// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Cryptographic API.
 *
 * HMAC: Keyed-Hashing for Message Authentication (RFC2104).
 *
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
 *
 * The HMAC implementation is derived from USAGI.
 * Copyright (c) 2002 Kazunori Miyazawa <miyazawa@linux-ipv6.org> / USAGI
 */

#include <crypto/hmac.h>
#include <crypto/internal/hash.h>
#include <linux/err.h>
#include <linux/fips.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/string.h>

struct hmac_ctx {
        struct crypto_shash *hash;
        /* Contains 'u8 ipad[statesize];', then 'u8 opad[statesize];' */
        u8 pads[];
};

struct ahash_hmac_ctx {
        struct crypto_ahash *hash;
        /* Contains 'u8 ipad[statesize];', then 'u8 opad[statesize];' */
        u8 pads[];
};

static int hmac_setkey(struct crypto_shash *parent,
                       const u8 *inkey, unsigned int keylen)
{
        int bs = crypto_shash_blocksize(parent);
        int ds = crypto_shash_digestsize(parent);
        int ss = crypto_shash_statesize(parent);
        struct hmac_ctx *tctx = crypto_shash_ctx(parent);
        struct crypto_shash *hash = tctx->hash;
        u8 *ipad = &tctx->pads[0];
        u8 *opad = &tctx->pads[ss];
        SHASH_DESC_ON_STACK(shash, hash);
        int err, i;

        if (fips_enabled && (keylen < 112 / 8))
                return -EINVAL;

        shash->tfm = hash;

        if (keylen > bs) {
                int err;

                err = crypto_shash_digest(shash, inkey, keylen, ipad);
                if (err)
                        return err;

                keylen = ds;
        } else
                memcpy(ipad, inkey, keylen);

        memset(ipad + keylen, 0, bs - keylen);
        memcpy(opad, ipad, bs);

        for (i = 0; i < bs; i++) {
                ipad[i] ^= HMAC_IPAD_VALUE;
                opad[i] ^= HMAC_OPAD_VALUE;
        }

        err = crypto_shash_init(shash) ?:
              crypto_shash_update(shash, ipad, bs) ?:
              crypto_shash_export(shash, ipad) ?:
              crypto_shash_init(shash) ?:
              crypto_shash_update(shash, opad, bs) ?:
              crypto_shash_export(shash, opad);
        shash_desc_zero(shash);
        return err;
}

static int hmac_export(struct shash_desc *pdesc, void *out)
{
        struct shash_desc *desc = shash_desc_ctx(pdesc);

        return crypto_shash_export(desc, out);
}

static int hmac_import(struct shash_desc *pdesc, const void *in)
{
        struct shash_desc *desc = shash_desc_ctx(pdesc);
        const struct hmac_ctx *tctx = crypto_shash_ctx(pdesc->tfm);

        desc->tfm = tctx->hash;

        return crypto_shash_import(desc, in);
}

static int hmac_export_core(struct shash_desc *pdesc, void *out)
{
        struct shash_desc *desc = shash_desc_ctx(pdesc);

        return crypto_shash_export_core(desc, out);
}

static int hmac_import_core(struct shash_desc *pdesc, const void *in)
{
        const struct hmac_ctx *tctx = crypto_shash_ctx(pdesc->tfm);
        struct shash_desc *desc = shash_desc_ctx(pdesc);

        desc->tfm = tctx->hash;
        return crypto_shash_import_core(desc, in);
}

static int hmac_init(struct shash_desc *pdesc)
{
        const struct hmac_ctx *tctx = crypto_shash_ctx(pdesc->tfm);

        return hmac_import(pdesc, &tctx->pads[0]);
}

static int hmac_update(struct shash_desc *pdesc,
                       const u8 *data, unsigned int nbytes)
{
        struct shash_desc *desc = shash_desc_ctx(pdesc);

