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monero/external/unbound/validator/val_sigcrypt.c

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/*
* validator/val_sigcrypt.c - validator signature crypto functions.
*
* Copyright (c) 2007, NLnet Labs. All rights reserved.
*
* This software is open source.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of the NLNET LABS nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* \file
*
* This file contains helper functions for the validator module.
* The functions help with signature verification and checking, the
* bridging between RR wireformat data and crypto calls.
*/
#include "config.h"
#include "validator/val_sigcrypt.h"
#include "validator/val_secalgo.h"
#include "validator/validator.h"
#include "util/data/msgreply.h"
#include "util/data/msgparse.h"
#include "util/data/dname.h"
#include "util/rbtree.h"
#include "util/module.h"
#include "util/net_help.h"
#include "util/regional.h"
#include "sldns/keyraw.h"
#include "sldns/sbuffer.h"
#include "sldns/parseutil.h"
#include "sldns/wire2str.h"
#include <ctype.h>
#if !defined(HAVE_SSL) && !defined(HAVE_NSS) && !defined(HAVE_NETTLE)
#error "Need crypto library to do digital signature cryptography"
#endif
#ifdef HAVE_OPENSSL_ERR_H
#include <openssl/err.h>
#endif
#ifdef HAVE_OPENSSL_RAND_H
#include <openssl/rand.h>
#endif
#ifdef HAVE_OPENSSL_CONF_H
#include <openssl/conf.h>
#endif
#ifdef HAVE_OPENSSL_ENGINE_H
#include <openssl/engine.h>
#endif
/** return number of rrs in an rrset */
static size_t
rrset_get_count(struct ub_packed_rrset_key* rrset)
{
struct packed_rrset_data* d = (struct packed_rrset_data*)
rrset->entry.data;
if(!d) return 0;
return d->count;
}
/**
* Get RR signature count
*/
static size_t
rrset_get_sigcount(struct ub_packed_rrset_key* k)
{
struct packed_rrset_data* d = (struct packed_rrset_data*)k->entry.data;
return d->rrsig_count;
}
/**
* Get signature keytag value
* @param k: rrset (with signatures)
* @param sig_idx: signature index.
* @return keytag or 0 if malformed rrsig.
*/
static uint16_t
rrset_get_sig_keytag(struct ub_packed_rrset_key* k, size_t sig_idx)
{
uint16_t t;
struct packed_rrset_data* d = (struct packed_rrset_data*)k->entry.data;
log_assert(sig_idx < d->rrsig_count);
if(d->rr_len[d->count + sig_idx] < 2+18)
return 0;
memmove(&t, d->rr_data[d->count + sig_idx]+2+16, 2);
return ntohs(t);
}
/**
* Get signature signing algorithm value
* @param k: rrset (with signatures)
* @param sig_idx: signature index.
* @return algo or 0 if malformed rrsig.
*/
static int
rrset_get_sig_algo(struct ub_packed_rrset_key* k, size_t sig_idx)
{
struct packed_rrset_data* d = (struct packed_rrset_data*)k->entry.data;
log_assert(sig_idx < d->rrsig_count);
if(d->rr_len[d->count + sig_idx] < 2+3)
return 0;
return (int)d->rr_data[d->count + sig_idx][2+2];
}
/** get rdata pointer and size */
static void
rrset_get_rdata(struct ub_packed_rrset_key* k, size_t idx, uint8_t** rdata,
size_t* len)
{
struct packed_rrset_data* d = (struct packed_rrset_data*)k->entry.data;
log_assert(d && idx < (d->count + d->rrsig_count));
*rdata = d->rr_data[idx];
*len = d->rr_len[idx];
}
uint16_t
dnskey_get_flags(struct ub_packed_rrset_key* k, size_t idx)
{
uint8_t* rdata;
size_t len;
uint16_t f;
rrset_get_rdata(k, idx, &rdata, &len);
if(len < 2+2)
return 0;
memmove(&f, rdata+2, 2);
f = ntohs(f);
return f;
}
/**
* Get DNSKEY protocol value from rdata
* @param k: DNSKEY rrset.
* @param idx: which key.
* @return protocol octet value
*/
static int
dnskey_get_protocol(struct ub_packed_rrset_key* k, size_t idx)
{
uint8_t* rdata;
size_t len;
rrset_get_rdata(k, idx, &rdata, &len);
if(len < 2+4)
return 0;
return (int)rdata[2+2];
}
int
dnskey_get_algo(struct ub_packed_rrset_key* k, size_t idx)
{
uint8_t* rdata;
size_t len;
rrset_get_rdata(k, idx, &rdata, &len);
if(len < 2+4)
return 0;
return (int)rdata[2+3];
}
/** get public key rdata field from a dnskey RR and do some checks */
static void
dnskey_get_pubkey(struct ub_packed_rrset_key* k, size_t idx,
unsigned char** pk, unsigned int* pklen)
{
uint8_t* rdata;
size_t len;
rrset_get_rdata(k, idx, &rdata, &len);
if(len < 2+5) {
*pk = NULL;
*pklen = 0;
return;
}
*pk = (unsigned char*)rdata+2+4;
*pklen = (unsigned)len-2-4;
}
int
ds_get_key_algo(struct ub_packed_rrset_key* k, size_t idx)
{
uint8_t* rdata;
size_t len;
rrset_get_rdata(k, idx, &rdata, &len);
if(len < 2+3)
return 0;
return (int)rdata[2+2];
}
int
ds_get_digest_algo(struct ub_packed_rrset_key* k, size_t idx)
{
uint8_t* rdata;
size_t len;
rrset_get_rdata(k, idx, &rdata, &len);
if(len < 2+4)
return 0;
return (int)rdata[2+3];
}
uint16_t
ds_get_keytag(struct ub_packed_rrset_key* ds_rrset, size_t ds_idx)
{
uint16_t t;
uint8_t* rdata;
size_t len;
rrset_get_rdata(ds_rrset, ds_idx, &rdata, &len);
if(len < 2+2)
return 0;
memmove(&t, rdata+2, 2);
return ntohs(t);
}
/**
* Return pointer to the digest in a DS RR.
