// SPDX-License-Identifier: GPL-2.0-only
/*
 * AMD Cryptographic Coprocessor (CCP) SHA crypto API support
 *
 * Copyright (C) 2013,2018 Advanced Micro Devices, Inc.
 *
 * Author: Tom Lendacky <thomas.lendacky@amd.com>
 * Author: Gary R Hook <gary.hook@amd.com>
 */

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/scatterlist.h>
#include <linux/crypto.h>
#include <crypto/algapi.h>
#include <crypto/hash.h>
#include <crypto/hmac.h>
#include <crypto/internal/hash.h>
#include <crypto/sha1.h>
#include <crypto/sha2.h>
#include <crypto/scatterwalk.h>
#include <linux/string.h>

#include "ccp-crypto.h"

static int ccp_sha_complete(struct crypto_async_request *async_req, int ret)
{
        struct ahash_request *req = ahash_request_cast(async_req);
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
        struct ccp_sha_req_ctx *rctx = ahash_request_ctx_dma(req);
        unsigned int digest_size = crypto_ahash_digestsize(tfm);

        if (ret)
                goto e_free;

        if (rctx->hash_rem) {
                /* Save remaining data to buffer */
                unsigned int offset = rctx->nbytes - rctx->hash_rem;

                scatterwalk_map_and_copy(rctx->buf, rctx->src,
                                         offset, rctx->hash_rem, 0);
                rctx->buf_count = rctx->hash_rem;
        } else {
                rctx->buf_count = 0;
        }

        /* Update result area if supplied */
        if (req->result && rctx->final)
                memcpy(req->result, rctx->ctx, digest_size);

e_free:
        sg_free_table(&rctx->data_sg);

        return ret;
}

static int ccp_do_sha_update(struct ahash_request *req, unsigned int nbytes,
                             unsigned int final)
{
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
        struct ccp_ctx *ctx = crypto_ahash_ctx_dma(tfm);
        struct ccp_sha_req_ctx *rctx = ahash_request_ctx_dma(req);
        struct scatterlist *sg;
        unsigned int block_size =
                crypto_tfm_alg_blocksize(crypto_ahash_tfm(tfm));
        unsigned int sg_count;
        gfp_t gfp;
        u64 len;
        int ret;

        len = (u64)rctx->buf_count + (u64)nbytes;

        if (!final && (len <= block_size)) {
                scatterwalk_map_and_copy(rctx->buf + rctx->buf_count, req->src,
                                         0, nbytes, 0);
                rctx->buf_count += nbytes;

                return 0;
        }

        rctx->src = req->src;
        rctx->nbytes = nbytes;

        rctx->final = final;
        rctx->hash_rem = final ? 0 : len & (block_size - 1);
        rctx->hash_cnt = len - rctx->hash_rem;
        if (!final && !rctx->hash_rem) {
                /* CCP can't do zero length final, so keep some data around */
                rctx->hash_cnt -= block_size;
                rctx->hash_rem = block_size;
        }

        /* Initialize the context scatterlist */
        sg_init_one(&rctx->ctx_sg, rctx->ctx, sizeof(rctx->ctx));

        sg = NULL;
        if (rctx->buf_count && nbytes) {
                /* Build the data scatterlist table - allocate enough entries
                 * for both data pieces (buffer and input data)
                 */
                gfp = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ?
                        GFP_KERNEL : GFP_ATOMIC;
                sg_count = sg_nents(req->src) + 1;
                ret = sg_alloc_table(&rctx->data_sg, sg_count, gfp);
                if (ret)
                        return ret;

                sg_init_one(&rctx->buf_sg, rctx->buf, rctx->buf_count);
                sg = ccp_crypto_sg_table_add(&rctx->data_sg, &rctx->buf_sg);
                if (!sg) {
                        ret = -EINVAL;
                        goto e_free;
                }
                sg = ccp_crypto_sg_table_add(&rctx->data_sg, req->src);
                if (!sg) {
                        ret = -EINVAL;
                        goto e_free;
                }
                sg_mark_end(sg);

                sg = rctx->data_sg.sgl;
        } else if (rctx->buf_count) {
                sg_init_one(&rctx->buf_sg, rctx->buf, rctx->buf_count);

                sg = &rctx->buf_sg;
        } else if (nbytes) {
                sg = req->src;
        }

        rctx->msg_bits += (rctx->hash_cnt << 3);        /* Total in bits */

        memset(&rctx->cmd, 0, sizeof(rctx->cmd));
        INIT_LIST_HEAD(&rctx->cmd.entry);
        rctx->cmd.engine = CCP_ENGINE_SHA;
        rctx->cmd.u.sha.type = rctx->type;
        rctx->cmd.u.sha.ctx = &rctx->ctx_sg;