        return crypto_shash_update(desc, data, nbytes);
}

static int hmac_finup(struct shash_desc *pdesc, const u8 *data,
                      unsigned int nbytes, u8 *out)
{

        struct crypto_shash *parent = pdesc->tfm;
        int ds = crypto_shash_digestsize(parent);
        int ss = crypto_shash_statesize(parent);
        const struct hmac_ctx *tctx = crypto_shash_ctx(parent);
        const u8 *opad = &tctx->pads[ss];
        struct shash_desc *desc = shash_desc_ctx(pdesc);

        return crypto_shash_finup(desc, data, nbytes, out) ?:
               crypto_shash_import(desc, opad) ?:
               crypto_shash_finup(desc, out, ds, out);
}

static int hmac_init_tfm(struct crypto_shash *parent)
{
        struct crypto_shash *hash;
        struct shash_instance *inst = shash_alg_instance(parent);
        struct crypto_shash_spawn *spawn = shash_instance_ctx(inst);
        struct hmac_ctx *tctx = crypto_shash_ctx(parent);

        hash = crypto_spawn_shash(spawn);
        if (IS_ERR(hash))
                return PTR_ERR(hash);

        tctx->hash = hash;
        return 0;
}

static int hmac_clone_tfm(struct crypto_shash *dst, struct crypto_shash *src)
{
        struct hmac_ctx *sctx = crypto_shash_ctx(src);
        struct hmac_ctx *dctx = crypto_shash_ctx(dst);
        struct crypto_shash *hash;

        hash = crypto_clone_shash(sctx->hash);
        if (IS_ERR(hash))
                return PTR_ERR(hash);

        dctx->hash = hash;
        return 0;
}

static void hmac_exit_tfm(struct crypto_shash *parent)
{
        struct hmac_ctx *tctx = crypto_shash_ctx(parent);

        crypto_free_shash(tctx->hash);
}

static int __hmac_create_shash(struct crypto_template *tmpl,
                               struct rtattr **tb, u32 mask)
{
        struct shash_instance *inst;
        struct crypto_shash_spawn *spawn;
        struct crypto_alg *alg;
        struct shash_alg *salg;
        int err;
        int ds;
        int ss;

        inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
        if (!inst)
                return -ENOMEM;
        spawn = shash_instance_ctx(inst);

        mask |= CRYPTO_AHASH_ALG_NO_EXPORT_CORE;
        err = crypto_grab_shash(spawn, shash_crypto_instance(inst),
                                crypto_attr_alg_name(tb[1]), 0, mask);
        if (err)
                goto err_free_inst;
        salg = crypto_spawn_shash_alg(spawn);
        alg = &salg->base;

        /* The underlying hash algorithm must not require a key */
        err = -EINVAL;
        if (crypto_shash_alg_needs_key(salg))
                goto err_free_inst;

        ds = salg->digestsize;
        ss = salg->statesize;
        if (ds > alg->cra_blocksize ||
            ss < alg->cra_blocksize)
                goto err_free_inst;

        err = crypto_inst_setname(shash_crypto_instance(inst), "hmac",
                                  "hmac-shash", alg);
        if (err)
                goto err_free_inst;

        inst->alg.base.cra_priority = alg->cra_priority;
        inst->alg.base.cra_blocksize = alg->cra_blocksize;
        inst->alg.base.cra_ctxsize = sizeof(struct hmac_ctx) + (ss * 2);

        inst->alg.digestsize = ds;
        inst->alg.statesize = ss;
        inst->alg.descsize = sizeof(struct shash_desc) + salg->descsize;
        inst->alg.init = hmac_init;
        inst->alg.update = hmac_update;
        inst->alg.finup = hmac_finup;
        inst->alg.export = hmac_export;
        inst->alg.import = hmac_import;
        inst->alg.export_core = hmac_export_core;
        inst->alg.import_core = hmac_import_core;
        inst->alg.setkey = hmac_setkey;
        inst->alg.init_tfm = hmac_init_tfm;
        inst->alg.clone_tfm = hmac_clone_tfm;
        inst->alg.exit_tfm = hmac_exit_tfm;

