/*	$OpenBSD: cert.c,v 1.15 2020/04/02 09:16:43 claudio 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 <openssl/x509v3.h> /* DIST_POINT */

#include "extern.h"

/*
 * Type of ASIdentifier (RFC 3779, 3.2.3).
 */
#define	ASID_TYPE_ASNUM	0x00
#define ASID_TYPE_RDI	0x01
#define ASID_TYPE_MAX	ASID_TYPE_RDI

/*
 * A parsing sequence of a file (which may just be <stdin>).
 */
struct	parse {
	struct cert	*res; /* result */
	const char	*fn; /* currently-parsed file */
};

/*
 * Wrapper around ASN1_get_object() that preserves the current start
 * state and returns a more meaningful value.
 * Return zero on failure, non-zero on success.
 */
static int
ASN1_frame(struct parse *p, size_t sz,
	const unsigned char **cnt, long *cntsz, int *tag)
{
	int	 ret, pcls;

	assert(cnt != NULL && *cnt != NULL);
	assert(sz > 0);
	ret = ASN1_get_object(cnt, cntsz, tag, &pcls, sz);
	if ((ret & 0x80)) {
		cryptowarnx("%s: ASN1_get_object", p->fn);
		return 0;
	}
	return ASN1_object_size((ret & 0x01) ? 2 : 0, *cntsz, *tag);
}

/*
 * Append an IP address structure to our list of results.
 * This will also constrain us to having at most one inheritence
 * statement per AFI and also not have overlapping rages (as prohibited
 * in section 2.2.3.6).
 * It does not make sure that ranges can't coalesce, that is, that any
 * two ranges abut each other.
 * This is warned against in section 2.2.3.6, but doesn't change the
 * semantics of the system.
 * Return zero on failure (IP overlap) non-zero on success.
 */
static int
append_ip(struct parse *p, const struct cert_ip *ip)
{
	struct cert	*res = p->res;

	if (!ip_addr_check_overlap(ip, p->fn, p->res->ips, p->res->ipsz))
		return 0;
	res->ips = reallocarray(res->ips, res->ipsz + 1,
	    sizeof(struct cert_ip));
	if (res->ips == NULL)
		err(1, NULL);
	res->ips[res->ipsz++] = *ip;
	return 1;
}

/*
 * Append an AS identifier structure to our list of results.
 * Makes sure that the identifiers do not overlap or improperly inherit
 * as defined by RFC 3779 section 3.3.
 */
static int
append_as(struct parse *p, const struct cert_as *as)
{

	if (!as_check_overlap(as, p->fn, p->res->as, p->res->asz))
		return 0;
	p->res->as = reallocarray(p->res->as, p->res->asz + 1,
	    sizeof(struct cert_as));
	if (p->res->as == NULL)
		err(1, NULL);
	p->res->as[p->res->asz++] = *as;
	return 1;
}

/*
 * Construct a RFC 3779 2.2.3.8 range by its bit string.
 * Return zero on failure, non-zero on success.
 */
static int
sbgp_addr(struct parse *p,
	struct cert_ip *ip, const ASN1_BIT_STRING *bs)
{

	if (!ip_addr_parse(bs, ip->afi, p->fn, &ip->ip)) {
		warnx("%s: RFC 3779 section 2.2.3.8: IPAddress: "
		    "invalid IP address", p->fn);
		return 0;
	}
	if (!ip_cert_compose_ranges(ip)) {
		warnx("%s: RFC 3779 section 2.2.3.8: IPAddress: "
		    "IP address range reversed", p->fn);
		return 0;
	}
	return append_ip(p, ip);
}

/*
 * Parse the SIA manifest, 4.8.8.1.
 * There may be multiple different resources at this location, so throw
 * out all but the matching resource type.
 * Returns zero on failure, non-zero on success.
 */
static int
sbgp_sia_resource_mft(struct parse *p,
	const unsigned char *d, size_t dsz)
{
	ASN1_SEQUENCE_ANY	*seq;
	const ASN1_TYPE		*t;
	int			 rc = 0, ptag;
	char			buf[128];
	long			 plen;
	enum rtype		 rt;

	if ((seq = d2i_ASN1_SEQUENCE_ANY(NULL, &d, dsz)) == NULL) {
		cryptowarnx("%s: RFC 6487 section 4.8.8: SIA: "
		    "failed ASN.1 sequence parse", p->fn);
		goto out;
	}
	if (sk_ASN1_TYPE_num(seq) != 2) {
		warnx("%s: RFC 6487 section 4.8.8: SIA: "
		    "want 2 elements, have %d",
		    p->fn, sk_ASN1_TYPE_num(seq));
		goto out;
	}

	/* Composed of an OID and its continuation. */

	t = sk_ASN1_TYPE_value(seq, 0);
	if (t->type != V_ASN1_OBJECT) {
		warnx("%s: RFC 6487 section 4.8.8: SIA: "
		    "want ASN.1 object, have %s (NID %d)",
		    p->fn, ASN1_tag2str(t->type), t->type);
		goto out;
	}
	OBJ_obj2txt(buf, sizeof(buf), t->value.object, 1);

	/*
	 * Ignore all but manifest.
	 * Things we may want to consider later:
	 *  - 1.3.6.1.5.5.7.48.13 (rpkiNotify)
	 *  - 1.3.6.1.5.5.7.48.5 (CA repository)
	 */

	if (strcmp(buf, "1.3.6.1.5.5.7.48.10")) {
		rc = 1;
		goto out;
	}
	if (p->res->mft != NULL) {
		warnx("%s: RFC 6487 section 4.8.8: SIA: "
		    "MFT location already specified", p->fn);
		goto out;
	}

	t = sk_ASN1_TYPE_value(seq, 1);
	if (t->type != V_ASN1_OTHER) {
		warnx("%s: RFC 6487 section 4.8.8: SIA: "
		    "want ASN.1 external, have %s (NID %d)",
		    p->fn, ASN1_tag2str(t->type), t->type);
		goto out;
	}

