cregit-Linux how code gets into the kernel

Release 4.18 fs/ecryptfs/messaging.c

Directory: fs/ecryptfs
 * eCryptfs: Linux filesystem encryption layer
 * Copyright (C) 2004-2008 International Business Machines Corp.
 *   Author(s): Michael A. Halcrow <>
 *              Tyler Hicks <>
 * 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
 * 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_current_euid_hash(uid) \
	hash_long((unsigned long)from_kuid(&init_user_ns, current_euid()), 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; }


Michael Halcrow114100.00%2100.00%

/** * 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; }


Michael Halcrow35100.00%1100.00%

/** * 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); kfree(msg_ctx->msg); msg_ctx->msg = NULL; msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_FREE; }


Michael Halcrow42100.00%2100.00%

/** * ecryptfs_find_daemon_by_euid * @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 current effective 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) { int rc; hlist_for_each_entry(*daemon, &ecryptfs_daemon_hash[ecryptfs_current_euid_hash()], euid_chain) { if (uid_eq((*daemon)->file->f_cred->euid, current_euid())) { rc = 0; goto out; } } rc = -EINVAL; out: return rc; }


Michael Halcrow5182.26%250.00%
Tyler Hicks711.29%125.00%
Eric W. Biedermann46.45%125.00%

/** * ecryptfs_spawn_daemon - Create and initialize a new daemon struct * @daemon: Pointer to set to newly allocated daemon struct * @file: File used when opening /dev/ecryptfs * * 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, struct file *file) { int rc = 0; (*daemon) = kzalloc(sizeof(**daemon), GFP_KERNEL); if (!(*daemon)) { rc = -ENOMEM; goto out; } (*daemon)->file = file; 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_current_euid_hash()]); out: return rc; }


Michael Halcrow12495.38%375.00%
Tyler Hicks64.62%125.00%

/** * 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; 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); mutex_unlock(&daemon->mux); kzfree(daemon); out: return rc; }


Michael Halcrow13199.24%266.67%
Johannes Weiner10.76%133.33%

/** * ecryptfs_process_reponse * @msg: The ecryptfs message received; the caller should sanity check * msg->data_len and free the memory * @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_daemon *daemon, struct ecryptfs_message *msg, u32 seq) { struct ecryptfs_msg_ctx *msg_ctx; size_t msg_size; 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); 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 = kmemdup(msg, msg_size, GFP_KERNEL); if (!msg_ctx->msg) { rc = -ENOMEM; goto unlock; } msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_DONE; wake_up_process(msg_ctx->task); rc = 0; unlock: mutex_unlock(&msg_ctx->mux); out: return rc; }


Michael Halcrow21195.05%360.00%
Tyler Hicks83.60%120.00%
Thomas Meyer31.35%120.00%

/** * 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; int rc; rc = ecryptfs_find_daemon_by_euid(&daemon); if (rc) { rc = -ENOTCONN; 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; }


Michael Halcrow150100.00%2100.00%

/** * 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; }


Michael Halcrow49100.00%1100.00%

/** * 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; }


Michael Halcrow128100.00%1100.00%

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; mutex_unlock(&ecryptfs_daemon_hash_mux); goto out; } for (i = 0; i < (1 << ecryptfs_hash_bits); i++) INIT_HLIST_HEAD(&ecryptfs_daemon_hash[i]); mutex_unlock(&ecryptfs_daemon_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; 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); INIT_LIST_HEAD(&ecryptfs_msg_ctx_arr[i].daemon_out_list); 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); rc = ecryptfs_init_ecryptfs_miscdev(); if (rc) ecryptfs_release_messaging(); out: return rc; }


Michael Halcrow31793.79%342.86%
Andre Osterhues133.85%114.29%
Eric Sandeen51.48%114.29%
Tyler Hicks20.59%114.29%
Jerome Marchand10.30%114.29%

void ecryptfs_release_messaging(void) { 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); 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_hash) { struct ecryptfs_daemon *daemon; struct hlist_node *n; int i; mutex_lock(&ecryptfs_daemon_hash_mux); for (i = 0; i < (1 << ecryptfs_hash_bits); i++) { int rc; hlist_for_each_entry_safe(daemon, n, &ecryptfs_daemon_hash[i], euid_chain) { rc = ecryptfs_exorcise_daemon(daemon); if (rc) printk(KERN_ERR "%s: Error whilst " "attempting to destroy daemon; " "rc = [%d]. Dazed and confused, " "but trying to continue.\n", __func__, rc); } } kfree(ecryptfs_daemon_hash); mutex_unlock(&ecryptfs_daemon_hash_mux); } ecryptfs_destroy_ecryptfs_miscdev(); return; }


Michael Halcrow16492.13%240.00%
Dan Carpenter84.49%120.00%
Andre Osterhues52.81%120.00%
Tyler Hicks10.56%120.00%

Overall Contributors

Michael Halcrow157795.29%531.25%
Tyler Hicks301.81%212.50%
Andre Osterhues191.15%16.25%
Dan Carpenter80.48%16.25%
Eric W. Biedermann50.30%16.25%
Eric Sandeen50.30%16.25%
Thomas Meyer30.18%16.25%
Alexey Dobriyan30.18%16.25%
Tejun Heo30.18%16.25%
Jerome Marchand10.06%16.25%
Johannes Weiner10.06%16.25%
Directory: fs/ecryptfs
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