        inst->free = shash_free_singlespawn_instance;

        err = shash_register_instance(tmpl, inst);
        if (err) {
err_free_inst:
                shash_free_singlespawn_instance(inst);
        }
        return err;
}

static int hmac_setkey_ahash(struct crypto_ahash *parent,
                             const u8 *inkey, unsigned int keylen)
{
        struct ahash_hmac_ctx *tctx = crypto_ahash_ctx(parent);
        struct crypto_ahash *fb = crypto_ahash_fb(tctx->hash);
        int ds = crypto_ahash_digestsize(parent);
        int bs = crypto_ahash_blocksize(parent);
        int ss = crypto_ahash_statesize(parent);
        HASH_REQUEST_ON_STACK(req, fb);
        u8 *opad = &tctx->pads[ss];
        u8 *ipad = &tctx->pads[0];
        int err, i;

        if (fips_enabled && (keylen < 112 / 8))
                return -EINVAL;

        ahash_request_set_callback(req, 0, NULL, NULL);

        if (keylen > bs) {
                ahash_request_set_virt(req, inkey, ipad, keylen);
                err = crypto_ahash_digest(req);
                if (err)
                        goto out_zero_req;

                keylen = ds;
        } else
                memcpy(ipad, inkey, keylen);

        memset(ipad + keylen, 0, bs - keylen);
        memcpy(opad, ipad, bs);

        for (i = 0; i < bs; i++) {
                ipad[i] ^= HMAC_IPAD_VALUE;
                opad[i] ^= HMAC_OPAD_VALUE;
        }

        ahash_request_set_virt(req, ipad, NULL, bs);
        err = crypto_ahash_init(req) ?:
              crypto_ahash_update(req) ?:
              crypto_ahash_export(req, ipad);

        ahash_request_set_virt(req, opad, NULL, bs);
        err = err ?:
              crypto_ahash_init(req) ?:
              crypto_ahash_update(req) ?:
              crypto_ahash_export(req, opad);

out_zero_req:
        HASH_REQUEST_ZERO(req);
        return err;
}

static int hmac_export_ahash(struct ahash_request *preq, void *out)
{
        return crypto_ahash_export(ahash_request_ctx(preq), out);
}

static int hmac_import_ahash(struct ahash_request *preq, const void *in)
{
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(preq);
        struct ahash_hmac_ctx *tctx = crypto_ahash_ctx(tfm);
        struct ahash_request *req = ahash_request_ctx(preq);

        ahash_request_set_tfm(req, tctx->hash);
        return crypto_ahash_import(req, in);
}

static int hmac_export_core_ahash(struct ahash_request *preq, void *out)
{
        return crypto_ahash_export_core(ahash_request_ctx(preq), out);
}

static int hmac_import_core_ahash(struct ahash_request *preq, const void *in)
{
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(preq);
        struct ahash_hmac_ctx *tctx = crypto_ahash_ctx(tfm);
        struct ahash_request *req = ahash_request_ctx(preq);

        ahash_request_set_tfm(req, tctx->hash);
        return crypto_ahash_import_core(req, in);
}

static int hmac_init_ahash(struct ahash_request *preq)
{
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(preq);
        struct ahash_hmac_ctx *tctx = crypto_ahash_ctx(tfm);

        return hmac_import_ahash(preq, &tctx->pads[0]);
}

static int hmac_update_ahash(struct ahash_request *preq)
{
        struct ahash_request *req = ahash_request_ctx(preq);

        ahash_request_set_callback(req, ahash_request_flags(preq),
                                   preq->base.complete, preq->base.data);
        if (ahash_request_isvirt(preq))
                ahash_request_set_virt(req, preq->svirt, NULL, preq->nbytes);
        else
                ahash_request_set_crypt(req, preq->src, NULL, preq->nbytes);
        return crypto_ahash_update(req);
}

