/** * eCryptfs: Linux filesystem encryption layer * * Copyright (C) 2004-2006 International Business Machines Corp. * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com> * Tyler Hicks <tyhicks@ou.edu> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version * 2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA * 02111-1307, USA. */ #include <linux/sched.h> #include "ecryptfs_kernel.h" static LIST_HEAD(ecryptfs_msg_ctx_free_list); static LIST_HEAD(ecryptfs_msg_ctx_alloc_list); static struct mutex ecryptfs_msg_ctx_lists_mux; static struct hlist_head *ecryptfs_daemon_id_hash; static struct mutex ecryptfs_daemon_id_hash_mux; static int ecryptfs_hash_buckets; #define ecryptfs_uid_hash(uid) \ hash_long((unsigned long)uid, ecryptfs_hash_buckets) static unsigned int ecryptfs_msg_counter; static struct ecryptfs_msg_ctx *ecryptfs_msg_ctx_arr; /** * ecryptfs_acquire_free_msg_ctx * @msg_ctx: The context that was acquired from the free list * * Acquires a context element from the free list and locks the mutex * on the context. Returns zero on success; non-zero on error or upon * failure to acquire a free context element. Be sure to lock the * list mutex before calling. */ static int ecryptfs_acquire_free_msg_ctx(struct ecryptfs_msg_ctx **msg_ctx) { struct list_head *p; int rc; if (list_empty(&ecryptfs_msg_ctx_free_list)) { ecryptfs_printk(KERN_WARNING, "The eCryptfs free " "context list is empty. It may be helpful to " "specify the ecryptfs_message_buf_len " "parameter to be greater than the current " "value of [%d]\n", ecryptfs_message_buf_len); rc = -ENOMEM; goto out; } list_for_each(p, &ecryptfs_msg_ctx_free_list) { *msg_ctx = list_entry(p, struct ecryptfs_msg_ctx, node); if (mutex_trylock(&(*msg_ctx)->mux)) { (*msg_ctx)->task = current; rc = 0; goto out; } } rc = -ENOMEM; out: return rc; } /** * ecryptfs_msg_ctx_free_to_alloc * @msg_ctx: The context to move from the free list to the alloc list * * Be sure to lock the list mutex and the context mutex before * calling. */ static void ecryptfs_msg_ctx_free_to_alloc(struct ecryptfs_msg_ctx *msg_ctx) { list_move(&msg_ctx->node, &ecryptfs_msg_ctx_alloc_list); msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_PENDING; msg_ctx->counter = ++ecryptfs_msg_counter; } /** * ecryptfs_msg_ctx_alloc_to_free * @msg_ctx: The context to move from the alloc list to the free list * * Be sure to lock the list mutex and the context mutex before * calling. */ static void ecryptfs_msg_ctx_alloc_to_free(struct ecryptfs_msg_ctx *msg_ctx) { list_move(&(msg_ctx->node), &ecryptfs_msg_ctx_free_list); if (msg_ctx->msg) kfree(msg_ctx->msg); msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_FREE; } /** * ecryptfs_find_daemon_id * @uid: The user id which maps to the desired daemon id * @id: If return value is zero, points to the desired daemon id * pointer * * Search the hash list for the given user id. Returns zero if the * user id exists in the list; non-zero otherwise. The daemon id hash * mutex should be held before calling this function. */ static int ecryptfs_find_daemon_id(uid_t uid, struct ecryptfs_daemon_id **id) { struct hlist_node *elem; int rc; hlist_for_each_entry(*id, elem, &ecryptfs_daemon_id_hash[ecryptfs_uid_hash(uid)], id_chain) { if ((*id)->uid == uid) { rc = 0; goto out; } } rc = -EINVAL; out: return rc; } static int ecryptfs_send_raw_message(unsigned int transport, u16 msg_type, pid_t pid) { int rc; switch(transport) { case ECRYPTFS_TRANSPORT_NETLINK: