crypto/modes/ccm.c

	ccm.c revision 25cc6a4036ecb7db695004fd80f58ac8a82aedeb
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#ifndef _KERNEL
#include <strings.h>
#include <limits.h>
#include <assert.h>
#include <security/cryptoki.h>
#endif

#include <sys/types.h>
#include <sys/kmem.h>
#include <modes/modes.h>
#include <sys/crypto/common.h>
#include <sys/crypto/impl.h>

#if defined(__i386) || defined(__amd64)
#include <sys/byteorder.h>
#define UNALIGNED_POINTERS_PERMITTED
#endif

/*
 * Encrypt multiple blocks of data in CCM mode.  Decrypt for CCM mode
 * is done in another function.
 */
int
ccm_mode_encrypt_contiguous_blocks(ccm_ctx_t *ctx, char *data, size_t length,
    crypto_data_t *out, size_t block_size,
    int (*encrypt_block)(const void *, const uint8_t *, uint8_t *),
    void (*copy_block)(uint8_t *, uint8_t *),
    void (*xor_block)(uint8_t *, uint8_t *))
{
    size_t remainder = length;
    size_t need;
    uint8_t *datap = (uint8_t *)data;
    uint8_t *blockp;
    uint8_t *lastp;
    void *iov_or_mp;
    offset_t offset;
    uint8_t *out_data_1;
    uint8_t *out_data_2;
    size_t out_data_1_len;
    uint64_t counter;
    uint8_t *mac_buf;

    if (length + ctx->ccm_remainder_len < block_size) {
        /* accumulate bytes here and return */
        bcopy(datap,
            (uint8_t *)ctx->ccm_remainder + ctx->ccm_remainder_len,
            length);
        ctx->ccm_remainder_len += length;
        ctx->ccm_copy_to = datap;
        return (CRYPTO_SUCCESS);
    }

    lastp = (uint8_t *)ctx->ccm_cb;
    if (out != NULL)
        crypto_init_ptrs(out, &iov_or_mp, &offset);

    mac_buf = (uint8_t *)ctx->ccm_mac_buf;

    do {
        /* Unprocessed data from last call. */
        if (ctx->ccm_remainder_len > 0) {
            need = block_size - ctx->ccm_remainder_len;

            if (need > remainder)
                return (CRYPTO_DATA_LEN_RANGE);

            bcopy(datap, &((uint8_t *)ctx->ccm_remainder)
                [ctx->ccm_remainder_len], need);

            blockp = (uint8_t *)ctx->ccm_remainder;
        } else {
            blockp = datap;
        }

        /*
         * do CBC MAC
         *
         * XOR the previous cipher block current clear block.
         * mac_buf always contain previous cipher block.
         */
        xor_block(blockp, mac_buf);
        encrypt_block(ctx->ccm_keysched, mac_buf, mac_buf);

        /* ccm_cb is the counter block */
        encrypt_block(ctx->ccm_keysched, (uint8_t *)ctx->ccm_cb,
            (uint8_t *)ctx->ccm_tmp);

        lastp = (uint8_t *)ctx->ccm_tmp;

        /*
         * Increment counter. Counter bits are confined
         * to the bottom 64 bits of the counter block.
         */
#ifdef _LITTLE_ENDIAN
        counter = ntohll(ctx->ccm_cb[1] & ctx->ccm_counter_mask);
        counter = htonll(counter + 1);
#else
        counter = ctx->ccm_cb[1] & ctx->ccm_counter_mask;
        counter++;
#endif  /* _LITTLE_ENDIAN */
        counter &= ctx->ccm_counter_mask;
        ctx->ccm_cb[1] =
            (ctx->ccm_cb[1] & ~(ctx->ccm_counter_mask)) | counter;

        /*
         * XOR encrypted counter block with the current clear block.
         */
        xor_block(blockp, lastp);

        ctx->ccm_processed_data_len += block_size;

        if (out == NULL) {
            if (ctx->ccm_remainder_len > 0) {
                bcopy(blockp, ctx->ccm_copy_to,
                    ctx->ccm_remainder_len);
                bcopy(blockp + ctx->ccm_remainder_len, datap,
                    need);
            }
        } else {
            crypto_get_ptrs(out, &iov_or_mp, &offset, &out_data_1,
                &out_data_1_len, &out_data_2, block_size);

