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/* $OpenBSD: validate.c,v 1.4 2019/06/19 16:30:37 deraadt Exp $ */
/*
* Copyright (c) 2019 Kristaps Dzonsons <kristaps@bsd.lv>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/socket.h>
#include <arpa/inet.h>
#include <assert.h>
#include <err.h>
#include <inttypes.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <openssl/ssl.h>
#include "extern.h"
static void
tracewarn(size_t idx, const struct auth *auths, size_t authsz)
{
for (;; idx = auths[idx].parent) {
warnx(" ...inheriting from: %s", auths[idx].fn);
if (auths[idx].parent == (size_t)idx)
break;
}
}
/*
* Walk up the chain of certificates trying to match our AS number to
* one of the allocations in that chain.
* Returns the index of the certificate in auths or -1 on error.
*/
static ssize_t
valid_as(uint32_t min, uint32_t max,
size_t idx, const struct auth *as, size_t asz)
{
int c;
assert(idx < asz);
/* Does this certificate cover our AS number? */
if (as[idx].cert->asz) {
c = as_check_covered(min, max,
as[idx].cert->as, as[idx].cert->asz);
if (c > 0)
return idx;
/*else if (c < 0)
return -1;*/
}
/* If it doesn't, walk up the chain. */
if (as[idx].parent == as[idx].id)
return -1;
return valid_as(min, max, as[idx].parent, as, asz);
}
/*
* Walk up the chain of certificates (really just the last one, but in
* the case of inheritence, the ones before) making sure that our IP
* prefix is covered in the first non-inheriting specification.
* Returns the index of the certificate in auths or -1 on error.
*/
static ssize_t
valid_ip(size_t idx, enum afi afi,
const unsigned char *min, const unsigned char *max,
const struct auth *as, size_t asz)
{
int c;
assert(idx < asz);
/* Does this certificate cover our IP prefix? */
c = ip_addr_check_covered(afi, min, max,
as[idx].cert->ips, as[idx].cert->ipsz);
if (c > 0)
return idx;
else if (c < 0)
return -1;
/* If it doesn't, walk up the chain. */
if (as[idx].parent == as[idx].id)
return -1;
return valid_ip(as[idx].parent, afi, min, max, as, asz);
}
/*
* Authenticate a trust anchor by making sure its resources are not
* inheriting and that the SKI is unique.
* Returns *authsz -1 on failure.
*/
ssize_t
valid_ta(const char *fn, const struct auth *auths,
size_t authsz, const struct cert *cert)
{
size_t i;
/* AS and IP resources must not inherit. */
if (cert->asz && cert->as[0].type == CERT_AS_INHERIT) {
warnx("%s: RFC 6487 (trust anchor): "
"inheriting AS resources", fn);
return -1;
}
for (i = 0; i < cert->ipsz; i++)
if (cert->ips[i].type == CERT_IP_INHERIT) {
warnx("%s: RFC 6487 (trust anchor): "
"inheriting IP resources", fn);
return -1;
}
/* SKI must not be a dupe. */
for (i = 0; i < authsz; i++)
if (strcmp(auths[i].cert->ski, cert->ski) == 0) {
warnx("%s: RFC 6487: duplicate SKI", fn);
return -1;
}
return authsz;
}
/*
* Make sure that the SKI doesn't already exist and return the parent by
* its AKI.
* Returns the parent index or -1 on failure.
*/
static ssize_t
valid_ski_aki(const char *fn, const struct auth *auths,
size_t authsz, const char *ski, const char *aki)
{
size_t i;
for (i = 0; i < authsz; i++)
if (strcmp(auths[i].cert->ski, ski) == 0) {
warnx("%s: RFC 6487: duplicate SKI", fn);
return -1;
}
for (i = 0; i < authsz; i++)
if (strcmp(auths[i].cert->ski, aki) == 0)
return i;
warnx("%s: RFC 6487: unknown AKI", fn);
return -1;
}
/*
* Validate a non-TA certificate: make sure its IP and AS resources are
* fully covered by those in the authority key (which must exist).
* Returns the parent certificate or -1 on failure.
*/
ssize_t
valid_cert(const char *fn, const struct auth *auths,
size_t authsz, const struct cert *cert)
{
ssize_t c, pp;
size_t i;
uint32_t min, max;
char buf1[64], buf2[64];
c = valid_ski_aki(fn, auths, authsz, cert->ski, cert->aki);
if (c < 0)
return -1;
for (i = 0; i < cert->asz; i++) {
if (cert->as[i].type == CERT_AS_INHERIT)
continue;
min = cert->as[i].type == CERT_AS_ID ?
cert->as[i].id : cert->as[i].range.min;
max = cert->as[i].type == CERT_AS_ID ?
cert->as[i].id : cert->as[i].range.max;
pp = valid_as(min, max, c, auths, authsz);
if (pp >= 0)
continue;
warnx("%s: RFC 6487: uncovered AS: "
"%u--%u", fn, min, max);
tracewarn(c, auths, authsz);
return -1;
}
for (i = 0; i < cert->ipsz; i++) {
pp = valid_ip(c, cert->ips[i].afi, cert->ips[i].min,
cert->ips[i].max, auths, authsz);
if (pp >= 0)
continue;
switch (cert->ips[i].type) {
case CERT_IP_RANGE:
ip_addr_print(&cert->ips[i].range.min,
cert->ips[i].afi, buf1, sizeof(buf1));
ip_addr_print(&cert->ips[i].range.max,
cert->ips[i].afi, buf2, sizeof(buf2));
warnx("%s: RFC 6487: uncovered IP: "
"%s--%s", fn, buf1, buf2);
break;
case CERT_IP_ADDR:
ip_addr_print(&cert->ips[i].ip,
cert->ips[i].afi, buf1, sizeof(buf1));
warnx("%s: RFC 6487: uncovered IP: "
"%s", fn, buf1);
case CERT_IP_INHERIT:
warnx("%s: RFC 6487: uncovered IP: "
"(inherit)", fn);
break;
}
tracewarn(c, auths, authsz);
return -1;
}
return c;
}
/*
* Validate our ROA: check that the SKI is unique, the AKI exists, and
* the IP prefix is also contained.
* Returns zero if not valid, non-zero if valid.
*/
int
valid_roa(const char *fn, const struct auth *auths,
size_t authsz, const struct roa *roa)
{
ssize_t c, pp;
size_t i;
char buf[64];
c = valid_ski_aki(fn, auths, authsz, roa->ski, roa->aki);
if (c < 0)
return 0;
for (i = 0; i < roa->ipsz; i++) {
pp = valid_ip(c, roa->ips[i].afi, roa->ips[i].min,
roa->ips[i].max, auths, authsz);
if (pp >= 0)
continue;
ip_addr_print(&roa->ips[i].addr,
roa->ips[i].afi, buf, sizeof(buf));
warnx("%s: RFC 6482: uncovered IP: "
"%s", fn, buf);
tracewarn(c, auths, authsz);
return 0;
}
return 1;
}
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