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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * eCryptfs: Linux filesystem encryption layer
  * In-kernel key management code.  Includes functions to parse and
  * write authentication token-related packets with the underlying
  * file.
  *
  * Copyright (C) 2004-2006 International Business Machines Corp.
  *   Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
  *              Michael C. Thompson <mcthomps@us.ibm.com>
  *              Trevor S. Highland <trevor.highland@gmail.com>
  */
 
 #include <crypto/hash.h>
 #include <crypto/skcipher.h>
 #include <linux/string.h>
 #include <linux/pagemap.h>
 #include <linux/key.h>
 #include <linux/random.h>
 #include <linux/scatterlist.h>
 #include <linux/slab.h>
 #include "ecryptfs_kernel.h"
 
 /*
  * request_key returned an error instead of a valid key address;
  * determine the type of error, make appropriate log entries, and
  * return an error code.
  */
 static int process_request_key_err(long err_code)
 {
     int rc = 0;
 
     switch (err_code) {
     case -ENOKEY:
         ecryptfs_printk(KERN_WARNING, "No key\n");
         rc = -ENOENT;
         break;
     case -EKEYEXPIRED:
         ecryptfs_printk(KERN_WARNING, "Key expired\n");
         rc = -ETIME;
         break;
     case -EKEYREVOKED:
         ecryptfs_printk(KERN_WARNING, "Key revoked\n");
         rc = -EINVAL;
         break;
     default:
         ecryptfs_printk(KERN_WARNING, "Unknown error code: "
                 "[0x%.16lx]\n", err_code);
         rc = -EINVAL;
     }
     return rc;
 }
 
 static int process_find_global_auth_tok_for_sig_err(int err_code)
 {
     int rc = err_code;
 
     switch (err_code) {
     case -ENOENT:
         ecryptfs_printk(KERN_WARNING, "Missing auth tok\n");
         break;
     case -EINVAL:
         ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n");
         break;
     default:
         rc = process_request_key_err(err_code);
         break;
     }
     return rc;
 }
 
 /**
  * ecryptfs_parse_packet_length
  * @data: Pointer to memory containing length at offset
  * @size: This function writes the decoded size to this memory
  *        address; zero on error
  * @length_size: The number of bytes occupied by the encoded length
  *
  * Returns zero on success; non-zero on error
  */
 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
                  size_t *length_size)
 {
     int rc = 0;
 
     (*length_size) = 0;
     (*size) = 0;
     if (data[0] < 192) {
         /* One-byte length */
         (*size) = data[0];
         (*length_size) = 1;
     } else if (data[0] < 224) {
         /* Two-byte length */
         (*size) = (data[0] - 192) * 256;
         (*size) += data[1] + 192;
         (*length_size) = 2;
     } else if (data[0] == 255) {
         /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
         ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
                 "supported\n");
         rc = -EINVAL;
         goto out;
     } else {
         ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
         rc = -EINVAL;
         goto out;
     }
 out:
     return rc;
 }
 
 /**
  * ecryptfs_write_packet_length
  * @dest: The byte array target into which to write the length. Must
  *        have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated.
  * @size: The length to write.
  * @packet_size_length: The number of bytes used to encode the packet
  *                      length is written to this address.
  *
  * Returns zero on success; non-zero on error.
  */
 int ecryptfs_write_packet_length(char *dest, size_t size,
                  size_t *packet_size_length)
 {
     int rc = 0;
 
     if (size < 192) {
         dest[0] = size;
         (*packet_size_length) = 1;
     } else if (size < 65536) {
         dest[0] = (((size - 192) / 256) + 192);
         dest[1] = ((size - 192) % 256);
         (*packet_size_length) = 2;
     } else {
         /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
         rc = -EINVAL;
         ecryptfs_printk(KERN_WARNING,
                 "Unsupported packet size: [%zd]\n", size);
     }
     return rc;
 }
 
 static int
 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
             char **packet, size_t *packet_len)
 {
     size_t i = 0;
     size_t data_len;
     size_t packet_size_len;
     char *message;
     int rc;
 
     /*
      *              ***** TAG 64 Packet Format *****
      *    | Content Type                       | 1 byte       |
      *    | Key Identifier Size                | 1 or 2 bytes |
      *    | Key Identifier                     | arbitrary    |
      *    | Encrypted File Encryption Key Size | 1 or 2 bytes |
      *    | Encrypted File Encryption Key      | arbitrary    |
      */
     data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
             + session_key->encrypted_key_size);
     *packet = kmalloc(data_len, GFP_KERNEL);
     message = *packet;
     if (!message) {
         ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
         rc = -ENOMEM;
         goto out;
     }
     message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
     rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
                       &packet_size_len);
     if (rc) {
         ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
                 "header; cannot generate packet length\n");
         goto out;
     }
     i += packet_size_len;
     memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
     i += ECRYPTFS_SIG_SIZE_HEX;
     rc = ecryptfs_write_packet_length(&message[i],
                       session_key->encrypted_key_size,
                       &packet_size_len);
     if (rc) {
         ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
                 "header; cannot generate packet length\n");
         goto out;
     }
     i += packet_size_len;
     memcpy(&message[i], session_key->encrypted_key,
            session_key->encrypted_key_size);
     i += session_key->encrypted_key_size;
     *packet_len = i;
 out:
     return rc;
 }
 
 static int
 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
             struct ecryptfs_message *msg)
 {
     size_t i = 0;
     char *data;
     size_t data_len;
     size_t m_size;
     size_t message_len;
     u16 checksum = 0;
     u16 expected_checksum = 0;
     int rc;
 
     /*
      *              ***** TAG 65 Packet Format *****
      *         | Content Type             | 1 byte       |
      *         | Status Indicator         | 1 byte       |
      *         | File Encryption Key Size | 1 or 2 bytes |
      *         | File Encryption Key      | arbitrary    |
      */
     message_len = msg->data_len;
     data = msg->data;
     if (message_len < 4) {
         rc = -EIO;
         goto out;
     }
     if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
         ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
         rc = -EIO;
         goto out;
     }
     if (data[i++]) {
         ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
                 "[%d]\n", data[i-1]);
         rc = -EIO;
         goto out;
     }
     rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
     if (rc) {
         ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
                 "rc = [%d]\n", rc);
         goto out;
     }
     i += data_len;
     if (message_len < (i + m_size)) {
         ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd "
                 "is shorter than expected\n");
         rc = -EIO;
         goto out;
     }
     if (m_size < 3) {
         ecryptfs_printk(KERN_ERR,
                 "The decrypted key is not long enough to "
                 "include a cipher code and checksum\n");
         rc = -EIO;
         goto out;
     }
     *cipher_code = data[i++];
     /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
     session_key->decrypted_key_size = m_size - 3;
     if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
         ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
                 "the maximum key size [%d]\n",
                 session_key->decrypted_key_size,
                 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
         rc = -EIO;
         goto out;
     }
     memcpy(session_key->decrypted_key, &data[i],
            session_key->decrypted_key_size);
     i += session_key->decrypted_key_size;
     expected_checksum += (unsigned char)(data[i++]) << 8;
     expected_checksum += (unsigned char)(data[i++]);
     for (i = 0; i < session_key->decrypted_key_size; i++)
         checksum += session_key->decrypted_key[i];
     if (expected_checksum != checksum) {
         ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
                 "encryption  key; expected [%x]; calculated "
                 "[%x]\n", expected_checksum, checksum);
         rc = -EIO;
     }
 out:
     return rc;
 }
 
 
 static int
 write_tag_66_packet(char *signature, u8 cipher_code,
             struct ecryptfs_crypt_stat *crypt_stat, char **packet,
             size_t *packet_len)
 {
     size_t i = 0;
     size_t j;
     size_t data_len;
     size_t checksum = 0;
     size_t packet_size_len;
     char *message;
     int rc;
 
     /*
      *              ***** TAG 66 Packet Format *****
      *         | Content Type             | 1 byte       |
      *         | Key Identifier Size      | 1 or 2 bytes |
      *         | Key Identifier           | arbitrary    |
      *         | File Encryption Key Size | 1 or 2 bytes |
      *         | File Encryption Key      | arbitrary    |
      */
     data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
     *packet = kmalloc(data_len, GFP_KERNEL);
     message = *packet;
     if (!message) {
         ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
         rc = -ENOMEM;
         goto out;
     }
     message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
     rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
                       &packet_size_len);
     if (rc) {
         ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
                 "header; cannot generate packet length\n");
         goto out;
     }
     i += packet_size_len;
     memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
     i += ECRYPTFS_SIG_SIZE_HEX;
     /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
     rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
                       &packet_size_len);
     if (rc) {
         ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
                 "header; cannot generate packet length\n");
         goto out;
     }
     i += packet_size_len;
     message[i++] = cipher_code;
     memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
     i += crypt_stat->key_size;
     for (j = 0; j < crypt_stat->key_size; j++)
         checksum += crypt_stat->key[j];
     message[i++] = (checksum / 256) % 256;
     message[i++] = (checksum % 256);
     *packet_len = i;
 out:
     return rc;
 }
 
 static int
 parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
             struct ecryptfs_message *msg)
 {
     size_t i = 0;
     char *data;
     size_t data_len;
     size_t message_len;
     int rc;
 
     /*
      *              ***** TAG 65 Packet Format *****
      *    | Content Type                       | 1 byte       |
      *    | Status Indicator                   | 1 byte       |
      *    | Encrypted File Encryption Key Size | 1 or 2 bytes |
      *    | Encrypted File Encryption Key      | arbitrary    |
      */
     message_len = msg->data_len;
     data = msg->data;
     /* verify that everything through the encrypted FEK size is present */
     if (message_len < 4) {
         rc = -EIO;
         printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
                "message length is [%d]\n", __func__, message_len, 4);
         goto out;
     }
     if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
         rc = -EIO;
         printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
                __func__);
         goto out;
     }
     if (data[i++]) {
         rc = -EIO;
         printk(KERN_ERR "%s: Status indicator has non zero "
                "value [%d]\n", __func__, data[i-1]);
 
         goto out;
     }
     rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
                       &data_len);
     if (rc) {
         ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
                 "rc = [%d]\n", rc);
         goto out;
     }
     i += data_len;
     if (message_len < (i + key_rec->enc_key_size)) {
         rc = -EIO;
         printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
                __func__, message_len, (i + key_rec->enc_key_size));
         goto out;
     }
     if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
         rc = -EIO;
         printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
                "the maximum key size [%d]\n", __func__,
                key_rec->enc_key_size,
                ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
         goto out;
     }
     memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
 out:
     return rc;
 }
 
