From 87c94c4df0149786ad91d8a03c738a03369ee9c8 Mon Sep 17 00:00:00 2001 From: Michael Halcrow Date: Tue, 6 Jan 2009 14:42:01 -0800 Subject: eCryptfs: Filename Encryption: mount option Enable mount-wide filename encryption by providing the Filename Encryption Key (FNEK) signature as a mount option. Note that the ecryptfs-utils userspace package versions 61 or later support this option. When mounting with ecryptfs-utils version 61 or later, the mount helper will detect the availability of the passphrase-based filename encryption in the kernel (via the eCryptfs sysfs handle) and query the user interactively as to whether or not he wants to enable the feature for the mount. If the user enables filename encryption, the mount helper will then prompt for the FNEK signature that the user wishes to use, suggesting by default the signature for the mount passphrase that the user has already entered for encrypting the file contents. When not using the mount helper, the user can specify the signature for the passphrase key with the ecryptfs_fnek_sig= mount option. This key must be available in the user's keyring. The mount helper usually takes care of this step. If, however, the user is not mounting with the mount helper, then he will need to enter the passphrase key into his keyring with some other utility prior to mounting, such as ecryptfs-manager. Signed-off-by: Michael Halcrow Cc: Dustin Kirkland Cc: Eric Sandeen Cc: Tyler Hicks Cc: David Kleikamp Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ecryptfs/main.c | 126 +++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 99 insertions(+), 27 deletions(-) (limited to 'fs/ecryptfs') diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c index fd630713c5c..789cf2e1be1 100644 --- a/fs/ecryptfs/main.c +++ b/fs/ecryptfs/main.c @@ -206,7 +206,9 @@ enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig, ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher, ecryptfs_opt_ecryptfs_key_bytes, ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata, - ecryptfs_opt_encrypted_view, ecryptfs_opt_err }; + ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig, + ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes, + ecryptfs_opt_err }; static const match_table_t tokens = { {ecryptfs_opt_sig, "sig=%s"}, @@ -217,6 +219,9 @@ static const match_table_t tokens = { {ecryptfs_opt_passthrough, "ecryptfs_passthrough"}, {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"}, {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"}, + {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"}, + {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"}, + {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"}, {ecryptfs_opt_err, NULL} }; @@ -281,8 +286,11 @@ static int ecryptfs_parse_options(struct super_block *sb, char *options) int rc = 0; int sig_set = 0; int cipher_name_set = 0; + int fn_cipher_name_set = 0; int cipher_key_bytes; int cipher_key_bytes_set = 0; + int fn_cipher_key_bytes; + int fn_cipher_key_bytes_set = 0; struct ecryptfs_mount_crypt_stat *mount_crypt_stat = &ecryptfs_superblock_to_private(sb)->mount_crypt_stat; substring_t args[MAX_OPT_ARGS]; @@ -290,7 +298,12 @@ static int ecryptfs_parse_options(struct super_block *sb, char *options) char *sig_src; char *cipher_name_dst; char *cipher_name_src; + char *fn_cipher_name_dst; + char *fn_cipher_name_src; + char *fnek_dst; + char *fnek_src; char *cipher_key_bytes_src; + char *fn_cipher_key_bytes_src; if (!options) { rc = -EINVAL; @@ -322,10 +335,7 @@ static int ecryptfs_parse_options(struct super_block *sb, char *options) global_default_cipher_name; strncpy(cipher_name_dst, cipher_name_src, ECRYPTFS_MAX_CIPHER_NAME_SIZE); - ecryptfs_printk(KERN_DEBUG, - "The mount_crypt_stat " - "global_default_cipher_name set to: " - "[%s]\n", cipher_name_dst); + cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0'; cipher_name_set = 1; break; case ecryptfs_opt_ecryptfs_key_bytes: @@ -335,11 +345,6 @@ static int ecryptfs_parse_options(struct super_block *sb, char *options) &cipher_key_bytes_src, 0); mount_crypt_stat->global_default_cipher_key_size = cipher_key_bytes; - ecryptfs_printk(KERN_DEBUG, - "The mount_crypt_stat " - "global_default_cipher_key_size " - "set to: [%d]\n", mount_crypt_stat-> - global_default_cipher_key_size); cipher_key_bytes_set = 1; break; case ecryptfs_opt_passthrough: @@ -356,11 +361,51 @@ static int ecryptfs_parse_options(struct super_block *sb, char *options) mount_crypt_stat->flags |= ECRYPTFS_ENCRYPTED_VIEW_ENABLED; break; + case ecryptfs_opt_fnek_sig: + fnek_src = args[0].from; + fnek_dst = + mount_crypt_stat->global_default_fnek_sig; + strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX); + mount_crypt_stat->global_default_fnek_sig[ + ECRYPTFS_SIG_SIZE_HEX] = '\0'; + rc = ecryptfs_add_global_auth_tok( + mount_crypt_stat, + mount_crypt_stat->global_default_fnek_sig); + if (rc) { + printk(KERN_ERR "Error attempting to register " + "global fnek sig [%s]; rc = [%d]\n", + mount_crypt_stat->global_default_fnek_sig, + rc); + goto out; + } + mount_crypt_stat->flags |= + (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES + | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK); + break; + case ecryptfs_opt_fn_cipher: + fn_cipher_name_src = args[0].from; + fn_cipher_name_dst = + mount_crypt_stat->global_default_fn_cipher_name; + strncpy(fn_cipher_name_dst, fn_cipher_name_src, + ECRYPTFS_MAX_CIPHER_NAME_SIZE); + mount_crypt_stat->global_default_fn_cipher_name[ + ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0'; + fn_cipher_name_set = 1; + break; + case ecryptfs_opt_fn_cipher_key_bytes: + fn_cipher_key_bytes_src = args[0].from; + fn_cipher_key_bytes = + (int)simple_strtol(fn_cipher_key_bytes_src, + &fn_cipher_key_bytes_src, 0); + mount_crypt_stat->global_default_fn_cipher_key_bytes = + fn_cipher_key_bytes; + fn_cipher_key_bytes_set = 1; + break; case ecryptfs_opt_err: default: - ecryptfs_printk(KERN_WARNING, - "eCryptfs: unrecognized option '%s'\n", - p); + printk(KERN_WARNING + "%s: eCryptfs: unrecognized option [%s]\n", + __func__, p); } } if (!sig_set) { @@ -374,33 +419,60 @@ static int ecryptfs_parse_options(struct super_block *sb, char *options) int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER); BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE); - strcpy(mount_crypt_stat->global_default_cipher_name, ECRYPTFS_DEFAULT_CIPHER); } - if (!cipher_key_bytes_set) { + if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) + && !fn_cipher_name_set) + strcpy(mount_crypt_stat->global_default_fn_cipher_name, + mount_crypt_stat->global_default_cipher_name); + if (!cipher_key_bytes_set) mount_crypt_stat->global_default_cipher_key_size = 0; - } + if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) + && !fn_cipher_key_bytes_set) + mount_crypt_stat->global_default_fn_cipher_key_bytes = + mount_crypt_stat->global_default_cipher_key_size; mutex_lock(&key_tfm_list_mutex); if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name, - NULL)) + NULL)) { rc = ecryptfs_add_new_key_tfm( NULL, mount_crypt_stat->global_default_cipher_name, mount_crypt_stat->global_default_cipher_key_size); - mutex_unlock(&key_tfm_list_mutex); - if (rc) { - printk(KERN_ERR "Error attempting to initialize cipher with " - "name = [%s] and key size = [%td]; rc = [%d]\n", - mount_crypt_stat->global_default_cipher_name, - mount_crypt_stat->global_default_cipher_key_size, rc); - rc = -EINVAL; - goto out; + if (rc) { + printk(KERN_ERR "Error attempting to initialize " + "cipher with name = [%s] and key size = [%td]; " + "rc = [%d]\n", + mount_crypt_stat->global_default_cipher_name, + mount_crypt_stat->global_default_cipher_key_size, + rc); + rc = -EINVAL; + mutex_unlock(&key_tfm_list_mutex); + goto out; + } } + if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) + && !ecryptfs_tfm_exists( + mount_crypt_stat->global_default_fn_cipher_name, NULL)) { + rc = ecryptfs_add_new_key_tfm( + NULL, mount_crypt_stat->global_default_fn_cipher_name, + mount_crypt_stat->global_default_fn_cipher_key_bytes); + if (rc) { + printk(KERN_ERR "Error attempting to initialize " + "cipher with name = [%s] and key size = [%td]; " + "rc = [%d]\n", + mount_crypt_stat->global_default_fn_cipher_name, + mount_crypt_stat->global_default_fn_cipher_key_bytes, + rc); + rc = -EINVAL; + mutex_unlock(&key_tfm_list_mutex); + goto out; + } + } + mutex_unlock(&key_tfm_list_mutex); rc = ecryptfs_init_global_auth_toks(mount_crypt_stat); - if (rc) { + if (rc) printk(KERN_WARNING "One or more global auth toks could not " "properly register; rc = [%d]\n", rc); - } out: return rc; } -- cgit v1.2.3