dm crypt: set key size early

Simplify key size verification (hexadecimal string) and
set key size early in constructor.

(Patch required by later changes.)

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 7 insertions, 6 deletions

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index d5b0e4c0e702..4c4408a2602f 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -973,15 +973,15 @@ static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
 
 static int crypt_set_key(struct crypt_config *cc, char *key)
 {
-        unsigned key_size = strlen(key) >> 1;
-
-        if (cc->key_size && cc->key_size != key_size)
+        /* The key size may not be changed. */
+        if (cc->key_size != (strlen(key) >> 1))
                 return -EINVAL;
 
-        cc->key_size = key_size; /* initial settings */
+        /* Hyphen (which gives a key_size of zero) means there is no key. */
+        if (!cc->key_size && strcmp(key, "-"))
+                return -EINVAL;
 
-        if ((!key_size && strcmp(key, "-")) ||
-           (key_size && crypt_decode_key(cc->key, key, key_size) < 0))
+        if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0)
                 return -EINVAL;
 
         set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
@@ -1194,6 +1194,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
                 ti->error = "Cannot allocate encryption context";
                 return -ENOMEM;
         }
+        cc->key_size = key_size;
 
         ti->private = cc;
         ret = crypt_ctr_cipher(ti, argv[0], argv[1]);