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>
 
 12#include <linux/fs.h>
 13#include <linux/mount.h>
 14#include <linux/user_namespace.h>
 15#include <linux/proc_ns.h>
 
 16
 17#include "util.h"
 18
 19static struct ucounts *inc_ipc_namespaces(struct user_namespace *ns)
 20{
 21	return inc_ucount(ns, current_euid(), UCOUNT_IPC_NAMESPACES);
 22}
 23
 24static void dec_ipc_namespaces(struct ucounts *ucounts)
 25{
 26	dec_ucount(ucounts, UCOUNT_IPC_NAMESPACES);
 27}
 28
 29static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
 30					   struct ipc_namespace *old_ns)
 31{
 32	struct ipc_namespace *ns;
 33	struct ucounts *ucounts;
 34	int err;
 35
 36	err = -ENOSPC;
 37	ucounts = inc_ipc_namespaces(user_ns);
 38	if (!ucounts)
 39		goto fail;
 40
 41	err = -ENOMEM;
 42	ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
 43	if (ns == NULL)
 44		goto fail_dec;
 45
 46	err = ns_alloc_inum(&ns->ns);
 47	if (err)
 48		goto fail_free;
 49	ns->ns.ops = &ipcns_operations;
 50
 51	atomic_set(&ns->count, 1);
 52	ns->user_ns = get_user_ns(user_ns);
 53	ns->ucounts = ucounts;
 54
 55	err = mq_init_ns(ns);
 56	if (err)
 57		goto fail_put;
 58
 
 
 
 
 
 
 
 
 
 
 
 59	sem_init_ns(ns);
 60	msg_init_ns(ns);
 61	shm_init_ns(ns);
 62
 63	return ns;
 64
 
 
 
 65fail_put:
 66	put_user_ns(ns->user_ns);
 67	ns_free_inum(&ns->ns);
 68fail_free:
 69	kfree(ns);
 70fail_dec:
 71	dec_ipc_namespaces(ucounts);
 72fail:
 73	return ERR_PTR(err);
 74}
 75
 76struct ipc_namespace *copy_ipcs(unsigned long flags,
 77	struct user_namespace *user_ns, struct ipc_namespace *ns)
 78{
 79	if (!(flags & CLONE_NEWIPC))
 80		return get_ipc_ns(ns);
 81	return create_ipc_ns(user_ns, ns);
 82}
 83
 84/*
 85 * free_ipcs - free all ipcs of one type
 86 * @ns:   the namespace to remove the ipcs from
 87 * @ids:  the table of ipcs to free
 88 * @free: the function called to free each individual ipc
 89 *
 90 * Called for each kind of ipc when an ipc_namespace exits.
 91 */
 92void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
 93	       void (*free)(struct ipc_namespace *, struct kern_ipc_perm *))
 94{
 95	struct kern_ipc_perm *perm;
 96	int next_id;
 97	int total, in_use;
 98
 99	down_write(&ids->rwsem);
100
101	in_use = ids->in_use;
102
103	for (total = 0, next_id = 0; total < in_use; next_id++) {
104		perm = idr_find(&ids->ipcs_idr, next_id);
105		if (perm == NULL)
106			continue;
107		rcu_read_lock();
108		ipc_lock_object(perm);
109		free(ns, perm);
110		total++;
111	}
112	up_write(&ids->rwsem);
113}
114
115static void free_ipc_ns(struct ipc_namespace *ns)
116{
 
 
 
 
117	sem_exit_ns(ns);
118	msg_exit_ns(ns);
119	shm_exit_ns(ns);
120
 
 
 
121	dec_ipc_namespaces(ns->ucounts);
122	put_user_ns(ns->user_ns);
123	ns_free_inum(&ns->ns);
124	kfree(ns);
125}
126
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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 */
143void put_ipc_ns(struct ipc_namespace *ns)
144{
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}
152
153static inline struct ipc_namespace *to_ipc_ns(struct ns_common *ns)
154{
155	return container_of(ns, struct ipc_namespace, ns);
156}
157
158static struct ns_common *ipcns_get(struct task_struct *task)
159{
160	struct ipc_namespace *ns = NULL;
161	struct nsproxy *nsproxy;
162
163	task_lock(task);
164	nsproxy = task->nsproxy;
165	if (nsproxy)
166		ns = get_ipc_ns(nsproxy->ipc_ns);
167	task_unlock(task);
168
169	return ns ? &ns->ns : NULL;
170}
171
172static void ipcns_put(struct ns_common *ns)
173{
174	return put_ipc_ns(to_ipc_ns(ns));
175}
176
177static int ipcns_install(struct nsproxy *nsproxy, struct ns_common *new)
178{
 
