From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934715Ab1KJD0g (ORCPT ); Wed, 9 Nov 2011 22:26:36 -0500 Received: from cantor2.suse.de ([195.135.220.15]:42267 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753774Ab1KJD0c (ORCPT ); Wed, 9 Nov 2011 22:26:32 -0500 X-Mailbox-Line: From gregkh@clark.kroah.org Wed Nov 9 13:27:10 2011 Message-Id: <20111109212709.969022394@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Wed, 09 Nov 2011 13:26:56 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, "J. Bruce Fields" Subject: [094/262] nfsd4: permit read opens of executable-only files In-Reply-To: <20111109212847.GA20838@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: "J. Bruce Fields" commit a043226bc140a2c1dde162246d68a67e5043e6b2 upstream. A client that wants to execute a file must be able to read it. Read opens over nfs are therefore implicitly allowed for executable files even when those files are not readable. NFSv2/v3 get this right by using a passed-in NFSD_MAY_OWNER_OVERRIDE on read requests, but NFSv4 has gotten this wrong ever since dc730e173785e29b297aa605786c94adaffe2544 "nfsd4: fix owner-override on open", when we realized that the file owner shouldn't override permissions on non-reclaim NFSv4 opens. So we can't use NFSD_MAY_OWNER_OVERRIDE to tell nfsd_permission to allow reads of executable files. So, do the same thing we do whenever we encounter another weird NFS permission nit: define yet another NFSD_MAY_* flag. The industry's future standardization on 128-bit processors will be motivated primarily by the need for integers with enough bits for all the NFSD_MAY_* flags. Reported-by: Leonardo Borda Signed-off-by: J. Bruce Fields Signed-off-by: Greg Kroah-Hartman --- fs/nfsd/nfs4proc.c | 2 ++ fs/nfsd/vfs.c | 3 ++- fs/nfsd/vfs.h | 1 + 3 files changed, 5 insertions(+), 1 deletion(-) --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -156,6 +156,8 @@ do_open_permission(struct svc_rqst *rqst !(open->op_share_access & NFS4_SHARE_ACCESS_WRITE)) return nfserr_inval; + accmode |= NFSD_MAY_READ_IF_EXEC; + if (open->op_share_access & NFS4_SHARE_ACCESS_READ) accmode |= NFSD_MAY_READ; if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE) --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -2114,7 +2114,8 @@ nfsd_permission(struct svc_rqst *rqstp, /* Allow read access to binaries even when mode 111 */ if (err == -EACCES && S_ISREG(inode->i_mode) && - acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE)) + (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) || + acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC))) err = inode_permission(inode, MAY_EXEC); return err? nfserrno(err) : 0; --- a/fs/nfsd/vfs.h +++ b/fs/nfsd/vfs.h @@ -25,6 +25,7 @@ #define NFSD_MAY_BYPASS_GSS_ON_ROOT 256 #define NFSD_MAY_NOT_BREAK_LEASE 512 #define NFSD_MAY_BYPASS_GSS 1024 +#define NFSD_MAY_READ_IF_EXEC 2048 #define NFSD_MAY_CREATE (NFSD_MAY_EXEC|NFSD_MAY_WRITE) #define NFSD_MAY_REMOVE (NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC)