422 lines
10 KiB
C
422 lines
10 KiB
C
/*
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* Copyright (c) 1995 - 2000 Kungliga Tekniska Högskolan
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* (Royal Institute of Technology, Stockholm, Sweden).
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include "kx.h"
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RCSID("$Id: krb5.c,v 1.1.1.3 2001/02/11 13:51:16 assar Exp $");
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#ifdef KRB5
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struct krb5_kx_context {
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krb5_context context;
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krb5_keyblock *keyblock;
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krb5_crypto crypto;
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krb5_principal client;
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};
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typedef struct krb5_kx_context krb5_kx_context;
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/*
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* Destroy the krb5 context in `c'.
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*/
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static void
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krb5_destroy (kx_context *c)
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{
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krb5_kx_context *kc = (krb5_kx_context *)c->data;
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if (kc->keyblock)
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krb5_free_keyblock (kc->context, kc->keyblock);
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if (kc->crypto)
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krb5_crypto_destroy (kc->context, kc->crypto);
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if (kc->client)
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krb5_free_principal (kc->context, kc->client);
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if (kc->context)
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krb5_free_context (kc->context);
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free (kc);
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}
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/*
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* Read the authentication information from `s' and return 0 if
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* succesful, else -1.
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*/
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static int
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krb5_authenticate (kx_context *kc, int s)
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{
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krb5_kx_context *c = (krb5_kx_context *)kc->data;
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krb5_context context = c->context;
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krb5_auth_context auth_context = NULL;
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krb5_error_code ret;
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krb5_principal server;
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const char *host = kc->host;
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ret = krb5_sname_to_principal (context,
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host, "host", KRB5_NT_SRV_HST, &server);
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if (ret) {
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warnx ("krb5_sname_to_principal: %s: %s", host,
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krb5_get_err_text(context, ret));
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return 1;
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}
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ret = krb5_sendauth (context,
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&auth_context,
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&s,
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KX_VERSION,
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NULL,
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server,
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AP_OPTS_MUTUAL_REQUIRED,
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NULL,
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NULL,
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NULL,
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NULL,
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NULL,
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NULL);
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if (ret) {
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warnx ("krb5_sendauth: %s: %s", host,
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krb5_get_err_text(context, ret));
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return 1;
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}
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ret = krb5_auth_con_getkey (context, auth_context, &c->keyblock);
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if (ret) {
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warnx ("krb5_auth_con_getkey: %s: %s", host,
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krb5_get_err_text(context, ret));
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krb5_auth_con_free (context, auth_context);
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return 1;
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}
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ret = krb5_crypto_init (context, c->keyblock, 0, &c->crypto);
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if (ret) {
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warnx ("krb5_crypto_init: %s", krb5_get_err_text (context, ret));
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krb5_auth_con_free (context, auth_context);
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return 1;
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}
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return 0;
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}
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/*
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* Read an encapsulated krb5 packet from `fd' into `buf' (of size
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* `len'). Return the number of bytes read or 0 on EOF or -1 on
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* error.
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*/
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static ssize_t
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krb5_read (kx_context *kc,
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int fd, void *buf, size_t len)
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{
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krb5_kx_context *c = (krb5_kx_context *)kc->data;
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krb5_context context = c->context;
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size_t data_len, outer_len;
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krb5_error_code ret;
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unsigned char tmp[4];
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krb5_data data;
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int l;
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l = krb5_net_read (context, &fd, tmp, 4);
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if (l == 0)
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return l;
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if (l != 4)
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return -1;
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data_len = (tmp[0] << 24) | (tmp[1] << 16) | (tmp[2] << 8) | tmp[3];
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outer_len = krb5_get_wrapped_length (context, c->crypto, data_len);
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if (outer_len > len)
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return -1;
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if (krb5_net_read (context, &fd, buf, outer_len) != outer_len)
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return -1;
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ret = krb5_decrypt (context, c->crypto, KRB5_KU_OTHER_ENCRYPTED,
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buf, outer_len, &data);
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if (ret) {
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warnx ("krb5_decrypt: %s", krb5_get_err_text(context, ret));
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return -1;
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}
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if (data_len > data.length) {
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krb5_data_free (&data);
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return -1;
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}
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memmove (buf, data.data, data_len);
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krb5_data_free (&data);
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return data_len;
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}
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/*
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* Write an encapsulated krb5 packet on `fd' with the data in `buf,
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* len'. Return len or -1 on error.
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*/
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static ssize_t
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krb5_write(kx_context *kc,
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int fd, const void *buf, size_t len)
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{
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krb5_kx_context *c = (krb5_kx_context *)kc->data;
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krb5_context context = c->context;
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krb5_data data;
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krb5_error_code ret;
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unsigned char tmp[4];
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size_t outlen;
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ret = krb5_encrypt (context, c->crypto, KRB5_KU_OTHER_ENCRYPTED,
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(void *)buf, len, &data);
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if (ret){
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warnx ("krb5_write: %s", krb5_get_err_text (context, ret));
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return -1;
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}
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outlen = data.length;
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tmp[0] = (len >> 24) & 0xFF;
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tmp[1] = (len >> 16) & 0xFF;
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tmp[2] = (len >> 8) & 0xFF;
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tmp[3] = (len >> 0) & 0xFF;
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if (krb5_net_write (context, &fd, tmp, 4) != 4 ||
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krb5_net_write (context, &fd, data.data, outlen) != outlen) {
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krb5_data_free (&data);
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return -1;
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}
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krb5_data_free (&data);
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return len;
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}
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/*
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* Copy from the unix socket `from_fd' encrypting to `to_fd'.
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* Return 0, -1 or len.