179	struct ipc_namespace *ns = to_ipc_ns(new);
180	if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
181	    !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
182		return -EPERM;
183
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
191static struct user_namespace *ipcns_owner(struct ns_common *ns)
192{
193	return to_ipc_ns(ns)->user_ns;
194}
195
196const struct proc_ns_operations ipcns_operations = {
197	.name		= "ipc",
198	.type		= CLONE_NEWIPC,
199	.get		= ipcns_get,
200	.put		= ipcns_put,
201	.install	= ipcns_install,
202	.owner		= ipcns_owner,
203};

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * linux/ipc/namespace.c
  4 * Copyright (C) 2006 Pavel Emelyanov <xemul@openvz.org> OpenVZ, SWsoft Inc.
  5 */
  6
  7#include <linux/ipc.h>
  8#include <linux/msg.h>
  9#include <linux/ipc_namespace.h>
 10#include <linux/rcupdate.h>
 11#include <linux/nsproxy.h>
 12#include <linux/slab.h>
 13#include <linux/cred.h>
 14#include <linux/fs.h>
 15#include <linux/mount.h>
 16#include <linux/user_namespace.h>
 17#include <linux/proc_ns.h>
 18#include <linux/sched/task.h>
 19
 20#include "util.h"
 21
 22static struct ucounts *inc_ipc_namespaces(struct user_namespace *ns)
 23{
 24	return inc_ucount(ns, current_euid(), UCOUNT_IPC_NAMESPACES);
 25}
 26
 27static void dec_ipc_namespaces(struct ucounts *ucounts)
 28{
 29	dec_ucount(ucounts, UCOUNT_IPC_NAMESPACES);
 30}
 31
 32static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
 33					   struct ipc_namespace *old_ns)
 34{
 35	struct ipc_namespace *ns;
 36	struct ucounts *ucounts;
 37	int err;
 38
 39	err = -ENOSPC;
 40	ucounts = inc_ipc_namespaces(user_ns);
 41	if (!ucounts)
 42		goto fail;
 43
 44	err = -ENOMEM;
 45	ns = kzalloc(sizeof(struct ipc_namespace), GFP_KERNEL_ACCOUNT);
 46	if (ns == NULL)
 47		goto fail_dec;
 48
 49	err = ns_alloc_inum(&ns->ns);
 50	if (err)
 51		goto fail_free;
 52	ns->ns.ops = &ipcns_operations;
 53
 54	refcount_set(&ns->ns.count, 1);
 55	ns->user_ns = get_user_ns(user_ns);
 56	ns->ucounts = ucounts;
 57
 58	err = mq_init_ns(ns);
 59	if (err)
 60		goto fail_put;
 61
 62	err = -ENOMEM;
 63	if (!setup_mq_sysctls(ns))
 64		goto fail_put;
 65
 66	if (!setup_ipc_sysctls(ns))
 67		goto fail_mq;
 68
 69	err = msg_init_ns(ns);
 70	if (err)
 71		goto fail_put;
 72
 73	sem_init_ns(ns);
 
