Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759441Ab2FEIZT (ORCPT ); Tue, 5 Jun 2012 04:25:19 -0400 Received: from mail-lb0-f174.google.com ([209.85.217.174]:40149 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757943Ab2FEIZQ (ORCPT ); Tue, 5 Jun 2012 04:25:16 -0400 Date: Tue, 5 Jun 2012 12:25:12 +0400 From: Cyrill Gorcunov To: "Eric W. Biederman" Cc: LKML , Andrew Morton , "Serge E. Hallyn" , Oleg Nesterov , Pavel Emelyanov Subject: [PATCH] fcntl: Add F_GETOWNER_UIDS option v3 Message-ID: <20120605082512.GC15171@moon> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3288 Lines: 113 When we restore file descriptors we would like them to look exactly as they were at dumping time. With help of fcntl it's almost possible, the missing snippet is file owners UIDs. To be able to read their values the F_GETOWNER_UIDS is introduced. This option is valid iif CONFIG_CHECKPOINT_RESTORE is turned on, otherwise returning -EINVAL. v3: - rebased on Eric's kuids Signed-off-by: Cyrill Gorcunov CC: "Eric W. Biederman" CC: Andrew Morton CC: "Serge E. Hallyn" CC: Oleg Nesterov CC: Pavel Emelyanov --- fs/fcntl.c | 29 +++++++++++++++++++++++++++++ include/asm-generic/fcntl.h | 4 ++++ security/selinux/hooks.c | 1 + 3 files changed, 34 insertions(+) Index: linux-2.6.git/fs/fcntl.c =================================================================== --- linux-2.6.git.orig/fs/fcntl.c +++ linux-2.6.git/fs/fcntl.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include @@ -340,6 +341,31 @@ static int f_getown_ex(struct file *filp return ret; } +#ifdef CONFIG_CHECKPOINT_RESTORE +static int f_getowner_uids(struct file *filp, unsigned long arg) +{ + struct user_namespace *user_ns = current_user_ns(); + uid_t * __user dst = (void * __user)arg; + uid_t src[2]; + int err; + + read_lock(&filp->f_owner.lock); + src[0] = from_kuid(user_ns, filp->f_owner.uid); + src[1] = from_kuid(user_ns, filp->f_owner.euid); + read_unlock(&filp->f_owner.lock); + + err = put_user(src[0], &dst[0]); + err |= put_user(src[1], &dst[1]); + + return err; +} +#else +static int f_getowner_uids(struct file *filp, unsigned long arg) +{ + return -EINVAL; +} +#endif + static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, struct file *filp) { @@ -396,6 +422,9 @@ static long do_fcntl(int fd, unsigned in case F_SETOWN_EX: err = f_setown_ex(filp, arg); break; + case F_GETOWNER_UIDS: + err = f_getowner_uids(filp, arg); + break; case F_GETSIG: err = filp->f_owner.signum; break; Index: linux-2.6.git/include/asm-generic/fcntl.h =================================================================== --- linux-2.6.git.orig/include/asm-generic/fcntl.h +++ linux-2.6.git/include/asm-generic/fcntl.h @@ -120,6 +120,10 @@ #define F_GETOWN_EX 16 #endif +#ifndef F_GETOWNER_UIDS +#define F_GETOWNER_UIDS 17 +#endif + #define F_OWNER_TID 0 #define F_OWNER_PID 1 #define F_OWNER_PGRP 2 Index: linux-2.6.git/security/selinux/hooks.c =================================================================== --- linux-2.6.git.orig/security/selinux/hooks.c +++ linux-2.6.git/security/selinux/hooks.c @@ -3181,6 +3181,7 @@ static int selinux_file_fcntl(struct fil case F_GETFL: case F_GETOWN: case F_GETSIG: + case F_GETOWNER_UIDS: /* Just check FD__USE permission */ err = file_has_perm(cred, file, 0); break; -- 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/