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*/
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static int
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copy_out (kx_context *kc, int from_fd, int to_fd)
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{
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char buf[32768];
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ssize_t len;
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len = read (from_fd, buf, sizeof(buf));
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if (len == 0)
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return 0;
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if (len < 0) {
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warn ("read");
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return len;
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}
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return krb5_write (kc, to_fd, buf, len);
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}
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/*
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* Copy from the socket `from_fd' decrypting to `to_fd'.
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* Return 0, -1 or len.
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*/
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static int
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copy_in (kx_context *kc, int from_fd, int to_fd)
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{
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krb5_kx_context *c = (krb5_kx_context *)kc->data;
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char buf[33000]; /* XXX */
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ssize_t len;
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len = krb5_read (kc, from_fd, buf, sizeof(buf));
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if (len == 0)
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return 0;
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if (len < 0) {
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warn ("krb5_read");
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return len;
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}
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return krb5_net_write (c->context, &to_fd, buf, len);
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}
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/*
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* Copy data between `fd1' and `fd2', encrypting in one direction and
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* decrypting in the other.
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*/
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static int
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krb5_copy_encrypted (kx_context *kc, int fd1, int fd2)
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{
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for (;;) {
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fd_set fdset;
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int ret;
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if (fd1 >= FD_SETSIZE || fd2 >= FD_SETSIZE) {
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warnx ("fd too large");
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return 1;
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}
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FD_ZERO(&fdset);
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FD_SET(fd1, &fdset);
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FD_SET(fd2, &fdset);
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ret = select (max(fd1, fd2)+1, &fdset, NULL, NULL, NULL);
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if (ret < 0 && errno != EINTR) {
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warn ("select");
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return 1;
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}
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if (FD_ISSET(fd1, &fdset)) {
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ret = copy_out (kc, fd1, fd2);
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if (ret <= 0)
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return ret;
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}
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if (FD_ISSET(fd2, &fdset)) {
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ret = copy_in (kc, fd2, fd1);
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if (ret <= 0)
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return ret;
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}
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}
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}
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/*
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* Return 0 if the user authenticated on `kc' is allowed to login as
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* `user'.
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*/
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static int
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krb5_userok (kx_context *kc, char *user)
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{
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krb5_kx_context *c = (krb5_kx_context *)kc->data;
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krb5_context context = c->context;
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krb5_error_code ret;
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char *tmp;
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ret = krb5_unparse_name (context, c->client, &tmp);
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if (ret)
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krb5_err (context, 1, ret, "krb5_unparse_name");
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kc->user = tmp;
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return !krb5_kuserok (context, c->client, user);
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}
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/*
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* Create an instance of an krb5 context.
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*/
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void
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krb5_make_context (kx_context *kc)
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{
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krb5_kx_context *c;
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krb5_error_code ret;
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kc->authenticate = krb5_authenticate;
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kc->userok = krb5_userok;
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kc->read = krb5_read;
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kc->write = krb5_write;
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kc->copy_encrypted = krb5_copy_encrypted;
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kc->destroy = krb5_destroy;
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kc->user = NULL;
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kc->data = malloc(sizeof(krb5_kx_context));
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if (kc->data == NULL)
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err (1, "malloc");
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memset (kc->data, 0, sizeof(krb5_kx_context));
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c = (krb5_kx_context *)kc->data;
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ret = krb5_init_context (&c->context);
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if (ret)
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errx (1, "krb5_init_context failed: %d", ret);
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}
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/*
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* Receive authentication information on `sock' (first four bytes
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* in `buf').
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*/
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int
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recv_v5_auth (kx_context *kc, int sock, u_char *buf)
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{
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u_int32_t len;
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krb5_error_code ret;
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krb5_kx_context *c;
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krb5_context context;
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krb5_principal server;
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krb5_auth_context auth_context = NULL;
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krb5_ticket *ticket;
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if (memcmp (buf, "\x00\x00\x00\x13", 4) != 0)
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return 1;
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len = (buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | (buf[3]);
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if (net_read(sock, buf, len) != len) {
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syslog (LOG_ERR, "read: %m");
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exit (1);
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}
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if (len != sizeof(KRB5_SENDAUTH_VERSION)
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|| memcmp (buf, KRB5_SENDAUTH_VERSION, len) != 0) {
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syslog (LOG_ERR, "bad sendauth version: %.8s", buf);
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exit (1);
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}
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krb5_make_context (kc);
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c = (krb5_kx_context *)kc->data;
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context = c->context;
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ret = krb5_sock_to_principal (context, sock, "host",
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KRB5_NT_SRV_HST, &server);
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if (ret) {
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syslog (LOG_ERR, "krb5_sock_to_principal: %s",
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krb5_get_err_text (context, ret));
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exit (1);
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}
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ret = krb5_recvauth (context,
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&auth_context,
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&sock,
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KX_VERSION,
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server,
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KRB5_RECVAUTH_IGNORE_VERSION,
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NULL,
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&ticket);
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krb5_free_principal (context, server);
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if (ret) {
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syslog (LOG_ERR, "krb5_sock_to_principal: %s",
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krb5_get_err_text (context, ret));
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exit (1);
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}
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ret = krb5_auth_con_getkey (context, auth_context, &c->keyblock);
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if (ret) {
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syslog (LOG_ERR, "krb5_auth_con_getkey: %s",
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krb5_get_err_text (context, ret));
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exit (1);
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}
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ret = krb5_crypto_init (context, c->keyblock, 0, &c->crypto);
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if (ret) {
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syslog (LOG_ERR, "krb5_crypto_init: %s",
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krb5_get_err_text (context, ret));
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exit (1);
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}
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c->client = ticket->client;
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ticket->client = NULL;
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krb5_free_ticket (context, ticket);
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return 0;
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}
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#endif /* KRB5 */
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