Re: [PATCH 1/8] eCryptfs: Add key list structure; search keyring

[Serge E. Hallyn]

Quoting Michael Halcrow (mhalcrow@xxxxxxxxxx):
> Add support structures for handling multiple keys. The list in

Excellent.

Very glad to see this implemented.  A few comments inline.

> crypt_stat contains the key identifiers for all of the keys that
> should be used for encrypting each file's File Encryption Key
> (FEK). For now, each inode inherits this list from the mount-wide
> crypt_stat struct, via the
> ecryptfs_copy_mount_wide_sigs_to_inode_sigs() function.
> 
> This patch also removes the global key tfm from the mount-wide
> crypt_stat struct, instead keeping a list of tfm's meant for dealing
> with the various inode FEK's. eCryptfs will now search the user's
> keyring for FEK's parsed from the existing file metadata, so the user
> can make keys available at any time before or after mounting.
> 
> Now that multiple FEK packets can be written to the file metadata, we
> need to be more meticulous about size limits. The updates to the code
> for writing out packets to the file metadata makes sizes and limits
> more explicit, uniformly expressed, and (hopefully) easier to follow.
> 
> Signed-off-by: Michael Halcrow <mhalcrow@xxxxxxxxxx>
> ---
>  fs/ecryptfs/crypto.c          |  208 ++++++++++--
>  fs/ecryptfs/ecryptfs_kernel.h |   71 ++++-
>  fs/ecryptfs/keystore.c        |  743 ++++++++++++++++++++++++++---------------
>  fs/ecryptfs/main.c            |  121 +++-----
>  4 files changed, 742 insertions(+), 401 deletions(-)
> 
> diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
> index 6ac6306..4f7d895 100644
> --- a/fs/ecryptfs/crypto.c
> +++ b/fs/ecryptfs/crypto.c
> @@ -204,6 +204,8 @@ void
>  ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
>  {
>  	memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
> +	INIT_LIST_HEAD(&crypt_stat->keysig_list);
> +	mutex_init(&crypt_stat->keysig_list_mutex);
>  	mutex_init(&crypt_stat->cs_mutex);
>  	mutex_init(&crypt_stat->cs_tfm_mutex);
>  	mutex_init(&crypt_stat->cs_hash_tfm_mutex);
> @@ -218,20 +220,41 @@ ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
>   */
>  void ecryptfs_destruct_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
>  {
> +	struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
> +
>  	if (crypt_stat->tfm)
>  		crypto_free_blkcipher(crypt_stat->tfm);
>  	if (crypt_stat->hash_tfm)
>  		crypto_free_hash(crypt_stat->hash_tfm);
> +	mutex_lock(&crypt_stat->keysig_list_mutex);

Curious - at this point you know you have the last reference to
the inode, right?  And you're not decrementing a use count on the
crypt_stats, you're just zeroing it out.  So you must not think anyone
else has references to it.

So why do you need to grab the mutex here?

> +	list_for_each_entry_safe(key_sig, key_sig_tmp,
> +				 &crypt_stat->keysig_list, crypt_stat_list) {
> +		list_del(&key_sig->crypt_stat_list);
> +		kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
> +	}
> +	mutex_unlock(&crypt_stat->keysig_list_mutex);
>  	memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
>  }
>  
>  void ecryptfs_destruct_mount_crypt_stat(
>  	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
>  {
> -	if (mount_crypt_stat->global_auth_tok_key)
> -		key_put(mount_crypt_stat->global_auth_tok_key);
> -	if (mount_crypt_stat->global_key_tfm)
> -		crypto_free_blkcipher(mount_crypt_stat->global_key_tfm);
> +	struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
> +
> +	if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
> +		return;
> +	mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);

Same question here - after all it's called from put_super...  So if
not having the mutex cause the problem doesn't that mean the mutex
is papering over some other problem?

> +	list_for_each_entry_safe(auth_tok, auth_tok_tmp,
> +				 &mount_crypt_stat->global_auth_tok_list,
> +				 mount_crypt_stat_list) {
> +		list_del(&auth_tok->mount_crypt_stat_list);
> +		mount_crypt_stat->num_global_auth_toks--;
> +		if (auth_tok->global_auth_tok_key
> +		    && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
> +			key_put(auth_tok->global_auth_tok_key);
> +		kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
> +	}
> +	mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
>  	memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
>  }
>  
> @@ -931,6 +954,30 @@ static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
>  		crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
>  }
>  
> +static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
> +	struct ecryptfs_crypt_stat *crypt_stat,
> +	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
> +{
> +	struct ecryptfs_global_auth_tok *global_auth_tok;
> +	int rc = 0;
> +
> +	mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
> +	list_for_each_entry(global_auth_tok,
> +			    &mount_crypt_stat->global_auth_tok_list,
> +			    mount_crypt_stat_list) {
> +		rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
> +		if (rc) {
> +			printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
> +			mutex_unlock(
> +				&mount_crypt_stat->global_auth_tok_list_mutex);
> +			goto out;
> +		}
> +	}
> +	mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
> +out:
> +	return rc;
> +}
> +
>  /**
>   * ecryptfs_set_default_crypt_stat_vals
>   * @crypt_stat
> @@ -973,46 +1020,44 @@ static void ecryptfs_set_default_crypt_stat_vals(
>  /* Associate an authentication token(s) with the file */
>  int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
>  {
> -	int rc = 0;
>  	struct ecryptfs_crypt_stat *crypt_stat =
>  	    &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
>  	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
>  	    &ecryptfs_superblock_to_private(
>  		    ecryptfs_dentry->d_sb)->mount_crypt_stat;
>  	int cipher_name_len;
> +	int rc = 0;
>  
>  	ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
> -	/* See if there are mount crypt options */
> -	if (mount_crypt_stat->global_auth_tok) {
> -		ecryptfs_printk(KERN_DEBUG, "Initializing context for new "
> -				"file using mount_crypt_stat\n");
> -		crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
> -		crypt_stat->flags |= ECRYPTFS_KEY_VALID;
> -		ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
> -							      mount_crypt_stat);
> -		memcpy(crypt_stat->keysigs[crypt_stat->num_keysigs++],
> -		       mount_crypt_stat->global_auth_tok_sig,
> -		       ECRYPTFS_SIG_SIZE_HEX);
> -		cipher_name_len =
> -		    strlen(mount_crypt_stat->global_default_cipher_name);
> -		memcpy(crypt_stat->cipher,
> -		       mount_crypt_stat->global_default_cipher_name,
> -		       cipher_name_len);
> -		crypt_stat->cipher[cipher_name_len] = '\0';
> -		crypt_stat->key_size =
> -			mount_crypt_stat->global_default_cipher_key_size;
> -		ecryptfs_generate_new_key(crypt_stat);
> -	} else
> -		/* We should not encounter this scenario since we
> -		 * should detect lack of global_auth_tok at mount time
> -		 * TODO: Applies to 0.1 release only; remove in future
> -		 * release */
> -		BUG();
> +	mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
> +	BUG_ON(mount_crypt_stat->num_global_auth_toks == 0);
> +	mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
> +	crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
> +	crypt_stat->flags |= ECRYPTFS_KEY_VALID;
> +	ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
> +						      mount_crypt_stat);
> +	rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
> +							 mount_crypt_stat);
> +	if (rc) {
> +		printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
> +		       "to the inode key sigs; rc = [%d]\n", rc);
> +		goto out;
> +	}
> +	cipher_name_len =
> +		strlen(mount_crypt_stat->global_default_cipher_name);
> +	memcpy(crypt_stat->cipher,
> +	       mount_crypt_stat->global_default_cipher_name,
> +	       cipher_name_len);
> +	crypt_stat->cipher[cipher_name_len] = '\0';
> +	crypt_stat->key_size =
> +		mount_crypt_stat->global_default_cipher_key_size;
> +	ecryptfs_generate_new_key(crypt_stat);
>  	rc = ecryptfs_init_crypt_ctx(crypt_stat);
>  	if (rc)
>  		ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
>  				"context for cipher [%s]: rc = [%d]\n",
>  				crypt_stat->cipher, rc);
> +out:
>  	return rc;
>  }
>  
> @@ -1776,7 +1821,7 @@ out:
>  }
>  
>  /**
> - * ecryptfs_process_cipher - Perform cipher initialization.
