diff options
Diffstat (limited to 'ipc/kdbus/connection.c')
| -rw-r--r-- | ipc/kdbus/connection.c | 2207 |
1 files changed, 2207 insertions, 0 deletions
diff --git a/ipc/kdbus/connection.c b/ipc/kdbus/connection.c new file mode 100644 index 000000000..d94b417e0 --- /dev/null +++ b/ipc/kdbus/connection.c @@ -0,0 +1,2207 @@ +/* + * 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); + + 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(); + conn->pid = get_pid(task_pid(current)); + get_fs_root(current->fs, &conn->root_path); + 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)); + + /* privileged processes can impersonate somebody else */ + if (creds || pids || seclabel) { + conn->meta_fake = kdbus_meta_fake_new(); + if (IS_ERR(conn->meta_fake)) { + ret = PTR_ERR(conn->meta_fake); + conn->meta_fake = NULL; + goto exit_unref; + } + + ret = kdbus_meta_fake_collect(conn->meta_fake, + creds, pids, seclabel); + if (ret < 0) + goto exit_unref; + } else { + conn->meta_proc = kdbus_meta_proc_new(); + if (IS_ERR(conn->meta_proc)) { + ret = PTR_ERR(conn->meta_proc); + conn->meta_proc = NULL; + goto exit_unref; + } + + ret = kdbus_meta_proc_collect(conn->meta_proc, + 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_fake_free(conn->meta_fake); + kdbus_meta_proc_unref(conn->meta_proc); + kdbus_match_db_free(conn->match_db); + kdbus_pool_free(conn->pool); + kdbus_ep_unref(conn->ep); + path_put(&conn->root_path); + put_pid(conn->pid); + 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(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) + continue; + + if (r->sync) + kdbus_sync_reply_wakeup(r, -EPIPE); + else + /* 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 { + u32 memory; + u16 msgs; + u8 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 allocation + * 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 slices 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 their 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_src, + struct kdbus_conn *conn_dst, + struct kdbus_staging *staging) +{ + /* 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) && + staging->gaps && staging->gaps->n_fds > 0) + return ERR_PTR(-ECOMM); + + return kdbus_queue_entry_new(conn_src, conn_dst, staging); +} + +/* + * 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, + struct kdbus_staging *staging, + struct kdbus_reply *reply_wake) +{ + struct kdbus_queue_entry *entry; + int remote_ret, 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(reply_wake->reply_src, conn_dst, + staging); + 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 + * @staging: Message to send + * @reply: The reply tracker to attach to the queue entry + * @name: Destination name this msg is sent to, or NULL + * + * Return: 0 on success. negative error otherwise. + */ +int kdbus_conn_entry_insert(struct kdbus_conn *conn_src, + struct kdbus_conn *conn_dst, + struct kdbus_staging *staging, + struct kdbus_reply *reply, + const struct kdbus_name_entry *name) +{ + struct kdbus_queue_entry *entry; + int ret; + + kdbus_conn_lock2(conn_src, conn_dst); + + entry = kdbus_conn_entry_make(conn_src, conn_dst, staging); + 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); + } + + /* + * Record the sequence number of the registered name; it will + * be remembered by the queue, in case messages addressed to a + * name need to be moved from or to an activator. + */ + if (name) + entry->dst_name_id = name->name_id; + + 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_staging *staging, + struct kdbus_name_entry **out_name, + struct kdbus_conn **out_dst) +{ + const struct kdbus_msg *msg = staging->msg; + struct kdbus_name_entry *name = NULL; + struct kdbus_conn *dst = NULL; + int ret; + + lockdep_assert_held(&bus->name_registry->rwlock); + + if (!staging->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, + staging->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; + } + } + + *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_staging *staging) +{ + const struct kdbus_msg *msg = staging->msg; + struct kdbus_name_entry *name = NULL; + struct kdbus_reply *reply, *wake = NULL; + struct kdbus_conn *dst = NULL; + struct kdbus_bus *bus = src->ep->bus; + int ret; + + if (WARN_ON(msg->dst_id == KDBUS_DST_ID_BROADCAST) || + WARN_ON(msg->flags & KDBUS_MSG_EXPECT_REPLY) || + WARN_ON(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, staging, &name, &dst); + if (ret < 0) + goto exit; + + mutex_lock(&dst->lock); + reply = kdbus_reply_find(src, dst, 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; + } + + /* send message */ + + kdbus_bus_eavesdrop(bus, src, staging); + + if (wake) + ret = kdbus_conn_entry_sync_attach(dst, staging, wake); + else + ret = kdbus_conn_entry_insert(src, dst, staging, NULL, name); + +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_staging *staging, + ktime_t exp) +{ + const struct kdbus_msg *msg = staging->msg; + struct kdbus_name_entry *name = NULL; + struct kdbus_reply *wait = NULL; + struct kdbus_conn *dst = NULL; + struct kdbus_bus *bus = src->ep->bus; + int ret; + + if (WARN_ON(msg->dst_id == KDBUS_DST_ID_BROADCAST) || + WARN_ON(msg->flags & KDBUS_MSG_SIGNAL) || + WARN_ON(!(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, 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, staging, &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, msg, name, true); + if (IS_ERR(wait)) { + ret = PTR_ERR(wait); + wait = NULL; + goto exit; + } + + /* send message */ + + kdbus_bus_eavesdrop(bus, src, staging); + + ret = kdbus_conn_entry_insert(src, dst, staging, wait, name); + 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_staging *staging) +{ + const struct kdbus_msg *msg = staging->msg; + 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 = (msg->flags & KDBUS_MSG_SIGNAL); + int ret = 0; + + if (WARN_ON(msg->dst_id == KDBUS_DST_ID_BROADCAST) || + WARN_ON(!