/** * eCryptfs: Linux filesystem encryption layer * * Copyright (C) 2004-2008 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 <linux/slab.h>#include <linux/user_namespace.h>#include <linux/nsproxy.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_hash;struct mutex ecryptfs_daemon_hash_mux;static int ecryptfs_hash_bits;#define ecryptfs_uid_hash(uid) \ hash_long((unsigned long)uid, ecryptfs_hash_bits) static u32 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. Sets the msg_ctx task to current. Returns zero on * success; non-zero on error or upon failure to acquire a free * context element. Must be called with ecryptfs_msg_ctx_lists_mux * held. */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)) { printk(KERN_WARNING "%s: 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", __func__, 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 * * Must be called with ecryptfs_msg_ctx_lists_mux held. */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 * * Must be called with ecryptfs_msg_ctx_lists_mux held. */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->msg = NULL; msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_FREE;} /** * ecryptfs_find_daemon_by_euid * @euid: The effective user id which maps to the desired daemon id * @user_ns: The namespace in which @euid applies * @daemon: If return value is zero, points to the desired daemon pointer * * Must be called with ecryptfs_daemon_hash_mux held. * * Search the hash list for the given user id. * * Returns zero if the user id exists in the list; non-zero otherwise. */int ecryptfs_find_daemon_by_euid(struct ecryptfs_daemon **daemon, uid_t euid, struct user_namespace *user_ns){ struct hlist_node *elem; int rc; hlist_for_each_entry(*daemon, elem, &ecryptfs_daemon_hash[ecryptfs_uid_hash(euid)], euid_chain) { if ((*daemon)->euid == euid && (*daemon)->user_ns == user_ns) { rc = 0; goto out; } } rc = -EINVAL;out: return rc;} /** * ecryptfs_spawn_daemon - Create and initialize a new daemon struct * @daemon: Pointer to set to newly allocated daemon struct * @euid: Effective user id for the daemon * @user_ns: The namespace in which @euid applies * @pid: Process id for the daemon * * Must be called ceremoniously while in possession of * ecryptfs_sacred_daemon_hash_mux * * Returns zero on success; non-zero otherwise */intecryptfs_spawn_daemon(struct ecryptfs_daemon **daemon, uid_t euid, struct user_namespace *user_ns, struct pid *pid){ int rc = 0; (*daemon) = kzalloc(sizeof(**daemon), GFP_KERNEL); if (!(*daemon)) { rc = -ENOMEM; printk(KERN_ERR "%s: Failed to allocate [%zd] bytes of " "GFP_KERNEL memory\n", __func__, sizeof(**daemon)); goto out; } (*daemon)->euid = euid; (*daemon)->user_ns = get_user_ns(user_ns); (*daemon)->pid = get_pid(pid); (*daemon)->task = current; mutex_init(&(*daemon)->mux); INIT_LIST_HEAD(&(*daemon)->msg_ctx_out_queue); init_waitqueue_head(&(*daemon)->wait); (*daemon)->num_queued_msg_ctx = 0; hlist_add_head(&(*daemon)->euid_chain, &ecryptfs_daemon_hash[ecryptfs_uid_hash(euid)]);out: return rc;} /** * ecryptfs_exorcise_daemon - Destroy the daemon struct * * Must be called ceremoniously while in possession of * ecryptfs_daemon_hash_mux and the daemon's own mux. */int ecryptfs_exorcise_daemon(struct ecryptfs_daemon *daemon){ struct ecryptfs_msg_ctx *msg_ctx, *msg_ctx_tmp; int rc = 0; mutex_lock(&daemon->mux); if ((daemon->flags & ECRYPTFS_DAEMON_IN_READ) || (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)) { rc = -EBUSY; printk(KERN_WARNING "%s: Attempt to destroy daemon with pid " "[0x%p], but it is in the midst of a read or a poll\n", __func__, daemon->pid); mutex_unlock(&daemon->mux); goto