--- /dev/null
+/*
+ * Copyright (C) 2013-2015 Kay Sievers
+ * Copyright (C) 2013-2015 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+ * Copyright (C) 2013-2015 Daniel Mack <daniel@zonque.org>
+ * Copyright (C) 2013-2015 David Herrmann <dh.herrmann@gmail.com>
+ * Copyright (C) 2013-2015 Linux Foundation
+ * Copyright (C) 2014-2015 Djalal Harouni <tixxdz@opendz.org>
+ *
+ * kdbus is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License as published by the
+ * Free Software Foundation; either version 2.1 of the License, or (at
+ * your option) any later version.
+ */
+
+#include <linux/audit.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/fs_struct.h>
+#include <linux/hashtable.h>
+#include <linux/idr.h>
+#include <linux/init.h>
+#include <linux/math64.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/path.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/shmem_fs.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+#include <linux/uio.h>
+
+#include "bus.h"
+#include "connection.h"
+#include "endpoint.h"
+#include "handle.h"
+#include "match.h"
+#include "message.h"
+#include "metadata.h"
+#include "names.h"
+#include "domain.h"
+#include "item.h"
+#include "notify.h"
+#include "policy.h"
+#include "pool.h"
+#include "reply.h"
+#include "util.h"
+#include "queue.h"
+
+#define KDBUS_CONN_ACTIVE_BIAS (INT_MIN + 2)
+#define KDBUS_CONN_ACTIVE_NEW (INT_MIN + 1)
+
+static struct kdbus_conn *kdbus_conn_new(struct kdbus_ep *ep, bool privileged,
+ struct kdbus_cmd_hello *hello,
+ const char *name,
+ const struct kdbus_creds *creds,
+ const struct kdbus_pids *pids,
+ const char *seclabel,
+ const char *conn_description)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ static struct lock_class_key __key;
+#endif
+ struct kdbus_pool_slice *slice = NULL;
+ struct kdbus_bus *bus = ep->bus;
+ struct kdbus_conn *conn;
+ u64 attach_flags_send;
+ u64 attach_flags_recv;
+ u64 items_size = 0;
+ bool is_policy_holder;
+ bool is_activator;
+ bool is_monitor;
+ struct kvec kvec;
+ int ret;
+
+ struct {
+ u64 size;
+ u64 type;
+ struct kdbus_bloom_parameter bloom;
+ } bloom_item;
+
+ is_monitor = hello->flags & KDBUS_HELLO_MONITOR;
+ is_activator = hello->flags & KDBUS_HELLO_ACTIVATOR;
+ is_policy_holder = hello->flags & KDBUS_HELLO_POLICY_HOLDER;
+
+ if (!hello->pool_size || !IS_ALIGNED(hello->pool_size, PAGE_SIZE))
+ return ERR_PTR(-EINVAL);
+ if (is_monitor + is_activator + is_policy_holder > 1)
+ return ERR_PTR(-EINVAL);
+ if (name && !is_activator && !is_policy_holder)
+ return ERR_PTR(-EINVAL);
+ if (!name && (is_activator || is_policy_holder))
+ return ERR_PTR(-EINVAL);
+ if (name && !kdbus_name_is_valid(name, true))
+ return ERR_PTR(-EINVAL);
+ if (is_monitor && ep->user)
+ return ERR_PTR(-EOPNOTSUPP);
+ if (!privileged && (is_activator || is_policy_holder || is_monitor))
+ return ERR_PTR(-EPERM);
+ if ((creds || pids || seclabel) && !privileged)
+ return ERR_PTR(-EPERM);
+
+ ret = kdbus_sanitize_attach_flags(hello->attach_flags_send,
+ &attach_flags_send);
+ if (ret < 0)
+ return ERR_PTR(ret);
+
+ ret = kdbus_sanitize_attach_flags(hello->attach_flags_recv,
+ &attach_flags_recv);
+ if (ret < 0)
+ return ERR_PTR(ret);
+
+ /* The attach flags must always satisfy the bus requirements. */
+ if (bus->attach_flags_req & ~attach_flags_send)
+ return ERR_PTR(-ECONNREFUSED);
+
+ conn = kzalloc(sizeof(*conn), GFP_KERNEL);
+ if (!conn)
+ return ERR_PTR(-ENOMEM);
+
+ kref_init(&conn->kref);
+ atomic_set(&conn->active, KDBUS_CONN_ACTIVE_NEW);
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ lockdep_init_map(&conn->dep_map, "s_active", &__key, 0);
+#endif
+ mutex_init(&conn->lock);
+ INIT_LIST_HEAD(&conn->names_list);
+ INIT_LIST_HEAD(&conn->names_queue_list);
+ INIT_LIST_HEAD(&conn->reply_list);
+ atomic_set(&conn->name_count, 0);
+ atomic_set(&conn->request_count, 0);
+ atomic_set(&conn->lost_count, 0);
+ INIT_DELAYED_WORK(&conn->work, kdbus_reply_list_scan_work);
+ conn->cred = get_current_cred();
+ init_waitqueue_head(&conn->wait);
+ kdbus_queue_init(&conn->queue);
+ conn->privileged = privileged;
+ conn->ep = kdbus_ep_ref(ep);
+ conn->id = atomic64_inc_return(&bus->domain->last_id);
+ conn->flags = hello->flags;
+ atomic64_set(&conn->attach_flags_send, attach_flags_send);
+ atomic64_set(&conn->attach_flags_recv, attach_flags_recv);
+ INIT_LIST_HEAD(&conn->monitor_entry);
+
+ if (conn_description) {
+ conn->description = kstrdup(conn_description, GFP_KERNEL);
+ if (!conn->description) {
+ ret = -ENOMEM;
+ goto exit_unref;
+ }
+ }
+
+ conn->pool = kdbus_pool_new(conn->description, hello->pool_size);
+ if (IS_ERR(conn->pool)) {
+ ret = PTR_ERR(conn->pool);
+ conn->pool = NULL;
+ goto exit_unref;
+ }
+
+ conn->match_db = kdbus_match_db_new();
+ if (IS_ERR(conn->match_db)) {
+ ret = PTR_ERR(conn->match_db);
+ conn->match_db = NULL;
+ goto exit_unref;
+ }
+
+ /* return properties of this connection to the caller */
+ hello->bus_flags = bus->bus_flags;
+ hello->id = conn->id;
+
+ BUILD_BUG_ON(sizeof(bus->id128) != sizeof(hello->id128));
+ memcpy(hello->id128, bus->id128, sizeof(hello->id128));
+
+ conn->meta = kdbus_meta_proc_new();
+ if (IS_ERR(conn->meta)) {
+ ret = PTR_ERR(conn->meta);
+ conn->meta = NULL;
+ goto exit_unref;
+ }
+
+ /* privileged processes can impersonate somebody else */
+ if (creds || pids || seclabel) {
+ ret = kdbus_meta_proc_fake(conn->meta, creds, pids, seclabel);
+ if (ret < 0)
+ goto exit_unref;
+
+ conn->faked_meta = true;
+ } else {
+ ret = kdbus_meta_proc_collect(conn->meta,
+ KDBUS_ATTACH_CREDS |
+ KDBUS_ATTACH_PIDS |
+ KDBUS_ATTACH_AUXGROUPS |
+ KDBUS_ATTACH_TID_COMM |
+ KDBUS_ATTACH_PID_COMM |
+ KDBUS_ATTACH_EXE |
+ KDBUS_ATTACH_CMDLINE |
+ KDBUS_ATTACH_CGROUP |
+ KDBUS_ATTACH_CAPS |
+ KDBUS_ATTACH_SECLABEL |
+ KDBUS_ATTACH_AUDIT);
+ if (ret < 0)
+ goto exit_unref;
+ }
+
+ /*
+ * Account the connection against the current user (UID), or for
+ * custom endpoints use the anonymous user assigned to the endpoint.
+ * Note that limits are always accounted against the real UID, not
+ * the effective UID (cred->user always points to the accounting of
+ * cred->uid, not cred->euid).
+ */
+ if (ep->user) {
+ conn->user = kdbus_user_ref(ep->user);
+ } else {
+ conn->user = kdbus_user_lookup(ep->bus->domain, current_uid());
+ if (IS_ERR(conn->user)) {
+ ret = PTR_ERR(conn->user);
+ conn->user = NULL;
+ goto exit_unref;
+ }
+ }
+
+ if (atomic_inc_return(&conn->user->connections) > KDBUS_USER_MAX_CONN) {
+ /* decremented by destructor as conn->user is valid */
+ ret = -EMFILE;
+ goto exit_unref;
+ }
+
+ bloom_item.size = sizeof(bloom_item);
+ bloom_item.type = KDBUS_ITEM_BLOOM_PARAMETER;
+ bloom_item.bloom = bus->bloom;
+ kdbus_kvec_set(&kvec, &bloom_item, bloom_item.size, &items_size);
+
+ slice = kdbus_pool_slice_alloc(conn->pool, items_size, false);
+ if (IS_ERR(slice)) {
+ ret = PTR_ERR(slice);
+ slice = NULL;
+ goto exit_unref;
+ }
+
+ ret = kdbus_pool_slice_copy_kvec(slice, 0, &kvec, 1, items_size);
+ if (ret < 0)
+ goto exit_unref;
+
+ kdbus_pool_slice_publish(slice, &hello->offset, &hello->items_size);
+ kdbus_pool_slice_release(slice);
+
+ return conn;
+
+exit_unref:
+ kdbus_pool_slice_release(slice);
+ kdbus_conn_unref(conn);
+ return ERR_PTR(ret);
+}
+
+static void __kdbus_conn_free(struct kref *kref)
+{
+ struct kdbus_conn *conn = container_of(kref, struct kdbus_conn, kref);
+
+ WARN_ON(kdbus_conn_active(conn));
+ WARN_ON(delayed_work_pending(&conn->work));
+ WARN_ON(!list_empty(&conn->queue.msg_list));
+ WARN_ON(!list_empty(&conn->names_list));
+ WARN_ON(!list_empty(&conn->names_queue_list));
+ WARN_ON(!list_empty(&conn->reply_list));
+
+ if (conn->user) {
+ atomic_dec(&conn->user->connections);
+ kdbus_user_unref(conn->user);
+ }
+
+ kdbus_meta_proc_unref(conn->meta);
+ kdbus_match_db_free(conn->match_db);
+ kdbus_pool_free(conn->pool);
+ kdbus_ep_unref(conn->ep);
+ put_cred(conn->cred);
+ kfree(conn->description);
+ kfree(conn->quota);
+ kfree(conn);
+}
+
+/**
+ * kdbus_conn_ref() - take a connection reference
+ * @conn: Connection, may be %NULL
+ *
+ * Return: the connection itself
+ */
+struct kdbus_conn *kdbus_conn_ref(struct kdbus_conn *conn)
+{
+ if (conn)
+ kref_get(&conn->kref);
+ return conn;
+}
+
+/**
+ * kdbus_conn_unref() - drop a connection reference
+ * @conn: Connection (may be NULL)
+ *
+ * When the last reference is dropped, the connection's internal structure
+ * is freed.
+ *
+ * Return: NULL
+ */
+struct kdbus_conn *kdbus_conn_unref(struct kdbus_conn *conn)
+{
+ if (conn)
+ kref_put(&conn->kref, __kdbus_conn_free);
+ return NULL;
+}
+
+/**
+ * kdbus_conn_active() - connection is not disconnected
+ * @conn: Connection to check
+ *
+ * Return true if the connection was not disconnected, yet. Note that a
+ * connection might be disconnected asynchronously, unless you hold the
+ * connection lock. If that's not suitable for you, see kdbus_conn_acquire() to
+ * suppress connection shutdown for a short period.
+ *
+ * Return: true if the connection is still active
+ */
+bool kdbus_conn_active(const struct kdbus_conn *conn)
+{
+ return atomic_read(&conn->active) >= 0;
+}
+
+/**
+ * kdbus_conn_acquire() - acquire an active connection reference
+ * @conn: Connection
+ *
+ * Users can close a connection via KDBUS_BYEBYE (or by destroying the
+ * endpoint/bus/...) at any time. Whenever this happens, we should deny any
+ * user-visible action on this connection and signal ECONNRESET instead.
+ * To avoid testing for connection availability everytime you take the
+ * connection-lock, you can acquire a connection for short periods.
+ *
+ * By calling kdbus_conn_acquire(), you gain an "active reference" to the
+ * connection. You must also hold a regular reference at any time! As long as
+ * you hold the active-ref, the connection will not be shut down. However, if
+ * the connection was shut down, you can never acquire an active-ref again.