 /**
  * ecryptfs_verify_version
  * @version: The version number to confirm
  *
  * Returns zero on good version; non-zero otherwise
  */
 static int ecryptfs_verify_version(u16 version)
 {
     int rc = 0;
     unsigned char major;
     unsigned char minor;
 
     major = ((version >> 8) & 0xFF);
     minor = (version & 0xFF);
     if (major != ECRYPTFS_VERSION_MAJOR) {
         ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
                 "Expected [%d]; got [%d]\n",
                 ECRYPTFS_VERSION_MAJOR, major);
         rc = -EINVAL;
         goto out;
     }
     if (minor != ECRYPTFS_VERSION_MINOR) {
         ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
                 "Expected [%d]; got [%d]\n",
                 ECRYPTFS_VERSION_MINOR, minor);
         rc = -EINVAL;
         goto out;
     }
 out:
     return rc;
 }
 
 /**
  * ecryptfs_verify_auth_tok_from_key
  * @auth_tok_key: key containing the authentication token
  * @auth_tok: authentication token
  *
  * Returns zero on valid auth tok; -EINVAL if the payload is invalid; or
  * -EKEYREVOKED if the key was revoked before we acquired its semaphore.
  */
 static int
 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
                   struct ecryptfs_auth_tok **auth_tok)
 {
     int rc = 0;
 
     (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
     if (IS_ERR(*auth_tok)) {
         rc = PTR_ERR(*auth_tok);
         *auth_tok = NULL;
         goto out;
     }
 
     if (ecryptfs_verify_version((*auth_tok)->version)) {
         printk(KERN_ERR "Data structure version mismatch. Userspace "
                "tools must match eCryptfs kernel module with major "
                "version [%d] and minor version [%d]\n",
                ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
         rc = -EINVAL;
         goto out;
     }
     if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
         && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
         printk(KERN_ERR "Invalid auth_tok structure "
                "returned from key query\n");
         rc = -EINVAL;
         goto out;
     }
 out:
     return rc;
 }
 
 static int
 ecryptfs_find_global_auth_tok_for_sig(
     struct key **auth_tok_key,
     struct ecryptfs_auth_tok **auth_tok,
     struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
 {
     struct ecryptfs_global_auth_tok *walker;
     int rc = 0;
 
     (*auth_tok_key) = NULL;
     (*auth_tok) = NULL;
     mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
     list_for_each_entry(walker,
                 &mount_crypt_stat->global_auth_tok_list,
                 mount_crypt_stat_list) {
         if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
             continue;
 
         if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
             rc = -EINVAL;
             goto out;
         }
 
         rc = key_validate(walker->global_auth_tok_key);
         if (rc) {
             if (rc == -EKEYEXPIRED)
                 goto out;
             goto out_invalid_auth_tok;
         }
 
         down_write(&(walker->global_auth_tok_key->sem));
         rc = ecryptfs_verify_auth_tok_from_key(
                 walker->global_auth_tok_key, auth_tok);
         if (rc)
             goto out_invalid_auth_tok_unlock;
 
         (*auth_tok_key) = walker->global_auth_tok_key;
         key_get(*auth_tok_key);
         goto out;
     }
     rc = -ENOENT;
     goto out;
 out_invalid_auth_tok_unlock:
     up_write(&(walker->global_auth_tok_key->sem));
 out_invalid_auth_tok:
     printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
     walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
     key_put(walker->global_auth_tok_key);
     walker->global_auth_tok_key = NULL;
 out:
     mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
     return rc;
 }
 
 /**
  * ecryptfs_find_auth_tok_for_sig
  * @auth_tok_key: key containing the authentication token
  * @auth_tok: Set to the matching auth_tok; NULL if not found
  * @mount_crypt_stat: inode crypt_stat crypto context
  * @sig: Sig of auth_tok to find
  *
  * For now, this function simply looks at the registered auth_tok's
  * linked off the mount_crypt_stat, so all the auth_toks that can be
  * used must be registered at mount time. This function could
  * potentially try a lot harder to find auth_tok's (e.g., by calling
  * out to ecryptfsd to dynamically retrieve an auth_tok object) so
  * that static registration of auth_tok's will no longer be necessary.
  *
  * Returns zero on no error; non-zero on error
  */
 static int
 ecryptfs_find_auth_tok_for_sig(
     struct key **auth_tok_key,
     struct ecryptfs_auth_tok **auth_tok,
     struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
     char *sig)
 {
     int rc = 0;
 
     rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
                            mount_crypt_stat, sig);
     if (rc == -ENOENT) {
         /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
          * mount_crypt_stat structure, we prevent to use auth toks that
          * are not inserted through the ecryptfs_add_global_auth_tok
          * function.
          */
         if (mount_crypt_stat->flags
                 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
             return -EINVAL;
 
         rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
                                sig);
     }
     return rc;
 }
 
 /*
  * write_tag_70_packet can gobble a lot of stack space. We stuff most
  * of the function's parameters in a kmalloc'd struct to help reduce
  * eCryptfs' overall stack usage.
  */
 struct ecryptfs_write_tag_70_packet_silly_stack {
     u8 cipher_code;
     size_t max_packet_size;
     size_t packet_size_len;
     size_t block_aligned_filename_size;
     size_t block_size;
     size_t i;
     size_t j;
     size_t num_rand_bytes;
     struct mutex *tfm_mutex;
     char *block_aligned_filename;
     struct ecryptfs_auth_tok *auth_tok;
     struct scatterlist src_sg[2];
     struct scatterlist dst_sg[2];
     struct crypto_skcipher *skcipher_tfm;
     struct skcipher_request *skcipher_req;
     char iv[ECRYPTFS_MAX_IV_BYTES];
     char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
     char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
     struct crypto_shash *hash_tfm;
     struct shash_desc *hash_desc;
 };
 
 /*
  * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
  * @filename: NULL-terminated filename string
  *
  * This is the simplest mechanism for achieving filename encryption in
  * eCryptfs. It encrypts the given filename with the mount-wide
  * filename encryption key (FNEK) and stores it in a packet to @dest,
  * which the callee will encode and write directly into the dentry
  * name.
  */
 int
 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
                  size_t *packet_size,
                  struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
                  char *filename, size_t filename_size)
 {
     struct ecryptfs_write_tag_70_packet_silly_stack *s;
     struct key *auth_tok_key = NULL;
     int rc = 0;
 
     s = kzalloc(sizeof(*s), GFP_KERNEL);
     if (!s)
         return -ENOMEM;
 
     (*packet_size) = 0;
     rc = ecryptfs_find_auth_tok_for_sig(
         &auth_tok_key,
         &s->auth_tok, mount_crypt_stat,
         mount_crypt_stat->global_default_fnek_sig);
     if (rc) {
         printk(KERN_ERR "%s: Error attempting to find auth tok for "
                "fnek sig [%s]; rc = [%d]\n", __func__,
                mount_crypt_stat->global_default_fnek_sig, rc);
         goto out;
     }
     rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
         &s->skcipher_tfm,
         &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
     if (unlikely(rc)) {
         printk(KERN_ERR "Internal error whilst attempting to get "
                "tfm and mutex for cipher name [%s]; rc = [%d]\n",
                mount_crypt_stat->global_default_fn_cipher_name, rc);
         goto out;
     }
     mutex_lock(s->tfm_mutex);
     s->block_size = crypto_skcipher_blocksize(s->skcipher_tfm);
     /* Plus one for the \0 separator between the random prefix
      * and the plaintext filename */
     s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
     s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
     if ((s->block_aligned_filename_size % s->block_size) != 0) {
         s->num_rand_bytes += (s->block_size
                       - (s->block_aligned_filename_size
                      % s->block_size));
         s->block_aligned_filename_size = (s->num_rand_bytes
                           + filename_size);
     }
     /* Octet 0: Tag 70 identifier
      * Octets 1-N1: Tag 70 packet size (includes cipher identifier
      *              and block-aligned encrypted filename size)
      * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
      * Octet N2-N3: Cipher identifier (1 octet)
      * Octets N3-N4: Block-aligned encrypted filename
      *  - Consists of a minimum number of random characters, a \0
      *    separator, and then the filename */
     s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE
                   + s->block_aligned_filename_size);
     if (!dest) {
         (*packet_size) = s->max_packet_size;
         goto out_unlock;
     }
     if (s->max_packet_size > (*remaining_bytes)) {
         printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
                "[%zd] available\n", __func__, s->max_packet_size,
                (*remaining_bytes));
         rc = -EINVAL;
         goto out_unlock;
     }
 
     s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
     if (!s->skcipher_req) {
         printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
                "skcipher_request_alloc for %s\n", __func__,
                crypto_skcipher_driver_name(s->skcipher_tfm));
         rc = -ENOMEM;
         goto out_unlock;
     }
 
     skcipher_request_set_callback(s->skcipher_req,
                       CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
 