> + * ecryptfs_process_key_cipher - Perform key cipher initialization.
>   * @key_tfm: Crypto context for key material, set by this function
>   * @cipher_name: Name of the cipher
>   * @key_size: Size of the key in bytes
> @@ -1786,8 +1831,8 @@ out:
>   * event, regardless of whether this function succeeds for fails.
>   */
>  int
> -ecryptfs_process_cipher(struct crypto_blkcipher **key_tfm, char *cipher_name,
> -			size_t *key_size)
> +ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
> +			    char *cipher_name, size_t *key_size)
>  {
>  	char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
>  	char *full_alg_name;
> @@ -1829,3 +1874,98 @@ ecryptfs_process_cipher(struct crypto_blkcipher **key_tfm, char *cipher_name,
>  out:
>  	return rc;
>  }
> +
> +struct kmem_cache *ecryptfs_key_tfm_cache;
> +struct list_head key_tfm_list;
> +struct mutex key_tfm_list_mutex;
> +
> +int ecryptfs_init_crypto(void)
> +{
> +	mutex_init(&key_tfm_list_mutex);
> +	INIT_LIST_HEAD(&key_tfm_list);
> +	return 0;
> +}
> +
> +int ecryptfs_destruct_crypto(void)
> +{
> +	struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
> +
> +	mutex_lock(&key_tfm_list_mutex);
> +	list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
> +				 key_tfm_list) {
> +		list_del(&key_tfm->key_tfm_list);
> +		if (key_tfm->key_tfm)
> +			crypto_free_blkcipher(key_tfm->key_tfm);
> +		kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
> +	}
> +	mutex_unlock(&key_tfm_list_mutex);
> +	return 0;
> +}
> +
> +int
> +ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
> +			 size_t key_size)
> +{
> +	struct ecryptfs_key_tfm *tmp_tfm;
> +	int rc = 0;
> +
> +	tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
> +	if (key_tfm != NULL)
> +		(*key_tfm) = tmp_tfm;
> +	if (!tmp_tfm) {
> +		rc = -ENOMEM;
> +		printk(KERN_ERR "Error attempting to allocate from "
> +		       "ecryptfs_key_tfm_cache\n");
> +		goto out;
> +	}
> +	mutex_init(&tmp_tfm->key_tfm_mutex);
> +	strncpy(tmp_tfm->cipher_name, cipher_name,
> +		ECRYPTFS_MAX_CIPHER_NAME_SIZE);
> +	tmp_tfm->key_size = key_size;
> +	if ((rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
> +					      tmp_tfm->cipher_name,
> +					      &tmp_tfm->key_size))) {
> +		printk(KERN_ERR "Error attempting to initialize key TFM "
> +		       "cipher with name = [%s]; rc = [%d]\n",
> +		       tmp_tfm->cipher_name, rc);
> +		kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
> +		if (key_tfm != NULL)
> +			(*key_tfm) = NULL;
> +		goto out;
> +	}
> +	mutex_lock(&key_tfm_list_mutex);
> +	list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
> +	mutex_unlock(&key_tfm_list_mutex);
> +out:
> +	return rc;
> +}
> +
> +int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
> +					       struct mutex **tfm_mutex,
> +					       char *cipher_name)
> +{
> +	struct ecryptfs_key_tfm *key_tfm;
> +	int rc = 0;
> +
> +	(*tfm) = NULL;
> +	(*tfm_mutex) = NULL;
> +	mutex_lock(&key_tfm_list_mutex);
> +	list_for_each_entry(key_tfm, &key_tfm_list, key_tfm_list) {
> +		if (strcmp(key_tfm->cipher_name, cipher_name) == 0) {
> +			(*tfm) = key_tfm->key_tfm;
> +			(*tfm_mutex) = &key_tfm->key_tfm_mutex;
> +			mutex_unlock(&key_tfm_list_mutex);
> +			goto out;
> +		}
> +	}
> +	mutex_unlock(&key_tfm_list_mutex);
> +	if ((rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0))) {
> +		printk(KERN_ERR "Error adding new key_tfm to list; rc = [%d]\n",
> +		       rc);
> +		goto out;
> +	}
> +	(*tfm) = key_tfm->key_tfm;
> +	(*tfm_mutex) = &key_tfm->key_tfm_mutex;
> +out:
> +	return rc;
> +}
> diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
> index 1b9dd9a..6ddab6c 100644
> --- a/fs/ecryptfs/ecryptfs_kernel.h
> +++ b/fs/ecryptfs/ecryptfs_kernel.h
> @@ -48,10 +48,12 @@
>  #define ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH 0x00000004
>  #define ECRYPTFS_VERSIONING_POLICY                0x00000008
>  #define ECRYPTFS_VERSIONING_XATTR                 0x00000010
> +#define ECRYPTFS_VERSIONING_MULTKEY               0x00000020
>  #define ECRYPTFS_VERSIONING_MASK (ECRYPTFS_VERSIONING_PASSPHRASE \
>  				  | ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH \
>  				  | ECRYPTFS_VERSIONING_PUBKEY \
> -				  | ECRYPTFS_VERSIONING_XATTR)
> +				  | ECRYPTFS_VERSIONING_XATTR \
> +				  | ECRYPTFS_VERSIONING_MULTKEY)
>  #define ECRYPTFS_MAX_PASSWORD_LENGTH 64
>  #define ECRYPTFS_MAX_PASSPHRASE_BYTES ECRYPTFS_MAX_PASSWORD_LENGTH
>  #define ECRYPTFS_SALT_SIZE 8
> @@ -144,6 +146,7 @@ struct ecryptfs_private_key {
>  struct ecryptfs_auth_tok {
>  	u16 version; /* 8-bit major and 8-bit minor */
>  	u16 token_type;
> +#define ECRYPTFS_ENCRYPT_ONLY 0x00000001
>  	u32 flags;
>  	struct ecryptfs_session_key session_key;
>  	u8 reserved[32];
> @@ -153,6 +156,7 @@ struct ecryptfs_auth_tok {
>  	} token;
>  } __attribute__ ((packed));
>  
> +int ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok);
>  void ecryptfs_dump_auth_tok(struct ecryptfs_auth_tok *auth_tok);
>  extern void ecryptfs_to_hex(char *dst, char *src, size_t src_size);
>  extern void ecryptfs_from_hex(char *dst, char *src, int dst_size);
> @@ -194,7 +198,6 @@ ecryptfs_get_key_payload_data(struct key *key)
>  #define ECRYPTFS_MAX_KEYSET_SIZE 1024
>  #define ECRYPTFS_MAX_CIPHER_NAME_SIZE 32
>  #define ECRYPTFS_MAX_NUM_ENC_KEYS 64
> -#define ECRYPTFS_MAX_NUM_KEYSIGS 2 /* TODO: Make this a linked list */
>  #define ECRYPTFS_MAX_IV_BYTES 16	/* 128 bits */
>  #define ECRYPTFS_SALT_BYTES 2
>  #define MAGIC_ECRYPTFS_MARKER 0x3c81b7f5
> @@ -212,6 +215,11 @@ ecryptfs_get_key_payload_data(struct key *key)
>  #define ECRYPTFS_TAG_67_PACKET_TYPE 0x43
>  #define MD5_DIGEST_SIZE 16
>  
> +struct ecryptfs_key_sig {
> +	struct list_head crypt_stat_list;
> +	char keysig[ECRYPTFS_SIG_SIZE_HEX];
> +};
> +
>  /**
>   * This is the primary struct associated with each encrypted file.