* @param k: DS rrset.
* @param idx: which DS.
* @param digest: digest data is returned.
* on error, this is NULL.
* @param len: length of digest is returned.
* on error, the length is 0.
*/
static void
ds_get_sigdata(struct ub_packed_rrset_key* k, size_t idx, uint8_t** digest,
size_t* len)
{
uint8_t* rdata;
size_t rdlen;
rrset_get_rdata(k, idx, &rdata, &rdlen);
if(rdlen < 2+5) {
*digest = NULL;
*len = 0;
return;
}
*digest = rdata + 2 + 4;
*len = rdlen - 2 - 4;
}
/**
* Return size of DS digest according to its hash algorithm.
* @param k: DS rrset.
* @param idx: which DS.
* @return size in bytes of digest, or 0 if not supported.
*/
static size_t
ds_digest_size_algo(struct ub_packed_rrset_key* k, size_t idx)
{
return ds_digest_size_supported(ds_get_digest_algo(k, idx));
}
/**
* Create a DS digest for a DNSKEY entry.
*
* @param env: module environment. Uses scratch space.
* @param dnskey_rrset: DNSKEY rrset.
* @param dnskey_idx: index of RR in rrset.
* @param ds_rrset: DS rrset
* @param ds_idx: index of RR in DS rrset.
* @param digest: digest is returned in here (must be correctly sized).
* @return false on error.
*/
static int
ds_create_dnskey_digest(struct module_env* env,
struct ub_packed_rrset_key* dnskey_rrset, size_t dnskey_idx,
struct ub_packed_rrset_key* ds_rrset, size_t ds_idx,
uint8_t* digest)
{
sldns_buffer* b = env->scratch_buffer;
uint8_t* dnskey_rdata;
size_t dnskey_len;
rrset_get_rdata(dnskey_rrset, dnskey_idx, &dnskey_rdata, &dnskey_len);
/* create digest source material in buffer
* digest = digest_algorithm( DNSKEY owner name | DNSKEY RDATA);
* DNSKEY RDATA = Flags | Protocol | Algorithm | Public Key. */
sldns_buffer_clear(b);
sldns_buffer_write(b, dnskey_rrset->rk.dname,
dnskey_rrset->rk.dname_len);
query_dname_tolower(sldns_buffer_begin(b));
sldns_buffer_write(b, dnskey_rdata+2, dnskey_len-2); /* skip rdatalen*/
sldns_buffer_flip(b);
return secalgo_ds_digest(ds_get_digest_algo(ds_rrset, ds_idx),
(unsigned char*)sldns_buffer_begin(b), sldns_buffer_limit(b),
(unsigned char*)digest);
}
int ds_digest_match_dnskey(struct module_env* env,
struct ub_packed_rrset_key* dnskey_rrset, size_t dnskey_idx,
struct ub_packed_rrset_key* ds_rrset, size_t ds_idx)
{
uint8_t* ds; /* DS digest */
size_t dslen;
uint8_t* digest; /* generated digest */
size_t digestlen = ds_digest_size_algo(ds_rrset, ds_idx);
if(digestlen == 0) {
verbose(VERB_QUERY, "DS fail: not supported, or DS RR "
"format error");
return 0; /* not supported, or DS RR format error */
}
/* check digest length in DS with length from hash function */
ds_get_sigdata(ds_rrset, ds_idx, &ds, &dslen);
if(!ds || dslen != digestlen) {
verbose(VERB_QUERY, "DS fail: DS RR algo and digest do not "
"match each other");
return 0; /* DS algorithm and digest do not match */
}
digest = regional_alloc(env->scratch, digestlen);
if(!digest) {
verbose(VERB_QUERY, "DS fail: out of memory");
return 0; /* mem error */
}
if(!ds_create_dnskey_digest(env, dnskey_rrset, dnskey_idx, ds_rrset,
ds_idx, digest)) {
verbose(VERB_QUERY, "DS fail: could not calc key digest");
return 0; /* digest algo failed */
}
if(memcmp(digest, ds, dslen) != 0) {
verbose(VERB_QUERY, "DS fail: digest is different");
return 0; /* digest different */
}
return 1;
}
int
ds_digest_algo_is_supported(struct ub_packed_rrset_key* ds_rrset,
size_t ds_idx)
{
return (ds_digest_size_algo(ds_rrset, ds_idx) != 0);
}
int
ds_key_algo_is_supported(struct ub_packed_rrset_key* ds_rrset,
size_t ds_idx)
{
return dnskey_algo_id_is_supported(ds_get_key_algo(ds_rrset, ds_idx));
}
uint16_t
dnskey_calc_keytag(struct ub_packed_rrset_key* dnskey_rrset, size_t dnskey_idx)
{
uint8_t* data;
size_t len;
rrset_get_rdata(dnskey_rrset, dnskey_idx, &data, &len);
/* do not pass rdatalen to ldns */
return sldns_calc_keytag_raw(data+2, len-2);
}
int dnskey_algo_is_supported(struct ub_packed_rrset_key* dnskey_rrset,
size_t dnskey_idx)
{
return dnskey_algo_id_is_supported(dnskey_get_algo(dnskey_rrset,
dnskey_idx));
}
void algo_needs_init_dnskey_add(struct algo_needs* n,
struct ub_packed_rrset_key* dnskey, uint8_t* sigalg)
{
uint8_t algo;
size_t i, total = n->num;
size_t num = rrset_get_count(dnskey);
for(i=0; i<num; i++) {
algo = (uint8_t)dnskey_get_algo(dnskey, i);
if(!dnskey_algo_id_is_supported((int)algo))
continue;
if(n->needs[algo] == 0) {
n->needs[algo] = 1;
sigalg[total] = algo;
total++;
}
}
sigalg[total] = 0;
n->num = total;
}
void algo_needs_init_list(struct algo_needs* n, uint8_t* sigalg)
{
uint8_t algo;
size_t total = 0;
memset(n->needs, 0, sizeof(uint8_t)*ALGO_NEEDS_MAX);
while( (algo=*sigalg++) != 0) {
log_assert(dnskey_algo_id_is_supported((int)algo));
log_assert(n->needs[algo] == 0);
n->needs[algo] = 1;
total++;
}
n->num = total;
}
void algo_needs_init_ds(struct algo_needs* n, struct ub_packed_rrset_key* ds,
int fav_ds_algo, uint8_t* sigalg)
{
uint8_t algo;
size_t i, total = 0;
size_t num = rrset_get_count(ds);
memset(n->needs, 0, sizeof(uint8_t)*ALGO_NEEDS_MAX);
for(i=0; i<num; i++) {
if(ds_get_digest_algo(ds, i) != fav_ds_algo)
continue;
algo = (uint8_t)ds_get_key_algo(ds, i);
if(!dnskey_algo_id_is_supported((int)algo))
continue;
log_assert(algo != 0); /* we do not support 0 and is EOS */
if(n->needs[algo] == 0) {
n->needs[algo] = 1;
sigalg[total] = algo;
total++;
