155682Smarkm/* 2233294Sstas * Copyright (c) 1997 - 2003 Kungliga Tekniska H��gskolan 3233294Sstas * (Royal Institute of Technology, Stockholm, Sweden). 4233294Sstas * All rights reserved. 555682Smarkm * 6233294Sstas * Redistribution and use in source and binary forms, with or without 7233294Sstas * modification, are permitted provided that the following conditions 8233294Sstas * are met: 955682Smarkm * 10233294Sstas * 1. Redistributions of source code must retain the above copyright 11233294Sstas * notice, this list of conditions and the following disclaimer. 1255682Smarkm * 13233294Sstas * 2. Redistributions in binary form must reproduce the above copyright 14233294Sstas * notice, this list of conditions and the following disclaimer in the 15233294Sstas * documentation and/or other materials provided with the distribution. 1655682Smarkm * 17233294Sstas * 3. Neither the name of the Institute nor the names of its contributors 18233294Sstas * may be used to endorse or promote products derived from this software 19233294Sstas * without specific prior written permission. 2055682Smarkm * 21233294Sstas * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 22233294Sstas * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23233294Sstas * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24233294Sstas * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 25233294Sstas * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26233294Sstas * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27233294Sstas * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28233294Sstas * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29233294Sstas * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30233294Sstas * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31233294Sstas * SUCH DAMAGE. 3255682Smarkm */ 3355682Smarkm 34233294Sstas#include "krb5_locl.h" 3555682Smarkm 3655682Smarkmstatic krb5_error_code 3755682Smarkmverify_checksum(krb5_context context, 3855682Smarkm krb5_auth_context auth_context, 3955682Smarkm KRB_SAFE *safe) 4055682Smarkm{ 4155682Smarkm krb5_error_code ret; 4255682Smarkm u_char *buf; 4355682Smarkm size_t buf_size; 44233294Sstas size_t len = 0; 4555682Smarkm Checksum c; 4655682Smarkm krb5_crypto crypto; 4790926Snectar krb5_keyblock *key; 4855682Smarkm 4955682Smarkm c = safe->cksum; 5055682Smarkm safe->cksum.cksumtype = 0; 5155682Smarkm safe->cksum.checksum.data = NULL; 5255682Smarkm safe->cksum.checksum.length = 0; 5355682Smarkm 54103423Snectar ASN1_MALLOC_ENCODE(KRB_SAFE, buf, buf_size, safe, &len, ret); 55103423Snectar if(ret) 56103423Snectar return ret; 57103423Snectar if(buf_size != len) 58103423Snectar krb5_abortx(context, "internal error in ASN.1 encoder"); 5955682Smarkm 6090926Snectar if (auth_context->remote_subkey) 6190926Snectar key = auth_context->remote_subkey; 6290926Snectar else if (auth_context->local_subkey) 6390926Snectar key = auth_context->local_subkey; 6490926Snectar else 6590926Snectar key = auth_context->keyblock; 6690926Snectar 6790926Snectar ret = krb5_crypto_init(context, key, 0, &crypto); 6872445Sassar if (ret) 6972445Sassar goto out; 7055682Smarkm ret = krb5_verify_checksum (context, 7155682Smarkm crypto, 7255682Smarkm KRB5_KU_KRB_SAFE_CKSUM, 7355682Smarkm buf + buf_size - len, 7455682Smarkm len, 7555682Smarkm &c); 7655682Smarkm krb5_crypto_destroy(context, crypto); 7755682Smarkmout: 7855682Smarkm safe->cksum = c; 7955682Smarkm free (buf); 8055682Smarkm return ret; 8155682Smarkm} 8255682Smarkm 83233294SstasKRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL 8455682Smarkmkrb5_rd_safe(krb5_context context, 8555682Smarkm krb5_auth_context auth_context, 8655682Smarkm const krb5_data *inbuf, 8755682Smarkm krb5_data *outbuf, 88178825Sdfr krb5_replay_data *outdata) 8955682Smarkm{ 90178825Sdfr krb5_error_code ret; 91178825Sdfr KRB_SAFE safe; 92178825Sdfr size_t len; 9355682Smarkm 94233294Sstas krb5_data_zero(outbuf); 9555682Smarkm 96233294Sstas if ((auth_context->flags & 97233294Sstas (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE))) 98233294Sstas { 99233294Sstas if (outdata == NULL) { 100233294Sstas krb5_set_error_message(context, KRB5_RC_REQUIRED, 101233294Sstas N_("rd_safe: need outdata " 102233294Sstas "to return data", "")); 103233294Sstas return KRB5_RC_REQUIRED; /* XXX better error, MIT returns this */ 104233294Sstas } 105233294Sstas /* if