/*
 * 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 2010 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * RC4 provider for the Kernel Cryptographic Framework (KCF)
 */

#include <sys/types.h>
#include <sys/systm.h>
#include <sys/modctl.h>
#include <sys/cmn_err.h>
#include <sys/ddi.h>
#include <sys/crypto/common.h>
#include <sys/crypto/spi.h>
#include <sys/sysmacros.h>
#include <sys/strsun.h>
#include <arcfour.h>

extern struct mod_ops mod_cryptoops;

/*
 * Module linkage information for the kernel.
 */
static struct modlcrypto modlcrypto = {
        &mod_cryptoops,
        "RC4 Kernel SW Provider"
};

static struct modlinkage modlinkage = {
        MODREV_1,
        (void *)&modlcrypto,
        NULL
};

/*
 * CSPI information (entry points, provider info, etc.)
 */

#define RC4_MECH_INFO_TYPE      0
/*
 * Mechanism info structure passed to KCF during registration.
 */
static crypto_mech_info_t rc4_mech_info_tab[] = {
        {SUN_CKM_RC4, RC4_MECH_INFO_TYPE,
            CRYPTO_FG_ENCRYPT | CRYPTO_FG_ENCRYPT_ATOMIC |
            CRYPTO_FG_DECRYPT | CRYPTO_FG_DECRYPT_ATOMIC,
            ARCFOUR_MIN_KEY_BITS, ARCFOUR_MAX_KEY_BITS,
            CRYPTO_KEYSIZE_UNIT_IN_BITS | CRYPTO_CAN_SHARE_OPSTATE}
};

static void rc4_provider_status(crypto_provider_handle_t, uint_t *);

static crypto_control_ops_t rc4_control_ops = {
        rc4_provider_status
};

static int rc4_common_init(crypto_ctx_t *, crypto_mechanism_t *,
    crypto_key_t *, crypto_spi_ctx_template_t, crypto_req_handle_t);

static int rc4_crypt_update(crypto_ctx_t *, crypto_data_t *, crypto_data_t *,
    crypto_req_handle_t);

static int rc4_crypt_final(crypto_ctx_t *, crypto_data_t *,
    crypto_req_handle_t);

static int rc4_crypt(crypto_ctx_t *, crypto_data_t *, crypto_data_t *,
    crypto_req_handle_t);

static int rc4_crypt_atomic(crypto_provider_handle_t, crypto_session_id_t,
    crypto_mechanism_t *, crypto_key_t *, crypto_data_t *,
    crypto_data_t *, crypto_spi_ctx_template_t, crypto_req_handle_t);


static crypto_cipher_ops_t rc4_cipher_ops = {
        rc4_common_init,
        rc4_crypt,
        rc4_crypt_update,
        rc4_crypt_final,
        rc4_crypt_atomic,
        rc4_common_init,
        rc4_crypt,
        rc4_crypt_update,
        rc4_crypt_final,
        rc4_crypt_atomic
};

static int rc4_free_context(crypto_ctx_t *);

static crypto_ctx_ops_t rc4_ctx_ops = {
        NULL,
        rc4_free_context
};

static crypto_ops_t rc4_crypto_ops = {
        &rc4_control_ops,
        NULL,
        &rc4_cipher_ops,
        NULL,
        NULL,
        NULL,
        NULL,
        NULL,
        NULL,
        NULL,
        NULL,
        NULL,
        NULL,
        &rc4_ctx_ops
};

static crypto_provider_info_t rc4_prov_info = {
        CRYPTO_SPI_VERSION_1,
        "RC4 Software Provider",
        CRYPTO_SW_PROVIDER,
        {&modlinkage},
        NULL,
        &rc4_crypto_ops,
        sizeof (rc4_mech_info_tab)/sizeof (crypto_mech_info_t),
        rc4_mech_info_tab
};

static crypto_kcf_provider_handle_t rc4_prov_handle = 0;

static mblk_t *advance_position(mblk_t *, off_t, uchar_t **);
static int crypto_arcfour_crypt(ARCFour_key *, uchar_t *, crypto_data_t *,
    int);

int
_init(void)
{
        int ret;

        if ((ret = mod_install(&modlinkage)) != 0)
                return (ret);

