crypto: clarify name of WEAK_KEY request flag

CRYPTO_TFM_REQ_WEAK_KEY confuses newcomers to the crypto API because it
sounds like it is requesting a weak key.  Actually, it is requesting
that weak keys be forbidden (for algorithms that have the notion of
"weak keys"; currently only DES and XTS do).

Also it is only one letter away from CRYPTO_TFM_RES_WEAK_KEY, with which
it can be easily confused.  (This in fact happened in the UX500 driver,
though just in some debugging messages.)

Therefore, make the intent clear by renaming it to
CRYPTO_TFM_REQ_FORBID_WEAK_KEYS.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

fs/crypto/keyinfo.c

@@ -47,7 +47,7 @@ static int derive_key_aes(const u8 *master_key,
 		tfm = NULL;
 		goto out;
 	}
-	crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_WEAK_KEY);
+	crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
 	req = skcipher_request_alloc(tfm, GFP_NOFS);
 	if (!req) {
 		res = -ENOMEM;
@@ -257,7 +257,7 @@ allocate_skcipher_for_mode(struct fscrypt_mode *mode, const u8 *raw_key,
 			mode->friendly_name,
 			crypto_skcipher_alg(tfm)->base.cra_driver_name);
 	}
-	crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_WEAK_KEY);
+	crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
 	err = crypto_skcipher_setkey(tfm, raw_key, mode->keysize);
 	if (err)
 		goto err_free_tfm;

fs/ecryptfs/crypto.c

@@ -610,7 +610,8 @@ int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
 				full_alg_name);
 		goto out_free;
 	}
-	crypto_skcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
+	crypto_skcipher_set_flags(crypt_stat->tfm,
+				  CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
 	rc = 0;
 out_free:
 	kfree(full_alg_name);
@@ -1590,7 +1591,7 @@ ecryptfs_process_key_cipher(struct crypto_skcipher **key_tfm,
 		       "[%s]; rc = [%d]\n", full_alg_name, rc);
 		goto out;
 	}
-	crypto_skcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
+	crypto_skcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
 	if (*key_size == 0)
 		*key_size = crypto_skcipher_default_keysize(*key_tfm);
 	get_random_bytes(dummy_key, *key_size);