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