+ *
+ * kdbus_conn_disconnect() disables the connection and then waits for all active
+ * references to be dropped. It will also wake up any pending operation.
+ * However, you must not sleep for an indefinite period while holding an
+ * active-reference. Otherwise, kdbus_conn_disconnect() might stall. If you need
+ * to sleep for an indefinite period, either release the reference and try to
+ * acquire it again after waking up, or make kdbus_conn_disconnect() wake up
+ * your wait-queue.
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int kdbus_conn_acquire(struct kdbus_conn *conn)
+{
+ if (!atomic_inc_unless_negative(&conn->active))
+ return -ECONNRESET;
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ rwsem_acquire_read(&conn->dep_map, 0, 1, _RET_IP_);
+#endif
+
+ return 0;
+}
+
+/**
+ * kdbus_conn_release() - release an active connection reference
+ * @conn: Connection
+ *
+ * This releases an active reference that has been acquired via
+ * kdbus_conn_acquire(). If the connection was already disabled and this is the
+ * last active-ref that is dropped, the disconnect-waiter will be woken up and
+ * properly close the connection.
+ */
+void kdbus_conn_release(struct kdbus_conn *conn)
+{
+ int v;
+
+ if (!conn)
+ return;
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ rwsem_release(&conn->dep_map, 1, _RET_IP_);
+#endif
+
+ v = atomic_dec_return(&conn->active);
+ if (v != KDBUS_CONN_ACTIVE_BIAS)
+ return;
+
+ wake_up_all(&conn->wait);
+}
+
+static int kdbus_conn_connect(struct kdbus_conn *conn, const char *name)
+{
+ struct kdbus_ep *ep = conn->ep;
+ struct kdbus_bus *bus = ep->bus;
+ int ret;
+
+ if (WARN_ON(atomic_read(&conn->active) != KDBUS_CONN_ACTIVE_NEW))
+ return -EALREADY;
+
+ /* make sure the ep-node is active while we add our connection */
+ if (!kdbus_node_acquire(&ep->node))
+ return -ESHUTDOWN;
+
+ /* lock order: domain -> bus -> ep -> names -> conn */
+ mutex_lock(&ep->lock);
+ down_write(&bus->conn_rwlock);
+
+ /* link into monitor list */
+ if (kdbus_conn_is_monitor(conn))
+ list_add_tail(&conn->monitor_entry, &bus->monitors_list);
+
+ /* link into bus and endpoint */
+ list_add_tail(&conn->ep_entry, &ep->conn_list);
+ hash_add(bus->conn_hash, &conn->hentry, conn->id);
+
+ /* enable lookups and acquire active ref */
+ atomic_set(&conn->active, 1);
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ rwsem_acquire_read(&conn->dep_map, 0, 1, _RET_IP_);
+#endif
+
+ up_write(&bus->conn_rwlock);
+ mutex_unlock(&ep->lock);
+
+ kdbus_node_release(&ep->node);
+
+ /*
+ * Notify subscribers about the new active connection, unless it is
+ * a monitor. Monitors are invisible on the bus, can't be addressed
+ * directly, and won't cause any notifications.
+ */
+ if (!kdbus_conn_is_monitor(conn)) {
+ ret = kdbus_notify_id_change(conn->ep->bus, KDBUS_ITEM_ID_ADD,
+ conn->id, conn->flags);
+ if (ret < 0)
+ goto exit_disconnect;
+ }
+
+ if (kdbus_conn_is_activator(conn)) {
+ u64 flags = KDBUS_NAME_ACTIVATOR;
+
+ if (WARN_ON(!name)) {
+ ret = -EINVAL;
+ goto exit_disconnect;
+ }
+
+ ret = kdbus_name_acquire(bus->name_registry, conn, name,
+ flags, NULL);
+ if (ret < 0)
+ goto exit_disconnect;
+ }
+
+ kdbus_conn_release(conn);
+ kdbus_notify_flush(bus);
+ return 0;
+
+exit_disconnect:
+ kdbus_conn_release(conn);
+ kdbus_conn_disconnect(conn, false);
+ return ret;
+}
+
+/**
+ * kdbus_conn_disconnect() - disconnect a connection
+ * @conn: The connection to disconnect
+ * @ensure_queue_empty: Flag to indicate if the call should fail in
+ * case the connection's message list is not
+ * empty
+ *
+ * If @ensure_msg_list_empty is true, and the connection has pending messages,
+ * -EBUSY is returned.
+ *
+ * Return: 0 on success, negative errno on failure
+ */
+int kdbus_conn_disconnect(struct kdbus_conn *conn, bool ensure_queue_empty)
+{
+ struct kdbus_queue_entry *entry, *tmp;
+ struct kdbus_bus *bus = conn->ep->bus;
+ struct kdbus_reply *r, *r_tmp;
+ struct kdbus_conn *c;
+ int i, v;
+
+ mutex_lock(&conn->lock);
+ v = atomic_read(&conn->active);
+ if (v == KDBUS_CONN_ACTIVE_NEW) {
+ /* was never connected */
+ mutex_unlock(&conn->lock);
+ return 0;
+ }
+ if (v < 0) {
+ /* already dead */
+ mutex_unlock(&conn->lock);
+ return -ECONNRESET;
+ }
+ if (ensure_queue_empty && !list_empty(&conn->queue.msg_list)) {
+ /* still busy */
+ mutex_unlock(&conn->lock);
+ return -EBUSY;
+ }
+
+ atomic_add(KDBUS_CONN_ACTIVE_BIAS, &conn->active);
+ mutex_unlock(&conn->lock);
+
+ wake_up_interruptible(&conn->wait);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ rwsem_acquire(&conn->dep_map, 0, 0, _RET_IP_);
+ if (atomic_read(&conn->active) != KDBUS_CONN_ACTIVE_BIAS)
+ lock_contended(&conn->dep_map, _RET_IP_);
+#endif
+
+ wait_event(conn->wait,
+ atomic_read(&conn->active) == KDBUS_CONN_ACTIVE_BIAS);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ lock_acquired(&conn->dep_map, _RET_IP_);
+ rwsem_release(&conn->dep_map, 1, _RET_IP_);
+#endif
+
+ cancel_delayed_work_sync(&conn->work);
+ kdbus_policy_remove_owner(&conn->ep->bus->policy_db, conn);
+
+ /* lock order: domain -> bus -> ep -> names -> conn */
+ mutex_lock(&conn->ep->lock);
+ down_write(&bus->conn_rwlock);
+
+ /* remove from bus and endpoint */
+ hash_del(&conn->hentry);
+ list_del(&conn->monitor_entry);
+ list_del(&conn->ep_entry);
+
+ up_write(&bus->conn_rwlock);
+ mutex_unlock(&conn->ep->lock);
+
+ /*
+ * Remove all names associated with this connection; this possibly
+ * moves queued messages back to the activator connection.
+ */
+ kdbus_name_release_all(bus->name_registry, conn);
+
+ /* if we die while other connections wait for our reply, notify them */
+ mutex_lock(&conn->lock);
+ list_for_each_entry_safe(entry, tmp, &conn->queue.msg_list, entry) {
+ if (entry->reply)
+ kdbus_notify_reply_dead(bus,
+ entry->reply->reply_dst->id,
+ entry->reply->cookie);
+ kdbus_queue_entry_free(entry);
+ }
+
+ list_for_each_entry_safe(r, r_tmp, &conn->reply_list, entry)
+ kdbus_reply_unlink(r);
+ mutex_unlock(&conn->lock);
+
+ /* lock order: domain -> bus -> ep -> names -> conn */
+ down_read(&bus->conn_rwlock);
+ hash_for_each(bus->conn_hash, i, c, hentry) {
+ mutex_lock(&c->lock);
+ list_for_each_entry_safe(r, r_tmp, &c->reply_list, entry) {
+ if (r->reply_src == conn) {
+ if (r->sync) {
+ kdbus_sync_reply_wakeup(r, -EPIPE);
+ kdbus_reply_unlink(r);
+ continue;
+ }
+
+ /* send a 'connection dead' notification */
+ kdbus_notify_reply_dead(bus, c->id, r->cookie);
+ kdbus_reply_unlink(r);
+ }
+ }
+ mutex_unlock(&c->lock);
+ }
+ up_read(&bus->conn_rwlock);
+
+ if (!kdbus_conn_is_monitor(conn))
+ kdbus_notify_id_change(bus, KDBUS_ITEM_ID_REMOVE,
+ conn->id, conn->flags);
+
+ kdbus_notify_flush(bus);
+
+ return 0;
+}
+
+/**
+ * kdbus_conn_has_name() - check if a connection owns a name
+ * @conn: Connection
+ * @name: Well-know name to check for
+ *
+ * The caller must hold the registry lock of conn->ep->bus.
+ *
+ * Return: true if the name is currently owned by the connection
+ */
+bool kdbus_conn_has_name(struct kdbus_conn *conn, const char *name)
+{
+ struct kdbus_name_entry *e;
+
+ lockdep_assert_held(&conn->ep->bus->name_registry->rwlock);
+
+ list_for_each_entry(e, &conn->names_list, conn_entry)
+ if (strcmp(e->name, name) == 0)
+ return true;
+
+ return false;
+}
+
+struct kdbus_quota {
+ uint32_t memory;
+ uint16_t msgs;
+ uint8_t fds;
+};
+
+/**
+ * kdbus_conn_quota_inc() - increase quota accounting
+ * @c: connection owning the quota tracking
+ * @u: user to account for (or NULL for kernel accounting)
+ * @memory: size of memory to account for
+ * @fds: number of FDs to account for
+ *
+ * This call manages the quotas on resource @c. That is, it's used if other
+ * users want to use the resources of connection @c, which so far only concerns
+ * the receive queue of the destination.
+ *
+ * This increases the quota-accounting for user @u by @memory bytes and @fds
+ * file descriptors. If the user has already reached the quota limits, this call
+ * will not do any accounting but return a negative error code indicating the
+ * failure.
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int kdbus_conn_quota_inc(struct kdbus_conn *c, struct kdbus_user *u,
+ size_t memory, size_t fds)
+{
+ struct kdbus_quota *quota;
+ size_t available, accounted;
+ unsigned int id;
+
+ /*
+ * Pool Layout:
+ * 50% of a pool is always owned by the connection. It is reserved for
+ * kernel queries, handling received messages and other tasks that are
+ * under control of the pool owner. The other 50% of the pool are used
+ * as incoming queue.
+ * As we optionally support user-space based policies, we need fair
+ * allocation schemes. Furthermore, resource utilization should be
+ * maximized, so only minimal resources stay reserved. However, we need
+ * to adapt to a dynamic number of users, as we cannot know how many
+ * users will talk to a connection. Therefore, the current allocations
+ * works like this:
+ * We limit the number of bytes in a destination's pool per sending
+ * user. The space available for a user is 33% of the unused pool space
+ * (whereas the space used by the user itself is also treated as
+ * 'unused'). This way, we favor users coming first, but keep enough
+ * pool space available for any following users. Given that messages are
+ * dequeued in FIFO order, this should balance nicely if the number of
+ * users grows. At the same time, this algorithm guarantees that the
+ * space available to a connection is reduced dynamically, the more
+ * concurrent users talk to a connection.
+ */
+
+ /* per user-accounting is expensive, so we keep state small */
+ BUILD_BUG_ON(sizeof(quota->memory) != 4);
+ BUILD_BUG_ON(sizeof(quota->msgs) != 2);
+ BUILD_BUG_ON(sizeof(quota->fds) != 1);
+ BUILD_BUG_ON(KDBUS_CONN_MAX_MSGS > U16_MAX);
+ BUILD_BUG_ON(KDBUS_CONN_MAX_FDS_PER_USER > U8_MAX);
+
+ id = u ? u->id : KDBUS_USER_KERNEL_ID;
+ if (id >= c->n_quota) {
+ unsigned int users;
+
+ users = max(KDBUS_ALIGN8(id) + 8, id);
+ quota = krealloc(c->quota, users * sizeof(*quota),
+ GFP_KERNEL | __GFP_ZERO);
+ if (!quota)
+ return -ENOMEM;
+
+ c->n_quota = users;
+ c->quota = quota;
+ }
+
+ quota = &c->quota[id];
+ kdbus_pool_accounted(c->pool, &available, &accounted);
+
+ /* half the pool is _always_ reserved for the pool owner */
+ available /= 2;
+
+ /*
+ * Pool owner slices are un-accounted slices; they can claim more
+ * than 50% of the queue. However, the slice we're dealing with here
+ * belong to the incoming queue, hence they are 'accounted' slices
+ * to which the 50%-limit applies.
+ */
+ if (available < accounted)
+ return -ENOBUFS;
+
+ /* 1/3 of the remaining space (including your own memory) */
+ available = (available - accounted + quota->memory) / 3;
+
+ if (available < quota->memory ||
+ available - quota->memory < memory ||
+ quota->memory + memory > U32_MAX)
+ return -ENOBUFS;
+ if (quota->msgs >= KDBUS_CONN_MAX_MSGS)
+ return -ENOBUFS;
+ if (quota->fds + fds < quota->fds ||
+ quota->fds + fds > KDBUS_CONN_MAX_FDS_PER_USER)
+ return -EMFILE;
+
+ quota->memory += memory;
+ quota->fds += fds;
+ ++quota->msgs;
+ return 0;
+}
+
+/**
+ * kdbus_conn_quota_dec() - decrease quota accounting
+ * @c: connection owning the quota tracking
+ * @u: user which was accounted for (or NULL for kernel accounting)
+ * @memory: size of memory which was accounted for
+ * @fds: number of FDs which were accounted for
+ *
+ * This does the reverse of kdbus_conn_quota_inc(). You have to release any
+ * accounted resources that you called kdbus_conn_quota_inc() for. However, you
+ * must not call kdbus_conn_quota_dec() if the accounting failed (that is,
+ * kdbus_conn_quota_inc() failed).
+ */
+void kdbus_conn_quota_dec(struct kdbus_conn *c, struct kdbus_user *u,
+ size_t memory, size_t fds)
+{
+ struct kdbus_quota *quota;
+ unsigned int id;
+
+ id = u ? u->id : KDBUS_USER_KERNEL_ID;
+ if (WARN_ON(id >= c->n_quota))
+ return;
+
+ quota = &c->quota[id];
+
+ if (!WARN_ON(quota->msgs == 0))
+ --quota->msgs;
+ if (!WARN_ON(quota->memory < memory))
+ quota->memory -= memory;
+ if (!WARN_ON(quota->fds < fds))
+ quota->fds -= fds;
+}
+
+/**
+ * kdbus_conn_lost_message() - handle lost messages
+ * @c: connection that lost a message
+ *
+ * kdbus is reliable. That means, we try hard to never lose messages. However,
+ * memory is limited, so we cannot rely on transmissions to never fail.
+ * Therefore, we use quota-limits to let callers know if there unicast message
+ * cannot be transmitted to a peer. This works fine for unicasts, but for
+ * broadcasts we cannot make the caller handle the transmission failure.
+ * Instead, we must let the destination know that it couldn't receive a
+ * broadcast.
+ * As this is an unlikely scenario, we keep it simple. A single lost-counter
+ * remembers the number of lost messages since the last call to RECV. The next
+ * message retrieval will notify the connection that it lost messages since the
+ * last message retrieval and thus should resync its state.
+ */
+void kdbus_conn_lost_message(struct kdbus_conn *c)
+{
+ if (atomic_inc_return(&c->lost_count) == 1)
+ wake_up_interruptible(&c->wait);
+}
+
+/* Callers should take the conn_dst lock */
+static struct kdbus_queue_entry *
+kdbus_conn_entry_make(struct kdbus_conn *conn_dst,
+ const struct kdbus_kmsg *kmsg,
+ struct kdbus_user *user)
+{
+ struct kdbus_queue_entry *entry;
+
+ /* The remote connection was disconnected */
+ if (!kdbus_conn_active(conn_dst))
+ return ERR_PTR(-ECONNRESET);
+
+ /*
+ * If the connection does not accept file descriptors but the message
+ * has some attached, refuse it.
+ *
+ * If this is a monitor connection, accept the message. In that
+ * case, all file descriptors will be set to -1 at receive time.
+ */
+ if (!kdbus_conn_is_monitor(conn_dst) &&
+ !(conn_dst->flags & KDBUS_HELLO_ACCEPT_FD) &&
+ kmsg->res && kmsg->res->fds_count > 0)
+ return ERR_PTR(-ECOMM);
+
+ entry = kdbus_queue_entry_new(conn_dst, kmsg, user);
+ if (IS_ERR(entry))
+ return entry;
+
+ return entry;
+}
+
+/*
+ * Synchronously responding to a message, allocate a queue entry
+ * and attach it to the reply tracking object.
+ * The connection's queue will never get to see it.
+ */
+static int kdbus_conn_entry_sync_attach(struct kdbus_conn *conn_dst,
+ const struct kdbus_kmsg *kmsg,
+ struct kdbus_reply *reply_wake)
+{
+ struct kdbus_queue_entry *entry;
+ int remote_ret;
+ int ret = 0;
+
+ mutex_lock(&reply_wake->reply_dst->lock);
+
+ /*
+ * If we are still waiting then proceed, allocate a queue
+ * entry and attach it to the reply object
+ */
+ if (reply_wake->waiting) {
+ entry = kdbus_conn_entry_make(conn_dst, kmsg,
+ reply_wake->reply_src->user);
+ if (IS_ERR(entry))
+ ret = PTR_ERR(entry);
+ else
+ /* Attach the entry to the reply object */
+ reply_wake->queue_entry = entry;
+ } else {
+ ret = -ECONNRESET;
+ }
+
+ /*
+ * Update the reply object and wake up remote peer only
+ * on appropriate return codes
+ *
+ * * -ECOMM: if the replying connection failed with -ECOMM
+ * then wakeup remote peer with -EREMOTEIO
+ *
+ * We do this to differenciate between -ECOMM errors
+ * from the original sender perspective:
+ * -ECOMM error during the sync send and
+ * -ECOMM error during the sync reply, this last
+ * one is rewritten to -EREMOTEIO
+ *
+ * * Wake up on all other return codes.
+ */
+ remote_ret = ret;
+
+ if (ret == -ECOMM)
+ remote_ret = -EREMOTEIO;
+
+ kdbus_sync_reply_wakeup(reply_wake, remote_ret);
+ kdbus_reply_unlink(reply_wake);
+ mutex_unlock(&reply_wake->reply_dst->lock);
+
+ return ret;
+}
+
+/**
+ * kdbus_conn_entry_insert() - enqueue a message into the receiver's pool
+ * @conn_src: The sending connection
+ * @conn_dst: The connection to queue into
+ * @kmsg: The kmsg to queue
+ * @reply: The reply tracker to attach to the queue entry
+ *
+ * Return: 0 on success. negative error otherwise.
+ */
+int kdbus_conn_entry_insert(struct kdbus_conn *conn_src,
+ struct kdbus_conn *conn_dst,
+ const struct kdbus_kmsg *kmsg,
+ struct kdbus_reply *reply)
+{
+ struct kdbus_queue_entry *entry;
+ int ret;
+
+ kdbus_conn_lock2(conn_src, conn_dst);
+
+ entry = kdbus_conn_entry_make(conn_dst, kmsg,
+ conn_src ? conn_src->user : NULL);
+ if (IS_ERR(entry)) {
+ ret = PTR_ERR(entry);
+ goto exit_unlock;
+ }
+
+ if (reply) {
+ kdbus_reply_link(reply);
+ if (!reply->sync)
+ schedule_delayed_work(&conn_src->work, 0);
+ }
+
+ kdbus_queue_entry_enqueue(entry, reply);
+ wake_up_interruptible(&conn_dst->wait);
+
+ ret = 0;
+
+exit_unlock:
+ kdbus_conn_unlock2(conn_src, conn_dst);
+ return ret;
+}
+
+static int kdbus_conn_wait_reply(struct kdbus_conn *conn_src,
+ struct kdbus_cmd_send *cmd_send,
+ struct file *ioctl_file,
+ struct file *cancel_fd,
+ struct kdbus_reply *reply_wait,
+ ktime_t expire)
+{
+ struct kdbus_queue_entry *entry;
+ struct poll_wqueues pwq = {};
+ int ret;
+
+ if (WARN_ON(!reply_wait))
+ return -EIO;
+
+ /*
+ * Block until the reply arrives. reply_wait is left untouched
+ * by the timeout scans that might be conducted for other,
+ * asynchronous replies of conn_src.
+ */
+
+ poll_initwait(&pwq);
+ poll_wait(ioctl_file, &conn_src->wait, &pwq.pt);
+
+ for (;;) {
+ /*
+ * Any of the following conditions will stop our synchronously
+ * blocking SEND command:
+ *
+ * a) The origin sender closed its connection
+ * b) The remote peer answered, setting reply_wait->waiting = 0
+ * c) The cancel FD was written to
+ * d) A signal was received
+ * e) The specified timeout was reached, and none of the above
+ * conditions kicked in.
+ */
+
+ /*
+ * We have already acquired an active reference when
+ * entering here, but another thread may call
+ * KDBUS_CMD_BYEBYE which does not acquire an active
+ * reference, therefore kdbus_conn_disconnect() will
+ * not wait for us.
+ */
+ if (!kdbus_conn_active(conn_src)) {
+ ret = -ECONNRESET;
+ break;
+ }
+
+ /*
+ * After the replying peer unset the waiting variable
+ * it will wake up us.
+ */
+ if (!reply_wait->waiting) {
+ ret = reply_wait->err;
+ break;
+ }
+
+ if (cancel_fd) {
+ unsigned int r;
+
+ r = cancel_fd->f_op->poll(cancel_fd, &pwq.pt);
+ if (r & POLLIN) {
+ ret = -ECANCELED;
+ break;
+ }
+ }
+
+ if (signal_pending(current)) {
+ ret = -EINTR;
+ break;
+ }
+
+ if (!poll_schedule_timeout(&pwq, TASK_INTERRUPTIBLE,
+ &expire, 0)) {
+ ret = -ETIMEDOUT;
+ break;
+ }
+
+ /*
+ * Reset the poll worker func, so the waitqueues are not
+ * added to the poll table again. We just reuse what we've
+ * collected earlier for further iterations.
+ */
+ init_poll_funcptr(&pwq.pt, NULL);
+ }
+
+ poll_freewait(&pwq);
+
+ if (ret == -EINTR) {
+ /*
+ * Interrupted system call. Unref the reply object, and pass
+ * the return value down the chain. Mark the reply as
+ * interrupted, so the cleanup work can remove it, but do not
+ * unlink it from the list. Once the syscall restarts, we'll
+ * pick it up and wait on it again.
+ */
+ mutex_lock(&conn_src->lock);
+ reply_wait->interrupted = true;
+ schedule_delayed_work(&conn_src->work, 0);
+ mutex_unlock(&conn_src->lock);
+
+ return -ERESTARTSYS;
+ }
+
+ mutex_lock(&conn_src->lock);
+ reply_wait->waiting = false;
+ entry = reply_wait->queue_entry;
+ if (entry) {
+ ret = kdbus_queue_entry_install(entry,
+ &cmd_send->reply.return_flags,
+ true);
+ kdbus_pool_slice_publish(entry->slice, &cmd_send->reply.offset,
+ &cmd_send->reply.msg_size);
+ kdbus_queue_entry_free(entry);
+ }
+ kdbus_reply_unlink(reply_wait);
+ mutex_unlock(&conn_src->lock);
+
+ return ret;
+}
+
+static int kdbus_pin_dst(struct kdbus_bus *bus,
+ struct kdbus_kmsg *kmsg,
+ struct kdbus_name_entry **out_name,
+ struct kdbus_conn **out_dst)
+{
+ struct kdbus_msg_resources *res = kmsg->res;
+ struct kdbus_name_entry *name = NULL;
+ struct kdbus_conn *dst = NULL;
+ struct kdbus_msg *msg = &kmsg->msg;
+ int ret;
+
+ if (WARN_ON(!res))
+ return -EINVAL;
+
+ lockdep_assert_held(&bus->name_registry->rwlock);
+
+ if (!res->dst_name) {
+ dst = kdbus_bus_find_conn_by_id(bus, msg->dst_id);
+ if (!dst)
+ return -ENXIO;
+
+ if (!kdbus_conn_is_ordinary(dst)) {
+ ret = -ENXIO;
+ goto error;
+ }
+ } else {
+ name = kdbus_name_lookup_unlocked(bus->name_registry,
+ res->dst_name);
+ if (!name)
+ return -ESRCH;
+
+ /*
+ * If both a name and a connection ID are given as destination
+ * of a message, check that the currently owning connection of
+ * the name matches the specified ID.
+ * This way, we allow userspace to send the message to a
+ * specific connection by ID only if the connection currently
+ * owns the given name.
