Add a ChaCha20-Poly1305 AEAD EVP implementation to libcrypto, from Adam

Langley's Chromium OpenSSL patches.

ok miod@

3 files changed, 272 insertions, 0 deletions

diff --git a/lib/libcrypto/evp/e_chacha20poly1305.c b/lib/libcrypto/evp/e_chacha20poly1305.c
new file mode 100644
index 00000000000..9df6b7c453f
--- /dev/null
+++ b/lib/libcrypto/evp/e_chacha20poly1305.c
@@ -0,0 +1,261 @@
+/* ====================================================================
+ * Copyright (c) 2013 The OpenSSL Project.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer. 
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. All advertising materials mentioning features or use of this
+ *    software must display the following acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ *    endorse or promote products derived from this software without
+ *    prior written permission. For written permission, please contact
+ *    openssl-core@openssl.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ *    nor may "OpenSSL" appear in their names without prior written
+ *    permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ *    acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ * ====================================================================
+ *
+ */
+
+#include <stdint.h>
+#include <string.h>
+#include <openssl/opensslconf.h>
+
+#if !defined(OPENSSL_NO_CHACHA) && !defined(OPENSSL_NO_POLY1305)
+
+#include <openssl/chacha.h>
+#include <openssl/poly1305.h>
+#include <openssl/evp.h>
+#include <openssl/err.h>
+#include "evp_locl.h"
+
+#define POLY1305_TAG_LEN 16
+#define CHACHA20_NONCE_LEN 8
+
+struct aead_chacha20_poly1305_ctx
+	{
+	unsigned char key[32];
+	unsigned char tag_len;
+	};
+
+static int aead_chacha20_poly1305_init(EVP_AEAD_CTX *ctx, const unsigned char *key, size_t key_len, size_t tag_len)
+	{
+	struct aead_chacha20_poly1305_ctx *c20_ctx;
+
+	if (tag_len == 0)
+		tag_len = POLY1305_TAG_LEN;
+
+	if (tag_len > POLY1305_TAG_LEN)
+		{
+		EVPerr(EVP_F_AEAD_CHACHA20_POLY1305_INIT, EVP_R_TOO_LARGE);
+		return 0;
+		}
+
+	if (key_len != sizeof(c20_ctx->key))
+		return 0;  /* internal error - EVP_AEAD_CTX_init should catch this. */
+
+	c20_ctx = OPENSSL_malloc(sizeof(struct aead_chacha20_poly1305_ctx));
+	if (c20_ctx == NULL)
+		return 0;
+
+	memcpy(&c20_ctx->key[0], key, key_len);
+	c20_ctx->tag_len = tag_len;
+	ctx->aead_state = c20_ctx;
+
+	return 1;
+	}
+
+static void aead_chacha20_poly1305_cleanup(EVP_AEAD_CTX *ctx)
+	{
+	struct aead_chacha20_poly1305_ctx *c20_ctx = ctx->aead_state;
+	OPENSSL_cleanse(c20_ctx->key, sizeof(c20_ctx->key));
+	OPENSSL_free(c20_ctx);
+	}
+
+static void poly1305_update_with_length(poly1305_state *poly1305,
+	const unsigned char *data, size_t data_len)
+	{
+	size_t j = data_len;
+	unsigned char length_bytes[8];
+	unsigned i;
+
+	for (i = 0; i < sizeof(length_bytes); i++)
+		{
+		length_bytes[i] = j;
+		j >>= 8;
+		}
+
+	CRYPTO_poly1305_update(poly1305, data, data_len);
+	CRYPTO_poly1305_update(poly1305, length_bytes, sizeof(length_bytes));
+}
+
+static ssize_t aead_chacha20_poly1305_seal(const EVP_AEAD_CTX *ctx,
+	unsigned char *out, size_t max_out_len,
+	const unsigned char *nonce, size_t nonce_len,
+	const unsigned char *in, size_t in_len,
+	const unsigned char *ad, size_t ad_len)
+	{
+	const struct aead_chacha20_poly1305_ctx *c20_ctx = ctx->aead_state;
+	unsigned char poly1305_key[32];
+	poly1305_state poly1305;
+	const uint64_t in_len_64 = in_len;
+
+	/* The underlying ChaCha implementation may not overflow the block
+	 * counter into the second counter word. Therefore we disallow
+	 * individual operations that work on more than 2TB at a time.
+	 * in_len_64 is needed because, on 32-bit platforms, size_t is only
+	 * 32-bits and this produces a warning because it's always false.
+	 * Casting to uint64_t inside the conditional is not sufficient to stop
+	 * the warning. */
