Coverage Report

Created: 2024-11-21 07:03

/src/openssl/crypto/cmac/cmac.c
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Source (jump to first uncovered line)
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/*
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 * Copyright 2010-2024 The OpenSSL Project Authors. All Rights Reserved.
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 *
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 * Licensed under the Apache License 2.0 (the "License").  You may not use
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 * this file except in compliance with the License.  You can obtain a copy
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 * in the file LICENSE in the source distribution or at
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 * https://www.openssl.org/source/license.html
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 */
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/*
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 * CMAC low level APIs are deprecated for public use, but still ok for internal
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 * use.
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 */
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#include "internal/deprecated.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "internal/cryptlib.h"
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#include <openssl/cmac.h>
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#include <openssl/err.h>
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#include "crypto/cmac.h"
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8.87k
#define LOCAL_BUF_SIZE 2048
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struct CMAC_CTX_st {
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    /* Cipher context to use */
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    EVP_CIPHER_CTX *cctx;
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    /* Keys k1 and k2 */
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    unsigned char k1[EVP_MAX_BLOCK_LENGTH];
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    unsigned char k2[EVP_MAX_BLOCK_LENGTH];
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    /* Temporary block */
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    unsigned char tbl[EVP_MAX_BLOCK_LENGTH];
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    /* Last (possibly partial) block */
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    unsigned char last_block[EVP_MAX_BLOCK_LENGTH];
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    /* Number of bytes in last block: -1 means context not initialised */
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    int nlast_block;
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};
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/* Make temporary keys K1 and K2 */
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static void make_kn(unsigned char *k1, const unsigned char *l, int bl)
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7.24k
{
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7.24k
    int i;
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7.24k
    unsigned char c = l[0], carry = c >> 7, cnext;
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    /* Shift block to left, including carry */
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39.6k
    for (i = 0; i < bl - 1; i++, c = cnext)
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32.3k
        k1[i] = (c << 1) | ((cnext = l[i + 1]) >> 7);
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    /* If MSB set fixup with R */
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7.24k
    k1[i] = (c << 1) ^ ((0 - carry) & (bl == 16 ? 0x87 : 0x1b));
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7.24k
}
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CMAC_CTX *CMAC_CTX_new(void)
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137k
{
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137k
    CMAC_CTX *ctx;
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137k
    if ((ctx = OPENSSL_malloc(sizeof(*ctx))) == NULL)
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0
        return NULL;
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137k
    ctx->cctx = EVP_CIPHER_CTX_new();
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137k
    if (ctx->cctx == NULL) {
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0
        OPENSSL_free(ctx);
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0
        return NULL;
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0
    }
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137k
    ctx->nlast_block = -1;
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137k
    return ctx;
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137k
}
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void CMAC_CTX_cleanup(CMAC_CTX *ctx)
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137k
{
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137k
    EVP_CIPHER_CTX_reset(ctx->cctx);
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137k
    OPENSSL_cleanse(ctx->tbl, EVP_MAX_BLOCK_LENGTH);
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137k
    OPENSSL_cleanse(ctx->k1, EVP_MAX_BLOCK_LENGTH);
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137k
    OPENSSL_cleanse(ctx->k2, EVP_MAX_BLOCK_LENGTH);
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137k
    OPENSSL_cleanse(ctx->last_block, EVP_MAX_BLOCK_LENGTH);
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137k
    ctx->nlast_block = -1;
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137k
}
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EVP_CIPHER_CTX *CMAC_CTX_get0_cipher_ctx(CMAC_CTX *ctx)
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0
{
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0
    return ctx->cctx;
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0
}
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void CMAC_CTX_free(CMAC_CTX *ctx)
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137k
{
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137k
    if (!ctx)
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0
        return;
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137k
    CMAC_CTX_cleanup(ctx);
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137k
    EVP_CIPHER_CTX_free(ctx->cctx);
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137k
    OPENSSL_free(ctx);
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137k
}
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int CMAC_CTX_copy(CMAC_CTX *out, const CMAC_CTX *in)
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129k
{
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129k
    int bl;
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129k
    if (in->nlast_block == -1)
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8.39k
        return 0;
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121k
    if ((bl = EVP_CIPHER_CTX_get_block_size(in->cctx)) == 0)
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0
        return 0;
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121k
    if (!EVP_CIPHER_CTX_copy(out->cctx, in->cctx))
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0
        return 0;
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121k
    memcpy(out->k1, in->k1, bl);
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121k
    memcpy(out->k2, in->k2, bl);
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121k
    memcpy(out->tbl, in->tbl, bl);
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121k
    memcpy(out->last_block, in->last_block, bl);
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121k
    out->nlast_block = in->nlast_block;
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121k
    return 1;
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121k
}
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int ossl_cmac_init(CMAC_CTX *ctx, const void *key, size_t keylen,
