--- /dev/null
+/* Copyright (c) 2014, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#include <openssl/aead.h>
+
+#include <string.h>
+
+#include <openssl/chacha.h>
+#include <openssl/cipher.h>
+#include <openssl/cpu.h>
+#include <openssl/err.h>
+#include <openssl/mem.h>
+#include <openssl/poly1305.h>
+#include <openssl/type_check.h>
+
+#include "../fipsmodule/cipher/internal.h"
+#include "../internal.h"
+
+
+#define POLY1305_TAG_LEN 16
+
+struct aead_chacha20_poly1305_ctx {
+ uint8_t key[32];
+};
+
+// For convenience (the x86_64 calling convention allows only six parameters in
+// registers), the final parameter for the assembly functions is both an input
+// and output parameter.
+union open_data {
+ struct {
+ alignas(16) uint8_t key[32];
+ uint32_t counter;
+ uint8_t nonce[12];
+ } in;
+ struct {
+ uint8_t tag[POLY1305_TAG_LEN];
+ } out;
+};
+
+union seal_data {
+ struct {
+ alignas(16) uint8_t key[32];
+ uint32_t counter;
+ uint8_t nonce[12];
+ const uint8_t *extra_ciphertext;
+ size_t extra_ciphertext_len;
+ } in;
+ struct {
+ uint8_t tag[POLY1305_TAG_LEN];
+ } out;
+};
+
+#if defined(OPENSSL_X86_64) && !defined(OPENSSL_NO_ASM) && \
+ !defined(OPENSSL_WINDOWS)
+static int asm_capable(void) {
+ const int sse41_capable = (OPENSSL_ia32cap_P[1] & (1 << 19)) != 0;
+ return sse41_capable;
+}
+
+OPENSSL_COMPILE_ASSERT(sizeof(union open_data) == 48, wrong_open_data_size);
+OPENSSL_COMPILE_ASSERT(sizeof(union seal_data) == 48 + 8 + 8,
+ wrong_seal_data_size);
+
+// chacha20_poly1305_open is defined in chacha20_poly1305_x86_64.pl. It decrypts
+// |plaintext_len| bytes from |ciphertext| and writes them to |out_plaintext|.
+// Additional input parameters are passed in |aead_data->in|. On exit, it will
+// write calculated tag value to |aead_data->out.tag|, which the caller must
+// check.
+extern void chacha20_poly1305_open(uint8_t *out_plaintext,
+ const uint8_t *ciphertext,
+ size_t plaintext_len, const uint8_t *ad,
+ size_t ad_len, union open_data *aead_data);
+
+// chacha20_poly1305_open is defined in chacha20_poly1305_x86_64.pl. It encrypts
+// |plaintext_len| bytes from |plaintext| and writes them to |out_ciphertext|.
+// Additional input parameters are passed in |aead_data->in|. The calculated tag
+// value is over the computed ciphertext concatenated with |extra_ciphertext|
+// and written to |aead_data->out.tag|.
+extern void chacha20_poly1305_seal(uint8_t *out_ciphertext,
+ const uint8_t *plaintext,
+ size_t plaintext_len, const uint8_t *ad,
+ size_t ad_len, union seal_data *aead_data);
+#else
+static int asm_capable(void) { return 0; }
+
+
+static void chacha20_poly1305_open(uint8_t *out_plaintext,
+ const uint8_t *ciphertext,
+ size_t plaintext_len, const uint8_t *ad,
+ size_t ad_len, union open_data *aead_data) {}
+
+static void chacha20_poly1305_seal(uint8_t *out_ciphertext,
+ const uint8_t *plaintext,
+ size_t plaintext_len, const uint8_t *ad,
+ size_t ad_len, union seal_data *aead_data) {}
+#endif
+
+static int aead_chacha20_poly1305_init(EVP_AEAD_CTX *ctx, const uint8_t *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) {
+ OPENSSL_PUT_ERROR(CIPHER, CIPHER_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;
+ }
+
+ OPENSSL_memcpy(c20_ctx->key, key, key_len);
+ ctx->aead_state = c20_ctx;
+ ctx->tag_len = tag_len;
+
+ return 1;
+}
+
+static void aead_chacha20_poly1305_cleanup(EVP_AEAD_CTX *ctx) {
+ OPENSSL_free(ctx->aead_state);
+}
+
+static void poly1305_update_length(poly1305_state *poly1305, size_t data_len) {
+ uint8_t length_bytes[8];
+
+ for (unsigned i = 0; i < sizeof(length_bytes); i++) {
+ length_bytes[i] = data_len;
+ data_len >>= 8;
+ }
+
+ CRYPTO_poly1305_update(poly1305, length_bytes, sizeof(length_bytes));
+}
+
+// calc_tag fills |tag| with the authentication tag for the given inputs.
