dm crypt: simplify crypt_ctr
Allocate cipher strings indpendently of struct crypt_config and move
cipher parsing and allocation into a separate function to prepare for
supporting the cryptoapi format e.g. "xts(aes)".
No functional change in this patch.
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 139bbe2..6401bfa 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -107,11 +107,10 @@
struct workqueue_struct *io_queue;
struct workqueue_struct *crypt_queue;
- /*
- * crypto related data
- */
+ char *cipher;
+ char *cipher_mode;
+
struct crypt_iv_operations *iv_gen_ops;
- char *iv_mode;
union {
struct iv_essiv_private essiv;
struct iv_benbi_private benbi;
@@ -135,8 +134,6 @@
unsigned int dmreq_start;
struct ablkcipher_request *req;
- char cipher[CRYPTO_MAX_ALG_NAME];
- char chainmode[CRYPTO_MAX_ALG_NAME];
struct crypto_ablkcipher *tfm;
unsigned long flags;
unsigned int key_size;
@@ -1032,90 +1029,102 @@
if (cc->dev)
dm_put_device(ti, cc->dev);
- kfree(cc->iv_mode);
+ kzfree(cc->cipher);
+ kzfree(cc->cipher_mode);
/* Must zero key material before freeing */
kzfree(cc);
}
-/*
- * Construct an encryption mapping:
- * <cipher> <key> <iv_offset> <dev_path> <start>
- */
-static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+static int crypt_ctr_cipher(struct dm_target *ti,
+ char *cipher_in, char *key)
{
- struct crypt_config *cc;
- char *tmp;
- char *cipher;
- char *chainmode;
- char *ivmode;
- char *ivopts;
- unsigned int key_size;
- unsigned long long tmpll;
+ struct crypt_config *cc = ti->private;
+ char *tmp, *cipher, *chainmode, *ivmode, *ivopts;
+ char *cipher_api = NULL;
int ret = -EINVAL;
- if (argc != 5) {
- ti->error = "Not enough arguments";
+ /* Convert to crypto api definition? */
+ if (strchr(cipher_in, '(')) {
+ ti->error = "Bad cipher specification";
return -EINVAL;
}
- tmp = argv[0];
+ /*
+ * Legacy dm-crypt cipher specification
+ * cipher-mode-iv:ivopts
+ */
+ tmp = cipher_in;
cipher = strsep(&tmp, "-");
+
+ cc->cipher = kstrdup(cipher, GFP_KERNEL);
+ if (!cc->cipher)
+ goto bad_mem;
+
+ if (tmp) {
+ cc->cipher_mode = kstrdup(tmp, GFP_KERNEL);
+ if (!cc->cipher_mode)
+ goto bad_mem;
+ }
+
chainmode = strsep(&tmp, "-");
ivopts = strsep(&tmp, "-");
ivmode = strsep(&ivopts, ":");
if (tmp)
- DMWARN("Unexpected additional cipher options");
+ DMWARN("Ignoring unexpected additional cipher options");
- key_size = strlen(argv[1]) >> 1;
-
- cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
- if (!cc) {
- ti->error = "Cannot allocate transparent encryption context";
- return -ENOMEM;
- }
-
- ti->private = cc;
-
- /* Compatibility mode for old dm-crypt cipher strings */
- if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) {
+ /* Compatibility mode for old dm-crypt mappings */
+ if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) {
+ kfree(cc->cipher_mode);
+ cc->cipher_mode = kstrdup("cbc-plain", GFP_KERNEL);
chainmode = "cbc";
ivmode = "plain";
}
if (strcmp(chainmode, "ecb") && !ivmode) {
- ti->error = "This chaining mode requires an IV mechanism";
- goto bad;
+ ti->error = "IV mechanism required";
+ return -EINVAL;
}
- ret = -ENOMEM;
- if (snprintf(cc->cipher, CRYPTO_MAX_ALG_NAME, "%s(%s)",
- chainmode, cipher) >= CRYPTO_MAX_ALG_NAME) {
- ti->error = "Chain mode + cipher name is too long";
- goto bad;
+ cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
+ if (!cipher_api)
+ goto bad_mem;
+
+ ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
+ "%s(%s)", chainmode, cipher);
+ if (ret < 0) {
+ kfree(cipher_api);
+ goto bad_mem;
}
- cc->tfm = crypto_alloc_ablkcipher(cc->cipher, 0, 0);
+ /* Allocate cipher */
+ cc->tfm = crypto_alloc_ablkcipher(cipher_api, 0, 0);
if (IS_ERR(cc->tfm)) {
+ ret = PTR_ERR(cc->tfm);
ti->error = "Error allocating crypto tfm";
goto bad;
}
- strcpy(cc->cipher, cipher);
- strcpy(cc->chainmode, chainmode);
-
- ret = crypt_set_key(cc, argv[1]);
+ /* Initialize and set key */
+ ret = crypt_set_key(cc, key);
if (ret < 0) {
ti->error = "Error decoding and setting key";
goto bad;
}
- /*
- * Choose ivmode. Valid modes: "plain", "essiv:<esshash>", "benbi".