	/* FIXME: there must be a way to do this without ASN1_frame. */

	d = t->value.asn1_string->data;
	dsz = t->value.asn1_string->length;
	if (!ASN1_frame(p, dsz, &d, &plen, &ptag))
		goto out;

	if ((p->res->mft = strndup((const char *)d, plen)) == NULL)
		err(1, NULL);

	/* Make sure it's an MFT rsync address. */

	if (!rsync_uri_parse(NULL, NULL, NULL,
	    NULL, NULL, NULL, &rt, p->res->mft)) {
		warnx("%s: RFC 6487 section 4.8.8: SIA: "
		    "failed to parse rsync URI", p->fn);
		free(p->res->mft);
		p->res->mft = NULL;
		goto out;
	}
	if (rt != RTYPE_MFT) {
		warnx("%s: RFC 6487 section 4.8.8: SIA: "
		    "invalid rsync URI suffix", p->fn);
		free(p->res->mft);
		p->res->mft = NULL;
		goto out;
	}

	rc = 1;
out:
	sk_ASN1_TYPE_pop_free(seq, ASN1_TYPE_free);
	return rc;
}

/*
 * Multiple locations as defined in RFC 6487, 4.8.8.1.
 * Returns zero on failure, non-zero on success.
 */
static int
sbgp_sia_resource(struct parse *p, const unsigned char *d, size_t dsz)
{
	ASN1_SEQUENCE_ANY	*seq;
	const ASN1_TYPE		*t;
	int			 rc = 0, i;

	if ((seq = d2i_ASN1_SEQUENCE_ANY(NULL, &d, dsz)) == NULL) {
		cryptowarnx("%s: RFC 6487 section 4.8.8: SIA: "
		    "failed ASN.1 sequence parse", p->fn);
		goto out;
	}

	for (i = 0; i < sk_ASN1_TYPE_num(seq); i++) {
		t = sk_ASN1_TYPE_value(seq, i);
		if (t->type != V_ASN1_SEQUENCE) {
			warnx("%s: RFC 6487 section 4.8.8: SIA: "
			    "want ASN.1 sequence, have %s (NID %d)",
			    p->fn, ASN1_tag2str(t->type), t->type);
			goto out;
		}
		d = t->value.asn1_string->data;
		dsz = t->value.asn1_string->length;
		if (!sbgp_sia_resource_mft(p, d, dsz))
			goto out;
	}

	rc = 1;
out:
	sk_ASN1_TYPE_pop_free(seq, ASN1_TYPE_free);
	return rc;
}

/*
 * Parse "Subject Information Access" extension, RFC 6487 4.8.8.
 * Returns zero on failure, non-zero on success.
 */
static int
sbgp_sia(struct parse *p, X509_EXTENSION *ext)
{
	unsigned char		*sv = NULL;
	const unsigned char	*d;
	ASN1_SEQUENCE_ANY	*seq = NULL;
	const ASN1_TYPE		*t;
	int			 dsz, rc = 0;

	if ((dsz = i2d_X509_EXTENSION(ext, &sv)) < 0) {
		cryptowarnx("%s: RFC 6487 section 4.8.8: SIA: "
		    "failed extension parse", p->fn);
		goto out;
	}
	d = sv;

	if ((seq = d2i_ASN1_SEQUENCE_ANY(NULL, &d, dsz)) == NULL) {
		cryptowarnx("%s: RFC 6487 section 4.8.8: SIA: "
		    "failed ASN.1 sequence parse", p->fn);
		goto out;
	}
	if (sk_ASN1_TYPE_num(seq) != 2) {
		warnx("%s: RFC 6487 section 4.8.8: SIA: "
		    "want 2 elements, have %d", p->fn,
		    sk_ASN1_TYPE_num(seq));
		goto out;
	}

	t = sk_ASN1_TYPE_value(seq, 0);
	if (t->type != V_ASN1_OBJECT) {
		warnx("%s: RFC 6487 section 4.8.8: SIA: "
		    "want ASN.1 object, have %s (NID %d)",
		    p->fn, ASN1_tag2str(t->type), t->type);
		goto out;
	}
	if (OBJ_obj2nid(t->value.object) != NID_sinfo_access) {
		warnx("%s: RFC 6487 section 4.8.8: SIA: "
		    "incorrect OID, have %s (NID %d)", p->fn,
		    ASN1_tag2str(OBJ_obj2nid(t->value.object)),
		    OBJ_obj2nid(t->value.object));
		goto out;
	}

	t = sk_ASN1_TYPE_value(seq, 1);
	if (t->type != V_ASN1_OCTET_STRING) {
		warnx("%s: RFC 6487 section 4.8.8: SIA: "
		    "want ASN.1 octet string, have %s (NID %d)",
		    p->fn, ASN1_tag2str(t->type), t->type);
		goto out;
	}

	d = t->value.octet_string->data;
	dsz = t->value.octet_string->length;
	if (!sbgp_sia_resource(p, d, dsz))
		goto out;

	rc = 1;
out:
	sk_ASN1_TYPE_pop_free(seq, ASN1_TYPE_free);
	free(sv);
	return rc;
}

