Adding upstream version 3.7.10.upstream/3.7.10

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1357 insertions, 0 deletions

diff --git a/src/tls/tls_dane.c b/src/tls/tls_dane.c
new file mode 100644
index 0000000..a2b9b80
--- /dev/null
+++ b/src/tls/tls_dane.c
@@ -0,0 +1,1357 @@
+/*++
+/* NAME
+/*	tls_dane 3
+/* SUMMARY
+/*	Support for RFC 6698, 7671, 7672 (DANE) certificate matching
+/* SYNOPSIS
+/*	#include <tls.h>
+/*
+/*	void tls_dane_loglevel(log_param, log_level);
+/*	const char *log_param;
+/*	const char *log_level;
+/*
+/*	int	tls_dane_avail()
+/*
+/*	void	tls_dane_flush()
+/*
+/*	TLS_DANE *tls_dane_alloc()
+/*
+/*      void    tls_tlsa_free(tlsa)
+/*      TLS_TLSA *tlsa;
+/*
+/*	void	tls_dane_free(dane)
+/*	TLS_DANE *dane;
+/*
+/*	void	tls_dane_add_fpt_digests(dane, digest, delim, smtp_mode)
+/*	TLS_DANE *dane;
+/*	const char *digest;
+/*	const char *delim;
+/*	int     smtp_mode;
+/*
+/*	TLS_TLSA *tlsa_prepend(tlsa, usage, selector, mtype, data, len)
+/*	TLS_TLSA *tlsa;
+/*	uint8_t usage;
+/*	uint8_t selector;
+/*	uint8_t mtype;
+/*	const unsigned char *data;
+/*	uint16_t length;
+/*
+/*	int	tls_dane_load_trustfile(dane, tafile)
+/*	TLS_DANE *dane;
+/*	const char *tafile;
+/*
+/*	TLS_DANE *tls_dane_resolve(port, proto, hostrr, forcetlsa)
+/*	unsigned port;
+/*	const char *proto;
+/*	DNS_RR *hostrr;
+/*	int	forcetlsa;
+/*
+/*	void	tls_dane_digest_init(ctx, fpt_alg)
+/*	SSL_CTX *ctx;
+/*	const EVP_MD *fpt_alg;
+/*
+/*	void	tls_dane_enable(TLScontext)
+/*	TLS_SESS_STATE *TLScontext;
+/*
+/*	void    tls_dane_log(TLScontext)
+/*	TLS_SESS_STATE *TLScontext;
+/*
+/*	int	tls_dane_unusable(dane)
+/*	const TLS_DANE *dane;
+/*
+/*	int	tls_dane_notfound(dane)
+/*	const TLS_DANE *dane;
+/* DESCRIPTION
+/*	tls_dane_loglevel() allows the policy lookup functions in the DANE
+/*	library to examine the application's TLS loglevel in and possibly
+/*	produce a more detailed activity log.
+/*
+/*	tls_dane_avail() returns true if the features required to support DANE
+/*	are present in libresolv.
+/*
+/*	tls_dane_flush() flushes all entries from the cache, and deletes
+/*	the cache.
+/*
+/*	tls_dane_alloc() returns a pointer to a newly allocated TLS_DANE
+/*	structure with null ta and ee digest sublists.
+/*
+/*	tls_tlsa_free() frees a TLSA record linked list.
+/*
+/*	tls_dane_free() frees the structure allocated by tls_dane_alloc().
+/*
+/*	tls_dane_digest_init() configures OpenSSL to support the configured
+/*	DANE TLSA digests and private-use fingerprint digest.
+/*
+/*	tlsa_prepend() prepends a TLSA record to the head of a linked list
+/*	which may be null when the list is empty. The result value is the
+/*	new list head.
+/*
+/*	tls_dane_add_fpt_digests() splits "digest" using the characters in
+/*	"delim" as delimiters and generates corresponding synthetic DANE TLSA
+/*	records with matching type 255 (private-use), which we associated with
+/*	the configured fingerprint digest algorithm.  This is an incremental
+/*	interface, that builds a TLS_DANE structure outside the cache by
+/*	manually adding entries.
+/*
+/*	tls_dane_load_trustfile() imports trust-anchor certificates and
+/*	public keys from a file (rather than DNS TLSA records).
+/*
+/*	tls_dane_resolve() maps a (port, protocol, hostrr) tuple to a
+/*	corresponding TLS_DANE policy structure found in the DNS.  The port
+/*	argument is in network byte order.  A null pointer is returned when
+/*	the DNS query for the TLSA record tempfailed.  In all other cases the
+/*	return value is a pointer to the corresponding TLS_DANE structure.
+/*	The caller must free the structure via tls_dane_free().
