v4.19.13 snapshot.
diff --git a/fs/ecryptfs/miscdev.c b/fs/ecryptfs/miscdev.c
new file mode 100644
index 0000000..2d1158e
--- /dev/null
+++ b/fs/ecryptfs/miscdev.c
@@ -0,0 +1,507 @@
+/**
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 2008 International Business Machines Corp.
+ * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
+ *
+ * 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/fs.h>
+#include <linux/hash.h>
+#include <linux/random.h>
+#include <linux/miscdevice.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/module.h>
+#include "ecryptfs_kernel.h"
+
+static atomic_t ecryptfs_num_miscdev_opens;
+
+/**
+ * ecryptfs_miscdev_poll
+ * @file: dev file
+ * @pt: dev poll table (ignored)
+ *
+ * Returns the poll mask
+ */
+static __poll_t
+ecryptfs_miscdev_poll(struct file *file, poll_table *pt)
+{
+ struct ecryptfs_daemon *daemon = file->private_data;
+ __poll_t mask = 0;
+
+ mutex_lock(&daemon->mux);
+ if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
+ printk(KERN_WARNING "%s: Attempt to poll on zombified "
+ "daemon\n", __func__);
+ goto out_unlock_daemon;
+ }
+ if (daemon->flags & ECRYPTFS_DAEMON_IN_READ)
+ goto out_unlock_daemon;
+ if (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)
+ goto out_unlock_daemon;
+ daemon->flags |= ECRYPTFS_DAEMON_IN_POLL;
+ mutex_unlock(&daemon->mux);
+ poll_wait(file, &daemon->wait, pt);
+ mutex_lock(&daemon->mux);
+ if (!list_empty(&daemon->msg_ctx_out_queue))
+ mask |= EPOLLIN | EPOLLRDNORM;
+out_unlock_daemon:
+ daemon->flags &= ~ECRYPTFS_DAEMON_IN_POLL;
+ mutex_unlock(&daemon->mux);
+ return mask;
+}
+
+/**
+ * ecryptfs_miscdev_open
+ * @inode: inode of miscdev handle (ignored)
+ * @file: file for miscdev handle
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int
+ecryptfs_miscdev_open(struct inode *inode, struct file *file)
+{
+ struct ecryptfs_daemon *daemon = NULL;
+ int rc;
+
+ mutex_lock(&ecryptfs_daemon_hash_mux);
+ rc = ecryptfs_find_daemon_by_euid(&daemon);
+ if (!rc) {
+ rc = -EINVAL;
+ goto out_unlock_daemon_list;
+ }
+ rc = ecryptfs_spawn_daemon(&daemon, file);
+ if (rc) {
+ printk(KERN_ERR "%s: Error attempting to spawn daemon; "
+ "rc = [%d]\n", __func__, rc);
+ goto out_unlock_daemon_list;
+ }
+ mutex_lock(&daemon->mux);
+ if (daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN) {
+ rc = -EBUSY;
+ goto out_unlock_daemon;
+ }
+ daemon->flags |= ECRYPTFS_DAEMON_MISCDEV_OPEN;
+ file->private_data = daemon;
+ atomic_inc(&ecryptfs_num_miscdev_opens);
+out_unlock_daemon:
+ mutex_unlock(&daemon->mux);
+out_unlock_daemon_list:
+ mutex_unlock(&ecryptfs_daemon_hash_mux);
+ return rc;
+}
+
+/**
+ * ecryptfs_miscdev_release
+ * @inode: inode of fs/ecryptfs/euid handle (ignored)
+ * @file: file for fs/ecryptfs/euid handle
+ *
+ * This keeps the daemon registered until the daemon sends another
+ * ioctl to fs/ecryptfs/ctl or until the kernel module unregisters.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int
+ecryptfs_miscdev_release(struct inode *inode, struct file *file)
+{
+ struct ecryptfs_daemon *daemon = file->private_data;
+ int rc;
+
+ mutex_lock(&daemon->mux);
+ BUG_ON(!(daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN));
+ daemon->flags &= ~ECRYPTFS_DAEMON_MISCDEV_OPEN;
+ atomic_dec(&ecryptfs_num_miscdev_opens);
+ mutex_unlock(&daemon->mux);
+
+ mutex_lock(&ecryptfs_daemon_hash_mux);
+ rc = ecryptfs_exorcise_daemon(daemon);
+ mutex_unlock(&ecryptfs_daemon_hash_mux);
+ if (rc) {
+ printk(KERN_CRIT "%s: Fatal error whilst attempting to "
+ "shut down daemon; rc = [%d]. Please report this "
+ "bug.\n", __func__, rc);
+ BUG();
+ }
+ return rc;
+}
+
+/**
+ * ecryptfs_send_miscdev
+ * @data: Data to send to daemon; may be NULL
+ * @data_size: Amount of data to send to daemon
+ * @msg_ctx: Message context, which is used to handle the reply. If
+ * this is NULL, then we do not expect a reply.
