// SPDX-License-Identifier: GPL-2.0-or-later
 /* Algorithms supported by virtio crypto device
  *
  * Authors: Gonglei <arei.gonglei@huawei.com>
  *
  * Copyright 2016 HUAWEI TECHNOLOGIES CO., LTD.
  */

#include <crypto/engine.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/scatterlist.h>
#include <uapi/linux/virtio_crypto.h>
#include "virtio_crypto_common.h"


struct virtio_crypto_skcipher_ctx {
        struct virtio_crypto *vcrypto;

        struct virtio_crypto_sym_session_info enc_sess_info;
        struct virtio_crypto_sym_session_info dec_sess_info;
};

struct virtio_crypto_sym_request {
        struct virtio_crypto_request base;

        /* Cipher or aead */
        uint32_t type;
        uint8_t *iv;
        /* Encryption? */
        bool encrypt;
};

struct virtio_crypto_algo {
        uint32_t algonum;
        uint32_t service;
        unsigned int active_devs;
        struct skcipher_engine_alg algo;
};

/*
 * The algs_lock protects the below global virtio_crypto_active_devs
 * and crypto algorithms registion.
 */
static DEFINE_MUTEX(algs_lock);
static void virtio_crypto_skcipher_finalize_req(
        struct virtio_crypto_sym_request *vc_sym_req,
        struct skcipher_request *req,
        int err);

static void virtio_crypto_dataq_sym_callback
                (struct virtio_crypto_request *vc_req, int len)
{
        struct virtio_crypto_sym_request *vc_sym_req =
                container_of(vc_req, struct virtio_crypto_sym_request, base);
        struct skcipher_request *ablk_req =
                container_of((void *)vc_sym_req, struct skcipher_request,
                             __ctx);
        int error;

        /* Finish the encrypt or decrypt process */
        if (vc_sym_req->type == VIRTIO_CRYPTO_SYM_OP_CIPHER) {
                switch (vc_req->status) {
                case VIRTIO_CRYPTO_OK:
                        error = 0;
                        break;
                case VIRTIO_CRYPTO_INVSESS:
                case VIRTIO_CRYPTO_ERR:
                        error = -EINVAL;
                        break;
                case VIRTIO_CRYPTO_BADMSG:
                        error = -EBADMSG;
                        break;
                default:
                        error = -EIO;
                        break;
                }
                virtio_crypto_skcipher_finalize_req(vc_sym_req,
                                                        ablk_req, error);
        }
}

static u64 virtio_crypto_alg_sg_nents_length(struct scatterlist *sg)
{
        u64 total = 0;

        for (total = 0; sg; sg = sg_next(sg))
                total += sg->length;

        return total;
}

static int
virtio_crypto_alg_validate_key(int key_len, uint32_t *alg)
{
        switch (key_len) {
        case AES_KEYSIZE_128:
        case AES_KEYSIZE_192:
        case AES_KEYSIZE_256:
                *alg = VIRTIO_CRYPTO_CIPHER_AES_CBC;
                break;
        default:
                return -EINVAL;
        }
        return 0;
}

static int virtio_crypto_alg_skcipher_init_session(
                struct virtio_crypto_skcipher_ctx *ctx,
                uint32_t alg, const uint8_t *key,
                unsigned int keylen,
                int encrypt)
{
        struct scatterlist outhdr, key_sg, inhdr, *sgs[3];
        struct virtio_crypto *vcrypto = ctx->vcrypto;
        int op = encrypt ? VIRTIO_CRYPTO_OP_ENCRYPT : VIRTIO_CRYPTO_OP_DECRYPT;
        int err;
        unsigned int num_out = 0, num_in = 0;
        struct virtio_crypto_op_ctrl_req *ctrl;
        struct virtio_crypto_session_input *input;
        struct virtio_crypto_sym_create_session_req *sym_create_session;
        struct virtio_crypto_ctrl_request *vc_ctrl_req;

