| From 98f0c6e114f55b4451bea824b05ab29db3351f12 Mon Sep 17 00:00:00 2001 |
| From: Adam Langley <agl@chromium.org> |
| Date: Thu, 25 Jul 2013 16:52:35 -0400 |
| Subject: [PATCH 40/50] aead_support |
| |
| This change adds an AEAD interface to EVP and an AES-GCM implementation |
| suitable for use in TLS. |
| --- |
| crypto/evp/Makefile | 4 +- |
| crypto/evp/e_aes.c | 214 +++++++++++++++++++++++++++++++++++---- |
| crypto/evp/evp.h | 111 ++++++++++++++++++++ |
| crypto/evp/evp_aead.c | 192 +++++++++++++++++++++++++++++++++++ |
| crypto/evp/evp_err.c | 8 ++ |
| crypto/evp/evp_locl.h | 24 +++++ |
| doc/crypto/EVP_AEAD_CTX_init.pod | 96 ++++++++++++++++++ |
| 7 files changed, 626 insertions(+), 23 deletions(-) |
| create mode 100644 crypto/evp/evp_aead.c |
| create mode 100644 doc/crypto/EVP_AEAD_CTX_init.pod |
| |
| diff --git a/crypto/evp/Makefile b/crypto/evp/Makefile |
| index 1e46ceb..b73038d 100644 |
| --- a/crypto/evp/Makefile |
| +++ b/crypto/evp/Makefile |
| @@ -29,7 +29,7 @@ LIBSRC= encode.c digest.c evp_enc.c evp_key.c evp_acnf.c evp_cnf.c \ |
| c_all.c c_allc.c c_alld.c evp_lib.c bio_ok.c \ |
| evp_pkey.c evp_pbe.c p5_crpt.c p5_crpt2.c \ |
| e_old.c pmeth_lib.c pmeth_fn.c pmeth_gn.c m_sigver.c evp_fips.c \ |
| - e_aes_cbc_hmac_sha1.c e_rc4_hmac_md5.c |
| + e_aes_cbc_hmac_sha1.c e_rc4_hmac_md5.c evp_aead.c |
| |
| LIBOBJ= encode.o digest.o evp_enc.o evp_key.o evp_acnf.o evp_cnf.o \ |
| e_des.o e_bf.o e_idea.o e_des3.o e_camellia.o\ |
| @@ -42,7 +42,7 @@ LIBOBJ= encode.o digest.o evp_enc.o evp_key.o evp_acnf.o evp_cnf.o \ |
| c_all.o c_allc.o c_alld.o evp_lib.o bio_ok.o \ |
| evp_pkey.o evp_pbe.o p5_crpt.o p5_crpt2.o \ |
| e_old.o pmeth_lib.o pmeth_fn.o pmeth_gn.o m_sigver.o evp_fips.o \ |
| - e_aes_cbc_hmac_sha1.o e_rc4_hmac_md5.o |
| + e_aes_cbc_hmac_sha1.o e_rc4_hmac_md5.o evp_aead.o |
| |
| SRC= $(LIBSRC) |
| |
| diff --git a/crypto/evp/e_aes.c b/crypto/evp/e_aes.c |
| index ef44f63..e4485e4 100644 |
| --- a/crypto/evp/e_aes.c |
| +++ b/crypto/evp/e_aes.c |
| @@ -814,44 +814,45 @@ static int aes_gcm_ctrl(EVP_CIPHER_CTX *c, int type, int arg, void *ptr) |
| } |
| } |
| |
| -static int aes_gcm_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key, |
| - const unsigned char *iv, int enc) |
| +static ctr128_f aes_gcm_set_key(AES_KEY *aes_key, GCM128_CONTEXT *gcm_ctx, |
| + const unsigned char *key, size_t key_len) |
| { |
| - EVP_AES_GCM_CTX *gctx = ctx->cipher_data; |
| - if (!iv && !key) |
| - return 1; |
| - if (key) |
| - { do { |
| #ifdef BSAES_CAPABLE |
| if (BSAES_CAPABLE) |
| { |
| - AES_set_encrypt_key(key,ctx->key_len*8,&gctx->ks); |
| - CRYPTO_gcm128_init(&gctx->gcm,&gctx->ks, |
| + AES_set_encrypt_key(key,key_len*8,aes_key); |
| + CRYPTO_gcm128_init(gcm_ctx,aes_key, |
| (block128_f)AES_encrypt); |
| - gctx->ctr = (ctr128_f)bsaes_ctr32_encrypt_blocks; |
| - break; |
| + return (ctr128_f)bsaes_ctr32_encrypt_blocks; |
| } |
| - else |
| #endif |
| #ifdef VPAES_CAPABLE |
| if (VPAES_CAPABLE) |
| { |
| - vpaes_set_encrypt_key(key,ctx->key_len*8,&gctx->ks); |
| - CRYPTO_gcm128_init(&gctx->gcm,&gctx->ks, |
| + vpaes_set_encrypt_key(key,key_len*8,aes_key); |
| + CRYPTO_gcm128_init(gcm_ctx,aes_key, |
| (block128_f)vpaes_encrypt); |
| - gctx->ctr = NULL; |
| - break; |
| + return NULL; |
| } |
| #endif |
| - AES_set_encrypt_key(key, ctx->key_len * 8, &gctx->ks); |
| - CRYPTO_gcm128_init(&gctx->gcm, &gctx->ks, (block128_f)AES_encrypt); |
| + AES_set_encrypt_key(key, key_len*8, aes_key); |
| + CRYPTO_gcm128_init(gcm_ctx, aes_key, (block128_f)AES_encrypt); |
| #ifdef AES_CTR_ASM |
| - gctx->ctr = (ctr128_f)AES_ctr32_encrypt; |
| + return (ctr128_f)AES_ctr32_encrypt; |