+ */
+ if (msg->dst_id != KDBUS_DST_ID_NAME &&
+ msg->dst_id != name->conn->id)
+ return -EREMCHG;
+
+ if (!name->conn && name->activator)
+ dst = kdbus_conn_ref(name->activator);
+ else
+ dst = kdbus_conn_ref(name->conn);
+
+ if ((msg->flags & KDBUS_MSG_NO_AUTO_START) &&
+ kdbus_conn_is_activator(dst)) {
+ ret = -EADDRNOTAVAIL;
+ goto error;
+ }
+
+ /*
+ * Record the sequence number of the registered name; it will
+ * be passed on to the queue, in case messages addressed to a
+ * name need to be moved from or to an activator.
+ */
+ kmsg->dst_name_id = name->name_id;
+ }
+
+ *out_name = name;
+ *out_dst = dst;
+ return 0;
+
+error:
+ kdbus_conn_unref(dst);
+ return ret;
+}
+
+static int kdbus_conn_reply(struct kdbus_conn *src, struct kdbus_kmsg *kmsg)
+{
+ struct kdbus_name_entry *name = NULL;
+ struct kdbus_reply *reply, *wake = NULL;
+ struct kdbus_conn *dst = NULL;
+ struct kdbus_bus *bus = src->ep->bus;
+ u64 attach;
+ int ret;
+
+ if (WARN_ON(kmsg->msg.dst_id == KDBUS_DST_ID_BROADCAST) ||
+ WARN_ON(kmsg->msg.flags & KDBUS_MSG_EXPECT_REPLY) ||
+ WARN_ON(kmsg->msg.flags & KDBUS_MSG_SIGNAL))
+ return -EINVAL;
+
+ /* name-registry must be locked for lookup *and* collecting data */
+ down_read(&bus->name_registry->rwlock);
+
+ /* find and pin destination */
+
+ ret = kdbus_pin_dst(bus, kmsg, &name, &dst);
+ if (ret < 0)
+ goto exit;
+
+ mutex_lock(&dst->lock);
+ reply = kdbus_reply_find(src, dst, kmsg->msg.cookie_reply);
+ if (reply) {
+ if (reply->sync)
+ wake = kdbus_reply_ref(reply);
+ kdbus_reply_unlink(reply);
+ }
+ mutex_unlock(&dst->lock);
+
+ if (!reply) {
+ ret = -EPERM;
+ goto exit;
+ }
+
+ /* attach metadata */
+
+ attach = kdbus_meta_calc_attach_flags(src, dst);
+
+ if (!src->faked_meta) {
+ ret = kdbus_meta_proc_collect(kmsg->proc_meta, attach);
+ if (ret < 0)
+ goto exit;
+ }
+
+ ret = kdbus_meta_conn_collect(kmsg->conn_meta, kmsg, src, attach);
+ if (ret < 0)
+ goto exit;
+
+ /* send message */
+
+ kdbus_bus_eavesdrop(bus, src, kmsg);
+
+ if (wake)
+ ret = kdbus_conn_entry_sync_attach(dst, kmsg, wake);
+ else
+ ret = kdbus_conn_entry_insert(src, dst, kmsg, NULL);
+
+exit:
+ up_read(&bus->name_registry->rwlock);
+ kdbus_reply_unref(wake);
+ kdbus_conn_unref(dst);
+ return ret;
+}
+
+static struct kdbus_reply *kdbus_conn_call(struct kdbus_conn *src,
+ struct kdbus_kmsg *kmsg,
+ ktime_t exp)
+{
+ struct kdbus_name_entry *name = NULL;
+ struct kdbus_reply *wait = NULL;
+ struct kdbus_conn *dst = NULL;
+ struct kdbus_bus *bus = src->ep->bus;
+ u64 attach;
+ int ret;
+
+ if (WARN_ON(kmsg->msg.dst_id == KDBUS_DST_ID_BROADCAST) ||
+ WARN_ON(kmsg->msg.flags & KDBUS_MSG_SIGNAL) ||
+ WARN_ON(!(kmsg->msg.flags & KDBUS_MSG_EXPECT_REPLY)))
+ return ERR_PTR(-EINVAL);
+
+ /* resume previous wait-context, if available */
+
+ mutex_lock(&src->lock);
+ wait = kdbus_reply_find(NULL, src, kmsg->msg.cookie);
+ if (wait) {
+ if (wait->interrupted) {
+ kdbus_reply_ref(wait);
+ wait->interrupted = false;
+ } else {
+ wait = NULL;
+ }
+ }
+ mutex_unlock(&src->lock);
+
+ if (wait)
+ return wait;
+
+ if (ktime_compare(ktime_get(), exp) >= 0)
+ return ERR_PTR(-ETIMEDOUT);
+
+ /* name-registry must be locked for lookup *and* collecting data */
+ down_read(&bus->name_registry->rwlock);
+
+ /* find and pin destination */
+
+ ret = kdbus_pin_dst(bus, kmsg, &name, &dst);
+ if (ret < 0)
+ goto exit;
+
+ if (!kdbus_conn_policy_talk(src, current_cred(), dst)) {
+ ret = -EPERM;
+ goto exit;
+ }
+
+ wait = kdbus_reply_new(dst, src, &kmsg->msg, name, true);
+ if (IS_ERR(wait)) {
+ ret = PTR_ERR(wait);
+ wait = NULL;
+ goto exit;
+ }
+
+ /* attach metadata */
+
+ attach = kdbus_meta_calc_attach_flags(src, dst);
+
+ if (!src->faked_meta) {
+ ret = kdbus_meta_proc_collect(kmsg->proc_meta, attach);
+ if (ret < 0)
+ goto exit;
+ }
+
+ ret = kdbus_meta_conn_collect(kmsg->conn_meta, kmsg, src, attach);
+ if (ret < 0)
+ goto exit;
+
+ /* send message */
+
+ kdbus_bus_eavesdrop(bus, src, kmsg);
+
+ ret = kdbus_conn_entry_insert(src, dst, kmsg, wait);
+ if (ret < 0)
+ goto exit;
+
+ ret = 0;
+
+exit:
+ up_read(&bus->name_registry->rwlock);
+ if (ret < 0) {
+ kdbus_reply_unref(wait);
+ wait = ERR_PTR(ret);
+ }
+ kdbus_conn_unref(dst);
+ return wait;
+}
+
+static int kdbus_conn_unicast(struct kdbus_conn *src, struct kdbus_kmsg *kmsg)
+{
+ struct kdbus_name_entry *name = NULL;
+ struct kdbus_reply *wait = NULL;
+ struct kdbus_conn *dst = NULL;
+ struct kdbus_bus *bus = src->ep->bus;
+ bool is_signal = (kmsg->msg.flags & KDBUS_MSG_SIGNAL);
+ u64 attach;
+ int ret = 0;
+
+ if (WARN_ON(kmsg->msg.dst_id == KDBUS_DST_ID_BROADCAST) ||
+ WARN_ON(!(kmsg->msg.flags & KDBUS_MSG_EXPECT_REPLY) &&
+ kmsg->msg.cookie_reply != 0))
+ return -EINVAL;
+
+ /* name-registry must be locked for lookup *and* collecting data */
+ down_read(&bus->name_registry->rwlock);
+
+ /* find and pin destination */
+
+ ret = kdbus_pin_dst(bus, kmsg, &name, &dst);
+ if (ret < 0)
+ goto exit;
+
+ if (is_signal) {
+ /* like broadcasts we eavesdrop even if the msg is dropped */
+ kdbus_bus_eavesdrop(bus, src, kmsg);
+
+ /* drop silently if peer is not interested or not privileged */
+ if (!kdbus_match_db_match_kmsg(dst->match_db, src, kmsg) ||
+ !kdbus_conn_policy_talk(dst, NULL, src))
+ goto exit;
+ } else if (!kdbus_conn_policy_talk(src, current_cred(), dst)) {
+ ret = -EPERM;
+ goto exit;
+ } else if (kmsg->msg.flags & KDBUS_MSG_EXPECT_REPLY) {
+ wait = kdbus_reply_new(dst, src, &kmsg->msg, name, false);
+ if (IS_ERR(wait)) {
+ ret = PTR_ERR(wait);
+ wait = NULL;
+ goto exit;
+ }
+ }
+
+ /* attach metadata */
+
+ attach = kdbus_meta_calc_attach_flags(src, dst);
+
+ if (!src->faked_meta) {
+ ret = kdbus_meta_proc_collect(kmsg->proc_meta, attach);
+ if (ret < 0 && !is_signal)
+ goto exit;
+ }
+
+ ret = kdbus_meta_conn_collect(kmsg->conn_meta, kmsg, src, attach);
+ if (ret < 0 && !is_signal)
+ goto exit;
+
+ /* send message */
+
+ if (!is_signal)
+ kdbus_bus_eavesdrop(bus, src, kmsg);
+
+ ret = kdbus_conn_entry_insert(src, dst, kmsg, wait);
+ if (ret < 0 && !is_signal)
+ goto exit;
+
+ /* signals are treated like broadcasts, recv-errors are ignored */
+ ret = 0;
+
+exit:
+ up_read(&bus->name_registry->rwlock);
+ kdbus_reply_unref(wait);
+ kdbus_conn_unref(dst);
+ return ret;
+}
+
+/**
+ * kdbus_conn_move_messages() - move messages from one connection to another
+ * @conn_dst: Connection to copy to
+ * @conn_src: Connection to copy from
+ * @name_id: Filter for the sequence number of the registered
+ * name, 0 means no filtering.
+ *
+ * Move all messages from one connection to another. This is used when
+ * an implementer connection is taking over/giving back a well-known name
+ * from/to an activator connection.
+ */
+void kdbus_conn_move_messages(struct kdbus_conn *conn_dst,
+ struct kdbus_conn *conn_src,
+ u64 name_id)
+{
+ struct kdbus_queue_entry *e, *e_tmp;
+ struct kdbus_reply *r, *r_tmp;
+ struct kdbus_bus *bus;
+ struct kdbus_conn *c;
+ LIST_HEAD(msg_list);
+ int i, ret = 0;
+
+ if (WARN_ON(conn_src == conn_dst))
+ return;
+
+ bus = conn_src->ep->bus;
+
+ /* lock order: domain -> bus -> ep -> names -> conn */
+ down_read(&bus->conn_rwlock);
+ hash_for_each(bus->conn_hash, i, c, hentry) {
+ if (c == conn_src || c == conn_dst)
+ continue;
+
+ mutex_lock(&c->lock);
+ list_for_each_entry_safe(r, r_tmp, &c->reply_list, entry) {
+ if (r->reply_src != conn_src)
+ continue;
+
+ /* filter messages for a specific name */
+ if (name_id > 0 && r->name_id != name_id)
+ continue;
+
+ kdbus_conn_unref(r->reply_src);
+ r->reply_src = kdbus_conn_ref(conn_dst);
+ }
+ mutex_unlock(&c->lock);
+ }
+ up_read(&bus->conn_rwlock);
+
+ kdbus_conn_lock2(conn_src, conn_dst);
+ list_for_each_entry_safe(e, e_tmp, &conn_src->queue.msg_list, entry) {
+ /* filter messages for a specific name */
+ if (name_id > 0 && e->dst_name_id != name_id)
+ continue;
+
+ if (!(conn_dst->flags & KDBUS_HELLO_ACCEPT_FD) &&
+ e->msg_res && e->msg_res->fds_count > 0) {
+ kdbus_conn_lost_message(conn_dst);
+ kdbus_queue_entry_free(e);
+ continue;
+ }
+
+ ret = kdbus_queue_entry_move(e, conn_dst);
+ if (ret < 0) {
+ kdbus_conn_lost_message(conn_dst);
+ kdbus_queue_entry_free(e);
+ continue;
+ }
+ }
+ kdbus_conn_unlock2(conn_src, conn_dst);
+
+ /* wake up poll() */
+ wake_up_interruptible(&conn_dst->wait);
+}
+
+/* query the policy-database for all names of @whom */
+static bool kdbus_conn_policy_query_all(struct kdbus_conn *conn,
+ const struct cred *conn_creds,
+ struct kdbus_policy_db *db,
+ struct kdbus_conn *whom,
+ unsigned int access)
+{
+ struct kdbus_name_entry *ne;
+ bool pass = false;
+ int res;
+
+ lockdep_assert_held(&conn->ep->bus->name_registry->rwlock);
+
+ down_read(&db->entries_rwlock);
+ mutex_lock(&whom->lock);
+
+ list_for_each_entry(ne, &whom->names_list, conn_entry) {
+ res = kdbus_policy_query_unlocked(db, conn_creds ? : conn->cred,
+ ne->name,
+ kdbus_strhash(ne->name));
+ if (res >= (int)access) {
+ pass = true;
+ break;
+ }
+ }
+
+ mutex_unlock(&whom->lock);
+ up_read(&db->entries_rwlock);
+
+ return pass;
+}
+
+/**
+ * kdbus_conn_policy_own_name() - verify a connection can own the given name
+ * @conn: Connection
+ * @conn_creds: Credentials of @conn to use for policy check
+ * @name: Name
+ *
+ * This verifies that @conn is allowed to acquire the well-known name @name.
