394 lines
10 KiB
C
394 lines
10 KiB
C
/* $NetBSD: ns_sign.c,v 1.2 2022/04/19 20:32:17 rillig Exp $ */
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/*
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* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
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* Copyright (c) 1999 by Internet Software Consortium, Inc.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <sys/cdefs.h>
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#if 0
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static const char rcsid[] = "Id: ns_sign.c,v 1.6 2006/03/09 23:57:56 marka Exp ";
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#else
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__RCSID("$NetBSD: ns_sign.c,v 1.2 2022/04/19 20:32:17 rillig Exp $");
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#endif
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/* Import. */
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#include "port_before.h"
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#include "fd_setsize.h"
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#include <sys/types.h>
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#include <sys/param.h>
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#include <netinet/in.h>
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#include <arpa/nameser.h>
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#include <arpa/inet.h>
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#include <errno.h>
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#include <netdb.h>
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#include <resolv.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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#include <isc/dst.h>
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#include <isc/assertions.h>
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#include "port_after.h"
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#define BOUNDS_CHECK(ptr, count) \
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do { \
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if ((ptr) + (count) > eob) { \
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errno = EMSGSIZE; \
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return(NS_TSIG_ERROR_NO_SPACE); \
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} \
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} while (0)
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/*%
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* ns_sign
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*
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* Parameters:
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*\li msg message to be sent
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*\li msglen input - length of message
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* output - length of signed message
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*\li msgsize length of buffer containing message
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*\li error value to put in the error field
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*\li key tsig key used for signing
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*\li querysig (response), the signature in the query
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*\li querysiglen (response), the length of the signature in the query
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*\li sig a buffer to hold the generated signature
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*\li siglen input - length of signature buffer
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* output - length of signature
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*
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* Errors:
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*\li - bad input data (-1)
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*\li - bad key / sign failed (-BADKEY)
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*\li - not enough space (NS_TSIG_ERROR_NO_SPACE)
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*/
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int
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ns_sign(u_char *msg, int *msglen, int msgsize, int error, void *k,
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const u_char *querysig, int querysiglen, u_char *sig, int *siglen,
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time_t in_timesigned)
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{
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return(ns_sign2(msg, msglen, msgsize, error, k,
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querysig, querysiglen, sig, siglen,
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in_timesigned, NULL, NULL));
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}
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int
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ns_sign2(u_char *msg, int *msglen, int msgsize, int error, void *k,
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const u_char *querysig, int querysiglen, u_char *sig, int *siglen,
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time_t in_timesigned, u_char **dnptrs, u_char **lastdnptr)
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{
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HEADER *hp = (void *)msg;
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DST_KEY *key = (DST_KEY *)k;
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u_char *cp, *eob;
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u_char *lenp;
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u_char *alg;
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int n;
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time_t timesigned;
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u_char name[NS_MAXCDNAME];
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dst_init();
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if (msg == NULL || msglen == NULL || sig == NULL || siglen == NULL)
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return (-1);
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cp = msg + *msglen;
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eob = msg + msgsize;
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/* Name. */
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if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
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n = ns_name_pton(key->dk_key_name, name, sizeof name);
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if (n != -1)
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n = ns_name_pack(name, cp, (int)(eob - cp),
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(void *)dnptrs,
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(void *)lastdnptr);
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} else {
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n = ns_name_pton("", name, sizeof name);
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if (n != -1)
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n = ns_name_pack(name, cp, (int)(eob - cp), NULL, NULL);
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}
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if (n < 0)
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return (NS_TSIG_ERROR_NO_SPACE);
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cp += n;
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/* Type, class, ttl, length (not filled in yet). */
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BOUNDS_CHECK(cp, INT16SZ + INT16SZ + INT32SZ + INT16SZ);
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PUTSHORT(ns_t_tsig, cp);
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PUTSHORT(ns_c_any, cp);
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PUTLONG(0, cp); /*%< TTL */
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lenp = cp;
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cp += 2;
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/* Alg. */
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if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
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if (key->dk_alg != KEY_HMAC_MD5)
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return (-ns_r_badkey);
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n = dn_comp(NS_TSIG_ALG_HMAC_MD5, cp, (int)(eob - cp), NULL,
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NULL);