+/*
+/*	tls_dane_enable() enables DANE-style certificate checks for connections
+/*	that are configured with TLSA records.  The TLSA records may be from
+/*	DNS (at the "dane", "dane-only" and "half-dane" security levels), or be
+/*	synthetic in support of either the "fingerprint" level or local trust
+/*	anchor based validation with the "secure" and "verify" levels.  The
+/*	return value is the number of "usable" TLSA records loaded, or negative
+/*	if a record failed to load due to an internal OpenSSL problems, rather
+/*	than an issue with the record making that record "unusable".
+/*
+/*	tls_dane_log() logs successful verification via DNS-based or
+/*	synthetic DANE TLSA RRs (fingerprint or "tafile").
+/*
+/*	tls_dane_unusable() checks whether a cached TLS_DANE record is
+/*	the result of a validated RRset, with no usable elements.  In
+/*	this case, TLS is mandatory, but certificate verification is
+/*	not DANE-based.
+/*
+/*	tls_dane_notfound() checks whether a cached TLS_DANE record is
+/*	the result of a validated DNS lookup returning NODATA. In
+/*	this case, TLS is not required by RFC, though users may elect
+/*	a mandatory TLS fallback policy.
+/*
+/*	Arguments:
+/* .IP  ctx
+/*	SSL context to be configured with the chosen digest algorithms.
+/* .IP  fpt_alg
+/*	The OpenSSL EVP digest algorithm handle for the fingerprint digest.
+/* .IP  tlsa
+/*	TLSA record linked list head, initially NULL.
+/* .IP  usage
+/*	DANE TLSA certificate usage field.
+/* .IP  selector
+/*	DANE TLSA selector field.
+/* .IP  mtype
+/*	DANE TLSA matching type field
+/* .IP  data
+/*	DANE TLSA associated data field (raw binary form), copied for internal
+/*	use.  The caller is responsible for freeing his own copy.
+/* .IP  length
+/*	Length of DANE TLSA associated DATA field.
+/* .IP dane
+/*	Pointer to a TLS_DANE structure that lists the valid trust-anchor
+/*	and end-entity full-certificate and/or public-key digests.
+/* .IP port
+/*	The TCP port in network byte order.
+/* .IP proto
+/*	Almost certainly "tcp".
+/* .IP hostrr
+/*	DNS_RR pointer to TLSA base domain data.
+/* .IP forcetlsa
+/*	When true, TLSA lookups are performed even when the qname and rname
+/*	are insecure.  This is only useful in the unlikely case that DLV is
+/*	used to secure the TLSA RRset in an otherwise insecure zone.
+/* .IP log_param
+/*	The TLS log level parameter name whose value is the log_level argument.
+/* .IP log_level
+/*	The application TLS log level, which may affect dane lookup verbosity.
+/* .IP digest
+/*	The digest (or list of digests concatenated with characters from
+/*	"delim") to be added to the TLS_DANE record.
+/* .IP delim
+/*	The set of delimiter characters used above.
+/* .IP smtp_mode
+/*	Is the caller an SMTP client or an LMTP client?
+/* .IP tafile;
+/*	A file with trust anchor certificates or public keys in PEM format.
+/* LICENSE
+/* .ad
+/* .fi
+/*	This software is free. You can do with it whatever you want.
+/*	The original author kindly requests that you acknowledge
+/*	the use of his software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*
+/*	Viktor Dukhovni
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <ctype.h>
+
+#ifdef STRCASECMP_IN_STRINGS_H
+#include <strings.h>
+#endif
+
+#ifdef USE_TLS
+#include <string.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <mymalloc.h>
+#include <stringops.h>
+#include <midna_domain.h>
+#include <vstring.h>
+#include <events.h>			/* event_time() */
+#include <timecmp.h>
+#include <ctable.h>
+#include <hex_code.h>
+#include <safe_ultostr.h>
+#include <split_at.h>
+#include <name_code.h>
+
+#define STR(x)	vstring_str(x)
+
+/* Global library */
+
+#include <mail_params.h>
+
+/* DNS library. */
+
+#include <dns.h>
+
+/* TLS library. */
+
+#define TLS_INTERNAL
+#include <tls.h>
+
+/* Application-specific. */
+
+#undef DANE_TLSA_SUPPORT
+
+#if RES_USE_DNSSEC && RES_USE_EDNS0
+#define DANE_TLSA_SUPPORT
+static int dane_tlsa_support = 1;
+
+#else
+static int dane_tlsa_support = 0;
+
+#endif
+
+/*
+ * A NULL alg field disables the algorithm at the codepoint passed to the
+ * SSL_CTX_dane_mtype_set(3) function.  The ordinals are used for digest
+ * agility, higher is "better" (presumed stronger).