out; } list_for_each_entry_safe(msg_ctx, msg_ctx_tmp, &daemon->msg_ctx_out_queue, daemon_out_list) { list_del(&msg_ctx->daemon_out_list); daemon->num_queued_msg_ctx--; printk(KERN_WARNING "%s: Warning: dropping message that is in " "the out queue of a dying daemon\n", __func__); ecryptfs_msg_ctx_alloc_to_free(msg_ctx); } hlist_del(&daemon->euid_chain); if (daemon->task) wake_up_process(daemon->task); if (daemon->pid) put_pid(daemon->pid); if (daemon->user_ns) put_user_ns(daemon->user_ns); mutex_unlock(&daemon->mux); kzfree(daemon);out: return rc;} /** * ecryptfs_process_quit * @euid: The user ID owner of the message * @user_ns: The namespace in which @euid applies * @pid: The process ID for the userspace program that sent the * message * * Deletes the corresponding daemon for the given euid and pid, if * it is the registered that is requesting the deletion. Returns zero * after deleting the desired daemon; non-zero otherwise. */int ecryptfs_process_quit(uid_t euid, struct user_namespace *user_ns, struct pid *pid){ struct ecryptfs_daemon *daemon; int rc; mutex_lock(&ecryptfs_daemon_hash_mux); rc = ecryptfs_find_daemon_by_euid(&daemon, euid, user_ns); if (rc || !daemon) { rc = -EINVAL; printk(KERN_ERR "Received request from user [%d] to " "unregister unrecognized daemon [0x%p]\n", euid, pid); goto out_unlock; } rc = ecryptfs_exorcise_daemon(daemon);out_unlock: mutex_unlock(&ecryptfs_daemon_hash_mux); return rc;} /** * ecryptfs_process_reponse * @msg: The ecryptfs message received; the caller should sanity check * msg->data_len and free the memory * @pid: The process ID of the userspace application that sent the * message * @seq: The sequence number of the message; must match the sequence * number for the existing message context waiting for this * response * * Processes a response message after sending an operation request to * userspace. Some other process is awaiting this response. Before * sending out its first communications, the other process allocated a * msg_ctx from the ecryptfs_msg_ctx_arr at a particular index. The * response message contains this index so that we can copy over the * response message into the msg_ctx that the process holds a * reference to. The other process is going to wake up, check to see * that msg_ctx->state == ECRYPTFS_MSG_CTX_STATE_DONE, and then * proceed to read off and process the response message. Returns zero * upon delivery to desired context element; non-zero upon delivery * failure or error. * * Returns zero on success; non-zero otherwise */int ecryptfs_process_response(struct ecryptfs_message *msg, uid_t euid, struct user_namespace *user_ns, struct pid *pid, u32 seq){ struct ecryptfs_daemon *uninitialized_var(daemon); struct ecryptfs_msg_ctx *msg_ctx; size_t msg_size; struct nsproxy *nsproxy; struct user_namespace *tsk_user_ns; uid_t ctx_euid; int rc; if (msg->index >= ecryptfs_message_buf_len) { rc = -EINVAL; printk(KERN_ERR "%s: Attempt to reference " "context buffer at index [%d]; maximum " "allowable is [%d]\n", __func__, msg->index, (ecryptfs_message_buf_len - 1)); goto out; } msg_ctx = &ecryptfs_msg_ctx_arr[msg->index]; mutex_lock(&msg_ctx->mux); mutex_lock(&ecryptfs_daemon_hash_mux); rcu_read_lock(); nsproxy = task_nsproxy(msg_ctx->task); if (nsproxy == NULL) { rc = -EBADMSG; printk(KERN_ERR "%s: Receiving process is a zombie. Dropping " "message.