+ * @msg_type: Type of message
+ * @msg_flags: Flags for message
+ * @daemon: eCryptfs daemon object
+ *
+ * Add msg_ctx to queue and then, if it exists, notify the blocked
+ * miscdevess about the data being available. Must be called with
+ * ecryptfs_daemon_hash_mux held.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_send_miscdev(char *data, size_t data_size,
+ struct ecryptfs_msg_ctx *msg_ctx, u8 msg_type,
+ u16 msg_flags, struct ecryptfs_daemon *daemon)
+{
+ struct ecryptfs_message *msg;
+
+ msg = kmalloc((sizeof(*msg) + data_size), GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
+
+ mutex_lock(&msg_ctx->mux);
+ msg_ctx->msg = msg;
+ msg_ctx->msg->index = msg_ctx->index;
+ msg_ctx->msg->data_len = data_size;
+ msg_ctx->type = msg_type;
+ memcpy(msg_ctx->msg->data, data, data_size);
+ msg_ctx->msg_size = (sizeof(*msg_ctx->msg) + data_size);
+ list_add_tail(&msg_ctx->daemon_out_list, &daemon->msg_ctx_out_queue);
+ mutex_unlock(&msg_ctx->mux);
+
+ mutex_lock(&daemon->mux);
+ daemon->num_queued_msg_ctx++;
+ wake_up_interruptible(&daemon->wait);
+ mutex_unlock(&daemon->mux);
+
+ return 0;
+}
+
+/*
+ * miscdevfs packet format:
+ * Octet 0: Type
+ * Octets 1-4: network byte order msg_ctx->counter
+ * Octets 5-N0: Size of struct ecryptfs_message to follow
+ * Octets N0-N1: struct ecryptfs_message (including data)
+ *
+ * Octets 5-N1 not written if the packet type does not include a message
+ */
+#define PKT_TYPE_SIZE 1
+#define PKT_CTR_SIZE 4
+#define MIN_NON_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE)
+#define MIN_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE \
+ + ECRYPTFS_MIN_PKT_LEN_SIZE)
+/* 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES comes from tag 65 packet format */
+#define MAX_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE \
+ + ECRYPTFS_MAX_PKT_LEN_SIZE \
+ + sizeof(struct ecryptfs_message) \
+ + 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES)
+#define PKT_TYPE_OFFSET 0
+#define PKT_CTR_OFFSET PKT_TYPE_SIZE
+#define PKT_LEN_OFFSET (PKT_TYPE_SIZE + PKT_CTR_SIZE)
+
+/**
+ * ecryptfs_miscdev_read - format and send message from queue
+ * @file: miscdevfs handle
+ * @buf: User buffer into which to copy the next message on the daemon queue
+ * @count: Amount of space available in @buf
+ * @ppos: Offset in file (ignored)
+ *
+ * Pulls the most recent message from the daemon queue, formats it for
+ * being sent via a miscdevfs handle, and copies it into @buf
+ *
+ * Returns the number of bytes copied into the user buffer
+ */
+static ssize_t
+ecryptfs_miscdev_read(struct file *file, char __user *buf, size_t count,
+ loff_t *ppos)
+{
+ struct ecryptfs_daemon *daemon = file->private_data;
+ struct ecryptfs_msg_ctx *msg_ctx;
+ size_t packet_length_size;
+ char packet_length[ECRYPTFS_MAX_PKT_LEN_SIZE];
+ size_t i;
+ size_t total_length;
+ int rc;
+
+ mutex_lock(&daemon->mux);
+ if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
+ rc = 0;
+ printk(KERN_WARNING "%s: Attempt to read from zombified "
+ "daemon\n", __func__);
+ goto out_unlock_daemon;
+ }
+ if (daemon->flags & ECRYPTFS_DAEMON_IN_READ) {
+ rc = 0;
+ goto out_unlock_daemon;
+ }
+ /* This daemon will not go away so long as this flag is set */
+ daemon->flags |= ECRYPTFS_DAEMON_IN_READ;
+check_list:
+ if (list_empty(&daemon->msg_ctx_out_queue)) {
+ mutex_unlock(&daemon->mux);
+ rc = wait_event_interruptible(
+ daemon->wait, !list_empty(&daemon->msg_ctx_out_queue));
+ mutex_lock(&daemon->mux);
+ if (rc < 0) {
+ rc = 0;
+ goto out_unlock_daemon;
+ }
+ }
+ if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