}
}
sigalg[total] = 0;
n->num = total;
}
int algo_needs_set_secure(struct algo_needs* n, uint8_t algo)
{
if(n->needs[algo]) {
n->needs[algo] = 0;
n->num --;
if(n->num == 0) /* done! */
return 1;
}
return 0;
}
void algo_needs_set_bogus(struct algo_needs* n, uint8_t algo)
{
if(n->needs[algo]) n->needs[algo] = 2; /* need it, but bogus */
}
size_t algo_needs_num_missing(struct algo_needs* n)
{
return n->num;
}
int algo_needs_missing(struct algo_needs* n)
{
int i;
/* first check if a needed algo was bogus - report that */
for(i=0; i<ALGO_NEEDS_MAX; i++)
if(n->needs[i] == 2)
return 0;
/* now check which algo is missing */
for(i=0; i<ALGO_NEEDS_MAX; i++)
if(n->needs[i] == 1)
return i;
return 0;
}
enum sec_status
dnskeyset_verify_rrset(struct module_env* env, struct val_env* ve,
struct ub_packed_rrset_key* rrset, struct ub_packed_rrset_key* dnskey,
uint8_t* sigalg, char** reason)
{
enum sec_status sec;
size_t i, num;
rbtree_t* sortree = NULL;
/* make sure that for all DNSKEY algorithms there are valid sigs */
struct algo_needs needs;
int alg;
num = rrset_get_sigcount(rrset);
if(num == 0) {
verbose(VERB_QUERY, "rrset failed to verify due to a lack of "
"signatures");
*reason = "no signatures";
return sec_status_bogus;
}
if(sigalg) {
algo_needs_init_list(&needs, sigalg);
if(algo_needs_num_missing(&needs) == 0) {
verbose(VERB_QUERY, "zone has no known algorithms");
*reason = "zone has no known algorithms";
return sec_status_insecure;
}
}
for(i=0; i<num; i++) {
sec = dnskeyset_verify_rrset_sig(env, ve, *env->now, rrset,
dnskey, i, &sortree, reason);
/* see which algorithm has been fixed up */
if(sec == sec_status_secure) {
if(!sigalg)
return sec; /* done! */
else if(algo_needs_set_secure(&needs,
(uint8_t)rrset_get_sig_algo(rrset, i)))
return sec; /* done! */
} else if(sigalg && sec == sec_status_bogus) {
algo_needs_set_bogus(&needs,
(uint8_t)rrset_get_sig_algo(rrset, i));
}
}
if(sigalg && (alg=algo_needs_missing(&needs)) != 0) {
verbose(VERB_ALGO, "rrset failed to verify: "
"no valid signatures for %d algorithms",
(int)algo_needs_num_missing(&needs));
algo_needs_reason(env, alg, reason, "no signatures");
} else {
verbose(VERB_ALGO, "rrset failed to verify: "
"no valid signatures");
}
return sec_status_bogus;
}
void algo_needs_reason(struct module_env* env, int alg, char** reason, char* s)
{
char buf[256];
sldns_lookup_table *t = sldns_lookup_by_id(sldns_algorithms, alg);
if(t&&t->name)
snprintf(buf, sizeof(buf), "%s with algorithm %s", s, t->name);
else snprintf(buf, sizeof(buf), "%s with algorithm ALG%u", s,
(unsigned)alg);
*reason = regional_strdup(env->scratch, buf);
if(!*reason)
*reason = s;
}
enum sec_status
dnskey_verify_rrset(struct module_env* env, struct val_env* ve,
struct ub_packed_rrset_key* rrset, struct ub_packed_rrset_key* dnskey,
size_t dnskey_idx, char** reason)
{
enum sec_status sec;
size_t i, num, numchecked = 0;
rbtree_t* sortree = NULL;
int buf_canon = 0;
uint16_t tag = dnskey_calc_keytag(dnskey, dnskey_idx);
int algo = dnskey_get_algo(dnskey, dnskey_idx);
num = rrset_get_sigcount(rrset);
if(num == 0) {
verbose(VERB_QUERY, "rrset failed to verify due to a lack of "
"signatures");
*reason = "no signatures";
return sec_status_bogus;
}
for(i=0; i<num; i++) {
/* see if sig matches keytag and algo */
if(algo != rrset_get_sig_algo(rrset, i) ||
tag != rrset_get_sig_keytag(rrset, i))
continue;
buf_canon = 0;
sec = dnskey_verify_rrset_sig(env->scratch,
env->scratch_buffer, ve, *env->now, rrset,
dnskey, dnskey_idx, i, &sortree, &buf_canon, reason);
if(sec == sec_status_secure)
return sec;
numchecked ++;
}
verbose(VERB_ALGO, "rrset failed to verify: all signatures are bogus");
if(!numchecked) *reason = "signature missing";
return sec_status_bogus;
}
enum sec_status
dnskeyset_verify_rrset_sig(struct module_env* env, struct val_env* ve,
time_t now, struct ub_packed_rrset_key* rrset,
struct ub_packed_rrset_key* dnskey, size_t sig_idx,
struct rbtree_t** sortree, char** reason)
{
/* find matching keys and check them */
enum sec_status sec = sec_status_bogus;
uint16_t tag = rrset_get_sig_keytag(rrset, sig_idx);
int algo = rrset_get_sig_algo(rrset, sig_idx);
size_t i, num = rrset_get_count(dnskey);
size_t numchecked = 0;
int buf_canon = 0;
verbose(VERB_ALGO, "verify sig %d %d", (int)tag, algo);
if(!dnskey_algo_id_is_supported(algo)) {
verbose(VERB_QUERY, "verify sig: unknown algorithm");
return sec_status_insecure;
}
for(i=0; i<num; i++) {
/* see if key matches keytag and algo */
if(algo != dnskey_get_algo(dnskey, i) ||
tag != dnskey_calc_keytag(dnskey, i))
continue;
numchecked ++;
/* see if key verifies */
sec = dnskey_verify_rrset_sig(env->scratch,
env->scratch_buffer, ve, now, rrset, dnskey, i,
sig_idx, sortree, &buf_canon, reason);
if(sec == sec_status_secure)
return sec;
}
if(numchecked == 0) {
*reason = "signatures from unknown keys";
verbose(VERB_QUERY, "verify: could not find appropriate key");
return sec_status_bogus;
}
return sec_status_bogus;
}
/**
* RR entries in a canonical sorted tree of RRs
*/
struct canon_rr {
/** rbtree node, key is this structure */
rbnode_t node;
/** rrset the RR is in */
struct ub_packed_rrset_key* rrset;
/** which RR in the rrset */
size_t rr_idx;
};
/**
* Compare two RR for canonical order, in a field-style sweep.