rc = ecryptfs_send_netlink(NULL, 0, NULL, msg_type, 0, pid); break; case ECRYPTFS_TRANSPORT_CONNECTOR: case ECRYPTFS_TRANSPORT_RELAYFS: default: rc = -ENOSYS; } return rc; } /** * ecryptfs_process_helo * @transport: The underlying transport (netlink, etc.) * @uid: The user ID owner of the message * @pid: The process ID for the userspace program that sent the * message * * Adds the uid and pid values to the daemon id hash. If a uid * already has a daemon pid registered, the daemon will be * unregistered before the new daemon id is put into the hash list. * Returns zero after adding a new daemon id to the hash list; * non-zero otherwise. */ int ecryptfs_process_helo(unsigned int transport, uid_t uid, pid_t pid) { struct ecryptfs_daemon_id *new_id; struct ecryptfs_daemon_id *old_id; int rc; mutex_lock(&ecryptfs_daemon_id_hash_mux); new_id = kmalloc(sizeof(*new_id), GFP_KERNEL); if (!new_id) { rc = -ENOMEM; ecryptfs_printk(KERN_ERR, "Failed to allocate memory; unable " "to register daemon [%d] for user [%d]\n", pid, uid); goto unlock; } if (!ecryptfs_find_daemon_id(uid, &old_id)) { printk(KERN_WARNING "Received request from user [%d] " "to register daemon [%d]; unregistering daemon " "[%d]\n", uid, pid, old_id->pid); hlist_del(&old_id->id_chain); rc = ecryptfs_send_raw_message(transport, ECRYPTFS_NLMSG_QUIT, old_id->pid); if (rc) printk(KERN_WARNING "Failed to send QUIT " "message to daemon [%d]; rc = [%d]\n", old_id->pid, rc); kfree(old_id); } new_id->uid = uid; new_id->pid = pid; hlist_add_head(&new_id->id_chain, &ecryptfs_daemon_id_hash[ecryptfs_uid_hash(uid)]); rc = 0; unlock: mutex_unlock(&ecryptfs_daemon_id_hash_mux); return rc; } /** * ecryptfs_process_quit * @uid: The user ID owner of the message * @pid: The process ID for the userspace program that sent the * message * * Deletes the corresponding daemon id for the given uid and pid, if * it is the registered that is requesting the deletion. Returns zero * after deleting the desired daemon id; non-zero otherwise. */ int ecryptfs_process_quit(uid_t uid, pid_t pid) { struct ecryptfs_daemon_id *id; int rc; mutex_lock(&ecryptfs_daemon_id_hash_mux); if (ecryptfs_find_daemon_id(uid, &id)) { rc = -EINVAL; ecryptfs_printk(KERN_ERR, "Received request from user [%d] to " "unregister unrecognized daemon [%d]\n", uid, pid); goto unlock; } if (id->pid != pid) { rc = -EINVAL; ecryptfs_printk(KERN_WARNING, "Received request from user [%d] " "with pid [%d] to unregister daemon [%d]\n", uid, pid, id->pid); goto unlock; } hlist_del(&id->id_chain); kfree(id); rc = 0; unlock: mutex_unlock(&ecryptfs_daemon_id_hash_mux); return rc; } /** * ecryptfs_process_reponse * @msg: The ecryptfs message received; the caller should sanity check * msg->data_len * @pid: The process ID of the userspace application that sent the * message * @seq: The sequence number of the message * * Processes a response message after sending a operation request to * userspace. Returns zero upon delivery to desired context element; * non-zero upon delivery failure or error. */ int ecryptfs_process_response(struct ecryptfs_message *msg, uid_t uid, pid_t pid, u32 seq) { struct ecryptfs_daemon_id *id; struct ecryptfs_msg_ctx *msg_ctx; int msg_size; int rc; if (msg->index >= ecryptfs_message_buf_len) { rc = -EINVAL; ecryptfs_printk(KERN_ERR, "Attempt to reference " "context buffer at index [%d]; maximum " "allowable is [%d]\n", msg->index, (ecryptfs_message_buf_len - 1)); goto