| #else |
| - gctx->ctr = NULL; |
| + return NULL; |
| #endif |
| - } while (0); |
| + } |
| |
| +static int aes_gcm_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key, |
| + const unsigned char *iv, int enc) |
| + { |
| + EVP_AES_GCM_CTX *gctx = ctx->cipher_data; |
| + if (!iv && !key) |
| + return 1; |
| + if (key) |
| + { |
| + gctx->ctr = aes_gcm_set_key(&gctx->ks, &gctx->gcm, key, ctx->key_len); |
| /* If we have an iv can set it directly, otherwise use |
| * saved IV. |
| */ |
| @@ -1310,5 +1311,176 @@ BLOCK_CIPHER_custom(NID_aes,128,1,12,ccm,CCM,EVP_CIPH_FLAG_FIPS|CUSTOM_FLAGS) |
| BLOCK_CIPHER_custom(NID_aes,192,1,12,ccm,CCM,EVP_CIPH_FLAG_FIPS|CUSTOM_FLAGS) |
| BLOCK_CIPHER_custom(NID_aes,256,1,12,ccm,CCM,EVP_CIPH_FLAG_FIPS|CUSTOM_FLAGS) |
| |
| +#define EVP_AEAD_AES_128_GCM_TAG_LEN 16 |
| + |
| +struct aead_aes_128_gcm_ctx { |
| + union { double align; AES_KEY ks; } ks; |
| + GCM128_CONTEXT gcm; |
| + ctr128_f ctr; |
| + unsigned char tag_len; |
| +}; |
| + |
| +static int aead_aes_128_gcm_init(EVP_AEAD_CTX *ctx, |
| + const unsigned char *key, size_t key_len, size_t tag_len) |
| + { |
| + struct aead_aes_128_gcm_ctx *gcm_ctx; |
| + |
| + if (key_len*8 != 128) |
| + { |
| + EVPerr(EVP_F_AEAD_AES_128_GCM_INIT, EVP_R_BAD_KEY_LENGTH); |
| + return 0; /* EVP_AEAD_CTX_init should catch this. */ |
| + } |
| + |
| + if (tag_len == EVP_AEAD_DEFAULT_TAG_LENGTH) |
| + tag_len = EVP_AEAD_AES_128_GCM_TAG_LEN; |
| + |
| + if (tag_len > EVP_AEAD_AES_128_GCM_TAG_LEN) |
| + { |
| + EVPerr(EVP_F_AEAD_AES_128_GCM_INIT, EVP_R_TAG_TOO_LARGE); |
| + return 0; |
| + } |
| + |
| + gcm_ctx = OPENSSL_malloc(sizeof(struct aead_aes_128_gcm_ctx)); |
| + if (gcm_ctx == NULL) |
| + return 0; |
| + |
| +#ifdef AESNI_CAPABLE |
| + if (AESNI_CAPABLE) |
| + { |
| + aesni_set_encrypt_key(key, key_len * 8, &gcm_ctx->ks.ks); |
| + CRYPTO_gcm128_init(&gcm_ctx->gcm, &gcm_ctx->ks.ks, |
| + (block128_f)aesni_encrypt); |
| + gcm_ctx->ctr = (ctr128_f) aesni_ctr32_encrypt_blocks; |
| + } |
| + else |
| +#endif |
| + { |
| + gcm_ctx->ctr = aes_gcm_set_key(&gcm_ctx->ks.ks, &gcm_ctx->gcm, |
| + key, key_len); |
| + } |
| + gcm_ctx->tag_len = tag_len; |
| + ctx->aead_state = gcm_ctx; |
| + |
| + return 1; |
| + } |
| + |
| +static void aead_aes_128_gcm_cleanup(EVP_AEAD_CTX *ctx) |
| + { |
| + struct aead_aes_128_gcm_ctx *gcm_ctx = ctx->aead_state; |
| + OPENSSL_free(gcm_ctx); |
| + } |
| + |
| +static ssize_t aead_aes_128_gcm_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) |
| + { |
| + size_t bulk = 0; |
| + const struct aead_aes_128_gcm_ctx *gcm_ctx = ctx->aead_state; |
| + GCM128_CONTEXT gcm; |
| + |
| + if (max_out_len < in_len + gcm_ctx->tag_len) |
| + { |
| + EVPerr(EVP_F_AEAD_AES_128_GCM_SEAL, EVP_R_BUFFER_TOO_SMALL); |
| + return -1; |
| + } |
| + |
| + memcpy(&gcm, &gcm_ctx->gcm, sizeof(gcm)); |
| + CRYPTO_gcm128_setiv(&gcm, nonce, nonce_len); |
| + |
| + if (ad_len > 0 && CRYPTO_gcm128_aad(&gcm, ad, ad_len)) |
| + return -1; |
| + |
| + if (gcm_ctx->ctr) |
| + { |
| + if (CRYPTO_gcm128_encrypt_ctr32(&gcm, in + bulk, out + bulk, |
| + in_len - bulk, gcm_ctx->ctr)) |
| + return -1; |
| + } |
| + else |
| + { |
| + if (CRYPTO_gcm128_encrypt(&gcm, in + bulk, out + bulk, |
| + in_len - bulk)) |
| + return -1; |
| + } |
| + |
| + CRYPTO_gcm128_tag(&gcm, out + in_len, gcm_ctx->tag_len); |
| + return in_len + gcm_ctx->tag_len; |
| + } |
| + |
| +static ssize_t aead_aes_128_gcm_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) |
| + { |
| + size_t bulk = 0; |
| + const struct aead_aes_128_gcm_ctx *gcm_ctx = ctx->aead_state; |
| + unsigned char tag[EVP_AEAD_AES_128_GCM_TAG_LEN]; |