     s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
                         GFP_KERNEL);
     if (!s->block_aligned_filename) {
         rc = -ENOMEM;
         goto out_unlock;
     }
     dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
     rc = ecryptfs_write_packet_length(&dest[s->i],
                       (ECRYPTFS_SIG_SIZE
                        + 1 /* Cipher code */
                        + s->block_aligned_filename_size),
                       &s->packet_size_len);
     if (rc) {
         printk(KERN_ERR "%s: Error generating tag 70 packet "
                "header; cannot generate packet length; rc = [%d]\n",
                __func__, rc);
         goto out_free_unlock;
     }
     s->i += s->packet_size_len;
     ecryptfs_from_hex(&dest[s->i],
               mount_crypt_stat->global_default_fnek_sig,
               ECRYPTFS_SIG_SIZE);
     s->i += ECRYPTFS_SIG_SIZE;
     s->cipher_code = ecryptfs_code_for_cipher_string(
         mount_crypt_stat->global_default_fn_cipher_name,
         mount_crypt_stat->global_default_fn_cipher_key_bytes);
     if (s->cipher_code == 0) {
         printk(KERN_WARNING "%s: Unable to generate code for "
                "cipher [%s] with key bytes [%zd]\n", __func__,
                mount_crypt_stat->global_default_fn_cipher_name,
                mount_crypt_stat->global_default_fn_cipher_key_bytes);
         rc = -EINVAL;
         goto out_free_unlock;
     }
     dest[s->i++] = s->cipher_code;
     /* TODO: Support other key modules than passphrase for
      * filename encryption */
     if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
         rc = -EOPNOTSUPP;
         printk(KERN_INFO "%s: Filename encryption only supports "
                "password tokens\n", __func__);
         goto out_free_unlock;
     }
     s->hash_tfm = crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST, 0, 0);
     if (IS_ERR(s->hash_tfm)) {
             rc = PTR_ERR(s->hash_tfm);
             printk(KERN_ERR "%s: Error attempting to "
                    "allocate hash crypto context; rc = [%d]\n",
                    __func__, rc);
             goto out_free_unlock;
     }
 
     s->hash_desc = kmalloc(sizeof(*s->hash_desc) +
                    crypto_shash_descsize(s->hash_tfm), GFP_KERNEL);
     if (!s->hash_desc) {
         rc = -ENOMEM;
         goto out_release_free_unlock;
     }
 
     s->hash_desc->tfm = s->hash_tfm;
 
     rc = crypto_shash_digest(s->hash_desc,
                  (u8 *)s->auth_tok->token.password.session_key_encryption_key,
                  s->auth_tok->token.password.session_key_encryption_key_bytes,
                  s->hash);
     if (rc) {
         printk(KERN_ERR
                "%s: Error computing crypto hash; rc = [%d]\n",
                __func__, rc);
         goto out_release_free_unlock;
     }
     for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
         s->block_aligned_filename[s->j] =
             s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
         if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
             == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
             rc = crypto_shash_digest(s->hash_desc, (u8 *)s->hash,
                         ECRYPTFS_TAG_70_DIGEST_SIZE,
                         s->tmp_hash);
             if (rc) {
                 printk(KERN_ERR
                        "%s: Error computing crypto hash; "
                        "rc = [%d]\n", __func__, rc);
                 goto out_release_free_unlock;
             }
             memcpy(s->hash, s->tmp_hash,
                    ECRYPTFS_TAG_70_DIGEST_SIZE);
         }
         if (s->block_aligned_filename[s->j] == '\0')
             s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
     }
     memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
            filename_size);
     rc = virt_to_scatterlist(s->block_aligned_filename,
                  s->block_aligned_filename_size, s->src_sg, 2);
     if (rc < 1) {
         printk(KERN_ERR "%s: Internal error whilst attempting to "
                "convert filename memory to scatterlist; rc = [%d]. "
                "block_aligned_filename_size = [%zd]\n", __func__, rc,
                s->block_aligned_filename_size);
         goto out_release_free_unlock;
     }
     rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
                  s->dst_sg, 2);
     if (rc < 1) {
         printk(KERN_ERR "%s: Internal error whilst attempting to "
                "convert encrypted filename memory to scatterlist; "
                "rc = [%d]. block_aligned_filename_size = [%zd]\n",
                __func__, rc, s->block_aligned_filename_size);
         goto out_release_free_unlock;
     }
     /* The characters in the first block effectively do the job
      * of the IV here, so we just use 0's for the IV. Note the
      * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
      * >= ECRYPTFS_MAX_IV_BYTES. */
     rc = crypto_skcipher_setkey(
         s->skcipher_tfm,
         s->auth_tok->token.password.session_key_encryption_key,
         mount_crypt_stat->global_default_fn_cipher_key_bytes);
     if (rc < 0) {
         printk(KERN_ERR "%s: Error setting key for crypto context; "
                "rc = [%d]. s->auth_tok->token.password.session_key_"
                "encryption_key = [0x%p]; mount_crypt_stat->"
                "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
                rc,
                s->auth_tok->token.password.session_key_encryption_key,
                mount_crypt_stat->global_default_fn_cipher_key_bytes);
         goto out_release_free_unlock;
     }
     skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
                    s->block_aligned_filename_size, s->iv);
     rc = crypto_skcipher_encrypt(s->skcipher_req);
     if (rc) {
         printk(KERN_ERR "%s: Error attempting to encrypt filename; "
                "rc = [%d]\n", __func__, rc);
         goto out_release_free_unlock;
     }
     s->i += s->block_aligned_filename_size;
     (*packet_size) = s->i;
     (*remaining_bytes) -= (*packet_size);
 out_release_free_unlock:
     crypto_free_shash(s->hash_tfm);
 out_free_unlock:
     kfree_sensitive(s->block_aligned_filename);
 out_unlock:
     mutex_unlock(s->tfm_mutex);
 out:
     if (auth_tok_key) {
         up_write(&(auth_tok_key->sem));
         key_put(auth_tok_key);
     }
     skcipher_request_free(s->skcipher_req);
     kfree_sensitive(s->hash_desc);
     kfree(s);
     return rc;
 }
 
 struct ecryptfs_parse_tag_70_packet_silly_stack {
     u8 cipher_code;
     size_t max_packet_size;
     size_t packet_size_len;
     size_t parsed_tag_70_packet_size;
     size_t block_aligned_filename_size;
     size_t block_size;
     size_t i;
     struct mutex *tfm_mutex;
     char *decrypted_filename;
     struct ecryptfs_auth_tok *auth_tok;
     struct scatterlist src_sg[2];
     struct scatterlist dst_sg[2];
     struct crypto_skcipher *skcipher_tfm;
     struct skcipher_request *skcipher_req;
     char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
     char iv[ECRYPTFS_MAX_IV_BYTES];
     char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
 };
 
 /**
  * ecryptfs_parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
  * @filename: This function kmalloc's the memory for the filename
  * @filename_size: This function sets this to the amount of memory
  *                 kmalloc'd for the filename
  * @packet_size: This function sets this to the the number of octets
  *               in the packet parsed
  * @mount_crypt_stat: The mount-wide cryptographic context
  * @data: The memory location containing the start of the tag 70
  *        packet
  * @max_packet_size: The maximum legal size of the packet to be parsed
  *                   from @data
  *
  * Returns zero on success; non-zero otherwise
  */
 int
 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
                  size_t *packet_size,
                  struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
                  char *data, size_t max_packet_size)
 {
     struct ecryptfs_parse_tag_70_packet_silly_stack *s;
     struct key *auth_tok_key = NULL;
     int rc = 0;
 
     (*packet_size) = 0;
     (*filename_size) = 0;
     (*filename) = NULL;
     s = kzalloc(sizeof(*s), GFP_KERNEL);
     if (!s)
         return -ENOMEM;
 
     if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) {
         printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
                "at least [%d]\n", __func__, max_packet_size,
                ECRYPTFS_TAG_70_MIN_METADATA_SIZE);
         rc = -EINVAL;
         goto out;
     }
     /* Octet 0: Tag 70 identifier
      * Octets 1-N1: Tag 70 packet size (includes cipher identifier
      *              and block-aligned encrypted filename size)
      * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
      * Octet N2-N3: Cipher identifier (1 octet)
      * Octets N3-N4: Block-aligned encrypted filename
      *  - Consists of a minimum number of random numbers, a \0
      *    separator, and then the filename */
     if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
         printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
                "tag [0x%.2x]\n", __func__,
                data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
         rc = -EINVAL;
         goto out;
     }
     rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
                       &s->parsed_tag_70_packet_size,
                       &s->packet_size_len);
     if (rc) {
         printk(KERN_WARNING "%s: Error parsing packet length; "
                "rc = [%d]\n", __func__, rc);
         goto out;
     }
     s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
                       - ECRYPTFS_SIG_SIZE - 1);
     if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
         > max_packet_size) {
         printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
                "size is [%zd]\n", __func__, max_packet_size,
                (1 + s->packet_size_len + 1
             + s->block_aligned_filename_size));
         rc = -EINVAL;
         goto out;
     }
     (*packet_size) += s->packet_size_len;
     ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
             ECRYPTFS_SIG_SIZE);
     s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
     (*packet_size) += ECRYPTFS_SIG_SIZE;
     s->cipher_code = data[(*packet_size)++];
     rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
     if (rc) {
         printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
                __func__, s->cipher_code);
         goto out;
     }
     rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
                         &s->auth_tok, mount_crypt_stat,
                         s->fnek_sig_hex);
     if (rc) {
         printk(KERN_ERR "%s: Error attempting to find auth tok for "
                "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
                rc);
         goto out;
     }
     rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm,
                             &s->tfm_mutex,
                             s->cipher_string);
     if (unlikely(rc)) {
         printk(KERN_ERR "Internal error whilst attempting to get "
                "tfm and mutex for cipher name [%s]; rc = [%d]\n",
                s->cipher_string, rc);
         goto out;
     }
     mutex_lock(s->tfm_mutex);
     rc = virt_to_scatterlist(&data[(*packet_size)],
                  s->block_aligned_filename_size, s->src_sg, 2);
     if (rc < 1) {
         printk(KERN_ERR "%s: Internal error whilst attempting to "
                "convert encrypted filename memory to scatterlist; "
                "rc = [%d]. block_aligned_filename_size = [%zd]\n",
                __func__, rc, s->block_aligned_filename_size);
         goto out_unlock;
     }
     (*packet_size) += s->block_aligned_filename_size;
     s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
                     GFP_KERNEL);
     if (!s->decrypted_filename) {
         rc = -ENOMEM;
         goto out_unlock;
     }
     rc = virt_to_scatterlist(s->decrypted_filename,
                  s->block_aligned_filename_size, s->dst_sg, 2);
     if (rc < 1) {
         printk(KERN_ERR "%s: Internal error whilst attempting to "
                "convert decrypted filename memory to scatterlist; "
                "rc = [%d]. block_aligned_filename_size = [%zd]\n",
                __func__, rc, s->block_aligned_filename_size);
         goto out_free_unlock;
     }
 
     s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
     if (!s->skcipher_req) {
         printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
                "skcipher_request_alloc for %s\n", __func__,
                crypto_skcipher_driver_name(s->skcipher_tfm));
         rc = -ENOMEM;
         goto out_free_unlock;
     }
 
     skcipher_request_set_callback(s->skcipher_req,
                       CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
 
