Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 1 | /* |
| 2 | * linux/ipc/namespace.c |
| 3 | * Copyright (C) 2006 Pavel Emelyanov <xemul@openvz.org> OpenVZ, SWsoft Inc. |
| 4 | */ |
| 5 | |
| 6 | #include <linux/ipc.h> |
| 7 | #include <linux/msg.h> |
| 8 | #include <linux/ipc_namespace.h> |
| 9 | #include <linux/rcupdate.h> |
| 10 | #include <linux/nsproxy.h> |
| 11 | #include <linux/slab.h> |
Serge E. Hallyn | 7eafd7c | 2009-04-06 19:01:10 -0700 | [diff] [blame] | 12 | #include <linux/fs.h> |
| 13 | #include <linux/mount.h> |
Serge E. Hallyn | b515498 | 2011-03-23 16:43:23 -0700 | [diff] [blame] | 14 | #include <linux/user_namespace.h> |
David Howells | 0bb80f2 | 2013-04-12 01:50:06 +0100 | [diff] [blame] | 15 | #include <linux/proc_ns.h> |
Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 16 | |
| 17 | #include "util.h" |
| 18 | |
Eric W. Biederman | bcf58e7 | 2012-07-26 04:02:49 -0700 | [diff] [blame] | 19 | static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns, |
Serge E. Hallyn | b0e7759 | 2011-03-23 16:43:24 -0700 | [diff] [blame] | 20 | struct ipc_namespace *old_ns) |
Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 21 | { |
Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 22 | struct ipc_namespace *ns; |
Serge E. Hallyn | 7eafd7c | 2009-04-06 19:01:10 -0700 | [diff] [blame] | 23 | int err; |
Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 24 | |
Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 25 | ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL); |
| 26 | if (ns == NULL) |
Pierre Peiffer | ed2ddbf | 2008-02-08 04:18:57 -0800 | [diff] [blame] | 27 | return ERR_PTR(-ENOMEM); |
Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 28 | |
Al Viro | 6344c43 | 2014-11-01 00:45:45 -0400 | [diff] [blame] | 29 | err = ns_alloc_inum(&ns->ns); |
Eric W. Biederman | 98f842e | 2011-06-15 10:21:48 -0700 | [diff] [blame] | 30 | if (err) { |
| 31 | kfree(ns); |
| 32 | return ERR_PTR(err); |
| 33 | } |
Al Viro | 33c4294 | 2014-11-01 02:32:53 -0400 | [diff] [blame^] | 34 | ns->ns.ops = &ipcns_operations; |
Eric W. Biederman | 98f842e | 2011-06-15 10:21:48 -0700 | [diff] [blame] | 35 | |
Serge E. Hallyn | 7eafd7c | 2009-04-06 19:01:10 -0700 | [diff] [blame] | 36 | atomic_set(&ns->count, 1); |
| 37 | err = mq_init_ns(ns); |
| 38 | if (err) { |
Al Viro | 6344c43 | 2014-11-01 00:45:45 -0400 | [diff] [blame] | 39 | ns_free_inum(&ns->ns); |
Serge E. Hallyn | 7eafd7c | 2009-04-06 19:01:10 -0700 | [diff] [blame] | 40 | kfree(ns); |
| 41 | return ERR_PTR(err); |
| 42 | } |
Nadia Derbey | 4d89dc6 | 2008-04-29 01:00:40 -0700 | [diff] [blame] | 43 | atomic_inc(&nr_ipc_ns); |
| 44 | |
Pierre Peiffer | ed2ddbf | 2008-02-08 04:18:57 -0800 | [diff] [blame] | 45 | sem_init_ns(ns); |
| 46 | msg_init_ns(ns); |
| 47 | shm_init_ns(ns); |
Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 48 | |
Nadia Derbey | e2c284d | 2008-04-29 01:00:44 -0700 | [diff] [blame] | 49 | /* |
| 50 | * msgmni has already been computed for the new ipc ns. |
| 51 | * Thus, do the ipcns creation notification before registering that |
| 52 | * new ipcns in the chain. |
| 53 | */ |
| 54 | ipcns_notify(IPCNS_CREATED); |
Nadia Derbey | b6b337a | 2008-04-29 01:00:42 -0700 | [diff] [blame] | 55 | register_ipcns_notifier(ns); |
| 56 | |
Eric W. Biederman | bcf58e7 | 2012-07-26 04:02:49 -0700 | [diff] [blame] | 57 | ns->user_ns = get_user_ns(user_ns); |
Serge E. Hallyn | b515498 | 2011-03-23 16:43:23 -0700 | [diff] [blame] | 58 | |
Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 59 | return ns; |
Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 60 | } |
| 61 | |
Serge E. Hallyn | b0e7759 | 2011-03-23 16:43:24 -0700 | [diff] [blame] | 62 | struct ipc_namespace *copy_ipcs(unsigned long flags, |
