473 lines
12 KiB
C
473 lines
12 KiB
C
/*
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* tsig.c
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*
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* contains the functions needed for TSIG [RFC2845]
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*
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* (c) 2005-2006 NLnet Labs
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* See the file LICENSE for the license
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*/
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#include <ldns/config.h>
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#include <ldns/ldns.h>
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#include <strings.h>
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#ifdef HAVE_SSL
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#include <openssl/hmac.h>
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#include <openssl/md5.h>
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#endif /* HAVE_SSL */
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char *
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ldns_tsig_algorithm(ldns_tsig_credentials *tc)
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{
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return tc->algorithm;
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}
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char *
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ldns_tsig_keyname(ldns_tsig_credentials *tc)
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{
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return tc->keyname;
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}
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char *
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ldns_tsig_keydata(ldns_tsig_credentials *tc)
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{
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return tc->keydata;
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}
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char *
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ldns_tsig_keyname_clone(ldns_tsig_credentials *tc)
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{
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return strdup(tc->keyname);
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}
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char *
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ldns_tsig_keydata_clone(ldns_tsig_credentials *tc)
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{
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return strdup(tc->keydata);
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}
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/*
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* Makes an exact copy of the wire, but with the tsig rr removed
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*/
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static uint8_t *
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ldns_tsig_prepare_pkt_wire(uint8_t *wire, size_t wire_len, size_t *result_len)
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{
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uint8_t *wire2 = NULL;
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uint16_t qd_count;
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uint16_t an_count;
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uint16_t ns_count;
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uint16_t ar_count;
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ldns_rr *rr;
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size_t pos;
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uint16_t i;
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ldns_status status;
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if(wire_len < LDNS_HEADER_SIZE) {
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return NULL;
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}
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/* fake parse the wire */
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qd_count = LDNS_QDCOUNT(wire);
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an_count = LDNS_ANCOUNT(wire);
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ns_count = LDNS_NSCOUNT(wire);
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ar_count = LDNS_ARCOUNT(wire);
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if (ar_count > 0) {
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ar_count--;
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} else {
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return NULL;
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}
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pos = LDNS_HEADER_SIZE;
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for (i = 0; i < qd_count; i++) {
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status = ldns_wire2rr(&rr, wire, wire_len, &pos, LDNS_SECTION_QUESTION);
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if (status != LDNS_STATUS_OK) {
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return NULL;
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}
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ldns_rr_free(rr);
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}
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for (i = 0; i < an_count; i++) {
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status = ldns_wire2rr(&rr, wire, wire_len, &pos, LDNS_SECTION_ANSWER);
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if (status != LDNS_STATUS_OK) {
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return NULL;
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}
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ldns_rr_free(rr);
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}
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for (i = 0; i < ns_count; i++) {
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status = ldns_wire2rr(&rr, wire, wire_len, &pos, LDNS_SECTION_AUTHORITY);
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if (status != LDNS_STATUS_OK) {
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return NULL;
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}
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ldns_rr_free(rr);
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}
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for (i = 0; i < ar_count; i++) {
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status = ldns_wire2rr(&rr, wire, wire_len, &pos,
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LDNS_SECTION_ADDITIONAL);
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if (status != LDNS_STATUS_OK) {
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return NULL;
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}
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ldns_rr_free(rr);
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}
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*result_len = pos;
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wire2 = LDNS_XMALLOC(uint8_t, *result_len);
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if(!wire2) {
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return NULL;
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}
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memcpy(wire2, wire, *result_len);
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ldns_write_uint16(wire2 + LDNS_ARCOUNT_OFF, ar_count);
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return wire2;
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}
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#ifdef HAVE_SSL
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static const EVP_MD *
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ldns_digest_function(char *name)