     /* The characters in the first block effectively do the job of
      * the IV here, so we just use 0's for the IV. Note the
      * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
      * >= ECRYPTFS_MAX_IV_BYTES. */
     /* TODO: Support other key modules than passphrase for
      * filename encryption */
     if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
         rc = -EOPNOTSUPP;
         printk(KERN_INFO "%s: Filename encryption only supports "
                "password tokens\n", __func__);
         goto out_free_unlock;
     }
     rc = crypto_skcipher_setkey(
         s->skcipher_tfm,
         s->auth_tok->token.password.session_key_encryption_key,
         mount_crypt_stat->global_default_fn_cipher_key_bytes);
     if (rc < 0) {
         printk(KERN_ERR "%s: Error setting key for crypto context; "
                "rc = [%d]. s->auth_tok->token.password.session_key_"
                "encryption_key = [0x%p]; mount_crypt_stat->"
                "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
                rc,
                s->auth_tok->token.password.session_key_encryption_key,
                mount_crypt_stat->global_default_fn_cipher_key_bytes);
         goto out_free_unlock;
     }
     skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
                    s->block_aligned_filename_size, s->iv);
     rc = crypto_skcipher_decrypt(s->skcipher_req);
     if (rc) {
         printk(KERN_ERR "%s: Error attempting to decrypt filename; "
                "rc = [%d]\n", __func__, rc);
         goto out_free_unlock;
     }
 
     while (s->i < s->block_aligned_filename_size &&
            s->decrypted_filename[s->i] != '\0')
         s->i++;
     if (s->i == s->block_aligned_filename_size) {
         printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
                "find valid separator between random characters and "
                "the filename\n", __func__);
         rc = -EINVAL;
         goto out_free_unlock;
     }
     s->i++;
     (*filename_size) = (s->block_aligned_filename_size - s->i);
     if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
         printk(KERN_WARNING "%s: Filename size is [%zd], which is "
                "invalid\n", __func__, (*filename_size));
         rc = -EINVAL;
         goto out_free_unlock;
     }
     (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
     if (!(*filename)) {
         rc = -ENOMEM;
         goto out_free_unlock;
     }
     memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
     (*filename)[(*filename_size)] = '\0';
 out_free_unlock:
     kfree(s->decrypted_filename);
 out_unlock:
     mutex_unlock(s->tfm_mutex);
 out:
     if (rc) {
         (*packet_size) = 0;
         (*filename_size) = 0;
         (*filename) = NULL;
     }
     if (auth_tok_key) {
         up_write(&(auth_tok_key->sem));
         key_put(auth_tok_key);
     }
     skcipher_request_free(s->skcipher_req);
     kfree(s);
     return rc;
 }
 
 static int
 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
 {
     int rc = 0;
 
     (*sig) = NULL;
     switch (auth_tok->token_type) {
     case ECRYPTFS_PASSWORD:
         (*sig) = auth_tok->token.password.signature;
         break;
     case ECRYPTFS_PRIVATE_KEY:
         (*sig) = auth_tok->token.private_key.signature;
         break;
     default:
         printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
                auth_tok->token_type);
         rc = -EINVAL;
     }
     return rc;
 }
 
 /**
  * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
  * @auth_tok: The key authentication token used to decrypt the session key
  * @crypt_stat: The cryptographic context
  *
  * Returns zero on success; non-zero error otherwise.
  */
 static int
 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
                   struct ecryptfs_crypt_stat *crypt_stat)
 {
     u8 cipher_code = 0;
     struct ecryptfs_msg_ctx *msg_ctx;
     struct ecryptfs_message *msg = NULL;
     char *auth_tok_sig;
     char *payload = NULL;
     size_t payload_len = 0;
     int rc;
 
     rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
     if (rc) {
         printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
                auth_tok->token_type);
         goto out;
     }
     rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
                  &payload, &payload_len);
     if (rc) {
         ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
         goto out;
     }
     rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
     if (rc) {
         ecryptfs_printk(KERN_ERR, "Error sending message to "
                 "ecryptfsd: %d\n", rc);
         goto out;
     }
     rc = ecryptfs_wait_for_response(msg_ctx, &msg);
     if (rc) {
         ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
                 "from the user space daemon\n");
         rc = -EIO;
         goto out;
     }
     rc = parse_tag_65_packet(&(auth_tok->session_key),
                  &cipher_code, msg);
     if (rc) {
         printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
                rc);
         goto out;
     }
     auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
     memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
            auth_tok->session_key.decrypted_key_size);
     crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
     rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
     if (rc) {
         ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
                 cipher_code);
         goto out;
     }
     crypt_stat->flags |= ECRYPTFS_KEY_VALID;
     if (ecryptfs_verbosity > 0) {
         ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
         ecryptfs_dump_hex(crypt_stat->key,
                   crypt_stat->key_size);
     }
 out:
     kfree(msg);
     kfree(payload);
     return rc;
 }
 
 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
 {
     struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
     struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
 
     list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
                  auth_tok_list_head, list) {
         list_del(&auth_tok_list_item->list);
         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
                 auth_tok_list_item);
     }
 }
 
 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
 
 /**
  * parse_tag_1_packet
  * @crypt_stat: The cryptographic context to modify based on packet contents
  * @data: The raw bytes of the packet.
  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
  *                 a new authentication token will be placed at the
  *                 end of this list for this packet.
  * @new_auth_tok: Pointer to a pointer to memory that this function
  *                allocates; sets the memory address of the pointer to
  *                NULL on error. This object is added to the
  *                auth_tok_list.
  * @packet_size: This function writes the size of the parsed packet
  *               into this memory location; zero on error.
  * @max_packet_size: The maximum allowable packet size
  *
  * Returns zero on success; non-zero on error.
  */
 static int
 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
            unsigned char *data, struct list_head *auth_tok_list,
            struct ecryptfs_auth_tok **new_auth_tok,
            size_t *packet_size, size_t max_packet_size)
 {
     size_t body_size;
     struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
     size_t length_size;
     int rc = 0;
 
     (*packet_size) = 0;
     (*new_auth_tok) = NULL;
     /**
      * This format is inspired by OpenPGP; see RFC 2440
      * packet tag 1
      *
      * Tag 1 identifier (1 byte)
      * Max Tag 1 packet size (max 3 bytes)
      * Version (1 byte)
      * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
      * Cipher identifier (1 byte)
      * Encrypted key size (arbitrary)
      *
      * 12 bytes minimum packet size
      */
     if (unlikely(max_packet_size < 12)) {
         printk(KERN_ERR "Invalid max packet size; must be >=12\n");
         rc = -EINVAL;
         goto out;
     }
     if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
         printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
                ECRYPTFS_TAG_1_PACKET_TYPE);
         rc = -EINVAL;
         goto out;
     }
     /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
      * at end of function upon failure */
     auth_tok_list_item =
         kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
                   GFP_KERNEL);
     if (!auth_tok_list_item) {
         printk(KERN_ERR "Unable to allocate memory\n");
         rc = -ENOMEM;
         goto out;
     }
     (*new_auth_tok) = &auth_tok_list_item->auth_tok;
     rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
                       &length_size);
     if (rc) {
         printk(KERN_WARNING "Error parsing packet length; "
                "rc = [%d]\n", rc);
         goto out_free;
     }
     if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
         printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
         rc = -EINVAL;
         goto out_free;
     }
     (*packet_size) += length_size;
     if (unlikely((*packet_size) + body_size > max_packet_size)) {
         printk(KERN_WARNING "Packet size exceeds max\n");
         rc = -EINVAL;
         goto out_free;
     }
     if (unlikely(data[(*packet_size)++] != 0x03)) {
         printk(KERN_WARNING "Unknown version number [%d]\n",
                data[(*packet_size) - 1]);
         rc = -EINVAL;
         goto out_free;
     }
     ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
             &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
     *packet_size += ECRYPTFS_SIG_SIZE;
     /* This byte is skipped because the kernel does not need to
      * know which public key encryption algorithm was used */
     (*packet_size)++;
     (*new_auth_tok)->session_key.encrypted_key_size =
         body_size - (ECRYPTFS_SIG_SIZE + 2);
     if ((*new_auth_tok)->session_key.encrypted_key_size
         > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
         printk(KERN_WARNING "Tag 1 packet contains key larger "
                "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
         rc = -EINVAL;
         goto out_free;
     }
     memcpy((*new_auth_tok)->session_key.encrypted_key,
            &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
     (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
     (*new_auth_tok)->session_key.flags &=
         ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
     (*new_auth_tok)->session_key.flags |=
         ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
     (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
     (*new_auth_tok)->flags = 0;
     (*new_auth_tok)->session_key.flags &=
         ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
     (*new_auth_tok)->session_key.flags &=
         ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
     list_add(&auth_tok_list_item->list, auth_tok_list);
     goto out;
 out_free:
     (*new_auth_tok) = NULL;
     memset(auth_tok_list_item, 0,
            sizeof(struct ecryptfs_auth_tok_list_item));
     kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
             auth_tok_list_item);
 out:
     if (rc)
         (*packet_size) = 0;
     return rc;
 }
 