>   *
> @@ -231,7 +239,6 @@ struct ecryptfs_crypt_stat {
>  	u32 flags;
>  	unsigned int file_version;
>  	size_t iv_bytes;
> -	size_t num_keysigs;
>  	size_t header_extent_size;
>  	size_t num_header_extents_at_front;
>  	size_t extent_size; /* Data extent size; default is 4096 */
> @@ -245,7 +252,8 @@ struct ecryptfs_crypt_stat {
>  	unsigned char cipher[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
>  	unsigned char key[ECRYPTFS_MAX_KEY_BYTES];
>  	unsigned char root_iv[ECRYPTFS_MAX_IV_BYTES];
> -	unsigned char keysigs[ECRYPTFS_MAX_NUM_KEYSIGS][ECRYPTFS_SIG_SIZE_HEX];
> +	struct list_head keysig_list;
> +	struct mutex keysig_list_mutex;
>  	struct mutex cs_tfm_mutex;
>  	struct mutex cs_hash_tfm_mutex;
>  	struct mutex cs_mutex;
> @@ -265,6 +273,26 @@ struct ecryptfs_dentry_info {
>  	struct ecryptfs_crypt_stat *crypt_stat;
>  };
>  
> +struct ecryptfs_global_auth_tok {
> +#define ECRYPTFS_AUTH_TOK_INVALID 0x00000001
> +	u32 flags;
> +	struct list_head mount_crypt_stat_list;
> +	struct key *global_auth_tok_key;
> +	struct ecryptfs_auth_tok *global_auth_tok;
> +	unsigned char sig[ECRYPTFS_SIG_SIZE_HEX + 1];
> +};
> +
> +struct ecryptfs_key_tfm {
> +	struct crypto_blkcipher *key_tfm;
> +	size_t key_size;
> +	struct mutex key_tfm_mutex;
> +	struct list_head key_tfm_list;
> +	unsigned char cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
> +};
> +
> +extern struct list_head key_tfm_list;
> +extern struct mutex key_tfm_list_mutex;
> +
>  /**
>   * This struct is to enable a mount-wide passphrase/salt combo. This
>   * is more or less a stopgap to provide similar functionality to other
> @@ -276,15 +304,14 @@ struct ecryptfs_mount_crypt_stat {
>  #define ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED 0x00000001
>  #define ECRYPTFS_XATTR_METADATA_ENABLED        0x00000002
>  #define ECRYPTFS_ENCRYPTED_VIEW_ENABLED        0x00000004
> +#define ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED  0x00000008
>  	u32 flags;
> -	struct ecryptfs_auth_tok *global_auth_tok;
> -	struct key *global_auth_tok_key;
> +	struct list_head global_auth_tok_list;
> +	struct mutex global_auth_tok_list_mutex;
> +	size_t num_global_auth_toks;
>  	size_t global_default_cipher_key_size;
> -	struct crypto_blkcipher *global_key_tfm;
> -	struct mutex global_key_tfm_mutex;
>  	unsigned char global_default_cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE
>  						 + 1];
> -	unsigned char global_auth_tok_sig[ECRYPTFS_SIG_SIZE_HEX + 1];
>  };
>  
>  /* superblock private data. */
> @@ -468,6 +495,9 @@ extern struct kmem_cache *ecryptfs_header_cache_2;
>  extern struct kmem_cache *ecryptfs_xattr_cache;
>  extern struct kmem_cache *ecryptfs_lower_page_cache;
>  extern struct kmem_cache *ecryptfs_key_record_cache;
> +extern struct kmem_cache *ecryptfs_key_sig_cache;
> +extern struct kmem_cache *ecryptfs_global_auth_tok_cache;
> +extern struct kmem_cache *ecryptfs_key_tfm_cache;
>  
>  int ecryptfs_interpose(struct dentry *hidden_dentry,
>  		       struct dentry *this_dentry, struct super_block *sb,
> @@ -538,9 +568,8 @@ int
>  ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
>  			  unsigned char *src, struct dentry *ecryptfs_dentry);
>  int ecryptfs_truncate(struct dentry *dentry, loff_t new_length);
> -int
> -ecryptfs_process_cipher(struct crypto_blkcipher **key_tfm, char *cipher_name,
> -			size_t *key_size);
> +int ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
> +				char *cipher_name, size_t *key_size);
>  int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode);
>  int ecryptfs_inode_set(struct inode *inode, void *lower_inode);
>  void ecryptfs_init_inode(struct inode *inode, struct inode *lower_inode);
> @@ -580,6 +609,24 @@ void
>  ecryptfs_write_header_metadata(char *virt,
>  			       struct ecryptfs_crypt_stat *crypt_stat,
>  			       size_t *written);
> +int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig);
> +int
> +ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
> +			   char *sig);
> +int ecryptfs_get_global_auth_tok_for_sig(
> +	struct ecryptfs_global_auth_tok **global_auth_tok,
> +	struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig);
> +int
> +ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
> +			 size_t key_size);
> +int ecryptfs_init_crypto(void);
> +int ecryptfs_destruct_crypto(void);
> +int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
> +					       struct mutex **tfm_mutex,
> +					       char *cipher_name);
> +int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
> +				      struct ecryptfs_auth_tok **auth_tok,
> +				      char *sig);
>  int ecryptfs_write_zeros(struct file *file, pgoff_t index, int start,
>  			 int num_zeros);
>  
> diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c
> index b550dea..ef4904a 100644
> --- a/fs/ecryptfs/keystore.c
> +++ b/fs/ecryptfs/keystore.c
> @@ -402,20 +402,24 @@ out:
>   *
>   * Returns Zero on success; non-zero error otherwise.
