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NetBSD/crypto/dist/heimdal/appl/kx/krb5.c

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/*
* Copyright (c) 1995 - 1999 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "kx.h"
RCSID("$Id: krb5.c,v 1.1.1.2 2000/08/02 19:58:31 assar Exp $");
#ifdef KRB5
struct krb5_kx_context {
krb5_context context;
krb5_keyblock *keyblock;
krb5_crypto crypto;
krb5_principal client;
};
typedef struct krb5_kx_context krb5_kx_context;
/*
* Destroy the krb5 context in `c'.
*/
static void
krb5_destroy (kx_context *c)
{
krb5_kx_context *kc = (krb5_kx_context *)c->data;
if (kc->keyblock)
krb5_free_keyblock (kc->context, kc->keyblock);
if (kc->crypto)
krb5_crypto_destroy (kc->context, kc->crypto);
if (kc->client)
krb5_free_principal (kc->context, kc->client);
if (kc->context)
krb5_free_context (kc->context);
free (kc);
}
/*
* Read the authentication information from `s' and return 0 if
* succesful, else -1.
*/
static int
krb5_authenticate (kx_context *kc, int s)
{
krb5_kx_context *c = (krb5_kx_context *)kc->data;
krb5_context context = c->context;
krb5_auth_context auth_context = NULL;
krb5_error_code ret;
krb5_principal server;
const char *host = kc->host;
ret = krb5_sname_to_principal (context,
host, "host", KRB5_NT_SRV_HST, &server);
if (ret) {
warnx ("krb5_sname_to_principal: %s: %s", host,
krb5_get_err_text(context, ret));
return 1;
}
ret = krb5_sendauth (context,
&auth_context,
&s,
KX_VERSION,
NULL,
server,
AP_OPTS_MUTUAL_REQUIRED,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL);
if (ret) {
warnx ("krb5_sendauth: %s: %s", host,
krb5_get_err_text(context, ret));
return 1;
}
ret = krb5_auth_con_getkey (context, auth_context, &c->keyblock);
if (ret) {
warnx ("krb5_auth_con_getkey: %s: %s", host,
krb5_get_err_text(context, ret));
krb5_auth_con_free (context, auth_context);
return 1;
}
ret = krb5_crypto_init (context, c->keyblock, 0, &c->crypto);
if (ret) {
warnx ("krb5_crypto_init: %s", krb5_get_err_text (context, ret));
krb5_auth_con_free (context, auth_context);
return 1;
}
return 0;
}
/*
* Read an encapsulated krb5 packet from `fd' into `buf' (of size
* `len'). Return the number of bytes read or 0 on EOF or -1 on
* error.
*/
static ssize_t
krb5_read (kx_context *kc,
int fd, void *buf, size_t len)
{
krb5_kx_context *c = (krb5_kx_context *)kc->data;
krb5_context context = c->context;
size_t data_len, outer_len;
krb5_error_code ret;
unsigned char tmp[4];
krb5_data data;
int l;
l = krb5_net_read (context, &fd, tmp, 4);
if (l == 0)
return l;
if (l != 4)
return -1;
data_len = (tmp[0] << 24) | (tmp[1] << 16) | (tmp[2] << 8) | tmp[3];
outer_len = krb5_get_wrapped_length (context, c->crypto, data_len);
if (outer_len > len)
return -1;
if (krb5_net_read (context, &fd, buf, outer_len) != outer_len)
return -1;
ret = krb5_decrypt (context, c->crypto, KRB5_KU_OTHER_ENCRYPTED,
buf, outer_len, &data);
if (ret) {
warnx ("krb5_decrypt: %s", krb5_get_err_text(context, ret));
return -1;
}
if (data_len > data.length) {
krb5_data_free (&data);
return -1;
}
memmove (buf, data.data, data_len);
krb5_data_free (&data);
return data_len;
}
/*
* Write an encapsulated krb5 packet on `fd' with the data in `buf,
* len'. Return len or -1 on error.
*/
static ssize_t
krb5_write(kx_context *kc,
int fd, const void *buf, size_t len)
{
krb5_kx_context *c = (krb5_kx_context *)kc->data;
krb5_context context = c->context;
krb5_data data;
krb5_error_code ret;
unsigned char tmp[4];
size_t outlen;
ret = krb5_encrypt (context, c->crypto, KRB5_KU_OTHER_ENCRYPTED,
(void *)buf, len, &data);
if (ret){
warnx ("krb5_write: %s", krb5_get_err_text (context, ret));
return -1;
}
outlen = data.length;
tmp[0] = (len >> 24) & 0xFF;
tmp[1] = (len >> 16) & 0xFF;
tmp[2] = (len >> 8) & 0xFF;
tmp[3] = (len >> 0) & 0xFF;
if (krb5_net_write (context, &fd, tmp, 4) != 4 ||
krb5_net_write (context, &fd, data.data, outlen) != outlen) {
krb5_data_free (&data);
return -1;
}
krb5_data_free (&data);
return len;
}
/*
* Copy from the unix socket `from_fd' encrypting to `to_fd'.
* Return 0, -1 or len.
