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Subject[PATCH 1/2] eCryptfs: Public key; transport mechanism
This is a re-submission of the same public key patches (updated for
2.6.19-rc6-mm2) that were submitted for review a while back.

This is the transport code for public key functionality in
eCryptfs. It manages encryption/decryption request queues with a
transport mechanism. Currently, netlink is the only implemented
transport.

Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
---

fs/ecryptfs/ecryptfs_kernel.h | 101 ++++++++
fs/ecryptfs/messaging.c | 505 +++++++++++++++++++++++++++++++++++++++++
fs/ecryptfs/netlink.c | 255 +++++++++++++++++++++
include/linux/netlink.h | 1
4 files changed, 859 insertions(+), 3 deletions(-)
create mode 100644 fs/ecryptfs/messaging.c
create mode 100644 fs/ecryptfs/netlink.c

fa0a4f8f4601b6c005fcaa628f2d74c6466ec54d
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 870a65b..2bae036 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -6,6 +6,8 @@
* Copyright (C) 2001-2003 Stony Brook University
* Copyright (C) 2004-2006 International Business Machines Corp.
* Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ * Trevor S. Highland <trevor.highland@gmail.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 as
@@ -34,7 +36,7 @@ #include <linux/scatterlist.h>
/* Version verification for shared data structures w/ userspace */
#define ECRYPTFS_VERSION_MAJOR 0x00
#define ECRYPTFS_VERSION_MINOR 0x04
-#define ECRYPTFS_SUPPORTED_FILE_VERSION 0x01
+#define ECRYPTFS_SUPPORTED_FILE_VERSION 0x02
/* These flags indicate which features are supported by the kernel
* module; userspace tools such as the mount helper read
* ECRYPTFS_VERSIONING_MASK from a sysfs handle in order to determine
@@ -59,10 +61,24 @@ #define ECRYPTFS_PASSWORD_SIG_SIZE ECRYP
#define ECRYPTFS_MAX_KEY_BYTES 64
#define ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES 512
#define ECRYPTFS_DEFAULT_IV_BYTES 16
-#define ECRYPTFS_FILE_VERSION 0x01
+#define ECRYPTFS_FILE_VERSION 0x02
#define ECRYPTFS_DEFAULT_HEADER_EXTENT_SIZE 8192
#define ECRYPTFS_DEFAULT_EXTENT_SIZE 4096
#define ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE 8192
+#define ECRYPTFS_DEFAULT_MSG_CTX_ELEMS 32
+#define ECRYPTFS_DEFAULT_SEND_TIMEOUT HZ
+#define ECRYPTFS_MAX_MSG_CTX_TTL (HZ*3)
+#define ECRYPTFS_NLMSG_HELO 100
+#define ECRYPTFS_NLMSG_QUIT 101
+#define ECRYPTFS_NLMSG_REQUEST 102
+#define ECRYPTFS_NLMSG_RESPONSE 103
+#define ECRYPTFS_MAX_PKI_NAME_BYTES 16
+#define ECRYPTFS_DEFAULT_NUM_USERS 4
+#define ECRYPTFS_MAX_NUM_USERS 32768
+#define ECRYPTFS_TRANSPORT_NETLINK 0
+#define ECRYPTFS_TRANSPORT_CONNECTOR 1
+#define ECRYPTFS_TRANSPORT_RELAYFS 2
+#define ECRYPTFS_DEFAULT_TRANSPORT ECRYPTFS_TRANSPORT_NETLINK

#define RFC2440_CIPHER_DES3_EDE 0x02
#define RFC2440_CIPHER_CAST_5 0x03
@@ -76,6 +92,7 @@ #define RFC2440_CIPHER_CAST_6 0x0b
#define ECRYPTFS_SET_FLAG(flag_bit_vector, flag) (flag_bit_vector |= (flag))
#define ECRYPTFS_CLEAR_FLAG(flag_bit_vector, flag) (flag_bit_vector &= ~(flag))
#define ECRYPTFS_CHECK_FLAG(flag_bit_vector, flag) (flag_bit_vector & (flag))
+#define RFC2440_CIPHER_RSA 0x01

/**
* For convenience, we may need to pass around the encrypted session
@@ -113,6 +130,14 @@ #define ECRYPTFS_SESSION_KEY_ENCRYPTION_

enum ecryptfs_token_types {ECRYPTFS_PASSWORD, ECRYPTFS_PRIVATE_KEY};

+struct ecryptfs_private_key {
+ u32 key_size;
+ u32 data_len;
+ u8 signature[ECRYPTFS_PASSWORD_SIG_SIZE + 1];
+ char pki_type[ECRYPTFS_MAX_PKI_NAME_BYTES + 1];
+ u8 data[];
+};
+
/* May be a password or a private key */
struct ecryptfs_auth_tok {
u16 version; /* 8-bit major and 8-bit minor */
@@ -122,7 +147,7 @@ struct ecryptfs_auth_tok {
u8 reserved[32];
union {
struct ecryptfs_password password;
- /* Private key is in future eCryptfs releases */
+ struct ecryptfs_private_key private_key;
} token;
} __attribute__ ((packed));

