--- /dev/null
+/*
+ * Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the OpenSSL license (the "License"). You may not use
+ * this file except in compliance with the License. You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <stdio.h>
+#include "internal/cryptlib.h"
+
+#ifndef OPENSSL_NO_CHACHA
+
+# include <openssl/evp.h>
+# include <openssl/objects.h>
+# include "evp_locl.h"
+# include "internal/evp_int.h"
+# include "internal/chacha.h"
+
+typedef struct {
+ union {
+ double align; /* this ensures even sizeof(EVP_CHACHA_KEY)%8==0 */
+ unsigned int d[CHACHA_KEY_SIZE / 4];
+ } key;
+ unsigned int counter[CHACHA_CTR_SIZE / 4];
+ unsigned char buf[CHACHA_BLK_SIZE];
+ unsigned int partial_len;
+} EVP_CHACHA_KEY;
+
+#define data(ctx) ((EVP_CHACHA_KEY *)(ctx)->cipher_data)
+
+static int chacha_init_key(EVP_CIPHER_CTX *ctx,
+ const unsigned char user_key[CHACHA_KEY_SIZE],
+ const unsigned char iv[CHACHA_CTR_SIZE], int enc)
+{
+ EVP_CHACHA_KEY *key = data(ctx);
+ unsigned int i;
+
+ if (user_key)
+ for (i = 0; i < CHACHA_KEY_SIZE; i+=4) {
+ key->key.d[i/4] = CHACHA_U8TOU32(user_key+i);
+ }
+
+ if (iv)
+ for (i = 0; i < CHACHA_CTR_SIZE; i+=4) {
+ key->counter[i/4] = CHACHA_U8TOU32(iv+i);
+ }
+
+ key->partial_len = 0;
+
+ return 1;
+}
+
+static int chacha_cipher(EVP_CIPHER_CTX * ctx, unsigned char *out,
+ const unsigned char *inp, size_t len)
+{
+ EVP_CHACHA_KEY *key = data(ctx);
+ unsigned int n, rem, ctr32;
+
+ if ((n = key->partial_len)) {
+ while (len && n < CHACHA_BLK_SIZE) {
+ *out++ = *inp++ ^ key->buf[n++];
+ len--;
+ }
+ key->partial_len = n;
+
+ if (len == 0)
+ return 1;
+
+ if (n == CHACHA_BLK_SIZE) {
+ key->partial_len = 0;
+ key->counter[0]++;
+ if (key->counter[0] == 0)
+ key->counter[1]++;
+ }
+ }
+
+ rem = (unsigned int)(len % CHACHA_BLK_SIZE);
+ len -= rem;
+ ctr32 = key->counter[0];
+ while (len >= CHACHA_BLK_SIZE) {
+ size_t blocks = len / CHACHA_BLK_SIZE;
+ /*
+ * 1<<28 is just a not-so-small yet not-so-large number...
+ * Below condition is practically never met, but it has to
+ * be checked for code correctness.
+ */
+ if (sizeof(size_t)>sizeof(unsigned int) && blocks>(1U<<28))
+ blocks = (1U<<28);
+
+ /*
+ * As ChaCha20_ctr32 operates on 32-bit counter, caller
+ * has to handle overflow. 'if' below detects the
+ * overflow, which is then handled by limiting the
+ * amount of blocks to the exact overflow point...
