From e3222c4ecc649c4ae568e61dda9349482401b501 Mon Sep 17 00:00:00 2001 From: Badari Pulavarty Date: Tue, 8 May 2007 00:25:21 -0700 Subject: Merge sys_clone()/sys_unshare() nsproxy and namespace handling sys_clone() and sys_unshare() both makes copies of nsproxy and its associated namespaces. But they have different code paths. This patch merges all the nsproxy and its associated namespace copy/clone handling (as much as possible). Posted on container list earlier for feedback. - Create a new nsproxy and its associated namespaces and pass it back to caller to attach it to right process. - Changed all copy_*_ns() routines to return a new copy of namespace instead of attaching it to task->nsproxy. - Moved the CAP_SYS_ADMIN checks out of copy_*_ns() routines. - Removed unnessary !ns checks from copy_*_ns() and added BUG_ON() just incase. - Get rid of all individual unshare_*_ns() routines and make use of copy_*_ns() instead. [akpm@osdl.org: cleanups, warning fix] [clg@fr.ibm.com: remove dup_namespaces() declaration] [serue@us.ibm.com: fix CONFIG_IPC_NS=n, clone(CLONE_NEWIPC) retval] [akpm@linux-foundation.org: fix build with CONFIG_SYSVIPC=n] Signed-off-by: Badari Pulavarty Signed-off-by: Serge Hallyn Cc: Cedric Le Goater Cc: "Eric W. Biederman" Cc: Signed-off-by: Cedric Le Goater Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/nsproxy.c | 139 ++++++++++++++++++++++++++++++++++--------------------- 1 file changed, 86 insertions(+), 53 deletions(-) (limited to 'kernel/nsproxy.c') diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c index f5b9ee6f6bb..1bc4b55241a 100644 --- a/kernel/nsproxy.c +++ b/kernel/nsproxy.c @@ -38,10 +38,8 @@ void get_task_namespaces(struct task_struct *tsk) /* * creates a copy of "orig" with refcount 1. - * This does not grab references to the contained namespaces, - * so that needs to be done by dup_namespaces. */ -static inline struct nsproxy *clone_namespaces(struct nsproxy *orig) +static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig) { struct nsproxy *ns; @@ -52,26 +50,49 @@ static inline struct nsproxy *clone_namespaces(struct nsproxy *orig) } /* - * copies the nsproxy, setting refcount to 1, and grabbing a - * reference to all contained namespaces. Called from - * sys_unshare() + * Create new nsproxy and all of its the associated namespaces. + * Return the newly created nsproxy. Do not attach this to the task, + * leave it to the caller to do proper locking and attach it to task. */ -struct nsproxy *dup_namespaces(struct nsproxy *orig) +static struct nsproxy *create_new_namespaces(int flags, struct task_struct *tsk, + struct fs_struct *new_fs) { - struct nsproxy *ns = clone_namespaces(orig); + struct nsproxy *new_nsp; - if (ns) { - if (ns->mnt_ns) - get_mnt_ns(ns->mnt_ns); - if (ns->uts_ns) - get_uts_ns(ns->uts_ns); - if (ns->ipc_ns) - get_ipc_ns(ns->ipc_ns); - if (ns->pid_ns) - get_pid_ns(ns->pid_ns); - } + new_nsp = clone_nsproxy(tsk->nsproxy); + if (!new_nsp) + return ERR_PTR(-ENOMEM); - return ns; + new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs); + if (IS_ERR(new_nsp->mnt_ns)) + goto out_ns; + + new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns); + if (IS_ERR(new_nsp->uts_ns)) + goto out_uts; + + new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns); + if (IS_ERR(new_nsp->ipc_ns)) + goto out_ipc; + + new_nsp->pid_ns = copy_pid_ns(flags, tsk->nsproxy->pid_ns); + if (IS_ERR(new_nsp->pid_ns)) + goto out_pid; + + return new_nsp; + +out_pid: + if (new_nsp->ipc_ns) + put_ipc_ns(new_nsp->ipc_ns); +out_ipc: + if (new_nsp->uts_ns) + put_uts_ns(new_nsp->uts_ns); +out_uts: + if (new_nsp->mnt_ns) + put_mnt_ns(new_nsp->mnt_ns); +out_ns: + kfree(new_nsp); + return ERR_PTR(-ENOMEM); } /* @@ -92,47 +113,21 @@ int copy_namespaces(int flags, struct task_struct *tsk) if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC))) return 0; - new_ns = clone_namespaces(old_ns); - if (!new_ns) { - err = -ENOMEM; + if (!capable(CAP_SYS_ADMIN)) { + err = -EPERM; goto out; } - tsk->nsproxy = new_ns; - - err = copy_mnt_ns(flags, tsk); - if (err) - goto out_ns; - - err = copy_utsname(flags, tsk); - if (err) - goto out_uts; - - err = copy_ipcs(flags, tsk); - if (err) - goto out_ipc; - - err = copy_pid_ns(flags, tsk); - if (err) - goto out_pid; + new_ns = create_new_namespaces(flags, tsk, tsk->fs); + if (IS_ERR(new_ns)) { + err = PTR_ERR(new_ns); + goto out; + } + tsk->nsproxy = new_ns; out: put_nsproxy(old_ns); return err; - -out_pid: - if (new_ns->ipc_ns) - put_ipc_ns(new_ns->ipc_ns); -out_ipc: - if (new_ns->uts_ns) - put_uts_ns(new_ns->uts_ns); -out_uts: - if (new_ns->mnt_ns) - put_mnt_ns(new_ns->mnt_ns); -out_ns: - tsk->nsproxy = old_ns; - kfree(new_ns); - goto out; } void free_nsproxy(struct nsproxy *ns) @@ -147,3 +142,41 @@ void free_nsproxy(struct nsproxy *ns) put_pid_ns(ns->pid_ns); kfree(ns); } + +/* + * Called from unshare. Unshare all the namespaces part of nsproxy. + * On sucess, returns the new nsproxy and a reference to old nsproxy + * to make sure it stays around. + */ +int unshare_nsproxy_namespaces(unsigned long unshare_flags, + struct nsproxy **new_nsp, struct fs_struct *new_fs) +{ + struct nsproxy *old_ns = current->nsproxy; + int err = 0; + + if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC))) + return 0; + +#ifndef CONFIG_IPC_NS + if (unshare_flags & CLONE_NEWIPC) + return -EINVAL; +#endif + +#ifndef CONFIG_UTS_NS + if (unshare_flags & CLONE_NEWUTS) + return -EINVAL; +#endif + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + get_nsproxy(old_ns); + + *new_nsp = create_new_namespaces(unshare_flags, current, + new_fs ? new_fs : current->fs); + if (IS_ERR(*new_nsp)) { + err = PTR_ERR(*new_nsp); + put_nsproxy(old_ns); + } + return err; +} -- cgit v1.2.3