\n", __func__); rcu_read_unlock(); mutex_unlock(&ecryptfs_daemon_hash_mux); goto wake_up; } tsk_user_ns = __task_cred(msg_ctx->task)->user_ns; ctx_euid = task_euid(msg_ctx->task); rc = ecryptfs_find_daemon_by_euid(&daemon, ctx_euid, tsk_user_ns); rcu_read_unlock(); mutex_unlock(&ecryptfs_daemon_hash_mux); if (rc) { rc = -EBADMSG; printk(KERN_WARNING "%s: User [%d] received a " "message response from process [0x%p] but does " "not have a registered daemon\n", __func__, ctx_euid, pid); goto wake_up; } if (ctx_euid != euid) { rc = -EBADMSG; printk(KERN_WARNING "%s: Received message from user " "[%d]; expected message from user [%d]\n", __func__, euid, ctx_euid); goto unlock; } if (tsk_user_ns != user_ns) { rc = -EBADMSG; printk(KERN_WARNING "%s: Received message from user_ns " "[0x%p]; expected message from user_ns [0x%p]\n", __func__, user_ns, tsk_user_ns); goto unlock; } if (daemon->pid != pid) { rc = -EBADMSG; printk(KERN_ERR "%s: User [%d] sent a message response " "from an unrecognized process [0x%p]\n", __func__, ctx_euid, pid); goto unlock; } if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_PENDING) { rc = -EINVAL; printk(KERN_WARNING "%s: Desired context element is not " "pending a response\n", __func__); goto unlock; } else if (msg_ctx->counter != seq) { rc = -EINVAL; printk(KERN_WARNING "%s: Invalid message sequence; " "expected [%d]; received [%d]\n", __func__, 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; printk(KERN_ERR "%s: Failed to allocate [%zd] bytes of " "GFP_KERNEL memory\n", __func__, msg_size); 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_locked * @data: The data to send * @data_len: The length of data * @msg_ctx: The message context allocated for the send * * Must be called with ecryptfs_daemon_hash_mux held. * * Returns zero on success; non-zero otherwise */static intecryptfs_send_message_locked(char *data, int data_len, u8 msg_type, struct ecryptfs_msg_ctx **msg_ctx){ struct ecryptfs_daemon *daemon; uid_t euid = current_euid(); int rc; rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns()); if (rc || !daemon) { rc = -ENOTCONN; printk(KERN_ERR "%s: User [%d] does not have a daemon " "registered\n", __func__, euid); goto out; } mutex_lock(&ecryptfs_msg_ctx_lists_mux); rc = ecryptfs_acquire_free_msg_ctx(msg_ctx); if (rc) { mutex_unlock(&ecryptfs_msg_ctx_lists_mux); printk(KERN_WARNING "%s: Could not claim a free " "context element\n", __func__); goto out; } ecryptfs_msg_ctx_free_to_alloc(*msg_ctx); mutex_unlock(&(*msg_ctx)->mux); mutex_unlock(&ecryptfs_msg_ctx_lists_mux); rc = ecryptfs_send_miscdev(data, data_len, *msg_ctx, msg_type, 0, daemon); if (rc) printk(KERN_ERR "%s: Error attempting to send message to " "userspace daemon; rc = [%d]\n", __func__, rc);out: return rc;} /** * ecryptfs_send_message * @data: The data to send * @data_len: The length of data * @msg_ctx: The message context allocated for the send * * Grabs ecryptfs_daemon_hash_mux. * * Returns zero on success; non-zero otherwise */int ecryptfs_send_message(char *data, int data_len, struct ecryptfs_msg_ctx **msg_ctx){ int rc; mutex_lock(&ecryptfs_daemon_hash_mux); rc = ecryptfs_send_message_locked(data, data_len, ECRYPTFS_MSG_REQUEST, msg_ctx); mutex_unlock(&ecryptfs_daemon_hash_mux); 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. Callee must free @msg on success. */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 __init ecryptfs_init_messaging(void){ int i; int rc = 0; if (ecryptfs_number_of_users > ECRYPTFS_MAX_NUM_USERS) { ecryptfs_number_of_users = ECRYPTFS_MAX_NUM_USERS; printk(KERN_WARNING "%s: Specified number of users is " "too large, defaulting to [%d] users\n", __func__, ecryptfs_number_of_users); } mutex_init(&ecryptfs_daemon_hash_mux); mutex_lock(&ecryptfs_daemon_hash_mux); ecryptfs_hash_bits = 1; while (ecryptfs_number_of_users >> ecryptfs_hash_bits) ecryptfs_hash_bits++; ecryptfs_daemon_hash = kmalloc((sizeof(struct hlist_head) * (1 << ecryptfs_hash_bits)), GFP_KERNEL); if (!ecryptfs_daemon_hash) { rc = -ENOMEM; printk(KERN_ERR "%s: Failed to allocate memory\n", __func__); mutex_unlock(&ecryptfs_daemon_hash_mux); goto out; }Lines 1–500 of 578. 