+ *
+ * Return: true if allowed, false if not.
+ */
+bool kdbus_conn_policy_own_name(struct kdbus_conn *conn,
+ const struct cred *conn_creds,
+ const char *name)
+{
+ unsigned int hash = kdbus_strhash(name);
+ int res;
+
+ if (!conn_creds)
+ conn_creds = conn->cred;
+
+ if (conn->ep->user) {
+ res = kdbus_policy_query(&conn->ep->policy_db, conn_creds,
+ name, hash);
+ if (res < KDBUS_POLICY_OWN)
+ return false;
+ }
+
+ if (conn->privileged)
+ return true;
+
+ res = kdbus_policy_query(&conn->ep->bus->policy_db, conn_creds,
+ name, hash);
+ return res >= KDBUS_POLICY_OWN;
+}
+
+/**
+ * kdbus_conn_policy_talk() - verify a connection can talk to a given peer
+ * @conn: Connection that tries to talk
+ * @conn_creds: Credentials of @conn to use for policy check
+ * @to: Connection that is talked to
+ *
+ * This verifies that @conn is allowed to talk to @to.
+ *
+ * Return: true if allowed, false if not.
+ */
+bool kdbus_conn_policy_talk(struct kdbus_conn *conn,
+ const struct cred *conn_creds,
+ struct kdbus_conn *to)
+{
+ if (!conn_creds)
+ conn_creds = conn->cred;
+
+ if (conn->ep->user &&
+ !kdbus_conn_policy_query_all(conn, conn_creds, &conn->ep->policy_db,
+ to, KDBUS_POLICY_TALK))
+ return false;
+
+ if (conn->privileged)
+ return true;
+ if (uid_eq(conn_creds->euid, to->cred->uid))
+ return true;
+
+ return kdbus_conn_policy_query_all(conn, conn_creds,
+ &conn->ep->bus->policy_db, to,
+ KDBUS_POLICY_TALK);
+}
+
+/**
+ * kdbus_conn_policy_see_name_unlocked() - verify a connection can see a given
+ * name
+ * @conn: Connection
+ * @conn_creds: Credentials of @conn to use for policy check
+ * @name: Name
+ *
+ * This verifies that @conn is allowed to see the well-known name @name. Caller
+ * must hold policy-lock.
+ *
+ * Return: true if allowed, false if not.
+ */
+bool kdbus_conn_policy_see_name_unlocked(struct kdbus_conn *conn,
+ const struct cred *conn_creds,
+ const char *name)
+{
+ int res;
+
+ /*
+ * By default, all names are visible on a bus. SEE policies can only be
+ * installed on custom endpoints, where by default no name is visible.
+ */
+ if (!conn->ep->user)
+ return true;
+
+ res = kdbus_policy_query_unlocked(&conn->ep->policy_db,
+ conn_creds ? : conn->cred,
+ name, kdbus_strhash(name));
+ return res >= KDBUS_POLICY_SEE;
+}
+
+static bool kdbus_conn_policy_see_name(struct kdbus_conn *conn,
+ const struct cred *conn_creds,
+ const char *name)
+{
+ bool res;
+
+ down_read(&conn->ep->policy_db.entries_rwlock);
+ res = kdbus_conn_policy_see_name_unlocked(conn, conn_creds, name);
+ up_read(&conn->ep->policy_db.entries_rwlock);
+
+ return res;
+}
+
+static bool kdbus_conn_policy_see(struct kdbus_conn *conn,
+ const struct cred *conn_creds,
+ struct kdbus_conn *whom)
+{
+ /*
+ * By default, all names are visible on a bus, so a connection can
+ * always see other connections. SEE policies can only be installed on
+ * custom endpoints, where by default no name is visible and we hide
+ * peers from each other, unless you see at least _one_ name of the
+ * peer.
+ */
+ return !conn->ep->user ||
+ kdbus_conn_policy_query_all(conn, conn_creds,
+ &conn->ep->policy_db, whom,
+ KDBUS_POLICY_SEE);
+}
+
+/**
+ * kdbus_conn_policy_see_notification() - verify a connection is allowed to
+ * receive a given kernel notification
+ * @conn: Connection
+ * @conn_creds: Credentials of @conn to use for policy check
+ * @kmsg: The message carrying the notification
+ *
+ * This checks whether @conn is allowed to see the kernel notification @kmsg.
+ *
+ * Return: true if allowed, false if not.
+ */
+bool kdbus_conn_policy_see_notification(struct kdbus_conn *conn,
+ const struct cred *conn_creds,
+ const struct kdbus_kmsg *kmsg)
+{
+ if (WARN_ON(kmsg->msg.src_id != KDBUS_SRC_ID_KERNEL))
+ return false;
+
+ /*
+ * Depending on the notification type, broadcasted kernel notifications
+ * have to be filtered:
+ *
+ * KDBUS_ITEM_NAME_{ADD,REMOVE,CHANGE}: This notification is forwarded
+ * to a peer if, and only if, that peer can see the name this
+ * notification is for.
+ *
+ * KDBUS_ITEM_ID_{ADD,REMOVE}: As new peers cannot have names, and all
+ * names are dropped before a peer is removed, those notifications
+ * cannot be seen on custom endpoints. Thus, we only pass them
+ * through on default endpoints.
+ */
+
+ switch (kmsg->notify_type) {
+ case KDBUS_ITEM_NAME_ADD:
+ case KDBUS_ITEM_NAME_REMOVE:
+ case KDBUS_ITEM_NAME_CHANGE:
+ return kdbus_conn_policy_see_name(conn, conn_creds,
+ kmsg->notify_name);
+
+ case KDBUS_ITEM_ID_ADD:
+ case KDBUS_ITEM_ID_REMOVE:
+ return !conn->ep->user;
+
+ default:
+ WARN(1, "Invalid type for notification broadcast: %llu\n",
+ (unsigned long long)kmsg->notify_type);
+ return false;
+ }
+}
+
+/**
+ * kdbus_cmd_hello() - handle KDBUS_CMD_HELLO
+ * @ep: Endpoint to operate on
+ * @privileged: Whether the caller is privileged
+ * @argp: Command payload
+ *
+ * Return: Newly created connection on success, ERR_PTR on failure.
+ */
+struct kdbus_conn *kdbus_cmd_hello(struct kdbus_ep *ep, bool privileged,
+ void __user *argp)
+{
+ struct kdbus_cmd_hello *cmd;
+ struct kdbus_conn *c = NULL;
+ const char *item_name;
+ int ret;
+
+ struct kdbus_arg argv[] = {
+ { .type = KDBUS_ITEM_NEGOTIATE },
+ { .type = KDBUS_ITEM_NAME },
+ { .type = KDBUS_ITEM_CREDS },
+ { .type = KDBUS_ITEM_PIDS },
+ { .type = KDBUS_ITEM_SECLABEL },
+ { .type = KDBUS_ITEM_CONN_DESCRIPTION },
+ { .type = KDBUS_ITEM_POLICY_ACCESS, .multiple = true },
+ };
+ struct kdbus_args args = {
+ .allowed_flags = KDBUS_FLAG_NEGOTIATE |
+ KDBUS_HELLO_ACCEPT_FD |
+ KDBUS_HELLO_ACTIVATOR |
+ KDBUS_HELLO_POLICY_HOLDER |
+ KDBUS_HELLO_MONITOR,
+ .argv = argv,
+ .argc = ARRAY_SIZE(argv),
+ };
+
+ ret = kdbus_args_parse(&args, argp, &cmd);
+ if (ret < 0)
+ return ERR_PTR(ret);
+ if (ret > 0)
+ return NULL;
+
+ item_name = argv[1].item ? argv[1].item->str : NULL;
+
+ c = kdbus_conn_new(ep, privileged, cmd, item_name,
+ argv[2].item ? &argv[2].item->creds : NULL,
+ argv[3].item ? &argv[3].item->pids : NULL,
+ argv[4].item ? argv[4].item->str : NULL,
+ argv[5].item ? argv[5].item->str : NULL);
+ if (IS_ERR(c)) {
+ ret = PTR_ERR(c);
+ c = NULL;
+ goto exit;
+ }
+
+ ret = kdbus_conn_connect(c, item_name);
+ if (ret < 0)
+ goto exit;
+
+ if (kdbus_conn_is_activator(c) || kdbus_conn_is_policy_holder(c)) {
+ ret = kdbus_conn_acquire(c);
+ if (ret < 0)
+ goto exit;
+
+ ret = kdbus_policy_set(&c->ep->bus->policy_db, args.items,
+ args.items_size, 1,
+ kdbus_conn_is_policy_holder(c), c);
+ kdbus_conn_release(c);
+ if (ret < 0)
+ goto exit;
+ }
+
+ if (copy_to_user(argp, cmd, sizeof(*cmd)))
+ ret = -EFAULT;
+
+exit:
+ ret = kdbus_args_clear(&args, ret);
+ if (ret < 0) {
+ if (c) {
+ kdbus_conn_disconnect(c, false);
+ kdbus_conn_unref(c);
+ }
+ return ERR_PTR(ret);
+ }
+ return c;
+}
+
+/**
+ * kdbus_cmd_byebye_unlocked() - handle KDBUS_CMD_BYEBYE
+ * @conn: connection to operate on
+ * @argp: command payload
+ *
+ * The caller must not hold any active reference to @conn or this will deadlock.