* @param d: rrset data
* @param desc: ldns wireformat descriptor.
* @param i: first RR to compare
* @param j: first RR to compare
* @return comparison code.
*/
static int
canonical_compare_byfield(struct packed_rrset_data* d,
const sldns_rr_descriptor* desc, size_t i, size_t j)
{
/* sweep across rdata, keep track of some state:
* which rr field, and bytes left in field.
* current position in rdata, length left.
* are we in a dname, length left in a label.
*/
int wfi = -1; /* current wireformat rdata field (rdf) */
int wfj = -1;
uint8_t* di = d->rr_data[i]+2; /* ptr to current rdata byte */
uint8_t* dj = d->rr_data[j]+2;
size_t ilen = d->rr_len[i]-2; /* length left in rdata */
size_t jlen = d->rr_len[j]-2;
int dname_i = 0; /* true if these bytes are part of a name */
int dname_j = 0;
size_t lablen_i = 0; /* 0 for label length byte,for first byte of rdf*/
size_t lablen_j = 0; /* otherwise remaining length of rdf or label */
int dname_num_i = (int)desc->_dname_count; /* decreased at root label */
int dname_num_j = (int)desc->_dname_count;
/* loop while there are rdata bytes available for both rrs,
* and still some lowercasing needs to be done; either the dnames
* have not been reached yet, or they are currently being processed */
while(ilen > 0 && jlen > 0 && (dname_num_i > 0 || dname_num_j > 0)) {
/* compare these two bytes */
/* lowercase if in a dname and not a label length byte */
if( ((dname_i && lablen_i)?(uint8_t)tolower((int)*di):*di)
!= ((dname_j && lablen_j)?(uint8_t)tolower((int)*dj):*dj)
) {
if(((dname_i && lablen_i)?(uint8_t)tolower((int)*di):*di)
< ((dname_j && lablen_j)?(uint8_t)tolower((int)*dj):*dj))
return -1;
return 1;
}
ilen--;
jlen--;
/* bytes are equal */
/* advance field i */
/* lablen 0 means that this byte is the first byte of the
* next rdata field; inspect this rdata field and setup
* to process the rest of this rdata field.
* The reason to first read the byte, then setup the rdf,
* is that we are then sure the byte is available and short
* rdata is handled gracefully (even if it is a formerr). */
if(lablen_i == 0) {
if(dname_i) {
/* scan this dname label */
/* capture length to lowercase */
lablen_i = (size_t)*di;
if(lablen_i == 0) {
/* end root label */
dname_i = 0;
dname_num_i--;
/* if dname num is 0, then the
* remainder is binary only */
if(dname_num_i == 0)
lablen_i = ilen;
}
} else {
/* scan this rdata field */
wfi++;
if(desc->_wireformat[wfi]
== LDNS_RDF_TYPE_DNAME) {
dname_i = 1;
lablen_i = (size_t)*di;
if(lablen_i == 0) {
dname_i = 0;
dname_num_i--;
if(dname_num_i == 0)
lablen_i = ilen;
}
} else if(desc->_wireformat[wfi]
== LDNS_RDF_TYPE_STR)
lablen_i = (size_t)*di;
else lablen_i = get_rdf_size(
desc->_wireformat[wfi]) - 1;
}
} else lablen_i--;
/* advance field j; same as for i */
if(lablen_j == 0) {
if(dname_j) {
lablen_j = (size_t)*dj;
if(lablen_j == 0) {
dname_j = 0;
dname_num_j--;
if(dname_num_j == 0)
lablen_j = jlen;
}
} else {
wfj++;
if(desc->_wireformat[wfj]
== LDNS_RDF_TYPE_DNAME) {
dname_j = 1;
lablen_j = (size_t)*dj;
if(lablen_j == 0) {
dname_j = 0;
dname_num_j--;
if(dname_num_j == 0)
lablen_j = jlen;
}
} else if(desc->_wireformat[wfj]
== LDNS_RDF_TYPE_STR)
lablen_j = (size_t)*dj;
else lablen_j = get_rdf_size(
desc->_wireformat[wfj]) - 1;
}
} else lablen_j--;
di++;
dj++;
}
/* end of the loop; because we advanced byte by byte; now we have
* that the rdata has ended, or that there is a binary remainder */
/* shortest first */
if(ilen == 0 && jlen == 0)
return 0;
if(ilen == 0)
return -1;
if(jlen == 0)
return 1;
/* binary remainder, capture comparison in wfi variable */
if((wfi = memcmp(di, dj, (ilen<jlen)?ilen:jlen)) != 0)
return wfi;
if(ilen < jlen)
return -1;
if(jlen < ilen)
return 1;
return 0;
}
/**
* Compare two RRs in the same RRset and determine their relative
* canonical order.