+ */
+ ctr32 += (unsigned int)blocks;
+ if (ctr32 < blocks) {
+ blocks -= ctr32;
+ ctr32 = 0;
+ }
+ blocks *= CHACHA_BLK_SIZE;
+ ChaCha20_ctr32(out, inp, blocks, key->key.d, key->counter);
+ len -= blocks;
+ inp += blocks;
+ out += blocks;
+
+ key->counter[0] = ctr32;
+ if (ctr32 == 0) key->counter[1]++;
+ }
+
+ if (rem) {
+ memset(key->buf, 0, sizeof(key->buf));
+ ChaCha20_ctr32(key->buf, key->buf, CHACHA_BLK_SIZE,
+ key->key.d, key->counter);
+ for (n = 0; n < rem; n++)
+ out[n] = inp[n] ^ key->buf[n];
+ key->partial_len = rem;
+ }
+
+ return 1;
+}
+
+static const EVP_CIPHER chacha20 = {
+ NID_chacha20,
+ 1, /* block_size */
+ CHACHA_KEY_SIZE, /* key_len */
+ CHACHA_CTR_SIZE, /* iv_len, 128-bit counter in the context */
+ 0, /* flags */
+ chacha_init_key,
+ chacha_cipher,
+ NULL,
+ sizeof(EVP_CHACHA_KEY),
+ NULL,
+ NULL,
+ NULL,
+ NULL
+};
+
+const EVP_CIPHER *EVP_chacha20(void)
+{
+ return (&chacha20);
+}
+
+# ifndef OPENSSL_NO_POLY1305
+# include "internal/poly1305.h"
+
+typedef struct {
+ EVP_CHACHA_KEY key;
+ unsigned int nonce[12/4];
+ unsigned char tag[POLY1305_BLOCK_SIZE];
+ struct { uint64_t aad, text; } len;
+ int aad, mac_inited, tag_len, nonce_len;
+ size_t tls_payload_length;
+} EVP_CHACHA_AEAD_CTX;
+
+# define NO_TLS_PAYLOAD_LENGTH ((size_t)-1)
+# define aead_data(ctx) ((EVP_CHACHA_AEAD_CTX *)(ctx)->cipher_data)
+# define POLY1305_ctx(actx) ((POLY1305 *)(actx + 1))
+
+static int chacha20_poly1305_init_key(EVP_CIPHER_CTX *ctx,
+ const unsigned char *inkey,
+ const unsigned char *iv, int enc)
+{
+ EVP_CHACHA_AEAD_CTX *actx = aead_data(ctx);
+
+ if (!inkey && !iv)
+ return 1;
+
+ actx->len.aad = 0;
+ actx->len.text = 0;
+ actx->aad = 0;
+ actx->mac_inited = 0;
+ actx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH;
+
+ if (iv != NULL) {
+ unsigned char temp[CHACHA_CTR_SIZE] = { 0 };
+
+ /* pad on the left */
+ if (actx->nonce_len <= CHACHA_CTR_SIZE)
+ memcpy(temp + CHACHA_CTR_SIZE - actx->nonce_len, iv, actx->nonce_len);
+
+ chacha_init_key(ctx, inkey, temp, enc);
+
+ actx->nonce[0] = actx->key.counter[1];
+ actx->nonce[1] = actx->key.counter[2];
+ actx->nonce[2] = actx->key.counter[3];
+ } else {
+ chacha_init_key(ctx, inkey, NULL, enc);
+ }
+
+ return 1;
+}
+
+static int chacha20_poly1305_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
+ const unsigned char *in, size_t len)
+{
+ EVP_CHACHA_AEAD_CTX *actx = aead_data(ctx);
+ size_t rem, plen = actx->tls_payload_length;
+ static const unsigned char zero[POLY1305_BLOCK_SIZE] = { 0 };
+
+ if (!actx->mac_inited) {
+ actx->key.counter[0] = 0;
+ memset(actx->key.buf, 0, sizeof(actx->key.buf));
+ ChaCha20_ctr32(actx->key.buf, actx->key.buf, CHACHA_BLK_SIZE,
+ actx->key.key.d, actx->key.counter);
+ Poly1305_Init(POLY1305_ctx(actx), actx->key.buf);
+ actx->key.counter[0] = 1;
+ actx->key.partial_len = 0;
+ actx->len.aad = actx->len.text = 0;
+ actx->mac_inited = 1;
+ }
+
+ if (in) { /* aad or text */
+ if (out == NULL) { /* aad */
+ Poly1305_Update(POLY1305_ctx(actx), in, len);
+ actx->len.aad += len;
+ actx->aad = 1;
+ return len;
+ } else { /* plain- or ciphertext */
+ if (actx->aad) { /* wrap up aad */