+static void calc_tag(uint8_t tag[POLY1305_TAG_LEN],
+ const struct aead_chacha20_poly1305_ctx *c20_ctx,
+ const uint8_t nonce[12], const uint8_t *ad, size_t ad_len,
+ const uint8_t *ciphertext, size_t ciphertext_len,
+ const uint8_t *ciphertext_extra,
+ size_t ciphertext_extra_len) {
+ alignas(16) uint8_t poly1305_key[32];
+ OPENSSL_memset(poly1305_key, 0, sizeof(poly1305_key));
+ CRYPTO_chacha_20(poly1305_key, poly1305_key, sizeof(poly1305_key),
+ c20_ctx->key, nonce, 0);
+
+ static const uint8_t padding[16] = { 0 }; // Padding is all zeros.
+ poly1305_state ctx;
+ CRYPTO_poly1305_init(&ctx, poly1305_key);
+ CRYPTO_poly1305_update(&ctx, ad, ad_len);
+ if (ad_len % 16 != 0) {
+ CRYPTO_poly1305_update(&ctx, padding, sizeof(padding) - (ad_len % 16));
+ }
+ CRYPTO_poly1305_update(&ctx, ciphertext, ciphertext_len);
+ CRYPTO_poly1305_update(&ctx, ciphertext_extra, ciphertext_extra_len);
+ const size_t ciphertext_total = ciphertext_len + ciphertext_extra_len;
+ if (ciphertext_total % 16 != 0) {
+ CRYPTO_poly1305_update(&ctx, padding,
+ sizeof(padding) - (ciphertext_total % 16));
+ }
+ poly1305_update_length(&ctx, ad_len);
+ poly1305_update_length(&ctx, ciphertext_total);
+ CRYPTO_poly1305_finish(&ctx, tag);
+}
+
+static int aead_chacha20_poly1305_seal_scatter(
+ const EVP_AEAD_CTX *ctx, uint8_t *out, uint8_t *out_tag,
+ size_t *out_tag_len, size_t max_out_tag_len, const uint8_t *nonce,
+ size_t nonce_len, const uint8_t *in, size_t in_len, const uint8_t *extra_in,
+ size_t extra_in_len, const uint8_t *ad, size_t ad_len) {
+ const struct aead_chacha20_poly1305_ctx *c20_ctx = ctx->aead_state;
+
+ if (extra_in_len + ctx->tag_len < ctx->tag_len) {
+ OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE);
+ return 0;
+ }
+ if (max_out_tag_len < ctx->tag_len + extra_in_len) {
+ OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BUFFER_TOO_SMALL);
+ return 0;
+ }
+ if (nonce_len != 12) {
+ OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_UNSUPPORTED_NONCE_SIZE);
+ return 0;
+ }
+
+ // |CRYPTO_chacha_20| uses a 32-bit block counter. Therefore we disallow
+ // individual operations that work on more than 256GB 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.
+ const uint64_t in_len_64 = in_len;
+ if (in_len_64 >= (UINT64_C(1) << 32) * 64 - 64) {
+ OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE);
+ return 0;
+ }
+
+ if (max_out_tag_len < ctx->tag_len) {
+ OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BUFFER_TOO_SMALL);
+ return 0;
+ }
+
+ // The the extra input is given, it is expected to be very short and so is
+ // encrypted byte-by-byte first.
