/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */ /* * Copyright (C) 1998 by the FundsXpress, INC. * * All rights reserved. * * Export of this software from the United States of America may require * a specific license from the United States Government. It is the * responsibility of any person or organization contemplating export to * obtain such a license before exporting. * * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and * distribute this software and its documentation for any purpose and * without fee is hereby granted, provided that the above copyright * notice appear in all copies and that both that copyright notice and * this permission notice appear in supporting documentation, and that * the name of FundsXpress. not be used in advertising or publicity pertaining * to distribution of the software without specific, written prior * permission. FundsXpress makes no representations about the suitability of * this software for any purpose. It is provided "as is" without express * or implied warranty. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ #include "crypto_int.h" static const unsigned char kerberos[] = "kerberos"; #define kerberos_len (sizeof(kerberos)-1) krb5_error_code krb5int_dk_string_to_key(const struct krb5_keytypes *ktp, const krb5_data *string, const krb5_data *salt, const krb5_data *parms, krb5_keyblock *keyblock) { krb5_error_code ret; size_t keybytes, keylength, concatlen; unsigned char *concat = NULL, *foldstring = NULL, *foldkeydata = NULL; krb5_data indata; krb5_keyblock foldkeyblock; krb5_key foldkey = NULL; /* keyblock->length is checked by krb5int_derive_key. */ keybytes = ktp->enc->keybytes; keylength = ktp->enc->keylength; concatlen = string->length + salt->length; concat = k5alloc(concatlen, &ret); if (ret != 0) goto cleanup; foldstring = k5alloc(keybytes, &ret); if (ret != 0) goto cleanup; foldkeydata = k5alloc(keylength, &ret); if (ret != 0) goto cleanup; /* construct input string ( = string + salt), fold it, make_key it */ if (string->length > 0) memcpy(concat, string->data, string->length); if (salt->length > 0) memcpy(concat + string->length, salt->data, salt->length); krb5int_nfold(concatlen*8, concat, keybytes*8, foldstring); indata.length = keybytes; indata.data = (char *) foldstring; foldkeyblock.length = keylength; foldkeyblock.contents = foldkeydata; foldkeyblock.enctype = ktp->etype; ret = ktp->rand2key(&indata, &foldkeyblock); if (ret != 0) goto cleanup; ret = krb5_k_create_key(NULL, &foldkeyblock, &foldkey); if (ret != 0) goto cleanup; /* now derive the key from this one */ indata.length = kerberos_len; indata.data = (char *) kerberos; ret = krb5int_derive_keyblock(ktp->enc, NULL, foldkey, keyblock, &indata, DERIVE_RFC3961); if (ret != 0) memset(keyblock->contents, 0, keyblock->length); cleanup: zapfree(concat, concatlen); zapfree(foldstring, keybytes); zapfree(foldkeydata, keylength); krb5_k_free_key(NULL, foldkey); return ret; } #define MAX_ITERATION_COUNT 0x1000000L krb5_boolean k5_allow_weak_pbkdf2iter = FALSE; static krb5_error_code pbkdf2_string_to_key(const struct krb5_keytypes *ktp, const krb5_data *string, const krb5_data *salt, const krb5_data *pepper, const krb5_data *params, krb5_keyblock *key, enum deriv_alg deriv_alg, unsigned long def_iter_count) { const struct krb5_hash_provider *hash; unsigned long iter_count; krb5_data out; static const krb5_data usage = { KV5M_DATA, 8, "kerberos" }; krb5_key tempkey = NULL; krb5_error_code err; krb5_data sandp = empty_data(); if (params) { unsigned char *p = (unsigned char *) params->data; if (params->length != 4) return KRB5_ERR_BAD_S2K_PARAMS; iter_count = load_32_be(p); /* Zero means 2^32, which is way above what we will accept. Also don't * accept values less than the default, unless we're running tests. */ if (iter_count == 0 || (!k5_allow_weak_pbkdf2iter && iter_count < def_iter_count)) return KRB5_ERR_BAD_S2K_PARAMS; } else iter_count = def_iter_count; /* This is not a protocol specification constraint; this is an implementation limit, which should eventually be controlled by a config file. */ if (iter_count >= MAX_ITERATION_COUNT) return KRB5_ERR_BAD_S2K_PARAMS; /* Use the output keyblock contents for temporary space. */ out.data = (char *) key->contents; out.length = key->length; if (out.length != 16 && out.length != 32) return KRB5_CRYPTO_INTERNAL; if (pepper != NULL) { err = alloc_data(&sandp, pepper->length + 1 + salt->length); if (err) return err; if (pepper->length > 0) memcpy(sandp.data, pepper->data, pepper->length); sandp.data[pepper->length] = '\0'; if (salt->length > 0) memcpy(&sandp.data[pepper->length + 1], salt->data, salt->length); salt = &sandp; } hash = (ktp->hash != NULL) ? ktp->hash : &krb5int_hash_sha1; err = krb5int_pbkdf2_hmac(hash, &out, iter_count, string, salt); if (err) goto cleanup; err = krb5_k_create_key (NULL, key, &tempkey); if (err) goto cleanup; err = krb5int_derive_keyblock(ktp->enc, ktp->hash, tempkey, key, &usage, deriv_alg); cleanup: if (sandp.data) free(sandp.data); if (err) memset (out.data, 0, out.length); krb5_k_free_key (NULL, tempkey); return err; } krb5_error_code krb5int_aes_string_to_key(const struct krb5_keytypes *ktp, const krb5_data *string, const krb5_data *salt, const krb5_data *params, krb5_keyblock *key) { return pbkdf2_string_to_key(ktp, string, salt, NULL, params, key, DERIVE_RFC3961, 4096); } krb5_error_code krb5int_camellia_string_to_key(const struct krb5_keytypes *ktp, const krb5_data *string, const krb5_data *salt, const krb5_data *params, krb5_keyblock *key) { krb5_data pepper = string2data(ktp->name); return pbkdf2_string_to_key(ktp, string, salt, &pepper, params, key, DERIVE_SP800_108_CMAC, 32768); } krb5_error_code krb5int_aes2_string_to_key(const struct krb5_keytypes *ktp, const krb5_data *string, const krb5_data *salt, const krb5_data *params, krb5_keyblock *key) { krb5_data pepper = string2data(ktp->name); return pbkdf2_string_to_key(ktp, string, salt, &pepper, params, key, DERIVE_SP800_108_HMAC, 32768); }