| + size_t out_len; |
| + GCM128_CONTEXT gcm; |
| + |
| + if (in_len < gcm_ctx->tag_len) |
| + { |
| + EVPerr(EVP_F_AEAD_AES_128_GCM_OPEN, EVP_R_BAD_DECRYPT); |
| + return -1; |
| + } |
| + |
| + out_len = in_len - gcm_ctx->tag_len; |
| + |
| + if (max_out_len < out_len) |
| + { |
| + EVPerr(EVP_F_AEAD_AES_128_GCM_OPEN, EVP_R_BUFFER_TOO_SMALL); |
| + return -1; |
| + } |
| + |
| + memcpy(&gcm, &gcm_ctx->gcm, sizeof(gcm)); |
| + CRYPTO_gcm128_setiv(&gcm, nonce, nonce_len); |
| + |
| + if (CRYPTO_gcm128_aad(&gcm, ad, ad_len)) |
| + return -1; |
| + |
| + if (gcm_ctx->ctr) |
| + { |
| + if (CRYPTO_gcm128_decrypt_ctr32(&gcm, in + bulk, out + bulk, |
| + in_len-bulk-gcm_ctx->tag_len, |
| + gcm_ctx->ctr)) |
| + return -1; |
| + } |
| + else |
| + { |
| + if (CRYPTO_gcm128_decrypt(&gcm, in + bulk, out + bulk, |
| + in_len - bulk - gcm_ctx->tag_len)) |
| + return -1; |
| + } |
| + |
| + CRYPTO_gcm128_tag(&gcm, tag, gcm_ctx->tag_len); |
| + if (CRYPTO_memcmp(tag, in + out_len, gcm_ctx->tag_len) != 0) |
| + { |
| + EVPerr(EVP_F_AEAD_AES_128_GCM_OPEN, EVP_R_BAD_DECRYPT); |
| + return -1; |
| + } |
| + |
| + return out_len; |
| + } |
| + |
| +static const EVP_AEAD aead_aes_128_gcm = { |
| + 16, /* key len */ |
| + 12, /* nonce len */ |
| + EVP_AEAD_AES_128_GCM_TAG_LEN, /* overhead */ |
| + EVP_AEAD_AES_128_GCM_TAG_LEN, /* max tag length */ |
| + |
| + aead_aes_128_gcm_init, |
| + aead_aes_128_gcm_cleanup, |
| + aead_aes_128_gcm_seal, |
| + aead_aes_128_gcm_open, |
| +}; |
| + |
| +const EVP_AEAD *EVP_aead_aes_128_gcm() |
| + { |
| + return &aead_aes_128_gcm; |
| + } |
| + |
| #endif |
| #endif |
| diff --git a/crypto/evp/evp.h b/crypto/evp/evp.h |
| index 5f18d4b..bd10642 100644 |
| --- a/crypto/evp/evp.h |
| +++ b/crypto/evp/evp.h |
| @@ -1243,6 +1243,109 @@ void EVP_PKEY_meth_set_ctrl(EVP_PKEY_METHOD *pmeth, |
| int (*ctrl_str)(EVP_PKEY_CTX *ctx, |
| const char *type, const char *value)); |
| |
| +/* Authenticated Encryption with Additional Data. |
| + * |
| + * AEAD couples confidentiality and integrity in a single primtive. AEAD |
| + * algorithms take a key and then can seal and open individual messages. Each |
| + * message has a unique, per-message nonce and, optionally, additional data |
| + * which is authenticated but not included in the output. */ |
| + |
| +struct evp_aead_st; |
| +typedef struct evp_aead_st EVP_AEAD; |
| + |
| +#ifndef OPENSSL_NO_AES |
| +/* EVP_aes_128_gcm is AES-128 in Galois Counter Mode. */ |
| +const EVP_AEAD *EVP_aead_aes_128_gcm(void); |
| +#endif |
| + |
| +/* EVP_AEAD_key_length returns the length, in bytes, of the keys used by |
| + * |aead|. */ |
| +size_t EVP_AEAD_key_length(const EVP_AEAD *aead); |
| + |
| +/* EVP_AEAD_nonce_length returns the length, in bytes, of the per-message nonce |
| + * for |aead|. */ |
| +size_t EVP_AEAD_nonce_length(const EVP_AEAD *aead); |
| + |
| +/* EVP_AEAD_max_overhead returns the maximum number of additional bytes added |
| + * by the act of sealing data with |aead|. */ |
| +size_t EVP_AEAD_max_overhead(const EVP_AEAD *aead); |
| + |
| +/* EVP_AEAD_max_tag_len returns the maximum tag length when using |aead|. This |
| + * is the largest value that can be passed as |tag_len| to |
| + * |EVP_AEAD_CTX_init|. */ |
| +size_t EVP_AEAD_max_tag_len(const EVP_AEAD *aead); |
| + |
| +/* An EVP_AEAD_CTX represents an AEAD algorithm configured with a specific key |
| + * and message-independent IV. */ |
| +typedef struct evp_aead_ctx_st { |
| + const EVP_AEAD *aead; |
| + /* aead_state is an opaque pointer to whatever state the AEAD needs to |
| + * maintain. */ |
| + void *aead_state; |
| +} EVP_AEAD_CTX; |