+ if (extra_in_len) {
+ static const size_t kChaChaBlockSize = 64;
+ uint32_t block_counter = 1 + (in_len / kChaChaBlockSize);
+ size_t offset = in_len % kChaChaBlockSize;
+ uint8_t block[64 /* kChaChaBlockSize */];
+
+ for (size_t done = 0; done < extra_in_len; block_counter++) {
+ memset(block, 0, sizeof(block));
+ CRYPTO_chacha_20(block, block, sizeof(block), c20_ctx->key, nonce,
+ block_counter);
+ for (size_t i = offset; i < sizeof(block) && done < extra_in_len;
+ i++, done++) {
+ out_tag[done] = extra_in[done] ^ block[i];
+ }
+ offset = 0;
+ }
+ }
+
+ union seal_data data;
+ if (asm_capable()) {
+ OPENSSL_memcpy(data.in.key, c20_ctx->key, 32);
+ data.in.counter = 0;
+ OPENSSL_memcpy(data.in.nonce, nonce, 12);
+ data.in.extra_ciphertext = out_tag;
+ data.in.extra_ciphertext_len = extra_in_len;
+ chacha20_poly1305_seal(out, in, in_len, ad, ad_len, &data);
+ } else {
+ CRYPTO_chacha_20(out, in, in_len, c20_ctx->key, nonce, 1);
+ calc_tag(data.out.tag, c20_ctx, nonce, ad, ad_len, out, in_len, out_tag,
+ extra_in_len);
+ }
+
+ OPENSSL_memcpy(out_tag + extra_in_len, data.out.tag, ctx->tag_len);
+ *out_tag_len = extra_in_len + ctx->tag_len;
+ return 1;
+}
+
+static int aead_chacha20_poly1305_open_gather(
+ const EVP_AEAD_CTX *ctx, uint8_t *out, const uint8_t *nonce,
+ size_t nonce_len, const uint8_t *in, size_t in_len, const uint8_t *in_tag,
+ size_t in_tag_len, const uint8_t *ad, size_t ad_len) {
+ const struct aead_chacha20_poly1305_ctx *c20_ctx = ctx->aead_state;
+
+ if (nonce_len != 12) {
+ OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_UNSUPPORTED_NONCE_SIZE);
+ return 0;
+ }
+
+ if (in_tag_len != ctx->tag_len) {
+ OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT);
+ return 0;
+ }
+
+ // |CRYPTO_chacha_20| uses a 32-bit block counter. Therefore we disallow
+ // individual operations that work on more than 256GB 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.
+ const uint64_t in_len_64 = in_len;
+ if (in_len_64 >= (UINT64_C(1) << 32) * 64 - 64) {
+ OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE);
+ return 0;
+ }
+
+ union open_data data;
+ if (asm_capable()) {
+ OPENSSL_memcpy(data.in.key, c20_ctx->key, 32);
+ data.in.counter = 0;
+ OPENSSL_memcpy(data.in.nonce, nonce, 12);
+ chacha20_poly1305_open(out, in, in_len, ad, ad_len, &data);
+ } else {
+ calc_tag(data.out.tag, c20_ctx, nonce, ad, ad_len, in, in_len, NULL, 0);
+ CRYPTO_chacha_20(out, in, in_len, c20_ctx->key, nonce, 1);
+ }
+
+ if (CRYPTO_memcmp(data.out.tag, in_tag, ctx->tag_len) != 0) {
+ OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT);
+ return 0;
+ }
+
+ return 1;
+}
+
+static const EVP_AEAD aead_chacha20_poly1305 = {
+ 32, // key len
+ 12, // nonce len
+ POLY1305_TAG_LEN, // overhead
+ POLY1305_TAG_LEN, // max tag length
+ 1, // seal_scatter_supports_extra_in
+
+ aead_chacha20_poly1305_init,
+ NULL, // init_with_direction
+ aead_chacha20_poly1305_cleanup,
+ NULL /* open */,
+ aead_chacha20_poly1305_seal_scatter,
+ aead_chacha20_poly1305_open_gather,
+ NULL, // get_iv
+ NULL, // tag_len
+};
+
+const EVP_AEAD *EVP_aead_chacha20_poly1305(void) {
+ return &aead_chacha20_poly1305;
+}
git://repos.xcallymotion.com / motion2.git / blobdiff