/*
 * Parse a range of addresses as in 3.2.3.8.
 * Returns zero on failure, non-zero on success.
 */
static int
sbgp_asrange(struct parse *p, const unsigned char *d, size_t dsz)
{
	struct cert_as		 as;
	ASN1_SEQUENCE_ANY	*seq;
	const ASN1_TYPE		*t;
	int			 rc = 0;

	if ((seq = d2i_ASN1_SEQUENCE_ANY(NULL, &d, dsz)) == NULL) {
		cryptowarnx("%s: RFC 3779 section 3.2.3.8: ASRange: "
		    "failed ASN.1 sequence parse", p->fn);
		goto out;
	}
	if (sk_ASN1_TYPE_num(seq) != 2) {
		warnx("%s: RFC 3779 section 3.2.3.8: ASRange: "
		    "want 2 elements, have %d", p->fn,
		    sk_ASN1_TYPE_num(seq));
		goto out;
	}

	memset(&as, 0, sizeof(struct cert_as));
	as.type = CERT_AS_RANGE;

	t = sk_ASN1_TYPE_value(seq, 0);
	if (t->type != V_ASN1_INTEGER) {
		warnx("%s: RFC 3779 section 3.2.3.8: ASRange: "
		    "want ASN.1 integer, have %s (NID %d)",
		    p->fn, ASN1_tag2str(t->type), t->type);
		goto out;
	}
	if (!as_id_parse(t->value.integer, &as.range.min)) {
		warnx("%s: RFC 3770 section 3.2.3.8 (via RFC 1930): "
		    "malformed AS identifier", p->fn);
		return 0;
	}

	t = sk_ASN1_TYPE_value(seq, 1);
	if (t->type != V_ASN1_INTEGER) {
		warnx("%s: RFC 3779 section 3.2.3.8: ASRange: "
		    "want ASN.1 integer, have %s (NID %d)",
		    p->fn, ASN1_tag2str(t->type), t->type);
		goto out;
	}
	if (!as_id_parse(t->value.integer, &as.range.max)) {
		warnx("%s: RFC 3770 section 3.2.3.8 (via RFC 1930): "
		    "malformed AS identifier", p->fn);
		return 0;
	}

	if (as.range.max == as.range.min) {
		warnx("%s: RFC 3379 section 3.2.3.8: ASRange: "
		    "range is singular", p->fn);
		goto out;
	} else if (as.range.max < as.range.min) {
		warnx("%s: RFC 3379 section 3.2.3.8: ASRange: "
		    "range is out of order", p->fn);
		goto out;
	}

	if (!append_as(p, &as))
		goto out;
	rc = 1;
out:
	sk_ASN1_TYPE_pop_free(seq, ASN1_TYPE_free);
	return rc;
}

/*
 * Parse an entire 3.2.3.10 integer type.
 */
static int
sbgp_asid(struct parse *p, const ASN1_INTEGER *i)
{
	struct cert_as	 as;

	memset(&as, 0, sizeof(struct cert_as));
	as.type = CERT_AS_ID;

	if (!as_id_parse(i, &as.id)) {
		warnx("%s: RFC 3770 section 3.2.3.10 (via RFC 1930): "
		    "malformed AS identifier", p->fn);
		return 0;
	}
	if (as.id == 0) {
		warnx("%s: RFC 3770 section 3.2.3.10 (via RFC 1930): "
		    "AS identifier zero is reserved", p->fn);
		return 0;
	}

	return append_as(p, &as);
}

/*
 * Parse one of RFC 3779 3.2.3.2.
 * Returns zero on failure, non-zero on success.
 */
static int
sbgp_asnum(struct parse *p, const unsigned char *d, size_t dsz)
{
	struct cert_as		 as;
	ASN1_TYPE		*t, *tt;
	ASN1_SEQUENCE_ANY	*seq = NULL;
	int			 i, rc = 0;
	const unsigned char	*sv = d;

	/* We can either be a null (inherit) or sequence. */

	if ((t = d2i_ASN1_TYPE(NULL, &d, dsz)) == NULL) {
		cryptowarnx("%s: RFC 3779 section 3.2.3.2: ASIdentifierChoice: "
		    "failed ASN.1 type parse", p->fn);
		goto out;
	}

	/*
	 * Section 3779 3.2.3.3 is to inherit with an ASN.1 NULL type,
	 * which is the easy case.
	 */

	switch (t->type) {
	case V_ASN1_NULL:
		memset(&as, 0, sizeof(struct cert_as));
		as.type = CERT_AS_INHERIT;
		if (!append_as(p, &as))
			goto out;
		rc = 1;
		goto out;
	case V_ASN1_SEQUENCE:
		break;
	default:
		warnx("%s: RFC 3779 section 3.2.3.2: ASIdentifierChoice: "
		    "want ASN.1 sequence or null, have %s (NID %d)",
		    p->fn, ASN1_tag2str(t->type), t->type);
		goto out;
	}

	/* This is RFC 3779 3.2.3.4. */

	if ((seq = d2i_ASN1_SEQUENCE_ANY(NULL, &sv, dsz)) == NULL) {
		cryptowarnx("%s: RFC 3779 section 3.2.3.2: ASIdentifierChoice: "
		    "failed ASN.1 sequence parse", p->fn);
		goto out;
	}

	/* Accepts RFC 3779 3.2.3.6 or 3.2.3.7 (sequence). */

	for (i = 0; i < sk_ASN1_TYPE_num(seq); i++) {
		tt = sk_ASN1_TYPE_value(seq, i);
		switch (tt->type) {
		case V_ASN1_INTEGER:
			if (!sbgp_asid(p, tt->value.integer))
				goto out;
			break;
		case V_ASN1_SEQUENCE:
			d = tt->value.asn1_string->data;
			dsz = tt->value.asn1_string->length;
			if (!sbgp_asrange(p, d, dsz))
				goto out;
			break;
		default:
			warnx("%s: RFC 3779 section 3.2.3.4: IPAddressOrRange: "
			    "want ASN.1 sequence or integer, have %s (NID %d)",
			    p->fn, ASN1_tag2str(tt->type), tt->type);
			goto out;
		}
	}

	rc = 1;
out:
	ASN1_TYPE_free(t);
	sk_ASN1_TYPE_pop_free(seq, ASN1_TYPE_free);
	return rc;
}