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/** * eCryptfs: Linux filesystem encryption layer * * Copyright (C) 2004-2008 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 <linux/slab.h> #include <linux/user_namespace.h> #include <linux/nsproxy.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_hash; struct mutex ecryptfs_daemon_hash_mux; static int ecryptfs_hash_bits; #define ecryptfs_uid_hash(uid) \ hash_long((unsigned long)uid, ecryptfs_hash_bits) static u32 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. Sets the msg_ctx task to current. Returns zero on * success; non-zero on error or upon failure to acquire a free * context element. Must be called with ecryptfs_msg_ctx_lists_mux * held. */ 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)) { printk(KERN_WARNING "%s: 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", __func__, 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 * * Must be called with ecryptfs_msg_ctx_lists_mux held. */ 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 * * Must be called with ecryptfs_msg_ctx_lists_mux held. */ 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->msg = NULL; msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_FREE; } /** * ecryptfs_find_daemon_by_euid * @euid: The effective user id which maps to the desired daemon id * @user_ns: The namespace in which @euid applies * @daemon: If return value is zero, points to the desired daemon pointer * * Must be called with ecryptfs_daemon_hash_mux held. * * Search the hash list for the given user id. * * Returns zero if the user id exists in the list; non-zero otherwise. */ int ecryptfs_find_daemon_by_euid(struct ecryptfs_daemon **daemon, uid_t euid, struct user_namespace *user_ns) { struct hlist_node *elem; int rc; hlist_for_each_entry(*daemon, elem, &ecryptfs_daemon_hash[ecryptfs_uid_hash(euid)], euid_chain) { if ((*daemon)->euid == euid && (*daemon)->user_ns == user_ns) { rc = 0; goto out; } } rc = -EINVAL; out: return rc; } /** * ecryptfs_spawn_daemon - Create and initialize a new daemon struct * @daemon: Pointer to set to newly allocated daemon struct * @euid: Effective user id for the daemon * @user_ns: The namespace in which @euid applies * @pid: Process id for the daemon * * Must be called ceremoniously while in possession of * ecryptfs_sacred_daemon_hash_mux * * Returns zero on success; non-zero otherwise */ int ecryptfs_spawn_daemon(struct ecryptfs_daemon **daemon, uid_t euid, struct user_namespace *user_ns, struct pid *pid) { int rc = 0; (*daemon) = kzalloc(sizeof(**daemon), GFP_KERNEL); if (!(*daemon)) { rc = -ENOMEM; printk(KERN_ERR "%s: Failed to allocate [%zd] bytes of " "GFP_KERNEL memory\n", __func__, sizeof(**daemon)); goto out; } (*daemon)->euid = euid; (*daemon)->user_ns = get_user_ns(user_ns); (*daemon)->pid = get_pid(pid); (*daemon)->task = current; mutex_init(&(*daemon)->mux); INIT_LIST_HEAD(&(*daemon)->msg_ctx_out_queue); init_waitqueue_head(&(*daemon)->wait); (*daemon)->num_queued_msg_ctx = 0; hlist_add_head(&(*daemon)->euid_chain, &ecryptfs_daemon_hash[ecryptfs_uid_hash(euid)]); out: return rc; } /** * ecryptfs_exorcise_daemon - Destroy the daemon struct * * Must be called ceremoniously while in possession of * ecryptfs_daemon_hash_mux and the daemon's own mux. */ int ecryptfs_exorcise_daemon(struct ecryptfs_daemon *daemon) { struct ecryptfs_msg_ctx *msg_ctx, *msg_ctx_tmp; int rc = 0; mutex_lock(&daemon->mux); if ((daemon->flags & ECRYPTFS_DAEMON_IN_READ) || (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)) { rc = -EBUSY; printk(KERN_WARNING "%s: Attempt to destroy daemon with pid " "[0x%p], but it is in the midst of a read or a poll\n", __func__, daemon->pid); mutex_unlock(&daemon->mux); goto