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{
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/* these are the mandatory algorithms from RFC4635 */
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/* The optional algorithms are not yet implemented */
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if (strlen(name) == 12
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&& strncasecmp(name, "hmac-sha256.", 11) == 0) {
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#ifdef HAVE_EVP_SHA256
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return EVP_sha256();
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#else
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return NULL;
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#endif
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} else if (strlen(name) == 10
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&& strncasecmp(name, "hmac-sha1.", 9) == 0) {
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return EVP_sha1();
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} else if (strlen(name) == 25
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&& strncasecmp(name, "hmac-md5.sig-alg.reg.int.", 25)
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== 0) {
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return EVP_md5();
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} else {
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return NULL;
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}
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}
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#endif
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#ifdef HAVE_SSL
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static ldns_status
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ldns_tsig_mac_new(ldns_rdf **tsig_mac, uint8_t *pkt_wire, size_t pkt_wire_size,
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const char *key_data, ldns_rdf *key_name_rdf, ldns_rdf *fudge_rdf,
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ldns_rdf *algorithm_rdf, ldns_rdf *time_signed_rdf, ldns_rdf *error_rdf,
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ldns_rdf *other_data_rdf, ldns_rdf *orig_mac_rdf, int tsig_timers_only)
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{
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ldns_status status;
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char *wireformat;
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int wiresize;
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unsigned char *mac_bytes = NULL;
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unsigned char *key_bytes = NULL;
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int key_size;
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const EVP_MD *digester;
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char *algorithm_name = NULL;
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unsigned int md_len = EVP_MAX_MD_SIZE;
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ldns_rdf *result = NULL;
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ldns_buffer *data_buffer = NULL;
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ldns_rdf *canonical_key_name_rdf = NULL;
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ldns_rdf *canonical_algorithm_rdf = NULL;
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if (key_name_rdf == NULL || algorithm_rdf == NULL) {
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return LDNS_STATUS_NULL;
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}
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canonical_key_name_rdf = ldns_rdf_clone(key_name_rdf);
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canonical_algorithm_rdf = ldns_rdf_clone(algorithm_rdf);
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if (canonical_key_name_rdf == NULL
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|| canonical_algorithm_rdf == NULL) {
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return LDNS_STATUS_MEM_ERR;
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}
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/*
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* prepare the digestable information
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*/
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data_buffer = ldns_buffer_new(LDNS_MAX_PACKETLEN);
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if (!data_buffer) {
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status = LDNS_STATUS_MEM_ERR;
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goto clean;
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}
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/* if orig_mac is not NULL, add it too */
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if (orig_mac_rdf) {
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(void) ldns_rdf2buffer_wire(data_buffer, orig_mac_rdf);
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}
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ldns_buffer_write(data_buffer, pkt_wire, pkt_wire_size);
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if (!tsig_timers_only) {
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ldns_dname2canonical(canonical_key_name_rdf);
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(void)ldns_rdf2buffer_wire(data_buffer,
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canonical_key_name_rdf);
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ldns_buffer_write_u16(data_buffer, LDNS_RR_CLASS_ANY);
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ldns_buffer_write_u32(data_buffer, 0);
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ldns_dname2canonical(canonical_algorithm_rdf);
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(void)ldns_rdf2buffer_wire(data_buffer,
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canonical_algorithm_rdf);
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}
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(void)ldns_rdf2buffer_wire(data_buffer, time_signed_rdf);
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(void)ldns_rdf2buffer_wire(data_buffer, fudge_rdf);
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if (!tsig_timers_only) {
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(void)ldns_rdf2buffer_wire(data_buffer, error_rdf);
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(void)ldns_rdf2buffer_wire(data_buffer, other_data_rdf);
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}
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wireformat = (char *) data_buffer->_data;
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wiresize = (int) ldns_buffer_position(data_buffer);
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algorithm_name = ldns_rdf2str(algorithm_rdf);
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if(!algorithm_name) {
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status = LDNS_STATUS_MEM_ERR;
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goto clean;
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}
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/* prepare the key */
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key_bytes = LDNS_XMALLOC(unsigned char,
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ldns_b64_pton_calculate_size(strlen(key_data)));
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if(!key_bytes) {
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status = LDNS_STATUS_MEM_ERR;
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goto clean;
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}
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key_size = ldns_b64_pton(key_data, key_bytes,
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ldns_b64_pton_calculate_size(strlen(key_data)));
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if (key_size < 0) {
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status = LDNS_STATUS_INVALID_B64;
