freebsd-dev/contrib/ldns/tsig.c
Dag-Erling Smørgrav 2787e39aaa Upgrade to 1.6.16
2013-02-15 21:49:12 +00:00

475 lines
12 KiB
C

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