+ */
+typedef struct dane_mtype {
+    const EVP_MD *alg;
+    uint8_t ord;
+} dane_mtype;
+
+/*
+ * This is not intended to be a long-term cache of pre-parsed TLSA data,
+ * rather we primarily want to avoid fetching and parsing the TLSA records
+ * for a single multi-homed MX host more than once per delivery. Therefore,
+ * we keep the table reasonably small.
+ */
+#define CACHE_SIZE 20
+static CTABLE *dane_cache;
+
+static int log_mask;
+
+/* tls_dane_logmask - configure policy lookup logging */
+
+void    tls_dane_loglevel(const char *log_param, const char *log_level)
+{
+    log_mask = tls_log_mask(log_param, log_level);
+}
+
+/* tls_dane_avail - check for availability of dane required digests */
+
+int     tls_dane_avail(void)
+{
+    return (dane_tlsa_support);
+}
+
+/* tls_dane_alloc - allocate a TLS_DANE structure */
+
+TLS_DANE *tls_dane_alloc(void)
+{
+    TLS_DANE *dane = (TLS_DANE *) mymalloc(sizeof(*dane));
+
+    dane->tlsa = 0;
+    dane->base_domain = 0;
+    dane->flags = 0;
+    dane->expires = 0;
+    dane->refs = 1;
+    return (dane);
+}
+
+/* tls_tlsa_free - free a TLSA RR linked list */
+
+void    tls_tlsa_free(TLS_TLSA *tlsa)
+{
+    TLS_TLSA *next;
+
+    for (; tlsa; tlsa = next) {
+	next = tlsa->next;
+	myfree(tlsa->data);
+	myfree(tlsa);
+    }
+}
+
+/* tls_dane_free - free a TLS_DANE structure */
+
+void    tls_dane_free(TLS_DANE *dane)
+{
+    if (--dane->refs > 0)
+	return;
+    if (dane->base_domain)
+	myfree(dane->base_domain);
+    if (dane->tlsa)
+	tls_tlsa_free(dane->tlsa);
+    myfree((void *) dane);
+}
+
+/* tlsa_prepend - Prepend internal-form TLSA record to the RRset linked list */
+
+TLS_TLSA *tlsa_prepend(TLS_TLSA *tlsa, uint8_t usage, uint8_t selector,
+		               uint8_t mtype, const unsigned char *data,
+		               uint16_t data_len)
+{
+    TLS_TLSA *head;
+
+    head = (TLS_TLSA *) mymalloc(sizeof(*head));
+    head->usage = usage;
+    head->selector = selector;
+    head->mtype = mtype;
+    head->length = data_len;
+    head->data = (unsigned char *) mymemdup(data, data_len);
+    head->next = tlsa;
+    return (head);
+}
+
+#define MAX_HEAD_BYTES 32
+#define MAX_TAIL_BYTES 32
+#define MAX_DUMP_BYTES (MAX_HEAD_BYTES + MAX_TAIL_BYTES)
+
+/* tlsa_info - log import of a particular TLSA record */
+
+static void tlsa_info(const char *tag, const char *msg,
+		              uint8_t u, uint8_t s, uint8_t m,
+		              const unsigned char *data, ssize_t dlen)
+{
+    static VSTRING *top;
+    static VSTRING *bot;
+
+    if (top == 0)
+	top = vstring_alloc(2 * MAX_HEAD_BYTES);
+    if (bot == 0)
+	bot = vstring_alloc(2 * MAX_TAIL_BYTES);
+
+    if (dlen > MAX_DUMP_BYTES) {
+	hex_encode(top, (char *) data, MAX_HEAD_BYTES);
+	hex_encode(bot, (char *) data + dlen - MAX_TAIL_BYTES, MAX_TAIL_BYTES);
+    } else if (dlen > 0) {
+	hex_encode(top, (char *) data, dlen);
+    } else {
+	vstring_sprintf(top, "...");
+    }
+
+    msg_info("%s: %s: %u %u %u %s%s%s", tag, msg, u, s, m, STR(top),
+	     dlen > MAX_DUMP_BYTES ? "..." : "",
+	     dlen > MAX_DUMP_BYTES ? STR(bot) : "");
+}
+
+/* tlsa_carp - carp about a particular TLSA record */
+
+static void tlsa_carp(const char *s1, const char *s2, const char *s3,
+		            const char *s4, uint8_t u, uint8_t s, uint8_t m,
+		              const unsigned char *data, ssize_t dlen)
