/*      $NetBSD: ns_sign.c,v 1.1.1.2 2012/09/09 16:08:05 christos Exp $ */

/*
* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
* Copyright (c) 1999 by Internet Software Consortium, Inc.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

#ifndef lint
static const char rcsid[] = "Id: ns_sign.c,v 1.6 2006/03/09 23:57:56 marka Exp ";
#endif

/* Import. */

#include "port_before.h"
#include "fd_setsize.h"

#include <sys/types.h>
#include <sys/param.h>

#include <netinet/in.h>
#include <arpa/nameser.h>
#include <arpa/inet.h>

#include <errno.h>
#include <netdb.h>
#include <resolv.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include <isc/dst.h>
#include <isc/assertions.h>

#include "port_after.h"

#define BOUNDS_CHECK(ptr, count) \
       do { \
               if ((ptr) + (count) > eob) { \
                       errno = EMSGSIZE; \
                       return(NS_TSIG_ERROR_NO_SPACE); \
               } \
       } while (0)

/*%
*  ns_sign
*
* Parameters:
*\li   msg             message to be sent
*\li   msglen          input - length of message
*                      output - length of signed message
*\li   msgsize         length of buffer containing message
*\li   error           value to put in the error field
*\li   key             tsig key used for signing
*\li   querysig        (response), the signature in the query
*\li   querysiglen     (response), the length of the signature in the query
*\li   sig             a buffer to hold the generated signature
*\li   siglen          input - length of signature buffer
*                      output - length of signature
*
* Errors:
*\li   - bad input data (-1)
*\li   - bad key / sign failed (-BADKEY)
*\li   - not enough space (NS_TSIG_ERROR_NO_SPACE)
*/
int
ns_sign(u_char *msg, int *msglen, int msgsize, int error, void *k,
       const u_char *querysig, int querysiglen, u_char *sig, int *siglen,
       time_t in_timesigned)
{
       return(ns_sign2(msg, msglen, msgsize, error, k,
                       querysig, querysiglen, sig, siglen,
                       in_timesigned, NULL, NULL));
}

int
ns_sign2(u_char *msg, int *msglen, int msgsize, int error, void *k,
        const u_char *querysig, int querysiglen, u_char *sig, int *siglen,
        time_t in_timesigned, u_char **dnptrs, u_char **lastdnptr)
{
       HEADER *hp = (HEADER *)msg;
       DST_KEY *key = (DST_KEY *)k;
       u_char *cp, *eob;
       u_char *lenp;
       u_char *alg;
       int n;
       time_t timesigned;
       u_char name[NS_MAXCDNAME];

       dst_init();
       if (msg == NULL || msglen == NULL || sig == NULL || siglen == NULL)
               return (-1);

       cp = msg + *msglen;
       eob = msg + msgsize;

       /* Name. */
       if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
               n = ns_name_pton(key->dk_key_name, name, sizeof name);
               if (n != -1)
                       n = ns_name_pack(name, cp, eob - cp,
                                        (const u_char **)dnptrs,
                                        (const u_char **)lastdnptr);

       } else {
               n = ns_name_pton("", name, sizeof name);
               if (n != -1)
                       n = ns_name_pack(name, cp, eob - cp, NULL, NULL);
       }
       if (n < 0)
               return (NS_TSIG_ERROR_NO_SPACE);
       cp += n;

       /* Type, class, ttl, length (not filled in yet). */
       BOUNDS_CHECK(cp, INT16SZ + INT16SZ + INT32SZ + INT16SZ);
       PUTSHORT(ns_t_tsig, cp);
       PUTSHORT(ns_c_any, cp);
       PUTLONG(0, cp);         /*%< TTL */
       lenp = cp;
       cp += 2;

       /* Alg. */
       if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
               if (key->dk_alg != KEY_HMAC_MD5)
                       return (-ns_r_badkey);
               n = dn_comp(NS_TSIG_ALG_HMAC_MD5, cp, eob - cp, NULL, NULL);
       }
       else
               n = dn_comp("", cp, eob - cp, NULL, NULL);
       if (n < 0)
               return (NS_TSIG_ERROR_NO_SPACE);
       alg = cp;
       cp += n;

