appl/rsh/common.c

   1 /*
   2  * Copyright (c) 1997-2004 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "rsh_locl.h"
  35 RCSID("$Id$");
  36
  37 #if defined(KRB5)
  38
  39 #ifdef KRB5
  40 int key_usage = 1026;
  41
  42 void *ivec_in[2];
  43 void *ivec_out[2];
  44
  45 void
  46 init_ivecs(int client, int have_errsock)
  47 {
  48     size_t blocksize;
  49
  50     krb5_crypto_getblocksize(context, crypto, &blocksize);
  51
  52     ivec_in[0] = malloc(blocksize);
  53     memset(ivec_in[0], client, blocksize);
  54
  55     if(have_errsock) {
  56         ivec_in[1] = malloc(blocksize);
  57         memset(ivec_in[1], 2 | client, blocksize);
  58     } else
  59         ivec_in[1] = ivec_in[0];
  60
  61     ivec_out[0] = malloc(blocksize);
  62     memset(ivec_out[0], !client, blocksize);
  63
  64     if(have_errsock) {
  65         ivec_out[1] = malloc(blocksize);
  66         memset(ivec_out[1], 2 | !client, blocksize);
  67     } else
  68         ivec_out[1] = ivec_out[0];
  69 }
  70 #endif
  71
  72
  73 ssize_t
  74 do_read (int fd, void *buf, size_t sz, void *ivec)
  75 {
  76     if (do_encrypt) {
  77 #ifdef KRB5
  78         if(auth_method == AUTH_KRB5) {
  79             krb5_error_code ret;
  80             uint32_t len, outer_len;
  81             int status;
  82             krb5_data data;
  83             void *edata;
  84
  85             ret = krb5_net_read (context, &fd, &len, 4);
  86             if (ret <= 0)
  87                 return ret;
  88             len = ntohl(len);
  89             if (len > sz)
  90                 abort ();
  91             /* ivec will be non null for protocol version 2 */
  92             if(ivec != NULL)
  93                 outer_len = krb5_get_wrapped_length (context, crypto, len + 4);
  94             else
  95                 outer_len = krb5_get_wrapped_length (context, crypto, len);
  96             edata = malloc (outer_len);
  97             if (edata == NULL)
  98                 errx (1, "malloc: cannot allocate %u bytes", outer_len);
  99             ret = krb5_net_read (context, &fd, edata, outer_len);
 100             if (ret <= 0) {
 101                 free(edata);
 102                 return ret;
 103             }
 104
 105             status = krb5_decrypt_ivec(context, crypto, key_usage,
 106                                        edata, outer_len, &data, ivec);
 107             free (edata);
 108
 109             if (status)
 110                 krb5_err (context, 1, status, "decrypting data");
 111             if(ivec != NULL) {
 112                 unsigned long l;
 113                 if(data.length < len + 4)
 114                     errx (1, "data received is too short");
 115                 _krb5_get_int(data.data, &l, 4);
 116                 if(l != len)
 117                     errx (1, "inconsistency in received data");
 118                 memcpy (buf, (unsigned char *)data.data+4, len);
 119             } else
 120                 memcpy (buf, data.data, len);
 121             krb5_data_free (&data);
 122             return len;
 123         } else
 124 #endif /* KRB5 */
 125             abort ();
 126     } else
 127         return read (fd, buf, sz);
 128 }
 129
 130 ssize_t
 131 do_write (int fd, void *buf, size_t sz, void *ivec)
 132 {
 133     if (do_encrypt) {
 134 #ifdef KRB5
 135         if(auth_method == AUTH_KRB5) {
 136             krb5_error_code status;
 137             krb5_data data;
 138             unsigned char len[4];
 139             int ret;
 140
 141             _krb5_put_int(len, sz, 4);
 142             if(ivec != NULL) {
 143                 unsigned char *tmp = malloc(sz + 4);
 144                 if(tmp == NULL)
 145                     err(1, "malloc");
 146                 _krb5_put_int(tmp, sz, 4);
 147                 memcpy(tmp + 4, buf, sz);
 148                 status = krb5_encrypt_ivec(context, crypto, key_usage,
 149                                            tmp, sz + 4, &data, ivec);
 150                 free(tmp);
 151             } else
 152                 status = krb5_encrypt_ivec(context, crypto, key_usage,
 153                                            buf, sz, &data, ivec);
 154
 155             if (status)
 156                 krb5_err(context, 1, status, "encrypting data");
 157
 158             ret = krb5_net_write (context, &fd, len, 4);
 159             if (ret != 4)
 160                 return ret;
 161             ret = krb5_net_write (context, &fd, data.data, data.length);
 162             if (ret != data.length)
 163                 return ret;
 164             free (data.data);
 165             return sz;
 166         } else
 167 #endif /* KRB5 */
 168             abort();
 169     } else
 170         return write (fd, buf, sz);
 171 }
 172 #endif /* KRB5 */