/*
 * Parse RFC 6487 4.8.11 X509v3 extension, with syntax documented in RFC
 * 3779 starting in section 3.2.
 * Returns zero on failure, non-zero on success.
 */
static int
sbgp_assysnum(struct parse *p, X509_EXTENSION *ext)
{
	unsigned char		*sv = NULL;
	const unsigned char	*d;
	ASN1_SEQUENCE_ANY	*seq = NULL, *sseq = NULL;
	const ASN1_TYPE		*t;
	int			 dsz, rc = 0, i, ptag;
	long			 plen;

	if ((dsz = i2d_X509_EXTENSION(ext, &sv)) < 0) {
		cryptowarnx("%s: RFC 6487 section 4.8.11: autonomousSysNum: "
		    "failed extension parse", p->fn);
		goto out;
	}

	/* Start with RFC 3779, section 3.2 top-level. */

	d = sv;
	if ((seq = d2i_ASN1_SEQUENCE_ANY(NULL, &d, dsz)) == NULL) {
		cryptowarnx("%s: RFC 6487 section 4.8.11: autonomousSysNum: "
		    "failed ASN.1 sequence parse", p->fn);
		goto out;
	}
	if (sk_ASN1_TYPE_num(seq) != 3) {
		warnx("%s: RFC 6487 section 4.8.11: autonomousSysNum: "
		    "want 3 elements, have %d", p->fn,
		    sk_ASN1_TYPE_num(seq));
		goto out;
	}

	t = sk_ASN1_TYPE_value(seq, 0);
	if (t->type != V_ASN1_OBJECT) {
		warnx("%s: RFC 6487 section 4.8.11: autonomousSysNum: "
		    "want ASN.1 object, have %s (NID %d)",
		    p->fn, ASN1_tag2str(t->type), t->type);
		goto out;
	}

	/* FIXME: verify OID. */

	t = sk_ASN1_TYPE_value(seq, 1);
	if (t->type != V_ASN1_BOOLEAN) {
		warnx("%s: RFC 6487 section 4.8.11: autonomousSysNum: "
		    "want ASN.1 boolean, have %s (NID %d)",
		    p->fn, ASN1_tag2str(t->type), t->type);
		goto out;
	}

	t = sk_ASN1_TYPE_value(seq, 2);
	if (t->type != V_ASN1_OCTET_STRING) {
		warnx("%s: RFC 6487 section 4.8.11: autonomousSysNum: "
		    "want ASN.1 octet string, have %s (NID %d)",
		    p->fn, ASN1_tag2str(t->type), t->type);
		goto out;
	}

	/* Within RFC 3779 3.2.3, check 3.2.3.1. */

	d = t->value.octet_string->data;
	dsz = t->value.octet_string->length;

	if ((sseq = d2i_ASN1_SEQUENCE_ANY(NULL, &d, dsz)) == NULL) {
		cryptowarnx("%s: RFC 3779 section 3.2.3.1: ASIdentifiers: "
		    "failed ASN.1 sequence parse", p->fn);
		goto out;
	}

	/* Scan through for private 3.2.3.2 classes. */

	for (i = 0; i < sk_ASN1_TYPE_num(sseq); i++) {
		t = sk_ASN1_TYPE_value(sseq, i);
		if (t->type != V_ASN1_OTHER) {
			warnx("%s: RFC 3779 section 3.2.3.1: ASIdentifiers: "
			    "want ASN.1 explicit, have %s (NID %d)", p->fn,
			    ASN1_tag2str(t->type), t->type);
			goto out;
		}

		/* Use the low-level ASN1_frame. */

		d = t->value.asn1_string->data;
		dsz = t->value.asn1_string->length;
		if (!ASN1_frame(p, dsz, &d, &plen, &ptag))
			goto out;

		/* Ignore bad AS identifiers and RDI entries. */

		if (ptag > ASID_TYPE_MAX) {
			warnx("%s: RFC 3779 section 3.2.3.1: ASIdentifiers: "
			    "unknown explicit tag 0x%02x", p->fn, ptag);
			goto out;
		} else if (ptag == ASID_TYPE_RDI)
			continue;

		if (!sbgp_asnum(p, d, plen))
			goto out;
	}

	rc = 1;
out:
	sk_ASN1_TYPE_pop_free(seq, ASN1_TYPE_free);
	sk_ASN1_TYPE_pop_free(sseq, ASN1_TYPE_free);
	free(sv);
	return rc;
}

/*
 * Parse RFC 3779 2.2.3.9 range of addresses.
 * Return zero on failure, non-zero on success.
 */
static int
sbgp_addr_range(struct parse *p, struct cert_ip *ip,
	const unsigned char *d, size_t dsz)
{
	ASN1_SEQUENCE_ANY	*seq;
	const ASN1_TYPE		*t;
	int			 rc = 0;

	if ((seq = d2i_ASN1_SEQUENCE_ANY(NULL, &d, dsz)) == NULL) {
		cryptowarnx("%s: RFC 3779 section 2.2.3.9: IPAddressRange: "
		    "failed ASN.1 sequence parse", p->fn);
		goto out;
	}
	if (sk_ASN1_TYPE_num(seq) != 2) {
		warnx("%s: RFC 3779 section 2.2.3.9: IPAddressRange: "
		    "want 2 elements, have %d", p->fn, sk_ASN1_TYPE_num(seq));
		goto out;
	}

	t = sk_ASN1_TYPE_value(seq, 0);
	if (t->type != V_ASN1_BIT_STRING) {
		warnx("%s: RFC 3779 section 2.2.3.9: IPAddressRange: "
		    "want ASN.1 bit string, have %s (NID %d)",
		    p->fn, ASN1_tag2str(t->type), t->type);
		goto out;
	}
	if (!ip_addr_parse(t->value.bit_string,
	    ip->afi, p->fn, &ip->range.min)) {
		warnx("%s: RFC 3779 section 2.2.3.9: IPAddressRange: "
		    "invalid IP address", p->fn);
		goto out;
	}

