/*
 * linux/ipc/namespace.c
 * Copyright (C) 2006 Pavel Emelyanov <xemul@openvz.org> OpenVZ, SWsoft Inc.
 */

#include <linux/ipc.h>
#include <linux/msg.h>
#include <linux/ipc_namespace.h>
#include <linux/rcupdate.h>
#include <linux/nsproxy.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/user_namespace.h>
#include <linux/proc_ns.h>

#include "util.h"

static struct ucounts *inc_ipc_namespaces(struct user_namespace *ns)
{
	return inc_ucount(ns, current_euid(), UCOUNT_IPC_NAMESPACES);
}

static void dec_ipc_namespaces(struct ucounts *ucounts)
{
	dec_ucount(ucounts, UCOUNT_IPC_NAMESPACES);
}

static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
					   struct ipc_namespace *old_ns)
{
	struct ipc_namespace *ns;
	struct ucounts *ucounts;
	int err;

	err = -ENOSPC;
	ucounts = inc_ipc_namespaces(user_ns);
	if (!ucounts)
		goto fail;

	err = -ENOMEM;
	ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
	if (ns == NULL)
		goto fail_dec;

	err = ns_alloc_inum(&ns->ns);
	if (err)
		goto fail_free;
	ns->ns.ops = &ipcns_operations;

	atomic_set(&ns->count, 1);
	ns->user_ns = get_user_ns(user_ns);
	ns->ucounts = ucounts;

	err = mq_init_ns(ns);
	if (err)
		goto fail_put;

	sem_init_ns(ns);
	msg_init_ns(ns);
	shm_init_ns(ns);

	return ns;

fail_put:
	put_user_ns(ns->user_ns);
	ns_free_inum(&ns->ns);
fail_free:
	kfree(ns);
fail_dec:
	dec_ipc_namespaces(ucounts);
fail:
	return ERR_PTR(err);
}

struct ipc_namespace *copy_ipcs(unsigned long flags,
	struct user_namespace *user_ns, struct ipc_namespace *ns)
{
	if (!(flags & CLONE_NEWIPC))
		return get_ipc_ns(ns);
	return create_ipc_ns(user_ns, ns);
}

/*
 * free_ipcs - free all ipcs of one type
 * @ns:   the namespace to remove the ipcs from
 * @ids:  the table of ipcs to free
 * @free: the function called to free each individual ipc
 *
 * Called for each kind of ipc when an ipc_namespace exits.
 */
void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
	       void (*free)(struct ipc_namespace *, struct kern_ipc_perm *))
{
	struct kern_ipc_perm *perm;
	int next_id;
	int total, in_use;

	down_write(&ids->rwsem);

	in_use = ids->in_use;

	for (total = 0, next_id = 0; total < in_use; next_id++) {
		perm = idr_find(&ids->ipcs_idr, next_id);
		if (perm == NULL)
			continue;
		rcu_read_lock();
		ipc_lock_object(perm);
		free(ns, perm);
		total++;
	}
	up_write(&ids->rwsem);
}

static void free_ipc_ns(struct ipc_namespace *ns)
{
	sem_exit_ns(ns);
	msg_exit_ns(ns);
	shm_exit_ns(ns);

	dec_ipc_namespaces(ns->ucounts);
	put_user_ns(ns->user_ns);
	ns_free_inum(&ns->ns);
	kfree(ns);
}

/*
 * put_ipc_ns - drop a reference to an ipc namespace.
 * @ns: the namespace to put
 *
 * If this is the last task in the namespace exiting, and
 * it is dropping the refcount to 0, then it can race with
 * a task in another ipc namespace but in a mounts namespace
 * which has this ipcns's mqueuefs mounted, doing some action
 * with one of the mqueuefs files.  That can raise the refcount.
 * So dropping the refcount, and raising the refcount when
 * accessing it through the VFS, are protected with mq_lock.
 *
 * (Clearly, a task raising the refcount on its own ipc_ns
 * needn't take mq_lock since it can't race with the last task
 * in the ipcns exiting).
 */
void put_ipc_ns(struct ipc_namespace *ns)
{
	if (atomic_dec_and_lock(&ns->count, &mq_lock)) {
		mq_clear_sbinfo(ns);
		spin_unlock(&mq_lock);
		mq_put_mnt(ns);
		free_ipc_ns(ns);
	}
}

static inline struct ipc_namespace *to_ipc_ns(struct ns_common *ns)
{
	return container_of(ns, struct ipc_namespace, ns);
}

static struct ns_common *ipcns_get(struct task_struct *task)
{
	struct ipc_namespace *ns = NULL;
	struct nsproxy *nsproxy;

	task_lock(task);
	nsproxy = task->nsproxy;
	if (nsproxy)
		ns = get_ipc_ns(nsproxy->ipc_ns);
	task_unlock(task);

	return ns ? &ns->ns : NULL;
}

static void ipcns_put(struct ns_common *ns)
{
	return put_ipc_ns(to_ipc_ns(ns));
}

static int ipcns_install(struct nsproxy *nsproxy, struct ns_common *new)
{
	struct ipc_namespace *ns = to_ipc_ns(new);
	if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
	    !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
		return -EPERM;

	/* Ditch state from the old ipc namespace */
	exit_sem(current);
	put_ipc_ns(nsproxy->ipc_ns);
	nsproxy->ipc_ns = get_ipc_ns(ns);
	return 0;
}

static struct user_namespace *ipcns_owner(struct ns_common *ns)
{
	return to_ipc_ns(ns)->user_ns;
}

const struct proc_ns_operations ipcns_operations = {
	.name		= "ipc",
	.type		= CLONE_NEWIPC,
	.get		= ipcns_get,
	.put		= ipcns_put,
	.install	= ipcns_install,
	.owner		= ipcns_owner,
};
89f92bdaf072a648293db</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/?id=6dab07df555b652d8d989348b2ce04498d7f9a70'>6dab07df555b652d8d989348b2ce04498d7f9a70</a> (<a href='/cgit.cgi/linux/net-next.git/diff/?id=d443a0aa3a291e5f78072f2fa464e03bc83fafad&amp;id2=6dab07df555b652d8d989348b2ce04498d7f9a70'>diff</a>)</td></tr></table>
<div class='commit-subject'>HID: hid-sensor-hub: clear memory to avoid random data</div><div class='commit-msg'>When user tried to read some fields like hysteresis from IIO sysfs on some
systems, it fails. The reason is that this field is a byte field and caller
of sensor_hub_get_feature() passes a buffer of 4 bytes. Here the function
sensor_hub_get_feature() copies the single byte from the report to the
caller buffer and returns "1" as the number of bytes copied. So caller
can use the return value.

But this is done by multiple callers, so if we just change the
sensor_hub_get_feature so that caller buffer is initialized with 0s
then we don't to change all functions.

Signed-off-by: Song Hongyan &lt;hongyan.song@intel.com&gt;
Acked-by: Jonathan Cameron &lt;jic23@kernel.org&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=d443a0aa3a291e5f78072f2fa464e03bc83fafad'>Diffstat</a></div><table summary='diffstat' class='diffstat'>