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}
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else
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n = dn_comp("", cp, (int)(eob - cp), NULL, NULL);
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if (n < 0)
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return (NS_TSIG_ERROR_NO_SPACE);
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alg = cp;
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cp += n;
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/* Time. */
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BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
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PUTSHORT(0, cp);
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timesigned = time(NULL);
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if (error != ns_r_badtime)
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PUTLONG(timesigned, cp);
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else
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PUTLONG(in_timesigned, cp);
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PUTSHORT(NS_TSIG_FUDGE, cp);
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/* Compute the signature. */
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if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
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void *ctx;
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u_char buf[NS_MAXCDNAME], *cp2;
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int nn;
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dst_sign_data(SIG_MODE_INIT, key, &ctx, NULL, 0, NULL, 0);
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/* Digest the query signature, if this is a response. */
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if (querysiglen > 0 && querysig != NULL) {
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u_int16_t len_n = htons(querysiglen);
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dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
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(void *)&len_n, INT16SZ, NULL, 0);
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dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
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querysig, querysiglen, NULL, 0);
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}
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/* Digest the message. */
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dst_sign_data(SIG_MODE_UPDATE, key, &ctx, msg, *msglen,
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NULL, 0);
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/* Digest the key name. */
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nn = ns_name_ntol(name, buf, sizeof(buf));
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INSIST(nn > 0);
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dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, nn, NULL, 0);
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/* Digest the class and TTL. */
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cp2 = buf;
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PUTSHORT(ns_c_any, cp2);
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PUTLONG(0, cp2);
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dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, (int)(cp2 - buf),
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NULL, 0);
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/* Digest the algorithm. */
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nn = ns_name_ntol(alg, buf, sizeof(buf));
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INSIST(nn > 0);
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dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, nn, NULL, 0);
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/* Digest the time signed, fudge, error, and other data */
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cp2 = buf;
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PUTSHORT(0, cp2); /*%< Top 16 bits of time */
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if (error != ns_r_badtime)
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PUTLONG(timesigned, cp2);
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else
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PUTLONG(in_timesigned, cp2);
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PUTSHORT(NS_TSIG_FUDGE, cp2);
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PUTSHORT(error, cp2); /*%< Error */
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if (error != ns_r_badtime)
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PUTSHORT(0, cp2); /*%< Other data length */
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else {
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PUTSHORT(INT16SZ+INT32SZ, cp2); /*%< Other data length */
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PUTSHORT(0, cp2); /*%< Top 16 bits of time */
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PUTLONG(timesigned, cp2);
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}
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dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, (int)(cp2 - buf),
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NULL, 0);
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nn = dst_sign_data(SIG_MODE_FINAL, key, &ctx, NULL, 0,
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sig, *siglen);
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if (nn < 0)
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return (-ns_r_badkey);
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*siglen = nn;
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} else
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*siglen = 0;
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/* Add the signature. */
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BOUNDS_CHECK(cp, INT16SZ + (*siglen));
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PUTSHORT(*siglen, cp);
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memcpy(cp, sig, *siglen);
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cp += (*siglen);
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/* The original message ID & error. */
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BOUNDS_CHECK(cp, INT16SZ + INT16SZ);
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PUTSHORT(ntohs(hp->id), cp); /*%< already in network order */
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PUTSHORT(error, cp);
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/* Other data. */
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BOUNDS_CHECK(cp, INT16SZ);
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if (error != ns_r_badtime)
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PUTSHORT(0, cp); /*%< Other data length */
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else {
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PUTSHORT(INT16SZ+INT32SZ, cp); /*%< Other data length */
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BOUNDS_CHECK(cp, INT32SZ+INT16SZ);
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PUTSHORT(0, cp); /*%< Top 16 bits of time */
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PUTLONG(timesigned, cp);
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}
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/* Go back and fill in the length. */
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PUTSHORT(cp - lenp - INT16SZ, lenp);
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hp->arcount = htons(ntohs(hp->arcount) + 1);
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*msglen = (int)(cp - msg);
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return (0);
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}
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int
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ns_sign_tcp_init(void *k, const u_char *querysig, int querysiglen,
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ns_tcp_tsig_state *state)
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{
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dst_init();
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if (state == NULL || k == NULL || querysig == NULL || querysiglen < 0)
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return (-1);
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state->counter = -1;
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state->key = k;
