diff options
Diffstat (limited to 'src/lib/crypto/krb/keyhash_provider/k5_md5des.c')
| -rw-r--r-- | src/lib/crypto/krb/keyhash_provider/k5_md5des.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/src/lib/crypto/krb/keyhash_provider/k5_md5des.c b/src/lib/crypto/krb/keyhash_provider/k5_md5des.c new file mode 100644 index 0000000..0175c68 --- /dev/null +++ b/src/lib/crypto/krb/keyhash_provider/k5_md5des.c @@ -0,0 +1,191 @@ +/* + * 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 "k5-int.h" +#include "des_int.h" +#include "rsa-md5.h" +#include "keyhash_provider.h" + +#define CONFLENGTH 8 + +/* Force acceptance of krb5-beta5 md5des checksum for now. */ +#define KRB5_MD5DES_BETA5_COMPAT + +/* des-cbc(xorkey, conf | rsa-md5(conf | data)) */ + +/* this could be done in terms of the md5 and des providers, but + that's less efficient, and there's no need for this to be generic */ + +static krb5_error_code +k5_md5des_hash(const krb5_keyblock *key, krb5_keyusage usage, const krb5_data *ivec, + const krb5_data *input, krb5_data *output) +{ + krb5_error_code ret; + krb5_data data; + krb5_MD5_CTX ctx; + unsigned char conf[CONFLENGTH]; + unsigned char xorkey[8]; + unsigned int i; + mit_des_key_schedule schedule; + + if (key->length != 8) + return(KRB5_BAD_KEYSIZE); + if (ivec) + return(KRB5_CRYPTO_INTERNAL); + if (output->length != (CONFLENGTH+RSA_MD5_CKSUM_LENGTH)) + return(KRB5_CRYPTO_INTERNAL); + + /* create the confouder */ + + data.length = CONFLENGTH; + data.data = (char *) conf; + if ((ret = krb5_c_random_make_octets(/* XXX */ 0, &data))) + return(ret); + + /* create and schedule the encryption key */ + + memcpy(xorkey, key->contents, sizeof(xorkey)); + for (i=0; i<sizeof(xorkey); i++) + xorkey[i] ^= 0xf0; + + switch (ret = mit_des_key_sched(xorkey, schedule)) { + case -1: + return(KRB5DES_BAD_KEYPAR); + case -2: + return(KRB5DES_WEAK_KEY); + } + + /* hash the confounder, then the input data */ + + krb5_MD5Init(&ctx); + krb5_MD5Update(&ctx, conf, CONFLENGTH); + krb5_MD5Update(&ctx, (unsigned char *) input->data, + (unsigned int) input->length); + krb5_MD5Final(&ctx); + + /* construct the buffer to be encrypted */ + + memcpy(output->data, conf, CONFLENGTH); + memcpy(output->data+CONFLENGTH, ctx.digest, RSA_MD5_CKSUM_LENGTH); + + /* encrypt it, in place. this has a return value, but it's + always zero. */ + + mit_des_cbc_encrypt((krb5_pointer) output->data, + (krb5_pointer) output->data, output->length, + schedule, (const unsigned char *) mit_des_zeroblock, + 1); + + return(0); +} + +static krb5_error_code +k5_md5des_verify(const krb5_keyblock *key, krb5_keyusage usage, const krb5_data *ivec, + const krb5_data *input, const krb5_data *hash, + krb5_boolean *valid) +{ + krb5_MD5_CTX ctx; + unsigned char plaintext[CONFLENGTH+RSA_MD5_CKSUM_LENGTH]; + unsigned char xorkey[8]; + unsigned int i; + mit_des_key_schedule schedule; + int compathash = 0; + + if (key->length != 8) + return(KRB5_BAD_KEYSIZE); + if (ivec) + return(KRB5_CRYPTO_INTERNAL); + if (hash->length != (CONFLENGTH+RSA_MD5_CKSUM_LENGTH)) { +#ifdef KRB5_MD5DES_BETA5_COMPAT + if (hash->length != RSA_MD5_CKSUM_LENGTH) + return(KRB5_CRYPTO_INTERNAL); + else + compathash = 1; +#else + return(KRB5_CRYPTO_INTERNAL); +#endif + } + + /* create and schedule the encryption key */ + + memcpy(xorkey, key->contents, sizeof(xorkey)); + if (!compathash) { + for (i=0; i<sizeof(xorkey); i++) + xorkey[i] ^= 0xf0; + } + + switch (mit_des_key_sched(xorkey, schedule)) { + case -1: + return(KRB5DES_BAD_KEYPAR); + case -2: + return(KRB5DES_WEAK_KEY); + } + + /* decrypt it. this has a return value, but it's always zero. */ + + if (!compathash) { + mit_des_cbc_encrypt((krb5_pointer) hash->data, + (krb5_pointer) plaintext, hash->length, + schedule, + (const unsigned char *) mit_des_zeroblock, 0); + } else { + mit_des_cbc_encrypt((krb5_pointer) hash->data, + (krb5_pointer) plaintext, hash->length, + schedule, xorkey, 0); + } + + /* hash the confounder, then the input data */ + + krb5_MD5Init(&ctx); + if (!compathash) { + krb5_MD5Update(&ctx, plaintext, CONFLENGTH); + } + krb5_MD5Update(&ctx, (unsigned char *) input->data, + (unsigned) input->length); + krb5_MD5Final(&ctx); + + /* compare the decrypted hash to the computed one */ + + if (!compathash) { + *valid = + (memcmp(plaintext+CONFLENGTH, ctx.digest, RSA_MD5_CKSUM_LENGTH) + == 0); + } else { + *valid = + (memcmp(plaintext, ctx.digest, RSA_MD5_CKSUM_LENGTH) == 0); + } + memset(plaintext, 0, sizeof(plaintext)); + + return(0); +} + +const struct krb5_keyhash_provider krb5int_keyhash_md5des = { + CONFLENGTH+RSA_MD5_CKSUM_LENGTH, + k5_md5des_hash, + k5_md5des_verify, + NULL, + NULL +}; |