 /**
  * parse_tag_3_packet
  * @crypt_stat: The cryptographic context to modify based on packet
  *              contents.
  * @data: The raw bytes of the packet.
  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
  *                 a new authentication token will be placed at the end
  *                 of this list for this packet.
  * @new_auth_tok: Pointer to a pointer to memory that this function
  *                allocates; sets the memory address of the pointer to
  *                NULL on error. This object is added to the
  *                auth_tok_list.
  * @packet_size: This function writes the size of the parsed packet
  *               into this memory location; zero on error.
  * @max_packet_size: maximum number of bytes to parse
  *
  * Returns zero on success; non-zero on error.
  */
 static int
 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
            unsigned char *data, struct list_head *auth_tok_list,
            struct ecryptfs_auth_tok **new_auth_tok,
            size_t *packet_size, size_t max_packet_size)
 {
     size_t body_size;
     struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
     size_t length_size;
     int rc = 0;
 
     (*packet_size) = 0;
     (*new_auth_tok) = NULL;
     /**
      *This format is inspired by OpenPGP; see RFC 2440
      * packet tag 3
      *
      * Tag 3 identifier (1 byte)
      * Max Tag 3 packet size (max 3 bytes)
      * Version (1 byte)
      * Cipher code (1 byte)
      * S2K specifier (1 byte)
      * Hash identifier (1 byte)
      * Salt (ECRYPTFS_SALT_SIZE)
      * Hash iterations (1 byte)
      * Encrypted key (arbitrary)
      *
      * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
      */
     if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
         printk(KERN_ERR "Max packet size too large\n");
         rc = -EINVAL;
         goto out;
     }
     if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
         printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
                ECRYPTFS_TAG_3_PACKET_TYPE);
         rc = -EINVAL;
         goto out;
     }
     /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
      * at end of function upon failure */
     auth_tok_list_item =
         kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
     if (!auth_tok_list_item) {
         printk(KERN_ERR "Unable to allocate memory\n");
         rc = -ENOMEM;
         goto out;
     }
     (*new_auth_tok) = &auth_tok_list_item->auth_tok;
     rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
                       &length_size);
     if (rc) {
         printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
                rc);
         goto out_free;
     }
     if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
         printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
         rc = -EINVAL;
         goto out_free;
     }
     (*packet_size) += length_size;
     if (unlikely((*packet_size) + body_size > max_packet_size)) {
         printk(KERN_ERR "Packet size exceeds max\n");
         rc = -EINVAL;
         goto out_free;
     }
     (*new_auth_tok)->session_key.encrypted_key_size =
         (body_size - (ECRYPTFS_SALT_SIZE + 5));
     if ((*new_auth_tok)->session_key.encrypted_key_size
         > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
         printk(KERN_WARNING "Tag 3 packet contains key larger "
                "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
         rc = -EINVAL;
         goto out_free;
     }
     if (unlikely(data[(*packet_size)++] != 0x04)) {
         printk(KERN_WARNING "Unknown version number [%d]\n",
                data[(*packet_size) - 1]);
         rc = -EINVAL;
         goto out_free;
     }
     rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
                         (u16)data[(*packet_size)]);
     if (rc)
         goto out_free;
     /* A little extra work to differentiate among the AES key
      * sizes; see RFC2440 */
     switch(data[(*packet_size)++]) {
     case RFC2440_CIPHER_AES_192:
         crypt_stat->key_size = 24;
         break;
     default:
         crypt_stat->key_size =
             (*new_auth_tok)->session_key.encrypted_key_size;
     }
     rc = ecryptfs_init_crypt_ctx(crypt_stat);
     if (rc)
         goto out_free;
     if (unlikely(data[(*packet_size)++] != 0x03)) {
         printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
         rc = -ENOSYS;
         goto out_free;
     }
     /* TODO: finish the hash mapping */
     switch (data[(*packet_size)++]) {
     case 0x01: /* See RFC2440 for these numbers and their mappings */
         /* Choose MD5 */
         memcpy((*new_auth_tok)->token.password.salt,
                &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
         (*packet_size) += ECRYPTFS_SALT_SIZE;
         /* This conversion was taken straight from RFC2440 */
         (*new_auth_tok)->token.password.hash_iterations =
             ((u32) 16 + (data[(*packet_size)] & 15))
                 << ((data[(*packet_size)] >> 4) + 6);
         (*packet_size)++;
         /* Friendly reminder:
          * (*new_auth_tok)->session_key.encrypted_key_size =
          *         (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
         memcpy((*new_auth_tok)->session_key.encrypted_key,
                &data[(*packet_size)],
                (*new_auth_tok)->session_key.encrypted_key_size);
         (*packet_size) +=
             (*new_auth_tok)->session_key.encrypted_key_size;
         (*new_auth_tok)->session_key.flags &=
             ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
         (*new_auth_tok)->session_key.flags |=
             ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
         (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
         break;
     default:
         ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
                 "[%d]\n", data[(*packet_size) - 1]);
         rc = -ENOSYS;
         goto out_free;
     }
     (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
     /* TODO: Parametarize; we might actually want userspace to
      * decrypt the session key. */
     (*new_auth_tok)->session_key.flags &=
                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
     (*new_auth_tok)->session_key.flags &=
                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
     list_add(&auth_tok_list_item->list, auth_tok_list);
     goto out;
 out_free:
     (*new_auth_tok) = NULL;
     memset(auth_tok_list_item, 0,
            sizeof(struct ecryptfs_auth_tok_list_item));
     kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
             auth_tok_list_item);
 out:
     if (rc)
         (*packet_size) = 0;
     return rc;
 }
 
 /**
  * parse_tag_11_packet
  * @data: The raw bytes of the packet
  * @contents: This function writes the data contents of the literal
  *            packet into this memory location
  * @max_contents_bytes: The maximum number of bytes that this function
  *                      is allowed to write into contents
  * @tag_11_contents_size: This function writes the size of the parsed
  *                        contents into this memory location; zero on
  *                        error
  * @packet_size: This function writes the size of the parsed packet
  *               into this memory location; zero on error
  * @max_packet_size: maximum number of bytes to parse
  *
  * Returns zero on success; non-zero on error.
  */
 static int
 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
             size_t max_contents_bytes, size_t *tag_11_contents_size,
             size_t *packet_size, size_t max_packet_size)
 {
     size_t body_size;
     size_t length_size;
     int rc = 0;
 
     (*packet_size) = 0;
     (*tag_11_contents_size) = 0;
     /* This format is inspired by OpenPGP; see RFC 2440
      * packet tag 11
      *
      * Tag 11 identifier (1 byte)
      * Max Tag 11 packet size (max 3 bytes)
      * Binary format specifier (1 byte)
      * Filename length (1 byte)
      * Filename ("_CONSOLE") (8 bytes)
      * Modification date (4 bytes)
      * Literal data (arbitrary)
      *
      * We need at least 16 bytes of data for the packet to even be
      * valid.
      */
     if (max_packet_size < 16) {
         printk(KERN_ERR "Maximum packet size too small\n");
         rc = -EINVAL;
         goto out;
     }
     if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
         printk(KERN_WARNING "Invalid tag 11 packet format\n");
         rc = -EINVAL;
         goto out;
     }
     rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
                       &length_size);
     if (rc) {
         printk(KERN_WARNING "Invalid tag 11 packet format\n");
         goto out;
     }
     if (body_size < 14) {
         printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
         rc = -EINVAL;
         goto out;
     }
     (*packet_size) += length_size;
     (*tag_11_contents_size) = (body_size - 14);
     if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
         printk(KERN_ERR "Packet size exceeds max\n");
         rc = -EINVAL;
         goto out;
     }
     if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
         printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
                "expected size\n");
         rc = -EINVAL;
         goto out;
     }
     if (data[(*packet_size)++] != 0x62) {
         printk(KERN_WARNING "Unrecognizable packet\n");
         rc = -EINVAL;
         goto out;
     }
     if (data[(*packet_size)++] != 0x08) {
         printk(KERN_WARNING "Unrecognizable packet\n");
         rc = -EINVAL;
         goto out;
     }
     (*packet_size) += 12; /* Ignore filename and modification date */
     memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
     (*packet_size) += (*tag_11_contents_size);
 out:
     if (rc) {
         (*packet_size) = 0;
         (*tag_11_contents_size) = 0;
     }
     return rc;
 }
 
 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
                       struct ecryptfs_auth_tok **auth_tok,
                       char *sig)
 {
     int rc = 0;
 
     (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
     if (IS_ERR(*auth_tok_key)) {
         (*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
         if (IS_ERR(*auth_tok_key)) {
             printk(KERN_ERR "Could not find key with description: [%s]\n",
                   sig);
             rc = process_request_key_err(PTR_ERR(*auth_tok_key));
             (*auth_tok_key) = NULL;
             goto out;
         }
     }
     down_write(&(*auth_tok_key)->sem);
     rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
     if (rc) {
         up_write(&(*auth_tok_key)->sem);
         key_put(*auth_tok_key);
         (*auth_tok_key) = NULL;
         goto out;
     }
 out:
     return rc;
 }
 