* @param rrset: the rrset in which to perform compares.
* @param i: first RR to compare
* @param j: first RR to compare
* @return 0 if RR i== RR j, -1 if <, +1 if >.
*/
static int
canonical_compare(struct ub_packed_rrset_key* rrset, size_t i, size_t j)
{
struct packed_rrset_data* d = (struct packed_rrset_data*)
rrset->entry.data;
const sldns_rr_descriptor* desc;
uint16_t type = ntohs(rrset->rk.type);
size_t minlen;
int c;
if(i==j)
return 0;
switch(type) {
/* These RR types have only a name as RDATA.
* This name has to be canonicalized.*/
case LDNS_RR_TYPE_NS:
case LDNS_RR_TYPE_MD:
case LDNS_RR_TYPE_MF:
case LDNS_RR_TYPE_CNAME:
case LDNS_RR_TYPE_MB:
case LDNS_RR_TYPE_MG:
case LDNS_RR_TYPE_MR:
case LDNS_RR_TYPE_PTR:
case LDNS_RR_TYPE_DNAME:
/* the wireread function has already checked these
* dname's for correctness, and this double checks */
if(!dname_valid(d->rr_data[i]+2, d->rr_len[i]-2) ||
!dname_valid(d->rr_data[j]+2, d->rr_len[j]-2))
return 0;
return query_dname_compare(d->rr_data[i]+2,
d->rr_data[j]+2);
/* These RR types have STR and fixed size rdata fields
* before one or more name fields that need canonicalizing,
* and after that a byte-for byte remainder can be compared.
*/
/* type starts with the name; remainder is binary compared */
case LDNS_RR_TYPE_NXT:
/* use rdata field formats */
case LDNS_RR_TYPE_MINFO:
case LDNS_RR_TYPE_RP:
case LDNS_RR_TYPE_SOA:
case LDNS_RR_TYPE_RT:
case LDNS_RR_TYPE_AFSDB:
case LDNS_RR_TYPE_KX:
case LDNS_RR_TYPE_MX:
case LDNS_RR_TYPE_SIG:
/* RRSIG signer name has to be downcased */
case LDNS_RR_TYPE_RRSIG:
case LDNS_RR_TYPE_PX:
case LDNS_RR_TYPE_NAPTR:
case LDNS_RR_TYPE_SRV:
desc = sldns_rr_descript(type);
log_assert(desc);
/* this holds for the types that need canonicalizing */
log_assert(desc->_minimum == desc->_maximum);
return canonical_compare_byfield(d, desc, i, j);
case LDNS_RR_TYPE_HINFO: /* no longer downcased */
case LDNS_RR_TYPE_NSEC:
default:
/* For unknown RR types, or types not listed above,
* no canonicalization is needed, do binary compare */
/* byte for byte compare, equal means shortest first*/
minlen = d->rr_len[i]-2;
if(minlen > d->rr_len[j]-2)
minlen = d->rr_len[j]-2;
c = memcmp(d->rr_data[i]+2, d->rr_data[j]+2, minlen);
if(c!=0)
return c;
/* rdata equal, shortest is first */
if(d->rr_len[i] < d->rr_len[j])
return -1;
if(d->rr_len[i] > d->rr_len[j])
return 1;
/* rdata equal, length equal */
break;
}
return 0;
}
int
canonical_tree_compare(const void* k1, const void* k2)
{
struct canon_rr* r1 = (struct canon_rr*)k1;
struct canon_rr* r2 = (struct canon_rr*)k2;
log_assert(r1->rrset == r2->rrset);
return canonical_compare(r1->rrset, r1->rr_idx, r2->rr_idx);
}
/**
* Sort RRs for rrset in canonical order.
* Does not actually canonicalize the RR rdatas.
* Does not touch rrsigs.
* @param rrset: to sort.
* @param d: rrset data.
* @param sortree: tree to sort into.
* @param rrs: rr storage.
*/
static void
canonical_sort(struct ub_packed_rrset_key* rrset, struct packed_rrset_data* d,
rbtree_t* sortree, struct canon_rr* rrs)
{
size_t i;
/* insert into rbtree to sort and detect duplicates */
for(i=0; i<d->count; i++) {
rrs[i].node.key = &rrs[i];
rrs[i].rrset = rrset;
rrs[i].rr_idx = i;
if(!rbtree_insert(sortree, &rrs[i].node)) {
/* this was a duplicate */
}
}
}
/**
* Inser canonical owner name into buffer.
* @param buf: buffer to insert into at current position.
* @param k: rrset with its owner name.
* @param sig: signature with signer name and label count.
* must be length checked, at least 18 bytes long.
* @param can_owner: position in buffer returned for future use.
* @param can_owner_len: length of canonical owner name.
*/
static void
insert_can_owner(sldns_buffer* buf, struct ub_packed_rrset_key* k,
uint8_t* sig, uint8_t** can_owner, size_t* can_owner_len)
{
int rrsig_labels = (int)sig[3];
int fqdn_labels = dname_signame_label_count(k->rk.dname);
*can_owner = sldns_buffer_current(buf);
if(rrsig_labels == fqdn_labels) {
/* no change */
sldns_buffer_write(buf, k->rk.dname, k->rk.dname_len);
query_dname_tolower(*can_owner);
*can_owner_len = k->rk.dname_len;
return;
}
log_assert(rrsig_labels < fqdn_labels);
/* *. | fqdn(rightmost rrsig_labels) */
if(rrsig_labels < fqdn_labels) {
int i;
uint8_t* nm = k->rk.dname;
size_t len = k->rk.dname_len;
/* so skip fqdn_labels-rrsig_labels */
for(i=0; i<fqdn_labels-rrsig_labels; i++) {
dname_remove_label(&nm, &len);
}
*can_owner_len = len+2;
sldns_buffer_write(buf, (uint8_t*)"\001*", 2);
sldns_buffer_write(buf, nm, len);
query_dname_tolower(*can_owner);
}
}
/**
* Canonicalize Rdata in buffer.
* @param buf: buffer at position just after the rdata.
* @param rrset: rrset with type.
