Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932215AbWEATyX (ORCPT ); Mon, 1 May 2006 15:54:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932213AbWEATyE (ORCPT ); Mon, 1 May 2006 15:54:04 -0400 Received: from e4.ny.us.ibm.com ([32.97.182.144]:16525 "EHLO e4.ny.us.ibm.com") by vger.kernel.org with ESMTP id S932215AbWEATx4 (ORCPT ); Mon, 1 May 2006 15:53:56 -0400 From: "Serge E. Hallyn" To: "Serge E. Hallyn" Cc: ebiederm@xmission.com, herbert@13thfloor.at, dev@sw.ru, linux-kernel@vger.kernel.org, sam@vilain.net, xemul@sw.ru, haveblue@us.ibm.com, clg@us.ibm.com, frankeh@us.ibm.com Subject: [PATCH 7/7] uts namespaces: Implement CLONE_NEWUTS flag References: <20060501203906.XF1836@sergelap.austin.ibm.com> Message-ID: <20060501203907.XF1836@sergelap.austin.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Mutt-Fcc: ~/Mail/SENT Date: Mon, 1 May 2006 14:53:52 -0500 (CDT) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5173 Lines: 176 Implement a CLONE_NEWUTS flag, and use it at clone and sys_unshare. Signed-off-by: Serge E. Hallyn --- include/linux/sched.h | 1 + include/linux/utsname.h | 7 ++++++ kernel/fork.c | 13 ++++++++++-- kernel/utsname.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 72 insertions(+), 2 deletions(-) f785920e68ae2482ff76df39d6be5335bbfcc511 diff --git a/include/linux/sched.h b/include/linux/sched.h index 3d74d77..7f4af71 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -62,6 +62,7 @@ #define CLONE_DETACHED 0x00400000 /* Un #define CLONE_UNTRACED 0x00800000 /* set if the tracing process can't force CLONE_PTRACE on this clone */ #define CLONE_CHILD_SETTID 0x01000000 /* set the TID in the child */ #define CLONE_STOPPED 0x02000000 /* Start in stopped state */ +#define CLONE_NEWUTS 0x04000000 /* New utsname group? */ /* * List of flags we want to share for kernel threads, diff --git a/include/linux/utsname.h b/include/linux/utsname.h index d58a406..caecec7 100644 --- a/include/linux/utsname.h +++ b/include/linux/utsname.h @@ -40,6 +40,8 @@ struct uts_namespace { extern struct uts_namespace init_uts_ns; #ifdef CONFIG_UTS_NS +extern int unshare_utsname(unsigned long unshare_flags, + struct uts_namespace **new_uts); extern int copy_utsname(int flags, struct task_struct *tsk); extern void free_uts_ns(struct kref *kref); @@ -70,6 +72,11 @@ static inline void put_uts_ns(struct uts static inline void exit_utsname(struct task_struct *p) { } +static inline int unshare_utsname(unsigned long unshare_flags, + struct uts_namespace **new_uts) +{ + return -EINVAL; +} #endif static inline struct new_utsname *utsname(void) diff --git a/kernel/fork.c b/kernel/fork.c index cedfd86..c52c274 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1566,13 +1566,14 @@ asmlinkage long sys_unshare(unsigned lon struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL; struct files_struct *fd, *new_fd = NULL; struct sem_undo_list *new_ulist = NULL; + struct uts_namespace *new_uts = NULL; check_unshare_flags(&unshare_flags); /* Return -EINVAL for all unsupported flags */ err = -EINVAL; if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| - CLONE_VM|CLONE_FILES|CLONE_SYSVSEM)) + CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|CLONE_NEWUTS)) goto bad_unshare_out; if ((err = unshare_thread(unshare_flags))) @@ -1589,8 +1590,11 @@ asmlinkage long sys_unshare(unsigned lon goto bad_unshare_cleanup_vm; if ((err = unshare_semundo(unshare_flags, &new_ulist))) goto bad_unshare_cleanup_fd; + if ((err = unshare_utsname(unshare_flags, &new_uts))) + goto bad_unshare_cleanup_fd; - if (new_fs || new_ns || new_sigh || new_mm || new_fd || new_ulist) { + if (new_fs || new_ns || new_sigh || new_mm || new_fd || new_ulist || + new_uts) { task_lock(current); @@ -1627,6 +1631,11 @@ asmlinkage long sys_unshare(unsigned lon new_fd = fd; } + if (new_uts) { + put_uts_ns(current->uts_ns); + current->uts_ns = new_uts; + } + task_unlock(current); } diff --git a/kernel/utsname.c b/kernel/utsname.c index f9e8f86..5a97a21 100644 --- a/kernel/utsname.c +++ b/kernel/utsname.c @@ -21,6 +21,41 @@ static inline void get_uts_ns(struct uts } /* + * Clone a new ns copying an original utsname, setting refcount to 1 + * @old_ns: namespace to clone + * Return NULL on error (failure to kmalloc), new ns otherwise + */ +struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns) +{ + struct uts_namespace *ns; + + ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL); + if (ns) { + memcpy(&ns->name, &old_ns->name, sizeof(ns->name)); + kref_init(&ns->kref); + } + return ns; +} + +/* + * unshare the current process' utsname namespace. + * called only in sys_unshare() + */ +int unshare_utsname(unsigned long unshare_flags, struct uts_namespace **new_uts) +{ + if (unshare_flags & CLONE_NEWUTS) { + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + *new_uts = clone_uts_ns(current->uts_ns); + if (!*new_uts) + return -ENOMEM; + } + + return 0; +} + +/* * Copy task tsk's utsname namespace, or clone it if flags * specifies CLONE_NEWUTS. In latter case, changes to the * utsname of this process won't be seen by parent, and vice @@ -29,6 +64,7 @@ static inline void get_uts_ns(struct uts int copy_utsname(int flags, struct task_struct *tsk) { struct uts_namespace *old_ns = tsk->uts_ns; + struct uts_namespace *new_ns; int err = 0; if (!old_ns) @@ -36,6 +72,23 @@ int copy_utsname(int flags, struct task_ get_uts_ns(old_ns); + if (!(flags & CLONE_NEWUTS)) + return 0; + + if (!capable(CAP_SYS_ADMIN)) { + err = -EPERM; + goto out; + } + + new_ns = clone_uts_ns(old_ns); + if (!new_ns) { + err = -ENOMEM; + goto out; + } + tsk->uts_ns = new_ns; + +out: + put_uts_ns(old_ns); return err; } -- 1.3.0 - 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/