@@ -177,8 +202,13 @@ #define ECRYPTFS_DEFAULT_CIPHER "aes"
#define ECRYPTFS_DEFAULT_KEY_BYTES 16
#define ECRYPTFS_DEFAULT_CHAINING_MODE CRYPTO_TFM_MODE_CBC
#define ECRYPTFS_DEFAULT_HASH "md5"
+#define ECRYPTFS_TAG_1_PACKET_TYPE 0x01
#define ECRYPTFS_TAG_3_PACKET_TYPE 0x8C
#define ECRYPTFS_TAG_11_PACKET_TYPE 0xED
+#define ECRYPTFS_TAG_64_PACKET_TYPE 0x40
+#define ECRYPTFS_TAG_65_PACKET_TYPE 0x41
+#define ECRYPTFS_TAG_66_PACKET_TYPE 0x42
+#define ECRYPTFS_TAG_67_PACKET_TYPE 0x43
#define MD5_DIGEST_SIZE 16

/**
@@ -271,6 +301,45 @@ struct ecryptfs_auth_tok_list_item {
struct ecryptfs_auth_tok auth_tok;
};

+struct ecryptfs_message {
+ u32 index;
+ u32 data_len;
+ u8 data[];
+};
+
+struct ecryptfs_msg_ctx {
+#define ECRYPTFS_MSG_CTX_STATE_FREE 0x0001
+#define ECRYPTFS_MSG_CTX_STATE_PENDING 0x0002
+#define ECRYPTFS_MSG_CTX_STATE_DONE 0x0003
+ u32 state;
+ unsigned int index;
+ unsigned int counter;
+ struct ecryptfs_message *msg;
+ struct task_struct *task;
+ struct list_head node;
+ struct mutex mux;
+};
+
+extern struct list_head ecryptfs_msg_ctx_free_list;
+extern struct list_head ecryptfs_msg_ctx_alloc_list;
+extern struct mutex ecryptfs_msg_ctx_lists_mux;
+
+#define ecryptfs_uid_hash(uid) \
+ hash_long((unsigned long)uid, ecryptfs_hash_buckets)
+extern struct hlist_head *ecryptfs_daemon_id_hash;
+extern struct mutex ecryptfs_daemon_id_hash_mux;
+extern int ecryptfs_hash_buckets;
+
+extern unsigned int ecryptfs_msg_counter;
+extern struct ecryptfs_msg_ctx *ecryptfs_msg_ctx_arr;
+extern unsigned int ecryptfs_transport;
+
+struct ecryptfs_daemon_id {
+ pid_t pid;
+ uid_t uid;
+ struct hlist_node id_chain;
+};
+
static inline struct ecryptfs_file_info *
ecryptfs_file_to_private(struct file *file)
{
@@ -391,6 +460,9 @@ extern struct super_operations ecryptfs_
extern struct dentry_operations ecryptfs_dops;
extern struct address_space_operations ecryptfs_aops;
extern int ecryptfs_verbosity;
+extern unsigned int ecryptfs_message_buf_len;
+extern signed long ecryptfs_message_wait_timeout;
+extern unsigned int ecryptfs_number_of_users;

extern struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
extern struct kmem_cache *ecryptfs_file_info_cache;
@@ -487,4 +559,27 @@ int ecryptfs_open_lower_file(struct file
struct vfsmount *lower_mnt, int flags);
int ecryptfs_close_lower_file(struct file *lower_file);