out; } list_for_each_entry_safe(msg_ctx, msg_ctx_tmp, &daemon->msg_ctx_out_queue, daemon_out_list) { list_del(&msg_ctx->daemon_out_list); daemon->num_queued_msg_ctx--; printk(KERN_WARNING "%s: Warning: dropping message that is in " "the out queue of a dying daemon\n", __func__); ecryptfs_msg_ctx_alloc_to_free(msg_ctx); } hlist_del(&daemon->euid_chain); if (daemon->task) wake_up_process(daemon->task); if (daemon->pid) put_pid(daemon->pid); if (daemon->user_ns) put_user_ns(daemon->user_ns); mutex_unlock(&daemon->mux); kzfree(daemon); out: return rc; } /** * ecryptfs_process_quit * @euid: The user ID owner of the message * @user_ns: The namespace in which @euid applies * @pid: The process ID for the userspace program that sent the * message * * Deletes the corresponding daemon for the given euid and pid, if * it is the registered that is requesting the deletion. Returns zero * after deleting the desired daemon; non-zero otherwise. */ int ecryptfs_process_quit(uid_t euid, struct user_namespace *user_ns, struct pid *pid) { struct ecryptfs_daemon *daemon; int rc; mutex_lock(&ecryptfs_daemon_hash_mux); rc = ecryptfs_find_daemon_by_euid(&daemon, euid, user_ns); if (rc || !daemon) { rc = -EINVAL; printk(KERN_ERR "Received request from user [%d] to " "unregister unrecognized daemon [0x%p]\n", euid, pid); goto out_unlock; } rc = ecryptfs_exorcise_daemon(daemon); out_unlock: mutex_unlock(&ecryptfs_daemon_hash_mux); return rc; } /** * ecryptfs_process_reponse * @msg: The ecryptfs message received; the caller should sanity check * msg->data_len and free the memory * @pid: The process ID of the userspace application that sent the * message * @seq: The sequence number of the message; must match the sequence * number for the existing message context waiting for this * response * * Processes a response message after sending an operation request to * userspace. Some other process is awaiting this response. Before * sending out its first communications, the other process allocated a * msg_ctx from the ecryptfs_msg_ctx_arr at a particular index. The * response message contains this index so that we can copy over the * response message into the msg_ctx that the process holds a * reference to. The other process is going to wake up, check to see * that msg_ctx->state == ECRYPTFS_MSG_CTX_STATE_DONE, and then * proceed to read off and process the response message. Returns zero * upon delivery to desired context element; non-zero upon delivery * failure or error. * * Returns zero on success; non-zero otherwise */ int ecryptfs_process_response(struct ecryptfs_message *msg, uid_t euid, struct user_namespace *user_ns, struct pid *pid, u32 seq) { struct ecryptfs_daemon *uninitialized_var(daemon); struct ecryptfs_msg_ctx *msg_ctx; size_t msg_size; struct nsproxy *nsproxy; struct user_namespace *tsk_user_ns; uid_t ctx_euid; int rc; if (msg->index >= ecryptfs_message_buf_len) { rc = -EINVAL; printk(KERN_ERR "%s: Attempt to reference " "context buffer at index [%d]; maximum " "allowable is [%d]\n", __func__, msg->index, (ecryptfs_message_buf_len - 1)); goto out; } msg_ctx = &ecryptfs_msg_ctx_arr[msg->index]; mutex_lock(&msg_ctx->mux); mutex_lock(&ecryptfs_daemon_hash_mux); rcu_read_lock(); nsproxy = task_nsproxy(msg_ctx->task); if (nsproxy == NULL) { rc = -EBADMSG; printk(KERN_ERR "%s: Receiving process is a zombie. Dropping " "message.