>   */
> -static int decrypt_pki_encrypted_session_key(
> -	struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
> -	struct ecryptfs_auth_tok *auth_tok,
> -	struct ecryptfs_crypt_stat *crypt_stat)
> +static int
> +decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
> +				  struct ecryptfs_crypt_stat *crypt_stat)
>  {
>  	u16 cipher_code = 0;
>  	struct ecryptfs_msg_ctx *msg_ctx;
>  	struct ecryptfs_message *msg = NULL;
> +	char *auth_tok_sig;
>  	char *netlink_message;
>  	size_t netlink_message_length;
>  	int rc;
>  
> -	rc = write_tag_64_packet(mount_crypt_stat->global_auth_tok_sig,
> -				 &(auth_tok->session_key),
> +	if ((rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok))) {
> +		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),
>  				 &netlink_message, &netlink_message_length);
>  	if (rc) {
>  		ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet");
> @@ -921,126 +925,241 @@ out:
>  	return rc;
>  }
>  
> +static int
> +ecryptfs_find_global_auth_tok_for_sig(
> +	struct ecryptfs_global_auth_tok **global_auth_tok,
> +	struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
> +{
> +	struct ecryptfs_global_auth_tok *walker;
> +	int rc = 0;
> +
> +	(*global_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) == 0) {
> +			(*global_auth_tok) = walker;
> +			goto out;
> +		}
> +	}
> +	rc = -EINVAL;
> +out:
> +	mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
> +	return rc;
> +}
> +
>  /**
> - * decrypt_session_key - Decrypt the session key with the given auth_tok.
> + * 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;
> +}
> +
> +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 (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
> +		printk(KERN_ERR "Could not find key with description: [%s]\n",
> +		       sig);
> +		process_request_key_err(PTR_ERR(*auth_tok_key));
> +		rc = -EINVAL;
> +		goto out;
> +	}
> +	(*auth_tok) = ecryptfs_get_key_payload_data(*auth_tok_key);
> +	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;
> +}
> +
> +/**
> + * ecryptfs_find_auth_tok_for_sig
> + * @auth_tok: Set to the matching auth_tok; NULL if not found
> + * @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 ecryptfs_auth_tok **auth_tok,
> +	struct ecryptfs_crypt_stat *crypt_stat, char *sig)
> +{
> +	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
> +		crypt_stat->mount_crypt_stat;
> +	struct ecryptfs_global_auth_tok *global_auth_tok;
> +	int rc = 0;
> +
> +	(*auth_tok) = NULL;
> +	if (ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok,
> +						  mount_crypt_stat, sig)) {
> +		struct key *auth_tok_key;
> +
> +		rc = ecryptfs_keyring_auth_tok_for_sig(&auth_tok_key, auth_tok,
> +						       sig);
> +	} else
> +		(*auth_tok) = global_auth_tok->global_auth_tok;
> +	return rc;
> +}
> +
> +/**
> + * decrypt_passphrase_encrypted_session_key - Decrypt the session key
> + * with the given auth_tok.
>   *
>   * Returns Zero on success; non-zero error otherwise.
>   */
> -static int decrypt_session_key(struct ecryptfs_auth_tok *auth_tok,
> -			       struct ecryptfs_crypt_stat *crypt_stat)
> +static int
> +decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
> +					 struct ecryptfs_crypt_stat *crypt_stat)
>  {
> -	struct ecryptfs_password *password_s_ptr;
> -	struct scatterlist src_sg[2], dst_sg[2];
> +	struct scatterlist dst_sg;
> +	struct scatterlist src_sg;
>  	struct mutex *tfm_mutex = NULL;
> -	char *encrypted_session_key;
> -	char *session_key;
>  	struct blkcipher_desc desc = {
>  		.flags = CRYPTO_TFM_REQ_MAY_SLEEP
>  	};
>  	int rc = 0;
>  
> -	password_s_ptr = &auth_tok->token.password;
> -	if (password_s_ptr->flags & ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET)
> -		ecryptfs_printk(KERN_DEBUG, "Session key encryption key "
> -				"set; skipping key generation\n");
> -	ecryptfs_printk(KERN_DEBUG, "Session key encryption key (size [%d])"
> -			":\n",
> -			password_s_ptr->session_key_encryption_key_bytes);
> -	if (ecryptfs_verbosity > 0)
> -		ecryptfs_dump_hex(password_s_ptr->session_key_encryption_key,
> -				  password_s_ptr->
> -				  session_key_encryption_key_bytes);
> -	if (!strcmp(crypt_stat->cipher,
> -		    crypt_stat->mount_crypt_stat->global_default_cipher_name)
> -	    && crypt_stat->mount_crypt_stat->global_key_tfm) {
> -		desc.tfm = crypt_stat->mount_crypt_stat->global_key_tfm;
> -		tfm_mutex = &crypt_stat->mount_crypt_stat->global_key_tfm_mutex;
> -	} else {
> -		char *full_alg_name;
> -
> -		rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
> -							    crypt_stat->cipher,
> -							    "ecb");
> -		if (rc)
> -			goto out;
> -		desc.tfm = crypto_alloc_blkcipher(full_alg_name, 0,
> -						  CRYPTO_ALG_ASYNC);
> -		kfree(full_alg_name);
> -		if (IS_ERR(desc.tfm)) {
> -			rc = PTR_ERR(desc.tfm);
> -			printk(KERN_ERR "Error allocating crypto context; "
> -			       "rc = [%d]\n", rc);
> -			goto out;
> -		}
> -		crypto_blkcipher_set_flags(desc.tfm, CRYPTO_TFM_REQ_WEAK_KEY);
> +	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(&desc.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 (tfm_mutex)
> -		mutex_lock(tfm_mutex);
> -	rc = crypto_blkcipher_setkey(desc.tfm,
> -				     password_s_ptr->session_key_encryption_key,
> -				     crypt_stat->key_size);
> -	if (rc < 0) {
> +	if ((rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
> +				      auth_tok->session_key.encrypted_key_size,
> +				      &src_sg, 1)) != 1) {
> +		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;
> +	if ((rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
> +				      auth_tok->session_key.decrypted_key_size,
> +				      &dst_sg, 1)) != 1) {
> +		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);
> +	rc = crypto_blkcipher_setkey(
> +		desc.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_free_tfm;
> -	}
> -	/* TODO: virt_to_scatterlist */
> -	encrypted_session_key = (char *)__get_free_page(GFP_KERNEL);
> -	if (!encrypted_session_key) {
> -		ecryptfs_printk(KERN_ERR, "Out of memory\n");
> -		rc = -ENOMEM;
> -		goto out_free_tfm;
> +		goto out;
>  	}
> -	session_key = (char *)__get_free_page(GFP_KERNEL);
> -	if (!session_key) {
> -		kfree(encrypted_session_key);
> -		ecryptfs_printk(KERN_ERR, "Out of memory\n");
> -		rc = -ENOMEM;
> -		goto out_free_tfm;
> -	}
> -	memcpy(encrypted_session_key, auth_tok->session_key.encrypted_key,
> -	       auth_tok->session_key.encrypted_key_size);
> -	src_sg[0].page = virt_to_page(encrypted_session_key);
> -	src_sg[0].offset = 0;
> -	BUG_ON(auth_tok->session_key.encrypted_key_size > PAGE_CACHE_SIZE);
