/*
 * Copyright 2007-2017 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the OpenSSL license (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
 */

#include <stdio.h>
#include "internal/cryptlib.h"
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include <openssl/evp.h>
#include "internal/siphash.h"
#include "siphash_local.h"
#include "internal/evp_int.h"

/* SIPHASH pkey context structure */

typedef struct siphash_pkey_ctx_st {
    ASN1_OCTET_STRING ktmp;     /* Temp storage for key */
    SIPHASH ctx;
} SIPHASH_PKEY_CTX;

static int pkey_siphash_init(EVP_PKEY_CTX *ctx)
{
    SIPHASH_PKEY_CTX *pctx;

    pctx = OPENSSL_zalloc(sizeof(*pctx));
    if (pctx == NULL)
        return 0;
    pctx->ktmp.type = V_ASN1_OCTET_STRING;

    EVP_PKEY_CTX_set_data(ctx, pctx);
    EVP_PKEY_CTX_set0_keygen_info(ctx, NULL, 0);
    return 1;
}

static void pkey_siphash_cleanup(EVP_PKEY_CTX *ctx)
{
    SIPHASH_PKEY_CTX *pctx = EVP_PKEY_CTX_get_data(ctx);

    if (pctx != NULL) {
        OPENSSL_clear_free(pctx->ktmp.data, pctx->ktmp.length);
        OPENSSL_clear_free(pctx, sizeof(*pctx));
        EVP_PKEY_CTX_set_data(ctx, NULL);
    }
}

static int pkey_siphash_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src)
{
    SIPHASH_PKEY_CTX *sctx, *dctx;

    /* allocate memory for dst->data and a new SIPHASH_CTX in dst->data->ctx */
    if (!pkey_siphash_init(dst))
        return 0;
    sctx = EVP_PKEY_CTX_get_data(src);
    dctx = EVP_PKEY_CTX_get_data(dst);
    if (ASN1_STRING_get0_data(&sctx->ktmp) != NULL &&
        !ASN1_STRING_copy(&dctx->ktmp, &sctx->ktmp)) {
        /* cleanup and free the SIPHASH_PKEY_CTX in dst->data */
        pkey_siphash_cleanup(dst);
        return 0;
    }
    memcpy(&dctx->ctx, &sctx->ctx, sizeof(SIPHASH));
    return 1;
}

static int pkey_siphash_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
{
    ASN1_OCTET_STRING *key;
    SIPHASH_PKEY_CTX *pctx = EVP_PKEY_CTX_get_data(ctx);

    if (ASN1_STRING_get0_data(&pctx->ktmp) == NULL)
        return 0;
    key = ASN1_OCTET_STRING_dup(&pctx->ktmp);
    if (key == NULL)
        return 0;
    return EVP_PKEY_assign_SIPHASH(pkey, key);
}

static int int_update(EVP_MD_CTX *ctx, const void *data, size_t count)
{
    SIPHASH_PKEY_CTX *pctx = EVP_PKEY_CTX_get_data(EVP_MD_CTX_pkey_ctx(ctx));

    SipHash_Update(&pctx->ctx, data, count);
    return 1;
}

static int siphash_signctx_init(EVP_PKEY_CTX *ctx, EVP_MD_CTX *mctx)
{
    SIPHASH_PKEY_CTX *pctx = EVP_PKEY_CTX_get_data(ctx);
    const unsigned char* key;
    size_t len;
    int hash_size;

    key = EVP_PKEY_get0_siphash(EVP_PKEY_CTX_get0_pkey(ctx), &len);
    if (key == NULL || len != SIPHASH_KEY_SIZE)
        return 0;
    EVP_MD_CTX_set_flags(mctx, EVP_MD_CTX_FLAG_NO_INIT);
    EVP_MD_CTX_set_update_fn(mctx, int_update);
    /* use default rounds (2,4) */
    hash_size = SipHash_hash_size(&pctx->ctx);
    return SipHash_Init(&pctx->ctx, key, hash_size, 0, 0);
}
static int siphash_signctx(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,
                            EVP_MD_CTX *mctx)
{
    SIPHASH_PKEY_CTX *pctx = ctx->data;

    *siglen = SipHash_hash_size(&pctx->ctx);
    if (sig != NULL)
        return SipHash_Final(&pctx->ctx, sig, *siglen);
    return 1;
}

static int pkey_siphash_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
{
    SIPHASH_PKEY_CTX *pctx = EVP_PKEY_CTX_get_data(ctx);
    const unsigned char *key;
    size_t len;
    int hash_size;

    switch (type) {

    case EVP_PKEY_CTRL_MD:
        /* ignore */
        break;

    case EVP_PKEY_CTRL_SET_DIGEST_SIZE:
        if (p1 != SIPHASH_MIN_DIGEST_SIZE &&
            p1 != SIPHASH_MAX_DIGEST_SIZE) {
            return 0;
        }
        /* use default rounds (2,4) */
        return SipHash_Init(&pctx->ctx, ASN1_STRING_get0_data(&pctx->ktmp), p1, 0, 0);

    case EVP_PKEY_CTRL_SET_MAC_KEY:
    case EVP_PKEY_CTRL_DIGESTINIT:
        if (type == EVP_PKEY_CTRL_SET_MAC_KEY) {
            /* user explicitly setting the key */
            key = p2;
            len = p1;
        } else {
            /* user indirectly setting the key via EVP_DigestSignInit */
            key = EVP_PKEY_get0_siphash(EVP_PKEY_CTX_get0_pkey(ctx), &len);
        }
        if (key == NULL || len != SIPHASH_KEY_SIZE ||
            !ASN1_OCTET_STRING_set(&pctx->ktmp, key, len))
            return 0;
        /* use default rounds (2,4) */
        hash_size = SipHash_hash_size(&pctx->ctx);
        return SipHash_Init(&pctx->ctx, ASN1_STRING_get0_data(&pctx->ktmp), hash_size, 0, 0);

    default:
        return -2;

    }
    return 1;
}

static int pkey_siphash_ctrl_str(EVP_PKEY_CTX *ctx,
                                  const char *type, const char *value)
{
    if (value == NULL)
        return 0;
    if (strcmp(type, "key") == 0)
        return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_SET_MAC_KEY, value);
    if (strcmp(type, "hexkey") == 0)
        return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_SET_MAC_KEY, value);
    return -2;
}

const EVP_PKEY_METHOD siphash_pkey_meth = {
    EVP_PKEY_SIPHASH,
    EVP_PKEY_FLAG_SIGCTX_CUSTOM, /* we don't deal with a separate MD */
    pkey_siphash_init,
    pkey_siphash_copy,
    pkey_siphash_cleanup,

    0, 0,

    0,
    pkey_siphash_keygen,

    0, 0,

    0, 0,

    0, 0,

    siphash_signctx_init,
    siphash_signctx,

    0, 0,

    0, 0,

    0, 0,

    0, 0,

    pkey_siphash_ctrl,
    pkey_siphash_ctrl_str
};