+ rc = 0;
+ goto out_unlock_daemon;
+ }
+ if (list_empty(&daemon->msg_ctx_out_queue)) {
+ /* Something else jumped in since the
+ * wait_event_interruptable() and removed the
+ * message from the queue; try again */
+ goto check_list;
+ }
+ msg_ctx = list_first_entry(&daemon->msg_ctx_out_queue,
+ struct ecryptfs_msg_ctx, daemon_out_list);
+ BUG_ON(!msg_ctx);
+ mutex_lock(&msg_ctx->mux);
+ if (msg_ctx->msg) {
+ rc = ecryptfs_write_packet_length(packet_length,
+ msg_ctx->msg_size,
+ &packet_length_size);
+ if (rc) {
+ rc = 0;
+ printk(KERN_WARNING "%s: Error writing packet length; "
+ "rc = [%d]\n", __func__, rc);
+ goto out_unlock_msg_ctx;
+ }
+ } else {
+ packet_length_size = 0;
+ msg_ctx->msg_size = 0;
+ }
+ total_length = (PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_length_size
+ + msg_ctx->msg_size);
+ if (count < total_length) {
+ rc = 0;
+ printk(KERN_WARNING "%s: Only given user buffer of "
+ "size [%zd], but we need [%zd] to read the "
+ "pending message\n", __func__, count, total_length);
+ goto out_unlock_msg_ctx;
+ }
+ rc = -EFAULT;
+ if (put_user(msg_ctx->type, buf))
+ goto out_unlock_msg_ctx;
+ if (put_user(cpu_to_be32(msg_ctx->counter),
+ (__be32 __user *)(&buf[PKT_CTR_OFFSET])))
+ goto out_unlock_msg_ctx;
+ i = PKT_TYPE_SIZE + PKT_CTR_SIZE;
+ if (msg_ctx->msg) {
+ if (copy_to_user(&buf[i], packet_length, packet_length_size))
+ goto out_unlock_msg_ctx;
+ i += packet_length_size;
+ if (copy_to_user(&buf[i], msg_ctx->msg, msg_ctx->msg_size))
+ goto out_unlock_msg_ctx;
+ i += msg_ctx->msg_size;
+ }
+ rc = i;
+ list_del(&msg_ctx->daemon_out_list);
+ kfree(msg_ctx->msg);
+ msg_ctx->msg = NULL;
+ /* We do not expect a reply from the userspace daemon for any
+ * message type other than ECRYPTFS_MSG_REQUEST */
+ if (msg_ctx->type != ECRYPTFS_MSG_REQUEST)
+ ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
+out_unlock_msg_ctx:
+ mutex_unlock(&msg_ctx->mux);
+out_unlock_daemon:
+ daemon->flags &= ~ECRYPTFS_DAEMON_IN_READ;
+ mutex_unlock(&daemon->mux);
+ return rc;
+}
+
+/**
+ * ecryptfs_miscdev_response - miscdevess response to message previously sent to daemon
+ * @data: Bytes comprising struct ecryptfs_message
+ * @data_size: sizeof(struct ecryptfs_message) + data len
+ * @seq: Sequence number for miscdev response packet
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_miscdev_response(struct ecryptfs_daemon *daemon, char *data,
+ size_t data_size, u32 seq)
+{
+ struct ecryptfs_message *msg = (struct ecryptfs_message *)data;
+ int rc;
+
+ if ((sizeof(*msg) + msg->data_len) != data_size) {
+ printk(KERN_WARNING "%s: (sizeof(*msg) + msg->data_len) = "
+ "[%zd]; data_size = [%zd]. Invalid packet.\n", __func__,
+ (sizeof(*msg) + msg->data_len), data_size);
+ rc = -EINVAL;
+ goto out;
+ }
+ rc = ecryptfs_process_response(daemon, msg, seq);
+ if (rc)
+ printk(KERN_ERR
+ "Error processing response message; rc = [%d]\n", rc);
+out:
+ return rc;
+}
+
+/**
+ * ecryptfs_miscdev_write - handle write to daemon miscdev handle
+ * @file: File for misc dev handle
+ * @buf: Buffer containing user data
+ * @count: Amount of data in @buf
+ * @ppos: Pointer to offset in file (ignored)
+ *
+ * Returns the number of bytes read from @buf
+ */
+static ssize_t
+ecryptfs_miscdev_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ __be32 counter_nbo;
+ u32 seq;
+ size_t packet_size, packet_size_length;
+ char *data;
+ unsigned char packet_size_peek[ECRYPTFS_MAX_PKT_LEN_SIZE];
+ ssize_t rc;
+
+ if (count == 0) {
+ return 0;
+ } else if (count == MIN_NON_MSG_PKT_SIZE) {