> -	src_sg[0].length = auth_tok->session_key.encrypted_key_size;
> -	dst_sg[0].page = virt_to_page(session_key);
> -	dst_sg[0].offset = 0;
> -	auth_tok->session_key.decrypted_key_size =
> -	    auth_tok->session_key.encrypted_key_size;
> -	dst_sg[0].length = auth_tok->session_key.encrypted_key_size;
> -	rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg,
> +	rc = crypto_blkcipher_decrypt(&desc, &dst_sg, &src_sg,
>  				      auth_tok->session_key.encrypted_key_size);
> -	if (rc) {
> +	mutex_unlock(tfm_mutex);
> +	if (unlikely(rc)) {
>  		printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
> -		goto out_free_memory;
> +		goto out;
>  	}
> -	auth_tok->session_key.decrypted_key_size =
> -	    auth_tok->session_key.encrypted_key_size;
> -	memcpy(auth_tok->session_key.decrypted_key, session_key,
> -	       auth_tok->session_key.decrypted_key_size);
>  	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;
> -	ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
> -	if (ecryptfs_verbosity > 0)
> +	if (unlikely(ecryptfs_verbosity > 0)) {
> +		ecryptfs_printk(KERN_DEBUG, "FEK of size [%d]:\n",
> +				crypt_stat->key_size);
>  		ecryptfs_dump_hex(crypt_stat->key,
>  				  crypt_stat->key_size);
> -out_free_memory:
> -	memset(encrypted_session_key, 0, PAGE_CACHE_SIZE);
> -	free_page((unsigned long)encrypted_session_key);
> -	memset(session_key, 0, PAGE_CACHE_SIZE);
> -	free_page((unsigned long)session_key);
> -out_free_tfm:
> -	if (tfm_mutex)
> -		mutex_unlock(tfm_mutex);
> -	else
> -		crypto_free_blkcipher(desc.tfm);
> +	}
>  out:
>  	return rc;
>  }
>  
> +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;
> +}
> +
>  /**
>   * ecryptfs_parse_packet_set
>   * @dest: The header page in memory
> @@ -1058,25 +1177,22 @@ int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
>  			      struct dentry *ecryptfs_dentry)
>  {
>  	size_t i = 0;
> -	size_t found_auth_tok = 0;
> +	size_t found_auth_tok;
>  	size_t next_packet_is_auth_tok_packet;
> -	char sig[ECRYPTFS_SIG_SIZE_HEX];
>  	struct list_head auth_tok_list;
> -	struct list_head *walker;
> -	struct ecryptfs_auth_tok *chosen_auth_tok = NULL;
> -	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
> -		&ecryptfs_superblock_to_private(
> -			ecryptfs_dentry->d_sb)->mount_crypt_stat;
> +	struct ecryptfs_auth_tok *matching_auth_tok = NULL;
>  	struct ecryptfs_auth_tok *candidate_auth_tok = NULL;
> +	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;
>  	int rc = 0;
>  
>  	INIT_LIST_HEAD(&auth_tok_list);
> -	/* Parse the header to find as many packets as we can, these will be
> +	/* 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) {
> @@ -1155,73 +1271,86 @@ int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
>  		}
>  	}
>  	if (list_empty(&auth_tok_list)) {
> -		rc = -EINVAL; /* Do not support non-encrypted files in
> -			       * the 0.1 release */
> +		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;
>  	}
> -	/* If we have a global auth tok, then we should try to use
> -	 * it */
> -	if (mount_crypt_stat->global_auth_tok) {
> -		memcpy(sig, mount_crypt_stat->global_auth_tok_sig,
> -		       ECRYPTFS_SIG_SIZE_HEX);
> -		chosen_auth_tok = mount_crypt_stat->global_auth_tok;
> -	} else
> -		BUG(); /* We should always have a global auth tok in
> -			* the 0.1 release */
> -	/* Scan list to see if our chosen_auth_tok works */
> -	list_for_each(walker, &auth_tok_list) {
> -		struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
> -		auth_tok_list_item =
> -		    list_entry(walker, struct ecryptfs_auth_tok_list_item,
> -			       list);
> +	/* 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 cadidate auth tok:\n");
>  			ecryptfs_dump_auth_tok(candidate_auth_tok);
>  		}
> -		/* TODO: Replace ECRYPTFS_SIG_SIZE_HEX w/ dynamic value */
> -		if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD
> -		    && !strncmp(candidate_auth_tok->token.password.signature,
> -				sig, ECRYPTFS_SIG_SIZE_HEX)) {
> -			found_auth_tok = 1;
> -			goto leave_list;
> -			/* TODO: Transfer the common salt into the
> -			 * crypt_stat salt */
> -		} else if ((candidate_auth_tok->token_type
> -			    == ECRYPTFS_PRIVATE_KEY)
> -			   && !strncmp(candidate_auth_tok->token.private_key.signature,
> -				     sig, ECRYPTFS_SIG_SIZE_HEX)) {
> +		if ((rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
> +						    candidate_auth_tok))) {
> +			printk(KERN_ERR
> +			       "Unrecognized candidate auth tok type: [%d]\n",
> +			       candidate_auth_tok->token_type);
> +			rc = -EINVAL;
> +			goto out_wipe_list;
> +		}
> +		if ((rc = ecryptfs_find_auth_tok_for_sig(
> +			     &matching_auth_tok, crypt_stat,
> +			     candidate_auth_tok_sig)))
> +			rc = 0;
> +		if (matching_auth_tok) {
>  			found_auth_tok = 1;
> -			goto leave_list;
> +			goto found_matching_auth_tok;
>  		}
>  	}
>  	if (!found_auth_tok) {
> -		ecryptfs_printk(KERN_ERR, "Could not find authentication "
> -				"token on temporary list for sig [%.*s]\n",
> -				ECRYPTFS_SIG_SIZE_HEX, sig);
> +		ecryptfs_printk(KERN_ERR, "Could not find a usable "
> +				"authentication token\n");
>  		rc = -EIO;
>  		goto out_wipe_list;
>  	}
> -leave_list:
> -	rc = -ENOTSUPP;
> +found_matching_auth_tok:
>  	if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
>  		memcpy(&(candidate_auth_tok->token.private_key),
> -		       &(chosen_auth_tok->token.private_key),
> +		       &(matching_auth_tok->token.private_key),
>  		       sizeof(struct ecryptfs_private_key));
> -		rc = decrypt_pki_encrypted_session_key(mount_crypt_stat,
> -						       candidate_auth_tok,
> +		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),
> -		       &(chosen_auth_tok->token.password),
> +		       &(matching_auth_tok->token.password),
>  		       sizeof(struct ecryptfs_password));
> -		rc = decrypt_session_key(candidate_auth_tok, crypt_stat);
> +		rc = decrypt_passphrase_encrypted_session_key(
> +			candidate_auth_tok, crypt_stat);
>  	}
>  	if (rc) {
> -		ecryptfs_printk(KERN_ERR, "Error decrypting the "
> -				"session key; rc = [%d]\n", rc);
> -		goto out_wipe_list;
> +		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", candidate_auth_tok_sig,
> +				ECRYPTFS_SIG_SIZE_HEX, 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) {
> @@ -1240,6 +1369,7 @@ out_wipe_list:
>  out:
>  	return rc;
>  }
> +
>  static int
>  pki_encrypt_session_key(struct ecryptfs_auth_tok *auth_tok,
>  			struct ecryptfs_crypt_stat *crypt_stat,
> @@ -1291,15 +1421,15 @@ out:
>   * Returns zero on success; non-zero on error.