+int ecryptfs_process_helo(unsigned int transport, uid_t uid, pid_t pid);
+int ecryptfs_process_quit(uid_t uid, pid_t pid);
+int ecryptfs_process_response(struct ecryptfs_message *msg, pid_t pid, u32 seq);
+int ecryptfs_send_message(unsigned int transport, char *data, int data_len,
+ struct ecryptfs_msg_ctx **msg_ctx);
+int ecryptfs_wait_for_response(struct ecryptfs_msg_ctx *msg_ctx,
+ struct ecryptfs_message **emsg);
+int ecryptfs_init_messaging(unsigned int transport);
+void ecryptfs_release_messaging(unsigned int transport);
+
+int ecryptfs_send_netlink(char *data, int data_len,
+ struct ecryptfs_msg_ctx *msg_ctx, u16 msg_type,
+ u16 msg_flags, pid_t daemon_pid);
+int ecryptfs_init_netlink(void);
+void ecryptfs_release_netlink(void);
+
+int ecryptfs_send_connector(char *data, int data_len,
+ struct ecryptfs_msg_ctx *msg_ctx, u16 msg_type,
+ u16 msg_flags, pid_t daemon_pid);
+int ecryptfs_init_connector(void);
+void ecryptfs_release_connector(void);
+
+
#endif /* #ifndef ECRYPTFS_KERNEL_H */
diff --git a/fs/ecryptfs/messaging.c b/fs/ecryptfs/messaging.c
new file mode 100644
index 0000000..c22b32f
--- /dev/null
+++ b/fs/ecryptfs/messaging.c
@@ -0,0 +1,505 @@
+/**
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 2004-2006 International Business Machines Corp.
+ * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
+ * Tyler Hicks <tyhicks@ou.edu>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ */
+
+#include "ecryptfs_kernel.h"
+
+LIST_HEAD(ecryptfs_msg_ctx_free_list);
+LIST_HEAD(ecryptfs_msg_ctx_alloc_list);
+struct mutex ecryptfs_msg_ctx_lists_mux;
+
+struct hlist_head *ecryptfs_daemon_id_hash;
+struct mutex ecryptfs_daemon_id_hash_mux;
+int ecryptfs_hash_buckets;
+
+unsigned int ecryptfs_msg_counter;
+struct ecryptfs_msg_ctx *ecryptfs_msg_ctx_arr;
+
+/**
+ * ecryptfs_acquire_free_msg_ctx
+ * @msg_ctx: The context that was acquired from the free list
+ *
+ * Acquires a context element from the free list and locks the mutex
+ * on the context. Returns zero on success; non-zero on error or upon
+ * failure to acquire a free context element. Be sure to lock the
+ * list mutex before calling.
+ */
+static int ecryptfs_acquire_free_msg_ctx(struct ecryptfs_msg_ctx **msg_ctx)
+{
+ struct list_head *p;
+ int rc;
+
+ if (list_empty(&ecryptfs_msg_ctx_free_list)) {
+ ecryptfs_printk(KERN_WARNING, "The eCryptfs free "
+ "context list is empty. It may be helpful to "
+ "specify the ecryptfs_message_buf_len "
+ "parameter to be greater than the current "
+ "value of [%d]\n", ecryptfs_message_buf_len);
+ rc = -ENOMEM;
+ goto out;
+ }
+ list_for_each(p, &ecryptfs_msg_ctx_free_list) {
+ *msg_ctx = list_entry(p, struct ecryptfs_msg_ctx, node);
+ if (mutex_trylock(&(*msg_ctx)->mux)) {
+ (*msg_ctx)->task = current;
+ rc = 0;
+ goto out;
+ }
+ }
+ rc = -ENOMEM;
+out:
+ return rc;
+}
+
+/**
+ * ecryptfs_msg_ctx_free_to_alloc
+ * @msg_ctx: The context to move from the free list to the alloc list
+ *
+ * Be sure to lock the list mutex and the context mutex before
+ * calling.
+ */
+static void ecryptfs_msg_ctx_free_to_alloc(struct ecryptfs_msg_ctx *msg_ctx)
+{
+ list_move(&msg_ctx->node, &ecryptfs_msg_ctx_alloc_list);
+ msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_PENDING;
+ msg_ctx->counter = ++ecryptfs_msg_counter;
+}
+
+/**
+ * ecryptfs_msg_ctx_alloc_to_free
+ * @msg_ctx: The context to move from the alloc list to the free list
+ *
+ * Be sure to lock the list mutex and the context mutex before
+ * calling.
+ */
+static void ecryptfs_msg_ctx_alloc_to_free(struct ecryptfs_msg_ctx *msg_ctx)
+{
+ list_move(&(msg_ctx->node), &ecryptfs_msg_ctx_free_list);
+ if (msg_ctx->msg)
+ kfree(msg_ctx->msg);
+ msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_FREE;
+}
+
+/**
+ * ecryptfs_find_daemon_id
+ * @uid: The user id which maps to the desired daemon id