        /* Register with KCF.  If the registration fails, remove the module. */
        if (crypto_register_provider(&rc4_prov_info, &rc4_prov_handle)) {
                (void) mod_remove(&modlinkage);
                return (EACCES);
        }

        return (0);
}

int
_fini(void)
{
        /* Unregister from KCF if module is registered */
        if (rc4_prov_handle != 0) {
                if (crypto_unregister_provider(rc4_prov_handle))
                        return (EBUSY);

                rc4_prov_handle = 0;
        }

        return (mod_remove(&modlinkage));
}

int
_info(struct modinfo *modinfop)
{
        return (mod_info(&modlinkage, modinfop));
}


/*
 * KCF software provider control entry points.
 */
/* ARGSUSED */
static void
rc4_provider_status(crypto_provider_handle_t provider, uint_t *status)
{
        *status = CRYPTO_PROVIDER_READY;
}

/* ARGSUSED */
static int
rc4_common_init(crypto_ctx_t *ctx, crypto_mechanism_t *mechanism,
    crypto_key_t *key, crypto_spi_ctx_template_t template,
    crypto_req_handle_t req)
{
        ARCFour_key *keystream;

        if ((mechanism)->cm_type != RC4_MECH_INFO_TYPE)
                return (CRYPTO_MECHANISM_INVALID);

        if (key->ck_format != CRYPTO_KEY_RAW)
                return (CRYPTO_KEY_TYPE_INCONSISTENT);

        if (key->ck_length < ARCFOUR_MIN_KEY_BITS ||
            key->ck_length > ARCFOUR_MAX_KEY_BITS) {
                return (CRYPTO_KEY_SIZE_RANGE);
        }

        /*
         * Allocate an RC4 key stream.
         */
        if ((keystream = kmem_alloc(sizeof (ARCFour_key),
            crypto_kmflag(req))) == NULL)
                return (CRYPTO_HOST_MEMORY);

        arcfour_key_init(keystream, key->ck_data,
            CRYPTO_BITS2BYTES(key->ck_length));

        ctx->cc_provider_private = keystream;

        return (CRYPTO_SUCCESS);
}

static int
rc4_crypt(crypto_ctx_t *ctx, crypto_data_t *input, crypto_data_t *output,
    crypto_req_handle_t req)
{
        int ret;

        ret = rc4_crypt_update(ctx, input, output, req);

        if (ret != CRYPTO_BUFFER_TOO_SMALL)
                (void) rc4_free_context(ctx);

        return (ret);
}

/* ARGSUSED */
static int
rc4_crypt_update(crypto_ctx_t *ctx, crypto_data_t *input, crypto_data_t *output,
    crypto_req_handle_t req)
{
        int ret = CRYPTO_SUCCESS;

        ARCFour_key *key;
        off_t saveoffset;

        ASSERT(ctx->cc_provider_private != NULL);

        if ((ctx->cc_flags & CRYPTO_USE_OPSTATE) && ctx->cc_opstate != NULL)
                key = ctx->cc_opstate;
        else
                key = ctx->cc_provider_private;

        /* Simple case: in-line encipherment */

        if (output == NULL) {
                switch (input->cd_format) {
                case CRYPTO_DATA_RAW: {
                        char *start, *end;
                        start = input->cd_raw.iov_base + input->cd_offset;

                        end =  input->cd_raw.iov_base + input->cd_raw.iov_len;

                        if (start + input->cd_length > end)
                                return (CRYPTO_DATA_INVALID);

                        arcfour_crypt(key, (uchar_t *)start, (uchar_t *)start,
                            input->cd_length);
                        break;
                }
                case CRYPTO_DATA_MBLK: {
                        uchar_t *start, *end;
                        size_t len, left;
                        mblk_t *mp = input->cd_mp, *mp1, *mp2;