* @param len: length of the rdata (including rdatalen uint16).
*/
static void
canonicalize_rdata(sldns_buffer* buf, struct ub_packed_rrset_key* rrset,
size_t len)
{
uint8_t* datstart = sldns_buffer_current(buf)-len+2;
switch(ntohs(rrset->rk.type)) {
case LDNS_RR_TYPE_NXT:
case LDNS_RR_TYPE_NS:
case LDNS_RR_TYPE_MD:
case LDNS_RR_TYPE_MF:
case LDNS_RR_TYPE_CNAME:
case LDNS_RR_TYPE_MB:
case LDNS_RR_TYPE_MG:
case LDNS_RR_TYPE_MR:
case LDNS_RR_TYPE_PTR:
case LDNS_RR_TYPE_DNAME:
/* type only has a single argument, the name */
query_dname_tolower(datstart);
return;
case LDNS_RR_TYPE_MINFO:
case LDNS_RR_TYPE_RP:
case LDNS_RR_TYPE_SOA:
/* two names after another */
query_dname_tolower(datstart);
query_dname_tolower(datstart +
dname_valid(datstart, len-2));
return;
case LDNS_RR_TYPE_RT:
case LDNS_RR_TYPE_AFSDB:
case LDNS_RR_TYPE_KX:
case LDNS_RR_TYPE_MX:
/* skip fixed part */
if(len < 2+2+1) /* rdlen, skiplen, 1byteroot */
return;
datstart += 2;
query_dname_tolower(datstart);
return;
case LDNS_RR_TYPE_SIG:
/* downcase the RRSIG, compat with BIND (kept it from SIG) */
case LDNS_RR_TYPE_RRSIG:
/* skip fixed part */
if(len < 2+18+1)
return;
datstart += 18;
query_dname_tolower(datstart);
return;
case LDNS_RR_TYPE_PX:
/* skip, then two names after another */
if(len < 2+2+1)
return;
datstart += 2;
query_dname_tolower(datstart);
query_dname_tolower(datstart +
dname_valid(datstart, len-2-2));
return;
case LDNS_RR_TYPE_NAPTR:
if(len < 2+4)
return;
len -= 2+4;
datstart += 4;
if(len < (size_t)datstart[0]+1) /* skip text field */
return;
len -= (size_t)datstart[0]+1;
datstart += (size_t)datstart[0]+1;
if(len < (size_t)datstart[0]+1) /* skip text field */
return;
len -= (size_t)datstart[0]+1;
datstart += (size_t)datstart[0]+1;
if(len < (size_t)datstart[0]+1) /* skip text field */
return;
len -= (size_t)datstart[0]+1;
datstart += (size_t)datstart[0]+1;
if(len < 1) /* check name is at least 1 byte*/
return;
query_dname_tolower(datstart);
return;
case LDNS_RR_TYPE_SRV:
/* skip fixed part */
if(len < 2+6+1)
return;
datstart += 6;
query_dname_tolower(datstart);
return;
/* do not canonicalize NSEC rdata name, compat with
* from bind 9.4 signer, where it does not do so */
case LDNS_RR_TYPE_NSEC: /* type starts with the name */
case LDNS_RR_TYPE_HINFO: /* not downcased */
/* A6 not supported */
default:
/* nothing to do for unknown types */
return;
}
}
int rrset_canonical_equal(struct regional* region,
struct ub_packed_rrset_key* k1, struct ub_packed_rrset_key* k2)
{
struct rbtree_t sortree1, sortree2;
struct canon_rr *rrs1, *rrs2, *p1, *p2;
struct packed_rrset_data* d1=(struct packed_rrset_data*)k1->entry.data;
struct packed_rrset_data* d2=(struct packed_rrset_data*)k2->entry.data;
struct ub_packed_rrset_key fk;
struct packed_rrset_data fd;
size_t flen[2];
uint8_t* fdata[2];
/* basic compare */
if(k1->rk.dname_len != k2->rk.dname_len ||
k1->rk.flags != k2->rk.flags ||
k1->rk.type != k2->rk.type ||
k1->rk.rrset_class != k2->rk.rrset_class ||
query_dname_compare(k1->rk.dname, k2->rk.dname) != 0)
return 0;
if(d1->ttl != d2->ttl ||
d1->count != d2->count ||
d1->rrsig_count != d2->rrsig_count ||
d1->trust != d2->trust ||
d1->security != d2->security)
return 0;
/* init */
memset(&fk, 0, sizeof(fk));
memset(&fd, 0, sizeof(fd));
fk.entry.data = &fd;
fd.count = 2;
fd.rr_len = flen;
fd.rr_data = fdata;
rbtree_init(&sortree1, &canonical_tree_compare);
rbtree_init(&sortree2, &canonical_tree_compare);
if(d1->count > RR_COUNT_MAX || d2->count > RR_COUNT_MAX)
return 1; /* protection against integer overflow */
rrs1 = regional_alloc(region, sizeof(struct canon_rr)*d1->count);
rrs2 = regional_alloc(region, sizeof(struct canon_rr)*d2->count);
if(!rrs1 || !rrs2) return 1; /* alloc failure */
/* sort */
canonical_sort(k1, d1, &sortree1, rrs1);
canonical_sort(k2, d2, &sortree2, rrs2);
/* compare canonical-sorted RRs for canonical-equality */
if(sortree1.count != sortree2.count)
return 0;
p1 = (struct canon_rr*)rbtree_first(&sortree1);
p2 = (struct canon_rr*)rbtree_first(&sortree2);
while(p1 != (struct canon_rr*)RBTREE_NULL &&
p2 != (struct canon_rr*)RBTREE_NULL) {
flen[0] = d1->rr_len[p1->rr_idx];
flen[1] = d2->rr_len[p2->rr_idx];
fdata[0] = d1->rr_data[p1->rr_idx];
fdata[1] = d2->rr_data[p2->rr_idx];
if(canonical_compare(&fk, 0, 1) != 0)
return 0;
p1 = (struct canon_rr*)rbtree_next(&p1->node);
p2 = (struct canon_rr*)rbtree_next(&p2->node);
}
return 1;
}
/**
* Create canonical form of rrset in the scratch buffer.