            /* copy block to where it belongs */
            if (out_data_1_len == block_size) {
                copy_block(lastp, out_data_1);
            } else {
                bcopy(lastp, out_data_1, out_data_1_len);
                if (out_data_2 != NULL) {
                    bcopy(lastp + out_data_1_len,
                        out_data_2,
                        block_size - out_data_1_len);
                }
            }
            /* update offset */
            out->cd_offset += block_size;
        }

        /* Update pointer to next block of data to be processed. */
        if (ctx->ccm_remainder_len != 0) {
            datap += need;
            ctx->ccm_remainder_len = 0;
        } else {
            datap += block_size;
        }

        remainder = (size_t)&data[length] - (size_t)datap;

        /* Incomplete last block. */
        if (remainder > 0 && remainder < block_size) {
            bcopy(datap, ctx->ccm_remainder, remainder);
            ctx->ccm_remainder_len = remainder;
            ctx->ccm_copy_to = datap;
            goto out;
        }
        ctx->ccm_copy_to = NULL;

    } while (remainder > 0);

out:
    return (CRYPTO_SUCCESS);
}

void
calculate_ccm_mac(ccm_ctx_t *ctx, uint8_t *ccm_mac,
    int (*encrypt_block)(const void *, const uint8_t *, uint8_t *))
{
    uint64_t counter;
    uint8_t *counterp, *mac_buf;
    int i;

    mac_buf = (uint8_t *)ctx->ccm_mac_buf;

    /* first counter block start with index 0 */
    counter = 0;
    ctx->ccm_cb[1] = (ctx->ccm_cb[1] & ~(ctx->ccm_counter_mask)) | counter;

    counterp = (uint8_t *)ctx->ccm_tmp;
    encrypt_block(ctx->ccm_keysched, (uint8_t *)ctx->ccm_cb, counterp);

    /* calculate XOR of MAC with first counter block */
    for (i = 0; i < ctx->ccm_mac_len; i++) {
        ccm_mac[i] = mac_buf[i] ^ counterp[i];
    }
}

/* ARGSUSED */
int
ccm_encrypt_final(ccm_ctx_t *ctx, crypto_data_t *out, size_t block_size,
    int (*encrypt_block)(const void *, const uint8_t *, uint8_t *),
    void (*xor_block)(uint8_t *, uint8_t *))
{
    uint8_t *lastp, *mac_buf, *ccm_mac_p, *macp;
    void *iov_or_mp;
    offset_t offset;
    uint8_t *out_data_1;
    uint8_t *out_data_2;
    size_t out_data_1_len;
    int i;

    if (out->cd_length < (ctx->ccm_remainder_len + ctx->ccm_mac_len)) {
        return (CRYPTO_DATA_LEN_RANGE);
    }

    /*
     * When we get here, the number of bytes of payload processed
     * plus whatever data remains, if any,
     * should be the same as the number of bytes that's being
     * passed in the argument during init time.
     */
    if ((ctx->ccm_processed_data_len + ctx->ccm_remainder_len)
        != (ctx->ccm_data_len)) {
        return (CRYPTO_DATA_LEN_RANGE);
    }

    mac_buf = (uint8_t *)ctx->ccm_mac_buf;

    if (ctx->ccm_remainder_len > 0) {

        /* ccm_mac_input_buf is not used for encryption */
        macp = (uint8_t *)ctx->ccm_mac_input_buf;
        bzero(macp, block_size);

        /* copy remainder to temporary buffer */
        bcopy(ctx->ccm_remainder, macp, ctx->ccm_remainder_len);

        /* calculate the CBC MAC */
        xor_block(macp, mac_buf);
        encrypt_block(ctx->ccm_keysched, mac_buf, mac_buf);

        /* calculate the counter mode */
        lastp = (uint8_t *)ctx->ccm_tmp;
        encrypt_block(ctx->ccm_keysched, (uint8_t *)ctx->ccm_cb, lastp);