+ * @id: If return value is zero, points to the desired daemon id
+ * pointer
+ *
+ * Search the hash list for the given user id. Returns zero if the
+ * user id exists in the list; non-zero otherwise. The daemon id hash
+ * mutex should be held before calling this function.
+ */
+static int ecryptfs_find_daemon_id(uid_t uid, struct ecryptfs_daemon_id **id)
+{
+ struct hlist_node *elem;
+ int rc;
+
+ hlist_for_each_entry(*id, elem,
+ &ecryptfs_daemon_id_hash[ecryptfs_uid_hash(uid)],
+ id_chain) {
+ if ((*id)->uid == uid) {
+ rc = 0;
+ goto out;
+ }
+ }
+ rc = -EINVAL;
+out:
+ return rc;
+}
+
+static int ecryptfs_send_raw_message(unsigned int transport, u16 msg_type,
+ pid_t pid)
+{
+ int rc;
+
+ switch(transport) {
+ case ECRYPTFS_TRANSPORT_NETLINK:
+ rc = ecryptfs_send_netlink(NULL, 0, NULL, msg_type, 0, pid);
+ break;
+ case ECRYPTFS_TRANSPORT_CONNECTOR:
+ case ECRYPTFS_TRANSPORT_RELAYFS:
+ default:
+ rc = -ENOSYS;
+ }
+ return rc;
+}
+
+/**
+ * ecryptfs_process_helo
+ * @transport: The underlying transport (netlink, etc.)
+ * @uid: The user ID owner of the message
+ * @pid: The process ID for the userspace program that sent the
+ * message
+ *
+ * Adds the uid and pid values to the daemon id hash. If a uid
+ * already has a daemon pid registered, the daemon will be
+ * unregistered before the new daemon id is put into the hash list.
+ * Returns zero after adding a new daemon id to the hash list;
+ * non-zero otherwise.
+ */
+int ecryptfs_process_helo(unsigned int transport, uid_t uid, pid_t pid)
+{
+ struct ecryptfs_daemon_id *new_id;
+ struct ecryptfs_daemon_id *old_id;
+ int rc;
+
+ mutex_lock(&ecryptfs_daemon_id_hash_mux);
+ new_id = kmalloc(sizeof(*new_id), GFP_KERNEL);
+ if (!new_id) {
+ rc = -ENOMEM;
+ ecryptfs_printk(KERN_ERR, "Failed to allocate memory; unable "
+ "to register daemon [%d] for user\n", pid, uid);
+ goto unlock;
+ }
+ if (!ecryptfs_find_daemon_id(uid, &old_id)) {
+ printk(KERN_WARNING "Received request from user [%d] "
+ "to register daemon [%d]; unregistering daemon "
+ "[%d]\n", uid, pid, old_id->pid);
+ hlist_del(&old_id->id_chain);
+ rc = ecryptfs_send_raw_message(transport, ECRYPTFS_NLMSG_QUIT,
+ old_id->pid);
+ if (rc)
+ printk(KERN_WARNING "Failed to send QUIT "
+ "message to daemon [%d]; rc = [%d]\n",
+ old_id->pid, rc);
+ kfree(old_id);
+ }
+ new_id->uid = uid;
+ new_id->pid = pid;
+ hlist_add_head(&new_id->id_chain,
+ &ecryptfs_daemon_id_hash[ecryptfs_uid_hash(uid)]);
+ rc = 0;
+unlock:
+ mutex_unlock(&ecryptfs_daemon_id_hash_mux);
+ return rc;
+}
+
+/**
+ * ecryptfs_process_quit
+ * @uid: The user ID owner of the message
+ * @pid: The process ID for the userspace program that sent the
+ * message
+ *
+ * Deletes the corresponding daemon id for the given uid and pid, if
+ * it is the registered that is requesting the deletion. Returns zero
+ * after deleting the desired daemon id; non-zero otherwise.
+ */
+int ecryptfs_process_quit(uid_t uid, pid_t pid)
+{
+ struct ecryptfs_daemon_id *id;
+ int rc;
+
+ mutex_lock(&ecryptfs_daemon_id_hash_mux);
+ if (ecryptfs_find_daemon_id(uid, &id)) {
+ rc = -EINVAL;
+ ecryptfs_printk(KERN_ERR, "Received request from user [%d] to "
+ "unregister unrecognized daemon [%d]\n", uid,
+ pid);
+ goto unlock;
+ }
+ if (id->pid != pid) {
+ rc = -EINVAL;
+ ecryptfs_printk(KERN_WARNING, "Received request from user [%d] "
+ "with pid [%d] to unregister daemon [%d]\n",
+ uid, pid, id->pid);
+ goto unlock;
+ }
+ hlist_del(&id->id_chain);
+ kfree(id);
+ rc = 0;
+unlock:
+ mutex_unlock(&ecryptfs_daemon_id_hash_mux);
+ return rc;
+}
+
+/**
+ * ecryptfs_process_reponse
+ * @msg: The ecryptfs message received; the caller should sanity check
+ * msg->data_len
+ * @pid: The process ID of the userspace application that sent the
+ * message
+ * @seq: The sequence number of the message
+ *