+ if ((rem = (size_t)actx->len.aad % POLY1305_BLOCK_SIZE))
+ Poly1305_Update(POLY1305_ctx(actx), zero,
+ POLY1305_BLOCK_SIZE - rem);
+ actx->aad = 0;
+ }
+
+ actx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH;
+ if (plen == NO_TLS_PAYLOAD_LENGTH)
+ plen = len;
+ else if (len != plen + POLY1305_BLOCK_SIZE)
+ return -1;
+
+ if (ctx->encrypt) { /* plaintext */
+ chacha_cipher(ctx, out, in, plen);
+ Poly1305_Update(POLY1305_ctx(actx), out, plen);
+ in += plen;
+ out += plen;
+ actx->len.text += plen;
+ } else { /* ciphertext */
+ Poly1305_Update(POLY1305_ctx(actx), in, plen);
+ chacha_cipher(ctx, out, in, plen);
+ in += plen;
+ out += plen;
+ actx->len.text += plen;
+ }
+ }
+ }
+ if (in == NULL /* explicit final */
+ || plen != len) { /* or tls mode */
+ const union {
+ long one;
+ char little;
+ } is_endian = { 1 };
+ unsigned char temp[POLY1305_BLOCK_SIZE];
+
+ if (actx->aad) { /* wrap up aad */
+ if ((rem = (size_t)actx->len.aad % POLY1305_BLOCK_SIZE))
+ Poly1305_Update(POLY1305_ctx(actx), zero,
+ POLY1305_BLOCK_SIZE - rem);
+ actx->aad = 0;
+ }
+
+ if ((rem = (size_t)actx->len.text % POLY1305_BLOCK_SIZE))
+ Poly1305_Update(POLY1305_ctx(actx), zero,
+ POLY1305_BLOCK_SIZE - rem);
+
+ if (is_endian.little) {
+ Poly1305_Update(POLY1305_ctx(actx),
+ (unsigned char *)&actx->len, POLY1305_BLOCK_SIZE);
+ } else {
+ temp[0] = (unsigned char)(actx->len.aad);
+ temp[1] = (unsigned char)(actx->len.aad>>8);
+ temp[2] = (unsigned char)(actx->len.aad>>16);
+ temp[3] = (unsigned char)(actx->len.aad>>24);
+ temp[4] = (unsigned char)(actx->len.aad>>32);
+ temp[5] = (unsigned char)(actx->len.aad>>40);
+ temp[6] = (unsigned char)(actx->len.aad>>48);
+ temp[7] = (unsigned char)(actx->len.aad>>56);
+
+ temp[8] = (unsigned char)(actx->len.text);
+ temp[9] = (unsigned char)(actx->len.text>>8);
+ temp[10] = (unsigned char)(actx->len.text>>16);
+ temp[11] = (unsigned char)(actx->len.text>>24);
+ temp[12] = (unsigned char)(actx->len.text>>32);
+ temp[13] = (unsigned char)(actx->len.text>>40);
+ temp[14] = (unsigned char)(actx->len.text>>48);
+ temp[15] = (unsigned char)(actx->len.text>>56);
+
+ Poly1305_Update(POLY1305_ctx(actx), temp, POLY1305_BLOCK_SIZE);
+ }
+ Poly1305_Final(POLY1305_ctx(actx), ctx->encrypt ? actx->tag
+ : temp);
+ actx->mac_inited = 0;
+
+ if (in != NULL && len != plen) { /* tls mode */
+ if (ctx->encrypt) {
+ memcpy(out, actx->tag, POLY1305_BLOCK_SIZE);
+ } else {
+ if (CRYPTO_memcmp(temp, in, POLY1305_BLOCK_SIZE)) {
+ memset(out - plen, 0, plen);
+ return -1;
+ }
+ }
+ }
+ else if (!ctx->encrypt) {
+ if (CRYPTO_memcmp(temp, actx->tag, actx->tag_len))
+ return -1;
+ }
+ }
+ return len;
+}
+
+static int chacha20_poly1305_cleanup(EVP_CIPHER_CTX *ctx)
+{
+ EVP_CHACHA_AEAD_CTX *actx = aead_data(ctx);
+ if (actx)
+ OPENSSL_cleanse(ctx->cipher_data, sizeof(*ctx) + Poly1305_ctx_size());
+ return 1;
+}
+
+static int chacha20_poly1305_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg,
+ void *ptr)
+{
+ EVP_CHACHA_AEAD_CTX *actx = aead_data(ctx);
+
+ switch(type) {
+ case EVP_CTRL_INIT:
+ if (actx == NULL)
+ actx = ctx->cipher_data
+ = OPENSSL_zalloc(sizeof(*actx) + Poly1305_ctx_size());
+ if (actx == NULL) {