+	if (in_len_64 >= (1ull << 32)*64-64)
+		{
+		EVPerr(EVP_F_AEAD_CHACHA20_POLY1305_SEAL, EVP_R_TOO_LARGE);
+		return -1;
+		}
+
+	if (max_out_len < in_len + c20_ctx->tag_len)
+		{
+		EVPerr(EVP_F_AEAD_CHACHA20_POLY1305_SEAL, EVP_R_BUFFER_TOO_SMALL);
+		return -1;
+		}
+
+	if (nonce_len != CHACHA20_NONCE_LEN)
+		{
+		EVPerr(EVP_F_AEAD_CHACHA20_POLY1305_SEAL, EVP_R_IV_TOO_LARGE);
+		return -1;
+		}
+
+	memset(poly1305_key, 0, sizeof(poly1305_key));
+	CRYPTO_chacha_20(poly1305_key, poly1305_key, sizeof(poly1305_key), c20_ctx->key, nonce, 0);
+
+	CRYPTO_poly1305_init(&poly1305, poly1305_key);
+	poly1305_update_with_length(&poly1305, ad, ad_len);
+	CRYPTO_chacha_20(out, in, in_len, c20_ctx->key, nonce, 1);
+	poly1305_update_with_length(&poly1305, out, in_len);
+
+	if (c20_ctx->tag_len != POLY1305_TAG_LEN)
+		{
+		unsigned char tag[POLY1305_TAG_LEN];
+		CRYPTO_poly1305_finish(&poly1305, tag);
+		memcpy(out + in_len, tag, c20_ctx->tag_len);
+		return in_len + c20_ctx->tag_len;
+		}
+
+	CRYPTO_poly1305_finish(&poly1305, out + in_len);
+	return in_len + POLY1305_TAG_LEN;
+	}
+
+static ssize_t aead_chacha20_poly1305_open(const EVP_AEAD_CTX *ctx,
+	unsigned char *out, size_t max_out_len,
+	const unsigned char *nonce, size_t nonce_len,
+	const unsigned char *in, size_t in_len,
+	const unsigned char *ad, size_t ad_len)
+	{
+	const struct aead_chacha20_poly1305_ctx *c20_ctx = ctx->aead_state;
+	unsigned char mac[POLY1305_TAG_LEN];
+	unsigned char poly1305_key[32];
+	size_t out_len;
+	poly1305_state poly1305;
+	const uint64_t in_len_64 = in_len;
+
+	if (in_len < c20_ctx->tag_len)
+		{
+		EVPerr(EVP_F_AEAD_CHACHA20_POLY1305_OPEN, EVP_R_BAD_DECRYPT);
+		return -1;
+		}
+
+	/* The underlying ChaCha implementation may not overflow the block
+	 * counter into the second counter word. Therefore we disallow
+	 * individual operations that work on more than 2TB at a time.
+	 * in_len_64 is needed because, on 32-bit platforms, size_t is only
+	 * 32-bits and this produces a warning because it's always false.
+	 * Casting to uint64_t inside the conditional is not sufficient to stop
+	 * the warning. */
+	if (in_len_64 >= (1ull << 32)*64-64)
+		{
+		EVPerr(EVP_F_AEAD_CHACHA20_POLY1305_OPEN, EVP_R_TOO_LARGE);
+		return -1;
+		}
+
+	if (nonce_len != CHACHA20_NONCE_LEN)
+		{
+		EVPerr(EVP_F_AEAD_CHACHA20_POLY1305_OPEN, EVP_R_IV_TOO_LARGE);
+		return -1;
+		}
+
+	out_len = in_len - c20_ctx->tag_len;
+
+	if (max_out_len < out_len)
+		{
+		EVPerr(EVP_F_AEAD_CHACHA20_POLY1305_OPEN, EVP_R_BUFFER_TOO_SMALL);
+		return -1;
+		}
+
+	memset(poly1305_key, 0, sizeof(poly1305_key));
+	CRYPTO_chacha_20(poly1305_key, poly1305_key, sizeof(poly1305_key), c20_ctx->key, nonce, 0);
+
+	CRYPTO_poly1305_init(&poly1305, poly1305_key);
+	poly1305_update_with_length(&poly1305, ad, ad_len);
+	poly1305_update_with_length(&poly1305, in, out_len);
+	CRYPTO_poly1305_finish(&poly1305, mac);
+
+	if (CRYPTO_memcmp(mac, in + out_len, c20_ctx->tag_len) != 0)
+		{
+		EVPerr(EVP_F_AEAD_CHACHA20_POLY1305_OPEN, EVP_R_BAD_DECRYPT);
+		return -1;
+		}
+
+	CRYPTO_chacha_20(out, in, out_len, c20_ctx->key, nonce, 1);
+	return out_len;
+	}
+
+static const EVP_AEAD aead_chacha20_poly1305 =
+	{
+	32,  /* key len */
+	CHACHA20_NONCE_LEN,   /* nonce len */
+	POLY1305_TAG_LEN,  /* overhead */
+	POLY1305_TAG_LEN,  /* max tag length */
+
+	aead_chacha20_poly1305_init,
+	aead_chacha20_poly1305_cleanup,
+	aead_chacha20_poly1305_seal,
+	aead_chacha20_poly1305_open,
+	};
+
+const EVP_AEAD *EVP_aead_chacha20_poly1305()
+	{
+	return &aead_chacha20_poly1305;
+	}
+
+#endif  /* !OPENSSL_NO_CHACHA && !OPENSSL_NO_POLY1305 */
diff --git a/lib/libcrypto/evp/evp.h b/lib/libcrypto/evp/evp.h
index f8395fbe7bd..437e36194ff 100644
--- a/lib/libcrypto/evp/evp.h
+++ b/lib/libcrypto/evp/evp.h
@@ -1222,6 +1222,11 @@ const EVP_AEAD *EVP_aead_aes_128_gcm(void);
 const EVP_AEAD *EVP_aead_aes_256_gcm(void);
 #endif
 