        /* XOR with counter block */
        for (i = 0; i < ctx->ccm_remainder_len; i++) {
            macp[i] ^= lastp[i];
        }
        ctx->ccm_processed_data_len += ctx->ccm_remainder_len;
    }

    /* Calculate the CCM MAC */
    ccm_mac_p = (uint8_t *)ctx->ccm_tmp;
    calculate_ccm_mac(ctx, ccm_mac_p, encrypt_block);

    crypto_init_ptrs(out, &iov_or_mp, &offset);
    crypto_get_ptrs(out, &iov_or_mp, &offset, &out_data_1,
        &out_data_1_len, &out_data_2,
        ctx->ccm_remainder_len + ctx->ccm_mac_len);

    if (ctx->ccm_remainder_len > 0) {

        /* copy temporary block to where it belongs */
        if (out_data_2 == NULL) {
            /* everything will fit in out_data_1 */
            bcopy(macp, out_data_1, ctx->ccm_remainder_len);
            bcopy(ccm_mac_p, out_data_1 + ctx->ccm_remainder_len,
                ctx->ccm_mac_len);
        } else {

            if (out_data_1_len < ctx->ccm_remainder_len) {

                size_t data_2_len_used;

                bcopy(macp, out_data_1, out_data_1_len);

                data_2_len_used = ctx->ccm_remainder_len
                    - out_data_1_len;

                bcopy((uint8_t *)macp + out_data_1_len,
                    out_data_2, data_2_len_used);
                bcopy(ccm_mac_p, out_data_2 + data_2_len_used,
                    ctx->ccm_mac_len);
            } else {
                bcopy(macp, out_data_1, out_data_1_len);
                if (out_data_1_len == ctx->ccm_remainder_len) {
                    /* mac will be in out_data_2 */
                    bcopy(ccm_mac_p, out_data_2,
                        ctx->ccm_mac_len);
                } else {
                    size_t len_not_used = out_data_1_len -
                        ctx->ccm_remainder_len;
                    /*
                     * part of mac in will be in
                     * out_data_1, part of the mac will be
                     * in out_data_2
                     */
                    bcopy(ccm_mac_p,
                        out_data_1 + ctx->ccm_remainder_len,
                        len_not_used);
                    bcopy(ccm_mac_p + len_not_used,
                        out_data_2,
                        ctx->ccm_mac_len - len_not_used);

                }
            }
        }
    } else {
        /* copy block to where it belongs */
        bcopy(ccm_mac_p, out_data_1, out_data_1_len);
        if (out_data_2 != NULL) {
            bcopy(ccm_mac_p + out_data_1_len, out_data_2,
                block_size - out_data_1_len);
        }
    }
    out->cd_offset += ctx->ccm_remainder_len + ctx->ccm_mac_len;
    ctx->ccm_remainder_len = 0;
    return (CRYPTO_SUCCESS);
}

/*
 * This will only deal with decrypting the last block of the input that
 * might not be a multiple of block length.
 */
void
ccm_decrypt_incomplete_block(ccm_ctx_t *ctx,
    int (*encrypt_block)(const void *, const uint8_t *, uint8_t *))
{
    uint8_t *datap, *outp, *counterp;
    int i;

    datap = (uint8_t *)ctx->ccm_remainder;
    outp = &((ctx->ccm_pt_buf)[ctx->ccm_processed_data_len]);

    counterp = (uint8_t *)ctx->ccm_tmp;
    encrypt_block(ctx->ccm_keysched, (uint8_t *)ctx->ccm_cb, counterp);

    /* XOR with counter block */
    for (i = 0; i < ctx->ccm_remainder_len; i++) {
        outp[i] = datap[i] ^ counterp[i];
    }
}

