From owner-svn-src-all@freebsd.org Sun Aug 23 21:05:07 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 4DB623CAF7E; Sun, 23 Aug 2020 21:05:07 +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) 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 4BZSSg1QVTz4WRJ; Sun, 23 Aug 2020 21:05:07 +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 14720DA87; Sun, 23 Aug 2020 21:05:07 +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 07NL56Yh047578; Sun, 23 Aug 2020 21:05:06 GMT (envelope-from mjg@FreeBSD.org) Received: (from mjg@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 07NL56l5047577; Sun, 23 Aug 2020 21:05:06 GMT (envelope-from mjg@FreeBSD.org) Message-Id: <202008232105.07NL56l5047577@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: mjg set sender to mjg@FreeBSD.org using -f From: Mateusz Guzik Date: Sun, 23 Aug 2020 21:05:06 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r364539 - head/sys/kern X-SVN-Group: head X-SVN-Commit-Author: mjg X-SVN-Commit-Paths: head/sys/kern X-SVN-Commit-Revision: 364539 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: 2.1.33 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: Sun, 23 Aug 2020 21:05:07 -0000 Author: mjg Date: Sun Aug 23 21:05:06 2020 New Revision: 364539 URL: https://svnweb.freebsd.org/changeset/base/364539 Log: vfs: support denying access in vaccess_vexec_smr Modified: head/sys/kern/vfs_subr.c Modified: head/sys/kern/vfs_subr.c ============================================================================== --- head/sys/kern/vfs_subr.c Sun Aug 23 21:04:35 2020 (r364538) +++ head/sys/kern/vfs_subr.c Sun Aug 23 21:05:06 2020 (r364539) @@ -5041,8 +5041,6 @@ vn_isdisk(struct vnode *vp) /* * VOP_FPLOOKUP_VEXEC routines are subject to special circumstances, see * the comment above cache_fplookup for details. - * - * We never deny as priv_check_cred calls are not yet supported, see vaccess. */ int vaccess_vexec_smr(mode_t file_mode, uid_t file_uid, gid_t file_gid, struct ucred *cred) @@ -5054,20 +5052,32 @@ vaccess_vexec_smr(mode_t file_mode, uid_t file_uid, gi if (cred->cr_uid == file_uid) { if (file_mode & S_IXUSR) return (0); - return (EAGAIN); + goto out_error; } /* Otherwise, check the groups (first match) */ if (groupmember(file_gid, cred)) { if (file_mode & S_IXGRP) return (0); - return (EAGAIN); + goto out_error; } /* Otherwise, check everyone else. */ if (file_mode & S_IXOTH) return (0); - return (EAGAIN); +out_error: + /* + * Permission check failed. + * + * vaccess() calls priv_check_cred which in turn can descent into MAC + * modules overriding this result. It's quite unclear what semantics + * are allowed for them to operate, thus for safety we don't call them + * from within the SMR section. This also means if any such modules + * are present, we have to let the regular lookup decide. + */ + if (__predict_false(mac_priv_check_fp_flag || mac_priv_grant_fp_flag)) + return (EAGAIN); + return (EACCES); } /*