                        ASSERT(mp != NULL);

                        mp1 = advance_position(mp, input->cd_offset, &start);

                        if (mp1 == NULL)
                                return (CRYPTO_DATA_LEN_RANGE);

                        mp2 = advance_position(mp, input->cd_offset +
                            input->cd_length, &end);

                        if (mp2 == NULL)
                                return (CRYPTO_DATA_LEN_RANGE);

                        left = input->cd_length;
                        while (mp1 != NULL) {
                                if (_PTRDIFF(mp1->b_wptr, start) > left) {
                                        len = left;
                                        arcfour_crypt(key, start, start, len);
                                        mp1 = NULL;
                                } else {
                                        len = _PTRDIFF(mp1->b_wptr, start);
                                        arcfour_crypt(key, start, start, len);
                                        mp1 = mp1->b_cont;
                                        start = mp1->b_rptr;
                                        left -= len;
                                }
                        }
                        break;
                }
                case CRYPTO_DATA_UIO: {
                        uio_t *uiop = input->cd_uio;
                        off_t offset = input->cd_offset;
                        size_t length = input->cd_length;
                        uint_t vec_idx;
                        size_t cur_len;

                        /*
                         * Jump to the first iovec containing data to be
                         * processed.
                         */
                        for (vec_idx = 0; vec_idx < uiop->uio_iovcnt &&
                            offset >= uiop->uio_iov[vec_idx].iov_len;
                            offset -= uiop->uio_iov[vec_idx++].iov_len)
                                ;
                        if (vec_idx == uiop->uio_iovcnt) {
                                return (CRYPTO_DATA_LEN_RANGE);
                        }

                        /*
                         * Now process the iovecs.
                         */
                        while (vec_idx < uiop->uio_iovcnt && length > 0) {
                                uchar_t *start;
                                iovec_t *iovp = &(uiop->uio_iov[vec_idx]);

                                cur_len = MIN(iovp->iov_len - offset, length);

                                start = (uchar_t *)(iovp->iov_base + offset);
                                arcfour_crypt(key, start + offset,
                                    start + offset, cur_len);

                                length -= cur_len;
                                vec_idx++;
                                offset = 0;
                        }

                        if (vec_idx == uiop->uio_iovcnt && length > 0) {

                                return (CRYPTO_DATA_LEN_RANGE);
                        }
                        break;
                }
                }
                return (CRYPTO_SUCCESS);
        }

        /*
         * We need to just return the length needed to store the output.
         * We should not destroy the context for the following case.
         */

        if (input->cd_length > output->cd_length) {
                output->cd_length = input->cd_length;
                return (CRYPTO_BUFFER_TOO_SMALL);
        }

        saveoffset = output->cd_offset;

        switch (input->cd_format) {
        case CRYPTO_DATA_RAW: {
                char *start, *end;
                start = input->cd_raw.iov_base + input->cd_offset;

                end =  input->cd_raw.iov_base + input->cd_raw.iov_len;

                if (start + input->cd_length > end)
                        return (CRYPTO_DATA_LEN_RANGE);

                ret = crypto_arcfour_crypt(key, (uchar_t *)start, output,
                    input->cd_length);

                if (ret != CRYPTO_SUCCESS)
                        return (ret);
                break;
        }
        case CRYPTO_DATA_MBLK: {
                uchar_t *start, *end;
                size_t len, left;
                mblk_t *mp = input->cd_mp, *mp1, *mp2;