| + |
| +#define EVP_AEAD_DEFAULT_TAG_LENGTH 0 |
| + |
| +/* EVP_AEAD_init initializes |ctx| for the given AEAD algorithm from |impl|. |
| + * The |impl| argument may be NULL to choose the default implementation. |
| + * Authentication tags may be truncated by passing a size as |tag_len|. A |
| + * |tag_len| of zero indicates the default tag length and this is defined as |
| + * EVP_AEAD_DEFAULT_TAG_LENGTH for readability. |
| + * Returns 1 on success. Otherwise returns 0 and pushes to the error stack. */ |
| +int EVP_AEAD_CTX_init(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead, |
| + const unsigned char *key, size_t key_len, |
| + size_t tag_len, ENGINE *impl); |
| + |
| +/* EVP_AEAD_CTX_cleanup frees any data allocated by |ctx|. */ |
| +void EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX *ctx); |
| + |
| +/* EVP_AEAD_CTX_seal encrypts and authenticates |in_len| bytes from |in| and |
| + * authenticates |ad_len| bytes from |ad| and writes the result to |out|, |
| + * returning the number of bytes written, or -1 on error. |
| + * |
| + * This function may be called (with the same EVP_AEAD_CTX) concurrently with |
| + * itself or EVP_AEAD_CTX_open. |
| + * |
| + * At most |max_out_len| bytes are written to |out| and, in order to ensure |
| + * success, |max_out_len| should be |in_len| plus the result of |
| + * EVP_AEAD_overhead. |
| + * |
| + * The length of |nonce|, |nonce_len|, must be equal to the result of |
| + * EVP_AEAD_nonce_length for this AEAD. |
| + * |
| + * EVP_AEAD_CTX_seal never results in a partial output. If |max_out_len| is |
| + * insufficient, -1 will be returned. |
| + * |
| + * If |in| and |out| alias then |out| must be <= |in|. */ |
| +ssize_t EVP_AEAD_CTX_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); |
| + |
| +/* EVP_AEAD_CTX_open authenticates |in_len| bytes from |in| and |ad_len| bytes |
| + * from |ad| and decrypts at most |in_len| bytes into |out|. It returns the |
| + * number of bytes written, or -1 on error. |
| + * |
| + * This function may be called (with the same EVP_AEAD_CTX) concurrently with |
| + * itself or EVP_AEAD_CTX_seal. |
| + * |
| + * At most |in_len| bytes are written to |out|. In order to ensure success, |
| + * |max_out_len| should be at least |in_len|. |
| + * |
| + * The length of |nonce|, |nonce_len|, must be equal to the result of |
| + * EVP_AEAD_nonce_length for this AEAD. |
| + * |
| + * EVP_AEAD_CTX_open never results in a partial output. If |max_out_len| is |
| + * insufficient, -1 will be returned. |
| + * |
| + * If |in| and |out| alias then |out| must be <= |in|. */ |
| +ssize_t EVP_AEAD_CTX_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); |
| + |
| void EVP_add_alg_module(void); |
| |
| /* BEGIN ERROR CODES */ |
| @@ -1254,6 +1357,11 @@ void ERR_load_EVP_strings(void); |
| /* Error codes for the EVP functions. */ |
| |
| /* Function codes. */ |
| +#define EVP_F_AEAD_AES_128_GCM_INIT 183 |
| +#define EVP_F_AEAD_AES_128_GCM_OPEN 181 |
| +#define EVP_F_AEAD_AES_128_GCM_SEAL 182 |
| +#define EVP_F_AEAD_CTX_OPEN 185 |
| +#define EVP_F_AEAD_CTX_SEAL 186 |
| #define EVP_F_AESNI_INIT_KEY 165 |
| #define EVP_F_AESNI_XTS_CIPHER 176 |
| #define EVP_F_AES_INIT_KEY 133 |
| @@ -1268,6 +1376,7 @@ void ERR_load_EVP_strings(void); |
| #define EVP_F_DSA_PKEY2PKCS8 135 |
| #define EVP_F_ECDSA_PKEY2PKCS8 129 |
| #define EVP_F_ECKEY_PKEY2PKCS8 132 |
| +#define EVP_F_EVP_AEAD_CTX_INIT 180 |
| #define EVP_F_EVP_CIPHERINIT_EX 123 |
| #define EVP_F_EVP_CIPHER_CTX_COPY 163 |
| #define EVP_F_EVP_CIPHER_CTX_CTRL 124 |
| @@ -1383,10 +1492,12 @@ void ERR_load_EVP_strings(void); |