+ * Processes a response message after sending a operation request to
+ * userspace. Returns zero upon delivery to desired context element;
+ * non-zero upon delivery failure or error.
+ */
+int ecryptfs_process_response(struct ecryptfs_message *msg, pid_t pid, u32 seq)
+{
+ struct ecryptfs_daemon_id *id;
+ struct ecryptfs_msg_ctx *msg_ctx;
+ int msg_size;
+ int rc;
+
+ if (msg->index >= ecryptfs_message_buf_len) {
+ rc = -EINVAL;
+ ecryptfs_printk(KERN_ERR, "Attempt to reference "
+ "context buffer at index [%d]; maximum "
+ "allowable is [%d]\n", msg->index,
+ (ecryptfs_message_buf_len - 1));
+ goto out;
+ }
+ msg_ctx = &ecryptfs_msg_ctx_arr[msg->index];
+ mutex_lock(&msg_ctx->mux);
+ if (ecryptfs_find_daemon_id(msg_ctx->task->euid, &id)) {
+ rc = -EBADMSG;
+ ecryptfs_printk(KERN_WARNING, "User [%d] received a "
+ "message response from process [%d] but does "
+ "not have a registered daemon\n",
+ msg_ctx->task->euid, pid);
+ goto wake_up;
+ }
+ if (id->pid != pid) {
+ rc = -EBADMSG;
+ ecryptfs_printk(KERN_ERR, "User [%d] received a "
+ "message response from an unrecognized "
+ "process [%d]\n", msg_ctx->task->euid, pid);
+ goto unlock;
+ }
+ if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_PENDING) {
+ rc = -EINVAL;
+ ecryptfs_printk(KERN_WARNING, "Desired context element is not "
+ "pending a response\n");
+ goto unlock;
+ } else if (msg_ctx->counter != seq) {
+ rc = -EINVAL;
+ ecryptfs_printk(KERN_WARNING, "Invalid message sequence; "
+ "expected [%d]; received [%d]\n",
+ msg_ctx->counter, seq);
+ goto unlock;
+ }
+ msg_size = sizeof(*msg) + msg->data_len;
+ msg_ctx->msg = kmalloc(msg_size, GFP_KERNEL);
+ if (!msg_ctx->msg) {
+ rc = -ENOMEM;
+ ecryptfs_printk(KERN_ERR, "Failed to allocate memory\n");
+ goto unlock;
+ }
+ memcpy(msg_ctx->msg, msg, msg_size);
+ msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_DONE;
+ rc = 0;
+wake_up:
+ wake_up_process(msg_ctx->task);
+unlock:
+ mutex_unlock(&msg_ctx->mux);
+out:
+ return rc;
+}
+
+/**
+ * ecryptfs_send_message
+ * @transport: The transport over which to send the message (i.e.,
+ * netlink)
+ * @data: The data to send
+ * @data_len: The length of data
+ * @msg_ctx: The message context allocated for the send
+ */
+int ecryptfs_send_message(unsigned int transport, char *data, int data_len,
+ struct ecryptfs_msg_ctx **msg_ctx)
+{
+ struct ecryptfs_daemon_id *id;
+ int rc;
+
+ mutex_lock(&ecryptfs_daemon_id_hash_mux);
+ if (ecryptfs_find_daemon_id(current->euid, &id)) {
+ mutex_unlock(&ecryptfs_daemon_id_hash_mux);
+ rc = -ENOTCONN;
+ ecryptfs_printk(KERN_ERR, "User [%d] does not have a daemon "
+ "registered\n", current->euid);
+ goto out;
+ }
+ mutex_unlock(&ecryptfs_daemon_id_hash_mux);
+ mutex_lock(&ecryptfs_msg_ctx_lists_mux);
+ rc = ecryptfs_acquire_free_msg_ctx(msg_ctx);
+ if (rc) {
+ mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
+ ecryptfs_printk(KERN_WARNING, "Could not claim a free "
+ "context element\n");
+ goto out;
+ }
+ ecryptfs_msg_ctx_free_to_alloc(*msg_ctx);
+ mutex_unlock(&(*msg_ctx)->mux);
+ mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
+ switch (transport) {
+ case ECRYPTFS_TRANSPORT_NETLINK:
+ rc = ecryptfs_send_netlink(data, data_len, *msg_ctx,
+ ECRYPTFS_NLMSG_REQUEST, 0, id->pid);
+ break;
+ case ECRYPTFS_TRANSPORT_CONNECTOR:
+ case ECRYPTFS_TRANSPORT_RELAYFS:
+ default:
+ rc = -ENOSYS;
+ }
+ if (rc) {
+ printk(KERN_ERR "Error attempting to send message to userspace "
+ "daemon; rc = [%d]\n", rc);
+ }
+out:
+ return rc;
+}
+
+/**
+ * ecryptfs_wait_for_response
+ * @msg_ctx: The context that was assigned when sending a message
+ * @msg: The incoming message from userspace; not set if rc != 0
+ *
+ * Sleeps until awaken by ecryptfs_receive_message or until the amount
+ * of time exceeds ecryptfs_message_wait_timeout. If zero is