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                   const EVP_CIPHER *cipher, ENGINE *impl,
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                   const OSSL_PARAM param[])
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7.33k
{
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7.33k
    static const unsigned char zero_iv[EVP_MAX_BLOCK_LENGTH] = { 0 };
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7.33k
    int block_len;
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    /* All zeros means restart */
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7.33k
    if (!key && !cipher && !impl && keylen == 0) {
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        /* Not initialised */
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0
        if (ctx->nlast_block == -1)
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0
            return 0;
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0
        if (!EVP_EncryptInit_ex2(ctx->cctx, NULL, NULL, zero_iv, param))
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0
            return 0;
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0
        block_len = EVP_CIPHER_CTX_get_block_size(ctx->cctx);
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0
        if (block_len == 0)
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0
            return 0;
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0
        memset(ctx->tbl, 0, block_len);
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0
        ctx->nlast_block = 0;
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0
        return 1;
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0
    }
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    /* Initialise context */
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7.33k
    if (cipher != NULL) {
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        /* Ensure we can't use this ctx until we also have a key */
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7.33k
        ctx->nlast_block = -1;
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7.33k
        if (impl != NULL) {
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0
            if (!EVP_EncryptInit_ex(ctx->cctx, cipher, impl, NULL, NULL))
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0
                return 0;
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7.33k
        } else {
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7.33k
            if (!EVP_EncryptInit_ex2(ctx->cctx, cipher, NULL, NULL, param))
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1.40k
                return 0;
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7.33k
        }
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7.33k
    }
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    /* Non-NULL key means initialisation complete */
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5.92k
    if (key != NULL) {
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4.78k
        int bl;
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        /* If anything fails then ensure we can't use this ctx */
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4.78k
        ctx->nlast_block = -1;
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4.78k
        if (EVP_CIPHER_CTX_get0_cipher(ctx->cctx) == NULL)
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0
            return 0;
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4.78k
        if (EVP_CIPHER_CTX_set_key_length(ctx->cctx, keylen) <= 0)
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1.15k
            return 0;
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3.62k
        if (!EVP_EncryptInit_ex2(ctx->cctx, NULL, key, zero_iv, param))
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0
            return 0;
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3.62k
        if ((bl = EVP_CIPHER_CTX_get_block_size(ctx->cctx)) < 0)
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0
            return 0;
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3.62k
        if (EVP_Cipher(ctx->cctx, ctx->tbl, zero_iv, bl) <= 0)
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2
            return 0;
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3.62k
        make_kn(ctx->k1, ctx->tbl, bl);
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3.62k
        make_kn(ctx->k2, ctx->k1, bl);
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3.62k
        OPENSSL_cleanse(ctx->tbl, bl);
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        /* Reset context again ready for first data block */
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3.62k
        if (!EVP_EncryptInit_ex2(ctx->cctx, NULL, NULL, zero_iv, param))
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0
            return 0;
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        /* Zero tbl so resume works */
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3.62k
        memset(ctx->tbl, 0, bl);
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3.62k
        ctx->nlast_block = 0;
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3.62k
    }
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4.76k
    return 1;
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5.92k
}
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int CMAC_Init(CMAC_CTX *ctx, const void *key, size_t keylen,
174
              const EVP_CIPHER *cipher, ENGINE *impl)
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7.33k
{
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7.33k
    return ossl_cmac_init(ctx, key, keylen, cipher, impl, NULL);
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7.33k
}
178
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int CMAC_Update(CMAC_CTX *ctx, const void *in, size_t dlen)
180
118k
{
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118k
    const unsigned char *data = in;
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118k
    int bl;
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118k
    size_t max_burst_blocks, cipher_blocks;
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118k
    unsigned char buf[LOCAL_BUF_SIZE];
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118k
    if (ctx->nlast_block == -1)
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1.14k
        return 0;
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117k
    if (dlen == 0)
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105k
        return 1;
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12.0k
    if ((bl = EVP_CIPHER_CTX_get_block_size(ctx->cctx)) == 0)
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0
        return 0;
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    /* Copy into partial block if we need to */
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12.0k
    if (ctx->nlast_block > 0) {
194
8.82k
        size_t nleft;
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196
8.82k
        nleft = bl - ctx->nlast_block;
197
8.82k
        if (dlen < nleft)
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2.45k
            nleft = dlen;
199
8.82k
        memcpy(ctx->last_block + ctx->nlast_block, data, nleft);
200
8.82k
        dlen -= nleft;
201
8.82k
        ctx->nlast_block += nleft;
202
        /* If no more to process return */
203
8.82k
        if (dlen == 0)
204
2.93k
            return 1;
205
5.89k
        data += nleft;
206
        /* Else not final block so encrypt it */
207
5.89k
        if (EVP_Cipher(ctx->cctx, ctx->tbl, ctx->last_block, bl) <= 0)
208
224
            return 0;
209
5.89k
    }
210
    /* Encrypt all but one of the complete blocks left */
211
212
8.87k
    max_burst_blocks = LOCAL_BUF_SIZE / bl;
213
8.87k
    cipher_blocks = (dlen - 1) / bl;
214
8.87k
    if (max_burst_blocks == 0) {
215
        /*
216
         * When block length is greater than local buffer size,
217
         * use ctx->tbl as cipher output.
