47bdc7b536
This fixes a security vulnerability in the bundled resolver library. Requested by: scottl(re)
357 lines
9.4 KiB
C
357 lines
9.4 KiB
C
/*
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* Copyright (c) 1999-2003 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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS
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* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
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* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
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* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
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* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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* SOFTWARE.
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*/
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#ifndef lint
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static const char rcsid[] = "$Id: ns_sign.c,v 1.4.2.3 2003/01/14 23:15:06 dhankins Exp $";
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#endif
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#if defined (TRACING)
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#define time(x) trace_mr_time (x)
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time_t trace_mr_time (time_t *);
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#endif
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/* Import. */
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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/inet.h>
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#include <sys/socket.h>
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#include <errno.h>
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#include <netdb.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 <unistd.h>
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#include <time.h>
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#include "minires/minires.h"
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#include "arpa/nameser.h"
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#include <isc-dhcp/dst.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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return ISC_R_NOSPACE; \
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} \
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} while (0)
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/* ns_sign
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* Parameters:
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* msg message to be sent
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* msglen input - length of message
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* output - length of signed message
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* msgsize length of buffer containing message
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* error value to put in the error field
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* key tsig key used for signing
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* querysig (response), the signature in the query
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* querysiglen (response), the length of the signature in the query
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* sig a buffer to hold the generated signature
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* 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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* - bad input data (-1)
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* - bad key / sign failed (-BADKEY)
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* - not enough space (NS_TSIG_ERROR_NO_SPACE)
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*/
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isc_result_t
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ns_sign(u_char *msg, unsigned *msglen, unsigned msgsize, int error, void *k,
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const u_char *querysig, unsigned querysiglen, u_char *sig,
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unsigned *siglen, time_t in_timesigned)
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{
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HEADER *hp = (HEADER *)msg;
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DST_KEY *key = (DST_KEY *)k;
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u_char *cp = msg + *msglen, *eob = msg + msgsize;
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u_char *lenp;
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u_char *name, *alg;
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unsigned n;
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time_t timesigned;
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dst_init();
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if (msg == NULL || msglen == NULL || sig == NULL || siglen == NULL)
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return ISC_R_INVALIDARG;
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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 = dn_comp(key->dk_key_name,
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cp, (unsigned)(eob - cp), NULL, NULL);
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else
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n = dn_comp("", cp, (unsigned)(eob - cp), NULL, NULL);
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if (n < 0)
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return ISC_R_NOSPACE;
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name = cp;
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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 ISC_R_BADKEY;
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n = dn_comp(NS_TSIG_ALG_HMAC_MD5,
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cp, (unsigned)(eob - cp), NULL, NULL);
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}
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else
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n = dn_comp("", cp, (unsigned)(eob - cp), NULL, NULL);
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if (n < 0)
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return ISC_R_NOSPACE;
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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[MAXDNAME], *cp2;
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unsigned n;
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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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(u_char *)&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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n = ns_name_ntol(name, buf, sizeof(buf));
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dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, n, 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,
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buf, (unsigned)(cp2-buf), NULL, 0);
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/* Digest the algorithm. */
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n = ns_name_ntol(alg, buf, sizeof(buf));
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dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, n, 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,
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buf, (unsigned)(cp2-buf), NULL, 0);
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n = dst_sign_data(SIG_MODE_FINAL, key, &ctx, NULL, 0,
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sig, *siglen);
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if (n < 0)
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return ISC_R_BADKEY;
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*siglen = n;
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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 = (cp - msg);
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return ISC_R_SUCCESS;
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}
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#if 0
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isc_result_t
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ns_sign_tcp_init(void *k, const u_char *querysig, unsigned 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 ISC_R_INVALIDARG;
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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 ISC_R_BADKEY;
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if (querysiglen > sizeof(state->sig))
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return ISC_R_NOSPACE;
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memcpy(state->sig, querysig, querysiglen);
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state->siglen = querysiglen;
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return ISC_R_SUCCESS;
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}
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isc_result_t
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ns_sign_tcp(u_char *msg, unsigned *msglen, unsigned msgsize, int error,
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ns_tcp_tsig_state *state, int done)
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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 = (HEADER *)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 ISC_R_INVALIDARG;
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state->counter++;
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if (state->counter == 0)
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return ns_sign(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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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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(u_char *)&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 ISC_R_SUCCESS;
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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,
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cp, (unsigned)(eob - cp), NULL, NULL);
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if (n < 0)
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return ISC_R_NOSPACE;
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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,
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cp, (unsigned)(eob - cp), NULL, NULL);
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if (n < 0)
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return ISC_R_NOSPACE;
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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, (unsigned)(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, sizeof(state->sig));
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if (n < 0)
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return ISC_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 = (cp - msg);
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return ISC_R_SUCCESS;
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}
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#endif
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