        /*
         * Avoid to do DMA from the stack, switch to using
         * dynamically-allocated for the key
         */
        uint8_t *cipher_key = kmemdup(key, keylen, GFP_ATOMIC);

        if (!cipher_key)
                return -ENOMEM;

        vc_ctrl_req = kzalloc_obj(*vc_ctrl_req);
        if (!vc_ctrl_req) {
                err = -ENOMEM;
                goto out;
        }

        /* Pad ctrl header */
        ctrl = &vc_ctrl_req->ctrl;
        ctrl->header.opcode = cpu_to_le32(VIRTIO_CRYPTO_CIPHER_CREATE_SESSION);
        ctrl->header.algo = cpu_to_le32(alg);
        /* Set the default dataqueue id to 0 */
        ctrl->header.queue_id = 0;

        input = &vc_ctrl_req->input;
        input->status = cpu_to_le32(VIRTIO_CRYPTO_ERR);
        /* Pad cipher's parameters */
        sym_create_session = &ctrl->u.sym_create_session;
        sym_create_session->op_type = cpu_to_le32(VIRTIO_CRYPTO_SYM_OP_CIPHER);
        sym_create_session->u.cipher.para.algo = ctrl->header.algo;
        sym_create_session->u.cipher.para.keylen = cpu_to_le32(keylen);
        sym_create_session->u.cipher.para.op = cpu_to_le32(op);

        sg_init_one(&outhdr, ctrl, sizeof(*ctrl));
        sgs[num_out++] = &outhdr;

        /* Set key */
        sg_init_one(&key_sg, cipher_key, keylen);
        sgs[num_out++] = &key_sg;

        /* Return status and session id back */
        sg_init_one(&inhdr, input, sizeof(*input));
        sgs[num_out + num_in++] = &inhdr;

        err = virtio_crypto_ctrl_vq_request(vcrypto, sgs, num_out, num_in, vc_ctrl_req);
        if (err < 0)
                goto out;

        if (le32_to_cpu(input->status) != VIRTIO_CRYPTO_OK) {
                pr_err("virtio_crypto: Create session failed status: %u\n",
                        le32_to_cpu(input->status));
                err = -EINVAL;
                goto out;
        }

        if (encrypt)
                ctx->enc_sess_info.session_id = le64_to_cpu(input->session_id);
        else
                ctx->dec_sess_info.session_id = le64_to_cpu(input->session_id);

        err = 0;
out:
        kfree(vc_ctrl_req);
        kfree_sensitive(cipher_key);
        return err;
}

static int virtio_crypto_alg_skcipher_close_session(
                struct virtio_crypto_skcipher_ctx *ctx,
                int encrypt)
{
        struct scatterlist outhdr, status_sg, *sgs[2];
        struct virtio_crypto_destroy_session_req *destroy_session;
        struct virtio_crypto *vcrypto = ctx->vcrypto;
        int err;
        unsigned int num_out = 0, num_in = 0;
        struct virtio_crypto_op_ctrl_req *ctrl;
        struct virtio_crypto_inhdr *ctrl_status;
        struct virtio_crypto_ctrl_request *vc_ctrl_req;

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

        ctrl_status = &vc_ctrl_req->ctrl_status;
        ctrl_status->status = VIRTIO_CRYPTO_ERR;
        /* Pad ctrl header */
        ctrl = &vc_ctrl_req->ctrl;
        ctrl->header.opcode = cpu_to_le32(VIRTIO_CRYPTO_CIPHER_DESTROY_SESSION);
        /* Set the default virtqueue id to 0 */
        ctrl->header.queue_id = 0;

        destroy_session = &ctrl->u.destroy_session;

        if (encrypt)
                destroy_session->session_id = cpu_to_le64(ctx->enc_sess_info.session_id);
        else
                destroy_session->session_id = cpu_to_le64(ctx->dec_sess_info.session_id);

        sg_init_one(&outhdr, ctrl, sizeof(*ctrl));
        sgs[num_out++] = &outhdr;