>   */
>  static int
> -write_tag_1_packet(char *dest, size_t max, struct ecryptfs_auth_tok *auth_tok,
> +write_tag_1_packet(char *dest, size_t *remaining_bytes,
> +		   struct ecryptfs_auth_tok *auth_tok,
>  		   struct ecryptfs_crypt_stat *crypt_stat,
> -		   struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
>  		   struct ecryptfs_key_record *key_rec, size_t *packet_size)
>  {
>  	size_t i;
>  	size_t encrypted_session_key_valid = 0;
> -	size_t key_rec_size;
>  	size_t packet_size_length;
> +	size_t max_packet_size;
>  	int rc = 0;
>  
>  	(*packet_size) = 0;
> @@ -1329,37 +1459,23 @@ write_tag_1_packet(char *dest, size_t max, struct ecryptfs_auth_tok *auth_tok,
>  		ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
>  	}
>  encrypted_session_key_set:
> -	/* Now we have a valid key_rec.  Append it to the
> -	 * key_rec set. */
> -	key_rec_size = (sizeof(struct ecryptfs_key_record)
> -			- ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
> -			+ (key_rec->enc_key_size));
> -	/* TODO: Include a packet size limit as a parameter to this
> -	 * function once we have multi-packet headers (for versions
> -	 * later than 0.1 */
> -	if (key_rec_size >= ECRYPTFS_MAX_KEYSET_SIZE) {
> -		ecryptfs_printk(KERN_ERR, "Keyset too large\n");
> -		rc = -EINVAL;
> -		goto out;
> -	}
> -	/*              ***** TAG 1 Packet Format *****
> -	 *    | version number                     | 1 byte       |
> -	 *    | key ID                             | 8 bytes      |
> -	 *    | public key algorithm               | 1 byte       |
> -	 *    | encrypted session key              | arbitrary    |
> -	 */
> -	if ((0x02 + ECRYPTFS_SIG_SIZE + key_rec->enc_key_size) >= max) {
> -		ecryptfs_printk(KERN_ERR,
> -				"Authentication token is too large\n");
> +	/* 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 [%d] bytes, but there are only [%d] "
> +		       "available\n", max_packet_size, (*remaining_bytes));
>  		rc = -EINVAL;
>  		goto out;
>  	}
>  	dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
> -	/* This format is inspired by OpenPGP; see RFC 2440
> -	 * packet tag 1 */
> -	rc = write_packet_length(&dest[(*packet_size)],
> -				 (0x02 + ECRYPTFS_SIG_SIZE +
> -				 key_rec->enc_key_size),
> +	rc = write_packet_length(&dest[(*packet_size)], (max_packet_size - 4),
>  				 &packet_size_length);
>  	if (rc) {
>  		ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
> @@ -1377,6 +1493,8 @@ encrypted_session_key_set:
>  out:
>  	if (rc)
>  		(*packet_size) = 0;
> +	else
> +		(*remaining_bytes) -= (*packet_size);
>  	return rc;
>  }
>  
> @@ -1448,19 +1566,22 @@ write_tag_11_packet(char *dest, int max, char *contents, size_t contents_length,
>   * Returns zero on success; non-zero on error.
>   */
>  static int
> -write_tag_3_packet(char *dest, size_t max, struct ecryptfs_auth_tok *auth_tok,
> +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 dest_sg[2];
> -	struct scatterlist src_sg[2];
> +	struct scatterlist dst_sg;
> +	struct scatterlist src_sg;
>  	struct mutex *tfm_mutex = NULL;
> -	size_t key_rec_size;
> -	size_t packet_size_length;
>  	size_t 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 blkcipher_desc desc = {
>  		.tfm = NULL,
>  		.flags = CRYPTO_TFM_REQ_MAY_SLEEP
> @@ -1470,16 +1591,25 @@ write_tag_3_packet(char *dest, size_t max, struct ecryptfs_auth_tok *auth_tok,
>  	(*packet_size) = 0;
>  	ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.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);
> -		goto encrypted_session_key_set;
> +	rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.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) {
> +		struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
> +
> +		printk(KERN_WARNING "No key size specified at mount; "
> +		       "defaulting to [%d]\n", alg->max_keysize);
> +		mount_crypt_stat->global_default_cipher_key_size =
> +			alg->max_keysize;
>  	}
> +	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;
> @@ -1487,9 +1617,24 @@ write_tag_3_packet(char *dest, size_t max, struct ecryptfs_auth_tok *auth_tok,
>  	    && 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 = [%d]\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 "
> @@ -1508,54 +1653,32 @@ write_tag_3_packet(char *dest, size_t max, struct ecryptfs_auth_tok *auth_tok,
>  		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) {
> +	if ((rc = virt_to_scatterlist(crypt_stat->key,
> +				      key_rec->enc_key_size, &src_sg, 1))
> +	    != 1) {
>  		ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
> -				"for crypt_stat session key\n");
> +				"for crypt_stat session key; expected rc = 1; "
> +				"got rc = [%d]. key_rec->enc_key_size = [%d]\n",
> +				rc, key_rec->enc_key_size);
>  		rc = -ENOMEM;
>  		goto out;
>  	}
> -	rc = virt_to_scatterlist(key_rec->enc_key,
> -				 key_rec->enc_key_size, dest_sg, 2);
> -	if (!rc) {
> +	if ((rc = virt_to_scatterlist(key_rec->enc_key,
> +				      key_rec->enc_key_size, &dst_sg, 1))
> +	    != 1) {
>  		ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
> -				"for crypt_stat encrypted session key\n");
> +				"for crypt_stat encrypted session key; "
> +				"expected rc = 1; got rc = [%d]. "
> +				"key_rec->enc_key_size = [%d]\n", rc,
> +				key_rec->enc_key_size);
>  		rc = -ENOMEM;
>  		goto out;
>  	}
> -	if (!strcmp(crypt_stat->cipher,
> -		    crypt_stat->mount_crypt_stat->global_default_cipher_name)
> -	    && crypt_stat->mount_crypt_stat->global_key_tfm) {
> -		desc.tfm = crypt_stat->mount_crypt_stat->global_key_tfm;
> -		tfm_mutex = &crypt_stat->mount_crypt_stat->global_key_tfm_mutex;
> -	} else {
> -		char *full_alg_name;
> -
> -		rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
> -							    crypt_stat->cipher,
> -							    "ecb");
> -		if (rc)
> -			goto out;
> -		desc.tfm = crypto_alloc_blkcipher(full_alg_name, 0,
> -						  CRYPTO_ALG_ASYNC);
> -		kfree(full_alg_name);
> -		if (IS_ERR(desc.tfm)) {
> -			rc = PTR_ERR(desc.tfm);
> -			ecryptfs_printk(KERN_ERR, "Could not initialize crypto "
