From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5ADCCC433F5 for ; Sat, 30 Oct 2021 16:42:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3965F60E73 for ; Sat, 30 Oct 2021 16:42:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229734AbhJ3Qod (ORCPT ); Sat, 30 Oct 2021 12:44:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:38250 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229694AbhJ3Qod (ORCPT ); Sat, 30 Oct 2021 12:44:33 -0400 Received: by mail.kernel.org (Postfix) with ESMTPS id E394360E76 for ; Sat, 30 Oct 2021 16:42:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1635612122; bh=KMfJe1FBKQjNN2F6fBUXowMe0UREbfngf0LrIXQ3Afc=; h=From:To:Subject:Date:From; b=RJPN3dJn1Vs5chB3gvwSBR3h/TSAsSWH3NDi4frPz1Ag5IapZERV+AFM/cLUB88OL nohL3A4Vt0buEP9T/8BTvqpDtbOMyTS7Ft+kJ8BpjS1fchS5ccmb0ewwnKmz/MFGVx rhMDU6lPCTI2IEPwgESoe19NMCrEXQNA3B70YEo38L4k/j2opek2v8eiXQVWMrvJ8L HqWG2vXK5z7zj5K500KCVcCtFS5vhxW7QpLBI9+oDoWlzf4QkNDFVMeUZzfy3wrUcU aObBt8rflPFTMZj0bEPKV5aR/0IlWTEx6HSyQ/I9eEqO4aH867v1Q8YvEhfHt4Nlak uzo+94TMqNUMg== From: bugzilla-daemon@bugzilla.kernel.org To: linux-man@vger.kernel.org Subject: [Bug 214885] New: random.{4,7} [man-pages 5.13] do not reflect changes to /dev/random semantics since kernel 5.6 Date: Sat, 30 Oct 2021 16:42:02 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: AssignedTo documentation_man-pages@kernel-bugs.osdl.org X-Bugzilla-Product: Documentation X-Bugzilla-Component: man-pages X-Bugzilla-Version: unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: low X-Bugzilla-Who: kerbug@zplane.com X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P1 X-Bugzilla-Assigned-To: documentation_man-pages@kernel-bugs.osdl.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter cf_regression Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-man@vger.kernel.org https://bugzilla.kernel.org/show_bug.cgi?id=3D214885 Bug ID: 214885 Summary: random.{4,7} [man-pages 5.13] do not reflect changes to /dev/random semantics since kernel 5.6 Product: Documentation Version: unspecified Hardware: All OS: Linux Status: NEW Severity: low Priority: P1 Component: man-pages Assignee: documentation_man-pages@kernel-bugs.osdl.org Reporter: kerbug@zplane.com Regression: No In kernel 5.6, the semantics of reading from /dev/random were changed significantly [1][2]. If my understanding of [1] is correct -- and perhaps = it is not, I am not claiming any expertise -- /dev/random now behaves essentia= lly like /dev/urandom, except that it blocks only in the case of insufficient initial entropy during boot, but never blocks thereafter. A few quick experiments using kernel 5.14.14 seem to confirm that understanding. This is a significant behavioral change but it does not seem to be reflecte= d in either random.4 or random.7 from man-pages release 5.13 (as provided in Arch Linux man-pages 5.13-1). In looking thru the change history of those pages,= it does not seem that there have been any updates to either since man-pages 4.= 10.=20 I'd be happy to offer a patch, but the required changes are not trivial and= am hestitant to contribute language on something that I don't have sufficient familiarity with.=20 Based on my quick experiments with kernel 5.14.14, at least the following statements in random.4 seem to be entirely invalidated by the post 5.6 behavior: A read(2) from /dev/random will return at most 512 bytes (340 bytes on Linux kernels before version 2.6.12): Observed behavior with 5.14.14: It returns up to 32MB, just as /dev/urandom does. The subsection describing read_wakeup_threshold: This pseudo-file read_wakeup_threshold no longer exists in /proc/sys/kernel/random. - Glenn [1] https://github.com/torvalds/linux/commit/30c08efec8884fb106b8e57094baa51bb4= c44e32 [2] https://lwn.net/Articles/808575/ --=20 You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.=