 /**
  * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
  * @auth_tok: The passphrase authentication token to use to encrypt the FEK
  * @crypt_stat: The cryptographic context
  *
  * Returns zero on success; non-zero error otherwise
  */
 static int
 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
                      struct ecryptfs_crypt_stat *crypt_stat)
 {
     struct scatterlist dst_sg[2];
     struct scatterlist src_sg[2];
     struct mutex *tfm_mutex;
     struct crypto_skcipher *tfm;
     struct skcipher_request *req = NULL;
     int rc = 0;
 
     if (unlikely(ecryptfs_verbosity > 0)) {
         ecryptfs_printk(
             KERN_DEBUG, "Session key encryption key (size [%d]):\n",
             auth_tok->token.password.session_key_encryption_key_bytes);
         ecryptfs_dump_hex(
             auth_tok->token.password.session_key_encryption_key,
             auth_tok->token.password.session_key_encryption_key_bytes);
     }
     rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
                             crypt_stat->cipher);
     if (unlikely(rc)) {
         printk(KERN_ERR "Internal error whilst attempting to get "
                "tfm and mutex for cipher name [%s]; rc = [%d]\n",
                crypt_stat->cipher, rc);
         goto out;
     }
     rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
                  auth_tok->session_key.encrypted_key_size,
                  src_sg, 2);
     if (rc < 1 || rc > 2) {
         printk(KERN_ERR "Internal error whilst attempting to convert "
             "auth_tok->session_key.encrypted_key to scatterlist; "
             "expected rc = 1; got rc = [%d]. "
                "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
             auth_tok->session_key.encrypted_key_size);
         goto out;
     }
     auth_tok->session_key.decrypted_key_size =
         auth_tok->session_key.encrypted_key_size;
     rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
                  auth_tok->session_key.decrypted_key_size,
                  dst_sg, 2);
     if (rc < 1 || rc > 2) {
         printk(KERN_ERR "Internal error whilst attempting to convert "
             "auth_tok->session_key.decrypted_key to scatterlist; "
             "expected rc = 1; got rc = [%d]\n", rc);
         goto out;
     }
     mutex_lock(tfm_mutex);
     req = skcipher_request_alloc(tfm, GFP_KERNEL);
     if (!req) {
         mutex_unlock(tfm_mutex);
         printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
                "skcipher_request_alloc for %s\n", __func__,
                crypto_skcipher_driver_name(tfm));
         rc = -ENOMEM;
         goto out;
     }
 
     skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
                       NULL, NULL);
     rc = crypto_skcipher_setkey(
         tfm, auth_tok->token.password.session_key_encryption_key,
         crypt_stat->key_size);
     if (unlikely(rc < 0)) {
         mutex_unlock(tfm_mutex);
         printk(KERN_ERR "Error setting key for crypto context\n");
         rc = -EINVAL;
         goto out;
     }
     skcipher_request_set_crypt(req, src_sg, dst_sg,
                    auth_tok->session_key.encrypted_key_size,
                    NULL);
     rc = crypto_skcipher_decrypt(req);
     mutex_unlock(tfm_mutex);
     if (unlikely(rc)) {
         printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
         goto out;
     }
     auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
     memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
            auth_tok->session_key.decrypted_key_size);
     crypt_stat->flags |= ECRYPTFS_KEY_VALID;
     if (unlikely(ecryptfs_verbosity > 0)) {
         ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
                 crypt_stat->key_size);
         ecryptfs_dump_hex(crypt_stat->key,
                   crypt_stat->key_size);
     }
 out:
     skcipher_request_free(req);
     return rc;
 }
 
 /**
  * ecryptfs_parse_packet_set
  * @crypt_stat: The cryptographic context
  * @src: Virtual address of region of memory containing the packets
  * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
  *
  * Get crypt_stat to have the file's session key if the requisite key
  * is available to decrypt the session key.
  *
  * Returns Zero if a valid authentication token was retrieved and
  * processed; negative value for file not encrypted or for error
  * conditions.
  */
 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
                   unsigned char *src,
                   struct dentry *ecryptfs_dentry)
 {
     size_t i = 0;
     size_t found_auth_tok;
     size_t next_packet_is_auth_tok_packet;
     struct list_head auth_tok_list;
     struct ecryptfs_auth_tok *matching_auth_tok;
     struct ecryptfs_auth_tok *candidate_auth_tok;
     char *candidate_auth_tok_sig;
     size_t packet_size;
     struct ecryptfs_auth_tok *new_auth_tok;
     unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
     struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
     size_t tag_11_contents_size;
     size_t tag_11_packet_size;
     struct key *auth_tok_key = NULL;
     int rc = 0;
 
     INIT_LIST_HEAD(&auth_tok_list);
     /* Parse the header to find as many packets as we can; these will be
      * added the our &auth_tok_list */
     next_packet_is_auth_tok_packet = 1;
     while (next_packet_is_auth_tok_packet) {
         size_t max_packet_size = ((PAGE_SIZE - 8) - i);
 
         switch (src[i]) {
         case ECRYPTFS_TAG_3_PACKET_TYPE:
             rc = parse_tag_3_packet(crypt_stat,
                         (unsigned char *)&src[i],
                         &auth_tok_list, &new_auth_tok,
                         &packet_size, max_packet_size);
             if (rc) {
                 ecryptfs_printk(KERN_ERR, "Error parsing "
                         "tag 3 packet\n");
                 rc = -EIO;
                 goto out_wipe_list;
             }
             i += packet_size;
             rc = parse_tag_11_packet((unsigned char *)&src[i],
                          sig_tmp_space,
                          ECRYPTFS_SIG_SIZE,
                          &tag_11_contents_size,
                          &tag_11_packet_size,
                          max_packet_size);
             if (rc) {
                 ecryptfs_printk(KERN_ERR, "No valid "
                         "(ecryptfs-specific) literal "
                         "packet containing "
                         "authentication token "
                         "signature found after "
                         "tag 3 packet\n");
                 rc = -EIO;
                 goto out_wipe_list;
             }
             i += tag_11_packet_size;
             if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
                 ecryptfs_printk(KERN_ERR, "Expected "
                         "signature of size [%d]; "
                         "read size [%zd]\n",
                         ECRYPTFS_SIG_SIZE,
                         tag_11_contents_size);
                 rc = -EIO;
                 goto out_wipe_list;
             }
             ecryptfs_to_hex(new_auth_tok->token.password.signature,
                     sig_tmp_space, tag_11_contents_size);
             new_auth_tok->token.password.signature[
                 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
             crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
             break;
         case ECRYPTFS_TAG_1_PACKET_TYPE:
             rc = parse_tag_1_packet(crypt_stat,
                         (unsigned char *)&src[i],
                         &auth_tok_list, &new_auth_tok,
                         &packet_size, max_packet_size);
             if (rc) {
                 ecryptfs_printk(KERN_ERR, "Error parsing "
                         "tag 1 packet\n");
                 rc = -EIO;
                 goto out_wipe_list;
             }
             i += packet_size;
             crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
             break;
         case ECRYPTFS_TAG_11_PACKET_TYPE:
             ecryptfs_printk(KERN_WARNING, "Invalid packet set "
                     "(Tag 11 not allowed by itself)\n");
             rc = -EIO;
             goto out_wipe_list;
         default:
             ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
                     "of the file header; hex value of "
                     "character is [0x%.2x]\n", i, src[i]);
             next_packet_is_auth_tok_packet = 0;
         }
     }
     if (list_empty(&auth_tok_list)) {
         printk(KERN_ERR "The lower file appears to be a non-encrypted "
                "eCryptfs file; this is not supported in this version "
                "of the eCryptfs kernel module\n");
         rc = -EINVAL;
         goto out;
     }
     /* auth_tok_list contains the set of authentication tokens
      * parsed from the metadata. We need to find a matching
      * authentication token that has the secret component(s)
      * necessary to decrypt the EFEK in the auth_tok parsed from
      * the metadata. There may be several potential matches, but
      * just one will be sufficient to decrypt to get the FEK. */
 find_next_matching_auth_tok:
     found_auth_tok = 0;
     list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
         candidate_auth_tok = &auth_tok_list_item->auth_tok;
         if (unlikely(ecryptfs_verbosity > 0)) {
             ecryptfs_printk(KERN_DEBUG,
                     "Considering candidate auth tok:\n");
             ecryptfs_dump_auth_tok(candidate_auth_tok);
         }
         rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
                            candidate_auth_tok);
         if (rc) {
             printk(KERN_ERR
                    "Unrecognized candidate auth tok type: [%d]\n",
                    candidate_auth_tok->token_type);
             rc = -EINVAL;
             goto out_wipe_list;
         }
         rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
                            &matching_auth_tok,
                            crypt_stat->mount_crypt_stat,
                            candidate_auth_tok_sig);
         if (!rc) {
             found_auth_tok = 1;
             goto found_matching_auth_tok;
         }
     }
     if (!found_auth_tok) {
         ecryptfs_printk(KERN_ERR, "Could not find a usable "
                 "authentication token\n");
         rc = -EIO;
         goto out_wipe_list;
     }
 found_matching_auth_tok:
     if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
         memcpy(&(candidate_auth_tok->token.private_key),
                &(matching_auth_tok->token.private_key),
                sizeof(struct ecryptfs_private_key));
         up_write(&(auth_tok_key->sem));
         key_put(auth_tok_key);
         rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
                                crypt_stat);
     } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
         memcpy(&(candidate_auth_tok->token.password),
                &(matching_auth_tok->token.password),
                sizeof(struct ecryptfs_password));
         up_write(&(auth_tok_key->sem));
         key_put(auth_tok_key);
         rc = decrypt_passphrase_encrypted_session_key(
             candidate_auth_tok, crypt_stat);
     } else {
         up_write(&(auth_tok_key->sem));
         key_put(auth_tok_key);
         rc = -EINVAL;
     }
     if (rc) {
         struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
 
