Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761362AbYGBGN4 (ORCPT ); Wed, 2 Jul 2008 02:13:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754926AbYGBGNm (ORCPT ); Wed, 2 Jul 2008 02:13:42 -0400 Received: from namei.org ([69.55.235.186]:58970 "EHLO us.intercode.com.au" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754822AbYGBGNl (ORCPT ); Wed, 2 Jul 2008 02:13:41 -0400 Date: Wed, 2 Jul 2008 16:12:44 +1000 (EST) From: James Morris X-X-Sender: jmorris@us.intercode.com.au To: Miklos Szeredi cc: jjohansen@suse.de, Andrew Morton , linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, "Serge E. Hallyn" , "Andrew G. Morgan" Subject: Re: [patch] security: fix dummy xattr functions In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2510 Lines: 71 On Tue, 1 Jul 2008, Miklos Szeredi wrote: > Hi James, > > If this (untested) patch looks OK, could you please apply it to your > tree? As I understand it, filesystem capabilities is only enabled when either LSM is disabled, or the LSM capabilities module is built. In both cases, security/commoncap.o is built. With LSM disabled, the correct cap_inode_xxx functions will be linked. With LSM+capabilities, either the capability LSM will be loaded, or another LSM will need to deliberately stack it. So, I think the existing code is correct. > > Replace open coded xattr checks with cap_inode_xxx() function calls in > dummy_inode_setxattr() and dummy_inode_removexattr(). The old ones > were out of sync with the cap_inode_xxx() implementation, which could > even be a security problem. > > Noticed by John Johansen. > > CC: John Johansen > Signed-off-by: Miklos Szeredi > --- > security/dummy.c | 12 ++---------- > 1 file changed, 2 insertions(+), 10 deletions(-) > > Index: linux-2.6/security/dummy.c > =================================================================== > --- linux-2.6.orig/security/dummy.c 2008-07-01 21:44:03.000000000 +0200 > +++ linux-2.6/security/dummy.c 2008-07-01 21:51:08.000000000 +0200 > @@ -370,11 +370,7 @@ static void dummy_inode_delete (struct i > static int dummy_inode_setxattr (struct dentry *dentry, const char *name, > const void *value, size_t size, int flags) > { > - if (!strncmp(name, XATTR_SECURITY_PREFIX, > - sizeof(XATTR_SECURITY_PREFIX) - 1) && > - !capable(CAP_SYS_ADMIN)) > - return -EPERM; > - return 0; > + return cap_inode_setxattr(dentry, name, value, size, flags); > } > > static void dummy_inode_post_setxattr (struct dentry *dentry, const char *name, > @@ -395,11 +391,7 @@ static int dummy_inode_listxattr (struct > > static int dummy_inode_removexattr (struct dentry *dentry, const char *name) > { > - if (!strncmp(name, XATTR_SECURITY_PREFIX, > - sizeof(XATTR_SECURITY_PREFIX) - 1) && > - !capable(CAP_SYS_ADMIN)) > - return -EPERM; > - return 0; > + return cap_inode_removexattr(dentry, name); > } > > static int dummy_inode_need_killpriv(struct dentry *dentry) > -- James Morris -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/