eCryptfs: don't encrypt file key with filename key

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>

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 789cf2e1be1e..aed56c25539b 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -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",