| #define EVP_R_NO_VERIFY_FUNCTION_CONFIGURED 105 |
| #define EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE 150 |
| #define EVP_R_OPERATON_NOT_INITIALIZED 151 |
| +#define EVP_R_OUTPUT_ALIASES_INPUT 170 |
| #define EVP_R_PKCS8_UNKNOWN_BROKEN_TYPE 117 |
| #define EVP_R_PRIVATE_KEY_DECODE_ERROR 145 |
| #define EVP_R_PRIVATE_KEY_ENCODE_ERROR 146 |
| #define EVP_R_PUBLIC_KEY_NOT_RSA 106 |
| +#define EVP_R_TAG_TOO_LARGE 171 |
| #define EVP_R_TOO_LARGE 164 |
| #define EVP_R_UNKNOWN_CIPHER 160 |
| #define EVP_R_UNKNOWN_DIGEST 161 |
| diff --git a/crypto/evp/evp_aead.c b/crypto/evp/evp_aead.c |
| new file mode 100644 |
| index 0000000..91da561 |
| --- /dev/null |
| +++ b/crypto/evp/evp_aead.c |
| @@ -0,0 +1,192 @@ |
| +/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
| + * All rights reserved. |
| + * |
| + * This package is an SSL implementation written |
| + * by Eric Young (eay@cryptsoft.com). |
| + * The implementation was written so as to conform with Netscapes SSL. |
| + * |
| + * This library is free for commercial and non-commercial use as long as |
| + * the following conditions are aheared to. The following conditions |
| + * apply to all code found in this distribution, be it the RC4, RSA, |
| + * lhash, DES, etc., code; not just the SSL code. The SSL documentation |
| + * included with this distribution is covered by the same copyright terms |
| + * except that the holder is Tim Hudson (tjh@cryptsoft.com). |
| + * |
| + * Copyright remains Eric Young's, and as such any Copyright notices in |
| + * the code are not to be removed. |
| + * If this package is used in a product, Eric Young should be given attribution |
| + * as the author of the parts of the library used. |
| + * This can be in the form of a textual message at program startup or |
| + * in documentation (online or textual) provided with the package. |
| + * |
| + * 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 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 acknowledgement: |
| + * "This product includes cryptographic software written by |
| + * Eric Young (eay@cryptsoft.com)" |
| + * The word 'cryptographic' can be left out if the rouines from the library |
| + * being used are not cryptographic related :-). |
| + * 4. If you include any Windows specific code (or a derivative thereof) from |
| + * the apps directory (application code) you must include an acknowledgement: |
| + * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" |
| + * |
| + * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND |
| + * ANY EXPRESS 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 AUTHOR OR 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. |
| + * |
| + * The licence and distribution terms for any publically available version or |
| + * derivative of this code cannot be changed. i.e. this code cannot simply be |
| + * copied and put under another distribution licence |
| + * [including the GNU Public Licence.] |
| + */ |
| + |
| +#include <limits.h> |
| +#include <string.h> |
| + |
| +#include <openssl/evp.h> |
| +#include <openssl/err.h> |
| + |
| +#include "evp_locl.h" |
| + |
| +size_t EVP_AEAD_key_length(const EVP_AEAD *aead) |
| + { |
| + return aead->key_len; |
| + } |
| + |
| +size_t EVP_AEAD_nonce_length(const EVP_AEAD *aead) |
| + { |
| + return aead->nonce_len; |
| + } |
| + |
| +size_t EVP_AEAD_max_overhead(const EVP_AEAD *aead) |
| + { |
| + return aead->overhead; |
| + } |
| + |
| +size_t EVP_AEAD_max_tag_len(const EVP_AEAD *aead) |
| + { |
| + return aead->max_tag_len; |
| + } |
| + |
| +int EVP_AEAD_CTX_init(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead, |