/*
 * This will decrypt the cipher text.  However, the plaintext won't be
 * returned to the caller.  It will be returned when decrypt_final() is
 * called if the MAC matches
 */
/* ARGSUSED */
int
ccm_mode_decrypt_contiguous_blocks(ccm_ctx_t *ctx, char *data, size_t length,
    crypto_data_t *out, size_t block_size,
    int (*encrypt_block)(const void *, const uint8_t *, uint8_t *),
    void (*copy_block)(uint8_t *, uint8_t *),
    void (*xor_block)(uint8_t *, uint8_t *))
{
    size_t remainder = length;
    size_t need;
    uint8_t *datap = (uint8_t *)data;
    uint8_t *blockp;
    uint8_t *cbp;
    uint64_t counter;
    size_t pt_len, total_decrypted_len, mac_len, pm_len, pd_len;
    uint8_t *resultp;


    pm_len = ctx->ccm_processed_mac_len;

    if (pm_len > 0) {
        uint8_t *tmp;
        /*
         * all ciphertext has been processed, just waiting for
         * part of the value of the mac
         */
        if ((pm_len + length) > ctx->ccm_mac_len) {
            return (CRYPTO_ENCRYPTED_DATA_LEN_RANGE);
        }
        tmp = (uint8_t *)ctx->ccm_mac_input_buf;

        bcopy(datap, tmp + pm_len, length);

        ctx->ccm_processed_mac_len += length;
        return (CRYPTO_SUCCESS);
    }

    /*
     * If we decrypt the given data, what total amount of data would
     * have been decrypted?
     */
    pd_len = ctx->ccm_processed_data_len;
    total_decrypted_len = pd_len + length + ctx->ccm_remainder_len;

    if (total_decrypted_len >
        (ctx->ccm_data_len + ctx->ccm_mac_len)) {
        return (CRYPTO_ENCRYPTED_DATA_LEN_RANGE);
    }

    pt_len = ctx->ccm_data_len;

    if (total_decrypted_len > pt_len) {
        /*
         * part of the input will be the MAC, need to isolate that
         * to be dealt with later.  The left-over data in
         * ccm_remainder_len from last time will not be part of the
         * MAC.  Otherwise, it would have already been taken out
         * when this call is made last time.
         */
        size_t pt_part = pt_len - pd_len - ctx->ccm_remainder_len;

        mac_len = length - pt_part;

        ctx->ccm_processed_mac_len = mac_len;
        bcopy(data + pt_part, ctx->ccm_mac_input_buf, mac_len);

        if (pt_part + ctx->ccm_remainder_len < block_size) {
            /*
             * since this is last of the ciphertext, will
             * just decrypt with it here
             */
            bcopy(datap, &((uint8_t *)ctx->ccm_remainder)
                [ctx->ccm_remainder_len], pt_part);
            ctx->ccm_remainder_len += pt_part;
            ccm_decrypt_incomplete_block(ctx, encrypt_block);
            ctx->ccm_remainder_len = 0;
            ctx->ccm_processed_data_len += pt_part;
            return (CRYPTO_SUCCESS);
        } else {
            /* let rest of the code handle this */
            length = pt_part;
        }
    } else if (length + ctx->ccm_remainder_len < block_size) {
            /* accumulate bytes here and return */
        bcopy(datap,
            (uint8_t *)ctx->ccm_remainder + ctx->ccm_remainder_len,
            length);
        ctx->ccm_remainder_len += length;
        ctx->ccm_copy_to = datap;
        return (CRYPTO_SUCCESS);
    }

    do {
        /* Unprocessed data from last call. */
        if (ctx->ccm_remainder_len > 0) {
            need = block_size - ctx->ccm_remainder_len;

            if (need > remainder)
                return (CRYPTO_ENCRYPTED_DATA_LEN_RANGE);

            bcopy(datap, &((uint8_t *)ctx->ccm_remainder)
                [ctx->ccm_remainder_len], need);

            blockp = (uint8_t *)ctx->ccm_remainder;
        } else {
            blockp = datap;
        }

        /* Calculate the counter mode, ccm_cb is the counter block */
        cbp = (uint8_t *)ctx->ccm_tmp;
        encrypt_block(ctx->ccm_keysched, (uint8_t *)ctx->ccm_cb, cbp);

        /*
         * Increment counter.
         * Counter bits are confined to the bottom 64 bits
         */
#ifdef _LITTLE_ENDIAN
        counter = ntohll(ctx->ccm_cb[1] & ctx->ccm_counter_mask);
        counter = htonll(counter + 1);
#else
        counter = ctx->ccm_cb[1] & ctx->ccm_counter_mask;
        counter++;
#endif  /* _LITTLE_ENDIAN */
        counter &= ctx->ccm_counter_mask;
        ctx->ccm_cb[1] =
            (ctx->ccm_cb[1] & ~(ctx->ccm_counter_mask)) | counter;

