Subject: [PATCH] [BZ 183875] zkey: Fix display of clear key size for CCA-AESCIPHER keys
From: Ingo Franzki <ifranzki@linux.ibm.com>

Description:   zkey: Fix display of clear key size for CCA-AESCIPHER keys
Symptom:       The 'zkey list' command shows bogus values for the
               keys 'Clear key size' for keys of type CCA-AESCIPHER.
Problem:       Secure keys of type CCA-AESCIPHER are variable length,
               dependent on the effective key size (e.g. 128, 192, or 256
               bits). However, the key blob stored is padded to a fixed 
               length, so that all key blobs of type CCA-AESCIPHER are
               the same size, regardless of the effective key bit size.
               To code to display the clear key bitsize does not correctly
               handle the padding and may treat a non-XTS key like an XTS
               key and thus reads past the end of the key blob. This 
               results in bogus values reported as clear key size.
               This bug has been introduced with feature SEC1717 "Cipher
               key support" with commit ddde3f354f35 ("zkey: Introduce th
               CCA-AESCIPHER key type").
Solution:      Correct the handling of key of type CCA-AESCIPHER.
Reproduction:  Generate a key of type CCA-AESCIPHER and then run 
               'zkey list'.
Upstream-ID:   49cbaba302f002aa7f148631a76fc21a3069bc25
Problem-ID:    183875

Upstream-Description:

              zkey: Fix display of clear key size for CCA-AESCIPHER keys

              Fixes: ddde3f354f35 ("zkey: Introduce the CCA-AESCIPHER key type")
              Signed-off-by: Ingo Franzki <ifranzki@linux.ibm.com>
              Signed-off-by: Jan Hoeppner <hoeppner@linux.ibm.com>


Signed-off-by: Ingo Franzki <ifranzki@linux.ibm.com>
--- a/zkey/pkey.c
+++ b/zkey/pkey.c
@@ -1600,9 +1600,9 @@ int get_key_bit_size(const u8 *key, size
 			*bitsize = cipherkey->pl - 384;
 		else
 			*bitsize = 0; /* Unknown */
-		if (key_size > cipherkey->length) {
+		if (key_size == 2 * AESCIPHER_KEY_SIZE) {
 			cipherkey = (struct aescipherkeytoken *)(key +
-					cipherkey->length);
+					AESCIPHER_KEY_SIZE);
 			if (cipherkey->pfv == 0x00) /* V0 payload */
 				*bitsize += cipherkey->pl - 384;
 		}