       /* Time. */
       BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
       PUTSHORT(0, cp);
       timesigned = time(NULL);
       if (error != ns_r_badtime)
               PUTLONG(timesigned, cp);
       else
               PUTLONG(in_timesigned, cp);
       PUTSHORT(NS_TSIG_FUDGE, cp);

       /* Compute the signature. */
       if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
               void *ctx;
               u_char buf[NS_MAXCDNAME], *cp2;
               int n;

               dst_sign_data(SIG_MODE_INIT, key, &ctx, NULL, 0, NULL, 0);

               /* Digest the query signature, if this is a response. */
               if (querysiglen > 0 && querysig != NULL) {
                       u_int16_t len_n = htons(querysiglen);
                       dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
                                     (u_char *)&len_n, INT16SZ, NULL, 0);
                       dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
                                     querysig, querysiglen, NULL, 0);
               }

               /* Digest the message. */
               dst_sign_data(SIG_MODE_UPDATE, key, &ctx, msg, *msglen,
                             NULL, 0);

               /* Digest the key name. */
               n = ns_name_ntol(name, buf, sizeof(buf));
               INSIST(n > 0);
               dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, n, NULL, 0);

               /* Digest the class and TTL. */
               cp2 = buf;
               PUTSHORT(ns_c_any, cp2);
               PUTLONG(0, cp2);
               dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, cp2-buf,
                             NULL, 0);

               /* Digest the algorithm. */
               n = ns_name_ntol(alg, buf, sizeof(buf));
               INSIST(n > 0);
               dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, n, NULL, 0);

               /* Digest the time signed, fudge, error, and other data */
               cp2 = buf;
               PUTSHORT(0, cp2);       /*%< Top 16 bits of time */
               if (error != ns_r_badtime)
                       PUTLONG(timesigned, cp2);
               else
                       PUTLONG(in_timesigned, cp2);
               PUTSHORT(NS_TSIG_FUDGE, cp2);
               PUTSHORT(error, cp2);   /*%< Error */
               if (error != ns_r_badtime)
                       PUTSHORT(0, cp2);       /*%< Other data length */
               else {
                       PUTSHORT(INT16SZ+INT32SZ, cp2); /*%< Other data length */
                       PUTSHORT(0, cp2);       /*%< Top 16 bits of time */
                       PUTLONG(timesigned, cp2);
               }
               dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, cp2-buf,
                             NULL, 0);

               n = dst_sign_data(SIG_MODE_FINAL, key, &ctx, NULL, 0,
                                 sig, *siglen);
               if (n < 0)
                       return (-ns_r_badkey);
               *siglen = n;
       } else
               *siglen = 0;

       /* Add the signature. */
       BOUNDS_CHECK(cp, INT16SZ + (*siglen));
       PUTSHORT(*siglen, cp);
       memcpy(cp, sig, *siglen);
       cp += (*siglen);

       /* The original message ID & error. */
       BOUNDS_CHECK(cp, INT16SZ + INT16SZ);
       PUTSHORT(ntohs(hp->id), cp);    /*%< already in network order */
       PUTSHORT(error, cp);

       /* Other data. */
       BOUNDS_CHECK(cp, INT16SZ);
       if (error != ns_r_badtime)
               PUTSHORT(0, cp);        /*%< Other data length */
       else {
               PUTSHORT(INT16SZ+INT32SZ, cp);  /*%< Other data length */
               BOUNDS_CHECK(cp, INT32SZ+INT16SZ);
               PUTSHORT(0, cp);        /*%< Top 16 bits of time */
               PUTLONG(timesigned, cp);
       }

       /* Go back and fill in the length. */
       PUTSHORT(cp - lenp - INT16SZ, lenp);

       hp->arcount = htons(ntohs(hp->arcount) + 1);
       *msglen = (cp - msg);
       return (0);
}

int
ns_sign_tcp_init(void *k, const u_char *querysig, int querysiglen,
                ns_tcp_tsig_state *state)
{
       dst_init();
       if (state == NULL || k == NULL || querysig == NULL || querysiglen < 0)
               return (-1);
       state->counter = -1;
       state->key = k;
       if (state->key->dk_alg != KEY_HMAC_MD5)
               return (-ns_r_badkey);
       if (querysiglen > (int)sizeof(state->sig))
               return (-1);
       memcpy(state->sig, querysig, querysiglen);
       state->siglen = querysiglen;
       return (0);
}