         ecryptfs_printk(KERN_WARNING, "Error decrypting the "
                 "session key for authentication token with sig "
                 "[%.*s]; rc = [%d]. Removing auth tok "
                 "candidate from the list and searching for "
                 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
                 candidate_auth_tok_sig, rc);
         list_for_each_entry_safe(auth_tok_list_item,
                      auth_tok_list_item_tmp,
                      &auth_tok_list, list) {
             if (candidate_auth_tok
                 == &auth_tok_list_item->auth_tok) {
                 list_del(&auth_tok_list_item->list);
                 kmem_cache_free(
                     ecryptfs_auth_tok_list_item_cache,
                     auth_tok_list_item);
                 goto find_next_matching_auth_tok;
             }
         }
         BUG();
     }
     rc = ecryptfs_compute_root_iv(crypt_stat);
     if (rc) {
         ecryptfs_printk(KERN_ERR, "Error computing "
                 "the root IV\n");
         goto out_wipe_list;
     }
     rc = ecryptfs_init_crypt_ctx(crypt_stat);
     if (rc) {
         ecryptfs_printk(KERN_ERR, "Error initializing crypto "
                 "context for cipher [%s]; rc = [%d]\n",
                 crypt_stat->cipher, rc);
     }
 out_wipe_list:
     wipe_auth_tok_list(&auth_tok_list);
 out:
     return rc;
 }
 
 static int
 pki_encrypt_session_key(struct key *auth_tok_key,
             struct ecryptfs_auth_tok *auth_tok,
             struct ecryptfs_crypt_stat *crypt_stat,
             struct ecryptfs_key_record *key_rec)
 {
     struct ecryptfs_msg_ctx *msg_ctx = NULL;
     char *payload = NULL;
     size_t payload_len = 0;
     struct ecryptfs_message *msg;
     int rc;
 
     rc = write_tag_66_packet(auth_tok->token.private_key.signature,
                  ecryptfs_code_for_cipher_string(
                      crypt_stat->cipher,
                      crypt_stat->key_size),
                  crypt_stat, &payload, &payload_len);
     up_write(&(auth_tok_key->sem));
     key_put(auth_tok_key);
     if (rc) {
         ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
         goto out;
     }
     rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
     if (rc) {
         ecryptfs_printk(KERN_ERR, "Error sending message to "
                 "ecryptfsd: %d\n", rc);
         goto out;
     }
     rc = ecryptfs_wait_for_response(msg_ctx, &msg);
     if (rc) {
         ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
                 "from the user space daemon\n");
         rc = -EIO;
         goto out;
     }
     rc = parse_tag_67_packet(key_rec, msg);
     if (rc)
         ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
     kfree(msg);
 out:
     kfree(payload);
     return rc;
 }
 /**
  * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
  * @dest: Buffer into which to write the packet
  * @remaining_bytes: Maximum number of bytes that can be writtn
  * @auth_tok_key: The authentication token key to unlock and put when done with
  *                @auth_tok
  * @auth_tok: The authentication token used for generating the tag 1 packet
  * @crypt_stat: The cryptographic context
  * @key_rec: The key record struct for the tag 1 packet
  * @packet_size: This function will write the number of bytes that end
  *               up constituting the packet; set to zero on error
  *
  * Returns zero on success; non-zero on error.
  */
 static int
 write_tag_1_packet(char *dest, size_t *remaining_bytes,
            struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
            struct ecryptfs_crypt_stat *crypt_stat,
            struct ecryptfs_key_record *key_rec, size_t *packet_size)
 {
     size_t i;
     size_t encrypted_session_key_valid = 0;
     size_t packet_size_length;
     size_t max_packet_size;
     int rc = 0;
 
     (*packet_size) = 0;
     ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
               ECRYPTFS_SIG_SIZE);
     encrypted_session_key_valid = 0;
     for (i = 0; i < crypt_stat->key_size; i++)
         encrypted_session_key_valid |=
             auth_tok->session_key.encrypted_key[i];
     if (encrypted_session_key_valid) {
         memcpy(key_rec->enc_key,
                auth_tok->session_key.encrypted_key,
                auth_tok->session_key.encrypted_key_size);
         up_write(&(auth_tok_key->sem));
         key_put(auth_tok_key);
         goto encrypted_session_key_set;
     }
     if (auth_tok->session_key.encrypted_key_size == 0)
         auth_tok->session_key.encrypted_key_size =
             auth_tok->token.private_key.key_size;
     rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
                      key_rec);
     if (rc) {
         printk(KERN_ERR "Failed to encrypt session key via a key "
                "module; rc = [%d]\n", rc);
         goto out;
     }
     if (ecryptfs_verbosity > 0) {
         ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
         ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
     }
 encrypted_session_key_set:
     /* This format is inspired by OpenPGP; see RFC 2440
      * packet tag 1 */
     max_packet_size = (1                         /* Tag 1 identifier */
                + 3                       /* Max Tag 1 packet size */
                + 1                       /* Version */
                + ECRYPTFS_SIG_SIZE       /* Key identifier */
                + 1                       /* Cipher identifier */
                + key_rec->enc_key_size); /* Encrypted key size */
     if (max_packet_size > (*remaining_bytes)) {
         printk(KERN_ERR "Packet length larger than maximum allowable; "
                "need up to [%td] bytes, but there are only [%td] "
                "available\n", max_packet_size, (*remaining_bytes));
         rc = -EINVAL;
         goto out;
     }
     dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
     rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
                       (max_packet_size - 4),
                       &packet_size_length);
     if (rc) {
         ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
                 "header; cannot generate packet length\n");
         goto out;
     }
     (*packet_size) += packet_size_length;
     dest[(*packet_size)++] = 0x03; /* version 3 */
     memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
     (*packet_size) += ECRYPTFS_SIG_SIZE;
     dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
     memcpy(&dest[(*packet_size)], key_rec->enc_key,
            key_rec->enc_key_size);
     (*packet_size) += key_rec->enc_key_size;
 out:
     if (rc)
         (*packet_size) = 0;
     else
         (*remaining_bytes) -= (*packet_size);
     return rc;
 }
 
 /**
  * write_tag_11_packet
  * @dest: Target into which Tag 11 packet is to be written
  * @remaining_bytes: Maximum packet length
  * @contents: Byte array of contents to copy in
  * @contents_length: Number of bytes in contents
  * @packet_length: Length of the Tag 11 packet written; zero on error
  *
  * Returns zero on success; non-zero on error.
  */
 static int
 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
             size_t contents_length, size_t *packet_length)
 {
     size_t packet_size_length;
     size_t max_packet_size;
     int rc = 0;
 
     (*packet_length) = 0;
     /* This format is inspired by OpenPGP; see RFC 2440
      * packet tag 11 */
     max_packet_size = (1                   /* Tag 11 identifier */
                + 3                 /* Max Tag 11 packet size */
                + 1                 /* Binary format specifier */
                + 1                 /* Filename length */
                + 8                 /* Filename ("_CONSOLE") */
                + 4                 /* Modification date */
                + contents_length); /* Literal data */
     if (max_packet_size > (*remaining_bytes)) {
         printk(KERN_ERR "Packet length larger than maximum allowable; "
                "need up to [%td] bytes, but there are only [%td] "
                "available\n", max_packet_size, (*remaining_bytes));
         rc = -EINVAL;
         goto out;
     }
     dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
     rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
                       (max_packet_size - 4),
                       &packet_size_length);
     if (rc) {
         printk(KERN_ERR "Error generating tag 11 packet header; cannot "
                "generate packet length. rc = [%d]\n", rc);
         goto out;
     }
     (*packet_length) += packet_size_length;
     dest[(*packet_length)++] = 0x62; /* binary data format specifier */
     dest[(*packet_length)++] = 8;
     memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
     (*packet_length) += 8;
     memset(&dest[(*packet_length)], 0x00, 4);
     (*packet_length) += 4;
     memcpy(&dest[(*packet_length)], contents, contents_length);
     (*packet_length) += contents_length;
  out:
     if (rc)
         (*packet_length) = 0;
     else
         (*remaining_bytes) -= (*packet_length);
     return rc;
 }
 
 /**
  * write_tag_3_packet
  * @dest: Buffer into which to write the packet
  * @remaining_bytes: Maximum number of bytes that can be written
  * @auth_tok: Authentication token
  * @crypt_stat: The cryptographic context
  * @key_rec: encrypted key
  * @packet_size: This function will write the number of bytes that end
  *               up constituting the packet; set to zero on error
  *
  * Returns zero on success; non-zero on error.
  */
 static int
 write_tag_3_packet(char *dest, size_t *remaining_bytes,
            struct ecryptfs_auth_tok *auth_tok,
            struct ecryptfs_crypt_stat *crypt_stat,
            struct ecryptfs_key_record *key_rec, size_t *packet_size)
 {
     size_t i;
     size_t encrypted_session_key_valid = 0;
     char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
     struct scatterlist dst_sg[2];
     struct scatterlist src_sg[2];
     struct mutex *tfm_mutex = NULL;
     u8 cipher_code;
     size_t packet_size_length;
     size_t max_packet_size;
     struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
         crypt_stat->mount_crypt_stat;
     struct crypto_skcipher *tfm;
     struct skcipher_request *req;
     int rc = 0;
 