	t = sk_ASN1_TYPE_value(seq, 1);
	if (t->type != V_ASN1_BIT_STRING) {
		warnx("%s: RFC 3779 section 2.2.3.9: IPAddressRange: "
		    "want ASN.1 bit string, have %s (NID %d)",
		    p->fn, ASN1_tag2str(t->type), t->type);
		goto out;
	}
	if (!ip_addr_parse(t->value.bit_string,
	    ip->afi, p->fn, &ip->range.max)) {
		warnx("%s: RFC 3779 section 2.2.3.9: IPAddressRange: "
		    "invalid IP address", p->fn);
		goto out;
	}

	if (!ip_cert_compose_ranges(ip)) {
		warnx("%s: RFC 3779 section 2.2.3.9: IPAddressRange: "
		    "IP address range reversed", p->fn);
		return 0;
	}

	rc = append_ip(p, ip);
out:
	sk_ASN1_TYPE_pop_free(seq, ASN1_TYPE_free);
	return rc;
}

/*
 * Parse an IP address or range, RFC 3779 2.2.3.7.
 * We don't constrain this parse (as specified in section 2.2.3.6) to
 * having any kind of order.
 * Returns zero on failure, non-zero on success.
 */
static int
sbgp_addr_or_range(struct parse *p, struct cert_ip *ip,
	const unsigned char *d, size_t dsz)
{
	struct cert_ip		 nip;
	ASN1_SEQUENCE_ANY	*seq;
	const ASN1_TYPE		*t;
	int			 i, rc = 0;

	if ((seq = d2i_ASN1_SEQUENCE_ANY(NULL, &d, dsz)) == NULL) {
		cryptowarnx("%s: RFC 3779 section 2.2.3.7: IPAddressOrRange: "
		    "failed ASN.1 sequence parse", p->fn);
		goto out;
	}

	/* Either RFC 3779 2.2.3.8 or 2.2.3.9. */

	for (i = 0; i < sk_ASN1_TYPE_num(seq); i++) {
		nip = *ip;
		t = sk_ASN1_TYPE_value(seq, i);
		switch (t->type) {
		case V_ASN1_BIT_STRING:
			nip.type = CERT_IP_ADDR;
			if (!sbgp_addr(p, &nip, t->value.bit_string))
				goto out;
			break;
		case V_ASN1_SEQUENCE:
			nip.type = CERT_IP_RANGE;
			d = t->value.asn1_string->data;
			dsz = t->value.asn1_string->length;
			if (!sbgp_addr_range(p, &nip, d, dsz))
				goto out;
			break;
		default:
			warnx("%s: RFC 3779 section 2.2.3.7: IPAddressOrRange: "
			    "want ASN.1 sequence or bit string, have %s (NID %d)",
			    p->fn, ASN1_tag2str(t->type), t->type);
			goto out;
		}
	}

	rc = 1;
out:
	sk_ASN1_TYPE_pop_free(seq, ASN1_TYPE_free);
	return rc;
}

/*
 * Parse a sequence of address families as in RFC 3779 sec. 2.2.3.2.
 * Ignore several stipulations of the RFC (2.2.3.3).
 * Namely, we don't require entries to be ordered in any way (type, AFI
 * or SAFI group, etc.).
 * This is because it doesn't matter for our purposes: we're going to
 * validate in the same way regardless.
 * Returns zero no failure, non-zero on success.
 */
static int
sbgp_ipaddrfam(struct parse *p, const unsigned char *d, size_t dsz)
{
	struct cert_ip		 ip;
	ASN1_SEQUENCE_ANY	*seq;
	const ASN1_TYPE		*t;
	int			 rc = 0;

	memset(&ip, 0, sizeof(struct cert_ip));

	if ((seq = d2i_ASN1_SEQUENCE_ANY(NULL, &d, dsz)) == NULL) {
		cryptowarnx("%s: RFC 3779 section 2.2.3.2: IPAddressFamily: "
		    "failed ASN.1 sequence parse", p->fn);
		goto out;
	}
	if (sk_ASN1_TYPE_num(seq) != 2) {
		warnx("%s: RFC 3779 section 2.2.3.2: IPAddressFamily: "
		    "want 2 elements, have %d",
		    p->fn, sk_ASN1_TYPE_num(seq));
		goto out;
	}

	/* Get address family, RFC 3779, 2.2.3.3. */

	t = sk_ASN1_TYPE_value(seq, 0);
	if (t->type != V_ASN1_OCTET_STRING) {
		warnx("%s: RFC 3779 section 2.2.3.2: addressFamily: "
		    "want ASN.1 octet string, have %s (NID %d)",
		    p->fn, ASN1_tag2str(t->type), t->type);
		goto out;
	}

	if (!ip_addr_afi_parse(p->fn, t->value.octet_string, &ip.afi)) {
		warnx("%s: RFC 3779 section 2.2.3.2: addressFamily: "
		    "invalid AFI", p->fn);
		goto out;
	}

	/* Either sequence or null (inherit), RFC 3779 sec. 2.2.3.4. */

	t = sk_ASN1_TYPE_value(seq, 1);
	switch (t->type) {
	case V_ASN1_SEQUENCE:
		d = t->value.asn1_string->data;
		dsz = t->value.asn1_string->length;
		if (!sbgp_addr_or_range(p, &ip, d, dsz))
			goto out;
		break;
	case V_ASN1_NULL:
		ip.type = CERT_IP_INHERIT;
		if (!append_ip(p, &ip))
			goto out;
		break;
	default:
		warnx("%s: RFC 3779 section 2.2.3.2: IPAddressChoice: "
		    "want ASN.1 sequence or null, have %s (NID %d)",
		    p->fn, ASN1_tag2str(t->type), t->type);
		goto out;
	}

