From owner-svn-src-all@freebsd.org Thu Jan 30 19:38:12 2020 Return-Path: Delivered-To: svn-src-all@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 EA6DA1FBE4D; Thu, 30 Jan 2020 19:38:12 +0000 (UTC) (envelope-from mjg@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) server-signature RSA-PSS (4096 bits) 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 487rHS5t8Tz4Y27; Thu, 30 Jan 2020 19:38:12 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id C4D681F69; Thu, 30 Jan 2020 19:38:12 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id 00UJcCdY092120; Thu, 30 Jan 2020 19:38:12 GMT (envelope-from mjg@FreeBSD.org) Received: (from mjg@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 00UJcCdQ092119; Thu, 30 Jan 2020 19:38:12 GMT (envelope-from mjg@FreeBSD.org) Message-Id: <202001301938.00UJcCdQ092119@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: mjg set sender to mjg@FreeBSD.org using -f From: Mateusz Guzik Date: Thu, 30 Jan 2020 19:38:12 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r357307 - head/sys/kern X-SVN-Group: head X-SVN-Commit-Author: mjg X-SVN-Commit-Paths: head/sys/kern X-SVN-Commit-Revision: 357307 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 30 Jan 2020 19:38:13 -0000 Author: mjg Date: Thu Jan 30 19:38:12 2020 New Revision: 357307 URL: https://svnweb.freebsd.org/changeset/base/357307 Log: vfs: keep the mount point referenced across sys_quotactl Otherwise we risk running into use-after-free. In particular this codepath ends up dropping all protection before suspending writes: ufs_quotactl -> quotaoff_inchange -> vfs_write_suspend_umnt Reported by: pho Modified: head/sys/kern/vfs_syscalls.c Modified: head/sys/kern/vfs_syscalls.c ============================================================================== --- head/sys/kern/vfs_syscalls.c Thu Jan 30 19:34:37 2020 (r357306) +++ head/sys/kern/vfs_syscalls.c Thu Jan 30 19:38:12 2020 (r357307) @@ -189,9 +189,10 @@ sys_quotactl(struct thread *td, struct quotactl_args * vfs_ref(mp); vput(nd.ni_vp); error = vfs_busy(mp, 0); - vfs_rel(mp); - if (error != 0) + if (error != 0) { + vfs_rel(mp); return (error); + } error = VFS_QUOTACTL(mp, uap->cmd, uap->uid, uap->arg); /* @@ -208,6 +209,7 @@ sys_quotactl(struct thread *td, struct quotactl_args * if ((uap->cmd >> SUBCMDSHIFT) != Q_QUOTAON && (uap->cmd >> SUBCMDSHIFT) != Q_QUOTAOFF) vfs_unbusy(mp); + vfs_rel(mp); return (error); }