* @param region: temporary region.
* @param buf: the buffer to use.
* @param k: the rrset to insert.
* @param sig: RRSIG rdata to include.
* @param siglen: RRSIG rdata len excluding signature field, but inclusive
* signer name length.
* @param sortree: if NULL is passed a new sorted rrset tree is built.
* Otherwise it is reused.
* @return false on alloc error.
*/
static int
rrset_canonical(struct regional* region, sldns_buffer* buf,
struct ub_packed_rrset_key* k, uint8_t* sig, size_t siglen,
struct rbtree_t** sortree)
{
struct packed_rrset_data* d = (struct packed_rrset_data*)k->entry.data;
uint8_t* can_owner = NULL;
size_t can_owner_len = 0;
struct canon_rr* walk;
struct canon_rr* rrs;
if(!*sortree) {
*sortree = (struct rbtree_t*)regional_alloc(region,
sizeof(rbtree_t));
if(!*sortree)
return 0;
if(d->count > RR_COUNT_MAX)
return 0; /* integer overflow protection */
rrs = regional_alloc(region, sizeof(struct canon_rr)*d->count);
if(!rrs) {
*sortree = NULL;
return 0;
}
rbtree_init(*sortree, &canonical_tree_compare);
canonical_sort(k, d, *sortree, rrs);
}
sldns_buffer_clear(buf);
sldns_buffer_write(buf, sig, siglen);
/* canonicalize signer name */
query_dname_tolower(sldns_buffer_begin(buf)+18);
RBTREE_FOR(walk, struct canon_rr*, (*sortree)) {
/* see if there is enough space left in the buffer */
if(sldns_buffer_remaining(buf) < can_owner_len + 2 + 2 + 4
+ d->rr_len[walk->rr_idx]) {
log_err("verify: failed to canonicalize, "
"rrset too big");
return 0;
}
/* determine canonical owner name */
if(can_owner)
sldns_buffer_write(buf, can_owner, can_owner_len);
else insert_can_owner(buf, k, sig, &can_owner,
&can_owner_len);
sldns_buffer_write(buf, &k->rk.type, 2);
sldns_buffer_write(buf, &k->rk.rrset_class, 2);
sldns_buffer_write(buf, sig+4, 4);
sldns_buffer_write(buf, d->rr_data[walk->rr_idx],
d->rr_len[walk->rr_idx]);
canonicalize_rdata(buf, k, d->rr_len[walk->rr_idx]);
}
sldns_buffer_flip(buf);
return 1;
}
/** pretty print rrsig error with dates */
static void
sigdate_error(const char* str, int32_t expi, int32_t incep, int32_t now)
{
struct tm tm;
char expi_buf[16];
char incep_buf[16];
char now_buf[16];
time_t te, ti, tn;
if(verbosity < VERB_QUERY)
return;
te = (time_t)expi;
ti = (time_t)incep;
tn = (time_t)now;
memset(&tm, 0, sizeof(tm));
if(gmtime_r(&te, &tm) && strftime(expi_buf, 15, "%Y%m%d%H%M%S", &tm)
&&gmtime_r(&ti, &tm) && strftime(incep_buf, 15, "%Y%m%d%H%M%S", &tm)
&&gmtime_r(&tn, &tm) && strftime(now_buf, 15, "%Y%m%d%H%M%S", &tm)) {
log_info("%s expi=%s incep=%s now=%s", str, expi_buf,
incep_buf, now_buf);
} else
log_info("%s expi=%u incep=%u now=%u", str, (unsigned)expi,
(unsigned)incep, (unsigned)now);
}
/** check rrsig dates */
static int
check_dates(struct val_env* ve, uint32_t unow,
uint8_t* expi_p, uint8_t* incep_p, char** reason)
{
/* read out the dates */
int32_t expi, incep, now;
memmove(&expi, expi_p, sizeof(expi));
memmove(&incep, incep_p, sizeof(incep));
expi = ntohl(expi);
incep = ntohl(incep);
/* get current date */
if(ve->date_override) {
if(ve->date_override == -1) {
verbose(VERB_ALGO, "date override: ignore date");
return 1;
}
now = ve->date_override;
verbose(VERB_ALGO, "date override option %d", (int)now);
} else now = (int32_t)unow;
/* check them */
if(incep - expi > 0) {
sigdate_error("verify: inception after expiration, "
"signature bad", expi, incep, now);
*reason = "signature inception after expiration";
return 0;
}
if(incep - now > 0) {
/* within skew ? (calc here to avoid calculation normally) */
int32_t skew = (expi-incep)/10;
if(skew < ve->skew_min) skew = ve->skew_min;
if(skew > ve->skew_max) skew = ve->skew_max;
if(incep - now > skew) {
sigdate_error("verify: signature bad, current time is"
" before inception date", expi, incep, now);
*reason = "signature before inception date";
return 0;
}
sigdate_error("verify warning suspicious signature inception "
" or bad local clock", expi, incep, now);
}
if(now - expi > 0) {
int32_t skew = (expi-incep)/10;
if(skew < ve->skew_min) skew = ve->skew_min;
if(skew > ve->skew_max) skew = ve->skew_max;
if(now - expi > skew) {
sigdate_error("verify: signature expired", expi,
incep, now);
*reason = "signature expired";
return 0;
}
sigdate_error("verify warning suspicious signature expiration "
" or bad local clock", expi, incep, now);
}
return 1;
}
/** adjust rrset TTL for verified rrset, compare to original TTL and expi */
static void
adjust_ttl(struct val_env* ve, uint32_t unow,
struct ub_packed_rrset_key* rrset, uint8_t* orig_p,
uint8_t* expi_p, uint8_t* incep_p)
{
struct packed_rrset_data* d =
(struct packed_rrset_data*)rrset->entry.data;
/* read out the dates */
int32_t origttl, expittl, expi, incep, now;
memmove(&origttl, orig_p, sizeof(origttl));
memmove(&expi, expi_p, sizeof(expi));
memmove(&incep, incep_p, sizeof(incep));
expi = ntohl(expi);
incep = ntohl(incep);
origttl = ntohl(origttl);
/* get current date */
if(ve->date_override) {
now = ve->date_override;
} else now = (int32_t)unow;
expittl = expi - now;
/* so now:
* d->ttl: rrset ttl read from message or cache. May be reduced
* origttl: original TTL from signature, authoritative TTL max.
