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/*
* lib/krb5/krb/rd_priv.c
*
* Copyright 1990,1991 by the Massachusetts Institute of Technology.
* 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 M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
*
* krb5_rd_priv()
*/
#include "k5-int.h"
extern krb5_deltat krb5_clockskew;
#define in_clock_skew(date) (labs((date)-currenttime) < krb5_clockskew)
/*
Parses a KRB_PRIV message from inbuf, placing the confidential user
data in *outbuf.
key specifies the key to be used for decryption of the message.
sender_addr and recv_addr specify the full
addresses (host and port) of the sender and receiver.
outbuf points to allocated storage which the caller should
free when finished.
i_vector is used as an initialization vector for the
encryption, and if non-NULL its contents are replaced with the last
block of the encrypted data upon exit.
Returns system errors, integrity errors.
*/
krb5_error_code INTERFACE
krb5_rd_priv(context, inbuf, key, sender_addr, recv_addr, seq_number,
priv_flags, i_vector, rcache, outbuf)
krb5_context context;
const krb5_data * inbuf;
const krb5_keyblock * key;
const krb5_address * sender_addr;
const krb5_address * recv_addr;
krb5_int32 seq_number;
krb5_int32 priv_flags;
krb5_pointer i_vector;
krb5_rcache rcache;
krb5_data * outbuf;
{
krb5_error_code retval;
krb5_encrypt_block eblock;
krb5_priv *privmsg;
krb5_priv_enc_part *privmsg_enc_part;
krb5_data scratch;
krb5_timestamp currenttime;
if (!krb5_is_krb_priv(inbuf))
return KRB5KRB_AP_ERR_MSG_TYPE;
/* decode private message */
if (retval = decode_krb5_priv(inbuf, &privmsg)) {
return retval;
}
#define cleanup_privmsg() {(void)krb5_xfree(privmsg->enc_part.ciphertext.data); (void)krb5_xfree(privmsg);}
if (!valid_etype(privmsg->enc_part.etype)) {
cleanup_privmsg();
return KRB5_PROG_ETYPE_NOSUPP;
}
/* put together an eblock for this decryption */
krb5_use_cstype(context, &eblock, privmsg->enc_part.etype);
scratch.length = privmsg->enc_part.ciphertext.length;
if (!(scratch.data = malloc(scratch.length))) {
cleanup_privmsg();
return ENOMEM;
}
#define cleanup_scratch() {(void)memset(scratch.data, 0, scratch.length); (void)krb5_xfree(scratch.data);}
/* do any necessary key pre-processing */
if (retval = krb5_process_key(context, &eblock, key)) {
cleanup_privmsg();
cleanup_scratch();
return retval;
}
#define cleanup_prockey() {(void) krb5_finish_key(context, &eblock);}
/* call the decryption routine */
if (retval = krb5_decrypt(context, (krb5_pointer) privmsg->enc_part.ciphertext.data,
(krb5_pointer) scratch.data,
scratch.length, &eblock,
i_vector)) {
cleanup_privmsg();
cleanup_scratch();
cleanup_prockey();
return retval;
}
/* if i_vector is set, fill it in with the last block of the encrypted
input */
/* put last block into the i_vector */
if (i_vector)
memcpy(i_vector,
privmsg->enc_part.ciphertext.data +
(privmsg->enc_part.ciphertext.length -
eblock.crypto_entry->block_length),
eblock.crypto_entry->block_length);
/* private message is now decrypted -- do some cleanup */
cleanup_privmsg();
if (retval = krb5_finish_key(context, &eblock)) {
cleanup_scratch();
return retval;
}
/* now decode the decrypted stuff */
if (retval = decode_krb5_enc_priv_part(&scratch, &privmsg_enc_part)) {
cleanup_scratch();
return retval;
}
cleanup_scratch();
#define cleanup_data() {(void)memset(privmsg_enc_part->user_data.data,0,privmsg_enc_part->user_data.length); (void)krb5_xfree(privmsg_enc_part->user_data.data);}
#define cleanup_mesg() {(void)krb5_xfree(privmsg_enc_part);}
if (!(priv_flags & KRB5_PRIV_NOTIME)) {
krb5_donot_replay replay;
if (retval = krb5_timeofday(context, ¤ttime)) {
cleanup_data();
cleanup_mesg();
return retval;
}
if (!in_clock_skew(privmsg_enc_part->timestamp)) {
cleanup_data();
cleanup_mesg();
return KRB5KRB_AP_ERR_SKEW;
}
if (!rcache) {
/* gotta provide an rcache in this case... */
cleanup_data();
cleanup_mesg();
return KRB5_RC_REQUIRED;
}
if (retval = krb5_gen_replay_name(context, sender_addr, "_priv",
&replay.client)) {
cleanup_data();
cleanup_mesg();
return retval;
}
replay.server = ""; /* XXX */
replay.cusec = privmsg_enc_part->usec;
replay.ctime = privmsg_enc_part->timestamp;
if (retval = krb5_rc_store(context, rcache, &replay)) {
krb5_xfree(replay.client);
cleanup_data();
cleanup_mesg();
return retval;
}
krb5_xfree(replay.client);
}
if (priv_flags & KRB5_PRIV_DOSEQUENCE)
if (privmsg_enc_part->seq_number != seq_number) {
cleanup_data();
cleanup_mesg();
return KRB5KRB_AP_ERR_BADORDER;
}
if (!krb5_address_compare(context, sender_addr, privmsg_enc_part->s_address)) {
cleanup_data();
cleanup_mesg();
return KRB5KRB_AP_ERR_BADADDR;
}
if (privmsg_enc_part->r_address) {
if (recv_addr) {
if (!krb5_address_compare(context, recv_addr,
privmsg_enc_part->r_address)) {
cleanup_data();
cleanup_mesg();
return KRB5KRB_AP_ERR_BADADDR;
}
} else {
krb5_address **our_addrs;
if (retval = krb5_os_localaddr(&our_addrs)) {
cleanup_data();
cleanup_mesg();
return retval;
}
if (!krb5_address_search(context, privmsg_enc_part->r_address, our_addrs)) {
krb5_free_addresses(context, our_addrs);
cleanup_data();
cleanup_mesg();
return KRB5KRB_AP_ERR_BADADDR;
}
krb5_free_addresses(context, our_addrs);
}
}
/* everything is ok - return data to the user */
*outbuf = privmsg_enc_part->user_data;
cleanup_mesg();
return 0;
}
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