these fields are not present in the safe-part, silently 106233294Sstas return zero */ 107233294Sstas memset(outdata, 0, sizeof(*outdata)); 108178825Sdfr } 10955682Smarkm 110178825Sdfr ret = decode_KRB_SAFE (inbuf->data, inbuf->length, &safe, &len); 111233294Sstas if (ret) 112178825Sdfr return ret; 113178825Sdfr if (safe.pvno != 5) { 114178825Sdfr ret = KRB5KRB_AP_ERR_BADVERSION; 115233294Sstas krb5_clear_error_message (context); 116178825Sdfr goto failure; 117178825Sdfr } 118178825Sdfr if (safe.msg_type != krb_safe) { 119178825Sdfr ret = KRB5KRB_AP_ERR_MSG_TYPE; 120233294Sstas krb5_clear_error_message (context); 121178825Sdfr goto failure; 122178825Sdfr } 123178825Sdfr if (!krb5_checksum_is_keyed(context, safe.cksum.cksumtype) 124178825Sdfr || !krb5_checksum_is_collision_proof(context, safe.cksum.cksumtype)) { 125178825Sdfr ret = KRB5KRB_AP_ERR_INAPP_CKSUM; 126233294Sstas krb5_clear_error_message (context); 127178825Sdfr goto failure; 128178825Sdfr } 12955682Smarkm 130178825Sdfr /* check sender address */ 13155682Smarkm 132178825Sdfr if (safe.safe_body.s_address 133178825Sdfr && auth_context->remote_address 134178825Sdfr && !krb5_address_compare (context, 135178825Sdfr auth_context->remote_address, 136178825Sdfr safe.safe_body.s_address)) { 137178825Sdfr ret = KRB5KRB_AP_ERR_BADADDR; 138233294Sstas krb5_clear_error_message (context); 139178825Sdfr goto failure; 140178825Sdfr } 14155682Smarkm 142178825Sdfr /* check receiver address */ 14355682Smarkm 144178825Sdfr if (safe.safe_body.r_address 145178825Sdfr && auth_context->local_address 146178825Sdfr && !krb5_address_compare (context, 147178825Sdfr auth_context->local_address, 148178825Sdfr safe.safe_body.r_address)) { 149178825Sdfr ret = KRB5KRB_AP_ERR_BADADDR; 150233294Sstas krb5_clear_error_message (context); 151178825Sdfr goto failure; 152178825Sdfr } 15355682Smarkm 154178825Sdfr /* check timestamp */ 155178825Sdfr if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) { 156178825Sdfr krb5_timestamp sec; 15755682Smarkm 158178825Sdfr krb5_timeofday (context, &sec); 15972445Sassar 160178825Sdfr if (safe.safe_body.timestamp == NULL || 161178825Sdfr safe.safe_body.usec == NULL || 162178825Sdfr abs(*safe.safe_body.timestamp - sec) > context->max_skew) { 163178825Sdfr ret = KRB5KRB_AP_ERR_SKEW; 164233294Sstas krb5_clear_error_message (context); 165178825Sdfr goto failure; 166178825Sdfr } 167178825Sdfr } 168178825Sdfr /* XXX - check replay cache */ 16955682Smarkm 170178825Sdfr /* check sequence number. since MIT krb5 cannot generate a sequence 171178825Sdfr number of zero but instead generates no sequence number, we accept that 172178825Sdfr */ 173178825Sdfr 174178825Sdfr if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) { 175178825Sdfr if ((safe.safe_body.seq_number == NULL 176178825Sdfr && auth_context->remote_seqnumber != 0) 177178825Sdfr || (safe.safe_body.seq_number != NULL 178178825Sdfr && *safe.safe_body.seq_number != 179178825Sdfr auth_context->remote_seqnumber)) { 180178825Sdfr ret = KRB5KRB_AP_ERR_BADORDER; 181233294Sstas krb5_clear_error_message (context); 182178825Sdfr goto failure; 183178825Sdfr } 184178825Sdfr auth_context->remote_seqnumber++; 185178825Sdfr } 186178825Sdfr 187178825Sdfr ret = verify_checksum (context, auth_context, &safe); 188178825Sdfr if (ret) 189178825Sdfr goto failure; 190233294Sstas 191178825Sdfr outbuf->length = safe.safe_body.user_data.length; 192178825Sdfr outbuf->data = malloc(outbuf->length); 193178825Sdfr if (outbuf->data == NULL && outbuf->length != 0) { 194178825Sdfr ret = ENOMEM; 195233294Sstas krb5_set_error_message(context, ret, N_("malloc: out of memory", "")); 196178825Sdfr krb5_data_zero(outbuf); 197178825Sdfr goto failure; 198178825Sdfr } 199178825Sdfr memcpy (outbuf->data, safe.safe_body.user_data.data, outbuf->length); 200178825Sdfr 201233294Sstas if ((auth_context->flags & 202178825Sdfr (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE))) { 203233294Sstas 204178825Sdfr if(safe.safe_body.timestamp) 205178825Sdfr outdata->timestamp = *safe.safe_body.timestamp; 206178825Sdfr if(safe.safe_body.usec) 207178825Sdfr outdata->usec = *safe.safe_body.usec; 208178825Sdfr if(safe.safe_body.seq_number) 209178825Sdfr outdata->seq = *safe.safe_body.seq_number; 210178825Sdfr } 211178825Sdfr 212178825Sdfr failure: 213178825Sdfr free_KRB_SAFE (&safe); 214178825Sdfr return ret; 21555682Smarkm} 216