path: root/providers/default/ciphers/cipher_aes_ocb.c

/*
 * Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (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 "cipher_aes_ocb.h"
#include "internal/providercommonerr.h"
#include "internal/ciphers/cipher_aead.h"
#include "internal/provider_algs.h"

#define AES_OCB_FLAGS AEAD_FLAGS

#define OCB_DEFAULT_TAG_LEN 16
#define OCB_DEFAULT_IV_LEN  12
#define OCB_MIN_IV_LEN      1
#define OCB_MAX_IV_LEN      15

PROV_CIPHER_FUNC(int, ocb_cipher, (PROV_AES_OCB_CTX *ctx,
                                   const unsigned char *in, unsigned char *out,
                                   size_t nextblock));
/* forward declarations */
static OSSL_OP_cipher_encrypt_init_fn aes_ocb_einit;
static OSSL_OP_cipher_decrypt_init_fn aes_ocb_dinit;
static OSSL_OP_cipher_update_fn aes_ocb_block_update;
static OSSL_OP_cipher_final_fn aes_ocb_block_final;
static OSSL_OP_cipher_cipher_fn aes_ocb_cipher;
static OSSL_OP_cipher_freectx_fn aes_ocb_freectx;
static OSSL_OP_cipher_dupctx_fn aes_ocb_dupctx;
static OSSL_OP_cipher_get_ctx_params_fn aes_ocb_get_ctx_params;
static OSSL_OP_cipher_set_ctx_params_fn aes_ocb_set_ctx_params;

/*
 * The following methods could be moved into PROV_AES_OCB_HW if
 * multiple hardware implementations are ever needed.
 */
static ossl_inline int aes_generic_ocb_setiv(PROV_AES_OCB_CTX *ctx,
                                             const unsigned char *iv,
                                             size_t ivlen, size_t taglen)
{
    return (CRYPTO_ocb128_setiv(&ctx->ocb, iv, ivlen, taglen) == 1);
}

static ossl_inline int aes_generic_ocb_setaad(PROV_AES_OCB_CTX *ctx,
                                              const unsigned char *aad,
                                              size_t alen)
{
    return CRYPTO_ocb128_aad(&ctx->ocb, aad, alen) == 1;
}

static ossl_inline int aes_generic_ocb_gettag(PROV_AES_OCB_CTX *ctx,
                                              unsigned char *tag, size_t tlen)
{
    return CRYPTO_ocb128_tag(&ctx->ocb, tag, tlen) > 0;
}

static ossl_inline int aes_generic_ocb_final(PROV_AES_OCB_CTX *ctx)
{
    return (CRYPTO_ocb128_finish(&ctx->ocb, ctx->tag, ctx->taglen) == 0);
}

static ossl_inline void aes_generic_ocb_cleanup(PROV_AES_OCB_CTX *ctx)
{
    CRYPTO_ocb128_cleanup(&ctx->ocb);
}

static ossl_inline int aes_generic_ocb_cipher(PROV_AES_OCB_CTX *ctx,
                                              const unsigned char *in,
                                              unsigned char *out, size_t len)
{
    if (ctx->base.enc) {
        if (!CRYPTO_ocb128_encrypt(&ctx->ocb, in, out, len))
            return 0;
    } else {
        if (!CRYPTO_ocb128_decrypt(&ctx->ocb, in, out, len))
            return 0;
    }
    return 1;
}

static ossl_inline int aes_generic_ocb_copy_ctx(PROV_AES_OCB_CTX *dst,
                                                PROV_AES_OCB_CTX *src)
{
    return (!CRYPTO_ocb128_copy_ctx(&dst->ocb, &src->ocb,
                                    &src->ksenc.ks, &src->ksdec.ks));
}

/*-
 * Provider dispatch functions
 */
static int aes_ocb_init(void *vctx, const unsigned char *key, size_t keylen,
                        const unsigned char *iv, size_t ivlen, int enc)
{
   PROV_AES_OCB_CTX *ctx = (PROV_AES_OCB_CTX *)vctx;

   ctx->base.enc = enc;

   if (iv != NULL) {
       if (ivlen != ctx->base.ivlen) {
           /* IV len must be 1 to 15 */
           if (ivlen < OCB_MIN_IV_LEN || ivlen > OCB_MAX_IV_LEN) {
               ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
               return 0;
           }
           ctx->base.ivlen = ivlen;
       }
       memcpy(ctx->base.iv, iv, ivlen);
       ctx->iv_state = IV_STATE_BUFFERED;
   }
   if (key != NULL) {
       if (keylen != ctx->base.keylen) {
           ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
           return 0;
       }
       return ctx->base.hw->init(&ctx->base, key, keylen);
   }
   return 1;
}

static int aes_ocb_einit(void *vctx, const unsigned char *key, size_t keylen,
                         const unsigned char *iv, size_t ivlen)
{
    return aes_ocb_init(vctx, key, keylen, iv, ivlen, 1);
}

static int aes_ocb_dinit(void *vctx, const unsigned char *key, size_t keylen,
                         const unsigned char *iv, size_t ivlen)
{
    return aes_ocb_init(vctx, key, keylen, iv, ivlen, 0);
}

/*
 * Because of the way OCB works, both the AAD and data are buffered in the
 * same way. Only the last block can be a partial block.
 */
static int aes_ocb_block_update_internal(PROV_AES_OCB_CTX *ctx,
                                         unsigned char *buf, size_t *bufsz,
                                         unsigned char *out, size_t *outl,
                                         size_t outsize, const unsigned char *in,
                                         size_t inl, OSSL_ocb_cipher_fn ciph)
{
    size_t nextblocks = fillblock(buf, bufsz, AES_BLOCK_SIZE, &in, &inl);
    size_t outlint = 0;

    if (*bufsz == AES_BLOCK_SIZE) {
        if (outsize < AES_BLOCK_SIZE) {
            ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
            return 0;
        }
        if (!ciph(ctx, buf, out, AES_BLOCK_SIZE)) {
            ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
            return 0;
        }
        *bufsz = 0;
        outlint = AES_BLOCK_SIZE;
        out += AES_BLOCK_SIZE;
    }
    if (nextblocks > 0) {
        outlint += nextblocks;
        if (outsize < outlint) {
            ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
            return 0;
        }
        if (!ciph(ctx, in, out, nextblocks)) {
            ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
            return 0;
        }
        in += nextblocks;
        inl -= nextblocks;
    }
    if (!trailingdata(buf, bufsz, AES_BLOCK_SIZE, &in, &inl)) {
        /* PROVerr already called */
        return 0;
    }

    *outl = outlint;
    return inl == 0;
}

/* A wrapper function that has the same signature as cipher */
static int cipher_updateaad(PROV_AES_OCB_CTX *ctx, const unsigned char *in,
                            unsigned char *out, size_t len)
{
    return aes_generic_ocb_setaad(ctx, in, len);
}

static int update_iv(PROV_AES_OCB_CTX *ctx)
{
    if (ctx->iv_state == IV_STATE_FINISHED
        || ctx->iv_state == IV_STATE_UNINITIALISED)
        return 0;
    if (ctx->iv_state == IV_STATE_BUFFERED) {
        if (!aes_generic_ocb_setiv(ctx, ctx