From 87d450793780e9da74016277272b3a5b521f80ab Mon Sep 17 00:00:00 2001
From: Vsevolod Stakhov <vsevolod@highsecure.ru>
Date: Fri, 6 Feb 2015 17:15:32 +0000
Subject: [PATCH] Implement verification and keypair generation.

---
 src/libcryptobox/chacha20/ref.c |  3 +-
 src/libcryptobox/cryptobox.c    | 50 +++++++++++++++++++++++++++++++++
 src/libcryptobox/cryptobox.h    | 11 ++++++--
 3 files changed, 59 insertions(+), 5 deletions(-)

diff --git a/src/libcryptobox/chacha20/ref.c b/src/libcryptobox/chacha20/ref.c
index bd6a44a82..905e76c83 100644
--- a/src/libcryptobox/chacha20/ref.c
+++ b/src/libcryptobox/chacha20/ref.c
@@ -228,8 +228,7 @@ hchacha_ref(const unsigned char key[32], const unsigned char iv[16], unsigned ch
 
 void
 chacha_clear_state_ref(chacha_state_internal *state) {
-	void * (* volatile safe_memset)(void *s, int c, size_t n) = memset;
-	safe_memset(state, 0, 48);
+	rspamd_explicit_memzero (state, 48);
 }
 
 void
diff --git a/src/libcryptobox/cryptobox.c b/src/libcryptobox/cryptobox.c
index e96f4ec09..aee25c803 100644
--- a/src/libcryptobox/cryptobox.c
+++ b/src/libcryptobox/cryptobox.c
@@ -29,6 +29,12 @@
 
 unsigned long cpu_config = 0;
 
+static const rspamd_nonce_t n0 = {0};
+static const unsigned char sigma[16] = {
+		'e', 'x', 'p', 'a', 'n', 'd', ' ', '3', '2',
+		'-', 'b', 'y', 't', 'e', ' ', 'k'
+};
+
 #ifdef HAVE_WEAK_SYMBOLS
 __attribute__((weak)) void
 _dummy_symbol_to_prevent_lto(void * const pnt, const size_t len)
@@ -102,3 +108,47 @@ rspamd_cryptobox_init (void)
 
 	chacha_load ();
 }
+
+void
+rspamd_cryptobox_keypair (rspamd_pk_t pk, rspamd_sk_t sk)
+{
+	ottery_rand_bytes (sk, rspamd_cryptobox_SKBYTES);
+	sk[0] &= 248;
+	sk[31] &= 127;
+	sk[31] |= 64;
+
+	curve25519 (pk, sk, curve25519_basepoint);
+}
+
+void
+rspamd_cryptobox_nm (rspamd_nm_t nm, rspamd_pk_t pk, rspamd_sk_t sk)
+{
+	guchar s[rspamd_cryptobox_PKBYTES];
+
+	curve25519 (s, sk, pk);
+	hchacha (s, sigma, nm, 20);
+}
+
+gboolean
+rspamd_cryptobox_decrypt_nm_inplace (guchar *data, gsize len,
+		const rspamd_nonce_t nonce, const rspamd_nm_t nm, const rspamd_sig_t sig)
+{
+	poly1305_context mac_ctx;
+	guchar subkey[32];
+	rspamd_sig_t mac;
+
+	/* Generate MAC key */
+	memset (subkey, 0, sizeof (subkey));
+	xchacha (nm, nonce, subkey, subkey, sizeof (subkey), 20);
+
+	poly1305_init (&mac_ctx, subkey);
+	poly1305_update (&mac_ctx, data, len);
+	poly1305_finish (&mac_ctx, mac);
+
+	if (!poly1305_verify (mac, sig)) {
+		return FALSE;
+	}
+
+
+	return TRUE;
+}
diff --git a/src/libcryptobox/cryptobox.h b/src/libcryptobox/cryptobox.h
index 565371b70..f0df9a188 100644
--- a/src/libcryptobox/cryptobox.h
+++ b/src/libcryptobox/cryptobox.h
@@ -35,6 +35,7 @@ typedef guchar rspamd_pk_t[rspamd_cryptobox_PKBYTES];
 typedef guchar rspamd_sk_t[rspamd_cryptobox_SKBYTES];
 typedef guchar rspamd_sig_t[rspamd_cryptobox_MACBYTES];
 typedef guchar rspamd_nm_t[rspamd_cryptobox_NMBYTES];
+typedef guchar rspamd_nonce_t[rspamd_cryptobox_NONCEBYTES];
 
 /**
  * Init cryptobox library
@@ -57,7 +58,8 @@ void rspamd_cryptobox_keypair (rspamd_pk_t pk, rspamd_sk_t sk);
  * @param sig output signature
  */
 void rspamd_cryptobox_encrypt_inplace (guchar *data, gsize len,
-		gsize cnt, const rspamd_pk_t pk, const rspamd_sk_t sk, rspamd_sig_t sig);
+		const rspamd_nonce_t nonce,
+		const rspamd_pk_t pk, const rspamd_sk_t sk, rspamd_sig_t sig);
 
 
 /**
@@ -70,7 +72,8 @@ void rspamd_cryptobox_encrypt_inplace (guchar *data, gsize len,
  * @return TRUE if input has been verified successfully
  */
 gboolean rspamd_cryptobox_decrypt_inplace (guchar *data, gsize len,
-		 const rspamd_pk_t pk, const rspamd_sk_t sk, const rspamd_sig_t sig);
+		const rspamd_nonce_t nonce,
+		const rspamd_pk_t pk, const rspamd_sk_t sk, const rspamd_sig_t sig);
 
 /**
  * Encrypt segments of data inplace adding signature to sig afterwards
@@ -81,7 +84,8 @@ gboolean rspamd_cryptobox_decrypt_inplace (guchar *data, gsize len,
  * @param sig output signature
  */
 void rspamd_cryptobox_encrypt_nm_inplace (guchar *data, gsize len,
-		gsize cnt, const rspamd_nm_t nm, rspamd_sig_t sig);
+		const rspamd_nonce_t nonce,
+		const rspamd_nm_t nm, rspamd_sig_t sig);
 
 
 /**
@@ -94,6 +98,7 @@ void rspamd_cryptobox_encrypt_nm_inplace (guchar *data, gsize len,
  * @return TRUE if input has been verified successfully
  */
 gboolean rspamd_cryptobox_decrypt_nm_inplace (guchar *data, gsize len,
+		 const rspamd_nonce_t nonce,
 		 const rspamd_nm_t nm, const rspamd_sig_t sig);
 
 /**
-- 
2.39.5