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goto clean;
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}
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/* hmac it */
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/* 2 spare bytes for the length */
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mac_bytes = LDNS_XMALLOC(unsigned char, md_len+2);
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if(!mac_bytes) {
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status = LDNS_STATUS_MEM_ERR;
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goto clean;
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}
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memset(mac_bytes, 0, md_len+2);
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digester = ldns_digest_function(algorithm_name);
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if (digester) {
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(void) HMAC(digester, key_bytes, key_size, (void *)wireformat,
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(size_t) wiresize, mac_bytes + 2, &md_len);
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ldns_write_uint16(mac_bytes, md_len);
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result = ldns_rdf_new_frm_data(LDNS_RDF_TYPE_INT16_DATA, md_len + 2,
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mac_bytes);
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} else {
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status = LDNS_STATUS_CRYPTO_UNKNOWN_ALGO;
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goto clean;
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}
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*tsig_mac = result;
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status = LDNS_STATUS_OK;
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clean:
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LDNS_FREE(mac_bytes);
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LDNS_FREE(key_bytes);
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LDNS_FREE(algorithm_name);
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ldns_buffer_free(data_buffer);
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ldns_rdf_free(canonical_algorithm_rdf);
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ldns_rdf_free(canonical_key_name_rdf);
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return status;
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}
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#endif /* HAVE_SSL */
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#ifdef HAVE_SSL
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bool
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ldns_pkt_tsig_verify(ldns_pkt *pkt, uint8_t *wire, size_t wirelen, const char *key_name,
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const char *key_data, ldns_rdf *orig_mac_rdf)
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{
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return ldns_pkt_tsig_verify_next(pkt, wire, wirelen, key_name, key_data, orig_mac_rdf, 0);
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}
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bool
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ldns_pkt_tsig_verify_next(ldns_pkt *pkt, uint8_t *wire, size_t wirelen, const char* key_name,
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const char *key_data, ldns_rdf *orig_mac_rdf, int tsig_timers_only)
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{
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ldns_rdf *fudge_rdf;
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ldns_rdf *algorithm_rdf;
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ldns_rdf *time_signed_rdf;
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ldns_rdf *orig_id_rdf;
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ldns_rdf *error_rdf;
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ldns_rdf *other_data_rdf;
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ldns_rdf *pkt_mac_rdf;
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ldns_rdf *my_mac_rdf;
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ldns_rdf *key_name_rdf = ldns_rdf_new_frm_str(LDNS_RDF_TYPE_DNAME, key_name);
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uint16_t pkt_id, orig_pkt_id;
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ldns_status status;
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uint8_t *prepared_wire = NULL;
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size_t prepared_wire_size = 0;
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ldns_rr *orig_tsig = ldns_pkt_tsig(pkt);
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if (!orig_tsig || ldns_rr_rd_count(orig_tsig) <= 6) {
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ldns_rdf_deep_free(key_name_rdf);
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return false;
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}
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algorithm_rdf = ldns_rr_rdf(orig_tsig, 0);
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time_signed_rdf = ldns_rr_rdf(orig_tsig, 1);
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fudge_rdf = ldns_rr_rdf(orig_tsig, 2);
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pkt_mac_rdf = ldns_rr_rdf(orig_tsig, 3);
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orig_id_rdf = ldns_rr_rdf(orig_tsig, 4);
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error_rdf = ldns_rr_rdf(orig_tsig, 5);
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other_data_rdf = ldns_rr_rdf(orig_tsig, 6);
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/* remove temporarily */
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ldns_pkt_set_tsig(pkt, NULL);
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/* temporarily change the id to the original id */
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pkt_id = ldns_pkt_id(pkt);
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orig_pkt_id = ldns_rdf2native_int16(orig_id_rdf);
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ldns_pkt_set_id(pkt, orig_pkt_id);
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prepared_wire = ldns_tsig_prepare_pkt_wire(wire, wirelen, &prepared_wire_size);
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status = ldns_tsig_mac_new(&my_mac_rdf, prepared_wire, prepared_wire_size,
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key_data, key_name_rdf, fudge_rdf, algorithm_rdf,
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time_signed_rdf, error_rdf, other_data_rdf, orig_mac_rdf, tsig_timers_only);
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LDNS_FREE(prepared_wire);
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if (status != LDNS_STATUS_OK) {
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ldns_rdf_deep_free(key_name_rdf);
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return false;
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}
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/* Put back the values */
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ldns_pkt_set_tsig(pkt, orig_tsig);
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ldns_pkt_set_id(pkt, pkt_id);
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ldns_rdf_deep_free(key_name_rdf);
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if (ldns_rdf_compare(pkt_mac_rdf, my_mac_rdf) == 0) {
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ldns_rdf_deep_free(my_mac_rdf);
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return true;
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} else {
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ldns_rdf_deep_free(my_mac_rdf);
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return false;
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}
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}
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#endif /* HAVE_SSL */