	rc = 1;
out:
	sk_ASN1_TYPE_pop_free(seq, ASN1_TYPE_free);
	return rc;
}

/*
 * Parse an sbgp-ipAddrBlock X509 extension, RFC 6487 4.8.10, with
 * syntax documented in RFC 3779 starting in section 2.2.
 * Returns zero on failure, non-zero on success.
 */
static int
sbgp_ipaddrblk(struct parse *p, X509_EXTENSION *ext)
{
	int			 dsz, rc = 0;
	unsigned char		*sv = NULL;
	const unsigned char	*d;
	ASN1_SEQUENCE_ANY	*seq = NULL, *sseq = NULL;
	const ASN1_TYPE		*t = NULL;
	int			 i;

	if ((dsz = i2d_X509_EXTENSION(ext, &sv)) < 0) {
		cryptowarnx("%s: RFC 6487 section 4.8.10: sbgp-ipAddrBlock: "
		    "failed extension parse", p->fn);
		goto out;
	}
	d = sv;

	if ((seq = d2i_ASN1_SEQUENCE_ANY(NULL, &d, dsz)) == NULL) {
		cryptowarnx("%s: RFC 6487 section 4.8.10: sbgp-ipAddrBlock: "
		    "failed ASN.1 sequence parse", p->fn);
		goto out;
	}
	if (sk_ASN1_TYPE_num(seq) != 3) {
		warnx("%s: RFC 6487 section 4.8.10: sbgp-ipAddrBlock: "
		    "want 3 elements, have %d",
		    p->fn, sk_ASN1_TYPE_num(seq));
		goto out;
	}

	t = sk_ASN1_TYPE_value(seq, 0);
	if (t->type != V_ASN1_OBJECT) {
		warnx("%s: RFC 6487 section 4.8.10: sbgp-ipAddrBlock: "
		    "want ASN.1 object, have %s (NID %d)",
		    p->fn, ASN1_tag2str(t->type), t->type);
		goto out;
	}

	/* FIXME: verify OID. */

	t = sk_ASN1_TYPE_value(seq, 1);
	if (t->type != V_ASN1_BOOLEAN) {
		warnx("%s: RFC 6487 section 4.8.10: sbgp-ipAddrBlock: "
		    "want ASN.1 boolean, have %s (NID %d)",
		    p->fn, ASN1_tag2str(t->type), t->type);
		goto out;
	}

	t = sk_ASN1_TYPE_value(seq, 2);
	if (t->type != V_ASN1_OCTET_STRING) {
		warnx("%s: RFC 6487 section 4.8.10: sbgp-ipAddrBlock: "
		    "want ASN.1 octet string, have %s (NID %d)",
		    p->fn, ASN1_tag2str(t->type), t->type);
		goto out;
	}

	/* The blocks sequence, RFC 3779 2.2.3.1. */

	d = t->value.octet_string->data;
	dsz = t->value.octet_string->length;

	if ((sseq = d2i_ASN1_SEQUENCE_ANY(NULL, &d, dsz)) == NULL) {
		cryptowarnx("%s: RFC 3779 section 2.2.3.1: IPAddrBlocks: "
		    "failed ASN.1 sequence parse", p->fn);
		goto out;
	}

	/* Each sequence element contains RFC 3779 sec. 2.2.3.2. */

	for (i = 0; i < sk_ASN1_TYPE_num(sseq); i++) {
		t = sk_ASN1_TYPE_value(sseq, i);
		if (t->type != V_ASN1_SEQUENCE) {
			warnx("%s: RFC 3779 section 2.2.3.2: IPAddressFamily: "
			    "want ASN.1 sequence, have %s (NID %d)",
			    p->fn, ASN1_tag2str(t->type), t->type);
			goto out;
		}
		d = t->value.asn1_string->data;
		dsz = t->value.asn1_string->length;
		if (!sbgp_ipaddrfam(p, d, dsz))
			goto out;
	}

	rc = 1;
out:
	sk_ASN1_TYPE_pop_free(seq, ASN1_TYPE_free);
	sk_ASN1_TYPE_pop_free(sseq, ASN1_TYPE_free);
	free(sv);
	return rc;
}

/*
 * Parse and partially validate an RPKI X509 certificate (either a trust
 * anchor or a certificate) as defined in RFC 6487.
 * If "ta" is set, this is a trust anchor and must be self-signed.
 * Returns the parse results or NULL on failure ("xp" will be NULL too).
 * On success, free the pointer with cert_free() and make sure that "xp"
 * is also dereferenced.
 */
static struct cert *
cert_parse_inner(X509 **xp, const char *fn, const unsigned char *dgst, int ta)
{
	int		 rc = 0, extsz, c, sz;
	size_t		 i;
	X509		*x = NULL;
	X509_EXTENSION	*ext = NULL;
	ASN1_OBJECT	*obj;
	struct parse	 p;
	BIO		*bio = NULL, *shamd;
	FILE		*f;
	EVP_MD		*md;
	char		 mdbuf[EVP_MAX_MD_SIZE];

	*xp = NULL;

	if ((f = fopen(fn, "rb")) == NULL) {
		warn("%s", fn);
		return NULL;
	}

	if ((bio = BIO_new_fp(f, BIO_CLOSE)) == NULL) {
		if (verbose > 0)
			cryptowarnx("%s: BIO_new_file", fn);
		return NULL;
	}

	memset(&p, 0, sizeof(struct parse));
	p.fn = fn;
	if ((p.res = calloc(1, sizeof(struct cert))) == NULL)
		err(1, NULL);

	/*
	 * If we have a digest specified, create an MD chain that will
	 * automatically compute a digest during the X509 creation.
	 */

	if (dgst != NULL) {
		if ((shamd = BIO_new(BIO_f_md())) == NULL)
			cryptoerrx("BIO_new");
		if (!BIO_set_md(shamd, EVP_sha256()))
			cryptoerrx("BIO_set_md");
		if ((bio = BIO_push(shamd, bio)) == NULL)
			cryptoerrx("BIO_push");
	}

	if ((x = *xp = d2i_X509_bio(bio, NULL)) == NULL) {
		cryptowarnx("%s: d2i_X509_bio", p.fn);
		goto out;
	}