+{
+    static VSTRING *top;
+    static VSTRING *bot;
+
+    if (top == 0)
+	top = vstring_alloc(2 * MAX_HEAD_BYTES);
+    if (bot == 0)
+	bot = vstring_alloc(2 * MAX_TAIL_BYTES);
+
+    if (dlen > MAX_DUMP_BYTES) {
+	hex_encode(top, (char *) data, MAX_HEAD_BYTES);
+	hex_encode(bot, (char *) data + dlen - MAX_TAIL_BYTES, MAX_TAIL_BYTES);
+    } else if (dlen > 0) {
+	hex_encode(top, (char *) data, dlen);
+    } else {
+	vstring_sprintf(top, "...");
+    }
+
+    msg_warn("%s%s%s %s: %u %u %u %s%s%s", s1, s2, s3, s4, u, s, m, STR(top),
+	     dlen > MAX_DUMP_BYTES ? "..." : "",
+	     dlen > MAX_DUMP_BYTES ? STR(bot) : "");
+}
+
+/* tls_dane_flush - flush the cache */
+
+void    tls_dane_flush(void)
+{
+    if (dane_cache)
+	ctable_free(dane_cache);
+    dane_cache = 0;
+}
+
+/* dane_free - ctable style */
+
+static void dane_free(void *dane, void *unused_context)
+{
+    tls_dane_free((TLS_DANE *) dane);
+}
+
+/* tls_dane_add_fpt_digests - map fingerprint list to DANE TLSA RRset */
+
+void    tls_dane_add_fpt_digests(TLS_DANE *dane, const char *digest,
+				         const char *delim, int smtp_mode)
+{
+    ARGV   *values = argv_split(digest, delim);
+    ssize_t i;
+
+    if (smtp_mode) {
+	if (warn_compat_break_smtp_tls_fpt_dgst)
+	    msg_info("using backwards-compatible default setting "
+		     VAR_SMTP_TLS_FPT_DGST "=md5 to compute certificate "
+		     "fingerprints");
+    } else {
+	if (warn_compat_break_lmtp_tls_fpt_dgst)
+	    msg_info("using backwards-compatible default setting "
+		     VAR_LMTP_TLS_FPT_DGST "=md5 to compute certificate "
+		     "fingerprints");
+    }
+
+    for (i = 0; i < values->argc; ++i) {
+	const char *cp = values->argv[i];
+	size_t  ilen = strlen(cp);
+	VSTRING *raw;
+
+	/*
+	 * Decode optionally colon-separated hex-encoded string, the input
+	 * value requires at most 3 bytes per byte of payload, which must not
+	 * exceed the size of the widest supported hash function.
+	 */
+	if (ilen > 3 * EVP_MAX_MD_SIZE) {
+	    msg_warn("malformed fingerprint value: %.100s...",
+		     values->argv[i]);
+	    continue;
+	}
+	raw = vstring_alloc(ilen / 2);
+	if (hex_decode_opt(raw, cp, ilen, HEX_DECODE_FLAG_ALLOW_COLON) == 0) {
+	    myfree(raw);
+	    msg_warn("malformed fingerprint value: %.384s", values->argv[i]);
+	    continue;
+	}
+
+	/*
+	 * At the "fingerprint" security level certificate digests and public
+	 * key digests are interchangeable.  Each leaf certificate is matched
+	 * via either the public key digest or full certificate digest.  The
+	 * DER encoding of a certificate is not a valid public key, and
+	 * conversely, the DER encoding of a public key is not a valid
+	 * certificate.  An attacker would need a 2nd-preimage that is
+	 * feasible across types (given cert digest == some pkey digest) and
+	 * yet presumably difficult within a type (e.g. given cert digest ==
+	 * some other cert digest).  No such attacks are known at this time,
+	 * and it is expected that if any are found they would work within as
+	 * well as across the cert/pkey data types.
+	 * 
+	 * The private-use matching type "255" is mapped to the configured
+	 * fingerprint digest, which may (harmlessly) coincide with one of
+	 * the standard DANE digest algorithms.  The private code point is
+	 * however unconditionally enabled.
