Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422907AbXBAO5p (ORCPT ); Thu, 1 Feb 2007 09:57:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422909AbXBAO5p (ORCPT ); Thu, 1 Feb 2007 09:57:45 -0500 Received: from mailhub.sw.ru ([195.214.233.200]:2036 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422907AbXBAO5p (ORCPT ); Thu, 1 Feb 2007 09:57:45 -0500 Date: Thu, 1 Feb 2007 18:04:34 +0300 From: Alexey Dobriyan To: akpm@osdl.org Cc: pasky@suse.cz, linux-kernel@vger.kernel.org, devel@openvz.org Subject: [RFC] Allow access to /proc/$PID/fd after setuid() Message-ID: <20070201150434.GA6023@localhost.sw.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1354 Lines: 50 /proc/$PID/fd has r-x------ permissions, so if process does setuid(), it will not be able to access /proc/*/fd/. This breaks fstatat() emulation in glibc. open("foo", O_RDONLY|O_DIRECTORY) = 4 setuid32(65534) = 0 stat64("/proc/self/fd/4/bar", 0xbfafb298) = -1 EACCES (Permission denied) Signed-off-by: Alexey Dobriyan --- fs/proc/base.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1413,11 +1413,27 @@ static struct file_operations proc_fd_op .readdir = proc_readfd, }; +static int proc_fd_permission(struct inode *inode, int mask, struct nameidata *nd) +{ + struct task_struct *tsk; + int rv; + + rv = generic_permission(inode, mask, NULL); + if (rv == 0) + return 0; + tsk = get_proc_task(inode); + if (tsk == current) + rv = 0; + put_task_struct(tsk); + return rv; +} + /* * proc directories can do almost nothing.. */ static struct inode_operations proc_fd_inode_operations = { .lookup = proc_lookupfd, + .permission = proc_fd_permission, .setattr = proc_setattr, }; - 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/