        switch (rctx->type) {
        case CCP_SHA_TYPE_1:
                rctx->cmd.u.sha.ctx_len = SHA1_DIGEST_SIZE;
                break;
        case CCP_SHA_TYPE_224:
                rctx->cmd.u.sha.ctx_len = SHA224_DIGEST_SIZE;
                break;
        case CCP_SHA_TYPE_256:
                rctx->cmd.u.sha.ctx_len = SHA256_DIGEST_SIZE;
                break;
        case CCP_SHA_TYPE_384:
                rctx->cmd.u.sha.ctx_len = SHA384_DIGEST_SIZE;
                break;
        case CCP_SHA_TYPE_512:
                rctx->cmd.u.sha.ctx_len = SHA512_DIGEST_SIZE;
                break;
        default:
                /* Should never get here */
                break;
        }

        rctx->cmd.u.sha.src = sg;
        rctx->cmd.u.sha.src_len = rctx->hash_cnt;
        rctx->cmd.u.sha.opad = ctx->u.sha.key_len ?
                &ctx->u.sha.opad_sg : NULL;
        rctx->cmd.u.sha.opad_len = ctx->u.sha.key_len ?
                ctx->u.sha.opad_count : 0;
        rctx->cmd.u.sha.first = rctx->first;
        rctx->cmd.u.sha.final = rctx->final;
        rctx->cmd.u.sha.msg_bits = rctx->msg_bits;

        rctx->first = 0;

        ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);

        return ret;

e_free:
        sg_free_table(&rctx->data_sg);

        return ret;
}

static int ccp_sha_init(struct ahash_request *req)
{
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
        struct ccp_ctx *ctx = crypto_ahash_ctx_dma(tfm);
        struct ccp_sha_req_ctx *rctx = ahash_request_ctx_dma(req);
        struct ccp_crypto_ahash_alg *alg =
                ccp_crypto_ahash_alg(crypto_ahash_tfm(tfm));
        unsigned int block_size =
                crypto_tfm_alg_blocksize(crypto_ahash_tfm(tfm));

        memset(rctx, 0, sizeof(*rctx));

        rctx->type = alg->type;
        rctx->first = 1;

        if (ctx->u.sha.key_len) {
                /* Buffer the HMAC key for first update */
                memcpy(rctx->buf, ctx->u.sha.ipad, block_size);
                rctx->buf_count = block_size;
        }

        return 0;
}

static int ccp_sha_update(struct ahash_request *req)
{
        return ccp_do_sha_update(req, req->nbytes, 0);
}

static int ccp_sha_final(struct ahash_request *req)
{
        return ccp_do_sha_update(req, 0, 1);
}

static int ccp_sha_finup(struct ahash_request *req)
{
        return ccp_do_sha_update(req, req->nbytes, 1);
}

static int ccp_sha_digest(struct ahash_request *req)
{
        int ret;

        ret = ccp_sha_init(req);
        if (ret)
                return ret;

        return ccp_sha_finup(req);
}

static int ccp_sha_export(struct ahash_request *req, void *out)
{
        struct ccp_sha_req_ctx *rctx = ahash_request_ctx_dma(req);
        struct ccp_sha_exp_ctx state;

        /* Don't let anything leak to 'out' */
        memset(&state, 0, sizeof(state));

        state.type = rctx->type;
        state.msg_bits = rctx->msg_bits;
        state.first = rctx->first;
        memcpy(state.ctx, rctx->ctx, sizeof(state.ctx));
        state.buf_count = rctx->buf_count;
        memcpy(state.buf, rctx->buf, sizeof(state.buf));

        /* 'out' may not be aligned so memcpy from local variable */
        memcpy(out, &state, sizeof(state));

        return 0;
}

static int ccp_sha_import(struct ahash_request *req, const void *in)
{
        struct ccp_sha_req_ctx *rctx = ahash_request_ctx_dma(req);
        struct ccp_sha_exp_ctx state;