* expittl: TTL until the signature expires.
*
* Use the smallest of these.
*/
if(d->ttl > (time_t)origttl) {
verbose(VERB_QUERY, "rrset TTL larger than original TTL,"
" adjusting TTL downwards");
d->ttl = origttl;
}
if(expittl > 0 && d->ttl > (time_t)expittl) {
verbose(VERB_ALGO, "rrset TTL larger than sig expiration ttl,"
" adjusting TTL downwards");
d->ttl = expittl;
}
}
enum sec_status
dnskey_verify_rrset_sig(struct regional* region, sldns_buffer* buf,
struct val_env* ve, time_t now,
struct ub_packed_rrset_key* rrset, struct ub_packed_rrset_key* dnskey,
size_t dnskey_idx, size_t sig_idx,
struct rbtree_t** sortree, int* buf_canon, char** reason)
{
enum sec_status sec;
uint8_t* sig; /* RRSIG rdata */
size_t siglen;
size_t rrnum = rrset_get_count(rrset);
uint8_t* signer; /* rrsig signer name */
size_t signer_len;
unsigned char* sigblock; /* signature rdata field */
unsigned int sigblock_len;
uint16_t ktag; /* DNSKEY key tag */
unsigned char* key; /* public key rdata field */
unsigned int keylen;
rrset_get_rdata(rrset, rrnum + sig_idx, &sig, &siglen);
/* min length of rdatalen, fixed rrsig, root signer, 1 byte sig */
if(siglen < 2+20) {
verbose(VERB_QUERY, "verify: signature too short");
*reason = "signature too short";
return sec_status_bogus;
}
if(!(dnskey_get_flags(dnskey, dnskey_idx) & DNSKEY_BIT_ZSK)) {
verbose(VERB_QUERY, "verify: dnskey without ZSK flag");
*reason = "dnskey without ZSK flag";
return sec_status_bogus;
}
if(dnskey_get_protocol(dnskey, dnskey_idx) != LDNS_DNSSEC_KEYPROTO) {
/* RFC 4034 says DNSKEY PROTOCOL MUST be 3 */
verbose(VERB_QUERY, "verify: dnskey has wrong key protocol");
*reason = "dnskey has wrong protocolnumber";
return sec_status_bogus;
}
/* verify as many fields in rrsig as possible */
signer = sig+2+18;
signer_len = dname_valid(signer, siglen-2-18);
if(!signer_len) {
verbose(VERB_QUERY, "verify: malformed signer name");
*reason = "signer name malformed";
return sec_status_bogus; /* signer name invalid */
}
if(!dname_subdomain_c(rrset->rk.dname, signer)) {
verbose(VERB_QUERY, "verify: signer name is off-tree");
*reason = "signer name off-tree";
return sec_status_bogus; /* signer name offtree */
}
sigblock = (unsigned char*)signer+signer_len;
if(siglen < 2+18+signer_len+1) {
verbose(VERB_QUERY, "verify: too short, no signature data");
*reason = "signature too short, no signature data";
return sec_status_bogus; /* sig rdf is < 1 byte */
}
sigblock_len = (unsigned int)(siglen - 2 - 18 - signer_len);
/* verify key dname == sig signer name */
if(query_dname_compare(signer, dnskey->rk.dname) != 0) {
verbose(VERB_QUERY, "verify: wrong key for rrsig");
log_nametypeclass(VERB_QUERY, "RRSIG signername is",
signer, 0, 0);
log_nametypeclass(VERB_QUERY, "the key name is",
dnskey->rk.dname, 0, 0);
*reason = "signer name mismatches key name";
return sec_status_bogus;
}
/* verify covered type */
/* memcmp works because type is in network format for rrset */
if(memcmp(sig+2, &rrset->rk.type, 2) != 0) {
verbose(VERB_QUERY, "verify: wrong type covered");
*reason = "signature covers wrong type";
return sec_status_bogus;
}
/* verify keytag and sig algo (possibly again) */
if((int)sig[2+2] != dnskey_get_algo(dnskey, dnskey_idx)) {
verbose(VERB_QUERY, "verify: wrong algorithm");
*reason = "signature has wrong algorithm";
return sec_status_bogus;
}
ktag = htons(dnskey_calc_keytag(dnskey, dnskey_idx));
if(memcmp(sig+2+16, &ktag, 2) != 0) {
verbose(VERB_QUERY, "verify: wrong keytag");
*reason = "signature has wrong keytag";
return sec_status_bogus;
}
/* verify labels is in a valid range */
if((int)sig[2+3] > dname_signame_label_count(rrset->rk.dname)) {
verbose(VERB_QUERY, "verify: labelcount out of range");
*reason = "signature labelcount out of range";
return sec_status_bogus;
}
/* original ttl, always ok */
if(!*buf_canon) {
/* create rrset canonical format in buffer, ready for
* signature */
if(!rrset_canonical(region, buf, rrset, sig+2,
18 + signer_len, sortree)) {
log_err("verify: failed due to alloc error");
return sec_status_unchecked;
}
*buf_canon = 1;
}
/* check that dnskey is available */
dnskey_get_pubkey(dnskey, dnskey_idx, &key, &keylen);
if(!key) {
verbose(VERB_QUERY, "verify: short DNSKEY RR");
return sec_status_unchecked;
}
/* verify */
sec = verify_canonrrset(buf, (int)sig[2+2],
sigblock, sigblock_len, key, keylen, reason);
if(sec == sec_status_secure) {
/* check if TTL is too high - reduce if so */
adjust_ttl(ve, now, rrset, sig+2+4, sig+2+8, sig+2+12);
/* verify inception, expiration dates
* Do this last so that if you ignore expired-sigs the
* rest is sure to be OK. */
if(!check_dates(ve, now, sig+2+8, sig+2+12, reason)) {
return sec_status_bogus;
}
}
return sec;
}
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