+ * returned, msg will point to a valid message from userspace; a
+ * non-zero value is returned upon failure to receive a message or an
+ * error occurs.
+ */
+int ecryptfs_wait_for_response(struct ecryptfs_msg_ctx *msg_ctx,
+ struct ecryptfs_message **msg)
+{
+ signed long timeout = ecryptfs_message_wait_timeout * HZ;
+ int rc = 0;
+
+sleep:
+ timeout = schedule_timeout_interruptible(timeout);
+ mutex_lock(&ecryptfs_msg_ctx_lists_mux);
+ mutex_lock(&msg_ctx->mux);
+ if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_DONE) {
+ if (timeout) {
+ mutex_unlock(&msg_ctx->mux);
+ mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
+ goto sleep;
+ }
+ rc = -ENOMSG;
+ } else {
+ *msg = msg_ctx->msg;
+ msg_ctx->msg = NULL;
+ }
+ ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
+ mutex_unlock(&msg_ctx->mux);
+ mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
+ return rc;
+}
+
+int ecryptfs_init_messaging(unsigned int transport)
+{
+ int i;
+ int rc = 0;
+
+ if (ecryptfs_number_of_users > ECRYPTFS_MAX_NUM_USERS) {
+ ecryptfs_number_of_users = ECRYPTFS_MAX_NUM_USERS;
+ ecryptfs_printk(KERN_WARNING, "Specified number of users is "
+ "too large, defaulting to [%d] users\n",
+ ecryptfs_number_of_users);
+ }
+ mutex_init(&ecryptfs_daemon_id_hash_mux);
+ mutex_lock(&ecryptfs_daemon_id_hash_mux);
+ ecryptfs_hash_buckets = 0;
+ while (ecryptfs_number_of_users >> ++ecryptfs_hash_buckets);
+ ecryptfs_daemon_id_hash = kmalloc(sizeof(struct hlist_head)
+ * ecryptfs_hash_buckets, GFP_KERNEL);
+ if (!ecryptfs_daemon_id_hash) {
+ rc = -ENOMEM;
+ ecryptfs_printk(KERN_ERR, "Failed to allocate memory\n");
+ goto out;
+ }
+ for (i = 0; i < ecryptfs_hash_buckets; i++)
+ INIT_HLIST_HEAD(&ecryptfs_daemon_id_hash[i]);
+ mutex_unlock(&ecryptfs_daemon_id_hash_mux);
+
+ ecryptfs_msg_ctx_arr = kmalloc((sizeof(struct ecryptfs_msg_ctx)
+ * ecryptfs_message_buf_len), GFP_KERNEL);
+ if (!ecryptfs_msg_ctx_arr) {
+ rc = -ENOMEM;
+ ecryptfs_printk(KERN_ERR, "Failed to allocate memory\n");
+ goto out;
+ }
+ mutex_init(&ecryptfs_msg_ctx_lists_mux);
+ mutex_lock(&ecryptfs_msg_ctx_lists_mux);
+ ecryptfs_msg_counter = 0;
+ for (i = 0; i < ecryptfs_message_buf_len; i++) {
+ INIT_LIST_HEAD(&ecryptfs_msg_ctx_arr[i].node);
+ mutex_init(&ecryptfs_msg_ctx_arr[i].mux);
+ mutex_lock(&ecryptfs_msg_ctx_arr[i].mux);
+ ecryptfs_msg_ctx_arr[i].index = i;
+ ecryptfs_msg_ctx_arr[i].state = ECRYPTFS_MSG_CTX_STATE_FREE;
+ ecryptfs_msg_ctx_arr[i].counter = 0;
+ ecryptfs_msg_ctx_arr[i].task = NULL;
+ ecryptfs_msg_ctx_arr[i].msg = NULL;
+ list_add_tail(&ecryptfs_msg_ctx_arr[i].node,
+ &ecryptfs_msg_ctx_free_list);
+ mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux);
+ }
+ mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
+ switch(transport) {
+ case ECRYPTFS_TRANSPORT_NETLINK:
+ rc = ecryptfs_init_netlink();
+ if (rc)
+ ecryptfs_release_messaging(transport);
+ break;
+ case ECRYPTFS_TRANSPORT_CONNECTOR:
+ case ECRYPTFS_TRANSPORT_RELAYFS:
+ default:
+ rc = -ENOSYS;
+ }
+out:
+ return rc;
+}
+
+void ecryptfs_release_messaging(unsigned int transport)
+{
+ if (ecryptfs_msg_ctx_arr) {
+ int i;
+
+ mutex_lock(&ecryptfs_msg_ctx_lists_mux);
+ for (i = 0; i < ecryptfs_message_buf_len; i++) {
+ mutex_lock(&ecryptfs_msg_ctx_arr[i].mux);
+ if (ecryptfs_msg_ctx_arr[i].msg)
+ kfree(ecryptfs_msg_ctx_arr[i].msg);
+ mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux);
+ }
+ kfree(ecryptfs_msg_ctx_arr);
+ mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
+ }
+ if (ecryptfs_daemon_id_hash) {
+ struct hlist_node *elem;
+ struct ecryptfs_daemon_id *id;
+ int i;
+
+ mutex_lock(&ecryptfs_daemon_id_hash_mux);
+ for (i = 0; i < ecryptfs_hash_buckets; i++) {
+ hlist_for_each_entry(id, elem,
+ &ecryptfs_daemon_id_hash[i],
+ id_chain) {
+ hlist_del(elem);
+ kfree(id);
+ }
+ }
+ kfree(ecryptfs_daemon_id_hash);
