From owner-svn-src-head@freebsd.org Sun Jan 5 03:15:17 2020 Return-Path: Delivered-To: svn-src-head@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 716C81D1FBD; Sun, 5 Jan 2020 03:15:17 +0000 (UTC) (envelope-from kevans@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 47r3fs290Hz3GwS; Sun, 5 Jan 2020 03:15:17 +0000 (UTC) (envelope-from kevans@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 4583B1F374; Sun, 5 Jan 2020 03:15:17 +0000 (UTC) (envelope-from kevans@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id 0053FH3P017273; Sun, 5 Jan 2020 03:15:17 GMT (envelope-from kevans@FreeBSD.org) Received: (from kevans@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 0053FHcb017272; Sun, 5 Jan 2020 03:15:17 GMT (envelope-from kevans@FreeBSD.org) Message-Id: <202001050315.0053FHcb017272@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: kevans set sender to kevans@FreeBSD.org using -f From: Kyle Evans Date: Sun, 5 Jan 2020 03:15:17 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r356371 - head/sys/kern X-SVN-Group: head X-SVN-Commit-Author: kevans X-SVN-Commit-Paths: head/sys/kern X-SVN-Commit-Revision: 356371 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 05 Jan 2020 03:15:17 -0000 Author: kevans Date: Sun Jan 5 03:15:16 2020 New Revision: 356371 URL: https://svnweb.freebsd.org/changeset/base/356371 Log: shmfd/mmap: restrict maxprot with MAP_SHARED + F_SEAL_WRITE If a write seal is set on a shared mapping, we must exclude VM_PROT_WRITE as the fd is effectively read-only. This was discovered by running devel/linux-ltp, which mmap's with acceptable protections specified then attempts to raise to PROT_READ|PROT_WRITE with mprotect(2), which we allowed. Reviewed by: kib Differential Revision: https://reviews.freebsd.org/D22978 Modified: head/sys/kern/uipc_shm.c Modified: head/sys/kern/uipc_shm.c ============================================================================== --- head/sys/kern/uipc_shm.c Sun Jan 5 03:07:59 2020 (r356370) +++ head/sys/kern/uipc_shm.c Sun Jan 5 03:15:16 2020 (r356371) @@ -1116,7 +1116,13 @@ shm_mmap(struct file *fp, vm_map_t map, vm_offset_t *a /* FREAD should always be set. */ if ((fp->f_flag & FREAD) != 0) maxprot |= VM_PROT_EXECUTE | VM_PROT_READ; - if ((fp->f_flag & FWRITE) != 0) + + /* + * If FWRITE's set, we can allow VM_PROT_WRITE unless it's a shared + * mapping with a write seal applied. + */ + if ((fp->f_flag & FWRITE) != 0 && ((flags & MAP_SHARED) == 0 || + (shmfd->shm_seals & F_SEAL_WRITE) == 0)) maxprot |= VM_PROT_WRITE; writecnt = (flags & MAP_SHARED) != 0 && (prot & VM_PROT_WRITE) != 0;