/*
 * Copyright 2022-2025 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */
/* clang-format off */

/* clang-format on */

#include <stdlib.h>
#include <string.h>
#include <openssl/crypto.h>
#include <openssl/err.h>
#include <openssl/kdf.h>
#include <openssl/proverr.h>
#include <openssl/core_names.h>
#include "internal/common.h"
#include "prov/providercommon.h"
#include "prov/implementations.h"
#include "prov/hmac_drbg.h"
#include "prov/provider_ctx.h"

static OSSL_FUNC_kdf_newctx_fn hmac_drbg_kdf_new;
static OSSL_FUNC_kdf_dupctx_fn hmac_drbg_kdf_dup;
static OSSL_FUNC_kdf_freectx_fn hmac_drbg_kdf_free;
static OSSL_FUNC_kdf_reset_fn hmac_drbg_kdf_reset;
static OSSL_FUNC_kdf_derive_fn hmac_drbg_kdf_derive;
static OSSL_FUNC_kdf_settable_ctx_params_fn hmac_drbg_kdf_settable_ctx_params;
static OSSL_FUNC_kdf_set_ctx_params_fn hmac_drbg_kdf_set_ctx_params;
static OSSL_FUNC_kdf_gettable_ctx_params_fn hmac_drbg_kdf_gettable_ctx_params;
static OSSL_FUNC_kdf_get_ctx_params_fn hmac_drbg_kdf_get_ctx_params;

typedef struct {
    PROV_DRBG_HMAC base;
    void *provctx;
    unsigned char *entropy, *nonce;
    size_t entropylen, noncelen;
    int init;
} KDF_HMAC_DRBG;

static void *hmac_drbg_kdf_new(void *provctx)
{
    KDF_HMAC_DRBG *ctx;

    if (!ossl_prov_is_running())
        return NULL;

    ctx = OPENSSL_zalloc(sizeof(*ctx));
    if (ctx == NULL) {
        ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
        return NULL;
    }
    ctx->provctx = provctx;
    return ctx;
}

static void hmac_drbg_kdf_reset(void *vctx)
{
    KDF_HMAC_DRBG *ctx = (KDF_HMAC_DRBG *)vctx;
    PROV_DRBG_HMAC *drbg = &ctx->base;
    void *provctx = ctx->provctx;

    EVP_MAC_CTX_free(drbg->ctx);
    ossl_prov_digest_reset(&drbg->digest);
    OPENSSL_clear_free(ctx->entropy, ctx->entropylen);
    OPENSSL_clear_free(ctx->nonce, ctx->noncelen);
    OPENSSL_cleanse(ctx, sizeof(*ctx));
    ctx->provctx = provctx;
}

static void hmac_drbg_kdf_free(void *vctx)
{
    KDF_HMAC_DRBG *ctx = (KDF_HMAC_DRBG *)vctx;

    if (ctx != NULL) {
        hmac_drbg_kdf_reset(ctx);
        OPENSSL_free(ctx);
    }
}

static int ossl_drbg_hmac_dup(PROV_DRBG_HMAC *dst, const PROV_DRBG_HMAC *src)
{
    if (src->ctx != NULL) {
        dst->ctx = EVP_MAC_CTX_dup(src->ctx);
        if (dst->ctx == NULL)
            return 0;
    }
    if (!ossl_prov_digest_copy(&dst->digest, &src->digest))
        return 0;
    memcpy(dst->K, src->K, sizeof(dst->K));
    memcpy(dst->V, src->V, sizeof(dst->V));
    dst->blocklen = src->blocklen;
    return 1;
}

static void *hmac_drbg_kdf_dup(void *vctx)
{
    const KDF_HMAC_DRBG *src = (const KDF_HMAC_DRBG *)vctx;
    KDF_HMAC_DRBG *dst;

    dst = hmac_drbg_kdf_new(src->provctx);
    if (dst != NULL) {
        if (!ossl_drbg_hmac_dup(&dst->base, &src->base)
            || !ossl_prov_memdup(src->entropy, src->entropylen,
                &dst->entropy, &dst->entropylen)
            || !ossl_prov_memdup(src->nonce, src->noncelen,
                &dst->nonce, &dst->noncelen))
            goto err;
        dst->init = src->init;
    }
    return dst;