+ mutex_unlock(&ecryptfs_daemon_id_hash_mux);
+ }
+ switch(transport) {
+ case ECRYPTFS_TRANSPORT_NETLINK:
+ ecryptfs_release_netlink();
+ break;
+ case ECRYPTFS_TRANSPORT_CONNECTOR:
+ case ECRYPTFS_TRANSPORT_RELAYFS:
+ default:
+ break;
+ }
+ return;
+}
diff --git a/fs/ecryptfs/netlink.c b/fs/ecryptfs/netlink.c
new file mode 100644
index 0000000..aba061d
--- /dev/null
+++ b/fs/ecryptfs/netlink.c
@@ -0,0 +1,255 @@
+/**
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 2004-2006 International Business Machines Corp.
+ * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
+ * Tyler Hicks <tyhicks@ou.edu>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ */
+
+#include <net/sock.h>
+#include <linux/hash.h>
+#include <linux/random.h>
+#include "ecryptfs_kernel.h"
+
+static struct sock *ecryptfs_nl_sock;
+
+/**
+ * ecryptfs_send_netlink
+ * @data: The data to include as the payload
+ * @data_len: The byte count of the data
+ * @msg_ctx: The netlink context that will be used to handle the
+ * response message
+ * @msg_type: The type of netlink message to send
+ * @msg_flags: The flags to include in the netlink header
+ * @daemon_pid: The process id of the daemon to send the message to
+ *
+ * Sends the data to the specified daemon pid and uses the netlink
+ * context element to store the data needed for validation upon
+ * receiving the response. The data and the netlink context can be
+ * null if just sending a netlink header is sufficient. Returns zero
+ * upon sending the message; non-zero upon error.
+ */
+int ecryptfs_send_netlink(char *data, int data_len,
+ struct ecryptfs_msg_ctx *msg_ctx, u16 msg_type,
+ u16 msg_flags, pid_t daemon_pid)
+{
+ struct sk_buff *skb;
+ struct nlmsghdr *nlh;
+ struct ecryptfs_message *msg;
+ size_t payload_len;
+ int rc;
+
+ payload_len = ((data && data_len) ? (sizeof(*msg) + data_len) : 0);
+ skb = alloc_skb(NLMSG_SPACE(payload_len), GFP_KERNEL);
+ if (!skb) {
+ rc = -ENOMEM;
+ ecryptfs_printk(KERN_ERR, "Failed to allocate socket buffer\n");
+ goto out;
+ }
+ nlh = NLMSG_PUT(skb, daemon_pid, msg_ctx ? msg_ctx->counter : 0,
+ msg_type, payload_len);
+ nlh->nlmsg_flags = msg_flags;
+ if (msg_ctx && payload_len) {
+ msg = (struct ecryptfs_message *)NLMSG_DATA(nlh);
+ msg->index = msg_ctx->index;
+ msg->data_len = data_len;
+ memcpy(msg->data, data, data_len);
+ }
+ rc = netlink_unicast(ecryptfs_nl_sock, skb, daemon_pid, 0);
+ if (rc < 0) {
+ ecryptfs_printk(KERN_ERR, "Failed to send eCryptfs netlink "
+ "message; rc = [%d]\n", rc);
+ goto out;
+ }
+ rc = 0;
+ goto out;
+nlmsg_failure:
+ rc = -EMSGSIZE;
+ kfree_skb(skb);
+out:
+ return rc;
+}
+
+/**
+ * ecryptfs_process_nl_reponse
+ * @skb: The socket buffer containing the netlink message of state
+ * RESPONSE
+ *
+ * Processes a response message after sending a operation request to
+ * userspace. Attempts to assign the msg to a netlink context element
+ * at the index specified in the msg. The sk_buff and nlmsghdr must
+ * be validated before this function. Returns zero upon delivery to
+ * desired context element; non-zero upon delivery failure or error.
+ */
+static int ecryptfs_process_nl_response(struct sk_buff *skb)
+{
+ struct nlmsghdr *nlh = (struct nlmsghdr*)skb->data;
+ struct ecryptfs_message *msg = NLMSG_DATA(nlh);
+ int rc;
+
+ if (skb->len - NLMSG_HDRLEN - sizeof(*msg) != msg->data_len) {
+ rc = -EINVAL;
+ ecryptfs_printk(KERN_ERR, "Received netlink message with "
+ "incorrectly specified data length\n");
+ goto out;
+ }
+ rc = ecryptfs_process_response(msg, NETLINK_CREDS(skb)->pid,
+ nlh->nlmsg_seq);
+ if (rc)
+ printk(KERN_ERR
+ "Error processing response message; rc = [%d]\n", rc);
+out:
+ return rc;
+}
+
+/**
+ * ecryptfs_process_nl_helo
+ * @skb: The socket buffer containing the nlmsghdr in HELO state
+ *
+ * Gets uid and pid of the skb and adds the values to the daemon id