> -					"context for cipher [%s]; rc = [%d]\n",
> -					crypt_stat->cipher, rc);
> -			goto out;
> -		}
> -		crypto_blkcipher_set_flags(desc.tfm, CRYPTO_TFM_REQ_WEAK_KEY);
> -	}
> -	if (tfm_mutex)
> -		mutex_lock(tfm_mutex);
> +	mutex_lock(tfm_mutex);
>  	rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
>  				     crypt_stat->key_size);
>  	if (rc < 0) {
> -		if (tfm_mutex)
> -			mutex_unlock(tfm_mutex);
> +		mutex_unlock(tfm_mutex);
>  		ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
>  				"context; rc = [%d]\n", rc);
>  		goto out;
> @@ -1563,56 +1686,53 @@ write_tag_3_packet(char *dest, size_t max, struct ecryptfs_auth_tok *auth_tok,
>  	rc = 0;
>  	ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes of the key\n",
>  			crypt_stat->key_size);
> -	rc = crypto_blkcipher_encrypt(&desc, dest_sg, src_sg,
> +	rc = crypto_blkcipher_encrypt(&desc, &dst_sg, &src_sg,
>  				      (*key_rec).enc_key_size);
> +	mutex_unlock(tfm_mutex);
>  	if (rc) {
>  		printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
>  		goto out;
>  	}
> -	if (tfm_mutex)
> -		mutex_unlock(tfm_mutex);
>  	ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
> -	if (ecryptfs_verbosity > 0)
> +	if (ecryptfs_verbosity > 0) {
> +		ecryptfs_printk(KERN_DEBUG, "EFEK of size [%d]:\n",
> +				key_rec->enc_key_size);
>  		ecryptfs_dump_hex(key_rec->enc_key,
>  				  key_rec->enc_key_size);
> -encrypted_session_key_set:
> -	/* Now we have a valid key_rec.  Append it to the
> -	 * key_rec set. */
> -	key_rec_size = (sizeof(struct ecryptfs_key_record)
> -			- ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
> -			+ (key_rec->enc_key_size));
> -	/* TODO: Include a packet size limit as a parameter to this
> -	 * function once we have multi-packet headers (for versions
> -	 * later than 0.1 */
> -	if (key_rec_size >= ECRYPTFS_MAX_KEYSET_SIZE) {
> -		ecryptfs_printk(KERN_ERR, "Keyset too large\n");
> -		rc = -EINVAL;
> -		goto out;
>  	}
> -	/* TODO: Packet size limit */
> -	/* We have 5 bytes of surrounding packet data */
> -	if ((0x05 + ECRYPTFS_SALT_SIZE
> -	     + key_rec->enc_key_size) >= max) {
> -		ecryptfs_printk(KERN_ERR, "Authentication token is too "
> -				"large\n");
> +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 [%d] bytes, but "
> +		       "there are only [%d] available\n", max_packet_size,
> +		       (*remaining_bytes));
>  		rc = -EINVAL;
>  		goto out;
>  	}
> -	/* This format is inspired by OpenPGP; see RFC 2440
> -	 * packet tag 3 */
>  	dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
> -	/* ver+cipher+s2k+hash+salt+iter+enc_key */
> -	rc = write_packet_length(&dest[(*packet_size)],
> -				 (0x05 + ECRYPTFS_SALT_SIZE
> -				  + key_rec->enc_key_size),
> +	/* 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 = write_packet_length(&dest[(*packet_size)], (max_packet_size - 4),
>  				 &packet_size_length);
>  	if (rc) {
> -		ecryptfs_printk(KERN_ERR, "Error generating tag 3 packet "
> -				"header; cannot generate packet length\n");
> +		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);
>  	if (cipher_code == 0) {
>  		ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
> @@ -1631,10 +1751,10 @@ encrypted_session_key_set:
>  	       key_rec->enc_key_size);
>  	(*packet_size) += key_rec->enc_key_size;
>  out:
> -	if (desc.tfm && !tfm_mutex)
> -		crypto_free_blkcipher(desc.tfm);
>  	if (rc)
>  		(*packet_size) = 0;
> +	else
> +		(*remaining_bytes) -= (*packet_size);
>  	return rc;
>  }
>  
> @@ -1662,24 +1782,43 @@ ecryptfs_generate_key_packet_set(char *dest_base,
>  				 size_t max)
>  {
>  	struct ecryptfs_auth_tok *auth_tok;
> +	struct ecryptfs_global_auth_tok *global_auth_tok;
>  	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;
>  	}
> -	if (mount_crypt_stat->global_auth_tok) {
> -		auth_tok = mount_crypt_stat->global_auth_tok;
> +	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(&global_auth_tok,
> +							   mount_crypt_stat,
> +							   key_sig->keysig);
> +		if (rc) {
> +			printk(KERN_ERR "Error attempting to get the global "
> +			       "auth_tok; rc = [%d]\n", rc);
> +			goto out_free;
> +		}
> +		if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID) {
> +			printk(KERN_WARNING
> +			       "Skipping invalid auth tok with sig = [%s]\n",
> +			       global_auth_tok->sig);
> +			continue;
> +		}
> +		auth_tok = global_auth_tok->global_auth_tok;
>  		if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
>  			rc = write_tag_3_packet((dest_base + (*len)),
> -						max, auth_tok,
> +						&max, auth_tok,
>  						crypt_stat, key_rec,
>  						&written);
>  			if (rc) {
> @@ -1689,10 +1828,9 @@ ecryptfs_generate_key_packet_set(char *dest_base,
>  			}
>  			(*len) += written;
>  			/* Write auth tok signature packet */
> -			rc = write_tag_11_packet(
> -				(dest_base + (*len)),
> -				(max - (*len)),
> -				key_rec->sig, ECRYPTFS_SIG_SIZE, &written);
> +			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");
> @@ -1701,9 +1839,8 @@ ecryptfs_generate_key_packet_set(char *dest_base,
>  			(*len) += written;
>  		} else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
>  			rc = write_tag_1_packet(dest_base + (*len),
> -						max, auth_tok,
> -						crypt_stat,mount_crypt_stat,
> -						key_rec, &written);
> +						&max, auth_tok,
> +						crypt_stat, key_rec, &written);
>  			if (rc) {
>  				ecryptfs_printk(KERN_WARNING, "Error "
>  						"writing tag 1 packet\n");
> @@ -1716,19 +1853,69 @@ ecryptfs_generate_key_packet_set(char *dest_base,
>  			rc = -EINVAL;
>  			goto out_free;
>  		}
> -	} else
> -		BUG();
> -	if (likely((max - (*len)) > 0)) {
> +	}
> +	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;
> +	int rc = 0;
> +
> +	new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
> +	if (!new_key_sig) {
> +		rc = -ENOMEM;
> +		printk(KERN_ERR
> +		       "Error allocating from ecryptfs_key_sig_cache\n");
> +		goto out;
> +	}
> +	memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