Eric W. Biederman | bcf58e7 | 2012-07-26 04:02:49 -0700 | [diff] [blame] | 63 | struct user_namespace *user_ns, struct ipc_namespace *ns) |
Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 64 | { |
Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 65 | if (!(flags & CLONE_NEWIPC)) |
Alexey Dobriyan | 6442428 | 2009-06-17 16:27:54 -0700 | [diff] [blame] | 66 | return get_ipc_ns(ns); |
Eric W. Biederman | bcf58e7 | 2012-07-26 04:02:49 -0700 | [diff] [blame] | 67 | return create_ipc_ns(user_ns, ns); |
Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 68 | } |
| 69 | |
Pierre Peiffer | 01b8b07 | 2008-02-08 04:18:57 -0800 | [diff] [blame] | 70 | /* |
| 71 | * free_ipcs - free all ipcs of one type |
| 72 | * @ns: the namespace to remove the ipcs from |
| 73 | * @ids: the table of ipcs to free |
| 74 | * @free: the function called to free each individual ipc |
| 75 | * |
| 76 | * Called for each kind of ipc when an ipc_namespace exits. |
| 77 | */ |
| 78 | void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, |
| 79 | void (*free)(struct ipc_namespace *, struct kern_ipc_perm *)) |
| 80 | { |
| 81 | struct kern_ipc_perm *perm; |
| 82 | int next_id; |
| 83 | int total, in_use; |
| 84 | |
Davidlohr Bueso | d9a605e | 2013-09-11 14:26:24 -0700 | [diff] [blame] | 85 | down_write(&ids->rwsem); |
Pierre Peiffer | 01b8b07 | 2008-02-08 04:18:57 -0800 | [diff] [blame] | 86 | |
| 87 | in_use = ids->in_use; |
| 88 | |
| 89 | for (total = 0, next_id = 0; total < in_use; next_id++) { |
| 90 | perm = idr_find(&ids->ipcs_idr, next_id); |
| 91 | if (perm == NULL) |
| 92 | continue; |
Davidlohr Bueso | 32a2750 | 2013-09-11 14:26:29 -0700 | [diff] [blame] | 93 | rcu_read_lock(); |
| 94 | ipc_lock_object(perm); |
Pierre Peiffer | 01b8b07 | 2008-02-08 04:18:57 -0800 | [diff] [blame] | 95 | free(ns, perm); |
| 96 | total++; |
| 97 | } |
Davidlohr Bueso | d9a605e | 2013-09-11 14:26:24 -0700 | [diff] [blame] | 98 | up_write(&ids->rwsem); |
Pierre Peiffer | 01b8b07 | 2008-02-08 04:18:57 -0800 | [diff] [blame] | 99 | } |
| 100 | |
Alexey Dobriyan | b4188de | 2009-06-17 16:27:56 -0700 | [diff] [blame] | 101 | static void free_ipc_ns(struct ipc_namespace *ns) |
| 102 | { |
| 103 | /* |
| 104 | * Unregistering the hotplug notifier at the beginning guarantees |
| 105 | * that the ipc namespace won't be freed while we are inside the |
| 106 | * callback routine. Since the blocking_notifier_chain_XXX routines |
| 107 | * hold a rw lock on the notifier list, unregister_ipcns_notifier() |
| 108 | * won't take the rw lock before blocking_notifier_call_chain() has |
| 109 | * released the rd lock. |
| 110 | */ |
| 111 | unregister_ipcns_notifier(ns); |
| 112 | sem_exit_ns(ns); |
| 113 | msg_exit_ns(ns); |
| 114 | shm_exit_ns(ns); |
Alexey Dobriyan | b4188de | 2009-06-17 16:27:56 -0700 | [diff] [blame] | 115 | atomic_dec(&nr_ipc_ns); |
| 116 | |
| 117 | /* |
| 118 | * Do the ipcns removal notification after decrementing nr_ipc_ns in |
| 119 | * order to have a correct value when recomputing msgmni. |
| 120 | */ |
| 121 | ipcns_notify(IPCNS_REMOVED); |
Serge E. Hallyn | b515498 | 2011-03-23 16:43:23 -0700 | [diff] [blame] | 122 | put_user_ns(ns->user_ns); |
Al Viro | 6344c43 | 2014-11-01 00:45:45 -0400 | [diff] [blame] | 123 | ns_free_inum(&ns->ns); |
Xiaotian Feng | be4d250 | 2011-03-25 01:57:01 -0700 | [diff] [blame] | 124 | kfree(ns); |
Alexey Dobriyan | b4188de | 2009-06-17 16:27:56 -0700 | [diff] [blame] | 125 | } |
| 126 | |
Serge E. Hallyn | 7eafd7c | 2009-04-06 19:01:10 -0700 | [diff] [blame] | 127 | /* |
| 128 | * put_ipc_ns - drop a reference to an ipc namespace. |
| 129 | * @ns: the namespace to put |
| 130 | * |
| 131 | * If this is the last task in the namespace exiting, and |
| 132 | * it is dropping the refcount to 0, then it can race with |
| 133 | * a task in another ipc namespace but in a mounts namespace |
