/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/*

 * TLS 1.3 Protocol

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "keyhi.h"

#include "pk11func.h"

#include "secitem.h"

#include "ssl.h"

#include "sslt.h"

#include "sslerr.h"

#include "sslimpl.h"

/* This table contains the mapping between TLS hash identifiers and the

 * PKCS#11 identifiers */

static const struct {

    SSLHashType hash;

    CK_MECHANISM_TYPE pkcs11Mech;

    unsigned int hashSize;

} kTlsHkdfInfo[] = {

    { ssl_hash_none, 0, 0 },

    { ssl_hash_md5, 0, 0 },

    { ssl_hash_sha1, 0, 0 },

    { ssl_hash_sha224, 0 },

    { ssl_hash_sha256, CKM_SHA256, 32 },

    { ssl_hash_sha384, CKM_SHA384, 48 },

    { ssl_hash_sha512, CKM_SHA512, 64 }

};

SECStatus

tls13_HkdfExtract(PK11SymKey *ikm1, PK11SymKey *ikm2, SSLHashType baseHash,

                  PK11SymKey **prkp)

{

    CK_HKDF_PARAMS params;

    SECItem paramsi;

    PK11SymKey *prk;

    static const PRUint8 zeroKeyBuf[HASH_LENGTH_MAX];

    SECItem zeroKeyItem = { siBuffer, CONST_CAST(PRUint8, zeroKeyBuf), kTlsHkdfInfo[baseHash].hashSize };

    PK11SlotInfo *slot = NULL;

    PK11SymKey *newIkm2 = NULL;

    PK11SymKey *newIkm1 = NULL;

    SECStatus rv;

    params.bExtract = CK_TRUE;

    params.bExpand = CK_FALSE;

    params.prfHashMechanism = kTlsHkdfInfo[baseHash].pkcs11Mech;

    params.pInfo = NULL;

    params.ulInfoLen = 0UL;

    params.pSalt = NULL;

    params.ulSaltLen = 0UL;

    params.hSaltKey = CK_INVALID_HANDLE;

    if (!ikm1) {

        /* PKCS #11 v3.0 has and explict NULL value, which equates to

         * a sequence of zeros equal in length to the HMAC. */

        params.ulSaltType = CKF_HKDF_SALT_NULL;

    } else {

        /* PKCS #11 v3.0 can take the salt as a key handle */

        params.hSaltKey = PK11_GetSymKeyHandle(ikm1);

        params.ulSaltType = CKF_HKDF_SALT_KEY;

        /* if we have both keys, make sure they are in the same slot */

        if (ikm2) {

            rv = PK11_SymKeysToSameSlot(CKM_HKDF_DERIVE,

                                        CKA_DERIVE, CKA_DERIVE,

                                        ikm2, ikm1, &newIkm2, &newIkm1);

            if (rv != SECSuccess) {

                SECItem *salt;

                /* couldn't move the keys, try extracting the salt */

                rv = PK11_ExtractKeyValue(ikm1);

                if (rv != SECSuccess)

                    return rv;

                salt = PK11_GetKeyData(ikm1);

                if (!salt)

                    return SECFailure;

                PORT_Assert(salt->len > 0);

                /* Set up for Salt as Data instead of Salt as key */

                params.pSalt = salt->data;

                params.ulSaltLen = salt->len;

                params.ulSaltType = CKF_HKDF_SALT_DATA;

            }

            /* use the new keys */

            if (newIkm1) {

                /* we've moved the key, get the handle for the new key */

                params.hSaltKey = PK11_GetSymKeyHandle(newIkm1);

                /* we don't use ikm1 after this, so don't bother setting it */

            }

            if (newIkm2) {

                /* new ikm2 key, use the new key */

                ikm2 = newIkm2;

            }

        }

    }

    paramsi.data = (unsigned char *)&params;

    paramsi.len = sizeof(params);

    PORT_Assert(kTlsHkdfInfo[baseHash].pkcs11Mech);

    PORT_Assert(kTlsHkdfInfo[baseHash].hashSize);

    PORT_Assert(kTlsHkdfInfo[baseHash].hash == baseHash);

