Don't promise that passing NULL input to Blowfish works
It seems to work, but we don't test it currently,
so we shouldn't promise it.
diff --git a/include/mbedtls/blowfish.h b/include/mbedtls/blowfish.h
index 74d516d..cd53840 100644
--- a/include/mbedtls/blowfish.h
+++ b/include/mbedtls/blowfish.h
@@ -116,8 +116,10 @@
* \param mode The mode of operation. Possible values are
* #MBEDTLS_BLOWFISH_ENCRYPT for encryption, or
* #MBEDTLS_BLOWFISH_DECRYPT for decryption.
- * \param input The input block. This must be a readable buffer of size 8 Bytes.
- * \param input The output block. This must be a writable buffer of size 8 Bytes.
+ * \param input The input block. This must be a readable buffer
+ * of size \c 8 Bytes.
+ * \param output The output block. This must be a writable buffer
+ * of size \c 8 Bytes.
*
* \return \c 0 if successful.
* \return A negative error code on failure.
@@ -149,9 +151,9 @@
* \param iv The initialization vector. This must be a read/write buffer
* of length \c 8 Bytes. It is updated by this function.
* \param input The input data. This must be a readable buffer of length
- * \p length Bytes. If \p length if \c 0, it may be \c NULL.
+ * \p length Bytes.
* \param output The output data. This must be a writable buffer of length
- * \p length Bytes. If \p length if \c 0, it may be \c NULL.
+ * \p length Bytes.
*
* \return \c 0 if successful.
* \return A negative error code on failure.
@@ -186,12 +188,12 @@
* The value pointed to must be smaller than \c 8 Bytes.
* It is updated by this function to support the aforementioned
* streaming usage.
- * \param iv The initialization vector. This must be a read/write buffer of
- * size \c 8 Bytes. It is updated after use.
+ * \param iv The initialization vector. This must be a read/write buffer
+ * of size \c 8 Bytes. It is updated after use.
* \param input The input data. This must be a readable buffer of length
- * \p length Bytes. If \p length if \c 0, it may be \c NULL.
+ * \p length Bytes.
* \param output The output data. This must be a writable buffer of length
- * \p length Bytes. If \p length if \c 0, it may be \c NULL.
+ * \p length Bytes.
*
* \return \c 0 if successful.
* \return A negative error code on failure.
@@ -261,10 +263,10 @@
* read/write buffer of length \c 8 Bytes.
* \param stream_block The saved stream-block for resuming. This must point to
* a read/write buffer of length \c 8 Bytes.
- * \param input The input data. This must be a readable buffer of length
- * \p length Bytes. If \p length is \c 0, it may be \c NULL.
- * \param output The output data. This must be a writable buffer of length
- * \p length Bytes. If \p length is \c 0, it may be \c NULL.
+ * \param input The input data. This must be a readable buffer of
+ * length \p length Bytes.
+ * \param output The output data. This must be a writable buffer of
+ * length \p length Bytes.
*
* \return \c 0 if successful.
* \return A negative error code on failure.