+ EVPerr(EVP_F_CHACHA20_POLY1305_CTRL, EVP_R_INITIALIZATION_ERROR);
+ return 0;
+ }
+ actx->len.aad = 0;
+ actx->len.text = 0;
+ actx->aad = 0;
+ actx->mac_inited = 0;
+ actx->tag_len = 0;
+ actx->nonce_len = 12;
+ actx->tls_payload_length = NO_TLS_PAYLOAD_LENGTH;
+ return 1;
+
+ case EVP_CTRL_COPY:
+ if (actx) {
+ EVP_CIPHER_CTX *dst = (EVP_CIPHER_CTX *)ptr;
+
+ dst->cipher_data =
+ OPENSSL_memdup(actx, sizeof(*actx) + Poly1305_ctx_size());
+ if (dst->cipher_data == NULL) {
+ EVPerr(EVP_F_CHACHA20_POLY1305_CTRL, EVP_R_COPY_ERROR);
+ return 0;
+ }
+ }
+ return 1;
+
+ case EVP_CTRL_AEAD_SET_IVLEN:
+ if (arg <= 0 || arg > CHACHA_CTR_SIZE)
+ return 0;
+ actx->nonce_len = arg;
+ return 1;
+
+ case EVP_CTRL_AEAD_SET_IV_FIXED:
+ if (arg != 12)
+ return 0;
+ actx->nonce[0] = actx->key.counter[1]
+ = CHACHA_U8TOU32((unsigned char *)ptr);
+ actx->nonce[1] = actx->key.counter[2]
+ = CHACHA_U8TOU32((unsigned char *)ptr+4);
+ actx->nonce[2] = actx->key.counter[3]
+ = CHACHA_U8TOU32((unsigned char *)ptr+8);
+ return 1;
+
+ case EVP_CTRL_AEAD_SET_TAG:
+ if (arg <= 0 || arg > POLY1305_BLOCK_SIZE)
+ return 0;
+ if (ptr != NULL) {
+ memcpy(actx->tag, ptr, arg);
+ actx->tag_len = arg;
+ }
+ return 1;
+
+ case EVP_CTRL_AEAD_GET_TAG:
+ if (arg <= 0 || arg > POLY1305_BLOCK_SIZE || !ctx->encrypt)
+ return 0;
+ memcpy(ptr, actx->tag, arg);
+ return 1;
+
+ case EVP_CTRL_AEAD_TLS1_AAD:
+ if (arg != EVP_AEAD_TLS1_AAD_LEN)
+ return 0;
+ {
+ unsigned int len;
+ unsigned char *aad = ptr, temp[POLY1305_BLOCK_SIZE];
+
+ len = aad[EVP_AEAD_TLS1_AAD_LEN - 2] << 8 |
+ aad[EVP_AEAD_TLS1_AAD_LEN - 1];
+ if (!ctx->encrypt) {
+ len -= POLY1305_BLOCK_SIZE; /* discount attached tag */
+ memcpy(temp, aad, EVP_AEAD_TLS1_AAD_LEN - 2);
+ aad = temp;
+ temp[EVP_AEAD_TLS1_AAD_LEN - 2] = (unsigned char)(len >> 8);
+ temp[EVP_AEAD_TLS1_AAD_LEN - 1] = (unsigned char)len;
+ }
+ actx->tls_payload_length = len;
+
+ /*
+ * merge record sequence number as per
+ * draft-ietf-tls-chacha20-poly1305-03
+ */
+ actx->key.counter[1] = actx->nonce[0];
+ actx->key.counter[2] = actx->nonce[1] ^ CHACHA_U8TOU32(aad);
+ actx->key.counter[3] = actx->nonce[2] ^ CHACHA_U8TOU32(aad+4);
+ actx->mac_inited = 0;
+ chacha20_poly1305_cipher(ctx, NULL, aad, EVP_AEAD_TLS1_AAD_LEN);
+ return POLY1305_BLOCK_SIZE; /* tag length */
+ }
+
+ case EVP_CTRL_AEAD_SET_MAC_KEY:
+ /* no-op */
+ return 1;
+
+ default:
+ return -1;
+ }
+}
+
+static EVP_CIPHER chacha20_poly1305 = {
+ NID_chacha20_poly1305,
+ 1, /* block_size */
+ CHACHA_KEY_SIZE, /* key_len */
+ 12, /* iv_len, 96-bit nonce in the context */
+ EVP_CIPH_FLAG_AEAD_CIPHER | EVP_CIPH_CUSTOM_IV |
+ EVP_CIPH_ALWAYS_CALL_INIT | EVP_CIPH_CTRL_INIT |
+ EVP_CIPH_CUSTOM_COPY | EVP_CIPH_FLAG_CUSTOM_CIPHER,
+ chacha20_poly1305_init_key,
+ chacha20_poly1305_cipher,
+ chacha20_poly1305_cleanup,
+ 0, /* 0 moves context-specific structure allocation to ctrl */
+ NULL, /* set_asn1_parameters */
+ NULL, /* get_asn1_parameters */
+ chacha20_poly1305_ctrl,
+ NULL /* app_data */
+};
+
+const EVP_CIPHER *EVP_chacha20_poly1305(void)
+{
+ return(&chacha20_poly1305);
+}
+# endif
+#endif
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