	/*
	 * If we have a digest, find it in the chain (we'll already have
	 * made it, so assert otherwise) and verify it.
	 */

	if (dgst != NULL) {
		shamd = BIO_find_type(bio, BIO_TYPE_MD);
		assert(shamd != NULL);

		if (!BIO_get_md(shamd, &md))
			cryptoerrx("BIO_get_md");
		assert(EVP_MD_type(md) == NID_sha256);

		if ((sz = BIO_gets(shamd, mdbuf, EVP_MAX_MD_SIZE)) < 0)
			cryptoerrx("BIO_gets");
		assert(sz == SHA256_DIGEST_LENGTH);

		if (memcmp(mdbuf, dgst, SHA256_DIGEST_LENGTH)) {
			if (verbose > 0)
				warnx("%s: bad message digest", p.fn);
			goto out;
		}
	}

	/* Look for X509v3 extensions. */

	if ((extsz = X509_get_ext_count(x)) < 0)
		cryptoerrx("X509_get_ext_count");

	for (i = 0; i < (size_t)extsz; i++) {
		ext = X509_get_ext(x, i);
		assert(ext != NULL);
		obj = X509_EXTENSION_get_object(ext);
		assert(obj != NULL);
		c = 1;

		switch (OBJ_obj2nid(obj)) {
		case NID_sbgp_ipAddrBlock:
			c = sbgp_ipaddrblk(&p, ext);
			break;
		case NID_sbgp_autonomousSysNum:
			c = sbgp_assysnum(&p, ext);
			break;
		case NID_sinfo_access:
			c = sbgp_sia(&p, ext);
			break;
		case NID_crl_distribution_points:
			/* ignored here, handled later */
			break;
		case NID_authority_key_identifier:
			free(p.res->aki);
			p.res->aki = x509_get_aki_ext(ext, p.fn);
			c = (p.res->aki != NULL);
			break;
		case NID_subject_key_identifier:
			free(p.res->ski);
			p.res->ski = x509_get_ski_ext(ext, p.fn);
			c = (p.res->ski != NULL);
			break;
		default:
			/* {
				char objn[64];
				OBJ_obj2txt(objn, sizeof(objn), obj, 0);
				warnx("%s: ignoring %s (NID %d)",
					p.fn, objn, OBJ_obj2nid(obj));
			} */
			break;
		}
		if (c == 0)
			goto out;
	}

	if (!ta)
		p.res->crl = x509_get_crl(x, p.fn);

	/* Validation on required fields. */

	if (p.res->ski == NULL) {
		warnx("%s: RFC 6487 section 8.4.2: "
		    "missing SKI", p.fn);
		goto out;
	}

	if (ta && p.res->aki != NULL && strcmp(p.res->aki, p.res->ski)) {
		warnx("%s: RFC 6487 section 8.4.2: "
		    "trust anchor AKI, if specified, must match SKI", p.fn);
		goto out;
	}

	if (!ta && p.res->aki == NULL) {
		warnx("%s: RFC 6487 section 8.4.2: "
		    "non-trust anchor missing AKI", p.fn);
		goto out;
	} else if (!ta && strcmp(p.res->aki, p.res->ski) == 0) {
		warnx("%s: RFC 6487 section 8.4.2: "
		    "non-trust anchor AKI may not match SKI", p.fn);
		goto out;
	}

	if (ta && p.res->crl != NULL) {
		warnx("%s: RFC 6487 section 8.4.2: "
		    "trust anchor may not specify CRL resource", p.fn);
		goto out;
	}

	if (p.res->asz == 0 && p.res->ipsz == 0) {
		warnx("%s: RFC 6487 section 4.8.10 and 4.8.11: "
		    "missing IP or AS resources", p.fn);
		goto out;
	}

	if (p.res->mft == NULL) {
		warnx("%s: RFC 6487 section 4.8.8: "
		    "missing SIA", p.fn);
		goto out;
	}
	if (X509_up_ref(x) == 0)
		errx(1, "king bula");

	p.res->x509 = x;

	rc = 1;
out:
	BIO_free_all(bio);
	if (rc == 0) {
		cert_free(p.res);
		X509_free(x);
		*xp = NULL;
	}
	return (rc == 0) ? NULL : p.res;
}

struct cert *
cert_parse(X509 **xp, const char *fn, const unsigned char *dgst)
{

	return cert_parse_inner(xp, fn, dgst, 0);
}

struct cert *
ta_parse(X509 **xp, const char *fn, const unsigned char *pkey, size_t pkeysz)
{
	EVP_PKEY	*pk = NULL, *opk = NULL;
	struct cert	*p;
	int		 rc = 0;

	if ((p = cert_parse_inner(xp, fn, NULL, 1)) == NULL)
		return NULL;

	if (pkey != NULL) {
		assert(*xp != NULL);
		pk = d2i_PUBKEY(NULL, &pkey, pkeysz);
		assert(pk != NULL);

		if ((opk = X509_get_pubkey(*xp)) == NULL)
			cryptowarnx("%s: RFC 6487 (trust anchor): "
			    "missing pubkey", fn);
		else if (!EVP_PKEY_cmp(pk, opk))
			cryptowarnx("%s: RFC 6487 (trust anchor): "
			    "pubkey does not match TAL pubkey", fn);
		else
			rc = 1;