out; } msg_ctx = &ecryptfs_msg_ctx_arr[msg->index]; mutex_lock(&msg_ctx->mux); if (ecryptfs_find_daemon_id(msg_ctx->task->euid, &id)) { rc = -EBADMSG; ecryptfs_printk(KERN_WARNING, "User [%d] received a " "message response from process [%d] but does " "not have a registered daemon\n", msg_ctx->task->euid, pid); goto wake_up; } if (msg_ctx->task->euid != uid) { rc = -EBADMSG; ecryptfs_printk(KERN_WARNING, "Received message from user " "[%d]; expected message from user [%d]\n", uid, msg_ctx->task->euid); goto unlock; } if (id->pid != pid) { rc = -EBADMSG; ecryptfs_printk(KERN_ERR, "User [%d] received a " "message response from an unrecognized " "process [%d]\n", msg_ctx->task->euid, pid); goto unlock; } if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_PENDING) { rc = -EINVAL; ecryptfs_printk(KERN_WARNING, "Desired context element is not " "pending a response\n"); goto unlock; } else if (msg_ctx->counter != seq) { rc = -EINVAL; ecryptfs_printk(KERN_WARNING, "Invalid message sequence; " "expected [%d]; received [%d]\n", msg_ctx->counter, seq); goto unlock; } msg_size = sizeof(*msg) + msg->data_len; msg_ctx->msg = kmalloc(msg_size, GFP_KERNEL); if (!msg_ctx->msg) { rc = -ENOMEM; ecryptfs_printk(KERN_ERR, "Failed to allocate memory\n"); goto unlock; } memcpy(msg_ctx->msg, msg, msg_size); msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_DONE; rc = 0; wake_up: wake_up_process(msg_ctx->task); unlock: mutex_unlock(&msg_ctx->mux); out: return rc; } /** * ecryptfs_send_message * @transport: The transport over which to send the message (i.e., * netlink) * @data: The data to send * @data_len: The length of data * @msg_ctx: The message context allocated for the send */ int ecryptfs_send_message(unsigned int transport, char *data, int data_len, struct ecryptfs_msg_ctx **msg_ctx) { struct ecryptfs_daemon_id *id; int rc; mutex_lock(&ecryptfs_daemon_id_hash_mux); if (ecryptfs_find_daemon_id(current->euid, &id)) { mutex_unlock(&ecryptfs_daemon_id_hash_mux); rc = -ENOTCONN; ecryptfs_printk(KERN_ERR, "User [%d] does not have a daemon " "registered\n", current->euid); goto out; } mutex_unlock(&ecryptfs_daemon_id_hash_mux); mutex_lock(&ecryptfs_msg_ctx_lists_mux); rc = ecryptfs_acquire_free_msg_ctx(msg_ctx); if (rc) { mutex_unlock(&ecryptfs_msg_ctx_lists_mux); ecryptfs_printk(KERN_WARNING, "Could not claim a free " "context element\n"); goto out; } ecryptfs_msg_ctx_free_to_alloc(*msg_ctx); mutex_unlock(&(*msg_ctx)->mux); mutex_unlock(&ecryptfs_msg_ctx_lists_mux); switch (transport) { case ECRYPTFS_TRANSPORT_NETLINK: rc = ecryptfs_send_netlink(data, data_len, *msg_ctx, ECRYPTFS_NLMSG_REQUEST, 0, id->pid); break; case ECRYPTFS_TRANSPORT_CONNECTOR: case ECRYPTFS_TRANSPORT_RELAYFS: default: rc = -ENOSYS; } if (rc) { printk(KERN_ERR "Error attempting to send message to userspace " "daemon; rc = [%d]\n", rc); } out: return rc; } /** * ecryptfs_wait_for_response * @msg_ctx: The context that was assigned when sending a message * @msg: The incoming message from userspace; not set if rc != 0 * * Sleeps until awaken by ecryptfs_receive_message or until the amount * of time exceeds ecryptfs_message_wait_timeout. If zero is * returned, msg will point to a valid message from userspace; a * non-zero value is returned upon failure to receive a message or an * error occurs. */ int ecryptfs_wait_for_response(struct ecryptfs_msg_ctx *msg_ctx, struct ecryptfs_message **msg) { signed long timeout = ecryptfs_message_wait_timeout * HZ; int rc = 0; sleep: timeout = schedule_timeout_interruptible(timeout); mutex_lock(&ecryptfs_msg_ctx_lists_mux); mutex_lock(&msg_ctx->mux); if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_DONE) { if (timeout) { mutex_unlock(&msg_ctx->mux); mutex_unlock(&ecryptfs_msg_ctx_lists_mux); goto sleep; } rc = -ENOMSG; } else { *msg = msg_ctx->msg; msg_ctx->msg = NULL; } ecryptfs_msg_ctx_alloc_to_free(msg_ctx); mutex_unlock(&msg_ctx->mux); mutex_unlock(&ecryptfs_msg_ctx_lists_mux); return rc; } int ecryptfs_init_messaging(unsigned int transport) { int i; int rc = 0; if (ecryptfs_number_of_users > ECRYPTFS_MAX_NUM_USERS) { ecryptfs_number_of_users = ECRYPTFS_MAX_NUM_USERS; ecryptfs_printk(KERN_WARNING, "Specified number of users is " "too large, defaulting to [%d] users\n", ecryptfs_number_of_users); } mutex_init(&ecryptfs_daemon_id_hash_mux); mutex_lock(&ecryptfs_daemon_id_hash_mux); ecryptfs_hash_buckets = 0; while (ecryptfs_number_of_users >> ++ecryptfs_hash_buckets); ecryptfs_daemon_id_hash = kmalloc(sizeof(struct hlist_head) * ecryptfs_hash_buckets, GFP_KERNEL); if (!ecryptfs_daemon_id_hash) { rc = -ENOMEM; ecryptfs_printk(KERN_ERR, "Failed to allocate memory\n"); goto out; } for (i = 0; i < ecryptfs_hash_buckets; i++) INIT_HLIST_HEAD(&ecryptfs_daemon_id_hash[i]); mutex_unlock(&ecryptfs_daemon_id_hash_mux); ecryptfs_msg_ctx_arr = kmalloc((sizeof(struct ecryptfs_msg_ctx) * ecryptfs_message_buf_len), GFP_KERNEL); if (!ecryptfs_msg_ctx_arr) { rc = -ENOMEM; ecryptfs_printk(KERN_ERR, "Failed to allocate memory\n"); goto out; } mutex_init(&ecryptfs_msg_ctx_lists_mux); mutex_lock(&ecryptfs_msg_ctx_lists_mux); ecryptfs_msg_counter = 0; for (i = 0; i < ecryptfs_message_buf_len; i++) { INIT_LIST_HEAD(&ecryptfs_msg_ctx_arr[i].node); mutex_init(&ecryptfs_msg_ctx_arr[i].mux); mutex_lock(&ecryptfs_msg_ctx_arr[i].mux); ecryptfs_msg_ctx_arr[i].index = i; ecryptfs_msg_ctx_arr[i].state = ECRYPTFS_MSG_CTX_STATE_FREE; ecryptfs_msg_ctx_arr[i].counter = 0; ecryptfs_msg_ctx_arr[i].task = NULL; ecryptfs_msg_ctx_arr[i].msg = NULL; list_add_tail(&ecryptfs_msg_ctx_arr[i].node, &ecryptfs_msg_ctx_free_list); mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux); } mutex_unlock(&ecryptfs_msg_ctx_lists_mux); switch(transport) { case ECRYPTFS_TRANSPORT_NETLINK: rc = ecryptfs_init_netlink(); if (rc) ecryptfs_release_messaging(transport); break; case ECRYPTFS_TRANSPORT_CONNECTOR: case ECRYPTFS_TRANSPORT_RELAYFS: default: rc = -ENOSYS; } out: return rc; } void ecryptfs_release_messaging(unsigned int transport) { if (ecryptfs_msg_ctx_arr) { int i; mutex_lock(&ecryptfs_msg_ctx_lists_mux); for (i = 0; i < ecryptfs_message_buf_len; i++) { mutex_lock(&ecryptfs_msg_ctx_arr[i].mux); if (ecryptfs_msg_ctx_arr[i].msg) kfree(ecryptfs_msg_ctx_arr[i].msg); mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux); } kfree(ecryptfs_msg_ctx_arr); mutex_unlock(&ecryptfs_msg_ctx_lists_mux); } if (ecryptfs_daemon_id_hash) { struct hlist_node *elem; struct ecryptfs_daemon_id *id; int i; mutex_lock(&ecryptfs_daemon_id_hash_mux); for (i = 0; i < ecryptfs_hash_buckets; i++) { hlist_for_each_entry(id, elem, &ecryptfs_daemon_id_hash[i], id_chain) { hlist_del(elem); kfree(id); } } kfree(ecryptfs_daemon_id_hash); mutex_unlock(&ecryptfs_daemon_id_hash_mux); } switch(transport) { case ECRYPTFS_TRANSPORT_NETLINK: ecryptfs_release_netlink(); break; case ECRYPTFS_TRANSPORT_CONNECTOR: case ECRYPTFS_TRANSPORT_RELAYFS: default: break; } return; }