static int hmac_finup_finish(struct ahash_request *preq, unsigned int mask)
{
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(preq);
        struct ahash_request *req = ahash_request_ctx(preq);
        struct ahash_hmac_ctx *tctx = crypto_ahash_ctx(tfm);
        int ds = crypto_ahash_digestsize(tfm);
        int ss = crypto_ahash_statesize(tfm);
        const u8 *opad = &tctx->pads[ss];

        ahash_request_set_callback(req, ahash_request_flags(preq) & ~mask,
                                   preq->base.complete, preq->base.data);
        ahash_request_set_virt(req, preq->result, preq->result, ds);
        return crypto_ahash_import(req, opad) ?:
               crypto_ahash_finup(req);

}

static void hmac_finup_done(void *data, int err)
{
        struct ahash_request *preq = data;

        if (err)
                goto out;

        err = hmac_finup_finish(preq, CRYPTO_TFM_REQ_MAY_SLEEP);
        if (err == -EINPROGRESS || err == -EBUSY)
                return;

out:
        ahash_request_complete(preq, err);
}

static int hmac_finup_ahash(struct ahash_request *preq)
{
        struct ahash_request *req = ahash_request_ctx(preq);

        ahash_request_set_callback(req, ahash_request_flags(preq),
                                   hmac_finup_done, preq);
        if (ahash_request_isvirt(preq))
                ahash_request_set_virt(req, preq->svirt, preq->result,
                                       preq->nbytes);
        else
                ahash_request_set_crypt(req, preq->src, preq->result,
                                        preq->nbytes);
        return crypto_ahash_finup(req) ?:
               hmac_finup_finish(preq, 0);
}

static int hmac_digest_ahash(struct ahash_request *preq)
{
        return hmac_init_ahash(preq) ?:
               hmac_finup_ahash(preq);
}

static int hmac_init_ahash_tfm(struct crypto_ahash *parent)
{
        struct ahash_instance *inst = ahash_alg_instance(parent);
        struct ahash_hmac_ctx *tctx = crypto_ahash_ctx(parent);
        struct crypto_ahash *hash;

        hash = crypto_spawn_ahash(ahash_instance_ctx(inst));
        if (IS_ERR(hash))
                return PTR_ERR(hash);

        if (crypto_ahash_reqsize(parent) < sizeof(struct ahash_request) +
                                           crypto_ahash_reqsize(hash))
                return -EINVAL;

        tctx->hash = hash;
        return 0;
}

static int hmac_clone_ahash_tfm(struct crypto_ahash *dst,
                                struct crypto_ahash *src)
{
        struct ahash_hmac_ctx *sctx = crypto_ahash_ctx(src);
        struct ahash_hmac_ctx *dctx = crypto_ahash_ctx(dst);
        struct crypto_ahash *hash;

        hash = crypto_clone_ahash(sctx->hash);
        if (IS_ERR(hash))
                return PTR_ERR(hash);

        dctx->hash = hash;
        return 0;
}

static void hmac_exit_ahash_tfm(struct crypto_ahash *parent)
{
        struct ahash_hmac_ctx *tctx = crypto_ahash_ctx(parent);

        crypto_free_ahash(tctx->hash);
}

static int hmac_create_ahash(struct crypto_template *tmpl, struct rtattr **tb,
                             u32 mask)
{
        struct crypto_ahash_spawn *spawn;
        struct ahash_instance *inst;
        struct crypto_alg *alg;
        struct hash_alg_common *halg;
        int ds, ss, err;

        inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
        if (!inst)
                return -ENOMEM;
        spawn = ahash_instance_ctx(inst);

        mask |= CRYPTO_AHASH_ALG_NO_EXPORT_CORE;
        err = crypto_grab_ahash(spawn, ahash_crypto_instance(inst),
                                crypto_attr_alg_name(tb[1]), 0, mask);
        if (err)
                goto err_free_inst;
        halg = crypto_spawn_ahash_alg(spawn);
        alg = &halg->base;