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         */
219
0
        while (dlen > (size_t)bl) {
220
0
            if (EVP_Cipher(ctx->cctx, ctx->tbl, data, bl) <= 0)
221
0
                return 0;
222
0
            dlen -= bl;
223
0
            data += bl;
224
0
        }
225
8.87k
    } else {
226
8.96k
        while (cipher_blocks > max_burst_blocks) {
227
98
            if (EVP_Cipher(ctx->cctx, buf, data, max_burst_blocks * bl) <= 0)
228
0
                return 0;
229
98
            dlen -= max_burst_blocks * bl;
230
98
            data += max_burst_blocks * bl;
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98
            cipher_blocks -= max_burst_blocks;
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98
        }
233
8.87k
        if (cipher_blocks > 0) {
234
3.63k
            if (EVP_Cipher(ctx->cctx, buf, data, cipher_blocks * bl) <= 0)
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103
                return 0;
236
3.52k
            dlen -= cipher_blocks * bl;
237
3.52k
            data += cipher_blocks * bl;
238
3.52k
            memcpy(ctx->tbl, &buf[(cipher_blocks - 1) * bl], bl);
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3.52k
        }
240
8.87k
    }
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    /* Copy any data left to last block buffer */
242
8.76k
    memcpy(ctx->last_block, data, dlen);
243
8.76k
    ctx->nlast_block = dlen;
244
8.76k
    return 1;
245
246
8.87k
}
247
248
int CMAC_Final(CMAC_CTX *ctx, unsigned char *out, size_t *poutlen)
249
3.29k
{
250
3.29k
    int i, bl, lb;
251
252
3.29k
    if (ctx->nlast_block == -1)
253
0
        return 0;
254
3.29k
    if ((bl = EVP_CIPHER_CTX_get_block_size(ctx->cctx)) == 0)
255
0
        return 0;
256
3.29k
    if (poutlen != NULL)
257
3.29k
        *poutlen = (size_t)bl;
258
3.29k
    if (!out)
259
0
        return 1;
260
3.29k
    lb = ctx->nlast_block;
261
    /* Is last block complete? */
262
3.29k
    if (lb == bl) {
263
12.5k
        for (i = 0; i < bl; i++)
264
10.1k
            out[i] = ctx->last_block[i] ^ ctx->k1[i];
265
2.44k
    } else {
266
853
        ctx->last_block[lb] = 0x80;
267
853
        if (bl - lb > 1)
268
570
            memset(ctx->last_block + lb + 1, 0, bl - lb - 1);
269
10.2k
        for (i = 0; i < bl; i++)
270
9.35k
            out[i] = ctx->last_block[i] ^ ctx->k2[i];
271
853
    }
272
3.29k
    if (EVP_Cipher(ctx->cctx, out, out, bl) <= 0) {
273
2
        OPENSSL_cleanse(out, bl);
274
2
        return 0;
275
2
    }
276
3.29k
    return 1;
277
3.29k
}
278
279
int CMAC_resume(CMAC_CTX *ctx)
280
0
{
281
0
    if (ctx->nlast_block == -1)
282
0
        return 0;
283
    /*
284
     * The buffer "tbl" contains the last fully encrypted block which is the
285
     * last IV (or all zeroes if no last encrypted block). The last block has
286
     * not been modified since CMAC_final(). So reinitialising using the last
287
     * decrypted block will allow CMAC to continue after calling
288
     * CMAC_Final().
289
     */
290
0
    return EVP_EncryptInit_ex(ctx->cctx, NULL, NULL, NULL, ctx->tbl);
291
0
}