From owner-freebsd-bugs@freebsd.org Sun Jul 5 20:30:37 2020 Return-Path: Delivered-To: freebsd-bugs@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 65BD234C4EE for ; Sun, 5 Jul 2020 20:30:37 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.nyi.freebsd.org (mailman.nyi.freebsd.org [IPv6:2610:1c1:1:606c::50:13]) by mx1.freebsd.org (Postfix) with ESMTP id 4B0L1T26V9z4LWG for ; Sun, 5 Jul 2020 20:30:37 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.nyi.freebsd.org (Postfix) id 46A6C34C4ED; Sun, 5 Jul 2020 20:30:37 +0000 (UTC) Delivered-To: bugs@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 455DA34C620 for ; Sun, 5 Jul 2020 20:30:37 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4B0L1T1587z4Lwf for ; Sun, 5 Jul 2020 20:30:37 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2610:1c1:1:606c::50:1d]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 04C2312D38 for ; Sun, 5 Jul 2020 20:30:37 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.5]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id 065KUaWF079187 for ; Sun, 5 Jul 2020 20:30:36 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 065KUaKa079184 for bugs@FreeBSD.org; Sun, 5 Jul 2020 20:30:36 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 247790] PIDs are no longer randomized after reaching pid_max Date: Sun, 05 Jul 2020 20:30:37 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: CURRENT X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: kd-dev@pm.me X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: bugs@FreeBSD.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 attachments.created Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 05 Jul 2020 20:30:37 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D247790 Bug ID: 247790 Summary: PIDs are no longer randomized after reaching pid_max Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: kd-dev@pm.me Created attachment 216234 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=3D216234&action= =3Dedit Wrap `trypid' with a modulus. Overview: If `random' pushes `trypid' over the `max_pid' threshold then `trypid' is reset to 2 and is no-longer randomized. Steps to Reproduce: # sysctl kern.randompid=3D10240 # Unreasonably large for a smaller test # for x in `jot 100`; do > sh -c 'echo $$' > done | awk '{print length}' | sort -n | uniq -c Expected Results: Longer PIDs are orders of magnitude more likely than smaller PIDs. > 1 3 > 8 4 > 91 5 Actual Results: Two-digit PIDs are far more likely than they should be. > 5 2 > 10 4 > 85 5 Additional Information: Only CURRENT is affected. Patch: The attached patch wraps `trypid' with a modulus rather than simply setting it to 2. I have successfully compiled the patch without warnings, and am currently running the patched kernel. --=20 You are receiving this mail because: You are the assignee for the bug.=