        /* Return status and session id back */
        sg_init_one(&status_sg, &ctrl_status->status, sizeof(ctrl_status->status));
        sgs[num_out + num_in++] = &status_sg;

        err = virtio_crypto_ctrl_vq_request(vcrypto, sgs, num_out, num_in, vc_ctrl_req);
        if (err < 0)
                goto out;

        if (ctrl_status->status != VIRTIO_CRYPTO_OK) {
                pr_err("virtio_crypto: Close session failed status: %u, session_id: 0x%llx\n",
                        ctrl_status->status, destroy_session->session_id);

                err = -EINVAL;
                goto out;
        }

        err = 0;
out:
        kfree(vc_ctrl_req);
        return err;
}

static int virtio_crypto_alg_skcipher_init_sessions(
                struct virtio_crypto_skcipher_ctx *ctx,
                const uint8_t *key, unsigned int keylen)
{
        uint32_t alg;
        int ret;
        struct virtio_crypto *vcrypto = ctx->vcrypto;

        if (keylen > vcrypto->max_cipher_key_len) {
                pr_err("virtio_crypto: the key is too long\n");
                return -EINVAL;
        }

        if (virtio_crypto_alg_validate_key(keylen, &alg))
                return -EINVAL;

        /* Create encryption session */
        ret = virtio_crypto_alg_skcipher_init_session(ctx,
                        alg, key, keylen, 1);
        if (ret)
                return ret;
        /* Create decryption session */
        ret = virtio_crypto_alg_skcipher_init_session(ctx,
                        alg, key, keylen, 0);
        if (ret) {
                virtio_crypto_alg_skcipher_close_session(ctx, 1);
                return ret;
        }
        return 0;
}

/* Note: kernel crypto API realization */
static int virtio_crypto_skcipher_setkey(struct crypto_skcipher *tfm,
                                         const uint8_t *key,
                                         unsigned int keylen)
{
        struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
        uint32_t alg;
        int ret;

        ret = virtio_crypto_alg_validate_key(keylen, &alg);
        if (ret)
                return ret;

        if (!ctx->vcrypto) {
                /* New key */
                int node = virtio_crypto_get_current_node();
                struct virtio_crypto *vcrypto =
                                      virtcrypto_get_dev_node(node,
                                      VIRTIO_CRYPTO_SERVICE_CIPHER, alg);
                if (!vcrypto) {
                        pr_err("virtio_crypto: Could not find a virtio device in the system or unsupported algo\n");
                        return -ENODEV;
                }

                ctx->vcrypto = vcrypto;
        } else {
                /* Rekeying, we should close the created sessions previously */
                virtio_crypto_alg_skcipher_close_session(ctx, 1);
                virtio_crypto_alg_skcipher_close_session(ctx, 0);
        }

        ret = virtio_crypto_alg_skcipher_init_sessions(ctx, key, keylen);
        if (ret) {
                virtcrypto_dev_put(ctx->vcrypto);
                ctx->vcrypto = NULL;

                return ret;
        }

        return 0;
}

static int
__virtio_crypto_skcipher_do_req(struct virtio_crypto_sym_request *vc_sym_req,
                struct skcipher_request *req,
                struct data_queue *data_vq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
        struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
        struct virtio_crypto_request *vc_req = &vc_sym_req->base;
        unsigned int ivsize = crypto_skcipher_ivsize(tfm);
        struct virtio_crypto *vcrypto = ctx->vcrypto;
        struct virtio_crypto_op_data_req *req_data;
        int src_nents, dst_nents;
        int err;
        unsigned long flags;
        struct scatterlist outhdr, iv_sg, status_sg, **sgs;
        u64 dst_len;
        unsigned int num_out = 0, num_in = 0;
        int sg_total;
        uint8_t *iv;
        struct scatterlist *sg;

        src_nents = sg_nents_for_len(req->src, req->cryptlen);
        if (src_nents < 0) {
                pr_err("Invalid number of src SG.\n");
                return src_nents;
        }

        dst_nents = sg_nents(req->dst);

        pr_debug("virtio_crypto: Number of sgs (src_nents: %d, dst_nents: %d)\n",
                        src_nents, dst_nents);