		EVP_PKEY_free(pk);
		EVP_PKEY_free(opk);
	} else
		rc = 1;

	if (rc == 0) {
		cert_free(p);
		p = NULL;
		X509_free(*xp);
		*xp = NULL;
	}

	return p;
}

/*
 * Free parsed certificate contents.
 * Passing NULL is a noop.
 */
void
cert_free(struct cert *p)
{

	if (p == NULL)
		return;

	free(p->crl);
	free(p->mft);
	free(p->ips);
	free(p->as);
	free(p->aki);
	free(p->ski);
	X509_free(p->x509);
	free(p);
}

static void
cert_ip_buffer(char **b, size_t *bsz,
	size_t *bmax, const struct cert_ip *p)
{

	io_simple_buffer(b, bsz, bmax, &p->afi, sizeof(enum afi));
	io_simple_buffer(b, bsz, bmax, &p->type, sizeof(enum cert_ip_type));

	if (p->type != CERT_IP_INHERIT) {
		io_simple_buffer(b, bsz, bmax, &p->min, sizeof(p->min));
		io_simple_buffer(b, bsz, bmax, &p->max, sizeof(p->max));
	}

	if (p->type == CERT_IP_RANGE)
		ip_addr_range_buffer(b, bsz, bmax, &p->range);
	else if (p->type == CERT_IP_ADDR)
		ip_addr_buffer(b, bsz, bmax, &p->ip);
}

static void
cert_as_buffer(char **b, size_t *bsz,
	size_t *bmax, const struct cert_as *p)
{

	io_simple_buffer(b, bsz, bmax, &p->type, sizeof(enum cert_as_type));
	if (p->type == CERT_AS_RANGE) {
		io_simple_buffer(b, bsz, bmax, &p->range.min, sizeof(uint32_t));
		io_simple_buffer(b, bsz, bmax, &p->range.max, sizeof(uint32_t));
	} else if (p->type == CERT_AS_ID)
		io_simple_buffer(b, bsz, bmax, &p->id, sizeof(uint32_t));
}

/*
 * Write certificate parsed content into buffer.
 * See cert_read() for the other side of the pipe.
 */
void
cert_buffer(char **b, size_t *bsz, size_t *bmax, const struct cert *p)
{
	size_t	 i;
	int	 has_crl, has_aki;

	io_simple_buffer(b, bsz, bmax, &p->valid, sizeof(int));
	io_simple_buffer(b, bsz, bmax, &p->ipsz, sizeof(size_t));
	for (i = 0; i < p->ipsz; i++)
		cert_ip_buffer(b, bsz, bmax, &p->ips[i]);

	io_simple_buffer(b, bsz, bmax, &p->asz, sizeof(size_t));
	for (i = 0; i < p->asz; i++)
		cert_as_buffer(b, bsz, bmax, &p->as[i]);

	io_str_buffer(b, bsz, bmax, p->mft);

	has_crl = (p->crl != NULL);
	io_simple_buffer(b, bsz, bmax, &has_crl, sizeof(int));
	if (has_crl)
		io_str_buffer(b, bsz, bmax, p->crl);
	has_aki = (p->aki != NULL);
	io_simple_buffer(b, bsz, bmax, &has_aki, sizeof(int));
	if (has_aki)
		io_str_buffer(b, bsz, bmax, p->aki);
	io_str_buffer(b, bsz, bmax, p->ski);
}

static void
cert_ip_read(int fd, struct cert_ip *p)
{

	io_simple_read(fd, &p->afi, sizeof(enum afi));
	io_simple_read(fd, &p->type, sizeof(enum cert_ip_type));

	if (p->type != CERT_IP_INHERIT) {
		io_simple_read(fd, &p->min, sizeof(p->min));
		io_simple_read(fd, &p->max, sizeof(p->max));
	}

	if (p->type == CERT_IP_RANGE)
		ip_addr_range_read(fd, &p->range);
	else if (p->type == CERT_IP_ADDR)
		ip_addr_read(fd, &p->ip);
}

static void
cert_as_read(int fd, struct cert_as *p)
{

	io_simple_read(fd, &p->type, sizeof(enum cert_as_type));
	if (p->type == CERT_AS_RANGE) {
		io_simple_read(fd, &p->range.min, sizeof(uint32_t));
		io_simple_read(fd, &p->range.max, sizeof(uint32_t));
	} else if (p->type == CERT_AS_ID)
		io_simple_read(fd, &p->id, sizeof(uint32_t));
}

/*
 * Allocate and read parsed certificate content from descriptor.
 * The pointer must be freed with cert_free().
 * Always returns a valid pointer.
 */
struct cert *
cert_read(int fd)
{
	struct cert	*p;
	size_t		 i;
	int		 has_crl, has_aki;

	if ((p = calloc(1, sizeof(struct cert))) == NULL)
		err(1, NULL);

	io_simple_read(fd, &p->valid, sizeof(int));
	io_simple_read(fd, &p->ipsz, sizeof(size_t));
	p->ips = calloc(p->ipsz, sizeof(struct cert_ip));
	if (p->ips == NULL)
		err(1, NULL);
	for (i = 0; i < p->ipsz; i++)
		cert_ip_read(fd, &p->ips[i]);

	io_simple_read(fd, &p->asz, sizeof(size_t));
	p->as = calloc(p->asz, sizeof(struct cert_as));
	if (p->as == NULL)
		err(1, NULL);
	for (i = 0; i < p->asz; i++)
		cert_as_read(fd, &p->as[i]);

	io_str_read(fd, &p->mft);
	io_simple_read(fd, &has_crl, sizeof(int));
	if (has_crl)
		io_str_read(fd, &p->crl);
	io_simple_read(fd, &has_aki, sizeof(int));
	if (has_aki)
		io_str_read(fd, &p->aki);
	io_str_read(fd, &p->ski);

	return p;
}

struct auth *
auth_find(struct auth_tree *auths, const char *aki)
{
	struct auth a;
	struct cert c;

	/* we look up the cert where the ski == aki */
	c.ski = (char *)aki;
	a.cert = &c;

	return RB_FIND(auth_tree, auths, &a);
}

static inline int
authcmp(struct auth *a, struct auth *b)
{
	return strcmp(a->cert->ski, b->cert->ski);
}

RB_GENERATE(auth_tree, auth, entry, authcmp);