+	 */
+	if (log_mask & (TLS_LOG_VERBOSE | TLS_LOG_DANE))
+	    tlsa_info("fingerprint", "digest as private-use TLSA record",
+		   3, 0, 255, (unsigned char *) STR(raw), VSTRING_LEN(raw));
+	dane->tlsa = tlsa_prepend(dane->tlsa, 3, 0, 255,
+			      (unsigned char *) STR(raw), VSTRING_LEN(raw));
+	dane->tlsa = tlsa_prepend(dane->tlsa, 3, 1, 255,
+			      (unsigned char *) STR(raw), VSTRING_LEN(raw));
+	vstring_free(raw);
+    }
+    argv_free(values);
+}
+
+/* parse_tlsa_rr - parse a validated TLSA RRset */
+
+static int parse_tlsa_rr(TLS_DANE *dane, DNS_RR *rr)
+{
+    const uint8_t *ip;
+    uint8_t usage;
+    uint8_t selector;
+    uint8_t mtype;
+    ssize_t dlen;
+    unsigned const char *data;
+    int     iscname = strcasecmp(rr->rname, rr->qname);
+    const char *q = iscname ? rr->qname : "";
+    const char *a = iscname ? " -> " : "";
+    const char *r = rr->rname;
+
+    if (rr->type != T_TLSA)
+	msg_panic("%s%s%s: unexpected non-TLSA RR type: %u",
+		  q, a, r, rr->type);
+
+    /* Drop truncated records */
+    if ((dlen = rr->data_len - 3) < 0) {
+	msg_warn("%s%s%s: truncated TLSA RR length == %u",
+		 q, a, r, (unsigned) rr->data_len);
+	return (0);
+    }
+    ip = (const uint8_t *) rr->data;
+    usage = *ip++;
+    selector = *ip++;
+    mtype = *ip++;
+    data = (const unsigned char *) ip;
+
+    /*-
+     * Drop unsupported usages.
+     * Note: NO SUPPORT for usages 0/1 which do not apply to SMTP.
+     */
+    switch (usage) {
+    case DNS_TLSA_USAGE_TRUST_ANCHOR_ASSERTION:
+    case DNS_TLSA_USAGE_DOMAIN_ISSUED_CERTIFICATE:
+	break;
+    default:
+	tlsa_carp(q, a, r, "unsupported TLSA certificate usage",
+		  usage, selector, mtype, data, dlen);
+	return (0);
+    }
+
+    /*
+     * Drop private-use matching type, reserved for fingerprint matching.
+     */
+    if (mtype == 255) {
+	tlsa_carp(q, a, r, "reserved private-use matching type",
+		  usage, selector, mtype, data, dlen);
+	return (0);
+    }
+    if (log_mask & (TLS_LOG_VERBOSE | TLS_LOG_DANE))
+	tlsa_info("DNSSEC-signed TLSA record", r,
+		  usage, selector, mtype, data, dlen);
+    dane->tlsa = tlsa_prepend(dane->tlsa, usage, selector, mtype, data, dlen);
+    return (1);
+}
+
+/* dane_lookup - TLSA record lookup, ctable style */
+
+static void *dane_lookup(const char *tlsa_fqdn, void *unused_ctx)
+{
+    static VSTRING *why = 0;
+    DNS_RR *rrs = 0;
+    DNS_RR *rr;
+    TLS_DANE *dane = tls_dane_alloc();
+    int     ret;
+
+    if (why == 0)
+	why = vstring_alloc(10);
+
+    ret = dns_lookup(tlsa_fqdn, T_TLSA, RES_USE_DNSSEC, &rrs, 0, why);
+
+    switch (ret) {
+    case DNS_OK:
+	if (TLS_DANE_CACHE_TTL_MIN && rrs->ttl < TLS_DANE_CACHE_TTL_MIN)
+	    rrs->ttl = TLS_DANE_CACHE_TTL_MIN;
+	if (TLS_DANE_CACHE_TTL_MAX && rrs->ttl > TLS_DANE_CACHE_TTL_MAX)
+	    rrs->ttl = TLS_DANE_CACHE_TTL_MAX;
+
+	/* One more second to account for discrete time */
+	dane->expires = 1 + event_time() + rrs->ttl;
+
+	if (rrs->dnssec_valid) {
+	    int     n = 0;
+
+	    for (rr = rrs; rr != 0; rr = rr->next)
+		n += parse_tlsa_rr(dane, rr);
+	    if (n == 0)
+		dane->flags |= TLS_DANE_FLAG_EMPTY;
+	} else
+	    dane->flags |= TLS_DANE_FLAG_NORRS;
+
+	if (rrs)
+	    dns_rr_free(rrs);
+	break;
+
+    case DNS_NOTFOUND:
+	dane->flags |= TLS_DANE_FLAG_NORRS;
+	dane->expires = 1 + event_time() + TLS_DANE_CACHE_TTL_MIN;
+	break;
+
+    default:
+	msg_warn("DANE TLSA lookup problem: %s", STR(why));
+	dane->flags |= TLS_DANE_FLAG_ERROR;
+	break;
+    }
+
+    return (void *) dane;
+}
+
+/* resolve_host - resolve TLSA RRs for hostname (rname or qname) */
+
+static TLS_DANE *resolve_host(const char *host, const char *proto,
+			              unsigned port)
+{
+    static VSTRING *query_domain;
+    TLS_DANE *dane;
+
+    if (query_domain == 0)
+	query_domain = vstring_alloc(64);
+
+    vstring_sprintf(query_domain, "_%u._%s.%s", ntohs(port), proto, host);
+    dane = (TLS_DANE *) ctable_locate(dane_cache, STR(query_domain));
+    if (timecmp(event_time(), dane->expires) > 0)
+	dane = (TLS_DANE *) ctable_refresh(dane_cache, STR(query_domain));
+    if (dane->base_domain == 0)
+	dane->base_domain = mystrdup(host);
+    /* Increment ref-count of cached entry */
+    ++dane->refs;
+    return (dane);
+}
+
+/* qname_secure - Lookup qname DNSSEC status */
+
+static int qname_secure(const char *qname)
+{
+    static VSTRING *why;
+    int     ret = 0;
+    DNS_RR *rrs;
+
+    if (!why)
+	why = vstring_alloc(10);
+
+    /*
+     * We assume that qname is already an fqdn, and does not need any
+     * suffixes from RES_DEFNAME or RES_DNSRCH.  This is typically the name
+     * of an MX host, and must be a complete DNS name.  DANE initialization
+     * code in the SMTP client is responsible for checking that the default
+     * resolver flags do not include RES_DEFNAME and RES_DNSRCH.