| 134 | * which has this ipcns's mqueuefs mounted, doing some action |
| 135 | * with one of the mqueuefs files. That can raise the refcount. |
| 136 | * So dropping the refcount, and raising the refcount when |
| 137 | * accessing it through the VFS, are protected with mq_lock. |
| 138 | * |
| 139 | * (Clearly, a task raising the refcount on its own ipc_ns |
| 140 | * needn't take mq_lock since it can't race with the last task |
| 141 | * in the ipcns exiting). |
| 142 | */ |
| 143 | void put_ipc_ns(struct ipc_namespace *ns) |
Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 144 | { |
Serge E. Hallyn | 7eafd7c | 2009-04-06 19:01:10 -0700 | [diff] [blame] | 145 | if (atomic_dec_and_lock(&ns->count, &mq_lock)) { |
| 146 | mq_clear_sbinfo(ns); |
| 147 | spin_unlock(&mq_lock); |
| 148 | mq_put_mnt(ns); |
| 149 | free_ipc_ns(ns); |
| 150 | } |
| 151 | } |
Eric W. Biederman | a00eaf1 | 2010-03-07 18:48:39 -0800 | [diff] [blame] | 152 | |
Al Viro | 3c04118 | 2014-11-01 00:25:30 -0400 | [diff] [blame] | 153 | static inline struct ipc_namespace *to_ipc_ns(struct ns_common *ns) |
| 154 | { |
| 155 | return container_of(ns, struct ipc_namespace, ns); |
| 156 | } |
| 157 | |
Al Viro | 6496452 | 2014-11-01 00:37:32 -0400 | [diff] [blame] | 158 | static struct ns_common *ipcns_get(struct task_struct *task) |
Eric W. Biederman | a00eaf1 | 2010-03-07 18:48:39 -0800 | [diff] [blame] | 159 | { |
| 160 | struct ipc_namespace *ns = NULL; |
| 161 | struct nsproxy *nsproxy; |
| 162 | |
Eric W. Biederman | 728dba3 | 2014-02-03 19:13:49 -0800 | [diff] [blame] | 163 | task_lock(task); |
| 164 | nsproxy = task->nsproxy; |
Eric W. Biederman | a00eaf1 | 2010-03-07 18:48:39 -0800 | [diff] [blame] | 165 | if (nsproxy) |
| 166 | ns = get_ipc_ns(nsproxy->ipc_ns); |
Eric W. Biederman | 728dba3 | 2014-02-03 19:13:49 -0800 | [diff] [blame] | 167 | task_unlock(task); |
Eric W. Biederman | a00eaf1 | 2010-03-07 18:48:39 -0800 | [diff] [blame] | 168 | |
Al Viro | 3c04118 | 2014-11-01 00:25:30 -0400 | [diff] [blame] | 169 | return ns ? &ns->ns : NULL; |
Eric W. Biederman | a00eaf1 | 2010-03-07 18:48:39 -0800 | [diff] [blame] | 170 | } |
| 171 | |
Al Viro | 6496452 | 2014-11-01 00:37:32 -0400 | [diff] [blame] | 172 | static void ipcns_put(struct ns_common *ns) |
Eric W. Biederman | a00eaf1 | 2010-03-07 18:48:39 -0800 | [diff] [blame] | 173 | { |
Al Viro | 3c04118 | 2014-11-01 00:25:30 -0400 | [diff] [blame] | 174 | return put_ipc_ns(to_ipc_ns(ns)); |
Eric W. Biederman | a00eaf1 | 2010-03-07 18:48:39 -0800 | [diff] [blame] | 175 | } |
| 176 | |
Al Viro | 6496452 | 2014-11-01 00:37:32 -0400 | [diff] [blame] | 177 | static int ipcns_install(struct nsproxy *nsproxy, struct ns_common *new) |
Eric W. Biederman | a00eaf1 | 2010-03-07 18:48:39 -0800 | [diff] [blame] | 178 | { |
Al Viro | 3c04118 | 2014-11-01 00:25:30 -0400 | [diff] [blame] | 179 | struct ipc_namespace *ns = to_ipc_ns(new); |
Eric W. Biederman | 5e4a084 | 2012-12-14 07:55:36 -0800 | [diff] [blame] | 180 | if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) || |
Eric W. Biederman | c7b96ac | 2013-03-20 12:49:49 -0700 | [diff] [blame] | 181 | !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) |
Eric W. Biederman | 142e1d1 | 2012-07-26 01:13:20 -0700 | [diff] [blame] | 182 | return -EPERM; |
| 183 | |
Eric W. Biederman | a00eaf1 | 2010-03-07 18:48:39 -0800 | [diff] [blame] | 184 | /* Ditch state from the old ipc namespace */ |
| 185 | exit_sem(current); |
| 186 | put_ipc_ns(nsproxy->ipc_ns); |
| 187 | nsproxy->ipc_ns = get_ipc_ns(ns); |
| 188 | return 0; |
| 189 | } |
| 190 | |
| 191 | const struct proc_ns_operations ipcns_operations = { |
| 192 | .name = "ipc", |
| 193 | .type = CLONE_NEWIPC, |
| 194 | .get = ipcns_get, |
| 195 | .put = ipcns_put, |
| 196 | .install = ipcns_install, |
| 197 | }; |