err:
    hmac_drbg_kdf_free(dst);
    return NULL;
}

static int hmac_drbg_kdf_derive(void *vctx, unsigned char *out, size_t outlen,
    const OSSL_PARAM params[])
{
    KDF_HMAC_DRBG *ctx = (KDF_HMAC_DRBG *)vctx;
    PROV_DRBG_HMAC *drbg = &ctx->base;

    if (!ossl_prov_is_running()
        || !hmac_drbg_kdf_set_ctx_params(vctx, params))
        return 0;
    if (!ctx->init) {
        if (ctx->entropy == NULL
            || ctx->entropylen == 0
            || ctx->nonce == NULL
            || ctx->noncelen == 0
            || !ossl_drbg_hmac_init(drbg, ctx->entropy, ctx->entropylen,
                ctx->nonce, ctx->noncelen, NULL, 0))
            return 0;
        ctx->init = 1;
    }

    return ossl_drbg_hmac_generate(drbg, out, outlen, NULL, 0);
}

/* clang-format off */
/* Machine generated by util/perl/OpenSSL/paramnames.pm */
#ifndef hmac_drbg_kdf_get_ctx_params_list
static const OSSL_PARAM hmac_drbg_kdf_get_ctx_params_list[] = {
    OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_MAC, NULL, 0),
    OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
    OSSL_PARAM_END
};
#endif

#ifndef hmac_drbg_kdf_get_ctx_params_st
struct hmac_drbg_kdf_get_ctx_params_st {
    OSSL_PARAM *digest;
    OSSL_PARAM *mac;
};
#endif

#ifndef hmac_drbg_kdf_get_ctx_params_decoder
static int hmac_drbg_kdf_get_ctx_params_decoder
    (const OSSL_PARAM *p, struct hmac_drbg_kdf_get_ctx_params_st *r)
{
    const char *s;

    memset(r, 0, sizeof(*r));
    if (p != NULL)
        for (; (s = p->key) != NULL; p++)
            switch(s[0]) {
            default:
                break;
            case 'd':
                if (ossl_likely(strcmp("igest", s + 1) == 0)) {
                    /* OSSL_KDF_PARAM_DIGEST */
                    if (ossl_unlikely(r->digest != NULL)) {
                        ERR_raise_data(ERR_LIB_PROV, PROV_R_REPEATED_PARAMETER,
                                       "param %s is repeated", s);
                        return 0;
                    }
                    r->digest = (OSSL_PARAM *)p;
                }
                break;
            case 'm':
                if (ossl_likely(strcmp("ac", s + 1) == 0)) {
                    /* OSSL_KDF_PARAM_MAC */
                    if (ossl_unlikely(r->mac != NULL)) {
                        ERR_raise_data(ERR_LIB_PROV, PROV_R_REPEATED_PARAMETER,
                                       "param %s is repeated", s);
                        return 0;
                    }
                    r->mac = (OSSL_PARAM *)p;
                }
            }
    return 1;
}
#endif
/* End of machine generated */
/* clang-format on */

static int hmac_drbg_kdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
{
    KDF_HMAC_DRBG *hmac = (KDF_HMAC_DRBG *)vctx;
    PROV_DRBG_HMAC *drbg = &hmac->base;
    const char *name;
    const EVP_MD *md;
    struct hmac_drbg_kdf_get_ctx_params_st p;

    if (hmac == NULL || !hmac_drbg_kdf_get_ctx_params_decoder(params, &p))
        return 0;

    if (p.mac != NULL) {
        if (drbg->ctx == NULL)
            return 0;
        name = EVP_MAC_get0_name(EVP_MAC_CTX_get0_mac(drbg->ctx));
        if (!OSSL_PARAM_set_utf8_string(p.mac, name))
            return 0;
    }

    if (p.digest != NULL) {
        md = ossl_prov_digest_md(&drbg->digest);
        if (md == NULL
            || !OSSL_PARAM_set_utf8_string(p.digest, EVP_MD_get0_name(md)))
            return 0;
    }
    return 1;
}

static const OSSL_PARAM *hmac_drbg_kdf_gettable_ctx_params(
    ossl_unused void *vctx, ossl_unused void *p_ctx)
{
    return hmac_drbg_kdf_get_ctx_params_list;
}

