From owner-freebsd-bugs@freebsd.org Thu Mar 7 23:38:05 2019 Return-Path: Delivered-To: freebsd-bugs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 77870152A3AA for ; Thu, 7 Mar 2019 23:38:05 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.ysv.freebsd.org (mailman.ysv.freebsd.org [IPv6:2001:1900:2254:206a::50:5]) by mx1.freebsd.org (Postfix) with ESMTP id 1027E807BF for ; Thu, 7 Mar 2019 23:38:05 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.ysv.freebsd.org (Postfix) id C4552152A3A9; Thu, 7 Mar 2019 23:38:04 +0000 (UTC) Delivered-To: bugs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id A206C152A3A8 for ; Thu, 7 Mar 2019 23:38:04 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.ysv.freebsd.org (mxrelay.ysv.freebsd.org [IPv6:2001:1900:2254:206a::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.ysv.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 1E8AB807BC for ; Thu, 7 Mar 2019 23:38:04 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.ysv.freebsd.org (Postfix) with ESMTPS id 5E1891A5A2 for ; Thu, 7 Mar 2019 23:38:03 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id x27Nc3gM035837 for ; Thu, 7 Mar 2019 23:38:03 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id x27Nc3qB035836 for bugs@FreeBSD.org; Thu, 7 Mar 2019 23:38:03 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 236379] [FUSE] fuse(4) writes from aio(4) don't set the fuse_out_header.pid field correctly Date: Thu, 07 Mar 2019 23:38:03 +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 Many People X-Bugzilla-Who: asomers@FreeBSD.org 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 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: 2.1.29 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 07 Mar 2019 23:38:05 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D236379 Bug ID: 236379 Summary: [FUSE] fuse(4) writes from aio(4) don't set the fuse_out_header.pid field correctly Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Severity: Affects Many People Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: asomers@FreeBSD.org Every FUSE operation includes the pid of the process that issued the reques= t.=20 However, when an aiod kernel process writes to a fuse-backed file on behalf= of a regular user process, fuse(4) only sees aiod's pid_t, not the user proces= s's. This can cause a fuse filesystem daemon to incorrectly authenticate write commands There are three possible solutions: 1) Set the pid field correctly. The aio daemon already keeps track of it, but doesn't send that information to fuse(4). It's not obvious how. a) Perhaps stuff it into a spare field in struct ucred? b) Define custom fileops for fuse and store the pid that opened a file in struct file.f_data? But this would cause problems when sending a file descriptor from one process to another with sendmsg. 2) Set FUSE_WRITE_CACHE, just like writes from the pager. Currently, howev= er, fuse(4) isn't aware of which operations come from aiod. 3) Alternatively, since FUSE_WRITE is an asynchronous operation, aio(4) could learn to bypass VOP_WRITE and use a threadless direct dispatch like it currently does for disks. That would improve performance, too. This bug probably applies to aio reads as well, but I haven't checked yet. --=20 You are receiving this mail because: You are the assignee for the bug.=