From c8cb714e086df31a55df75e044fb7d0200e6a0e7 Mon Sep 17 00:00:00 2001
From: Karel Miko <karel.miko@gmail.com>
Date: Wed, 29 Mar 2017 19:50:53 +0200
Subject: [PATCH] added chacha_done

---
 .../chachapoly/chacha20poly1305_done.c        |  1 +
 src/headers/tomcrypt_cipher.h                 |  1 +
 src/prngs/chacha.c                            |  7 ++---
 src/stream/chacha/chacha_done.c               | 31 +++++++++++++++++++
 4 files changed, 36 insertions(+), 4 deletions(-)
 create mode 100644 src/stream/chacha/chacha_done.c

diff --git a/src/encauth/chachapoly/chacha20poly1305_done.c b/src/encauth/chachapoly/chacha20poly1305_done.c
index fe25ab5..efe98b9 100644
--- a/src/encauth/chachapoly/chacha20poly1305_done.c
+++ b/src/encauth/chachapoly/chacha20poly1305_done.c
@@ -35,6 +35,7 @@ int chacha20poly1305_done(chachapoly_state *st, unsigned char *tag, unsigned lon
    STORE64L(st->ctlen, buf + 8);
    if ((err = poly1305_process(&st->poly, buf, 16)) != CRYPT_OK)           return err;
    if ((err = poly1305_done(&st->poly, tag, taglen)) != CRYPT_OK)          return err;
+   if ((err = chacha_done(&st->chacha)) != CRYPT_OK)                       return err;
    return CRYPT_OK;
 }
 
diff --git a/src/headers/tomcrypt_cipher.h b/src/headers/tomcrypt_cipher.h
index 36d0c0c..03cf80d 100644
--- a/src/headers/tomcrypt_cipher.h
+++ b/src/headers/tomcrypt_cipher.h
@@ -954,6 +954,7 @@ int chacha_ivctr32(chacha_state *st, const unsigned char *iv, unsigned long ivle
 int chacha_ivctr64(chacha_state *st, const unsigned char *iv, unsigned long ivlen, ulong64 counter);
 int chacha_crypt(chacha_state *st, const unsigned char *in, unsigned long inlen, unsigned char *out);
 int chacha_keystream(chacha_state *st, unsigned char *out, unsigned long outlen);
+int chacha_done(chacha_state *st);
 int chacha_test(void);
 
 #endif /* LTC_CHACHA */
diff --git a/src/prngs/chacha.c b/src/prngs/chacha.c
index 2d2d286..5a2ad55 100644
--- a/src/prngs/chacha.c
+++ b/src/prngs/chacha.c
@@ -103,6 +103,7 @@ int chacha_prng_ready(prng_state *prng)
 */
 unsigned long chacha_prng_read(unsigned char *out, unsigned long outlen, prng_state *prng)
 {
+   LTC_ARGCHK(prng != NULL);
    if (chacha_keystream(&prng->chacha.s, out, outlen) != CRYPT_OK) return 0;
    return outlen;
 }
@@ -114,10 +115,8 @@ unsigned long chacha_prng_read(unsigned char *out, unsigned long outlen, prng_st
 */
 int chacha_prng_done(prng_state *prng)
 {
-   LTC_UNUSED_PARAM(prng);
-   prng->chacha.ready = 0;
-   XMEMSET(&prng->chacha.s, 0, sizeof(chacha_state));
-   return CRYPT_OK;
+   LTC_ARGCHK(prng != NULL);
+   return chacha_done(&prng->chacha.s);
 }
 
 /**
diff --git a/src/stream/chacha/chacha_done.c b/src/stream/chacha/chacha_done.c
new file mode 100644
index 0000000..0fbff20
--- /dev/null
+++ b/src/stream/chacha/chacha_done.c
@@ -0,0 +1,31 @@
+/* LibTomCrypt, modular cryptographic library -- Tom St Denis
+ *
+ * LibTomCrypt is a library that provides various cryptographic
+ * algorithms in a highly modular and flexible manner.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ */
+
+/* The implementation is based on:
+ * chacha-ref.c version 20080118
+ * Public domain from D. J. Bernstein
+ */
+
+#include "tomcrypt.h"
+
+#ifdef LTC_CHACHA
+
+/**
+  Terminate and clear ChaCha state
+  @param st      The ChaCha state
+  @return CRYPT_OK on success
+*/
+int chacha_done(chacha_state *st)
+{
+   LTC_ARGCHK(st != NULL);
+   XMEMSET(st, 0, sizeof(chacha_state));
+   return CRYPT_OK;
+};
+
+#endif