+ /* Likely a harmless MSG_HELO or MSG_QUIT - no packet length */
+ goto memdup;
+ } else if (count < MIN_MSG_PKT_SIZE || count > MAX_MSG_PKT_SIZE) {
+ printk(KERN_WARNING "%s: Acceptable packet size range is "
+ "[%d-%zu], but amount of data written is [%zu].\n",
+ __func__, MIN_MSG_PKT_SIZE, MAX_MSG_PKT_SIZE, count);
+ return -EINVAL;
+ }
+
+ if (copy_from_user(packet_size_peek, &buf[PKT_LEN_OFFSET],
+ sizeof(packet_size_peek))) {
+ printk(KERN_WARNING "%s: Error while inspecting packet size\n",
+ __func__);
+ return -EFAULT;
+ }
+
+ rc = ecryptfs_parse_packet_length(packet_size_peek, &packet_size,
+ &packet_size_length);
+ if (rc) {
+ printk(KERN_WARNING "%s: Error parsing packet length; "
+ "rc = [%zd]\n", __func__, rc);
+ return rc;
+ }
+
+ if ((PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_size_length + packet_size)
+ != count) {
+ printk(KERN_WARNING "%s: Invalid packet size [%zu]\n", __func__,
+ packet_size);
+ return -EINVAL;
+ }
+
+memdup:
+ data = memdup_user(buf, count);
+ if (IS_ERR(data)) {
+ printk(KERN_ERR "%s: memdup_user returned error [%ld]\n",
+ __func__, PTR_ERR(data));
+ return PTR_ERR(data);
+ }
+ switch (data[PKT_TYPE_OFFSET]) {
+ case ECRYPTFS_MSG_RESPONSE:
+ if (count < (MIN_MSG_PKT_SIZE
+ + sizeof(struct ecryptfs_message))) {
+ printk(KERN_WARNING "%s: Minimum acceptable packet "
+ "size is [%zd], but amount of data written is "
+ "only [%zd]. Discarding response packet.\n",
+ __func__,
+ (MIN_MSG_PKT_SIZE
+ + sizeof(struct ecryptfs_message)), count);
+ rc = -EINVAL;
+ goto out_free;
+ }
+ memcpy(&counter_nbo, &data[PKT_CTR_OFFSET], PKT_CTR_SIZE);
+ seq = be32_to_cpu(counter_nbo);
+ rc = ecryptfs_miscdev_response(file->private_data,
+ &data[PKT_LEN_OFFSET + packet_size_length],
+ packet_size, seq);
+ if (rc) {
+ printk(KERN_WARNING "%s: Failed to deliver miscdev "
+ "response to requesting operation; rc = [%zd]\n",
+ __func__, rc);
+ goto out_free;
+ }
+ break;
+ case ECRYPTFS_MSG_HELO:
+ case ECRYPTFS_MSG_QUIT:
+ break;
+ default:
+ ecryptfs_printk(KERN_WARNING, "Dropping miscdev "
+ "message of unrecognized type [%d]\n",
+ data[0]);
+ rc = -EINVAL;
+ goto out_free;
+ }
+ rc = count;
+out_free:
+ kfree(data);
+ return rc;
+}
+
+
+static const struct file_operations ecryptfs_miscdev_fops = {
+ .owner = THIS_MODULE,
+ .open = ecryptfs_miscdev_open,
+ .poll = ecryptfs_miscdev_poll,
+ .read = ecryptfs_miscdev_read,
+ .write = ecryptfs_miscdev_write,
+ .release = ecryptfs_miscdev_release,
+ .llseek = noop_llseek,
+};
+
+static struct miscdevice ecryptfs_miscdev = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "ecryptfs",
+ .fops = &ecryptfs_miscdev_fops
+};
+
+/**
+ * ecryptfs_init_ecryptfs_miscdev
+ *
+ * Messages sent to the userspace daemon from the kernel are placed on
+ * a queue associated with the daemon. The next read against the
+ * miscdev handle by that daemon will return the oldest message placed
+ * on the message queue for the daemon.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int __init ecryptfs_init_ecryptfs_miscdev(void)
+{
+ int rc;
+
+ atomic_set(&ecryptfs_num_miscdev_opens, 0);
+ rc = misc_register(&ecryptfs_miscdev);
+ if (rc)
+ printk(KERN_ERR "%s: Failed to register miscellaneous device "
+ "for communications with userspace daemons; rc = [%d]\n",
+ __func__, rc);
+ return rc;
+}
+
+/**
+ * ecryptfs_destroy_ecryptfs_miscdev
+ *
+ * All of the daemons must be exorcised prior to calling this
+ * function.
+ */
+void ecryptfs_destroy_ecryptfs_miscdev(void)
+{
+ BUG_ON(atomic_read(&ecryptfs_num_miscdev_opens) != 0);
+ misc_deregister(&ecryptfs_miscdev);
+}