path: root/providers/implementations/kdfs/x942kdf.c

/*
 * Copyright 2019-2020 The OpenSSL Project Authors. All Rights Reserved.
 * Copyright (c) 2019, Oracle and/or its affiliates.  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
 */

#include "e_os.h"
#include <openssl/core_names.h>
#include <openssl/core_dispatch.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/params.h>
#include "internal/packet.h"
#include "internal/der.h"
#include "prov/provider_ctx.h"
#include "prov/providercommonerr.h"
#include "prov/implementations.h"
#include "prov/provider_util.h"
#include "prov/der_wrap.h"

#define X942KDF_MAX_INLEN (1 << 30)

static OSSL_FUNC_kdf_newctx_fn x942kdf_new;
static OSSL_FUNC_kdf_freectx_fn x942kdf_free;
static OSSL_FUNC_kdf_reset_fn x942kdf_reset;
static OSSL_FUNC_kdf_derive_fn x942kdf_derive;
static OSSL_FUNC_kdf_settable_ctx_params_fn x942kdf_settable_ctx_params;
static OSSL_FUNC_kdf_set_ctx_params_fn x942kdf_set_ctx_params;
static OSSL_FUNC_kdf_gettable_ctx_params_fn x942kdf_gettable_ctx_params;
static OSSL_FUNC_kdf_get_ctx_params_fn x942kdf_get_ctx_params;

typedef struct {
    void *provctx;
    PROV_DIGEST digest;
    unsigned char *secret;
    size_t secret_len;
    unsigned char *ukm;
    size_t ukm_len;
    size_t dkm_len;
    const unsigned char *cek_oid;
    size_t cek_oid_len;
} KDF_X942;

/*
 * A table of allowed wrapping algorithms, oids and the associated output
 * lengths.
 * NOTE: RC2wrap and camellia128_wrap have been removed as there are no
 * corresponding ciphers for these operations.
 */
static const struct {
    const char *name;
    const unsigned char *oid;
    size_t oid_len;
    size_t keklen; /* size in bytes */
} kek_algs[] = {
    { "AES-128-WRAP", der_oid_id_aes128_wrap, DER_OID_SZ_id_aes128_wrap, 16 },
    { "AES-192-WRAP", der_oid_id_aes192_wrap, DER_OID_SZ_id_aes192_wrap, 24 },
    { "AES-256-WRAP", der_oid_id_aes256_wrap, DER_OID_SZ_id_aes256_wrap, 32 },
#ifndef FIPS_MODULE
    { "DES3-WRAP", der_oid_id_alg_CMS3DESwrap, DER_OID_SZ_id_alg_CMS3DESwrap,
      24 },
#endif
};

static int find_alg_id(OPENSSL_CTX *libctx, const char *algname, size_t *id)
{
    int ret = 1;
    size_t i;
    EVP_CIPHER *cipher;

    cipher = EVP_CIPHER_fetch(libctx, algname, NULL);
    if (cipher != NULL) {
        for (i = 0; i < OSSL_NELEM(kek_algs); i++) {
            if (EVP_CIPHER_is_a(cipher, kek_algs[i].name)) {
                *id = i;
                goto end;
            }
        }
    }
    ret = 0;
    ERR_raise(ERR_LIB_PROV, PROV_R_UNSUPPORTED_CEK_ALG);
end:
    EVP_CIPHER_free(cipher);
    return ret;
}

static int DER_w_keyinfo(WPACKET *pkt,
                         const unsigned char *der_oid, size_t der_oidlen,
                         unsigned char **pcounter)
{
    return DER_w_begin_sequence(pkt, -1)
           /* Store the initial value of 1 into the counter */
           && DER_w_octet_string_uint32(pkt, -1, 1)
           /* Remember where we stored the counter in the buffer */
           && (pcounter == NULL
               || (*pcounter = WPACKET_get_curr(pkt)) != NULL)
           && DER_w_precompiled(pkt, -1, der_oid, der_oidlen)
           && DER_w_end_sequence(pkt, -1);
}

static int der_encode_sharedinfo(WPACKET *pkt, unsigned char *buf, size_t buflen,
                                 const unsigned char *der_oid, size_t der_oidlen,
                                 const unsigned char *ukm, size_t ukmlen,
                                 uint32_t keylen_bits, unsigned char **pcounter)
{
    return (buf != NULL ? WPACKET_init_der(pkt, buf, buflen) :
                          WPACKET_init_null_der(pkt))
           && DER_w_begin_sequence(pkt, -1)
           && DER_w_octet_string_uint32(pkt, 2, keylen_bits)
           && (ukm == NULL || DER_w_octet_string(pkt, 0, ukm, ukmlen))
           && DER_w_keyinfo(pkt, der_oid, der_oidlen, pcounter)
           && DER_w_end_sequence(pkt, -1)
           && WPACKET_finish(pkt);
}