+     */
+    ret = dns_lookup(qname, T_CNAME, RES_USE_DNSSEC, &rrs, 0, why);
+    if (ret == DNS_OK) {
+	ret = rrs->dnssec_valid;
+	dns_rr_free(rrs);
+	return (ret);
+    }
+    if (ret == DNS_NOTFOUND)
+	vstring_sprintf(why, "no longer a CNAME");
+    msg_warn("DNSSEC status lookup error for %s: %s", qname, STR(why));
+    return (-1);
+}
+
+/* tls_dane_resolve - cached map: (name, proto, port) -> TLS_DANE */
+
+TLS_DANE *tls_dane_resolve(unsigned port, const char *proto, DNS_RR *hostrr,
+			           int forcetlsa)
+{
+    TLS_DANE *dane = 0;
+    int     iscname = strcasecmp(hostrr->rname, hostrr->qname);
+    int     isvalid = 1;
+
+    if (!tls_dane_avail())
+	return (0);				/* Error */
+
+    /*
+     * By default suppress TLSA lookups for hosts in non-DNSSEC zones.  If
+     * the host zone is not DNSSEC validated, the TLSA qname sub-domain is
+     * safely assumed to not be in a DNSSEC Look-aside Validation child zone.
+     */
+    if (!forcetlsa && !hostrr->dnssec_valid) {
+	isvalid = iscname ? qname_secure(hostrr->qname) : 0;
+	if (isvalid < 0)
+	    return (0);				/* Error */
+    }
+    if (!isvalid) {
+	dane = tls_dane_alloc();
+	dane->flags = TLS_DANE_FLAG_NORRS;
+    } else {
+	if (!dane_cache)
+	    dane_cache = ctable_create(CACHE_SIZE, dane_lookup, dane_free, 0);
+
+	/*
+	 * Try the rname first if secure, if nothing there, try the qname if
+	 * different.  Note, lookup errors are distinct from success with
+	 * nothing found.  If the rname lookup fails we don't try the qname.
+	 */
+	if (hostrr->dnssec_valid) {
+	    dane = resolve_host(hostrr->rname, proto, port);
+	    if (tls_dane_notfound(dane) && iscname) {
+		tls_dane_free(dane);
+		dane = 0;
+	    }
+	}
+	if (!dane)
+	    dane = resolve_host(hostrr->qname, proto, port);
+	if (dane->flags & TLS_DANE_FLAG_ERROR) {
+	    /* We don't return this object. */
+	    tls_dane_free(dane);
+	    dane = 0;
+	}
+    }
+
+    return (dane);
+}
+
+/* tls_dane_load_trustfile - load trust anchor certs or keys from file */
+
+int     tls_dane_load_trustfile(TLS_DANE *dane, const char *tafile)
+{
+    BIO    *bp;
+    char   *name = 0;
+    char   *header = 0;
+    unsigned char *data = 0;
+    long    len;
+    int     tacount;
+    char   *errtype = 0;		/* if error: cert or pkey? */
+
+    /* nop */
+    if (tafile == 0 || *tafile == 0)
+	return (1);
+
+    /*
+     * On each call, PEM_read() wraps a stdio file in a BIO_NOCLOSE bio,
+     * calls PEM_read_bio() and then frees the bio.  It is just as easy to
+     * open a BIO as a stdio file, so we use BIOs and call PEM_read_bio()
+     * directly.