        /* XOR with the ciphertext */
        xor_block(blockp, cbp);

        /* Copy the plaintext to the "holding buffer" */
        resultp = (uint8_t *)ctx->ccm_pt_buf +
            ctx->ccm_processed_data_len;
        copy_block(cbp, resultp);

        ctx->ccm_processed_data_len += block_size;

        ctx->ccm_lastp = blockp;

        /* Update pointer to next block of data to be processed. */
        if (ctx->ccm_remainder_len != 0) {
            datap += need;
            ctx->ccm_remainder_len = 0;
        } else {
            datap += block_size;
        }

        remainder = (size_t)&data[length] - (size_t)datap;

        /* Incomplete last block */
        if (remainder > 0 && remainder < block_size) {
            bcopy(datap, ctx->ccm_remainder, remainder);
            ctx->ccm_remainder_len = remainder;
            ctx->ccm_copy_to = datap;
            if (ctx->ccm_processed_mac_len > 0) {
                /*
                 * not expecting anymore ciphertext, just
                 * compute plaintext for the remaining input
                 */
                ccm_decrypt_incomplete_block(ctx,
                    encrypt_block);
                ctx->ccm_processed_data_len += remainder;
                ctx->ccm_remainder_len = 0;
            }
            goto out;
        }
        ctx->ccm_copy_to = NULL;

    } while (remainder > 0);

out:
    return (CRYPTO_SUCCESS);
}

int
ccm_decrypt_final(ccm_ctx_t *ctx, crypto_data_t *out, size_t block_size,
    int (*encrypt_block)(const void *, const uint8_t *, uint8_t *),
    void (*copy_block)(uint8_t *, uint8_t *),
    void (*xor_block)(uint8_t *, uint8_t *))
{
    size_t mac_remain, pt_len;
    uint8_t *pt, *mac_buf, *macp, *ccm_mac_p;
    void *iov_or_mp;
    offset_t offset;
    uint8_t *out_data_1, *out_data_2;
    size_t out_data_1_len;

    pt_len = ctx->ccm_data_len;

    /* Make sure output buffer can fit all of the plaintext */
    if (out->cd_length < pt_len) {
        return (CRYPTO_DATA_LEN_RANGE);
    }

    pt = ctx->ccm_pt_buf;
    mac_remain = ctx->ccm_processed_data_len;
    mac_buf = (uint8_t *)ctx->ccm_mac_buf;

    macp = (uint8_t *)ctx->ccm_tmp;

    while (mac_remain > 0) {

        if (mac_remain < block_size) {
            bzero(macp, block_size);
            bcopy(pt, macp, mac_remain);
            mac_remain = 0;
        } else {
            copy_block(pt, macp);
            mac_remain -= block_size;
            pt += block_size;
        }

        /* calculate the CBC MAC */
        xor_block(macp, mac_buf);
        encrypt_block(ctx->ccm_keysched, mac_buf, mac_buf);
    }

    /* Calculate the CCM MAC */
    ccm_mac_p = (uint8_t *)ctx->ccm_tmp;
    calculate_ccm_mac((ccm_ctx_t *)ctx, ccm_mac_p, encrypt_block);

    /* compare the input CCM MAC value with what we calculated */
    if (bcmp(ctx->ccm_mac_input_buf, ccm_mac_p, ctx->ccm_mac_len)) {
        /* They don't match */
        return (CRYPTO_INVALID_MAC);
    } else {
        crypto_init_ptrs(out, &iov_or_mp, &offset);
        crypto_get_ptrs(out, &iov_or_mp, &offset, &out_data_1,
            &out_data_1_len, &out_data_2, pt_len);
        bcopy(ctx->ccm_pt_buf, out_data_1, out_data_1_len);
        if (out_data_2 != NULL) {
            bcopy((ctx->ccm_pt_buf) + out_data_1_len,
                out_data_2, pt_len - out_data_1_len);
        }
        out->cd_offset += pt_len;
    }
    return (CRYPTO_SUCCESS);
}

int
ccm_validate_args(CK_AES_CCM_PARAMS *ccm_param, boolean_t is_encrypt_init)
{
    size_t macSize, nonceSize;
    uint8_t q;
    uint64_t maxValue;