*/
static int
copy_out (kx_context *kc, int from_fd, int to_fd)
{
char buf[32768];
ssize_t len;
len = read (from_fd, buf, sizeof(buf));
if (len == 0)
return 0;
if (len < 0) {
warn ("read");
return len;
}
return krb5_write (kc, to_fd, buf, len);
}
/*
* Copy from the socket `from_fd' decrypting to `to_fd'.
* Return 0, -1 or len.
*/
static int
copy_in (kx_context *kc, int from_fd, int to_fd)
{
krb5_kx_context *c = (krb5_kx_context *)kc->data;
char buf[33000]; /* XXX */
ssize_t len;
len = krb5_read (kc, from_fd, buf, sizeof(buf));
if (len == 0)
return 0;
if (len < 0) {
warn ("krb5_read");
return len;
}
return krb5_net_write (c->context, &to_fd, buf, len);
}
/*
* Copy data between `fd1' and `fd2', encrypting in one direction and
* decrypting in the other.
*/
static int
krb5_copy_encrypted (kx_context *kc, int fd1, int fd2)
{
for (;;) {
fd_set fdset;
int ret;
FD_ZERO(&fdset);
FD_SET(fd1, &fdset);
FD_SET(fd2, &fdset);
ret = select (max(fd1, fd2)+1, &fdset, NULL, NULL, NULL);
if (ret < 0 && errno != EINTR) {
warn ("select");
return 1;
}
if (FD_ISSET(fd1, &fdset)) {
ret = copy_out (kc, fd1, fd2);
if (ret <= 0)
return ret;
}
if (FD_ISSET(fd2, &fdset)) {
ret = copy_in (kc, fd2, fd1);
if (ret <= 0)
return ret;
}
}
}
/*
* Return 0 if the user authenticated on `kc' is allowed to login as
* `user'.
*/
static int
krb5_userok (kx_context *kc, char *user)
{
krb5_kx_context *c = (krb5_kx_context *)kc->data;
krb5_context context = c->context;
krb5_error_code ret;
char *tmp;
ret = krb5_unparse_name (context, c->client, &tmp);
if (ret)
krb5_err (context, 1, ret, "krb5_unparse_name");
kc->user = tmp;
return !krb5_kuserok (context, c->client, user);
}
/*
* Create an instance of an krb5 context.
*/
void
krb5_make_context (kx_context *kc)
{
krb5_kx_context *c;
kc->authenticate = krb5_authenticate;
kc->userok = krb5_userok;
kc->read = krb5_read;
kc->write = krb5_write;
kc->copy_encrypted = krb5_copy_encrypted;
kc->destroy = krb5_destroy;
kc->user = NULL;
kc->data = malloc(sizeof(krb5_kx_context));
if (kc->data == NULL)
err (1, "malloc");
memset (kc->data, 0, sizeof(krb5_kx_context));
c = (krb5_kx_context *)kc->data;
krb5_init_context (&c->context);
}
/*
* Receive authentication information on `sock' (first four bytes
* in `buf').
*/
int
recv_v5_auth (kx_context *kc, int sock, u_char *buf)
{
u_int32_t len;
krb5_error_code ret;
krb5_kx_context *c;
krb5_context context;
krb5_principal server;
krb5_auth_context auth_context = NULL;
krb5_ticket *ticket;
if (memcmp (buf, "\x00\x00\x00\x13", 4) != 0)
return 1;
len = (buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | (buf[3]);
if (net_read(sock, buf, len) != len) {
syslog (LOG_ERR, "read: %m");
exit (1);
}
if (len != sizeof(KRB5_SENDAUTH_VERSION)
|| memcmp (buf, KRB5_SENDAUTH_VERSION, len) != 0) {
syslog (LOG_ERR, "bad sendauth version: %.8s", buf);
exit (1);
}
krb5_make_context (kc);
c = (krb5_kx_context *)kc->data;
context = c->context;
ret = krb5_sock_to_principal (context, sock, "host",
KRB5_NT_SRV_HST, &server);
if (ret) {
syslog (LOG_ERR, "krb5_sock_to_principal: %s",
krb5_get_err_text (context, ret));
exit (1);
}
ret = krb5_recvauth (context,
&auth_context,
&sock,
KX_VERSION,
server,
KRB5_RECVAUTH_IGNORE_VERSION,
NULL,
&ticket);
krb5_free_principal (context, server);
if (ret) {
syslog (LOG_ERR, "krb5_sock_to_principal: %s",
krb5_get_err_text (context, ret));
exit (1);
}
ret = krb5_auth_con_getkey (context, auth_context, &c->keyblock);
if (ret) {
syslog (LOG_ERR, "krb5_auth_con_getkey: %s",
krb5_get_err_text (context, ret));
exit (1);
}
ret = krb5_crypto_init (context, c->keyblock, 0, &c->crypto);
if (ret) {
syslog (LOG_ERR, "krb5_crypto_init: %s",
krb5_get_err_text (context, ret));
exit (1);
}
c->client = ticket->client;
ticket->client = NULL;
krb5_free_ticket (context, ticket);
return 0;
}
#endif /* KRB5 */
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