third_party/openssl: add ChaCha20+Poly1305 support.

openssl/crypto/evp/e_chacha20poly1305.c

+/* ====================================================================
+ * 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_SEAL, 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 */