    /*
     * Check the length of the MAC.  The only valid
     * lengths for the MAC are: 4, 6, 8, 10, 12, 14, 16
     */
    macSize = ccm_param->ulMACSize;
    if ((macSize < 4) || (macSize > 16) || ((macSize % 2) != 0)) {
        return (CRYPTO_MECHANISM_PARAM_INVALID);
    }

    /* Check the nonce length.  Valid values are 7, 8, 9, 10, 11, 12, 13 */
    nonceSize = ccm_param->ulNonceSize;
    if ((nonceSize < 7) || (nonceSize > 13)) {
        return (CRYPTO_MECHANISM_PARAM_INVALID);
    }

    /* q is the length of the field storing the length, in bytes */
    q = (uint8_t)((15 - nonceSize) & 0xFF);


    /*
     * If it is decrypt, need to make sure size of ciphertext is at least
     * bigger than MAC len
     */
    if ((!is_encrypt_init) && (ccm_param->ulDataSize < macSize)) {
        return (CRYPTO_MECHANISM_PARAM_INVALID);
    }

    /*
     * Check to make sure the length of the payload is within the
     * range of values allowed by q
     */
    if (q < 8) {
        maxValue = (1ULL << (q * 8)) - 1;
    } else {
        maxValue = ULONG_MAX;
    }

    if (ccm_param->ulDataSize > maxValue) {
        return (CRYPTO_MECHANISM_PARAM_INVALID);
    }
    return (CRYPTO_SUCCESS);
}

/*
 * Format the first block used in CBC-MAC (B0) and the initial counter
 * block based on formatting functions and counter generation functions
 * specified in RFC 3610 and NIST publication 800-38C, appendix A
 *
 * b0 is the first block used in CBC-MAC
 * cb0 is the first counter block
 *
 * It's assumed that the arguments b0 and cb0 are preallocated AES blocks
 *
 */
static void
ccm_format_initial_blocks(uchar_t *nonce, ulong_t nonceSize,
    ulong_t authDataSize, uint8_t *b0, ccm_ctx_t *aes_ctx)
{
    uint64_t payloadSize;
    uint8_t t, q, have_adata = 0;
    size_t limit;
    int i, j, k;
    uint64_t mask = 0;
    uint8_t *cb;

    q = (uint8_t)((15 - nonceSize) & 0xFF);
    t = (uint8_t)((aes_ctx->ccm_mac_len) & 0xFF);

    /* Construct the first octet of b0 */
    if (authDataSize > 0) {
        have_adata = 1;
    }
    b0[0] = (have_adata << 6) | (((t - 2)  / 2) << 3) | (q - 1);

    /* copy the nonce value into b0 */
    bcopy(nonce, &(b0[1]), nonceSize);

    /* store the length of the payload into b0 */
    bzero(&(b0[1+nonceSize]), q);

    payloadSize = aes_ctx->ccm_data_len;
    limit = 8 < q ? 8 : q;

    for (i = 0, j = 0, k = 15; i < limit; i++, j += 8, k--) {
        b0[k] = (uint8_t)((payloadSize >> j) & 0xFF);
    }

    /* format the counter block */

    cb = (uint8_t *)aes_ctx->ccm_cb;

    cb[0] = 0x07 & (q-1); /* first byte */

    /* copy the nonce value into the counter block */
    bcopy(nonce, &(cb[1]), nonceSize);

    bzero(&(cb[1+nonceSize]), q);

    /* Create the mask for the counter field based on the size of nonce */
    q <<= 3;
    while (q-- > 0) {
        mask |= (1ULL << q);
    }

#ifdef _LITTLE_ENDIAN
    mask = htonll(mask);
#endif
    aes_ctx->ccm_counter_mask = mask;

    /*
     * During calculation, we start using counter block 1, we will
     * set it up right here.
     * We can just set the last byte to have the value 1, because
     * even with the biggest nonce of 13, the last byte of the
     * counter block will be used for the counter value.
     */
    cb[15] = 0x01;
}