/* clang-format off */
/* Machine generated by util/perl/OpenSSL/paramnames.pm */
#ifndef hmac_drbg_kdf_set_ctx_params_list
static const OSSL_PARAM hmac_drbg_kdf_set_ctx_params_list[] = {
    OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
    OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
    OSSL_PARAM_octet_string(OSSL_KDF_PARAM_HMACDRBG_ENTROPY, NULL, 0),
    OSSL_PARAM_octet_string(OSSL_KDF_PARAM_HMACDRBG_NONCE, NULL, 0),
    OSSL_PARAM_END
};
#endif

#ifndef hmac_drbg_kdf_set_ctx_params_st
struct hmac_drbg_kdf_set_ctx_params_st {
    OSSL_PARAM *digest;
    OSSL_PARAM *engine;
    OSSL_PARAM *ent;
    OSSL_PARAM *nonce;
    OSSL_PARAM *propq;
};
#endif

#ifndef hmac_drbg_kdf_set_ctx_params_decoder
static int hmac_drbg_kdf_set_ctx_params_decoder
    (const OSSL_PARAM *p, struct hmac_drbg_kdf_set_ctx_params_st *r)
{
    const char *s;

    memset(r, 0, sizeof(*r));
    if (p != NULL)
        for (; (s = p->key) != NULL; p++)
            switch(s[0]) {
            default:
                break;
            case 'd':
                if (ossl_likely(strcmp("igest", s + 1) == 0)) {
                    /* OSSL_KDF_PARAM_DIGEST */
                    if (ossl_unlikely(r->digest != NULL)) {
                        ERR_raise_data(ERR_LIB_PROV, PROV_R_REPEATED_PARAMETER,
                                       "param %s is repeated", s);
                        return 0;
                    }
                    r->digest = (OSSL_PARAM *)p;
                }
                break;
            case 'e':
                switch(s[1]) {
                default:
                    break;
                case 'n':
                    switch(s[2]) {
                    default:
                        break;
                    case 'g':
                        if (ossl_likely(strcmp("ine", s + 3) == 0)) {
                            /* OSSL_ALG_PARAM_ENGINE */
                            if (ossl_unlikely(r->engine != NULL)) {
                                ERR_raise_data(ERR_LIB_PROV, PROV_R_REPEATED_PARAMETER,
                                               "param %s is repeated", s);
                                return 0;
                            }
                            r->engine = (OSSL_PARAM *)p;
                        }
                        break;
                    case 't':
                        if (ossl_likely(strcmp("ropy", s + 3) == 0)) {
                            /* OSSL_KDF_PARAM_HMACDRBG_ENTROPY */
                            if (ossl_unlikely(r->ent != NULL)) {
                                ERR_raise_data(ERR_LIB_PROV, PROV_R_REPEATED_PARAMETER,
                                               "param %s is repeated", s);
                                return 0;
                            }
                            r->ent = (OSSL_PARAM *)p;
                        }
                    }
                }
                break;
            case 'n':
                if (ossl_likely(strcmp("once", s + 1) == 0)) {
                    /* OSSL_KDF_PARAM_HMACDRBG_NONCE */
                    if (ossl_unlikely(r->nonce != NULL)) {
                        ERR_raise_data(ERR_LIB_PROV, PROV_R_REPEATED_PARAMETER,
                                       "param %s is repeated", s);
                        return 0;
                    }
                    r->nonce = (OSSL_PARAM *)p;
                }
                break;
            case 'p':
                if (ossl_likely(strcmp("roperties", s + 1) == 0)) {
                    /* OSSL_KDF_PARAM_PROPERTIES */
                    if (ossl_unlikely(r->propq != NULL)) {
                        ERR_raise_data(ERR_LIB_PROV, PROV_R_REPEATED_PARAMETER,
                                       "param %s is repeated", s);
                        return 0;
                    }
                    r->propq = (OSSL_PARAM *)p;
                }
            }
    return 1;
}
#endif
/* End of machine generated */
/* clang-format on */

