1 /* 2 * Copyright (c) 1997 - 2000 Kungliga Tekniska H�gskolan 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 <krb5_locl.h> 35 36 RCSID("$Id: rd_safe.c,v 1.19 2000/02/06 05:20:51 assar Exp $"); 37 38 static krb5_error_code 39 verify_checksum(krb5_context context, 40 krb5_auth_context auth_context, 41 KRB_SAFE *safe) 42 { 43 krb5_error_code ret; 44 u_char *buf; 45 size_t buf_size; 46 size_t len; 47 Checksum c; 48 krb5_crypto crypto; 49 50 c = safe->cksum; 51 safe->cksum.cksumtype = 0; 52 safe->cksum.checksum.data = NULL; 53 safe->cksum.checksum.length = 0; 54 55 56 buf_size = length_KRB_SAFE(safe); 57 buf = malloc(buf_size); 58 59 if (buf == NULL) { 60 ret = ENOMEM; 61 goto out; 62 } 63 64 ret = encode_KRB_SAFE (buf + buf_size - 1, 65 buf_size, 66 safe, 67 &len); 68 krb5_crypto_init(context, auth_context->keyblock, 0, &crypto); 69 ret = krb5_verify_checksum (context, 70 crypto, 71 KRB5_KU_KRB_SAFE_CKSUM, 72 buf + buf_size - len, 73 len, 74 &c); 75 krb5_crypto_destroy(context, crypto); 76 out: 77 safe->cksum = c; 78 free (buf); 79 return ret; 80 } 81 82 krb5_error_code 83 krb5_rd_safe(krb5_context context, 84 krb5_auth_context auth_context, 85 const krb5_data *inbuf, 86 krb5_data *outbuf, 87 /*krb5_replay_data*/ void *outdata) 88 { 89 krb5_error_code ret; 90 KRB_SAFE safe; 91 size_t len; 92 93 ret = decode_KRB_SAFE (inbuf->data, inbuf->length, &safe, &len); 94 if (ret) 95 return ret; 96 if (safe.pvno != 5) { 97 ret = KRB5KRB_AP_ERR_BADVERSION; 98 goto failure; 99 } 100 if (safe.msg_type != krb_safe) { 101 ret = KRB5KRB_AP_ERR_MSG_TYPE; 102 goto failure; 103 } 104 if (!krb5_checksum_is_keyed(context, safe.cksum.cksumtype) 105 || !krb5_checksum_is_collision_proof(context, safe.cksum.cksumtype)) { 106 ret = KRB5KRB_AP_ERR_INAPP_CKSUM; 107 goto failure; 108 } 109 110 /* check sender address */ 111 112 if (safe.safe_body.s_address 113 && auth_context->remote_address 114 && !krb5_address_compare (context, 115 auth_context->remote_address, 116 safe.safe_body.s_address)) { 117 ret = KRB5KRB_AP_ERR_BADADDR; 118 goto failure; 119 } 120 121 /* check receiver address */ 122 123 if (safe.safe_body.r_address 124 && auth_context->local_address 125 && !krb5_address_compare (context, 126 auth_context->local_address, 127 safe.safe_body.r_address)) { 128 ret = KRB5KRB_AP_ERR_BADADDR; 129 goto failure; 130 } 131 132 /* check timestamp */ 133 if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) { 134 krb5_timestamp sec; 135 136 krb5_timeofday (context, &sec); 137 138 if (safe.safe_body.timestamp == NULL || 139 safe.safe_body.usec == NULL || 140 abs(*safe.safe_body.timestamp - sec) > context->max_skew) { 141 ret = KRB5KRB_AP_ERR_SKEW; 142 goto failure; 143 } 144 } 145 /* XXX - check replay cache */ 146 147 /* check sequence number */ 148 if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) { 149 if (safe.safe_body.seq_number == NULL || 150 *safe.safe_body.seq_number != ++auth_context->remote_seqnumber) { 151 ret = KRB5KRB_AP_ERR_BADORDER; 152 goto failure; 153 } 154 } 155 156 ret = verify_checksum (context, auth_context, &safe); 157 if (ret) 158 goto failure; 159 160 outbuf->length = safe.safe_body.user_data.length; 161 outbuf->data = malloc(outbuf->length); 162 if (outbuf->data == NULL) { 163 ret = ENOMEM; 164 goto failure; 165 } 166 memcpy (outbuf->data, safe.safe_body.user_data.data, outbuf->length); 167 free_KRB_SAFE (&safe); 168 return 0; 169 failure: 170 free_KRB_SAFE (&safe); 171 return ret; 172 } 173