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int kdbus_cmd_byebye_unlocked(struct kdbus_conn *conn, void __user *argp)
+{
+ struct kdbus_cmd *cmd;
+ int ret;
+
+ struct kdbus_arg argv[] = {
+ { .type = KDBUS_ITEM_NEGOTIATE },
+ };
+ struct kdbus_args args = {
+ .allowed_flags = KDBUS_FLAG_NEGOTIATE,
+ .argv = argv,
+ .argc = ARRAY_SIZE(argv),
+ };
+
+ if (!kdbus_conn_is_ordinary(conn))
+ return -EOPNOTSUPP;
+
+ ret = kdbus_args_parse(&args, argp, &cmd);
+ if (ret != 0)
+ return ret;
+
+ ret = kdbus_conn_disconnect(conn, true);
+ return kdbus_args_clear(&args, ret);
+}
+
+/**
+ * kdbus_cmd_conn_info() - handle KDBUS_CMD_CONN_INFO
+ * @conn: connection to operate on
+ * @argp: command payload
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int kdbus_cmd_conn_info(struct kdbus_conn *conn, void __user *argp)
+{
+ struct kdbus_meta_conn *conn_meta = NULL;
+ struct kdbus_pool_slice *slice = NULL;
+ struct kdbus_name_entry *entry = NULL;
+ struct kdbus_conn *owner_conn = NULL;
+ struct kdbus_info info = {};
+ struct kdbus_cmd_info *cmd;
+ struct kdbus_bus *bus = conn->ep->bus;
+ struct kvec kvec;
+ size_t meta_size;
+ const char *name;
+ u64 attach_flags;
+ int ret;
+
+ struct kdbus_arg argv[] = {
+ { .type = KDBUS_ITEM_NEGOTIATE },
+ { .type = KDBUS_ITEM_NAME },
+ };
+ struct kdbus_args args = {
+ .allowed_flags = KDBUS_FLAG_NEGOTIATE,
+ .argv = argv,
+ .argc = ARRAY_SIZE(argv),
+ };
+
+ ret = kdbus_args_parse(&args, argp, &cmd);
+ if (ret != 0)
+ return ret;
+
+ /* registry must be held throughout lookup *and* collecting data */
+ down_read(&bus->name_registry->rwlock);
+
+ ret = kdbus_sanitize_attach_flags(cmd->attach_flags, &attach_flags);
+ if (ret < 0)
+ goto exit;
+
+ name = argv[1].item ? argv[1].item->str : NULL;
+
+ if (name) {
+ entry = kdbus_name_lookup_unlocked(bus->name_registry, name);
+ if (!entry || !entry->conn ||
+ !kdbus_conn_policy_see_name(conn, current_cred(), name) ||
+ (cmd->id != 0 && entry->conn->id != cmd->id)) {
+ /* pretend a name doesn't exist if you cannot see it */
+ ret = -ESRCH;
+ goto exit;
+ }
+
+ owner_conn = kdbus_conn_ref(entry->conn);
+ } else if (cmd->id > 0) {
+ owner_conn = kdbus_bus_find_conn_by_id(bus, cmd->id);
+ if (!owner_conn || !kdbus_conn_policy_see(conn, current_cred(),
+ owner_conn)) {
+ /* pretend an id doesn't exist if you cannot see it */
+ ret = -ENXIO;
+ goto exit;
+ }
+ } else {
+ ret = -EINVAL;
+ goto exit;
+ }
+
+ info.id = owner_conn->id;
+ info.flags = owner_conn->flags;
+ kdbus_kvec_set(&kvec, &info, sizeof(info), &info.size);
+
+ attach_flags &= atomic64_read(&owner_conn->attach_flags_send);
+
+ conn_meta = kdbus_meta_conn_new();
+ if (IS_ERR(conn_meta)) {
+ ret = PTR_ERR(conn_meta);
+ conn_meta = NULL;
+ goto exit;
+ }
+
+ ret = kdbus_meta_conn_collect(conn_meta, NULL, owner_conn,
+ attach_flags);
+ if (ret < 0)
+ goto exit;
+
+ ret = kdbus_meta_export_prepare(owner_conn->meta, conn_meta,
+ &attach_flags, &meta_size);
+ if (ret < 0)
+ goto exit;
+
+ slice = kdbus_pool_slice_alloc(conn->pool,
+ info.size + meta_size, false);
+ if (IS_ERR(slice)) {
+ ret = PTR_ERR(slice);
+ slice = NULL;
+ goto exit;
+ }
+
+ ret = kdbus_meta_export(owner_conn->meta, conn_meta, attach_flags,
+ slice, sizeof(info), &meta_size);
+ if (ret < 0)
+ goto exit;
+
+ info.size += meta_size;
+
+ ret = kdbus_pool_slice_copy_kvec(slice, 0, &kvec, 1, sizeof(info));
+ if (ret < 0)
+ goto exit;
+
+ kdbus_pool_slice_publish(slice, &cmd->offset, &cmd->info_size);
+
+ if (kdbus_member_set_user(&cmd->offset, argp, typeof(*cmd), offset) ||
+ kdbus_member_set_user(&cmd->info_size, argp,
+ typeof(*cmd), info_size)) {
+ ret = -EFAULT;
+ goto exit;
+ }
+
+ ret = 0;
+
+exit:
+ up_read(&bus->name_registry->rwlock);
+ kdbus_pool_slice_release(slice);
+ kdbus_meta_conn_unref(conn_meta);
+ kdbus_conn_unref(owner_conn);
+ return kdbus_args_clear(&args, ret);
+}
+
+/**
+ * kdbus_cmd_update() - handle KDBUS_CMD_UPDATE
+ * @conn: connection to operate on
+ * @argp: command payload
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int kdbus_cmd_update(struct kdbus_conn *conn, void __user *argp)
+{
+ struct kdbus_bus *bus = conn->ep->bus;
+ struct kdbus_item *item_policy;
+ u64 *item_attach_send = NULL;
+ u64 *item_attach_recv = NULL;
+ struct kdbus_cmd *cmd;
+ u64 attach_send;
+ u64 attach_recv;
+ int ret;
+
+ struct kdbus_arg argv[] = {
+ { .type = KDBUS_ITEM_NEGOTIATE },
+ { .type = KDBUS_ITEM_ATTACH_FLAGS_SEND },
+ { .type = KDBUS_ITEM_ATTACH_FLAGS_RECV },
+ { .type = KDBUS_ITEM_NAME, .multiple = true },
+ { .type = KDBUS_ITEM_POLICY_ACCESS, .multiple = true },
+ };
+ struct kdbus_args args = {
+ .allowed_flags = KDBUS_FLAG_NEGOTIATE,
+ .argv = argv,
+ .argc = ARRAY_SIZE(argv),
+ };
+
+ ret = kdbus_args_parse(&args, argp, &cmd);
+ if (ret != 0)
+ return ret;
+
+ item_attach_send = argv[1].item ? &argv[1].item->data64[0] : NULL;
+ item_attach_recv = argv[2].item ? &argv[2].item->data64[0] : NULL;
+ item_policy = argv[3].item ? : argv[4].item;
+
+ if (item_attach_send) {
+ if (!kdbus_conn_is_ordinary(conn) &&
+ !kdbus_conn_is_monitor(conn)) {
+ ret = -EOPNOTSUPP;
+ goto exit;
+ }
+
+ ret = kdbus_sanitize_attach_flags(*item_attach_send,
+ &attach_send);
+ if (ret < 0)
+ goto exit;
+
+ if (bus->attach_flags_req & ~attach_send) {
+ ret = -EINVAL;
+ goto exit;
+ }
+ }
+
+ if (item_attach_recv) {
+ if (!kdbus_conn_is_ordinary(conn) &&
+ !kdbus_conn_is_monitor(conn) &&
+ !kdbus_conn_is_activator(conn)) {
+ ret = -EOPNOTSUPP;
+ goto exit;
+ }
+
+ ret = kdbus_sanitize_attach_flags(*item_attach_recv,
+ &attach_recv);
+ if (ret < 0)
+ goto exit;
+ }
+
+ if (item_policy && !kdbus_conn_is_policy_holder(conn)) {
+ ret = -EOPNOTSUPP;
+ goto exit;
+ }
+
+ /* now that we verified the input, update the connection */
+
+ if (item_policy) {
+ ret = kdbus_policy_set(&conn->ep->bus->policy_db, cmd->items,
+ KDBUS_ITEMS_SIZE(cmd, items),
+ 1, true, conn);
+ if (ret < 0)
+ goto exit;
+ }
+
+ if (item_attach_send)
+ atomic64_set(&conn->attach_flags_send, attach_send);
+
+ if (item_attach_recv)
+ atomic64_set(&conn->attach_flags_recv, attach_recv);
+
+exit:
+ return kdbus_args_clear(&args, ret);
+}
+
+/**
+ * kdbus_cmd_send() - handle KDBUS_CMD_SEND
+ * @conn: connection to operate on
+ * @f: file this command was called on
+ * @argp: command payload
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int kdbus_cmd_send(struct kdbus_conn *conn, struct file *f, void __user *argp)
+{
+ struct kdbus_cmd_send *cmd;
+ struct kdbus_kmsg *kmsg = NULL;
+ struct file *cancel_fd = NULL;
+ int ret;
+
+ struct kdbus_arg argv[] = {
+ { .type = KDBUS_ITEM_NEGOTIATE },
+ { .type = KDBUS_ITEM_CANCEL_FD },
+ };
+ struct kdbus_args args = {
+ .allowed_flags = KDBUS_FLAG_NEGOTIATE |
+ KDBUS_SEND_SYNC_REPLY,
+ .argv = argv,
+ .argc = ARRAY_SIZE(argv),
+ };
+
+ if (!kdbus_conn_is_ordinary(conn))
+ return -EOPNOTSUPP;
+
+ ret = kdbus_args_parse(&args, argp, &cmd);
+ if (ret != 0)
+ return ret;
+
+ cmd->reply.return_flags = 0;
+ kdbus_pool_publish_empty(conn->pool, &cmd->reply.offset,
+ &cmd->reply.msg_size);
+
+ if (argv[1].item) {
+ cancel_fd = fget(argv[1].item->fds[0]);
+ if (IS_ERR(cancel_fd)) {
+ ret = PTR_ERR(cancel_fd);
+ cancel_fd = NULL;
+ goto exit;
+ }
+
+ if (!cancel_fd->f_op->poll) {
+ ret = -EINVAL;
+ goto exit;
+ }
+ }
+
+ kmsg = kdbus_kmsg_new_from_cmd(conn, cmd);
+ if (IS_ERR(kmsg)) {
+ ret = PTR_ERR(kmsg);
+ kmsg = NULL;
+ goto exit;
+ }
+
+ if (kmsg->msg.dst_id == KDBUS_DST_ID_BROADCAST) {
+ down_read(&conn->ep->bus->name_registry->rwlock);
+ kdbus_bus_broadcast(conn->ep->bus, conn, kmsg);
+ up_read(&conn->ep->bus->name_registry->rwlock);
+ } else if (cmd->flags & KDBUS_SEND_SYNC_REPLY) {
+ struct kdbus_reply *r;
+ ktime_t exp;
+
+ exp = ns_to_ktime(kmsg->msg.timeout_ns);
+ r = kdbus_conn_call(conn, kmsg, exp);
+ if (IS_ERR(r)) {
+ ret = PTR_ERR(r);
+ goto exit;
+ }
+
+ ret = kdbus_conn_wait_reply(conn, cmd, f, cancel_fd, r, exp);
+ kdbus_reply_unref(r);
+ if (ret < 0)
+ goto exit;
+ } else if ((kmsg->msg.flags & KDBUS_MSG_EXPECT_REPLY) ||
+ kmsg->msg.cookie_reply == 0) {
+ ret = kdbus_conn_unicast(conn, kmsg);
+ if (ret < 0)
+ goto exit;
+ } else {
+ ret = kdbus_conn_reply(conn, kmsg);
+ if (ret < 0)
+ goto exit;
+ }
+
+ if (kdbus_member_set_user(&cmd->reply, argp, typeof(*cmd), reply))
+ ret = -EFAULT;
+
+exit:
+ if (cancel_fd)
+ fput(cancel_fd);
+ kdbus_kmsg_free(kmsg);
+ return kdbus_args_clear(&args, ret);
+}
+
+/**
+ * kdbus_cmd_recv() - handle KDBUS_CMD_RECV
+ * @conn: connection to operate on
+ * @argp: command payload
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int kdbus_cmd_recv(struct kdbus_conn *conn, void __user *argp)
+{
+ struct kdbus_queue_entry *entry;
+ struct kdbus_cmd_recv *cmd;
+ int ret;
+
+ struct kdbus_arg argv[] = {
+ { .type = KDBUS_ITEM_NEGOTIATE },
+ };
+ struct kdbus_args args = {
+ .allowed_flags = KDBUS_FLAG_NEGOTIATE |
+ KDBUS_RECV_PEEK |
+ KDBUS_RECV_DROP |
+ KDBUS_RECV_USE_PRIORITY,
+ .argv = argv,
+ .argc = ARRAY_SIZE(argv),
+ };
+
+ if (!kdbus_conn_is_ordinary(conn) &&
+ !kdbus_conn_is_monitor(conn) &&
+ !kdbus_conn_is_activator(conn))
+ return -EOPNOTSUPP;
+
+ ret = kdbus_args_parse(&args, argp, &cmd);
+ if (ret != 0)
+ return ret;
+
+ cmd->dropped_msgs = 0;
+ cmd->msg.return_flags = 0;
+ kdbus_pool_publish_empty(conn->pool, &cmd->msg.offset,
+ &cmd->msg.msg_size);
+
+ /* DROP+priority is not realiably, so prevent it */
+ if ((cmd->flags & KDBUS_RECV_DROP) &&
+ (cmd->flags & KDBUS_RECV_USE_PRIORITY)) {
+ ret = -EINVAL;
+ goto exit;
+ }
+
+ mutex_lock(&conn->lock);
+
+ entry = kdbus_queue_peek(&conn->queue, cmd->priority,
+ cmd->flags & KDBUS_RECV_USE_PRIORITY);
+ if (!entry) {
+ mutex_unlock(&conn->lock);
+ ret = -EAGAIN;
+ } else if (cmd->flags & KDBUS_RECV_DROP) {
+ struct kdbus_reply *reply = kdbus_reply_ref(entry->reply);
+
+ kdbus_queue_entry_free(entry);
+
+ mutex_unlock(&conn->lock);
+
+ if (reply) {
+ mutex_lock(&reply->reply_dst->lock);
+ if (!list_empty(&reply->entry)) {
+ kdbus_reply_unlink(reply);
+ if (reply->sync)
+ kdbus_sync_reply_wakeup(reply, -EPIPE);
+ else
+ kdbus_notify_reply_dead(conn->ep->bus,
+ reply->reply_dst->id,
+ reply->cookie);
+ }
+ mutex_unlock(&reply->reply_dst->lock);
+ kdbus_notify_flush(conn->ep->bus);
+ }
+
+ kdbus_reply_unref(reply);
+ } else {
+ bool install_fds;
+
+ /*
+ * PEEK just returns the location of the next message. Do not
+ * install FDs nor memfds nor anything else. The only
+ * information of interest should be the message header and
+ * metadata. Any FD numbers in the payload is undefined for
+ * PEEK'ed messages.
