File s390-tools-sles15sp2-32-zkey-Add-helper-function-to-check-an-AES-CIPHER-key.patch of Package s390-tools.15932
Subject: zkey: Add helper function to check an AES CIPHER key
From: Ingo Franzki <ifranzki@linux.ibm.com>
Summary: zkey: Add support for CCA AES CIPHER keys
Description: With CCA 5 there is a new secure key type, the so called
variable length symmetric cipher key token. This token format
can hold AES keys with size 128, 192 and 256 bits together
with additional attributes cryptographic bound to the key
token. The attributes may limit the usage of the key, for
example restrict export or usability scope. So this key type
is considered to be even more secure than the traditional
secure key token. This key token type is also called "CCA
AES CIPHER key", where the formerly used key token is called
"CCA AES DATA key".
The zkey as well as the zkey-cryptsetup tools are enhanced
to support AES CIPHER keys. That is, zkey can manage AES DATA
keys, as well as AES CIPHER keys. The key type must be specified
at key generation time, the default is to generate AED DATA
keys.
Upstream-ID: 7fede7021ece58b9960532e17d963f844fe0de02
Problem-ID: SEC1717
Upstream-Description:
zkey: Add helper function to check an AES CIPHER key
The helper function performs a deep check of the AES CIPHER key
token and checks for any potentially insecure attributes.
Signed-off-by: Ingo Franzki <ifranzki@linux.ibm.com>
Reviewed-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Signed-off-by: Ingo Franzki <ifranzki@linux.ibm.com>
---
zkey/pkey.c | 137 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
zkey/pkey.h | 1
2 files changed, 138 insertions(+)
--- a/zkey/pkey.c
+++ b/zkey/pkey.c
@@ -1650,3 +1650,140 @@ int get_min_card_level_for_keytype(const
return -1;
}
+
+/**
+ * Performs extended checks on an AES CIPHER key. It checks the key usage
+ * fields (KUFs) and key management fields (KMFs) of the key. The function
+ * returns -EINVAL and issues warning messages if a mismatch is detected.
+ *
+ * @param[in] key the secure key token
+ * @param[in] key_size the size of the secure key
+ *
+ * @returns 0 on success, a negative errno in case of an error
+ */
+int check_aes_cipher_key(const u8 *key, size_t key_size)
+{
+ struct aescipherkeytoken *cipherkey = (struct aescipherkeytoken *)key;
+ bool mismatch = false;
+
+ if (!is_cca_aes_cipher_key(key, key_size)) {
+ warnx("The key is not of type '"KEY_TYPE_CCA_AESCIPHER"'");
+ return -EINVAL;
+ }
+
+ if ((cipherkey->kuf1 & 0x8000) == 0) {
+ printf("WARNING: The secure key can not be used for "
+ "encryption\n");
+ mismatch = true;
+ }
+ if ((cipherkey->kuf1 & 0x4000) == 0) {
+ printf("WARNING: The secure key can not be used for "
+ "decryption\n");
+ mismatch = true;
+ }
+ if (cipherkey->kuf1 & 0x2000) {
+ printf("INFO: The secure key can be used for data translate\n");
+ mismatch = true;
+ }
+ if (cipherkey->kuf1 & 0x1000) {
+ printf("WARNING: The secure key can only be used in UDXs\n");
+ mismatch = true;
+ }
+
+ if (cipherkey->kmf1 & 0x8000) {
+ printf("WARNING: The secure key can be exported using a "
+ "symmetric key\n");
+ mismatch = true;
+ }
+ if (cipherkey->kmf1 & 0x4000) {
+ printf("WARNING: The secure key can be exported using an "
+ "unauthenticated asymmetric key\n");
+ mismatch = true;
+ }
+ if (cipherkey->kmf1 & 0x2000) {
+ printf("WARNING: The secure key can be exported using an "
+ "authenticated asymmetric key\n");
+ mismatch = true;
+ }
+ if (cipherkey->kmf1 & 0x1000) {
+ printf("WARNING: The secure key can be exported using a RAW "
+ "key\n");
+ mismatch = true;
+ }
+ if ((cipherkey->kmf1 & 0x0800) == 0) {
+ printf("WARNING: The secure key can not be transformed into a "
+ "CPACF protected key\n");
+ mismatch = true;
+ }
+ if ((cipherkey->kmf1 & 0x0080) == 0) {
+ printf("WARNING: The secure key can be exported using a DES "
+ "key\n");
+ mismatch = true;
+ }
+ if ((cipherkey->kmf1 & 0x0040) == 0) {
+ printf("WARNING: The secure key can be exported using an AES "
+ "key\n");
+ mismatch = true;
+ }
+ if ((cipherkey->kmf1 & 0x0008) == 0) {
+ printf("WARNING: The secure key can be exported using an RSA "
+ "key\n");
+ mismatch = true;
+ }
+
+ if (cipherkey->kmf2 & 0xC000) {
+ printf("WARNING: The secure key is incomplete\n");
+ mismatch = true;
+ }
+ if (cipherkey->kmf2 & 0x0010) {
+ printf("WARNING: The secure key was previously encrypted with "
+ "an untrusted KEK\n");
+ mismatch = true;
+ }
+ if (cipherkey->kmf2 & 0x0008) {
+ printf("WARNING: The secure key was previously in a format "
+ "without type or usage attributes\n");
+ mismatch = true;
+ }
+ if (cipherkey->kmf2 & 0x0004) {
+ printf("WARNING: The secure key was previously encrypted with "
+ "a key weaker than itself\n");
+ mismatch = true;
+ }
+ if (cipherkey->kmf2 & 0x0002) {
+ printf("WARNING: The secure key was previously in a non-CCA "
+ "format\n");
+ mismatch = true;
+ }
+ if (cipherkey->kmf2 & 0x0001) {
+ printf("WARNING: The secure key was previously encrypted in "
+ "ECB mode\n");
+ mismatch = true;
+ }
+
+ if ((cipherkey->kmf3 & 0xFF00) == 0x0000 ||
+ (cipherkey->kmf3 & 0x00FF) == 0x0000) {
+ printf("WARNING: The secure key was created by an unknown "
+ "method\n");
+ mismatch = true;
+ }
+ if ((cipherkey->kmf3 & 0xFF00) == 0x0400 ||
+ (cipherkey->kmf3 & 0x00FF) == 0x0004) {
+ printf("WARNING: The secure key was created from cleartext key "
+ "components\n");
+ mismatch = true;
+ }
+ if ((cipherkey->kmf3 & 0xFF00) == 0x0500 ||
+ (cipherkey->kmf3 & 0x00FF) == 0x0005) {
+ printf("WARNING: The secure key was entered as a cleartext key "
+ "value\n");
+ mismatch = true;
+ }
+ if ((cipherkey->kmf3 & 0x00FF) == 0x0012) {
+ printf("WARNING: The secure key was converted from a CCA "
+ "key-token that had no export control attributes\n");
+ mismatch = true;
+ }
+
+ return mismatch ? -EINVAL : 0;
+}
--- a/zkey/pkey.h
+++ b/zkey/pkey.h
@@ -265,5 +265,6 @@ bool is_xts_key(const u8 *key, size_t ke
int get_key_bit_size(const u8 *key, size_t key_size, size_t *bitsize);
const char *get_key_type(const u8 *key, size_t key_size);
int get_min_card_level_for_keytype(const char *key_type);
+int check_aes_cipher_key(const u8 *key, size_t key_size);
#endif