    /* A zero ikm2 is a key of hash-length 0s. */

    if (!ikm2) {

        /* if we have ikm1, put the zero key in the same slot */

        slot = ikm1 ? PK11_GetSlotFromKey(ikm1) : PK11_GetBestSlot(CKM_HKDF_DERIVE, NULL);

        if (!slot) {

            return SECFailure;

        }

        newIkm2 = PK11_ImportDataKey(slot, CKM_HKDF_DERIVE, PK11_OriginUnwrap,

                                     CKA_DERIVE, &zeroKeyItem, NULL);

        if (!newIkm2) {

            return SECFailure;

        }

        ikm2 = newIkm2;

    }

    PORT_Assert(ikm2);

    PRINT_BUF(50, (NULL, "HKDF Extract: IKM1/Salt", params.pSalt, params.ulSaltLen));

    PRINT_KEY(50, (NULL, "HKDF Extract: IKM2", ikm2));

    prk = PK11_Derive(ikm2, CKM_HKDF_DERIVE, &paramsi, CKM_HKDF_DERIVE,

                      CKA_DERIVE, 0);

    PK11_FreeSymKey(newIkm2);

    PK11_FreeSymKey(newIkm1);

    if (slot)

        PK11_FreeSlot(slot);

    if (!prk) {

        return SECFailure;

    }

    PRINT_KEY(50, (NULL, "HKDF Extract", prk));

    *prkp = prk;

    return SECSuccess;

}

SECStatus

tls13_HkdfExpandLabelGeneral(CK_MECHANISM_TYPE deriveMech, PK11SymKey *prk,

                             SSLHashType baseHash,

                             const PRUint8 *handshakeHash, unsigned int handshakeHashLen,

                             const char *label, unsigned int labelLen,

                             CK_MECHANISM_TYPE algorithm, unsigned int keySize,

                             SSLProtocolVariant variant, PK11SymKey **keyp)

{

    CK_HKDF_PARAMS params;

    SECItem paramsi = { siBuffer, NULL, 0 };

    /* Size of info array needs to be big enough to hold the maximum Prefix,

     * Label, plus HandshakeHash. If it's ever to small, the code will abort.

     */

    PRUint8 info[256];

    sslBuffer infoBuf = SSL_BUFFER(info);

    PK11SymKey *derived;

    SECStatus rv;

    const char *kLabelPrefixTls = "tls13 ";

    const char *kLabelPrefixDtls = "dtls13";

    const unsigned int kLabelPrefixLen =

        (variant == ssl_variant_stream) ? strlen(kLabelPrefixTls) : strlen(kLabelPrefixDtls);

    const char *kLabelPrefix =

        (variant == ssl_variant_stream) ? kLabelPrefixTls : kLabelPrefixDtls;

    PORT_Assert(prk);

    PORT_Assert(keyp);

    if ((handshakeHashLen > 255) ||

        (handshakeHash == NULL && handshakeHashLen > 0) ||

        (labelLen + kLabelPrefixLen > 255)) {

        PORT_SetError(SEC_ERROR_INVALID_ARGS);

        return SECFailure;

    }

    /*

     *  [draft-ietf-tls-tls13-11] Section 7.1:

     *

     *  HKDF-Expand-Label(Secret, Label, HashValue, Length) =

     *       HKDF-Expand(Secret, HkdfLabel, Length)

     *

     *  Where HkdfLabel is specified as:

     *

     *  struct HkdfLabel {

     *    uint16 length;

     *    opaque label<9..255>;

     *    opaque hash_value<0..255>;

     *  };

     *

     *  Where:

     *  - HkdfLabel.length is Length

     *  - HkdfLabel.hash_value is HashValue.