int
ns_sign_tcp(u_char *msg, int *msglen, int msgsize, int error,
           ns_tcp_tsig_state *state, int done)
{
       return (ns_sign_tcp2(msg, msglen, msgsize, error, state,
                            done, NULL, NULL));
}

int
ns_sign_tcp2(u_char *msg, int *msglen, int msgsize, int error,
            ns_tcp_tsig_state *state, int done,
            u_char **dnptrs, u_char **lastdnptr)
{
       u_char *cp, *eob, *lenp;
       u_char buf[MAXDNAME], *cp2;
       HEADER *hp = (HEADER *)msg;
       time_t timesigned;
       int n;

       if (msg == NULL || msglen == NULL || state == NULL)
               return (-1);

       state->counter++;
       if (state->counter == 0)
               return (ns_sign2(msg, msglen, msgsize, error, state->key,
                                state->sig, state->siglen,
                                state->sig, &state->siglen, 0,
                                dnptrs, lastdnptr));

       if (state->siglen > 0) {
               u_int16_t siglen_n = htons(state->siglen);
               dst_sign_data(SIG_MODE_INIT, state->key, &state->ctx,
                             NULL, 0, NULL, 0);
               dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
                             (u_char *)&siglen_n, INT16SZ, NULL, 0);
               dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
                             state->sig, state->siglen, NULL, 0);
               state->siglen = 0;
       }

       dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx, msg, *msglen,
                     NULL, 0);

       if (done == 0 && (state->counter % 100 != 0))
               return (0);

       cp = msg + *msglen;
       eob = msg + msgsize;

       /* Name. */
       n = dn_comp(state->key->dk_key_name, cp, eob - cp, dnptrs, lastdnptr);
       if (n < 0)
               return (NS_TSIG_ERROR_NO_SPACE);
       cp += n;

       /* Type, class, ttl, length (not filled in yet). */
       BOUNDS_CHECK(cp, INT16SZ + INT16SZ + INT32SZ + INT16SZ);
       PUTSHORT(ns_t_tsig, cp);
       PUTSHORT(ns_c_any, cp);
       PUTLONG(0, cp);         /*%< TTL */
       lenp = cp;
       cp += 2;

       /* Alg. */
       n = dn_comp(NS_TSIG_ALG_HMAC_MD5, cp, eob - cp, NULL, NULL);
       if (n < 0)
               return (NS_TSIG_ERROR_NO_SPACE);
       cp += n;

       /* Time. */
       BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
       PUTSHORT(0, cp);
       timesigned = time(NULL);
       PUTLONG(timesigned, cp);
       PUTSHORT(NS_TSIG_FUDGE, cp);

       /*
        * Compute the signature.
        */

       /* Digest the time signed and fudge. */
       cp2 = buf;
       PUTSHORT(0, cp2);       /*%< Top 16 bits of time */
       PUTLONG(timesigned, cp2);
       PUTSHORT(NS_TSIG_FUDGE, cp2);

       dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
                     buf, cp2 - buf, NULL, 0);

       n = dst_sign_data(SIG_MODE_FINAL, state->key, &state->ctx, NULL, 0,
                         state->sig, sizeof(state->sig));
       if (n < 0)
               return (-ns_r_badkey);
       state->siglen = n;

       /* Add the signature. */
       BOUNDS_CHECK(cp, INT16SZ + state->siglen);
       PUTSHORT(state->siglen, cp);
       memcpy(cp, state->sig, state->siglen);
       cp += state->siglen;

       /* The original message ID & error. */
       BOUNDS_CHECK(cp, INT16SZ + INT16SZ);
       PUTSHORT(ntohs(hp->id), cp);    /*%< already in network order */
       PUTSHORT(error, cp);

       /* Other data. */
       BOUNDS_CHECK(cp, INT16SZ);
       PUTSHORT(0, cp);

       /* Go back and fill in the length. */
       PUTSHORT(cp - lenp - INT16SZ, lenp);

       hp->arcount = htons(ntohs(hp->arcount) + 1);
       *msglen = (cp - msg);
       return (0);
}

/*! \file */

You are viewing proxied material from ftp.icm.edu.pl. The copyright of proxied material belongs to its original authors. Any comments or complaints in relation to proxied material should be directed to the original authors of the content concerned. Please see the disclaimer for more details.