                ASSERT(mp != NULL);

                mp1 = advance_position(mp, input->cd_offset, &start);

                if (mp1 == NULL)
                        return (CRYPTO_DATA_LEN_RANGE);

                mp2 = advance_position(mp, input->cd_offset + input->cd_length,
                    &end);

                if (mp2 == NULL)
                        return (CRYPTO_DATA_LEN_RANGE);

                left = input->cd_length;
                while (mp1 != NULL) {
                        if (_PTRDIFF(mp1->b_wptr, start) > left) {
                                len = left;
                                ret = crypto_arcfour_crypt(key, start, output,
                                    len);
                                if (ret != CRYPTO_SUCCESS)
                                        return (ret);
                                mp1 = NULL;
                        } else {
                                len = _PTRDIFF(mp1->b_wptr, start);
                                ret = crypto_arcfour_crypt(key, start, output,
                                    len);
                                if (ret != CRYPTO_SUCCESS)
                                        return (ret);
                                mp1 = mp1->b_cont;
                                start = mp1->b_rptr;
                                left -= len;
                                output->cd_offset += len;
                        }
                }
                break;
        }
        case CRYPTO_DATA_UIO: {
                uio_t *uiop = input->cd_uio;
                off_t offset = input->cd_offset;
                size_t length = input->cd_length;
                uint_t vec_idx;
                size_t cur_len;

                /*
                 * Jump to the first iovec containing data to be
                 * processed.
                 */
                for (vec_idx = 0; vec_idx < uiop->uio_iovcnt &&
                    offset >= uiop->uio_iov[vec_idx].iov_len;
                    offset -= uiop->uio_iov[vec_idx++].iov_len)
                        ;
                if (vec_idx == uiop->uio_iovcnt) {
                        return (CRYPTO_DATA_LEN_RANGE);
                }

                /*
                 * Now process the iovecs.
                 */
                while (vec_idx < uiop->uio_iovcnt && length > 0) {
                        uchar_t *start;
                        iovec_t *iovp = &(uiop->uio_iov[vec_idx]);
                        cur_len = MIN(iovp->iov_len - offset, length);

                        start = (uchar_t *)(iovp->iov_base + offset);
                        ret = crypto_arcfour_crypt(key, start + offset,
                            output, cur_len);
                        if (ret != CRYPTO_SUCCESS)
                                return (ret);

                        length -= cur_len;
                        vec_idx++;
                        offset = 0;
                        output->cd_offset += cur_len;
                }

                if (vec_idx == uiop->uio_iovcnt && length > 0) {

                        return (CRYPTO_DATA_LEN_RANGE);
                }
        }
        }

        output->cd_offset = saveoffset;
        output->cd_length = input->cd_length;

        return (ret);
}

/* ARGSUSED */
static int rc4_crypt_final(crypto_ctx_t *ctx, crypto_data_t *data,
    crypto_req_handle_t req)
{
        /* No final part for streams ciphers. Just free the context */
        if (data != NULL)
                data->cd_length = 0;

        return (rc4_free_context(ctx));
}

/* ARGSUSED */
static int
rc4_crypt_atomic(crypto_provider_handle_t handle, crypto_session_id_t session,
    crypto_mechanism_t *mechanism, crypto_key_t *key, crypto_data_t *input,
    crypto_data_t *output, crypto_spi_ctx_template_t template,
    crypto_req_handle_t req)
{
        crypto_ctx_t ctx;
        int ret;

        bzero(&ctx, sizeof (crypto_ctx_t));
        ret = rc4_common_init(&ctx, mechanism, key, template, req);

        if (ret != CRYPTO_SUCCESS)
                return (ret);

        ret = rc4_crypt_update(&ctx, input, output, req);

        (void) rc4_free_context(&ctx);

        return (ret);
}

/* ARGSUSED */
static int
rc4_free_context(crypto_ctx_t *ctx)
{
        ARCFour_key *keystream = ctx->cc_provider_private;

        if (keystream != NULL) {
                bzero(keystream, sizeof (ARCFour_key));
                kmem_free(keystream, sizeof (ARCFour_key));
                ctx->cc_provider_private = NULL;
        }

        return (CRYPTO_SUCCESS);
}

/* Encrypts a contiguous input 'in' into the 'out' crypto_data_t */

static int
crypto_arcfour_crypt(ARCFour_key *key, uchar_t *in, crypto_data_t *out,
    int length)
{
        switch (out->cd_format) {
                case CRYPTO_DATA_RAW: {
                        uchar_t *start, *end;
                        start = (uchar_t *)(out->cd_raw.iov_base +
                            out->cd_offset);

