X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fnsproxy.c;h=f74e6c00e26d1f50fb1c404b2a6e5505354882bf;hb=0d2daf5cc858bd9305bae187310a1dabaad0a2db;hp=4b7fcc8f9a48f9f329c9a1de80c53c5b17ff87cc;hpb=98c0d07cbf2a8582a0341b05ad564247e608f6f9;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c index 4b7fcc8..f74e6c0 100644 --- a/kernel/nsproxy.c +++ b/kernel/nsproxy.c @@ -13,44 +13,39 @@ * Pavel Emelianov */ +#include #include -#include #include #include #include #include #include +#include +#include static struct kmem_cache *nsproxy_cachep; -struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy); - -static inline void get_nsproxy(struct nsproxy *ns) +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); - } -} - -/* - * creates a copy of "orig" with refcount 1. - */ -static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig) -{ - struct nsproxy *ns; - - ns = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL); - if (ns) { - memcpy(ns, orig, sizeof(struct nsproxy)); - atomic_set(&ns->count, 1); - } - return ns; + nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL); + if (nsproxy) + atomic_set(&nsproxy->count, 1); + return nsproxy; } /* @@ -58,13 +53,13 @@ static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig) * 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 struct nsproxy *create_new_namespaces(int flags, struct task_struct *tsk, - struct fs_struct *new_fs) +static struct nsproxy *create_new_namespaces(unsigned long flags, + struct task_struct *tsk, struct fs_struct *new_fs) { struct nsproxy *new_nsp; int err; - new_nsp = clone_nsproxy(tsk->nsproxy); + new_nsp = create_nsproxy(); if (!new_nsp) return ERR_PTR(-ENOMEM); @@ -86,21 +81,21 @@ static struct nsproxy *create_new_namespaces(int flags, struct task_struct *tsk, goto out_ipc; } - new_nsp->pid_ns = copy_pid_ns(flags, tsk->nsproxy->pid_ns); + 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->user_ns = copy_user_ns(flags, tsk->nsproxy->user_ns); - if (IS_ERR(new_nsp->user_ns)) { - err = PTR_ERR(new_nsp->user_ns); - goto out_user; + 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 new_nsp; -out_user: +out_net: if (new_nsp->pid_ns) put_pid_ns(new_nsp->pid_ns); out_pid: @@ -121,7 +116,7 @@ out_ns: * 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; @@ -132,7 +127,8 @@ int copy_namespaces(int flags, struct task_struct *tsk) get_nsproxy(old_ns); - if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | CLONE_NEWUSER))) + if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | + CLONE_NEWPID | CLONE_NEWNET))) return 0; if (!capable(CAP_SYS_ADMIN)) { @@ -140,6 +136,18 @@ int copy_namespaces(int flags, struct task_struct *tsk) goto out; } + /* + * 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; + } + new_ns = create_new_namespaces(flags, tsk, tsk->fs); if (IS_ERR(new_ns)) { err = PTR_ERR(new_ns); @@ -147,6 +155,7 @@ int copy_namespaces(int flags, struct task_struct *tsk) } tsk->nsproxy = new_ns; + out: put_nsproxy(old_ns); return err; @@ -162,8 +171,7 @@ void free_nsproxy(struct nsproxy *ns) put_ipc_ns(ns->ipc_ns); if (ns->pid_ns) put_pid_ns(ns->pid_ns); - if (ns->user_ns) - put_user_ns(ns->user_ns); + put_net(ns->net_ns); kmem_cache_free(nsproxy_cachep, ns); } @@ -177,7 +185,7 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags, int err = 0; if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | - CLONE_NEWUSER))) + CLONE_NEWNET))) return 0; if (!capable(CAP_SYS_ADMIN)) @@ -185,15 +193,49 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags, *new_nsp = create_new_namespaces(unshare_flags, current, new_fs ? new_fs : current->fs); - if (IS_ERR(*new_nsp)) + 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_create("nsproxy", sizeof(struct nsproxy), - 0, SLAB_PANIC, NULL, NULL); + nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC); return 0; }