 74	shm_init_ns(ns);
 75
 76	return ns;
 77
 78fail_mq:
 79	retire_mq_sysctls(ns);
 80
 81fail_put:
 82	put_user_ns(ns->user_ns);
 83	ns_free_inum(&ns->ns);
 84fail_free:
 85	kfree(ns);
 86fail_dec:
 87	dec_ipc_namespaces(ucounts);
 88fail:
 89	return ERR_PTR(err);
 90}
 91
 92struct ipc_namespace *copy_ipcs(unsigned long flags,
 93	struct user_namespace *user_ns, struct ipc_namespace *ns)
 94{
 95	if (!(flags & CLONE_NEWIPC))
 96		return get_ipc_ns(ns);
 97	return create_ipc_ns(user_ns, ns);
 98}
 99
100/*
101 * free_ipcs - free all ipcs of one type
102 * @ns:   the namespace to remove the ipcs from
103 * @ids:  the table of ipcs to free
104 * @free: the function called to free each individual ipc
105 *
106 * Called for each kind of ipc when an ipc_namespace exits.
107 */
108void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
109	       void (*free)(struct ipc_namespace *, struct kern_ipc_perm *))
110{
111	struct kern_ipc_perm *perm;
112	int next_id;
113	int total, in_use;
114
115	down_write(&ids->rwsem);
116
117	in_use = ids->in_use;
118
119	for (total = 0, next_id = 0; total < in_use; next_id++) {
120		perm = idr_find(&ids->ipcs_idr, next_id);
121		if (perm == NULL)
122			continue;
123		rcu_read_lock();
124		ipc_lock_object(perm);
125		free(ns, perm);
126		total++;
127	}
128	up_write(&ids->rwsem);
129}
130
131static void free_ipc_ns(struct ipc_namespace *ns)
132{
133	/* mq_put_mnt() waits for a grace period as kern_unmount()
134	 * uses synchronize_rcu().
135	 */
136	mq_put_mnt(ns);
137	sem_exit_ns(ns);
138	msg_exit_ns(ns);
139	shm_exit_ns(ns);
140
141	retire_mq_sysctls(ns);
142	retire_ipc_sysctls(ns);
143
144	dec_ipc_namespaces(ns->ucounts);
145	put_user_ns(ns->user_ns);
146	ns_free_inum(&ns->ns);
147	kfree(ns);
148}
149
150static LLIST_HEAD(free_ipc_list);
151static void free_ipc(struct work_struct *unused)
152{
153	struct llist_node *node = llist_del_all(&free_ipc_list);
154	struct ipc_namespace *n, *t;
155
156	llist_for_each_entry_safe(n, t, node, mnt_llist)
157		free_ipc_ns(n);
158}
159
160/*
161 * The work queue is used to avoid the cost of synchronize_rcu in kern_unmount.
162 */
163static DECLARE_WORK(free_ipc_work, free_ipc);
164
165/*
166 * put_ipc_ns - drop a reference to an ipc namespace.
167 * @ns: the namespace to put
168 *
169 * If this is the last task in the namespace exiting, and
170 * it is dropping the refcount to 0, then it can race with
171 * a task in another ipc namespace but in a mounts namespace
172 * which has this ipcns's mqueuefs mounted, doing some action
173 * with one of the mqueuefs files.  That can raise the refcount.
174 * So dropping the refcount, and raising the refcount when
175 * accessing it through the VFS, are protected with mq_lock.
176 *
177 * (Clearly, a task raising the refcount on its own ipc_ns
178 * needn't take mq_lock since it can't race with the last task
179 * in the ipcns exiting).
180 */
181void put_ipc_ns(struct ipc_namespace *ns)
182{
183	if (refcount_dec_and_lock(&ns->ns.count, &mq_lock)) {
184		mq_clear_sbinfo(ns);
185		spin_unlock(&mq_lock);
186
187		if (llist_add(&ns->mnt_llist, &free_ipc_list))
188			schedule_work(&free_ipc_work);
189	}
190}
191
192static inline struct ipc_namespace *to_ipc_ns(struct ns_common *ns)
193{
194	return container_of(ns, struct ipc_namespace, ns);
195}
196
197static struct ns_common *ipcns_get(struct task_struct *task)
198{
199	struct ipc_namespace *ns = NULL;
200	struct nsproxy *nsproxy;
201
202	task_lock(task);
203	nsproxy = task->nsproxy;
204	if (nsproxy)
205		ns = get_ipc_ns(nsproxy->ipc_ns);
206	task_unlock(task);
207
208	return ns ? &ns->ns : NULL;
209}
210
211static void ipcns_put(struct ns_common *ns)
212{
213	return put_ipc_ns(to_ipc_ns(ns));
214}
215
216static int ipcns_install(struct nsset *nsset, struct ns_common *new)
217{
218	struct nsproxy *nsproxy = nsset->nsproxy;
219	struct ipc_namespace *ns = to_ipc_ns(new);
220	if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
221	    !ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN))
222		return -EPERM;
223
 
 
224	put_ipc_ns(nsproxy->ipc_ns);
225	nsproxy->ipc_ns = get_ipc_ns(ns);
226	return 0;
227}
228
229static struct user_namespace *ipcns_owner(struct ns_common *ns)
230{
231	return to_ipc_ns(ns)->user_ns;
232}
233
234const struct proc_ns_operations ipcns_operations = {
235	.name		= "ipc",
236	.type		= CLONE_NEWIPC,
237	.get		= ipcns_get,
238	.put		= ipcns_put,
239	.install	= ipcns_install,
240	.owner		= ipcns_owner,
241};