        /* Why 3?  outhdr + iv + inhdr */
        sg_total = src_nents + dst_nents + 3;
        sgs = kcalloc_node(sg_total, sizeof(*sgs), GFP_KERNEL,
                                dev_to_node(&vcrypto->vdev->dev));
        if (!sgs)
                return -ENOMEM;

        req_data = kzalloc_node(sizeof(*req_data), GFP_KERNEL,
                                dev_to_node(&vcrypto->vdev->dev));
        if (!req_data) {
                kfree(sgs);
                return -ENOMEM;
        }

        vc_req->req_data = req_data;
        vc_sym_req->type = VIRTIO_CRYPTO_SYM_OP_CIPHER;
        /* Head of operation */
        if (vc_sym_req->encrypt) {
                req_data->header.session_id =
                        cpu_to_le64(ctx->enc_sess_info.session_id);
                req_data->header.opcode =
                        cpu_to_le32(VIRTIO_CRYPTO_CIPHER_ENCRYPT);
        } else {
                req_data->header.session_id =
                        cpu_to_le64(ctx->dec_sess_info.session_id);
                req_data->header.opcode =
                        cpu_to_le32(VIRTIO_CRYPTO_CIPHER_DECRYPT);
        }
        req_data->u.sym_req.op_type = cpu_to_le32(VIRTIO_CRYPTO_SYM_OP_CIPHER);
        req_data->u.sym_req.u.cipher.para.iv_len = cpu_to_le32(ivsize);
        req_data->u.sym_req.u.cipher.para.src_data_len =
                        cpu_to_le32(req->cryptlen);

        dst_len = virtio_crypto_alg_sg_nents_length(req->dst);
        if (unlikely(dst_len > U32_MAX)) {
                pr_err("virtio_crypto: The dst_len is beyond U32_MAX\n");
                err = -EINVAL;
                goto free;
        }

        dst_len = min_t(unsigned int, req->cryptlen, dst_len);
        pr_debug("virtio_crypto: src_len: %u, dst_len: %llu\n",
                        req->cryptlen, dst_len);

        if (unlikely(req->cryptlen + dst_len + ivsize +
                sizeof(vc_req->status) > vcrypto->max_size)) {
                pr_err("virtio_crypto: The length is too big\n");
                err = -EINVAL;
                goto free;
        }

        req_data->u.sym_req.u.cipher.para.dst_data_len =
                        cpu_to_le32((uint32_t)dst_len);

        /* Outhdr */
        sg_init_one(&outhdr, req_data, sizeof(*req_data));
        sgs[num_out++] = &outhdr;

        /* IV */

        /*
         * Avoid to do DMA from the stack, switch to using
         * dynamically-allocated for the IV
         */
        iv = kzalloc_node(ivsize, GFP_ATOMIC,
                                dev_to_node(&vcrypto->vdev->dev));
        if (!iv) {
                err = -ENOMEM;
                goto free;
        }
        memcpy(iv, req->iv, ivsize);
        if (!vc_sym_req->encrypt)
                scatterwalk_map_and_copy(req->iv, req->src,
                                         req->cryptlen - AES_BLOCK_SIZE,
                                         AES_BLOCK_SIZE, 0);

        sg_init_one(&iv_sg, iv, ivsize);
        sgs[num_out++] = &iv_sg;
        vc_sym_req->iv = iv;

        /* Source data */
        for (sg = req->src; src_nents; sg = sg_next(sg), src_nents--)
                sgs[num_out++] = sg;