> +	mutex_lock(&crypt_stat->keysig_list_mutex);
> +	list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
> +	mutex_unlock(&crypt_stat->keysig_list_mutex);
> +out:
>  	return rc;
>  }
> +
> +struct kmem_cache *ecryptfs_global_auth_tok_cache;
> +
> +int
> +ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
> +			     char *sig)
> +{
> +	struct ecryptfs_global_auth_tok *new_auth_tok;
> +	int rc = 0;
> +
> +	new_auth_tok = kmem_cache_alloc(ecryptfs_global_auth_tok_cache,
> +					GFP_KERNEL);
> +	if (!new_auth_tok) {
> +		rc = -ENOMEM;
> +		printk(KERN_ERR "Error allocating from "
> +		       "ecryptfs_global_auth_tok_cache\n");
> +		goto out;
> +	}
> +	memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
> +	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);
> +	mount_crypt_stat->num_global_auth_toks++;
> +	mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
> +out:
> +	return rc;
> +}
> +
> diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
> index 606128f..5da6180 100644
> --- a/fs/ecryptfs/main.c
> +++ b/fs/ecryptfs/main.c
> @@ -179,38 +179,40 @@ static match_table_t tokens = {
>  	{ecryptfs_opt_err, NULL}
>  };
>  
> -/**
> - * ecryptfs_verify_version
> - * @version: The version number to confirm
> - *
> - * Returns zero on good version; non-zero otherwise
> - */
> -static int ecryptfs_verify_version(u16 version)
> +static int ecryptfs_init_global_auth_toks(
> +	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
>  {
> +	struct ecryptfs_global_auth_tok *global_auth_tok;
>  	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;
> +
> +	list_for_each_entry(global_auth_tok,
> +			    &mount_crypt_stat->global_auth_tok_list,
> +			    mount_crypt_stat_list) {
> +		if ((rc = ecryptfs_keyring_auth_tok_for_sig(
> +			     &global_auth_tok->global_auth_tok_key,
> +			     &global_auth_tok->global_auth_tok,
> +			     global_auth_tok->sig))) {
> +			printk(KERN_ERR "Could not find valid key in user "
> +			       "session keyring for sig specified in mount "
> +			       "option: [%s]\n", global_auth_tok->sig);
> +			global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
> +			rc = 0;
> +		} else
> +			global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
>  	}
> -out:
>  	return rc;
>  }
>  
> +static void ecryptfs_init_mount_crypt_stat(
> +	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
> +{
> +	memset((void *)mount_crypt_stat, 0,
> +	       sizeof(struct ecryptfs_mount_crypt_stat));
> +	INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
> +	mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
> +	mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
> +}
> +
>  /**
>   * ecryptfs_parse_options
>   * @sb: The ecryptfs super block
> @@ -264,14 +266,13 @@ static int ecryptfs_parse_options(struct super_block *sb, char *options)
>  		case ecryptfs_opt_sig:
>  		case ecryptfs_opt_ecryptfs_sig:
>  			sig_src = args[0].from;
> -			sig_dst =
> -				mount_crypt_stat->global_auth_tok_sig;
> -			memcpy(sig_dst, sig_src, ECRYPTFS_SIG_SIZE_HEX);
> -			sig_dst[ECRYPTFS_SIG_SIZE_HEX] = '\0';
> -			ecryptfs_printk(KERN_DEBUG,
> -					"The mount_crypt_stat "
> -					"global_auth_tok_sig set to: "
> -					"[%s]\n", sig_dst);
> +			rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
> +							  sig_src);
> +			if (rc) {
> +				printk(KERN_ERR "Error attempting to register "
> +				       "global sig; rc = [%d]\n", rc);
> +				goto out;
> +			}
>  			sig_set = 1;
>  			break;
>  		case ecryptfs_opt_debug:
> @@ -358,55 +359,21 @@ static int ecryptfs_parse_options(struct super_block *sb, char *options)
>  	if (!cipher_key_bytes_set) {
>  		mount_crypt_stat->global_default_cipher_key_size = 0;
>  	}
> -	rc = ecryptfs_process_cipher(
> -		&mount_crypt_stat->global_key_tfm,
> -		mount_crypt_stat->global_default_cipher_name,
> -		&mount_crypt_stat->global_default_cipher_key_size);
> -	if (rc) {
> -		printk(KERN_ERR "Error attempting to initialize cipher [%s] "
> -		       "with key size [%Zd] bytes; rc = [%d]\n",
> +	if ((rc = ecryptfs_add_new_key_tfm(
> +		     NULL, mount_crypt_stat->global_default_cipher_name,
> +		     mount_crypt_stat->global_default_cipher_key_size))) {
> +		printk(KERN_ERR "Error attempting to initialize cipher with "
> +		       "name = [%s] and key size = [%d]; rc = [%d]\n",
>  		       mount_crypt_stat->global_default_cipher_name,
>  		       mount_crypt_stat->global_default_cipher_key_size, rc);
> -		mount_crypt_stat->global_key_tfm = NULL;
> -		mount_crypt_stat->global_auth_tok_key = NULL;
> -		rc = -EINVAL;
> -		goto out;
> -	}
> -	mutex_init(&mount_crypt_stat->global_key_tfm_mutex);
> -	ecryptfs_printk(KERN_DEBUG, "Requesting the key with description: "
> -			"[%s]\n", mount_crypt_stat->global_auth_tok_sig);
> -	/* The reference to this key is held until umount is done The
> -	 * call to key_put is done in ecryptfs_put_super() */
> -	auth_tok_key = request_key(&key_type_user,
> -				   mount_crypt_stat->global_auth_tok_sig,
> -				   NULL);
> -	if (!auth_tok_key || IS_ERR(auth_tok_key)) {
> -		ecryptfs_printk(KERN_ERR, "Could not find key with "
> -				"description: [%s]\n",
> -				mount_crypt_stat->global_auth_tok_sig);
> -		process_request_key_err(PTR_ERR(auth_tok_key));
>  		rc = -EINVAL;
>  		goto out;
>  	}
> -	auth_tok = ecryptfs_get_key_payload_data(auth_tok_key);
> -	if (ecryptfs_verify_version(auth_tok->version)) {
> -		ecryptfs_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) {
> -		ecryptfs_printk(KERN_ERR, "Invalid auth_tok structure "
> -				"returned from key query\n");
> -		rc = -EINVAL;
> -		goto out;
> +	if ((rc = ecryptfs_init_global_auth_toks(mount_crypt_stat))) {
> +		printk(KERN_WARNING "One or more global auth toks could not "
> +		       "properly register; rc = [%d]\n", rc);
>  	}
> -	mount_crypt_stat->global_auth_tok_key = auth_tok_key;
> -	mount_crypt_stat->global_auth_tok = auth_tok;
> +	rc = 0;
>  out:
>  	return rc;
>  }
> -- 
> 1.5.1.6
> 
> -
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