/*
 * Encode the length of the associated data as
 * specified in RFC 3610 and NIST publication 800-38C, appendix A
 */
static void
encode_adata_len(ulong_t auth_data_len, uint8_t *encoded, size_t *encoded_len)
{
#ifdef UNALIGNED_POINTERS_PERMITTED
    uint32_t    *lencoded_ptr;
#ifdef _LP64
    uint64_t    *llencoded_ptr;
#endif
#endif  /* UNALIGNED_POINTERS_PERMITTED */

    if (auth_data_len < ((1ULL<<16) - (1ULL<<8))) {
        /* 0 < a < (2^16-2^8) */
        *encoded_len = 2;
        encoded[0] = (auth_data_len & 0xff00) >> 8;
        encoded[1] = auth_data_len & 0xff;

    } else if ((auth_data_len >= ((1ULL<<16) - (1ULL<<8))) &&
        (auth_data_len < (1ULL << 31))) {
        /* (2^16-2^8) <= a < 2^32 */
        *encoded_len = 6;
        encoded[0] = 0xff;
        encoded[1] = 0xfe;
#ifdef UNALIGNED_POINTERS_PERMITTED
        lencoded_ptr = (uint32_t *)&encoded[2];
        *lencoded_ptr = htonl(auth_data_len);
#else
        encoded[2] = (auth_data_len & 0xff000000) >> 24;
        encoded[3] = (auth_data_len & 0xff0000) >> 16;
        encoded[4] = (auth_data_len & 0xff00) >> 8;
        encoded[5] = auth_data_len & 0xff;
#endif  /* UNALIGNED_POINTERS_PERMITTED */

#ifdef _LP64
    } else {
        /* 2^32 <= a < 2^64 */
        *encoded_len = 10;
        encoded[0] = 0xff;
        encoded[1] = 0xff;
#ifdef UNALIGNED_POINTERS_PERMITTED
        llencoded_ptr = (uint64_t *)&encoded[2];
        *llencoded_ptr = htonl(auth_data_len);
#else
        encoded[2] = (auth_data_len & 0xff00000000000000) >> 56;
        encoded[3] = (auth_data_len & 0xff000000000000) >> 48;
        encoded[4] = (auth_data_len & 0xff0000000000) >> 40;
        encoded[5] = (auth_data_len & 0xff00000000) >> 32;
        encoded[6] = (auth_data_len & 0xff000000) >> 24;
        encoded[7] = (auth_data_len & 0xff0000) >> 16;
        encoded[8] = (auth_data_len & 0xff00) >> 8;
        encoded[9] = auth_data_len & 0xff;
#endif  /* UNALIGNED_POINTERS_PERMITTED */
#endif  /* _LP64 */
    }
}

/*
 * The following function should be call at encrypt or decrypt init time
 * for AES CCM mode.
 */
int
ccm_init(ccm_ctx_t *ctx, unsigned char *nonce, size_t nonce_len,
    unsigned char *auth_data, size_t auth_data_len, size_t block_size,
    int (*encrypt_block)(const void *, const uint8_t *, uint8_t *),
    void (*xor_block)(uint8_t *, uint8_t *))
{
    uint8_t *mac_buf, *datap, *ivp, *authp;
    size_t remainder, processed;
    uint8_t encoded_a[10]; /* max encoded auth data length is 10 octets */
    size_t encoded_a_len = 0;

    mac_buf = (uint8_t *)&(ctx->ccm_mac_buf);

    /*
     * Format the 1st block for CBC-MAC and construct the
     * 1st counter block.
     *
     * aes_ctx->ccm_iv is used for storing the counter block
     * mac_buf will store b0 at this time.
     */
    ccm_format_initial_blocks(nonce, nonce_len,
        auth_data_len, mac_buf, ctx);

    /* The IV for CBC MAC for AES CCM mode is always zero */
    ivp = (uint8_t *)ctx->ccm_tmp;
    bzero(ivp, block_size);

    xor_block(ivp, mac_buf);

    /* encrypt the nonce */
    encrypt_block(ctx->ccm_keysched, mac_buf, mac_buf);