/*
 * Encode the other info structure.
 *
 *  RFC2631 Section 2.1.2 Contains the following definition for otherinfo
 *
 *  OtherInfo ::= SEQUENCE {
 *      keyInfo KeySpecificInfo,
 *      partyAInfo [0] OCTET STRING OPTIONAL,
 *      suppPubInfo [2] OCTET STRING
 *  }
 *  Note suppPubInfo is the key length (in bits) (stored into 4 bytes)
 *
 *
 *  KeySpecificInfo ::= SEQUENCE {
 *      algorithm OBJECT IDENTIFIER,
 *      counter OCTET STRING SIZE (4..4)
 *  }
 *
 * |keylen| is the length (in bytes) of the generated KEK. It is stored into
 * suppPubInfo (in bits).
 * |cek_oid| The oid of the key wrapping algorithm.
 * |cek_oidlen| The length (in bytes) of the key wrapping algorithm oid,
 * |ukm| is the optional user keying material that is stored into partyAInfo. It
 * can be NULL.
 * |ukmlen| is the user keying material length (in bytes).
 * |der| is the returned encoded data. It must be freed by the caller.
 * |der_len| is the returned size of the encoded data.
 * |out_ctr| returns a pointer to the counter data which is embedded inside the
 * encoded data. This allows the counter bytes to be updated without re-encoding.
 *
 * Returns: 1 if successfully encoded, or 0 otherwise.
 * Assumptions: |der|, |der_len| & |out_ctr| are not NULL.
 */
static int x942_encode_otherinfo(size_t keylen,
                                 const unsigned char *cek_oid, size_t cek_oidlen,
                                 const unsigned char *ukm, size_t ukmlen,
                                 unsigned char **der, size_t *der_len,
                                 unsigned char **out_ctr)
{
    int ret = 0;
    unsigned char *pcounter = NULL, *der_buf = NULL;
    size_t der_buflen = 0;
    WPACKET pkt;
    uint32_t keylen_bits;

    /* keylenbits must fit into 4 bytes */
    if (keylen > 0xFFFFFF)
        goto err;
    keylen_bits = 8 * keylen;

    /* Calculate the size of the buffer */
    if (!der_encode_sharedinfo(&pkt, NULL, 0, cek_oid, cek_oidlen, ukm, ukmlen,
                               keylen_bits, NULL)
        || !WPACKET_get_total_written(&pkt, &der_buflen))
        goto err;
    WPACKET_cleanup(&pkt);
    /* Alloc the buffer */
    der_buf = OPENSSL_zalloc(der_buflen);
    if (der_buf == NULL)
        goto err;
    /* Encode into the buffer */
    if (!der_encode_sharedinfo(&pkt, der_buf, der_buflen, cek_oid, cek_oidlen,
                               ukm, ukmlen, keylen_bits, &pcounter))
        goto err;
    /*
     * Since we allocated the exact size required, the buffer should point to the
     * start of the alllocated buffer at this point.
     */
    if (WPACKET_get_curr(&pkt) != der_buf)
        goto err;

    /*
     * The data for the DER encoded octet string of a 32 bit counter = 1
     * should be 04 04 00 00 00 01
     * So just check the header is correct and skip over it.
     * This counter will be incremented in the kdf update loop.
     */
    if (pcounter == NULL
        || pcounter[0] != 0x04
        || pcounter[1] != 0x04)
        goto err;
    *out_ctr = (pcounter + 2);
    *der = der_buf;
    *der_len = der_buflen;
    ret = 1;
err:
    WPACKET_cleanup(&pkt);
    return ret;
}

static int x942kdf_hash_kdm(const EVP_MD *kdf_md,
                            const unsigned char *z, size_t z_len,
                            const unsigned char *other, size_t other_len,
                            unsigned char *ctr,
                            unsigned char *derived_key, size_t derived_key_len)
{
    int ret = 0, hlen;
    size_t counter, out_len, len = derived_key_len;
    unsigned char mac[EVP_MAX_MD_SIZE];
    unsigned char *out = derived_key;
    EVP_MD_CTX *ctx = NULL, *ctx_init = NULL;

    if (z_len > X942KDF_MAX_INLEN || other_len > X942KDF_MAX_INLEN
            || derived_key_len > X942KDF_MAX_INLEN
            || derived_key_len == 0) {
        ERR_raise(ERR_LIB_PROV, PROV_R_BAD_LENGTH);
        return 0;
    }

    hlen =