crypto: picoxcell - don't leak pointers to authenc keys

In spacc_aead_setkey we save pointers to the authenc keys in a
local variable of type struct crypto_authenc_keys and we don't
zeroize it after use. Fix this and don't leak pointers to the
authenc keys.
Signed-off-by: NTudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: NJamie Iles <jamie@jamieiles.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/picoxcell_crypto.c

@@ -499,10 +499,12 @@ static int spacc_aead_setkey(struct crypto_aead *tfm, const u8 *key,
 	memcpy(ctx->hash_ctx, keys.authkey, keys.authkeylen);
 	ctx->hash_key_len = keys.authkeylen;
 
+	memzero_explicit(&keys, sizeof(keys));
 	return 0;
 
 badkey:
 	crypto_aead_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
+	memzero_explicit(&keys, sizeof(keys));
 	return -EINVAL;
 }