(msg->flags & KDBUS_MSG_EXPECT_REPLY) && + 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, staging, &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, staging); + + /* drop silently if peer is not interested or not privileged */ + if (!kdbus_match_db_match_msg(dst->match_db, src, staging) || + !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 (msg->flags & KDBUS_MSG_EXPECT_REPLY) { + wait = kdbus_reply_new(dst, src, msg, name, false); + if (IS_ERR(wait)) { + ret = PTR_ERR(wait); + wait = NULL; + goto exit; + } + } + + /* send message */ + + if (!is_signal) + kdbus_bus_eavesdrop(bus, src, staging); + + ret = kdbus_conn_entry_insert(src, dst, staging, wait, name); + 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->gaps && e->gaps->n_fds > 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 + * @msg: Notification message + * + * This checks whether @conn is allowed to see the kernel notification. + * + * 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_msg *msg) +{ + /* + * 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}: Notifications for ID changes are + * broadcast to everyone, to allow tracking peers. + */ + + switch (msg->items[0].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, + msg->items[0].name_change.name); + + case KDBUS_ITEM_ID_ADD: + case KDBUS_ITEM_ID_REMOVE: + return true; + + default: + WARN(1, "Invalid type for notification broadcast: %llu\n", + (unsigned long long)msg->items[0].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: NULL or 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_item *meta_items = NULL; + struct kdbus_info info = {}; + struct kdbus_cmd_info *cmd; + struct kdbus_bus *bus = conn->ep->bus; + struct kvec kvec[3]; + size_t meta_size, cnt = 0; + const char *name; + u64 attach_flags, size = 0; + 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; + } + + 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, owner_conn, 0, attach_flags); + if (ret < 0) + goto exit; + + ret = kdbus_meta_emit(owner_conn->meta_proc, owner_conn->meta_fake, + conn_meta, conn, attach_flags, + &meta_items, &meta_size); + if (ret < 0) + goto exit; + + info.id = owner_conn->id; + info.flags = owner_conn->flags; + + kdbus_kvec_set(&kvec[cnt++], &info, sizeof(info), &size); + if (meta_size > 0) { + kdbus_kvec_set(&kvec[cnt++], meta_items, meta_size, &size); + cnt += !!kdbus_kvec_pad(&kvec[cnt], &size); + } + + info.size = size; + + slice = kdbus_pool_slice_alloc(conn->pool, size, false); + if (IS_ERR(slice)) { + ret = PTR_ERR(slice); + slice = NULL; + goto exit; + } + + ret = kdbus_pool_slice_copy_kvec(slice, 0, kvec, cnt, size); + 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); + kfree(meta_items); + 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_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 (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_staging *staging = NULL; + struct kdbus_msg *msg = NULL; + struct file *cancel_fd = NULL; + int ret, ret2; + + /* command arguments */ + 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), + }; + + /* message arguments */ + struct kdbus_arg msg_argv[] = { + { .type = KDBUS_ITEM_NEGOTIATE }, + { .type = KDBUS_ITEM_PAYLOAD_VEC, .multiple = true }, + { .type = KDBUS_ITEM_PAYLOAD_MEMFD, .multiple = true }, + { .type = KDBUS_ITEM_FDS }, + { .type = KDBUS_ITEM_BLOOM_FILTER }, + { .type = KDBUS_ITEM_DST_NAME }, + }; + struct kdbus_args msg_args = { + .allowed_flags = KDBUS_FLAG_NEGOTIATE | + KDBUS_MSG_EXPECT_REPLY | + KDBUS_MSG_NO_AUTO_START | + KDBUS_MSG_SIGNAL, + .argv = msg_argv, + .argc = ARRAY_SIZE(msg_argv), + }; + + if (!kdbus_conn_is_ordinary(conn)) + return -EOPNOTSUPP; + + /* make sure to parse both, @cmd and @msg on negotiation */ + + ret = kdbus_args_parse(&args, argp, &cmd); + if (ret < 0) + goto exit; + else if (ret > 0 && !cmd->msg_address) /* negotiation without msg */ + goto exit; + + ret2 = kdbus_args_parse_msg(&msg_args, KDBUS_PTR(cmd->msg_address), + &msg); + if (ret2 < 0) { /* cannot parse message */ + ret = ret2; + goto exit; + } else if (ret2 > 0 && !ret) { /* msg-negot implies cmd-negot */ + ret = -EINVAL; + goto exit; + } else if (ret > 0) { /* negotiation */ + goto exit; + } + + /* here we parsed both, @cmd and @msg, and neither wants negotiation */ + + 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 (!cancel_fd) { + ret = -EBADF; + goto exit; + } + + if (!cancel_fd->f_op->poll) { + ret = -EINVAL; + goto exit; + } + } + + /* patch-in the source of this message */ + if (msg->src_id > 0 && msg->src_id != conn->id) { + ret = -EINVAL; + goto exit; + } + msg->src_id = conn->id; + + staging = kdbus_staging_new_user(conn->ep->bus, cmd, msg); + if (IS_ERR(staging)) { + ret = PTR_ERR(staging); + staging = NULL; + goto exit; + } + + if (msg->dst_id == KDBUS_DST_ID_BROADCAST) { + down_read(&conn->ep->bus->name_registry->rwlock); + kdbus_bus_broadcast(conn->ep->bus, conn, staging); + 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(msg->timeout_ns); + r = kdbus_conn_call(conn, staging, 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 ((msg->flags & KDBUS_MSG_EXPECT_REPLY) || + msg->cookie_reply == 0) { + ret = kdbus_conn_unicast(conn, staging); + if (ret < 0) + goto exit; + } else { + ret = kdbus_conn_reply(conn, staging); + 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_staging_free(staging); + ret = kdbus_args_clear(&msg_args, ret); + 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); +} |