    /* take care of the associated data, if any */
    if (auth_data_len == 0) {
        return (CRYPTO_SUCCESS);
    }

    encode_adata_len(auth_data_len, encoded_a, &encoded_a_len);

    remainder = auth_data_len;

    /* 1st block: it contains encoded associated data, and some data */
    authp = (uint8_t *)ctx->ccm_tmp;
    bzero(authp, block_size);
    bcopy(encoded_a, authp, encoded_a_len);
    processed = block_size - encoded_a_len;
    if (processed > auth_data_len) {
        /* in case auth_data is very small */
        processed = auth_data_len;
    }
    bcopy(auth_data, authp+encoded_a_len, processed);
    /* xor with previous buffer */
    xor_block(authp, mac_buf);
    encrypt_block(ctx->ccm_keysched, mac_buf, mac_buf);
    remainder -= processed;
    if (remainder == 0) {
        /* a small amount of associated data, it's all done now */
        return (CRYPTO_SUCCESS);
    }

    do {
        if (remainder < block_size) {
            /*
             * There's not a block full of data, pad rest of
             * buffer with zero
             */
            bzero(authp, block_size);
            bcopy(&(auth_data[processed]), authp, remainder);
            datap = (uint8_t *)authp;
            remainder = 0;
        } else {
            datap = (uint8_t *)(&(auth_data[processed]));
            processed += block_size;
            remainder -= block_size;
        }

        xor_block(datap, mac_buf);
        encrypt_block(ctx->ccm_keysched, mac_buf, mac_buf);

    } while (remainder > 0);

    return (CRYPTO_SUCCESS);
}

int
ccm_init_ctx(ccm_ctx_t *ccm_ctx, char *param, int kmflag,
    boolean_t is_encrypt_init, size_t block_size,
    int (*encrypt_block)(const void *, const uint8_t *, uint8_t *),
    void (*xor_block)(uint8_t *, uint8_t *))
{
    int rv;
    CK_AES_CCM_PARAMS *ccm_param;

    if (param != NULL) {
        ccm_param = (CK_AES_CCM_PARAMS *)param;

        if ((rv = ccm_validate_args(ccm_param,
            is_encrypt_init)) != 0) {
            return (rv);
        }

        ccm_ctx->ccm_mac_len = ccm_param->ulMACSize;
        if (is_encrypt_init) {
            ccm_ctx->ccm_data_len = ccm_param->ulDataSize;
        } else {
            ccm_ctx->ccm_data_len =
                ccm_param->ulDataSize - ccm_ctx->ccm_mac_len;
            ccm_ctx->ccm_processed_mac_len = 0;
        }
        ccm_ctx->ccm_processed_data_len = 0;

        ccm_ctx->ccm_flags |= CCM_MODE;
    } else {
        rv = CRYPTO_MECHANISM_PARAM_INVALID;
        goto out;
    }

    if (ccm_init(ccm_ctx, ccm_param->nonce, ccm_param->ulNonceSize,
        ccm_param->authData, ccm_param->ulAuthDataSize, block_size,
        encrypt_block, xor_block) != 0) {
        rv = CRYPTO_MECHANISM_PARAM_INVALID;
        goto out;
    }
    if (!is_encrypt_init) {
        /* allocate buffer for storing decrypted plaintext */
#ifdef _KERNEL
        ccm_ctx->ccm_pt_buf = kmem_alloc(ccm_ctx->ccm_data_len,
            kmflag);
#else
        ccm_ctx->ccm_pt_buf = malloc(ccm_ctx->ccm_data_len);
#endif
        if (ccm_ctx->ccm_pt_buf == NULL) {
            rv = CRYPTO_HOST_MEMORY;
        }
    }
out:
    return (rv);
}

void *
ccm_alloc_ctx(int kmflag)
{
    ccm_ctx_t *ccm_ctx;

#ifdef _KERNEL
    if ((ccm_ctx = kmem_zalloc(sizeof (ccm_ctx_t), kmflag)) == NULL)
#else
    if ((ccm_ctx = calloc(1, sizeof (ccm_ctx_t))) == NULL)
#endif
        return (NULL);

    ccm_ctx->ccm_flags = CCM_MODE;
    return (ccm_ctx);
}