                        end = (uchar_t *)(out->cd_raw.iov_base +
                            out->cd_raw.iov_len);

                        if (start + out->cd_length > end)
                                return (CRYPTO_DATA_LEN_RANGE);

                        arcfour_crypt(key, in, start, length);

                        return (CRYPTO_SUCCESS);
                }
                case CRYPTO_DATA_MBLK: {
                        uchar_t *start, *end;
                        size_t len, left;
                        mblk_t *mp = out->cd_mp, *mp1, *mp2;

                        ASSERT(mp != NULL);

                        mp1 = advance_position(mp, out->cd_offset, &start);

                        if (mp1 == NULL)
                                return (CRYPTO_DATA_LEN_RANGE);

                        mp2 = advance_position(mp, out->cd_offset +
                            out->cd_length, &end);

                        if (mp2 == NULL)
                                return (CRYPTO_DATA_LEN_RANGE);

                        left = length;
                        while (mp1 != NULL) {
                                if (_PTRDIFF(mp1->b_wptr, start) > left) {
                                        len = left;
                                        arcfour_crypt(key, in, start, len);
                                        mp1 = NULL;
                                } else {
                                        len = _PTRDIFF(mp1->b_wptr, start);
                                        arcfour_crypt(key, in, start, len);
                                        mp1 = mp1->b_cont;
                                        start = mp1->b_rptr;
                                        left -= len;
                                }
                        }
                        break;
                }
                case CRYPTO_DATA_UIO: {
                        uio_t *uiop = out->cd_uio;
                        off_t offset = out->cd_offset;
                        size_t len = length;
                        uint_t vec_idx;
                        size_t cur_len;

                        /*
                         * Jump to the first iovec containing data to be
                         * processed.
                         */
                        for (vec_idx = 0; vec_idx < uiop->uio_iovcnt &&
                            offset >= uiop->uio_iov[vec_idx].iov_len;
                            offset -= uiop->uio_iov[vec_idx++].iov_len)
                                ;
                        if (vec_idx == uiop->uio_iovcnt) {
                                return (CRYPTO_DATA_LEN_RANGE);
                        }

                        /*
                         * Now process the iovecs.
                         */
                        while (vec_idx < uiop->uio_iovcnt && len > 0) {
                                uchar_t *start;
                                iovec_t *iovp = &(uiop->uio_iov[vec_idx]);
                                cur_len = MIN(iovp->iov_len - offset, len);

                                start = (uchar_t *)(iovp->iov_base + offset);
                                arcfour_crypt(key, start + offset,
                                    start + offset, cur_len);

                                len -= cur_len;
                                vec_idx++;
                                offset = 0;
                        }

                        if (vec_idx == uiop->uio_iovcnt && len > 0) {
                                return (CRYPTO_DATA_LEN_RANGE);
                        }
                        break;
                }
                default:
                        return (CRYPTO_DATA_INVALID);
        }
        return (CRYPTO_SUCCESS);
}

/*
 * Advances 'offset' bytes from the beginning of the first block in 'mp',
 * possibly jumping across b_cont boundary
 * '*cpp' is set to the position of the byte we want, and the block where
 * 'cpp' is returned.
 */
static mblk_t *
advance_position(mblk_t *mp, off_t offset, uchar_t **cpp)
{
        mblk_t *mp1 = mp;
        size_t l;
        off_t o = offset;

        while (mp1 != NULL) {
                l = MBLKL(mp1);

                if (l <= o) {
                        o -= l;
                        mp1 = mp1->b_cont;
                } else {
                        *cpp = (uchar_t *)(mp1->b_rptr + o);
                        break;
                }
        }
        return (mp1);
}