+     */
+    if ((bp = BIO_new_file(tafile, "r")) == NULL) {
+	msg_warn("error opening trust anchor file: %s: %m", tafile);
+	return (0);
+    }
+    /* Don't report old news */
+    ERR_clear_error();
+
+    /*
+     * OpenSSL implements DANE strictly, with DANE-TA(2) only matching issuer
+     * certificates, and never the leaf cert.  We also allow the
+     * trust-anchors to directly match the leaf certificate or public key.
+     */
+    for (tacount = 0;
+	 errtype == 0 && PEM_read_bio(bp, &name, &header, &data, &len);
+	 ++tacount) {
+	uint8_t daneta = DNS_TLSA_USAGE_TRUST_ANCHOR_ASSERTION;
+	uint8_t daneee = DNS_TLSA_USAGE_DOMAIN_ISSUED_CERTIFICATE;
+	uint8_t mtype = DNS_TLSA_MATCHING_TYPE_NO_HASH_USED;
+
+	if (strcmp(name, PEM_STRING_X509) == 0
+	    || strcmp(name, PEM_STRING_X509_OLD) == 0) {
+	    uint8_t selector = DNS_TLSA_SELECTOR_FULL_CERTIFICATE;
+
+	    if (log_mask & (TLS_LOG_VERBOSE | TLS_LOG_DANE))
+		tlsa_info("TA cert as TLSA record", tafile,
+			  daneta, selector, mtype, data, len);
+	    dane->tlsa =
+		tlsa_prepend(dane->tlsa, daneta, selector, mtype, data, len);
+	    dane->tlsa =
+		tlsa_prepend(dane->tlsa, daneee, selector, mtype, data, len);
+	} else if (strcmp(name, PEM_STRING_PUBLIC) == 0) {
+	    uint8_t selector = DNS_TLSA_SELECTOR_SUBJECTPUBLICKEYINFO;
+
+	    if (log_mask & (TLS_LOG_VERBOSE | TLS_LOG_DANE))
+		tlsa_info("TA pkey as TLSA record", tafile,
+			  daneta, selector, mtype, data, len);
+	    dane->tlsa =
+		tlsa_prepend(dane->tlsa, daneta, selector, mtype, data, len);
+	    dane->tlsa = tlsa_prepend(dane->tlsa, daneee, selector, mtype, data, len);
+	}
+
+	/*
+	 * If any of these were null, PEM_read() would have failed.
+	 */
+	OPENSSL_free(name);
+	OPENSSL_free(header);
+	OPENSSL_free(data);
+    }
+    BIO_free(bp);
+
+    if (errtype) {
+	tls_print_errors();
+	msg_warn("error reading: %s: malformed trust-anchor %s",
+		 tafile, errtype);
+	return (0);
+    }
+    if (ERR_GET_REASON(ERR_peek_last_error()) == PEM_R_NO_START_LINE) {
+	/* Reached end of PEM file */
+	ERR_clear_error();
+	return (tacount > 0);
+    }
+    /* Some other PEM read error */
+    tls_print_errors();
+    return (0);
+}
+
+int     tls_dane_enable(TLS_SESS_STATE *TLScontext)
+{
+    const TLS_DANE *dane = TLScontext->dane;
+    TLS_TLSA *tp;
+    SSL    *ssl = TLScontext->con;
+    int     usable = 0;
+    int     ret;
+
+    for (tp = dane->tlsa; tp != 0; tp = tp->next) {
+	ret = SSL_dane_tlsa_add(ssl, tp->usage, tp->selector,
+				tp->mtype, tp->data, tp->length);
+	if (ret > 0) {
+	    ++usable;
+	    continue;
+	}
+	if (ret == 0) {
+	    tlsa_carp(TLScontext->namaddr, ":", "", "unusable TLSA RR",
+		      tp->usage, tp->selector, tp->mtype, tp->data,
+		      tp->length);
+	    continue;
+	}
+	/* Internal problem in OpenSSL */
+	tlsa_carp(TLScontext->namaddr, ":", "", "error loading trust settings",
+		  tp->usage, tp->selector, tp->mtype, tp->data, tp->length);
+	tls_print_errors();
+	return (-1);
+    }
+    return (usable);
+}
+
+/* tls_dane_digest_init - configure supported DANE digests */
+
+void    tls_dane_digest_init(SSL_CTX *ctx, const EVP_MD *fpt_alg)
+{
+    dane_mtype mtypes[256];
+    char   *cp;
+    char   *save;
+    char   *algname;
+    uint8_t m;
+    uint8_t ord = 0;
+    uint8_t maxtype;
+
+    memset((char *) mtypes, 0, sizeof(mtypes));
+
+    /*
+     * The DANE SHA2-256(1) and SHA2-512(2) algorithms are disabled, unless
+     * explicitly enabled.  Other codepoints can be disabled explicitly by
+     * giving them an empty digest name, which also implicitly disables all
+     * smaller codepoints that are not explicitly assigned.