        /* 'in' may not be aligned so memcpy to local variable */
        memcpy(&state, in, sizeof(state));

        memset(rctx, 0, sizeof(*rctx));
        rctx->type = state.type;
        rctx->msg_bits = state.msg_bits;
        rctx->first = state.first;
        memcpy(rctx->ctx, state.ctx, sizeof(rctx->ctx));
        rctx->buf_count = state.buf_count;
        memcpy(rctx->buf, state.buf, sizeof(rctx->buf));

        return 0;
}

static int ccp_sha_setkey(struct crypto_ahash *tfm, const u8 *key,
                          unsigned int key_len)
{
        struct ccp_ctx *ctx = crypto_ahash_ctx_dma(tfm);
        struct crypto_shash *shash = ctx->u.sha.hmac_tfm;
        unsigned int block_size = crypto_shash_blocksize(shash);
        unsigned int digest_size = crypto_shash_digestsize(shash);
        int i, ret;

        /* Set to zero until complete */
        ctx->u.sha.key_len = 0;

        /* Clear key area to provide zero padding for keys smaller
         * than the block size
         */
        memset(ctx->u.sha.key, 0, sizeof(ctx->u.sha.key));

        if (key_len > block_size) {
                /* Must hash the input key */
                ret = crypto_shash_tfm_digest(shash, key, key_len,
                                              ctx->u.sha.key);
                if (ret)
                        return -EINVAL;

                key_len = digest_size;
        } else {
                memcpy(ctx->u.sha.key, key, key_len);
        }

        for (i = 0; i < block_size; i++) {
                ctx->u.sha.ipad[i] = ctx->u.sha.key[i] ^ HMAC_IPAD_VALUE;
                ctx->u.sha.opad[i] = ctx->u.sha.key[i] ^ HMAC_OPAD_VALUE;
        }

        sg_init_one(&ctx->u.sha.opad_sg, ctx->u.sha.opad, block_size);
        ctx->u.sha.opad_count = block_size;

        ctx->u.sha.key_len = key_len;

        return 0;
}

static int ccp_sha_cra_init(struct crypto_tfm *tfm)
{
        struct crypto_ahash *ahash = __crypto_ahash_cast(tfm);
        struct ccp_ctx *ctx = crypto_ahash_ctx_dma(ahash);

        ctx->complete = ccp_sha_complete;
        ctx->u.sha.key_len = 0;

        crypto_ahash_set_reqsize_dma(ahash, sizeof(struct ccp_sha_req_ctx));

        return 0;
}

static void ccp_sha_cra_exit(struct crypto_tfm *tfm)
{
}

static int ccp_hmac_sha_cra_init(struct crypto_tfm *tfm)
{
        struct ccp_ctx *ctx = crypto_tfm_ctx_dma(tfm);
        struct ccp_crypto_ahash_alg *alg = ccp_crypto_ahash_alg(tfm);
        struct crypto_shash *hmac_tfm;

        hmac_tfm = crypto_alloc_shash(alg->child_alg, 0, 0);
        if (IS_ERR(hmac_tfm)) {
                pr_warn("could not load driver %s need for HMAC support\n",
                        alg->child_alg);
                return PTR_ERR(hmac_tfm);
        }

        ctx->u.sha.hmac_tfm = hmac_tfm;

        return ccp_sha_cra_init(tfm);
}

static void ccp_hmac_sha_cra_exit(struct crypto_tfm *tfm)
{
        struct ccp_ctx *ctx = crypto_tfm_ctx_dma(tfm);

        if (ctx->u.sha.hmac_tfm)
                crypto_free_shash(ctx->u.sha.hmac_tfm);

        ccp_sha_cra_exit(tfm);
}

struct ccp_sha_def {
        unsigned int version;
        const char *name;
        const char *drv_name;
        enum ccp_sha_type type;
        u32 digest_size;
        u32 block_size;
};

static struct ccp_sha_def sha_algs[] = {
        {
                .version        = CCP_VERSION(3, 0),
                .name           = "sha1",
                .drv_name       = "sha1-ccp",
                .type           = CCP_SHA_TYPE_1,
                .digest_size    = SHA1_DIGEST_SIZE,
                .block_size     = SHA1_BLOCK_SIZE,
        },
        {
                .version        = CCP_VERSION(3, 0),
                .name           = "sha224",
                .drv_name       = "sha224-ccp",
                .type           = CCP_SHA_TYPE_224,
                .digest_size    = SHA224_DIGEST_SIZE,
                .block_size     = SHA224_BLOCK_SIZE,
        },
        {
                .version        = CCP_VERSION(3, 0),
                .name           = "sha256",
                .drv_name       = "sha256-ccp",
                .type           = CCP_SHA_TYPE_256,
                .digest_size    = SHA256_DIGEST_SIZE,
                .block_size     = SHA256_BLOCK_SIZE,
        },
        {
                .version        = CCP_VERSION(5, 0),
                .name           = "sha384",
                .drv_name       = "sha384-ccp",
                .type           = CCP_SHA_TYPE_384,
                .digest_size    = SHA384_DIGEST_SIZE,
                .block_size     = SHA384_BLOCK_SIZE,
        },
        {
                .version        = CCP_VERSION(5, 0),
                .name           = "sha512",
                .drv_name       = "sha512-ccp",
                .type           = CCP_SHA_TYPE_512,
                .digest_size    = SHA512_DIGEST_SIZE,
                .block_size     = SHA512_BLOCK_SIZE,
        },
};