+#if !defined(OPENSSL_NO_CHACHA) && !defined(OPENSSL_NO_POLY1305)
+/* EVP_aead_chacha20_poly1305 is ChaCha20 with a Poly1305 authenticator. */
+const EVP_AEAD *EVP_aead_chacha20_poly1305(void);
+#endif
+
 /* EVP_AEAD_key_length returns the length of the keys used. */
 size_t EVP_AEAD_key_length(const EVP_AEAD *aead);
 
@@ -1323,6 +1328,9 @@ void ERR_load_EVP_strings(void);
 #define EVP_F_AEAD_AES_GCM_INIT				 187
 #define EVP_F_AEAD_AES_GCM_OPEN				 188
 #define EVP_F_AEAD_AES_GCM_SEAL				 189
+#define EVP_F_AEAD_CHACHA20_POLY1305_INIT		 192
+#define EVP_F_AEAD_CHACHA20_POLY1305_OPEN		 193
+#define EVP_F_AEAD_CHACHA20_POLY1305_SEAL		 194
 #define EVP_F_AEAD_CTX_OPEN				 185
 #define EVP_F_AEAD_CTX_SEAL				 186
 #define EVP_F_AESNI_INIT_KEY				 165
diff --git a/lib/libcrypto/evp/evp_err.c b/lib/libcrypto/evp/evp_err.c
index 9391036d0fc..e2aeb1db6b3 100644
--- a/lib/libcrypto/evp/evp_err.c
+++ b/lib/libcrypto/evp/evp_err.c
@@ -72,6 +72,9 @@ static ERR_STRING_DATA EVP_str_functs[] = {
 	{ERR_FUNC(EVP_F_AEAD_AES_GCM_INIT),	"AEAD_AES_GCM_INIT"},
 	{ERR_FUNC(EVP_F_AEAD_AES_GCM_OPEN),	"AEAD_AES_GCM_OPEN"},
 	{ERR_FUNC(EVP_F_AEAD_AES_GCM_SEAL),	"AEAD_AES_GCM_SEAL"},
+	{ERR_FUNC(EVP_F_AEAD_CHACHA20_POLY1305_INIT),	"AEAD_CHACHA20_POLY1305_INIT"},
+	{ERR_FUNC(EVP_F_AEAD_CHACHA20_POLY1305_OPEN),	"AEAD_CHACHA20_POLY1305_OPEN"},
+	{ERR_FUNC(EVP_F_AEAD_CHACHA20_POLY1305_SEAL),	"AEAD_CHACHA20_POLY1305_SEAL"},
 	{ERR_FUNC(EVP_F_AESNI_INIT_KEY),	"AESNI_INIT_KEY"},
 	{ERR_FUNC(EVP_F_AESNI_XTS_CIPHER),	"AESNI_XTS_CIPHER"},
 	{ERR_FUNC(EVP_F_AES_INIT_KEY),	"AES_INIT_KEY"},