crypto: des - split off DES library from generic DES cipher driver

Another one for the cipher museum: split off DES core processing into
a separate module so other drivers (mostly for crypto accelerators)
can reuse the code without pulling in the generic DES cipher itself.
This will also permit the cipher interface to be made private to the
crypto API itself once we move the only user in the kernel (CIFS) to
this library interface.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 40 insertions, 29 deletions

diff --git a/include/crypto/internal/des.h b/include/crypto/internal/des.h
index f5d2e696522e..81ea1a425e9c 100644
--- a/include/crypto/internal/des.h
+++ b/include/crypto/internal/des.h
@@ -25,18 +25,21 @@
  */
 static inline int crypto_des_verify_key(struct crypto_tfm *tfm, const u8 *key)
 {
-	u32 tmp[DES_EXPKEY_WORDS];
-	int err = 0;
-
-	if (!(crypto_tfm_get_flags(tfm) & CRYPTO_TFM_REQ_FORBID_WEAK_KEYS))
-		return 0;
+	struct des_ctx tmp;
+	int err;
+
+	err = des_expand_key(&tmp, key, DES_KEY_SIZE);
+	if (err == -ENOKEY) {
+		if (crypto_tfm_get_flags(tfm) & CRYPTO_TFM_REQ_FORBID_WEAK_KEYS)
+			err = -EINVAL;
+		else
+			err = 0;
+	}
 
-	if (!des_ekey(tmp, key)) {
+	if (err)
 		crypto_tfm_set_flags(tfm, CRYPTO_TFM_RES_WEAK_KEY);
-		err = -EINVAL;
-	}
 
-	memzero_explicit(tmp, sizeof(tmp));
+	memzero_explicit(&tmp, sizeof(tmp));
 	return err;
 }
 
@@ -53,6 +56,28 @@ static inline int crypto_des_verify_key(struct crypto_tfm *tfm, const u8 *key)
  *   property.
  *
  */
+static inline int des3_ede_verify_key(const u8 *key, unsigned int key_len,
+				      bool check_weak)
+{
+	int ret = fips_enabled ? -EINVAL : -ENOKEY;
+	u32 K[6];
+
+	memcpy(K, key, DES3_EDE_KEY_SIZE);
+
+	if ((!((K[0] ^ K[2]) | (K[1] ^ K[3])) ||
+	     !((K[2] ^ K[4]) | (K[3] ^ K[5]))) &&
+	    (fips_enabled || check_weak))
+		goto bad;
+
+	if ((!((K[0] ^ K[4]) | (K[1] ^ K[5]))) && fips_enabled)
+		goto bad;
+
+	ret = 0;
+bad:
+	memzero_explicit(K, DES3_EDE_KEY_SIZE);
+
+	return ret;
+}
 
 /**
  * crypto_des3_ede_verify_key - Check whether a DES3-EDE key is weak
@@ -70,28 +95,14 @@ static inline int crypto_des_verify_key(struct crypto_tfm *tfm, const u8 *key)
 static inline int crypto_des3_ede_verify_key(struct crypto_tfm *tfm,
 					     const u8 *key)
 {
-	int err = -EINVAL;
-	u32 K[6];
-
-	memcpy(K, key, DES3_EDE_KEY_SIZE);
-
-	if ((!((K[0] ^ K[2]) | (K[1] ^ K[3])) ||
-	     !((K[2] ^ K[4]) | (K[3] ^ K[5]))) &&
-	    (fips_enabled || (crypto_tfm_get_flags(tfm) &
-		              CRYPTO_TFM_REQ_FORBID_WEAK_KEYS)))
-		goto bad;
-
-	if ((!((K[0] ^ K[4]) | (K[1] ^ K[5]))) && fips_enabled)
-		goto bad;
+	int err;
 
-	err = 0;
-out:
-	memzero_explicit(K, DES3_EDE_KEY_SIZE);
+	err = des3_ede_verify_key(key, DES3_EDE_KEY_SIZE,
+				  crypto_tfm_get_flags(tfm) &
+				  CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
+	if (err)
+		crypto_tfm_set_flags(tfm, CRYPTO_TFM_RES_WEAK_KEY);
 	return err;
-
-bad:
-	crypto_tfm_set_flags(tfm, CRYPTO_TFM_RES_WEAK_KEY);
-	goto out;
 }
 
 static inline int verify_skcipher_des_key(struct crypto_skcipher *tfm,