        /* Destination data */
        for (sg = req->dst; sg; sg = sg_next(sg))
                sgs[num_out + num_in++] = sg;

        /* Status */
        sg_init_one(&status_sg, &vc_req->status, sizeof(vc_req->status));
        sgs[num_out + num_in++] = &status_sg;

        vc_req->sgs = sgs;

        spin_lock_irqsave(&data_vq->lock, flags);
        err = virtqueue_add_sgs(data_vq->vq, sgs, num_out,
                                num_in, vc_req, GFP_ATOMIC);
        virtqueue_kick(data_vq->vq);
        spin_unlock_irqrestore(&data_vq->lock, flags);
        if (unlikely(err < 0))
                goto free_iv;

        return 0;

free_iv:
        kfree_sensitive(iv);
free:
        kfree_sensitive(req_data);
        kfree(sgs);
        return err;
}

static int virtio_crypto_skcipher_encrypt(struct skcipher_request *req)
{
        struct crypto_skcipher *atfm = crypto_skcipher_reqtfm(req);
        struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(atfm);
        struct virtio_crypto_sym_request *vc_sym_req =
                                skcipher_request_ctx(req);
        struct virtio_crypto_request *vc_req = &vc_sym_req->base;
        struct virtio_crypto *vcrypto = ctx->vcrypto;
        /* Use the first data virtqueue as default */
        struct data_queue *data_vq = &vcrypto->data_vq[0];

        if (!req->cryptlen)
                return 0;
        if (req->cryptlen % AES_BLOCK_SIZE)
                return -EINVAL;

        vc_req->dataq = data_vq;
        vc_req->alg_cb = virtio_crypto_dataq_sym_callback;
        vc_sym_req->encrypt = true;

        return crypto_transfer_skcipher_request_to_engine(data_vq->engine, req);
}

static int virtio_crypto_skcipher_decrypt(struct skcipher_request *req)
{
        struct crypto_skcipher *atfm = crypto_skcipher_reqtfm(req);
        struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(atfm);
        struct virtio_crypto_sym_request *vc_sym_req =
                                skcipher_request_ctx(req);
        struct virtio_crypto_request *vc_req = &vc_sym_req->base;
        struct virtio_crypto *vcrypto = ctx->vcrypto;
        /* Use the first data virtqueue as default */
        struct data_queue *data_vq = &vcrypto->data_vq[0];

        if (!req->cryptlen)
                return 0;
        if (req->cryptlen % AES_BLOCK_SIZE)
                return -EINVAL;

        vc_req->dataq = data_vq;
        vc_req->alg_cb = virtio_crypto_dataq_sym_callback;
        vc_sym_req->encrypt = false;

        return crypto_transfer_skcipher_request_to_engine(data_vq->engine, req);
}

static int virtio_crypto_skcipher_init(struct crypto_skcipher *tfm)
{
        crypto_skcipher_set_reqsize(tfm, sizeof(struct virtio_crypto_sym_request));

        return 0;
}

static void virtio_crypto_skcipher_exit(struct crypto_skcipher *tfm)
{
        struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);

        if (!ctx->vcrypto)
                return;

        virtio_crypto_alg_skcipher_close_session(ctx, 1);
        virtio_crypto_alg_skcipher_close_session(ctx, 0);
        virtcrypto_dev_put(ctx->vcrypto);
        ctx->vcrypto = NULL;
}

int virtio_crypto_skcipher_crypt_req(
        struct crypto_engine *engine, void *vreq)
{
        struct skcipher_request *req = container_of(vreq, struct skcipher_request, base);
        struct virtio_crypto_sym_request *vc_sym_req =
                                skcipher_request_ctx(req);
        struct virtio_crypto_request *vc_req = &vc_sym_req->base;
        struct data_queue *data_vq = vc_req->dataq;
        int ret;

        ret = __virtio_crypto_skcipher_do_req(vc_sym_req, req, data_vq);
        if (ret < 0)
                return ret;

