diff options
Diffstat (limited to 'src/crypto/cipher/e_chacha20poly1305.c')
-rw-r--r-- | src/crypto/cipher/e_chacha20poly1305.c | 207 |
1 files changed, 147 insertions, 60 deletions
diff --git a/src/crypto/cipher/e_chacha20poly1305.c b/src/crypto/cipher/e_chacha20poly1305.c index 9dda1b0..3bf7834 100644 --- a/src/crypto/cipher/e_chacha20poly1305.c +++ b/src/crypto/cipher/e_chacha20poly1305.c @@ -26,7 +26,6 @@ #define POLY1305_TAG_LEN 16 -#define CHACHA20_NONCE_LEN 8 struct aead_chacha20_poly1305_ctx { unsigned char key[32]; @@ -68,18 +67,15 @@ static void aead_chacha20_poly1305_cleanup(EVP_AEAD_CTX *ctx) { OPENSSL_free(c20_ctx); } -static void poly1305_update_with_length(poly1305_state *poly1305, - const uint8_t *data, size_t data_len) { - size_t j = data_len; +static void poly1305_update_length(poly1305_state *poly1305, size_t data_len) { uint8_t length_bytes[8]; unsigned i; for (i = 0; i < sizeof(length_bytes); i++) { - length_bytes[i] = j; - j >>= 8; + length_bytes[i] = data_len; + data_len >>= 8; } - CRYPTO_poly1305_update(poly1305, data, data_len); CRYPTO_poly1305_update(poly1305, length_bytes, sizeof(length_bytes)); } @@ -89,18 +85,37 @@ static void poly1305_update_with_length(poly1305_state *poly1305, #define ALIGNED #endif -static int aead_chacha20_poly1305_seal(const EVP_AEAD_CTX *ctx, uint8_t *out, - size_t *out_len, size_t max_out_len, - const uint8_t *nonce, size_t nonce_len, - const uint8_t *in, size_t in_len, - const uint8_t *ad, size_t ad_len) { - const struct aead_chacha20_poly1305_ctx *c20_ctx = ctx->aead_state; +typedef void (*aead_poly1305_update)(poly1305_state *ctx, const uint8_t *ad, + size_t ad_len, const uint8_t *ciphertext, + size_t ciphertext_len); + +/* aead_poly1305 fills |tag| with the authentication tag for the given + * inputs, using |update| to control the order and format that the inputs are + * signed/authenticated. */ +static void aead_poly1305(aead_poly1305_update update, + 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) { uint8_t poly1305_key[32] ALIGNED; - poly1305_state poly1305; + memset(poly1305_key, 0, sizeof(poly1305_key)); + CRYPTO_chacha_20(poly1305_key, poly1305_key, sizeof(poly1305_key), + c20_ctx->key, nonce, 0); + poly1305_state ctx; + CRYPTO_poly1305_init(&ctx, poly1305_key); + update(&ctx, ad, ad_len, ciphertext, ciphertext_len); + CRYPTO_poly1305_finish(&ctx, tag); +} + +static int seal(aead_poly1305_update poly1305_update, const EVP_AEAD_CTX *ctx, + uint8_t *out, size_t *out_len, size_t max_out_len, + const uint8_t nonce[12], const uint8_t *in, size_t in_len, + const uint8_t *ad, size_t ad_len) { + const struct aead_chacha20_poly1305_ctx *c20_ctx = ctx->aead_state; 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 + /* |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. @@ -121,37 +136,22 @@ static int aead_chacha20_poly1305_seal(const EVP_AEAD_CTX *ctx, uint8_t *out, return 0; } - if (nonce_len != CHACHA20_NONCE_LEN) { - OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_IV_TOO_LARGE); - return 0; - } - - 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); uint8_t tag[POLY1305_TAG_LEN] ALIGNED; - CRYPTO_poly1305_finish(&poly1305, tag); + aead_poly1305(poly1305_update, tag, c20_ctx, nonce, ad, ad_len, out, in_len); + memcpy(out + in_len, tag, c20_ctx->tag_len); *out_len = in_len + c20_ctx->tag_len; return 1; } -static int aead_chacha20_poly1305_open(const EVP_AEAD_CTX *ctx, uint8_t *out, - size_t *out_len, size_t max_out_len, - const uint8_t *nonce, size_t nonce_len, - const uint8_t *in, size_t in_len, - const uint8_t *ad, size_t ad_len) { +static int open(aead_poly1305_update poly1305_update, const EVP_AEAD_CTX *ctx, + uint8_t *out, size_t *out_len, size_t max_out_len, + const uint8_t nonce[12], const uint8_t *in, size_t in_len, + const uint8_t *ad, size_t ad_len) { const struct aead_chacha20_poly1305_ctx *c20_ctx = ctx->aead_state; - uint8_t mac[POLY1305_TAG_LEN]; - uint8_t poly1305_key[32] ALIGNED; size_t plaintext_len; - poly1305_state poly1305; const uint64_t in_len_64 = in_len; if (in_len < c20_ctx->tag_len) { @@ -159,8 +159,7 @@ static int aead_chacha20_poly1305_open(const EVP_AEAD_CTX *ctx, uint8_t *out, return 0; } - /* The underlying ChaCha implementation may not overflow the block - * counter into the second counter word. Therefore we disallow + /* |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. @@ -171,40 +170,68 @@ static int aead_chacha20_poly1305_open(const EVP_AEAD_CTX *ctx, uint8_t *out, return 0; } - if (nonce_len != CHACHA20_NONCE_LEN) { - OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_IV_TOO_LARGE); + plaintext_len = in_len - c20_ctx->tag_len; + uint8_t tag[POLY1305_TAG_LEN] ALIGNED; + aead_poly1305(poly1305_update, tag, c20_ctx, nonce, ad, ad_len, in, + plaintext_len); + if (CRYPTO_memcmp(tag, in + plaintext_len, c20_ctx->tag_len) != 0) { + OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT); return 0; } - plaintext_len = in_len - c20_ctx->tag_len; + CRYPTO_chacha_20(out, in, plaintext_len, c20_ctx->key, nonce, 1); + *out_len = plaintext_len; + return 1; +} - if (max_out_len < plaintext_len) { - OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BUFFER_TOO_SMALL); - return 0; - } +static void poly1305_update_padded_16(poly1305_state *poly1305, + const uint8_t *data, size_t data_len) { + static const uint8_t padding[16] = { 0 }; /* Padding is all zeros. */ - memset(poly1305_key, 0, sizeof(poly1305_key)); - CRYPTO_chacha_20(poly1305_key, poly1305_key, sizeof(poly1305_key), - c20_ctx->key, nonce, 0); + CRYPTO_poly1305_update(poly1305, data, data_len); + if (data_len % 16 != 0) { + CRYPTO_poly1305_update(poly1305, padding, sizeof(padding) - (data_len % 16)); + } +} - CRYPTO_poly1305_init(&poly1305, poly1305_key); - poly1305_update_with_length(&poly1305, ad, ad_len); - poly1305_update_with_length(&poly1305, in, plaintext_len); - CRYPTO_poly1305_finish(&poly1305, mac); +static void poly1305_update(poly1305_state *ctx, const uint8_t *ad, + size_t ad_len, const uint8_t *ciphertext, + size_t ciphertext_len) { + poly1305_update_padded_16(ctx, ad, ad_len); + poly1305_update_padded_16(ctx, ciphertext, ciphertext_len); + poly1305_update_length(ctx, ad_len); + poly1305_update_length(ctx, ciphertext_len); +} - if (CRYPTO_memcmp(mac, in + plaintext_len, c20_ctx->tag_len) != 0) { - OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT); +static int aead_chacha20_poly1305_seal(const EVP_AEAD_CTX *ctx, uint8_t *out, + size_t *out_len, size_t max_out_len, + const uint8_t *nonce, size_t nonce_len, + const uint8_t *in, size_t in_len, + const uint8_t *ad, size_t ad_len) { + if (nonce_len != 12) { + OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_UNSUPPORTED_NONCE_SIZE); return 0; } + return seal(poly1305_update, ctx, out, out_len, max_out_len, nonce, in, + in_len, ad, ad_len); +} - CRYPTO_chacha_20(out, in, plaintext_len, c20_ctx->key, nonce, 1); - *out_len = plaintext_len; - return 1; +static int aead_chacha20_poly1305_open(const EVP_AEAD_CTX *ctx, uint8_t *out, + size_t *out_len, size_t max_out_len, + const uint8_t *nonce, size_t nonce_len, + const uint8_t *in, size_t in_len, + const uint8_t *ad, size_t ad_len) { + if (nonce_len != 12) { + OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_UNSUPPORTED_NONCE_SIZE); + return 0; + } + return open(poly1305_update, ctx, out, out_len, max_out_len, nonce, in, + in_len, ad, ad_len); } static const EVP_AEAD aead_chacha20_poly1305 = { 32, /* key len */ - CHACHA20_NONCE_LEN, /* nonce len */ + 12, /* nonce len */ POLY1305_TAG_LEN, /* overhead */ POLY1305_TAG_LEN, /* max tag length */ aead_chacha20_poly1305_init, @@ -215,6 +242,66 @@ static const EVP_AEAD aead_chacha20_poly1305 = { NULL, /* get_rc4_state */ }; -const EVP_AEAD *EVP_aead_chacha20_poly1305(void) { +const EVP_AEAD *EVP_aead_chacha20_poly1305_rfc7539(void) { return &aead_chacha20_poly1305; } + +static void poly1305_update_old(poly1305_state *ctx, const uint8_t *ad, + size_t ad_len, const uint8_t *ciphertext, + size_t ciphertext_len) { + CRYPTO_poly1305_update(ctx, ad, ad_len); + poly1305_update_length(ctx, ad_len); + CRYPTO_poly1305_update(ctx, ciphertext, ciphertext_len); + poly1305_update_length(ctx, ciphertext_len); +} + +static int aead_chacha20_poly1305_old_seal( + const EVP_AEAD_CTX *ctx, uint8_t *out, size_t *out_len, size_t max_out_len, + const uint8_t *nonce, size_t nonce_len, const uint8_t *in, size_t in_len, + const uint8_t *ad, size_t ad_len) { + if (nonce_len != 8) { + OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_UNSUPPORTED_NONCE_SIZE); + return 0; + } + uint8_t nonce_96[12]; + memset(nonce_96, 0, 4); + memcpy(nonce_96 + 4, nonce, 8); + return seal(poly1305_update_old, ctx, out, out_len, max_out_len, nonce_96, in, + in_len, ad, ad_len); +} + +static int aead_chacha20_poly1305_old_open( + const EVP_AEAD_CTX *ctx, uint8_t *out, size_t *out_len, size_t max_out_len, + const uint8_t *nonce, size_t nonce_len, const uint8_t *in, size_t in_len, + const uint8_t *ad, size_t ad_len) { + if (nonce_len != 8) { + OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_UNSUPPORTED_NONCE_SIZE); + return 0; + } + uint8_t nonce_96[12]; + memset(nonce_96, 0, 4); + memcpy(nonce_96 + 4, nonce, 8); + return open(poly1305_update_old, ctx, out, out_len, max_out_len, nonce_96, in, + in_len, ad, ad_len); +} + +static const EVP_AEAD aead_chacha20_poly1305_old = { + 32, /* key len */ + 8, /* nonce len */ + POLY1305_TAG_LEN, /* overhead */ + POLY1305_TAG_LEN, /* max tag length */ + aead_chacha20_poly1305_init, + NULL, /* init_with_direction */ + aead_chacha20_poly1305_cleanup, + aead_chacha20_poly1305_old_seal, + aead_chacha20_poly1305_old_open, + NULL, /* get_rc4_state */ +}; + +const EVP_AEAD *EVP_aead_chacha20_poly1305_old(void) { + return &aead_chacha20_poly1305_old; +} + +const EVP_AEAD *EVP_aead_chacha20_poly1305(void) { + return &aead_chacha20_poly1305_old; +} |