     (*packet_size) = 0;
     ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
               ECRYPTFS_SIG_SIZE);
     rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
                             crypt_stat->cipher);
     if (unlikely(rc)) {
         printk(KERN_ERR "Internal error whilst attempting to get "
                "tfm and mutex for cipher name [%s]; rc = [%d]\n",
                crypt_stat->cipher, rc);
         goto out;
     }
     if (mount_crypt_stat->global_default_cipher_key_size == 0) {
         printk(KERN_WARNING "No key size specified at mount; "
                "defaulting to [%d]\n",
                crypto_skcipher_max_keysize(tfm));
         mount_crypt_stat->global_default_cipher_key_size =
             crypto_skcipher_max_keysize(tfm);
     }
     if (crypt_stat->key_size == 0)
         crypt_stat->key_size =
             mount_crypt_stat->global_default_cipher_key_size;
     if (auth_tok->session_key.encrypted_key_size == 0)
         auth_tok->session_key.encrypted_key_size =
             crypt_stat->key_size;
     if (crypt_stat->key_size == 24
         && strcmp("aes", crypt_stat->cipher) == 0) {
         memset((crypt_stat->key + 24), 0, 8);
         auth_tok->session_key.encrypted_key_size = 32;
     } else
         auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
     key_rec->enc_key_size =
         auth_tok->session_key.encrypted_key_size;
     encrypted_session_key_valid = 0;
     for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
         encrypted_session_key_valid |=
             auth_tok->session_key.encrypted_key[i];
     if (encrypted_session_key_valid) {
         ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
                 "using auth_tok->session_key.encrypted_key, "
                 "where key_rec->enc_key_size = [%zd]\n",
                 key_rec->enc_key_size);
         memcpy(key_rec->enc_key,
                auth_tok->session_key.encrypted_key,
                key_rec->enc_key_size);
         goto encrypted_session_key_set;
     }
     if (auth_tok->token.password.flags &
         ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
         ecryptfs_printk(KERN_DEBUG, "Using previously generated "
                 "session key encryption key of size [%d]\n",
                 auth_tok->token.password.
                 session_key_encryption_key_bytes);
         memcpy(session_key_encryption_key,
                auth_tok->token.password.session_key_encryption_key,
                crypt_stat->key_size);
         ecryptfs_printk(KERN_DEBUG,
                 "Cached session key encryption key:\n");
         if (ecryptfs_verbosity > 0)
             ecryptfs_dump_hex(session_key_encryption_key, 16);
     }
     if (unlikely(ecryptfs_verbosity > 0)) {
         ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
         ecryptfs_dump_hex(session_key_encryption_key, 16);
     }
     rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
                  src_sg, 2);
     if (rc < 1 || rc > 2) {
         ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
                 "for crypt_stat session key; expected rc = 1; "
                 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
                 rc, key_rec->enc_key_size);
         rc = -ENOMEM;
         goto out;
     }
     rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
                  dst_sg, 2);
     if (rc < 1 || rc > 2) {
         ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
                 "for crypt_stat encrypted session key; "
                 "expected rc = 1; got rc = [%d]. "
                 "key_rec->enc_key_size = [%zd]\n", rc,
                 key_rec->enc_key_size);
         rc = -ENOMEM;
         goto out;
     }
     mutex_lock(tfm_mutex);
     rc = crypto_skcipher_setkey(tfm, session_key_encryption_key,
                     crypt_stat->key_size);
     if (rc < 0) {
         mutex_unlock(tfm_mutex);
         ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
                 "context; rc = [%d]\n", rc);
         goto out;
     }
 
     req = skcipher_request_alloc(tfm, GFP_KERNEL);
     if (!req) {
         mutex_unlock(tfm_mutex);
         ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst "
                 "attempting to skcipher_request_alloc for "
                 "%s\n", crypto_skcipher_driver_name(tfm));
         rc = -ENOMEM;
         goto out;
     }
 
     skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
                       NULL, NULL);
 
     rc = 0;
     ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
             crypt_stat->key_size);
     skcipher_request_set_crypt(req, src_sg, dst_sg,
                    (*key_rec).enc_key_size, NULL);
     rc = crypto_skcipher_encrypt(req);
     mutex_unlock(tfm_mutex);
     skcipher_request_free(req);
     if (rc) {
         printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
         goto out;
     }
     ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
     if (ecryptfs_verbosity > 0) {
         ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
                 key_rec->enc_key_size);
         ecryptfs_dump_hex(key_rec->enc_key,
                   key_rec->enc_key_size);
     }
 encrypted_session_key_set:
     /* This format is inspired by OpenPGP; see RFC 2440
      * packet tag 3 */
     max_packet_size = (1                         /* Tag 3 identifier */
                + 3                       /* Max Tag 3 packet size */
                + 1                       /* Version */
                + 1                       /* Cipher code */
                + 1                       /* S2K specifier */
                + 1                       /* Hash identifier */
                + ECRYPTFS_SALT_SIZE      /* Salt */
                + 1                       /* Hash iterations */
                + key_rec->enc_key_size); /* Encrypted key size */
     if (max_packet_size > (*remaining_bytes)) {
         printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
                "there are only [%td] available\n", max_packet_size,
                (*remaining_bytes));
         rc = -EINVAL;
         goto out;
     }
     dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
     /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
      * to get the number of octets in the actual Tag 3 packet */
     rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
                       (max_packet_size - 4),
                       &packet_size_length);
     if (rc) {
         printk(KERN_ERR "Error generating tag 3 packet header; cannot "
                "generate packet length. rc = [%d]\n", rc);
         goto out;
     }
     (*packet_size) += packet_size_length;
     dest[(*packet_size)++] = 0x04; /* version 4 */
     /* TODO: Break from RFC2440 so that arbitrary ciphers can be
      * specified with strings */
     cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
                               crypt_stat->key_size);
     if (cipher_code == 0) {
         ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
                 "cipher [%s]\n", crypt_stat->cipher);
         rc = -EINVAL;
         goto out;
     }
     dest[(*packet_size)++] = cipher_code;
     dest[(*packet_size)++] = 0x03;  /* S2K */
     dest[(*packet_size)++] = 0x01;  /* MD5 (TODO: parameterize) */
     memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
            ECRYPTFS_SALT_SIZE);
     (*packet_size) += ECRYPTFS_SALT_SIZE;   /* salt */
     dest[(*packet_size)++] = 0x60;  /* hash iterations (65536) */
     memcpy(&dest[(*packet_size)], key_rec->enc_key,
            key_rec->enc_key_size);
     (*packet_size) += key_rec->enc_key_size;
 out:
     if (rc)
         (*packet_size) = 0;
     else
         (*remaining_bytes) -= (*packet_size);
     return rc;
 }
 
 struct kmem_cache *ecryptfs_key_record_cache;
 
 /**
  * ecryptfs_generate_key_packet_set
  * @dest_base: Virtual address from which to write the key record set
  * @crypt_stat: The cryptographic context from which the
  *              authentication tokens will be retrieved
  * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
  *                   for the global parameters
  * @len: The amount written
  * @max: The maximum amount of data allowed to be written
  *
  * Generates a key packet set and writes it to the virtual address
  * passed in.
  *
  * Returns zero on success; non-zero on error.
  */
 int
 ecryptfs_generate_key_packet_set(char *dest_base,
                  struct ecryptfs_crypt_stat *crypt_stat,
                  struct dentry *ecryptfs_dentry, size_t *len,
                  size_t max)
 {
     struct ecryptfs_auth_tok *auth_tok;
     struct key *auth_tok_key = NULL;
     struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
         &ecryptfs_superblock_to_private(
             ecryptfs_dentry->d_sb)->mount_crypt_stat;
     size_t written;
     struct ecryptfs_key_record *key_rec;
     struct ecryptfs_key_sig *key_sig;
     int rc = 0;
 
     (*len) = 0;
     mutex_lock(&crypt_stat->keysig_list_mutex);
     key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
     if (!key_rec) {
         rc = -ENOMEM;
         goto out;
     }
     list_for_each_entry(key_sig, &crypt_stat->keysig_list,
                 crypt_stat_list) {
         memset(key_rec, 0, sizeof(*key_rec));
         rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
                                &auth_tok,
                                mount_crypt_stat,
                                key_sig->keysig);
         if (rc) {
             printk(KERN_WARNING "Unable to retrieve auth tok with "
                    "sig = [%s]\n", key_sig->keysig);
             rc = process_find_global_auth_tok_for_sig_err(rc);
             goto out_free;
         }
         if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
             rc = write_tag_3_packet((dest_base + (*len)),
                         &max, auth_tok,
                         crypt_stat, key_rec,
                         &written);
             up_write(&(auth_tok_key->sem));
             key_put(auth_tok_key);
             if (rc) {
                 ecryptfs_printk(KERN_WARNING, "Error "
                         "writing tag 3 packet\n");
                 goto out_free;
             }
             (*len) += written;
             /* Write auth tok signature packet */
             rc = write_tag_11_packet((dest_base + (*len)), &max,
                          key_rec->sig,
                          ECRYPTFS_SIG_SIZE, &written);
             if (rc) {
                 ecryptfs_printk(KERN_ERR, "Error writing "
                         "auth tok signature packet\n");
                 goto out_free;
             }
             (*len) += written;
         } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
             rc = write_tag_1_packet(dest_base + (*len), &max,
                         auth_tok_key, auth_tok,
                         crypt_stat, key_rec, &written);
             if (rc) {
                 ecryptfs_printk(KERN_WARNING, "Error "
                         "writing tag 1 packet\n");
                 goto out_free;
             }
             (*len) += written;
         } else {
             up_write(&(auth_tok_key->sem));
             key_put(auth_tok_key);
             ecryptfs_printk(KERN_WARNING, "Unsupported "
                     "authentication token type\n");
             rc = -EINVAL;
             goto out_free;
         }
     }
     if (likely(max > 0)) {
         dest_base[(*len)] = 0x00;
     } else {
         ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
         rc = -EIO;
     }
 out_free:
     kmem_cache_free(ecryptfs_key_record_cache, key_rec);
 out:
     if (rc)
         (*len) = 0;
     mutex_unlock(&crypt_stat->keysig_list_mutex);
     return rc;
 }
 
 struct kmem_cache *ecryptfs_key_sig_cache;
 
 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
 {
     struct ecryptfs_key_sig *new_key_sig;
 
     new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
     if (!new_key_sig)
         return -ENOMEM;
 
     memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
     new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
     /* Caller must hold keysig_list_mutex */
     list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
 
     return 0;
 }
 
 struct kmem_cache *ecryptfs_global_auth_tok_cache;
 
 int
 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
                  char *sig, u32 global_auth_tok_flags)
 {
     struct ecryptfs_global_auth_tok *new_auth_tok;
 
     new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
                     GFP_KERNEL);
     if (!new_auth_tok)
         return -ENOMEM;
 
     memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
     new_auth_tok->flags = global_auth_tok_flags;
     new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
     mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
     list_add(&new_auth_tok->mount_crypt_stat_list,
          &mount_crypt_stat->global_auth_tok_list);
     mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
     return 0;
 }
 

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