        return 0;
}

static void virtio_crypto_skcipher_finalize_req(
        struct virtio_crypto_sym_request *vc_sym_req,
        struct skcipher_request *req,
        int err)
{
        if (vc_sym_req->encrypt)
                scatterwalk_map_and_copy(req->iv, req->dst,
                                         req->cryptlen - AES_BLOCK_SIZE,
                                         AES_BLOCK_SIZE, 0);
        kfree_sensitive(vc_sym_req->iv);
        virtcrypto_clear_request(&vc_sym_req->base);

        crypto_finalize_skcipher_request(vc_sym_req->base.dataq->engine,
                                           req, err);
}

static struct virtio_crypto_algo virtio_crypto_algs[] = { {
        .algonum = VIRTIO_CRYPTO_CIPHER_AES_CBC,
        .service = VIRTIO_CRYPTO_SERVICE_CIPHER,
        .algo.base = {
                .base.cra_name          = "cbc(aes)",
                .base.cra_driver_name   = "virtio_crypto_aes_cbc",
                .base.cra_priority      = 150,
                .base.cra_flags         = CRYPTO_ALG_ASYNC |
                                          CRYPTO_ALG_ALLOCATES_MEMORY,
                .base.cra_blocksize     = AES_BLOCK_SIZE,
                .base.cra_ctxsize       = sizeof(struct virtio_crypto_skcipher_ctx),
                .base.cra_module        = THIS_MODULE,
                .init                   = virtio_crypto_skcipher_init,
                .exit                   = virtio_crypto_skcipher_exit,
                .setkey                 = virtio_crypto_skcipher_setkey,
                .decrypt                = virtio_crypto_skcipher_decrypt,
                .encrypt                = virtio_crypto_skcipher_encrypt,
                .min_keysize            = AES_MIN_KEY_SIZE,
                .max_keysize            = AES_MAX_KEY_SIZE,
                .ivsize                 = AES_BLOCK_SIZE,
        },
        .algo.op = {
                .do_one_request = virtio_crypto_skcipher_crypt_req,
        },
} };

int virtio_crypto_skcipher_algs_register(struct virtio_crypto *vcrypto)
{
        int ret = 0;
        int i = 0;

        mutex_lock(&algs_lock);

        for (i = 0; i < ARRAY_SIZE(virtio_crypto_algs); i++) {

                uint32_t service = virtio_crypto_algs[i].service;
                uint32_t algonum = virtio_crypto_algs[i].algonum;

                if (!virtcrypto_algo_is_supported(vcrypto, service, algonum))
                        continue;

                if (virtio_crypto_algs[i].active_devs == 0) {
                        ret = crypto_engine_register_skcipher(&virtio_crypto_algs[i].algo);
                        if (ret)
                                goto unlock;
                }

                virtio_crypto_algs[i].active_devs++;
                dev_info(&vcrypto->vdev->dev, "Registered algo %s\n",
                         virtio_crypto_algs[i].algo.base.base.cra_name);
        }

unlock:
        mutex_unlock(&algs_lock);
        return ret;
}

void virtio_crypto_skcipher_algs_unregister(struct virtio_crypto *vcrypto)
{
        int i = 0;

        mutex_lock(&algs_lock);

        for (i = 0; i < ARRAY_SIZE(virtio_crypto_algs); i++) {

                uint32_t service = virtio_crypto_algs[i].service;
                uint32_t algonum = virtio_crypto_algs[i].algonum;

                if (virtio_crypto_algs[i].active_devs == 0 ||
                    !virtcrypto_algo_is_supported(vcrypto, service, algonum))
                        continue;

                if (virtio_crypto_algs[i].active_devs == 1)
                        crypto_engine_unregister_skcipher(&virtio_crypto_algs[i].algo);

                virtio_crypto_algs[i].active_devs--;
        }

        mutex_unlock(&algs_lock);
}