| + const unsigned char *key, size_t key_len, |
| + size_t tag_len, ENGINE *impl) |
| + { |
| + ctx->aead = aead; |
| + if (key_len != aead->key_len) |
| + { |
| + EVPerr(EVP_F_EVP_AEAD_CTX_INIT,EVP_R_UNSUPPORTED_KEY_SIZE); |
| + return 0; |
| + } |
| + return aead->init(ctx, key, key_len, tag_len); |
| + } |
| + |
| +void EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX *ctx) |
| + { |
| + if (ctx->aead == NULL) |
| + return; |
| + ctx->aead->cleanup(ctx); |
| + ctx->aead = NULL; |
| + } |
| + |
| +/* check_alias returns 0 if |out| points within the buffer determined by |in| |
| + * and |in_len| and 1 otherwise. |
| + * |
| + * When processing, there's only an issue if |out| points within in[:in_len] |
| + * and isn't equal to |in|. If that's the case then writing the output will |
| + * stomp input that hasn't been read yet. |
| + * |
| + * This function checks for that case. */ |
| +static int check_alias(const unsigned char *in, size_t in_len, |
| + const unsigned char *out) |
| + { |
| + if (out <= in) |
| + return 1; |
| + if (in + in_len <= out) |
| + return 1; |
| + return 0; |
| + } |
| + |
| +ssize_t EVP_AEAD_CTX_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) |
| + { |
| + size_t possible_out_len = in_len + ctx->aead->overhead; |
| + ssize_t r; |
| + |
| + if (possible_out_len < in_len /* overflow */ || |
| + possible_out_len > SSIZE_MAX /* return value cannot be |
| + represented */) |
| + { |
| + EVPerr(EVP_F_AEAD_CTX_SEAL, EVP_R_TOO_LARGE); |
| + goto error; |
| + } |
| + |
| + if (!check_alias(in, in_len, out)) |
| + { |
| + EVPerr(EVP_F_AEAD_CTX_SEAL, EVP_R_OUTPUT_ALIASES_INPUT); |
| + goto error; |
| + } |
| + |
| + r = ctx->aead->seal(ctx, out, max_out_len, nonce, nonce_len, |
| + in, in_len, ad, ad_len); |
| + if (r >= 0) |
| + return r; |
| + |
| +error: |
| + /* In the event of an error, clear the output buffer so that a caller |
| + * that doesn't check the return value doesn't send raw data. */ |
| + memset(out, 0, max_out_len); |
| + return -1; |
| + } |
| + |
| +ssize_t EVP_AEAD_CTX_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) |
| + { |
| + ssize_t r; |
| + |
| + if (in_len > SSIZE_MAX) |
| + { |
| + EVPerr(EVP_F_AEAD_CTX_OPEN, EVP_R_TOO_LARGE); |
| + goto error; /* may not be able to represent return value. */ |
| + } |
| + |
| + if (!check_alias(in, in_len, out)) |
| + { |
| + EVPerr(EVP_F_AEAD_CTX_OPEN, EVP_R_OUTPUT_ALIASES_INPUT); |
| + goto error; |
| + } |
| + |
| + r = ctx->aead->open(ctx, out, max_out_len, nonce, nonce_len, |
| + in, in_len, ad, ad_len); |
| + |
| + if (r >= 0) |
| + return r; |
| + |
| +error: |
| + /* In the event of an error, clear the output buffer so that a caller |
| + * that doesn't check the return value doesn't try and process bad |
| + * data. */ |
| + memset(out, 0, max_out_len); |
| + return -1; |
| + } |
| diff --git a/crypto/evp/evp_err.c b/crypto/evp/evp_err.c |
| index 08eab98..c47969c 100644 |
| --- a/crypto/evp/evp_err.c |
| +++ b/crypto/evp/evp_err.c |
| @@ -70,6 +70,11 @@ |
| |
| static ERR_STRING_DATA EVP_str_functs[]= |
| { |
| +{ERR_FUNC(EVP_F_AEAD_AES_128_GCM_INIT), "AEAD_AES_128_GCM_INIT"}, |
| +{ERR_FUNC(EVP_F_AEAD_AES_128_GCM_OPEN), "AEAD_AES_128_GCM_OPEN"}, |
| +{ERR_FUNC(EVP_F_AEAD_AES_128_GCM_SEAL), "AEAD_AES_128_GCM_SEAL"}, |
| +{ERR_FUNC(EVP_F_AEAD_CTX_OPEN), "AEAD_CTX_OPEN"}, |
| +{ERR_FUNC(EVP_F_AEAD_CTX_SEAL), "AEAD_CTX_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"}, |
| @@ -84,6 +89,7 @@ static ERR_STRING_DATA EVP_str_functs[]= |
| {ERR_FUNC(EVP_F_DSA_PKEY2PKCS8), "DSA_PKEY2PKCS8"}, |
| {ERR_FUNC(EVP_F_ECDSA_PKEY2PKCS8), "ECDSA_PKEY2PKCS8"}, |