        /* The underlying hash algorithm must not require a key */
        err = -EINVAL;
        if (crypto_hash_alg_needs_key(halg))
                goto err_free_inst;

        ds = halg->digestsize;
        ss = halg->statesize;
        if (ds > alg->cra_blocksize || ss < alg->cra_blocksize)
                goto err_free_inst;

        err = crypto_inst_setname(ahash_crypto_instance(inst), tmpl->name, alg);
        if (err)
                goto err_free_inst;

        inst->alg.halg.base.cra_flags = alg->cra_flags &
                                        CRYPTO_ALG_INHERITED_FLAGS;
        inst->alg.halg.base.cra_flags |= CRYPTO_ALG_REQ_VIRT;
        inst->alg.halg.base.cra_priority = alg->cra_priority + 100;
        inst->alg.halg.base.cra_blocksize = alg->cra_blocksize;
        inst->alg.halg.base.cra_ctxsize = sizeof(struct ahash_hmac_ctx) +
                                          (ss * 2);
        inst->alg.halg.base.cra_reqsize = sizeof(struct ahash_request) +
                                          alg->cra_reqsize;

        inst->alg.halg.digestsize = ds;
        inst->alg.halg.statesize = ss;
        inst->alg.init = hmac_init_ahash;
        inst->alg.update = hmac_update_ahash;
        inst->alg.finup = hmac_finup_ahash;
        inst->alg.digest = hmac_digest_ahash;
        inst->alg.export = hmac_export_ahash;
        inst->alg.import = hmac_import_ahash;
        inst->alg.export_core = hmac_export_core_ahash;
        inst->alg.import_core = hmac_import_core_ahash;
        inst->alg.setkey = hmac_setkey_ahash;
        inst->alg.init_tfm = hmac_init_ahash_tfm;
        inst->alg.clone_tfm = hmac_clone_ahash_tfm;
        inst->alg.exit_tfm = hmac_exit_ahash_tfm;

        inst->free = ahash_free_singlespawn_instance;

        err = ahash_register_instance(tmpl, inst);
        if (err) {
err_free_inst:
                ahash_free_singlespawn_instance(inst);
        }
        return err;
}

static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
{
        struct crypto_attr_type *algt;
        u32 mask;

        algt = crypto_get_attr_type(tb);
        if (IS_ERR(algt))
                return PTR_ERR(algt);

        mask = crypto_algt_inherited_mask(algt);

        if (!((algt->type ^ CRYPTO_ALG_TYPE_AHASH) &
              algt->mask & CRYPTO_ALG_TYPE_MASK))
                return hmac_create_ahash(tmpl, tb, mask);

        if ((algt->type ^ CRYPTO_ALG_TYPE_SHASH) &
            algt->mask & CRYPTO_ALG_TYPE_MASK)
                return -EINVAL;

        return __hmac_create_shash(tmpl, tb, mask);
}

static int hmac_create_shash(struct crypto_template *tmpl, struct rtattr **tb)
{
        u32 mask;
        int err;

        err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH, &mask);
        if (err)
                return err == -EINVAL ? -ENOENT : err;

        return __hmac_create_shash(tmpl, tb, mask);
}

static struct crypto_template hmac_tmpls[] = {
        {
                .name = "hmac",
                .create = hmac_create,
                .module = THIS_MODULE,
        },
        {
                .name = "hmac-shash",
                .create = hmac_create_shash,
                .module = THIS_MODULE,
        },
};

static int __init hmac_module_init(void)
{
        return crypto_register_templates(hmac_tmpls, ARRAY_SIZE(hmac_tmpls));
}

static void __exit hmac_module_exit(void)
{
        crypto_unregister_templates(hmac_tmpls, ARRAY_SIZE(hmac_tmpls));
}

module_init(hmac_module_init);
module_exit(hmac_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("HMAC hash algorithm");
MODULE_ALIAS_CRYPTO("hmac");