[PATCH 5/12] Packet and key management update for variable key size

From: Mike Halcrow
Date: Tue Jun 20 2006 - 17:22:50 EST


Modify packet and session key management code to support different key
sizes.

Signed-off-by: Michael Halcrow <mhalcrow@xxxxxxxxxx>

---

fs/ecryptfs/keystore.c | 21 +++++++++++----------
1 files changed, 11 insertions(+), 10 deletions(-)

9d85fe55c87fbfe9476f37078f05c40c1d1319ed
diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c
index 1a9917d..101773f 100644
--- a/fs/ecryptfs/keystore.c
+++ b/fs/ecryptfs/keystore.c
@@ -530,8 +530,6 @@ static int decrypt_session_key(struct ec
memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
auth_tok->session_key.decrypted_key_size);
ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_KEY_VALID);
- crypt_stat->key_size_bits =
- auth_tok->session_key.decrypted_key_size * 8;
ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
if (ecryptfs_verbosity > 0)
ecryptfs_dump_hex(crypt_stat->key,
@@ -810,11 +808,10 @@ write_tag_3_packet(char *dest, int max,
BUG();
ecryptfs_from_hex((*key_rec).sig, auth_tok->token.password.signature,
ECRYPTFS_SIG_SIZE);
- (*key_rec).enc_key_size_bits = crypt_stat->key_size_bits;
encrypted_session_key_valid = 0;
for (i = 0; i < (crypt_stat->key_size_bits / 8); i++)
encrypted_session_key_valid |=
- auth_tok->session_key.encrypted_key[i];
+ auth_tok->session_key.encrypted_key[i];
if (encrypted_session_key_valid) {
memcpy((*key_rec).enc_key,
auth_tok->session_key.encrypted_key,
@@ -824,6 +821,13 @@ write_tag_3_packet(char *dest, int max,
if (auth_tok->session_key.encrypted_key_size == 0)
auth_tok->session_key.encrypted_key_size =
(crypt_stat->key_size_bits / 8);
+ if (crypt_stat->key_size_bits == 192
+ && strcmp("aes", crypt_stat->cipher) == 0) {
+ memset((crypt_stat->key + 24), 0, 8);
+ auth_tok->session_key.encrypted_key_size = 32;
+ }
+ (*key_rec).enc_key_size_bits =
+ auth_tok->session_key.encrypted_key_size << 3;
if (ECRYPTFS_CHECK_FLAG(auth_tok->token.password.flags,
ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET)) {
ecryptfs_printk(KERN_DEBUG, "Using previously generated "
@@ -839,14 +843,11 @@ write_tag_3_packet(char *dest, int max,
ecryptfs_dump_hex(session_key_encryption_key, 16);
}
if (unlikely(ecryptfs_verbosity > 0)) {
- ecryptfs_printk(KERN_DEBUG, "Session key encryption key:"
- "\n");
+ ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
ecryptfs_dump_hex(session_key_encryption_key, 16);
}
- /* Encrypt the key with the key encryption key */
- /* Set up the scatterlists */
rc = virt_to_scatterlist(crypt_stat->key,
- crypt_stat->key_size_bits / 8, src_sg, 2);
+ (*key_rec).enc_key_size_bits / 8, src_sg, 2);
if (!rc) {
ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
"for crypt_stat session key\n");
@@ -879,7 +880,7 @@ write_tag_3_packet(char *dest, int max,
ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes of the key\n",
crypt_stat->key_size_bits / 8);
crypto_cipher_encrypt(tfm, dest_sg, src_sg,
- (crypt_stat->key_size_bits / 8));
+ (*key_rec).enc_key_size_bits / 8);
ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
if (ecryptfs_verbosity > 0)
ecryptfs_dump_hex((*key_rec).enc_key,
--
1.3.3

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