| {ERR_FUNC(EVP_F_ECKEY_PKEY2PKCS8), "ECKEY_PKEY2PKCS8"}, |
| +{ERR_FUNC(EVP_F_EVP_AEAD_CTX_INIT), "EVP_AEAD_CTX_init"}, |
| {ERR_FUNC(EVP_F_EVP_CIPHERINIT_EX), "EVP_CipherInit_ex"}, |
| {ERR_FUNC(EVP_F_EVP_CIPHER_CTX_COPY), "EVP_CIPHER_CTX_copy"}, |
| {ERR_FUNC(EVP_F_EVP_CIPHER_CTX_CTRL), "EVP_CIPHER_CTX_ctrl"}, |
| @@ -202,10 +208,12 @@ static ERR_STRING_DATA EVP_str_reasons[]= |
| {ERR_REASON(EVP_R_NO_VERIFY_FUNCTION_CONFIGURED),"no verify function configured"}, |
| {ERR_REASON(EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE),"operation not supported for this keytype"}, |
| {ERR_REASON(EVP_R_OPERATON_NOT_INITIALIZED),"operaton not initialized"}, |
| +{ERR_REASON(EVP_R_OUTPUT_ALIASES_INPUT) ,"output aliases input"}, |
| {ERR_REASON(EVP_R_PKCS8_UNKNOWN_BROKEN_TYPE),"pkcs8 unknown broken type"}, |
| {ERR_REASON(EVP_R_PRIVATE_KEY_DECODE_ERROR),"private key decode error"}, |
| {ERR_REASON(EVP_R_PRIVATE_KEY_ENCODE_ERROR),"private key encode error"}, |
| {ERR_REASON(EVP_R_PUBLIC_KEY_NOT_RSA) ,"public key not rsa"}, |
| +{ERR_REASON(EVP_R_TAG_TOO_LARGE) ,"tag too large"}, |
| {ERR_REASON(EVP_R_TOO_LARGE) ,"too large"}, |
| {ERR_REASON(EVP_R_UNKNOWN_CIPHER) ,"unknown cipher"}, |
| {ERR_REASON(EVP_R_UNKNOWN_DIGEST) ,"unknown digest"}, |
| diff --git a/crypto/evp/evp_locl.h b/crypto/evp/evp_locl.h |
| index 08c0a66..c0f9fdf 100644 |
| --- a/crypto/evp/evp_locl.h |
| +++ b/crypto/evp/evp_locl.h |
| @@ -348,6 +348,30 @@ int PKCS5_v2_PBKDF2_keyivgen(EVP_CIPHER_CTX *ctx, const char *pass, int passlen, |
| ASN1_TYPE *param, |
| const EVP_CIPHER *c, const EVP_MD *md, int en_de); |
| |
| +/* EVP_AEAD represents a specific AEAD algorithm. */ |
| +struct evp_aead_st { |
| + unsigned char key_len; |
| + unsigned char nonce_len; |
| + unsigned char overhead; |
| + unsigned char max_tag_len; |
| + |
| + int (*init) (struct evp_aead_ctx_st*, const unsigned char *key, |
| + size_t key_len, size_t tag_len); |
| + void (*cleanup) (struct evp_aead_ctx_st*); |
| + |
| + ssize_t (*seal) (const struct evp_aead_ctx_st *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); |
| + |
| + ssize_t (*open) (const struct evp_aead_ctx_st *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); |
| +}; |
| + |
| #ifdef OPENSSL_FIPS |
| |
| #ifdef OPENSSL_DOING_MAKEDEPEND |
| diff --git a/doc/crypto/EVP_AEAD_CTX_init.pod b/doc/crypto/EVP_AEAD_CTX_init.pod |
| new file mode 100644 |
| index 0000000..20e455d |
| --- /dev/null |
| +++ b/doc/crypto/EVP_AEAD_CTX_init.pod |
| @@ -0,0 +1,96 @@ |
| +=pod |
| + |
| +=head1 NAME |
| + |
| +EVP_AEAD_CTX_init, EVP_AEAD_CTX_cleanup, EVP_AEAD_CTX_seal, EVP_AEAD_CTX_open - authenticated encryption functions. |
| + |
| +=head1 SYNOPSIS |
| + |
| + #include <openssl/evp.h> |
| + |
| + int EVP_AEAD_CTX_init(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead, |
| + const unsigned char *key, size_t key_len, |
| + size_t tag_len, ENGINE *impl); |
| + void EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX *ctx); |
| + ssize_t EVP_AEAD_CTX_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); |
| + ssize_t EVP_AEAD_CTX_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); |
| + |
| +=head1 DESCRIPTION |
| + |
| +The EVP_AEAD_CTX_init() function initialises an B<EVP_AEAD_CTX> structure and |
| +performs any precomputation needed to use B<aead> with B<key>. The length of |
| +the key, B<key_len>, is given in bytes. |
| + |
| +The B<tag_len> argument contains the length of the tags, in bytes, and allows |
| +for the processing of truncated authenticators. A zero value indicates that the |
| +default tag length should be used and this is defined as |