static int hmac_drbg_kdf_set_ctx_params(void *vctx,
    const OSSL_PARAM params[])
{
    KDF_HMAC_DRBG *hmac = (KDF_HMAC_DRBG *)vctx;
    PROV_DRBG_HMAC *drbg;
    OSSL_LIB_CTX *libctx;
    const EVP_MD *md;
    struct hmac_drbg_kdf_set_ctx_params_st p;
    void *ptr = NULL;
    size_t size = 0;
    int md_size;

    if (hmac == NULL || !hmac_drbg_kdf_set_ctx_params_decoder(params, &p))
        return 0;

    drbg = &hmac->base;
    libctx = PROV_LIBCTX_OF(hmac->provctx);

    if (p.ent != NULL) {
        if (!OSSL_PARAM_get_octet_string(p.ent, &ptr, 0, &size))
            return 0;
        OPENSSL_free(hmac->entropy);
        hmac->entropy = ptr;
        hmac->entropylen = size;
        hmac->init = 0;
        ptr = NULL;
    }

    if (p.nonce != NULL) {
        if (!OSSL_PARAM_get_octet_string(p.nonce, &ptr, 0, &size))
            return 0;
        OPENSSL_free(hmac->nonce);
        hmac->nonce = ptr;
        hmac->noncelen = size;
        hmac->init = 0;
    }

    if (p.digest != NULL) {
        if (!ossl_prov_digest_load(&drbg->digest, p.digest,
                p.propq, p.engine, libctx))
            return 0;

        /* Confirm digest is allowed. Allow all digests that are not XOF */
        md = ossl_prov_digest_md(&drbg->digest);
        if (md != NULL) {
            if (EVP_MD_xof(md)) {
                ERR_raise(ERR_LIB_PROV, PROV_R_XOF_DIGESTS_NOT_ALLOWED);
                return 0;
            }
            md_size = EVP_MD_get_size(md);
            if (md_size <= 0)
                return 0;
            drbg->blocklen = (size_t)md_size;
        }
        if (!ossl_prov_macctx_load(&drbg->ctx, NULL, NULL, p.digest, p.propq,
                p.engine, "HMAC", NULL, NULL, libctx))
            return 0;
    }
    return 1;
}

static const OSSL_PARAM *hmac_drbg_kdf_settable_ctx_params(
    ossl_unused void *vctx, ossl_unused void *p_ctx)
{
    return hmac_drbg_kdf_set_ctx_params_list;
}

const OSSL_DISPATCH ossl_kdf_hmac_drbg_functions[] = {
    { OSSL_FUNC_KDF_NEWCTX, (void (*)(void))hmac_drbg_kdf_new },
    { OSSL_FUNC_KDF_FREECTX, (void (*)(void))hmac_drbg_kdf_free },
    { OSSL_FUNC_KDF_DUPCTX, (void (*)(void))hmac_drbg_kdf_dup },
    { OSSL_FUNC_KDF_RESET, (void (*)(void))hmac_drbg_kdf_reset },
    { OSSL_FUNC_KDF_DERIVE, (void (*)(void))hmac_drbg_kdf_derive },
    { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
        (void (*)(void))hmac_drbg_kdf_settable_ctx_params },
    { OSSL_FUNC_KDF_SET_CTX_PARAMS,
        (void (*)(void))hmac_drbg_kdf_set_ctx_params },
    { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
        (void (*)(void))hmac_drbg_kdf_gettable_ctx_params },
    { OSSL_FUNC_KDF_GET_CTX_PARAMS,
        (void (*)(void))hmac_drbg_kdf_get_ctx_params },
    OSSL_DISPATCH_END
};
