X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fnsproxy.c;h=f74e6c00e26d1f50fb1c404b2a6e5505354882bf;hb=8fade6aff706b2ae3f02864b4023d34b002cd226;hp=e2ce748e96afaca08cf0e5b2821d4cf6e8cab823;hpb=9a575a92db3312a40cdf0b0406d88de88ad9741e;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c index e2ce748..f74e6c0 100644 --- a/kernel/nsproxy.c +++ b/kernel/nsproxy.c @@ -13,74 +13,110 @@ * Pavel Emelianov */ +#include #include -#include #include #include #include #include #include - -struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy); - -static inline void get_nsproxy(struct nsproxy *ns) +#include +#include + +static struct kmem_cache *nsproxy_cachep; + +struct nsproxy init_nsproxy = { + .count = ATOMIC_INIT(1), + .uts_ns = &init_uts_ns, +#if defined(CONFIG_POSIX_MQUEUE) || defined(CONFIG_SYSVIPC) + .ipc_ns = &init_ipc_ns, +#endif + .mnt_ns = NULL, + .pid_ns = &init_pid_ns, +#ifdef CONFIG_NET + .net_ns = &init_net, +#endif +}; + +static inline struct nsproxy *create_nsproxy(void) { - atomic_inc(&ns->count); -} + struct nsproxy *nsproxy; -void get_task_namespaces(struct task_struct *tsk) -{ - struct nsproxy *ns = tsk->nsproxy; - if (ns) { - get_nsproxy(ns); - } + nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL); + if (nsproxy) + atomic_set(&nsproxy->count, 1); + return nsproxy; } /* - * 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. + * 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. */ -static inline struct nsproxy *clone_namespaces(struct nsproxy *orig) +static struct nsproxy *create_new_namespaces(unsigned long flags, + struct task_struct *tsk, struct fs_struct *new_fs) { - struct nsproxy *ns; + struct nsproxy *new_nsp; + int err; + + new_nsp = create_nsproxy(); + if (!new_nsp) + return ERR_PTR(-ENOMEM); - ns = kmemdup(orig, sizeof(struct nsproxy), GFP_KERNEL); - if (ns) { - atomic_set(&ns->count, 1); - ns->id = -1; + new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs); + if (IS_ERR(new_nsp->mnt_ns)) { + err = PTR_ERR(new_nsp->mnt_ns); + goto out_ns; } - return ns; -} -/* - * copies the nsproxy, setting refcount to 1, and grabbing a - * reference to all contained namespaces. Called from - * sys_unshare() - */ -struct nsproxy *dup_namespaces(struct nsproxy *orig) -{ - struct nsproxy *ns = clone_namespaces(orig); - - 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->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns); + if (IS_ERR(new_nsp->uts_ns)) { + err = PTR_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)) { + err = PTR_ERR(new_nsp->ipc_ns); + goto out_ipc; + } + + new_nsp->pid_ns = copy_pid_ns(flags, task_active_pid_ns(tsk)); + if (IS_ERR(new_nsp->pid_ns)) { + err = PTR_ERR(new_nsp->pid_ns); + goto out_pid; + } + + new_nsp->net_ns = copy_net_ns(flags, tsk->nsproxy->net_ns); + if (IS_ERR(new_nsp->net_ns)) { + err = PTR_ERR(new_nsp->net_ns); + goto out_net; } - return ns; + return new_nsp; + +out_net: + if (new_nsp->pid_ns) + put_pid_ns(new_nsp->pid_ns); +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: + kmem_cache_free(nsproxy_cachep, new_nsp); + return ERR_PTR(err); } /* * called from clone. This now handles copy for nsproxy and all * namespaces therein. */ -int copy_namespaces(int flags, struct task_struct *tsk) +int copy_namespaces(unsigned long flags, struct task_struct *tsk) { struct nsproxy *old_ns = tsk->nsproxy; struct nsproxy *new_ns; @@ -91,50 +127,38 @@ int copy_namespaces(int flags, struct task_struct *tsk) get_nsproxy(old_ns); - if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC))) + if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | + CLONE_NEWPID | CLONE_NEWNET))) 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; + /* + * CLONE_NEWIPC must detach from the undolist: after switching + * to a new ipc namespace, the semaphore arrays from the old + * namespace are unreachable. In clone parlance, CLONE_SYSVSEM + * means share undolist with parent, so we must forbid using + * it along with CLONE_NEWIPC. + */ + if ((flags & CLONE_NEWIPC) && (flags & CLONE_SYSVSEM)) { + err = -EINVAL; + goto out; + } - err = copy_ipcs(flags, tsk); - if (err) - goto out_ipc; + new_ns = create_new_namespaces(flags, tsk, tsk->fs); + if (IS_ERR(new_ns)) { + err = PTR_ERR(new_ns); + goto out; + } - err = copy_pid_ns(flags, tsk); - if (err) - goto out_pid; + 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) @@ -147,5 +171,72 @@ void free_nsproxy(struct nsproxy *ns) put_ipc_ns(ns->ipc_ns); if (ns->pid_ns) put_pid_ns(ns->pid_ns); - kfree(ns); + put_net(ns->net_ns); + kmem_cache_free(nsproxy_cachep, ns); +} + +/* + * Called from unshare. Unshare all the namespaces part of nsproxy. + * On success, returns the new nsproxy. + */ +int unshare_nsproxy_namespaces(unsigned long unshare_flags, + struct nsproxy **new_nsp, struct fs_struct *new_fs) +{ + int err = 0; + + if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | + CLONE_NEWNET))) + return 0; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + *new_nsp = create_new_namespaces(unshare_flags, current, + new_fs ? new_fs : current->fs); + if (IS_ERR(*new_nsp)) { + err = PTR_ERR(*new_nsp); + goto out; + } + + err = ns_cgroup_clone(current, task_pid(current)); + if (err) + put_nsproxy(*new_nsp); + +out: + return err; +} + +void switch_task_namespaces(struct task_struct *p, struct nsproxy *new) +{ + struct nsproxy *ns; + + might_sleep(); + + ns = p->nsproxy; + + rcu_assign_pointer(p->nsproxy, new); + + if (ns && atomic_dec_and_test(&ns->count)) { + /* + * wait for others to get what they want from this nsproxy. + * + * cannot release this nsproxy via the call_rcu() since + * put_mnt_ns() will want to sleep + */ + synchronize_rcu(); + free_nsproxy(ns); + } +} + +void exit_task_namespaces(struct task_struct *p) +{ + switch_task_namespaces(p, NULL); } + +static int __init nsproxy_cache_init(void) +{ + nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC); + return 0; +} + +module_init(nsproxy_cache_init);