\n", __func__); rcu_read_unlock(); mutex_unlock(&ecryptfs_daemon_hash_mux); goto wake_up; } tsk_user_ns = __task_cred(msg_ctx->task)->user_ns; ctx_euid = task_euid(msg_ctx->task); rc = ecryptfs_find_daemon_by_euid(&daemon, ctx_euid, tsk_user_ns); rcu_read_unlock(); mutex_unlock(&ecryptfs_daemon_hash_mux); if (rc) { rc = -EBADMSG; printk(KERN_WARNING "%s: User [%d] received a " "message response from process [0x%p] but does " "not have a registered daemon\n", __func__, ctx_euid, pid); goto wake_up; } if (ctx_euid != euid) { rc = -EBADMSG; printk(KERN_WARNING "%s: Received message from user " "[%d]; expected message from user [%d]\n", __func__, euid, ctx_euid); goto unlock; } if (tsk_user_ns != user_ns) { rc = -EBADMSG; printk(KERN_WARNING "%s: Received message from user_ns " "[0x%p]; expected message from user_ns [0x%p]\n", __func__, user_ns, tsk_user_ns); goto unlock; } if (daemon->pid != pid) { rc = -EBADMSG; printk(KERN_ERR "%s: User [%d] sent a message response " "from an unrecognized process [0x%p]\n", __func__, ctx_euid, pid); goto unlock; } if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_PENDING) { rc = -EINVAL; printk(KERN_WARNING "%s: Desired context element is not " "pending a response\n", __func__); goto unlock; } else if (msg_ctx->counter != seq) { rc = -EINVAL; printk(KERN_WARNING "%s: Invalid message sequence; " "expected [%d]; received [%d]\n", __func__, 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; printk(KERN_ERR "%s: Failed to allocate [%zd] bytes of " "GFP_KERNEL memory\n", __func__, msg_size); 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_locked * @data: The data to send * @data_len: The length of data * @msg_ctx: The message context allocated for the send * * Must be called with ecryptfs_daemon_hash_mux held. * * Returns zero on success; non-zero otherwise */ static int ecryptfs_send_message_locked(char *data, int data_len, u8 msg_type, struct ecryptfs_msg_ctx **msg_ctx) { struct ecryptfs_daemon *daemon; uid_t euid = current_euid(); int rc; rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns()); if (rc || !daemon) { rc = -ENOTCONN; printk(KERN_ERR "%s: User [%d] does not have a daemon " "registered\n", __func__, euid); goto out; } mutex_lock(&ecryptfs_msg_ctx_lists_mux); rc = ecryptfs_acquire_free_msg_ctx(msg_ctx); if (rc) { mutex_unlock(&ecryptfs_msg_ctx_lists_mux); printk(KERN_WARNING "%s: Could not claim a free " "context element\n", __func__); goto out; } ecryptfs_msg_ctx_free_to_alloc(*msg_ctx); mutex_unlock(&(*msg_ctx)->mux); mutex_unlock(&ecryptfs_msg_ctx_lists_mux); rc = ecryptfs_send_miscdev(data, data_len, *msg_ctx, msg_type, 0, daemon); if (rc) printk(KERN_ERR "%s: Error attempting to send message to " "userspace daemon; rc = [%d]\n", __func__, rc); out: return rc; } /** * ecryptfs_send_message * @data: The data to send * @data_len: The length of data * @msg_ctx: The message context allocated for the send * * Grabs ecryptfs_daemon_hash_mux. * * Returns zero on success; non-zero otherwise */ int ecryptfs_send_message(char *data, int data_len, struct ecryptfs_msg_ctx **msg_ctx) { int rc; mutex_lock(&ecryptfs_daemon_hash_mux); rc = ecryptfs_send_message_locked(data, data_len, ECRYPTFS_MSG_REQUEST, msg_ctx); mutex_unlock(&ecryptfs_daemon_hash_mux); 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. Callee must free @msg on success. */ 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 __init ecryptfs_init_messaging(void) { int i; int rc = 0; if (ecryptfs_number_of_users > ECRYPTFS_MAX_NUM_USERS) { ecryptfs_number_of_users = ECRYPTFS_MAX_NUM_USERS; printk(KERN_WARNING "%s: Specified number of users is " "too large, defaulting to [%d] users\n", __func__, ecryptfs_number_of_users); } mutex_init(&ecryptfs_daemon_hash_mux); mutex_lock(&ecryptfs_daemon_hash_mux); ecryptfs_hash_bits = 1; while (ecryptfs_number_of_users >> ecryptfs_hash_bits) ecryptfs_hash_bits++; ecryptfs_daemon_hash = kmalloc((sizeof(struct hlist_head) * (1 << ecryptfs_hash_bits)), GFP_KERNEL); if (!ecryptfs_daemon_hash) { rc = -ENOMEM; printk(KERN_ERR "%s: Failed to allocate memory\n", __func__); mutex_unlock(&ecryptfs_daemon_hash_mux); goto out; }