spam-RBL: 
X-Spam-PYZOR: Reported 0 times.
Date: Fri, 26 Jan 2024 18:50:19 -0500
To: cygwin AT cygwin DOT com
Cc: Johnothan King <johnothanking AT protonmail DOT com>
Subject: Re: arc4random does not reseed after using fork()
Message-ID: <ZbRFO6gtx0XHMZ5k@xps13>
Mime-Version: 1.0
Content-Disposition: inline
X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00, KAM_DMARC_STATUS,
 SPF_HELO_NONE, SPF_PASS, TXREP,
 T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6
X-BeenThere: cygwin AT cygwin DOT com
X-Mailman-Version: 2.1.30
List-Id: General Cygwin discussions and problem reports <cygwin.cygwin.com>
List-Archive: <https://cygwin.com/pipermail/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-request AT cygwin DOT com?subject=help>
List-Subscribe: <https://cygwin.com/mailman/listinfo/cygwin>,
 <mailto:cygwin-request AT cygwin DOT com?subject=subscribe>
From: Glenn Strauss via Cygwin <cygwin AT cygwin DOT com>
Reply-To: Glenn Strauss <gs-cygwin DOT com AT gluelogic DOT com>
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Sender: "Cygwin" <cygwin-bounces+archive-cygwin=delorie DOT com AT cygwin DOT com>

> While testing ksh93u+m's recently added SRANDOM variable[1], I have
> discovered a bug in Cygwin's arc4random function. After using fork(),
> arc4random does not reseed itself, which causes the results to become
> predictable[2]. Below is a test case C program exhibiting the bug:
> 
> ...
> 
> [1]: https://github.com/ksh93/ksh/commit/00b296c
> [2]: https://github.com/ksh93/ksh/issues/711

FYI: There was a thread in Nov 2023 about rand() which might be related.

rand is not ISO C compliant in Cygwin
https://cygwin.com/pipermail/cygwin/2023-November/254735.html

conclusion of that thread:
https://cygwin.com/pipermail/cygwin/2023-November/254764.html

-- 
Problem reports:      https://cygwin.com/problems.html
FAQ:                  https://cygwin.com/faq/
Documentation:        https://cygwin.com/docs.html
Unsubscribe info:     https://cygwin.com/ml/#unsubscribe-simple