[PATCH 1/6] eCryptfs: Clean up crypto initialization

Michael Halcrow
2006-10-30T23:33:18Z

Clean up the crypto initialization code; let the crypto API take care
of the key size checks.

Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>

---

fs/ecryptfs/crypto.c | 66 +++++++----------------------------------
fs/ecryptfs/ecryptfs_kernel.h | 4 +-
fs/ecryptfs/keystore.c | 19 +++++-------
fs/ecryptfs/main.c | 13 +-------
4 files changed, 24 insertions(+), 78 deletions(-)

4a2f411a7a2449b5dd09e5b9688dbd76e7b2b280
diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index ed35a97..82e7d02 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1573,35 +1573,26 @@ out:

/**
* ecryptfs_process_cipher - Perform cipher initialization.
- * @tfm: Crypto context set by this function
* @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.
+ * @cipher_name: Name of the cipher
+ * @key_size: Size of the key in bytes
*
* Returns zero on success. Any crypto_tfm structs allocated here
* should be released by other functions, such as on a superblock put
* event, regardless of whether this function succeeds for fails.
*/
int
-ecryptfs_process_cipher(struct crypto_tfm **tfm, struct crypto_tfm **key_tfm,
- char *cipher_name, size_t key_size)
+ecryptfs_process_cipher(struct crypto_tfm **key_tfm, char *cipher_name,
+ size_t *key_size)
{
char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
int rc;

- *tfm = *key_tfm = NULL;
- if (key_size > ECRYPTFS_MAX_KEY_BYTES) {
+ *key_tfm = NULL;
+ if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
rc = -EINVAL;
printk(KERN_ERR "Requested key size is [%Zd] bytes; maximum "
- "allowable is [%d]\n", key_size, ECRYPTFS_MAX_KEY_BYTES);
- goto out;
- }
- *tfm = crypto_alloc_tfm(cipher_name, (ECRYPTFS_DEFAULT_CHAINING_MODE
- | CRYPTO_TFM_REQ_WEAK_KEY));
- if (!(*tfm)) {
- rc = -EINVAL;
- printk(KERN_ERR "Unable to allocate crypto cipher with name "
- "[%s]\n", cipher_name);
+ "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
goto out;
}
*key_tfm = crypto_alloc_tfm(cipher_name, CRYPTO_TFM_REQ_WEAK_KEY);
@@ -1611,46 +1602,13 @@ ecryptfs_process_cipher(struct crypto_tf
"[%s]\n", cipher_name);
goto out;
}
- if (key_size < crypto_tfm_alg_min_keysize(*tfm)) {
- rc = -EINVAL;
- printk(KERN_ERR "Request key size is [%Zd]; minimum key size "
- "supported by cipher [%s] is [%d]\n", key_size,
- cipher_name, crypto_tfm_alg_min_keysize(*tfm));
- goto out;
- }
- if (key_size < crypto_tfm_alg_min_keysize(*key_tfm)) {
- rc = -EINVAL;
- printk(KERN_ERR "Request key size is [%Zd]; minimum key size "
- "supported by cipher [%s] is [%d]\n", key_size,
- cipher_name, crypto_tfm_alg_min_keysize(*key_tfm));
- goto out;
- }
- if (key_size > crypto_tfm_alg_max_keysize(*tfm)) {
- rc = -EINVAL;
- printk(KERN_ERR "Request key size is [%Zd]; maximum key size "
- "supported by cipher [%s] is [%d]\n", key_size,
- cipher_name, crypto_tfm_alg_min_keysize(*tfm));
- goto out;
- }
- if (key_size > crypto_tfm_alg_max_keysize(*key_tfm)) {
- rc = -EINVAL;
- printk(KERN_ERR "Request key size is [%Zd]; maximum key size "
- "supported by cipher [%s] is [%d]\n", key_size,
- cipher_name, crypto_tfm_alg_min_keysize(*key_tfm));
- goto out;
- }
- get_random_bytes(dummy_key, key_size);
- rc = crypto_cipher_setkey(*tfm, dummy_key, key_size);
- if (rc) {
- printk(KERN_ERR "Error attempting to set key of size [%Zd] for "
- "cipher [%s]; rc = [%d]\n", key_size, cipher_name, rc);
- rc = -EINVAL;
- goto out;
- }
- rc = crypto_cipher_setkey(*key_tfm, dummy_key, key_size);
+ if (*key_size == 0)
+ *key_size = crypto_tfm_alg_max_keysize(*key_tfm);
+ get_random_bytes(dummy_key, *key_size);
+ rc = crypto_cipher_setkey(*key_tfm, dummy_key, *key_size);
if (rc) {
printk(KERN_ERR "Error attempting to set key of size [%Zd] for "
- "cipher [%s]; rc = [%d]\n", key_size, cipher_name, rc);
+ "cipher [%s]; rc = [%d]\n", *key_size, cipher_name, rc);
rc = -EINVAL;
goto out;
}
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 872c995..4112df9 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -473,8 +473,8 @@ ecryptfs_parse_packet_set(struct ecryptf
unsigned char *src, struct dentry *ecryptfs_dentry);
int ecryptfs_truncate(struct dentry *dentry, loff_t new_length);
int
-ecryptfs_process_cipher(struct crypto_tfm **tfm, struct crypto_tfm **key_tfm,
- char *cipher_name, size_t key_size);
+ecryptfs_process_cipher(struct crypto_tfm **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);
diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c
index ba45478..bc706d3 100644
--- a/fs/ecryptfs/keystore.c
+++ b/fs/ecryptfs/keystore.c
@@ -493,19 +493,16 @@ static int decrypt_session_key(struct ec
goto out;
}
}
- if (password_s_ptr->session_key_encryption_key_bytes
- < crypto_tfm_alg_min_keysize(tfm)) {
- printk(KERN_WARNING "Session key encryption key is [%d] bytes; "
- "minimum keysize for selected cipher is [%d] bytes.\n",
- password_s_ptr->session_key_encryption_key_bytes,
- crypto_tfm_alg_min_keysize(tfm));
- rc = -EINVAL;
- goto out;
- }
if (tfm_mutex)
mutex_lock(tfm_mutex);
- crypto_cipher_setkey(tfm, password_s_ptr->session_key_encryption_key,
- crypt_stat->key_size);
+ rc = crypto_cipher_setkey(tfm,
+ password_s_ptr->session_key_encryption_key,
+ crypt_stat->key_size);
+ if (rc < 0) {
+ 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) {
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 5938a23..a65f486 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -208,7 +208,6 @@ static int ecryptfs_parse_options(struct
char *cipher_name_dst;
char *cipher_name_src;
char *cipher_key_bytes_src;
- struct crypto_tfm *tmp_tfm;
int cipher_name_len;

if (!options) {
@@ -305,20 +304,12 @@ static int ecryptfs_parse_options(struct
= '\0';
}
if (!cipher_key_bytes_set) {
- mount_crypt_stat->global_default_cipher_key_size =
- ECRYPTFS_DEFAULT_KEY_BYTES;
- ecryptfs_printk(KERN_DEBUG, "Cipher key size was not "
- "specified. Defaulting to [%d]\n",
- mount_crypt_stat->
- global_default_cipher_key_size);
+ mount_crypt_stat->global_default_cipher_key_size = 0;
}
rc = ecryptfs_process_cipher(
- &tmp_tfm,
&mount_crypt_stat->global_key_tfm,
mount_crypt_stat->global_default_cipher_name,
- mount_crypt_stat->global_default_cipher_key_size);
- if (tmp_tfm)
- crypto_free_tfm(tmp_tfm);
+ &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",
--
1.3.3