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#ifdef HAVE_SSL
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ldns_status
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ldns_pkt_tsig_sign(ldns_pkt *pkt, const char *key_name, const char *key_data,
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uint16_t fudge, const char *algorithm_name, ldns_rdf *query_mac)
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{
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return ldns_pkt_tsig_sign_next(pkt, key_name, key_data, fudge, algorithm_name, query_mac, 0);
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}
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ldns_status
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ldns_pkt_tsig_sign_next(ldns_pkt *pkt, const char *key_name, const char *key_data,
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uint16_t fudge, const char *algorithm_name, ldns_rdf *query_mac, int tsig_timers_only)
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{
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ldns_rr *tsig_rr;
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ldns_rdf *key_name_rdf = ldns_rdf_new_frm_str(LDNS_RDF_TYPE_DNAME, key_name);
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ldns_rdf *fudge_rdf = NULL;
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ldns_rdf *orig_id_rdf = NULL;
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ldns_rdf *algorithm_rdf;
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ldns_rdf *error_rdf = NULL;
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ldns_rdf *mac_rdf = NULL;
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ldns_rdf *other_data_rdf = NULL;
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ldns_status status = LDNS_STATUS_OK;
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uint8_t *pkt_wire = NULL;
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size_t pkt_wire_len;
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struct timeval tv_time_signed;
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uint8_t *time_signed = NULL;
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ldns_rdf *time_signed_rdf = NULL;
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algorithm_rdf = ldns_rdf_new_frm_str(LDNS_RDF_TYPE_DNAME, algorithm_name);
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if(!key_name_rdf || !algorithm_rdf) {
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status = LDNS_STATUS_MEM_ERR;
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goto clean;
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}
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/* eww don't have create tsigtime rdf yet :( */
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/* bleh :p */
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if (gettimeofday(&tv_time_signed, NULL) == 0) {
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time_signed = LDNS_XMALLOC(uint8_t, 6);
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if(!time_signed) {
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status = LDNS_STATUS_MEM_ERR;
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goto clean;
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}
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ldns_write_uint64_as_uint48(time_signed,
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(uint64_t)tv_time_signed.tv_sec);
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} else {
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status = LDNS_STATUS_INTERNAL_ERR;
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goto clean;
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}
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time_signed_rdf = ldns_rdf_new(LDNS_RDF_TYPE_TSIGTIME, 6, time_signed);
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if(!time_signed_rdf) {
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LDNS_FREE(time_signed);
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status = LDNS_STATUS_MEM_ERR;
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goto clean;
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}
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fudge_rdf = ldns_native2rdf_int16(LDNS_RDF_TYPE_INT16, fudge);
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orig_id_rdf = ldns_native2rdf_int16(LDNS_RDF_TYPE_INT16, ldns_pkt_id(pkt));
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error_rdf = ldns_native2rdf_int16(LDNS_RDF_TYPE_INT16, 0);
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other_data_rdf = ldns_native2rdf_int16_data(0, NULL);
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if(!fudge_rdf || !orig_id_rdf || !error_rdf || !other_data_rdf) {
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status = LDNS_STATUS_MEM_ERR;
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goto clean;
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}
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if (ldns_pkt2wire(&pkt_wire, pkt, &pkt_wire_len) != LDNS_STATUS_OK) {
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status = LDNS_STATUS_ERR;
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goto clean;
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}
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status = ldns_tsig_mac_new(&mac_rdf, pkt_wire, pkt_wire_len,
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key_data, key_name_rdf, fudge_rdf, algorithm_rdf,
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time_signed_rdf, error_rdf, other_data_rdf, query_mac, tsig_timers_only);
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if (!mac_rdf) {
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goto clean;
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}
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LDNS_FREE(pkt_wire);
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/* Create the TSIG RR */
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tsig_rr = ldns_rr_new();
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if(!tsig_rr) {
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status = LDNS_STATUS_MEM_ERR;
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goto clean;
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}
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ldns_rr_set_owner(tsig_rr, key_name_rdf);
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ldns_rr_set_class(tsig_rr, LDNS_RR_CLASS_ANY);
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ldns_rr_set_type(tsig_rr, LDNS_RR_TYPE_TSIG);
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ldns_rr_set_ttl(tsig_rr, 0);
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ldns_rr_push_rdf(tsig_rr, algorithm_rdf);
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ldns_rr_push_rdf(tsig_rr, time_signed_rdf);
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ldns_rr_push_rdf(tsig_rr, fudge_rdf);
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ldns_rr_push_rdf(tsig_rr, mac_rdf);
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ldns_rr_push_rdf(tsig_rr, orig_id_rdf);
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ldns_rr_push_rdf(tsig_rr, error_rdf);
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ldns_rr_push_rdf(tsig_rr, other_data_rdf);
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ldns_pkt_set_tsig(pkt, tsig_rr);
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return status;
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clean:
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LDNS_FREE(pkt_wire);
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ldns_rdf_free(key_name_rdf);
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ldns_rdf_free(algorithm_rdf);
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ldns_rdf_free(time_signed_rdf);
|
|
ldns_rdf_free(fudge_rdf);
|
|
ldns_rdf_free(orig_id_rdf);
|
|
ldns_rdf_free(error_rdf);
|
|
ldns_rdf_free(other_data_rdf);
|
|
return status;
|
|
}
|
|
#endif /* HAVE_SSL */
|