+ * hash. Returns zero after adding a new daemon id to the hash list;
+ * non-zero otherwise.
+ */
+static int ecryptfs_process_nl_helo(struct sk_buff *skb)
+{
+ int rc;
+
+ rc = ecryptfs_process_helo(ECRYPTFS_TRANSPORT_NETLINK,
+ NETLINK_CREDS(skb)->uid,
+ NETLINK_CREDS(skb)->pid);
+ if (rc)
+ printk(KERN_WARNING "Error processing HELO; rc = [%d]\n", rc);
+ return rc;
+}
+
+/**
+ * ecryptfs_process_nl_quit
+ * @skb: The socket buffer containing the nlmsghdr in QUIT state
+ *
+ * Gets uid and pid of the skb and deletes the corresponding daemon
+ * id, if it is the registered that is requesting the
+ * deletion. Returns zero after deleting the desired daemon id;
+ * non-zero otherwise.
+ */
+static int ecryptfs_process_nl_quit(struct sk_buff *skb)
+{
+ int rc;
+
+ rc = ecryptfs_process_quit(NETLINK_CREDS(skb)->uid,
+ NETLINK_CREDS(skb)->pid);
+ if (rc)
+ printk(KERN_WARNING
+ "Error processing QUIT message; rc = [%d]\n", rc);
+ return rc;
+}
+
+/**
+ * ecryptfs_receive_nl_message
+ *
+ * Callback function called by netlink system when a message arrives.
+ * If the message looks to be valid, then an attempt is made to assign
+ * it to its desired netlink context element and wake up the process
+ * that is waiting for a response.
+ */
+static void ecryptfs_receive_nl_message(struct sock *sk, int len)
+{
+ struct sk_buff *skb;
+ struct nlmsghdr *nlh;
+ int rc = 0; /* skb_recv_datagram requires this */
+
+receive:
+ skb = skb_recv_datagram(sk, 0, 0, &rc);
+ if (rc == -EINTR)
+ goto receive;
+ else if (rc < 0) {
+ ecryptfs_printk(KERN_ERR, "Error occurred while "
+ "receiving eCryptfs netlink message; "
+ "rc = [%d]\n", rc);
+ return;
+ }
+ nlh = (struct nlmsghdr *)skb->data;
+ if (!NLMSG_OK(nlh, skb->len)) {
+ ecryptfs_printk(KERN_ERR, "Received corrupt netlink "
+ "message\n");
+ goto free;
+ }
+ switch (nlh->nlmsg_type) {
+ case ECRYPTFS_NLMSG_RESPONSE:
+ if (ecryptfs_process_nl_response(skb)) {
+ ecryptfs_printk(KERN_WARNING, "Failed to "
+ "deliver netlink response to "
+ "requesting operation\n");
+ }
+ break;
+ case ECRYPTFS_NLMSG_HELO:
+ if (ecryptfs_process_nl_helo(skb)) {
+ ecryptfs_printk(KERN_WARNING, "Failed to "
+ "fulfill HELO request\n");
+ }
+ break;
+ case ECRYPTFS_NLMSG_QUIT:
+ if (ecryptfs_process_nl_quit(skb)) {
+ ecryptfs_printk(KERN_WARNING, "Failed to "
+ "fulfill QUIT request\n");
+ }
+ break;
+ default:
+ ecryptfs_printk(KERN_WARNING, "Dropping netlink "
+ "message of unrecognized type [%d]\n",
+ nlh->nlmsg_type);
+ break;
+ }
+free:
+ kfree_skb(skb);
+}
+
+/**
+ * ecryptfs_init_netlink
+ *
+ * Initializes the daemon id hash list, netlink context array, and
+ * necessary locks. Returns zero upon success; non-zero upon error.
+ */
+int ecryptfs_init_netlink(void)
+{
+ int rc;
+
+ ecryptfs_nl_sock = netlink_kernel_create(NETLINK_ECRYPTFS, 0,
+ ecryptfs_receive_nl_message,
+ THIS_MODULE);
+ if (!ecryptfs_nl_sock) {
+ rc = -EIO;
+ ecryptfs_printk(KERN_ERR, "Failed to create netlink socket\n");
+ goto out;
+ }
+ ecryptfs_nl_sock->sk_sndtimeo = ECRYPTFS_DEFAULT_SEND_TIMEOUT;
+ rc = 0;
+out:
+ return rc;
+}
+
+/**
+ * ecryptfs_release_netlink
+ *
+ * Frees all memory used by the netlink context array and releases the
+ * netlink socket.
+ */
+void ecryptfs_release_netlink(void)
+{
+ if (ecryptfs_nl_sock && ecryptfs_nl_sock->sk_socket)
+ sock_release(ecryptfs_nl_sock->sk_socket);
+ ecryptfs_nl_sock = NULL;
+}
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index b3b9b60..2a20f48 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -23,6 +23,7 @@ #define NETLINK_KOBJECT_UEVENT 15 /* Ker
#define NETLINK_GENERIC 16
/* leave room for NETLINK_DM (DM Events) */
#define NETLINK_SCSITRANSPORT 18 /* SCSI Transports */
+#define NETLINK_ECRYPTFS 19

#define MAX_LINKS 32

--
1.3.3
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