| +C<EVP_AEAD_DEFAULT_TAG_LENGTH> in order to make the code clear. Using truncated |
| +tags increases an attacker's chance of creating a valid forgery. Be aware that |
| +the attacker's chance may increase more than exponentially as would naively be |
| +expected. |
| + |
| +When no longer needed, the initialised B<EVP_AEAD_CTX> structure must be passed |
| +to EVP_AEAD_CTX_cleanup(), which will deallocate any memory used. |
| + |
| +With an B<EVP_AEAD_CTX> in hand, one can seal and open messages. These |
| +operations are intended to meet the standard notions of privacy and |
| +authenticity for authenticated encryption. For formal definitions see I<Bellare |
| +and Namprempre>, "Authenticated encryption: relations among notions and |
| +analysis of the generic composition paradigm," Lecture Notes in Computer |
| +Science B<1976> (2000), 531–545, |
| +L<http://www-cse.ucsd.edu/~mihir/papers/oem.html>. |
| + |
| +When sealing messages, a nonce must be given. The length of the nonce is fixed |
| +by the AEAD in use and is returned by EVP_AEAD_nonce_length(). I<The nonce must |
| +be unique for all messages with the same key>. This is critically important - |
| +nonce reuse may completely undermine the security of the AEAD. Nonces may be |
| +predictable and public, so long as they are unique. Uniqueness may be achieved |
| +with a simple counter or, if long enough, may be generated randomly. The nonce |
| +must be passed into the "open" operation by the receiver so must either be |
| +implicit (e.g. a counter), or must be transmitted along with the sealed message. |
| + |
| +The "seal" and "open" operations are atomic - an entire message must be |
| +encrypted or decrypted in a single call. Large messages may have to be split up |
| +in order to accomodate this. When doing so, be mindful of the need not to |
| +repeat nonces and the possibility that an attacker could duplicate, reorder or |
| +drop message chunks. For example, using a single key for a given (large) |
| +message and sealing chunks with nonces counting from zero would be secure as |
| +long as the number of chunks was securely transmitted. (Otherwise an attacker |
| +could truncate the message by dropping chunks from the end.) |
| + |
| +The number of chunks could be transmitted by prefixing it to the plaintext, for |
| +example. This also assumes that no other message would ever use the same key |
| +otherwise the rule that nonces must be unique for a given key would be |
| +violated. |
| + |
| +The "seal" and "open" operations also permit additional data to be |
| +authenticated via the B<ad> parameter. This data is not included in the |
| +ciphertext and must be identical for both the "seal" and "open" call. This |
| +permits implicit context to be authenticated but may be C<NULL> if not needed. |
| + |
| +The "seal" and "open" operations may work inplace if the B<out> and B<in> |
| +arguments are equal. They may also be used to shift the data left inside the |
| +same buffer if B<out> is less than B<in>. However, B<out> may not point inside |
| +the input data otherwise the input may be overwritten before it has been read. |
| +This case will cause an error. |
| + |
| +=head1 RETURN VALUES |
| + |
| +The "seal" and "open" operations return an C<ssize_t> with value -1 on error, |
| +otherwise they return the number of output bytes written. An error will be |
| +returned if the input length is large enough that the output size exceeds the |
| +range of a C<ssize_t>. |
| + |
| +=head1 HISTORY |
| + |
| +These functions were first added to OpenSSL 1.0.2. |
| + |
| +=cut |
| -- |
| 1.8.4.1 |
| |