+ * Also make sure to never install fds into a connection that
+ * has refused to receive any. Ordinary connections will not get
+ * messages with FDs queued (the receiver will get -ECOMM), but
+ * eavesdroppers might.
+ */
+ install_fds = (conn->flags & KDBUS_HELLO_ACCEPT_FD) &&
+ !(cmd->flags & KDBUS_RECV_PEEK);
+
+ ret = kdbus_queue_entry_install(entry,
+ &cmd->msg.return_flags,
+ install_fds);
+ if (ret < 0) {
+ mutex_unlock(&conn->lock);
+ goto exit;
+ }
+
+ kdbus_pool_slice_publish(entry->slice, &cmd->msg.offset,
+ &cmd->msg.msg_size);
+
+ if (!(cmd->flags & KDBUS_RECV_PEEK))
+ kdbus_queue_entry_free(entry);
+
+ mutex_unlock(&conn->lock);
+ }
+
+ cmd->dropped_msgs = atomic_xchg(&conn->lost_count, 0);
+ if (cmd->dropped_msgs > 0)
+ cmd->return_flags |= KDBUS_RECV_RETURN_DROPPED_MSGS;
+
+ if (kdbus_member_set_user(&cmd->msg, argp, typeof(*cmd), msg) ||
+ kdbus_member_set_user(&cmd->dropped_msgs, argp, typeof(*cmd),
+ dropped_msgs))
+ ret = -EFAULT;
+
+exit:
+ return kdbus_args_clear(&args, ret);
+}
+
+/**
+ * kdbus_cmd_free() - handle KDBUS_CMD_FREE
+ * @conn: connection to operate on
+ * @argp: command payload
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int kdbus_cmd_free(struct kdbus_conn *conn, void __user *argp)
+{
+ struct kdbus_cmd_free *cmd;
+ int ret;
+
+ struct kdbus_arg argv[] = {
+ { .type = KDBUS_ITEM_NEGOTIATE },
+ };
+ struct kdbus_args args = {
+ .allowed_flags = KDBUS_FLAG_NEGOTIATE,
+ .argv = argv,
+ .argc = ARRAY_SIZE(argv),
+ };
+
+ if (!kdbus_conn_is_ordinary(conn) &&
+ !kdbus_conn_is_monitor(conn) &&
+ !kdbus_conn_is_activator(conn))
+ return -EOPNOTSUPP;
+
+ ret = kdbus_args_parse(&args, argp, &cmd);
+ if (ret != 0)
+ return ret;
+
+ ret = kdbus_pool_release_offset(conn->pool, cmd->offset);
+
+ return kdbus_args_clear(&args, ret);
+}
--- /dev/null
+/*
+ * Copyright (C) 2013-2015 Kay Sievers
+ * Copyright (C) 2013-2015 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+ * Copyright (C) 2013-2015 Daniel Mack <daniel@zonque.org>
+ * Copyright (C) 2013-2015 David Herrmann <dh.herrmann@gmail.com>
+ * Copyright (C) 2013-2015 Linux Foundation
+ * Copyright (C) 2014-2015 Djalal Harouni <tixxdz@opendz.org>
+ *
+ * kdbus is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License as published by the
+ * Free Software Foundation; either version 2.1 of the License, or (at
+ * your option) any later version.
+ */
+
+#include <linux/audit.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/hashtable.h>
+#include <linux/idr.h>
+#include <linux/init.h>
+#include <linux/math64.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+#include <linux/uio.h>
+
+#include "util.h"
+#include "domain.h"
+#include "connection.h"
+#include "item.h"
+#include "message.h"
+#include "metadata.h"
+#include "queue.h"
+#include "reply.h"
+
+/**
+ * kdbus_queue_init() - initialize data structure related to a queue
+ * @queue: The queue to initialize
+ */
+void kdbus_queue_init(struct kdbus_queue *queue)
+{
+ INIT_LIST_HEAD(&queue->msg_list);
+ queue->msg_prio_queue = RB_ROOT;
+}
+
+/**
+ * kdbus_queue_peek() - Retrieves an entry from a queue
+ * @queue: The queue
+ * @priority: The minimum priority of the entry to peek
+ * @use_priority: Boolean flag whether or not to peek by priority
+ *
+ * Look for a entry in a queue, either by priority, or the oldest one (FIFO).
+ * The entry is not freed, put off the queue's lists or anything else.
+ *
+ * Return: the peeked queue entry on success, NULL if no suitable msg is found
+ */
+struct kdbus_queue_entry *kdbus_queue_peek(struct kdbus_queue *queue,
+ s64 priority, bool use_priority)
+{
+ struct kdbus_queue_entry *e;
+
+ if (list_empty(&queue->msg_list))
+ return NULL;
+
+ if (use_priority) {
+ /* get next entry with highest priority */
+ e = rb_entry(queue->msg_prio_highest,
+ struct kdbus_queue_entry, prio_node);
+
+ /* no entry with the requested priority */
+ if (e->priority > priority)
+ return NULL;
+ } else {
+ /* ignore the priority, return the next entry in the entry */
+ e = list_first_entry(&queue->msg_list,
+ struct kdbus_queue_entry, entry);
+ }
+
+ return e;
+}
+
+static void kdbus_queue_entry_link(struct kdbus_queue_entry *entry)
+{
+ struct kdbus_queue *queue = &entry->conn->queue;
+ struct rb_node **n, *pn = NULL;
+ bool highest = true;
+
+ lockdep_assert_held(&entry->conn->lock);
+ if (WARN_ON(!list_empty(&entry->entry)))
+ return;
+
+ /* sort into priority entry tree */
+ n = &queue->msg_prio_queue.rb_node;
+ while (*n) {
+ struct kdbus_queue_entry *e;
+
+ pn = *n;
+ e = rb_entry(pn, struct kdbus_queue_entry, prio_node);
+
+ /* existing node for this priority, add to its list */
+ if (likely(entry->priority == e->priority)) {
+ list_add_tail(&entry->prio_entry, &e->prio_entry);
+ goto prio_done;
+ }
+
+ if (entry->priority < e->priority) {
+ n = &pn->rb_left;
+ } else {
+ n = &pn->rb_right;
+ highest = false;
+ }
+ }
+
+ /* cache highest-priority entry */
+ if (highest)
+ queue->msg_prio_highest = &entry->prio_node;
+
+ /* new node for this priority */
+ rb_link_node(&entry->prio_node, pn, n);
+ rb_insert_color(&entry->prio_node, &queue->msg_prio_queue);
+ INIT_LIST_HEAD(&entry->prio_entry);
+
+prio_done:
+ /* add to unsorted fifo list */
+ list_add_tail(&entry->entry, &queue->msg_list);
+}
+
+static void kdbus_queue_entry_unlink(struct kdbus_queue_entry *entry)
+{
+ struct kdbus_queue *queue = &entry->conn->queue;
+
+ lockdep_assert_held(&entry->conn->lock);
+ if (list_empty(&entry->entry))
+ return;
+
+ list_del_init(&entry->entry);
+
+ if (list_empty(&entry->prio_entry)) {
+ /*
+ * Single entry for this priority, update cached
+ * highest-priority entry, remove the tree node.
+ */
+ if (queue->msg_prio_highest == &entry->prio_node)
+ queue->msg_prio_highest = rb_next(&entry->prio_node);
+
+ rb_erase(&entry->prio_node, &queue->msg_prio_queue);
+ } else {
+ struct kdbus_queue_entry *q;
+
+ /*
+ * Multiple entries for this priority entry, get next one in
+ * the list. Update cached highest-priority entry, store the
+ * new one as the tree node.
+ */
+ q = list_first_entry(&entry->prio_entry,
+ struct kdbus_queue_entry, prio_entry);
+ list_del(&entry->prio_entry);
+
+ if (queue->msg_prio_highest == &entry->prio_node)
+ queue->msg_prio_highest = &q->prio_node;
+
+ rb_replace_node(&entry->prio_node, &q->prio_node,
+ &queue->msg_prio_queue);
+ }
+}
+
+/**
+ * kdbus_queue_entry_new() - allocate a queue entry
+ * @conn_dst: destination connection
+ * @kmsg: kmsg object the queue entry should track
+ * @user: user to account message on (or NULL for kernel messages)
+ *
+ * Allocates a queue entry based on a given kmsg and allocate space for
+ * the message payload and the requested metadata in the connection's pool.
+ * The entry is not actually added to the queue's lists at this point.
+ *
+ * Return: the allocated entry on success, or an ERR_PTR on failures.
+ */
+struct kdbus_queue_entry *kdbus_queue_entry_new(struct kdbus_conn *conn_dst,
+ const struct kdbus_kmsg *kmsg,
+ struct kdbus_user *user)
+{
+ struct kdbus_msg_resources *res = kmsg->res;
+ const struct kdbus_msg *msg = &kmsg->msg;
+ struct kdbus_queue_entry *entry;
+ size_t memfd_cnt = 0;
+ struct kvec kvec[2];
+ size_t meta_size;
+ size_t msg_size;
+ u64 payload_off;
+ u64 size = 0;
+ int ret = 0;
+
+ entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+ if (!entry)
+ return ERR_PTR(-ENOMEM);
+
+ INIT_LIST_HEAD(&entry->entry);
+ entry->priority = msg->priority;
+ entry->dst_name_id = kmsg->dst_name_id;
+ entry->msg_res = kdbus_msg_resources_ref(res);
+ entry->proc_meta = kdbus_meta_proc_ref(kmsg->proc_meta);
+ entry->conn_meta = kdbus_meta_conn_ref(kmsg->conn_meta);
+ entry->conn = kdbus_conn_ref(conn_dst);
+
+ if (kmsg->msg.src_id == KDBUS_SRC_ID_KERNEL)
+ msg_size = msg->size;
+ else
+ msg_size = offsetof(struct kdbus_msg, items);
+
+ /* sum up the size of the needed slice */
+ size = msg_size;
+
+ if (res) {
+ size += res->vec_count *
+ KDBUS_ITEM_SIZE(sizeof(struct kdbus_vec));
+
+ if (res->memfd_count) {
+ entry->memfd_offset =
+ kcalloc(res->memfd_count, sizeof(size_t),
+ GFP_KERNEL);
+ if (!entry->memfd_offset) {
+ ret = -ENOMEM;
+ goto exit_free_entry;
+ }
+
+ size += res->memfd_count *
+ KDBUS_ITEM_SIZE(sizeof(struct kdbus_memfd));
+ }
+
+ if (res->fds_count)
+ size += KDBUS_ITEM_SIZE(sizeof(int) * res->fds_count);
+
+ if (res->dst_name)
+ size += KDBUS_ITEM_SIZE(strlen(res->dst_name) + 1);
+ }
+
+ /*
+ * Remember the offset of the metadata part, so we can override
+ * this part later during kdbus_queue_entry_install().