static int ccp_register_hmac_alg(struct list_head *head,
                                 const struct ccp_sha_def *def,
                                 const struct ccp_crypto_ahash_alg *base_alg)
{
        struct ccp_crypto_ahash_alg *ccp_alg;
        struct ahash_alg *alg;
        struct hash_alg_common *halg;
        struct crypto_alg *base;
        int ret;

        ccp_alg = kzalloc_obj(*ccp_alg);
        if (!ccp_alg)
                return -ENOMEM;

        /* Copy the base algorithm and only change what's necessary */
        *ccp_alg = *base_alg;
        INIT_LIST_HEAD(&ccp_alg->entry);

        strscpy(ccp_alg->child_alg, def->name, CRYPTO_MAX_ALG_NAME);

        alg = &ccp_alg->alg;
        alg->setkey = ccp_sha_setkey;

        halg = &alg->halg;

        base = &halg->base;
        snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME, "hmac(%s)", def->name);
        snprintf(base->cra_driver_name, CRYPTO_MAX_ALG_NAME, "hmac-%s",
                 def->drv_name);
        base->cra_init = ccp_hmac_sha_cra_init;
        base->cra_exit = ccp_hmac_sha_cra_exit;

        ret = crypto_register_ahash(alg);
        if (ret) {
                pr_err("%s ahash algorithm registration error (%d)\n",
                       base->cra_name, ret);
                kfree(ccp_alg);
                return ret;
        }

        list_add(&ccp_alg->entry, head);

        return ret;
}

static int ccp_register_sha_alg(struct list_head *head,
                                const struct ccp_sha_def *def)
{
        struct ccp_crypto_ahash_alg *ccp_alg;
        struct ahash_alg *alg;
        struct hash_alg_common *halg;
        struct crypto_alg *base;
        int ret;

        ccp_alg = kzalloc_obj(*ccp_alg);
        if (!ccp_alg)
                return -ENOMEM;

        INIT_LIST_HEAD(&ccp_alg->entry);

        ccp_alg->type = def->type;

        alg = &ccp_alg->alg;
        alg->init = ccp_sha_init;
        alg->update = ccp_sha_update;
        alg->final = ccp_sha_final;
        alg->finup = ccp_sha_finup;
        alg->digest = ccp_sha_digest;
        alg->export = ccp_sha_export;
        alg->import = ccp_sha_import;

        halg = &alg->halg;
        halg->digestsize = def->digest_size;
        halg->statesize = sizeof(struct ccp_sha_exp_ctx);

        base = &halg->base;
        snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name);
        snprintf(base->cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s",
                 def->drv_name);
        base->cra_flags = CRYPTO_ALG_ASYNC |
                          CRYPTO_ALG_ALLOCATES_MEMORY |
                          CRYPTO_ALG_KERN_DRIVER_ONLY |
                          CRYPTO_ALG_NEED_FALLBACK;
        base->cra_blocksize = def->block_size;
        base->cra_ctxsize = sizeof(struct ccp_ctx) + crypto_dma_padding();
        base->cra_priority = CCP_CRA_PRIORITY;
        base->cra_init = ccp_sha_cra_init;
        base->cra_exit = ccp_sha_cra_exit;
        base->cra_module = THIS_MODULE;

        ret = crypto_register_ahash(alg);
        if (ret) {
                pr_err("%s ahash algorithm registration error (%d)\n",
                       base->cra_name, ret);
                kfree(ccp_alg);
                return ret;
        }

        list_add(&ccp_alg->entry, head);

        ret = ccp_register_hmac_alg(head, def, ccp_alg);

        return ret;
}

int ccp_register_sha_algs(struct list_head *head)
{
        int i, ret;
        unsigned int ccpversion = ccp_version();

        for (i = 0; i < ARRAY_SIZE(sha_algs); i++) {
                if (sha_algs[i].version > ccpversion)
                        continue;
                ret = ccp_register_sha_alg(head, &sha_algs[i]);
                if (ret)
                        return ret;
        }

        return 0;
}