     *  - HkdfLabel.label is "TLS 1.3, " + Label

     *

     */

    rv = sslBuffer_AppendNumber(&infoBuf, keySize, 2);

    if (rv != SECSuccess) {

        return SECFailure;

    }

    rv = sslBuffer_AppendNumber(&infoBuf, labelLen + kLabelPrefixLen, 1);

    if (rv != SECSuccess) {

        return SECFailure;

    }

    rv = sslBuffer_Append(&infoBuf, kLabelPrefix, kLabelPrefixLen);

    if (rv != SECSuccess) {

        return SECFailure;

    }

    rv = sslBuffer_Append(&infoBuf, label, labelLen);

    if (rv != SECSuccess) {

        return SECFailure;

    }

    rv = sslBuffer_AppendVariable(&infoBuf, handshakeHash, handshakeHashLen, 1);

    if (rv != SECSuccess) {

        return SECFailure;

    }

    params.bExtract = CK_FALSE;

    params.bExpand = CK_TRUE;

    params.prfHashMechanism = kTlsHkdfInfo[baseHash].pkcs11Mech;

    params.pInfo = SSL_BUFFER_BASE(&infoBuf);

    params.ulInfoLen = SSL_BUFFER_LEN(&infoBuf);

    paramsi.data = (unsigned char *)&params;

    paramsi.len = sizeof(params);

    derived = PK11_DeriveWithFlags(prk, deriveMech,

                                   &paramsi, algorithm,

                                   CKA_DERIVE, keySize,

                                   CKF_SIGN | CKF_VERIFY);

    if (!derived) {

        return SECFailure;

    }

    *keyp = derived;

#ifdef TRACE

    if (ssl_trace >= 50) {

        /* Make sure the label is null terminated. */

        char labelStr[100];

        PORT_Memcpy(labelStr, label, labelLen);

        labelStr[labelLen] = 0;

        SSL_TRC(50, ("HKDF Expand: label='tls13 %s',requested length=%d",

                     labelStr, keySize));

    }

    PRINT_KEY(50, (NULL, "PRK", prk));

    PRINT_BUF(50, (NULL, "Hash", handshakeHash, handshakeHashLen));

    PRINT_BUF(50, (NULL, "Info", SSL_BUFFER_BASE(&infoBuf),

                   SSL_BUFFER_LEN(&infoBuf)));

    PRINT_KEY(50, (NULL, "Derived key", derived));

#endif

    return SECSuccess;

}

SECStatus

tls13_HkdfExpandLabel(PK11SymKey *prk, SSLHashType baseHash,

                      const PRUint8 *handshakeHash, unsigned int handshakeHashLen,

                      const char *label, unsigned int labelLen,

                      CK_MECHANISM_TYPE algorithm, unsigned int keySize,

                      SSLProtocolVariant variant, PK11SymKey **keyp)

{

    return tls13_HkdfExpandLabelGeneral(CKM_HKDF_DERIVE, prk, baseHash,

                                        handshakeHash, handshakeHashLen,

                                        label, labelLen, algorithm, keySize,

                                        variant, keyp);

}

SECStatus

tls13_HkdfExpandLabelRaw(PK11SymKey *prk, SSLHashType baseHash,

                         const PRUint8 *handshakeHash, unsigned int handshakeHashLen,

                         const char *label, unsigned int labelLen,

                         SSLProtocolVariant variant, unsigned char *output,

                         unsigned int outputLen)

{

    PK11SymKey *derived = NULL;

    SECItem *rawkey;

    SECStatus rv;

    /* the result is not really a key, it's a data object */

    rv = tls13_HkdfExpandLabelGeneral(CKM_HKDF_DATA, prk, baseHash,

                                      handshakeHash, handshakeHashLen,

                                      label, labelLen, CKM_HKDF_DERIVE, outputLen,

                                      variant, &derived);

    if (rv != SECSuccess || !derived) {

        goto abort;

    }

    rv = PK11_ExtractKeyValue(derived);

    if (rv != SECSuccess) {

        goto abort;

    }

    rawkey = PK11_GetKeyData(derived);

    if (!rawkey) {

        goto abort;

    }

    PORT_Assert(rawkey->len == outputLen);

    memcpy(output, rawkey->data, outputLen);

    PK11_FreeSymKey(derived);

    return SECSuccess;

abort:

    if (derived) {

        PK11_FreeSymKey(derived);

    }

    PORT_SetError(SSL_ERROR_SYM_KEY_CONTEXT_FAILURE);

    return SECFailure;

}