+ */
+ entry->meta_offset = size;
+
+ if (entry->proc_meta || entry->conn_meta) {
+ entry->attach_flags =
+ atomic64_read(&conn_dst->attach_flags_recv);
+
+ ret = kdbus_meta_export_prepare(entry->proc_meta,
+ entry->conn_meta,
+ &entry->attach_flags,
+ &meta_size);
+ if (ret < 0)
+ goto exit_free_entry;
+
+ size += meta_size;
+ }
+
+ payload_off = size;
+ size += kmsg->pool_size;
+ size = KDBUS_ALIGN8(size);
+
+ ret = kdbus_conn_quota_inc(conn_dst, user, size,
+ res ? res->fds_count : 0);
+ if (ret < 0)
+ goto exit_free_entry;
+
+ entry->slice = kdbus_pool_slice_alloc(conn_dst->pool, size, true);
+ if (IS_ERR(entry->slice)) {
+ ret = PTR_ERR(entry->slice);
+ entry->slice = NULL;
+ kdbus_conn_quota_dec(conn_dst, user, size,
+ res ? res->fds_count : 0);
+ goto exit_free_entry;
+ }
+
+ /* we accounted for exactly 'size' bytes, make sure it didn't grow */
+ WARN_ON(kdbus_pool_slice_size(entry->slice) != size);
+ entry->user = kdbus_user_ref(user);
+
+ /* copy message header */
+ kvec[0].iov_base = (char *)msg;
+ kvec[0].iov_len = msg_size;
+
+ ret = kdbus_pool_slice_copy_kvec(entry->slice, 0, kvec, 1, msg_size);
+ if (ret < 0)
+ goto exit_free_entry;
+
+ /* 'size' will now track the write position */
+ size = msg_size;
+
+ /* create message payload items */
+ if (res) {
+ size_t dst_name_len = 0;
+ unsigned int i;
+ size_t sz = 0;
+
+ if (res->dst_name) {
+ dst_name_len = strlen(res->dst_name) + 1;
+ sz += KDBUS_ITEM_SIZE(dst_name_len);
+ }
+
+ for (i = 0; i < res->data_count; ++i) {
+ struct kdbus_vec v;
+ struct kdbus_memfd m;
+
+ switch (res->data[i].type) {
+ case KDBUS_MSG_DATA_VEC:
+ sz += KDBUS_ITEM_SIZE(sizeof(v));
+ break;
+
+ case KDBUS_MSG_DATA_MEMFD:
+ sz += KDBUS_ITEM_SIZE(sizeof(m));
+ break;
+ }
+ }
+
+ if (sz) {
+ struct kdbus_item *items, *item;
+
+ items = kmalloc(sz, GFP_KERNEL);
+ if (!items) {
+ ret = -ENOMEM;
+ goto exit_free_entry;
+ }
+
+ item = items;
+
+ if (res->dst_name)
+ item = kdbus_item_set(item, KDBUS_ITEM_DST_NAME,
+ res->dst_name,
+ dst_name_len);
+
+ for (i = 0; i < res->data_count; ++i) {
+ struct kdbus_msg_data *d = res->data + i;
+ struct kdbus_memfd m = {};
+ struct kdbus_vec v = {};
+
+ switch (d->type) {
+ case KDBUS_MSG_DATA_VEC:
+ v.size = d->size;
+ v.offset = d->vec.off;
+ if (v.offset != ~0ULL)
+ v.offset += payload_off;
+
+ item = kdbus_item_set(item,
+ KDBUS_ITEM_PAYLOAD_OFF,
+ &v, sizeof(v));
+ break;
+
+ case KDBUS_MSG_DATA_MEMFD:
+ /*
+ * Remember the location of memfds, so
+ * we can override the content from
+ * kdbus_queue_entry_install().
+ */
+ entry->memfd_offset[memfd_cnt++] =
+ msg_size +
+ (char *)item - (char *)items +
+ offsetof(struct kdbus_item,
+ memfd);
+
+ item = kdbus_item_set(item,
+ KDBUS_ITEM_PAYLOAD_MEMFD,
+ &m, sizeof(m));
+ break;
+ }
+ }
+
+ kvec[0].iov_base = items;
+ kvec[0].iov_len = sz;
+
+ ret = kdbus_pool_slice_copy_kvec(entry->slice, size,
+ kvec, 1, sz);
+ kfree(items);
+
+ if (ret < 0)
+ goto exit_free_entry;
+
+ size += sz;
+ }
+
+ /*
+ * Remember the location of the FD part, so we can override the
+ * content in kdbus_queue_entry_install().
+ */
+ if (res->fds_count) {
+ entry->fds_offset = size;
+ size += KDBUS_ITEM_SIZE(sizeof(int) * res->fds_count);
+ }
+ }
+
+ /* finally, copy over the actual message payload */
+ if (kmsg->iov_count) {
+ ret = kdbus_pool_slice_copy_iovec(entry->slice, payload_off,
+ kmsg->iov,
+ kmsg->iov_count,
+ kmsg->pool_size);
+ if (ret < 0)
+ goto exit_free_entry;
+ }
+
+ return entry;
+
+exit_free_entry:
+ kdbus_queue_entry_free(entry);
+ return ERR_PTR(ret);
+}
+
+/**
+ * kdbus_queue_entry_free() - free resources of an entry
+ * @entry: The entry to free
+ *
+ * Removes resources allocated by a queue entry, along with the entry itself.
+ * Note that the entry's slice is not freed at this point.
+ */
+void kdbus_queue_entry_free(struct kdbus_queue_entry *entry)
+{
+ if (!entry)
+ return;
+
+ lockdep_assert_held(&entry->conn->lock);
+
+ kdbus_queue_entry_unlink(entry);
+ kdbus_reply_unref(entry->reply);
+
+ if (entry->slice) {
+ kdbus_conn_quota_dec(entry->conn, entry->user,
+ kdbus_pool_slice_size(entry->slice),
+ entry->msg_res ?
+ entry->msg_res->fds_count : 0);
+ kdbus_pool_slice_release(entry->slice);
+ kdbus_user_unref(entry->user);
+ }
+
+ kdbus_msg_resources_unref(entry->msg_res);
+ kdbus_meta_conn_unref(entry->conn_meta);
+ kdbus_meta_proc_unref(entry->proc_meta);
+ kdbus_conn_unref(entry->conn);
+ kfree(entry->memfd_offset);
+ kfree(entry);
+}
+
+/**
+ * kdbus_queue_entry_install() - install message components into the
+ * receiver's process
+ * @entry: The queue entry to install
+ * @return_flags: Pointer to store the return flags for userspace
+ * @install_fds: Whether or not to install associated file descriptors
+ *
+ * This function will create a slice to transport the message header, the
+ * metadata items and other items for information stored in @entry, and
+ * store it as entry->slice.
+ *
+ * If @install_fds is %true, file descriptors will as well be installed.
+ * This function must always be called from the task context of the receiver.
+ *
+ * Return: 0 on success.
+ */
+int kdbus_queue_entry_install(struct kdbus_queue_entry *entry,
+ u64 *return_flags, bool install_fds)
+{
+ u64 msg_size = entry->meta_offset;
+ struct kdbus_conn *conn_dst = entry->conn;
+ struct kdbus_msg_resources *res;
+ bool incomplete_fds = false;
+ struct kvec kvec[2];
+ size_t memfds = 0;
+ int i, ret;
+
+ lockdep_assert_held(&conn_dst->lock);
+
+ if (entry->proc_meta || entry->conn_meta) {
+ size_t meta_size;
+
+ ret = kdbus_meta_export(entry->proc_meta,
+ entry->conn_meta,
+ entry->attach_flags,
+ entry->slice,
+ entry->meta_offset,
+ &meta_size);
+ if (ret < 0)
+ return ret;
+
+ msg_size += meta_size;
+ }
+
+ /* Update message size at offset 0 */
+ kvec[0].iov_base = &msg_size;
+ kvec[0].iov_len = sizeof(msg_size);
+
+ ret = kdbus_pool_slice_copy_kvec(entry->slice, 0, kvec, 1,
+ sizeof(msg_size));
+ if (ret < 0)
+ return ret;
+
+ res = entry->msg_res;
+
+ if (!res)
+ return 0;
+
+ if (res->fds_count) {
+ struct kdbus_item_header hdr;
+ size_t off;
+ int *fds;
+
+ fds = kmalloc_array(res->fds_count, sizeof(int), GFP_KERNEL);
+ if (!fds)
+ return -ENOMEM;
+
+ for (i = 0; i < res->fds_count; i++) {
+ if (install_fds) {
+ fds[i] = get_unused_fd_flags(O_CLOEXEC);
+ if (fds[i] >= 0)
+ fd_install(fds[i],
+ get_file(res->fds[i]));
+ else
+ incomplete_fds = true;
+ } else {
+ fds[i] = -1;
+ }
+ }
+
+ off = entry->fds_offset;
+
+ hdr.type = KDBUS_ITEM_FDS;
+ hdr.size = KDBUS_ITEM_HEADER_SIZE +
+ sizeof(int) * res->fds_count;
+
+ kvec[0].iov_base = &hdr;
+ kvec[0].iov_len = sizeof(hdr);
+
+ kvec[1].iov_base = fds;
+ kvec[1].iov_len = sizeof(int) * res->fds_count;
+
+ ret = kdbus_pool_slice_copy_kvec(entry->slice, off,
+ kvec, 2, hdr.size);
+ kfree(fds);
+
+ if (ret < 0)
+ return ret;
+ }
+
+ for (i = 0; i < res->data_count; ++i) {
+ struct kdbus_msg_data *d = res->data + i;
+ struct kdbus_memfd m;
+
+ if (d->type != KDBUS_MSG_DATA_MEMFD)
+ continue;
+
+ m.start = d->memfd.start;
+ m.size = d->size;
+ m.fd = -1;
+
+ if (install_fds) {
+ m.fd = get_unused_fd_flags(O_CLOEXEC);
+ if (m.fd < 0) {
+ m.fd = -1;
+ incomplete_fds = true;
+ } else {
+ fd_install(m.fd,
+ get_file(d->memfd.file));
+ }
+ }
+
+ kvec[0].iov_base = &m;
+ kvec[0].iov_len = sizeof(m);
+
+ ret = kdbus_pool_slice_copy_kvec(entry->slice,
+ entry->memfd_offset[memfds++],
+ kvec, 1, sizeof(m));
+ if (ret < 0)
+ return ret;
+ }
+
+ if (incomplete_fds)
+ *return_flags |= KDBUS_RECV_RETURN_INCOMPLETE_FDS;
+
+ return 0;
+}
+
+/**
+ * kdbus_queue_entry_enqueue() - enqueue an entry
+ * @entry: entry to enqueue
+ * @reply: reply to link to this entry (or NULL if none)
+ *
+ * This enqueues an unqueued entry into the message queue of the linked
+ * connection. It also binds a reply object to the entry so we can remember it
+ * when the message is moved.
+ *
+ * Once this call returns (and the connection lock is released), this entry can
+ * be dequeued by the target connection. Note that the entry will not be removed
+ * from the queue until it is destroyed.
+ */
+void kdbus_queue_entry_enqueue(struct kdbus_queue_entry *entry,
+ struct kdbus_reply *reply)
+{
+ lockdep_assert_held(&entry->conn->lock);
+
+ if (WARN_ON(entry->reply) || WARN_ON(!list_empty(&entry->entry)))
+ return;
+
+ entry->reply = kdbus_reply_ref(reply);
+ kdbus_queue_entry_link(entry);
+}
+
+/**
+ * kdbus_queue_entry_move() - move queue entry
+ * @e: queue entry to move
+ * @dst: destination connection to queue the entry on
+ *
+ * This moves a queue entry onto a different connection. It allocates a new
+ * slice on the target connection and copies the message over. If the copy
+ * succeeded, we move the entry from @src to @dst.
+ *
+ * On failure, the entry is left untouched.
+ *
+ * The queue entry must be queued right now, and after the call succeeds it will
+ * be queued on the destination, but no longer on the source.
+ *
+ * The caller must hold the connection lock of the source *and* destination.
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int kdbus_queue_entry_move(struct kdbus_queue_entry *e,
+ struct kdbus_conn *dst)
+{
+ struct kdbus_pool_slice *slice = NULL;
+ struct kdbus_conn *src = e->conn;
+ size_t size, fds;
+ int ret;
+
+ lockdep_assert_held(&src->lock);
+ lockdep_assert_held(&dst->lock);
+
+ if (WARN_ON(IS_ERR(e->user)) || WARN_ON(list_empty(&e->entry)))
+ return -EINVAL;
+ if (src == dst)
+ return 0;
+
+ size = kdbus_pool_slice_size(e->slice);
+ fds = e->msg_res ? e->msg_res->fds_count : 0;
+
+ ret = kdbus_conn_quota_inc(dst, e->user, size, fds);
+ if (ret < 0)
+ return ret;
+
+ slice = kdbus_pool_slice_alloc(dst->pool, size, true);
+ if (IS_ERR(slice)) {
+ ret = PTR_ERR(slice);
+ slice = NULL;
+ goto error;
+ }
+
+ ret = kdbus_pool_slice_copy(slice, e->slice);
+ if (ret < 0)
+ goto error;
+
+ kdbus_queue_entry_unlink(e);
+ kdbus_conn_quota_dec(src, e->user, size, fds);
+ kdbus_pool_slice_release(e->slice);
+ kdbus_conn_unref(e->conn);
+
+ e->slice = slice;
+ e->conn = kdbus_conn_ref(dst);
+ kdbus_queue_entry_link(e);
+
+ return 0;
+
+error:
+ kdbus_pool_slice_release(slice);
+ kdbus_conn_quota_dec(dst, e->user, size, fds);
+ return ret;
+}
projects / platform / kernel / linux-3.10.git / commitdiff