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if (state->key->dk_alg != KEY_HMAC_MD5)
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return (-ns_r_badkey);
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if (querysiglen > (int)sizeof(state->sig))
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return (-1);
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memcpy(state->sig, querysig, querysiglen);
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state->siglen = querysiglen;
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return (0);
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}
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int
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ns_sign_tcp(u_char *msg, int *msglen, int msgsize, int error,
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ns_tcp_tsig_state *state, int done)
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{
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return (ns_sign_tcp2(msg, msglen, msgsize, error, state,
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done, NULL, NULL));
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}
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int
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ns_sign_tcp2(u_char *msg, int *msglen, int msgsize, int error,
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ns_tcp_tsig_state *state, int done,
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u_char **dnptrs, u_char **lastdnptr)
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{
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u_char *cp, *eob, *lenp;
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u_char buf[MAXDNAME], *cp2;
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HEADER *hp = (void *)msg;
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time_t timesigned;
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int n;
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if (msg == NULL || msglen == NULL || state == NULL)
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return (-1);
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state->counter++;
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if (state->counter == 0)
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return (ns_sign2(msg, msglen, msgsize, error, state->key,
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state->sig, state->siglen,
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state->sig, &state->siglen, 0,
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dnptrs, lastdnptr));
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if (state->siglen > 0) {
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u_int16_t siglen_n = htons(state->siglen);
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dst_sign_data(SIG_MODE_INIT, state->key, &state->ctx,
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NULL, 0, NULL, 0);
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dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
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(void *)&siglen_n, INT16SZ, NULL, 0);
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dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
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state->sig, state->siglen, NULL, 0);
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state->siglen = 0;
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}
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dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx, msg, *msglen,
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NULL, 0);
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if (done == 0 && (state->counter % 100 != 0))
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return (0);
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cp = msg + *msglen;
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eob = msg + msgsize;
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/* Name. */
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n = dn_comp(state->key->dk_key_name, cp, (int)(eob - cp), dnptrs,
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lastdnptr);
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if (n < 0)
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return (NS_TSIG_ERROR_NO_SPACE);
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cp += n;
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/* Type, class, ttl, length (not filled in yet). */
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BOUNDS_CHECK(cp, INT16SZ + INT16SZ + INT32SZ + INT16SZ);
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PUTSHORT(ns_t_tsig, cp);
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PUTSHORT(ns_c_any, cp);
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PUTLONG(0, cp); /*%< TTL */
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lenp = cp;
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cp += 2;
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/* Alg. */
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n = dn_comp(NS_TSIG_ALG_HMAC_MD5, cp, (int)(eob - cp), NULL, NULL);
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if (n < 0)
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return (NS_TSIG_ERROR_NO_SPACE);
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cp += n;
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/* Time. */
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BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
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PUTSHORT(0, cp);
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timesigned = time(NULL);
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PUTLONG(timesigned, cp);
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PUTSHORT(NS_TSIG_FUDGE, cp);
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/*
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* Compute the signature.
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*/
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/* Digest the time signed and fudge. */
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cp2 = buf;
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PUTSHORT(0, cp2); /*%< Top 16 bits of time */
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PUTLONG(timesigned, cp2);
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PUTSHORT(NS_TSIG_FUDGE, cp2);
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dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
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buf, (int)(cp2 - buf), NULL, 0);
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n = dst_sign_data(SIG_MODE_FINAL, state->key, &state->ctx, NULL, 0,
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state->sig, (int)sizeof(state->sig));
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if (n < 0)
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return (-ns_r_badkey);
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state->siglen = n;
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/* Add the signature. */
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BOUNDS_CHECK(cp, INT16SZ + state->siglen);
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PUTSHORT(state->siglen, cp);
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memcpy(cp, state->sig, state->siglen);
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cp += state->siglen;
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/* The original message ID & error. */
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BOUNDS_CHECK(cp, INT16SZ + INT16SZ);
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PUTSHORT(ntohs(hp->id), cp); /*%< already in network order */
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PUTSHORT(error, cp);
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/* Other data. */
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BOUNDS_CHECK(cp, INT16SZ);
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PUTSHORT(0, cp);
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/* Go back and fill in the length. */
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PUTSHORT(cp - lenp - INT16SZ, lenp);
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hp->arcount = htons(ntohs(hp->arcount) + 1);
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*msglen = (int)(cp - msg);
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return (0);
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}
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/*! \file */
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