- * See comments at iv code
- */
- ret = -EINVAL;
+ /* Initialize IV */
+ cc->iv_size = crypto_ablkcipher_ivsize(cc->tfm);
+ if (cc->iv_size)
+ /* at least a 64 bit sector number should fit in our buffer */
+ cc->iv_size = max(cc->iv_size,
+ (unsigned int)(sizeof(u64) / sizeof(u8)));
+ else if (ivmode) {
+ DMWARN("Selected cipher does not support IVs");
+ ivmode = NULL;
+ }
+
+ /* Choose ivmode, see comments at iv code. */
if (ivmode == NULL)
cc->iv_gen_ops = NULL;
else if (strcmp(ivmode, "plain") == 0)
@@ -1129,6 +1138,7 @@
else if (strcmp(ivmode, "null") == 0)
cc->iv_gen_ops = &crypt_iv_null_ops;
else {
+ ret = -EINVAL;
ti->error = "Invalid IV mode";
goto bad;
}
@@ -1151,20 +1161,45 @@
}
}
- cc->iv_size = crypto_ablkcipher_ivsize(cc->tfm);
- if (cc->iv_size)
- /* at least a 64 bit sector number should fit in our buffer */
- cc->iv_size = max(cc->iv_size,
- (unsigned int)(sizeof(u64) / sizeof(u8)));
- else {
- if (cc->iv_gen_ops) {
- DMWARN("Selected cipher does not support IVs");
- if (cc->iv_gen_ops->dtr)
- cc->iv_gen_ops->dtr(cc);
- cc->iv_gen_ops = NULL;
- }
+ ret = 0;
+bad:
+ kfree(cipher_api);
+ return ret;
+
+bad_mem:
+ ti->error = "Cannot allocate cipher strings";
+ return -ENOMEM;
+}
+
+/*
+ * Construct an encryption mapping:
+ * <cipher> <key> <iv_offset> <dev_path> <start>
+ */
+static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+ struct crypt_config *cc;
+ unsigned int key_size;
+ unsigned long long tmpll;
+ int ret;
+
+ if (argc != 5) {
+ ti->error = "Not enough arguments";
+ return -EINVAL;
}
+ key_size = strlen(argv[1]) >> 1;
+
+ cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
+ if (!cc) {
+ ti->error = "Cannot allocate encryption context";
+ return -ENOMEM;
+ }
+
+ ti->private = cc;
+ ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
+ if (ret < 0)
+ goto bad;
+
ret = -ENOMEM;
cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
if (!cc->io_pool) {
@@ -1217,17 +1252,6 @@
cc->start = tmpll;
ret = -ENOMEM;
- if (ivmode && cc->iv_gen_ops) {
- if (ivopts)
- *(ivopts - 1) = ':';
- cc->iv_mode = kstrdup(ivmode, GFP_KERNEL);
- if (!cc->iv_mode) {
- ti->error = "Error kmallocing iv_mode string";
- goto bad;
- }
- } else
- cc->iv_mode = NULL;
-
cc->io_queue = create_singlethread_workqueue("kcryptd_io");
if (!cc->io_queue) {
ti->error = "Couldn't create kcryptd io queue";
@@ -1273,7 +1297,7 @@
static int crypt_status(struct dm_target *ti, status_type_t type,
char *result, unsigned int maxlen)
{
- struct crypt_config *cc = (struct crypt_config *) ti->private;
+ struct crypt_config *cc = ti->private;
unsigned int sz = 0;
switch (type) {
@@ -1282,11 +1306,10 @@
break;
case STATUSTYPE_TABLE:
- if (cc->iv_mode)
- DMEMIT("%s-%s-%s ", cc->cipher, cc->chainmode,
- cc->iv_mode);
+ if (cc->cipher_mode)
+ DMEMIT("%s-%s ", cc->cipher, cc->cipher_mode);
else
- DMEMIT("%s-%s ", cc->cipher, cc->chainmode);
+ DMEMIT("%s ", cc->cipher);
if (cc->key_size > 0) {
if ((maxlen - sz) < ((cc->key_size << 1) + 1))