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eCryptfs: don't encrypt file key with filename key

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eCryptfs has file encryption keys (FEK), file encryption key encryption
keys (FEKEK), and filename encryption keys (FNEK).  The per-file FEK is
encrypted with one or more FEKEKs and stored in the header of the
encrypted file.  I noticed that the FEK is also being encrypted by the
FNEK.  This is a problem if a user wants to use a different FNEK than
their FEKEK, as their file contents will still be accessible with the
FNEK.

This is a minimalistic patch which prevents the FNEKs signatures from
being copied to the inode signatures list.  Ultimately, it keeps the FEK
from being encrypted with a FNEK.

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Acked-by: Dustin Kirkland <kirkland@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Tyler Hicks 2009-03-13 13:51:59 -07:00 committed by Linus Torvalds
parent 15e7b87676
commit 84814d642a
4 changed files with 9 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
fs/ecryptfs/crypto.c
View File

@ -946,6 +946,8 @@ static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
list_for_each_entry(global_auth_tok,
&mount_crypt_stat->global_auth_tok_list,
mount_crypt_stat_list) {
if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
continue;
rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
if (rc) {
printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);

3
fs/ecryptfs/ecryptfs_kernel.h
View File

@ -328,6 +328,7 @@ struct ecryptfs_dentry_info {
*/
struct ecryptfs_global_auth_tok {
#define ECRYPTFS_AUTH_TOK_INVALID 0x00000001
#define ECRYPTFS_AUTH_TOK_FNEK 0x00000002
u32 flags;
struct list_head mount_crypt_stat_list;
struct key *global_auth_tok_key;
@ -696,7 +697,7 @@ ecryptfs_write_header_metadata(char *virt,
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);
char *sig, u32 global_auth_tok_flags);
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);

3
fs/ecryptfs/keystore.c
View File

@ -2375,7 +2375,7 @@ struct kmem_cache *ecryptfs_global_auth_tok_cache;
int
ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
char *sig)
char *sig, u32 global_auth_tok_flags)
{
struct ecryptfs_global_auth_tok *new_auth_tok;
int rc = 0;
@ -2389,6 +2389,7 @@ ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
goto out;
}
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,

5
fs/ecryptfs/main.c
View File

@ -319,7 +319,7 @@ static int ecryptfs_parse_options(struct super_block *sb, char *options)
case ecryptfs_opt_ecryptfs_sig:
sig_src = args[0].from;
rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
sig_src);
sig_src, 0);
if (rc) {
printk(KERN_ERR "Error attempting to register "
"global sig; rc = [%d]\n", rc);
@ -370,7 +370,8 @@ static int ecryptfs_parse_options(struct super_block *sb, char *options)
ECRYPTFS_SIG_SIZE_HEX] = '\0';
rc = ecryptfs_add_global_auth_tok(
mount_crypt_stat,
mount_crypt_stat->global_default_fnek_sig);
mount_crypt_stat->global_default_fnek_sig,
ECRYPTFS_AUTH_TOK_FNEK);
if (rc) {
printk(KERN_ERR "Error attempting to register "
"global fnek sig [%s]; rc = [%d]\n",