+     * 
+     * We reserve the private-use code point (255) for use with fingerprint
+     * matching.  It MUST NOT be accepted in DNS replies.
+     */
+    mtypes[1].alg = NULL;
+    mtypes[2].alg = NULL;
+    mtypes[255].alg = fpt_alg;
+    maxtype = 2;
+
+    save = cp = mystrdup(var_tls_dane_digests);
+    while ((algname = mystrtok(&cp, CHARS_COMMA_SP)) != 0) {
+	char   *algcode = split_at(algname, '=');
+	int     codepoint = -1;
+
+	if (algcode && *algcode) {
+	    unsigned long l;
+	    char   *endcp;
+
+	    /*
+	     * XXX: safe_strtoul() does not flag empty or white-space only
+	     * input.  Since we get algcode by splitting white-space/comma
+	     * delimited tokens, this is not a problem here.
+	     */
+	    l = safe_strtoul(algcode, &endcp, 10);
+	    if ((l == 0 && (errno == EINVAL || endcp == algcode))
+		|| l >= 255 || *endcp) {
+		msg_warn("Invalid matching type number in %s: %s=%s",
+			 VAR_TLS_DANE_DIGESTS, algname, algcode);
+		continue;
+	    }
+	    if (l == 0 || l == 255) {
+		msg_warn("Reserved matching type number in %s: %s=%s",
+			 VAR_TLS_DANE_DIGESTS, algname, algcode);
+		continue;
+	    }
+	    codepoint = l;
+	}
+	/* Disable any codepoint gaps */
+	if (codepoint > maxtype) {
+	    while (++maxtype < codepoint)
+		mtypes[codepoint].alg = NULL;
+	    maxtype = codepoint;
+	}
+	/* Handle explicitly disabled codepoints */
+	if (*algname == 0) {
+	    /* Skip empty specifiers */
+	    if (codepoint < 0)
+		continue;
+	    mtypes[codepoint].alg = NULL;
+	    continue;
+	}
+	switch (codepoint) {
+	case -1:
+	    if (strcasecmp(algname, LN_sha256) == 0)
+		codepoint = 1;			/* SHA2-256(1) */
+	    else if (strcasecmp(algname, LN_sha512) == 0)
+		codepoint = 2;			/* SHA2-512(2) */
+	    else {
+		msg_warn("%s: digest algorithm %s needs an explicit number",
+			 VAR_TLS_DANE_DIGESTS, algname);
+		continue;
+	    }
+	    break;
+	case 1:
+	    if (strcasecmp(algname, LN_sha256) != 0) {
+		msg_warn("%s: matching type 1 can only be %s",
+			 VAR_TLS_DANE_DIGESTS, LN_sha256);
+		continue;
+	    }
+	    algname = LN_sha256;
+	    break;
+	case 2:
+	    if (strcasecmp(algname, LN_sha512) != 0) {
+		msg_warn("%s: matching type 2 can only be %s",
+			 VAR_TLS_DANE_DIGESTS, LN_sha512);
+		continue;
+	    }
+	    algname = LN_sha512;
+	    break;
+	default:
+	    break;
+	}
+
+	if (mtypes[codepoint].ord != 0) {
+	    msg_warn("%s: matching type %d specified more than once",
+		     VAR_TLS_DANE_DIGESTS, codepoint);
+	    continue;
+	}
+	mtypes[codepoint].ord = ++ord;
+
+	if ((mtypes[codepoint].alg = tls_digest_byname(algname, NULL)) == 0) {
+	    msg_warn("%s: digest algorithm \"%s\"(%d) unknown",
+		     VAR_TLS_DANE_DIGESTS, algname, codepoint);
+	    continue;
+	}
+    }
+    myfree(save);
+
+    for (m = 1; m != 0; m = m != maxtype ? m + 1 : 255) {
+
+	/*
+	 * In OpenSSL higher order ordinals are preferred, but we list the
+	 * most preferred algorithms first, so the last ordinal becomes 1,
+	 * next-to-last, 2, ...
+	 * 
+	 * The ordinals of non-disabled algorithms are always positive, and the
+	 * computed value cannot overflow 254 (the largest possible value of
+	 * 'ord' after loading each valid codepoint at most once).
+	 */
+	if (SSL_CTX_dane_mtype_set(ctx, mtypes[m].alg, m,
+				   ord - mtypes[m].ord + 1) <= 0) {
+	    msg_warn("%s: error configuring matching type %d",
+		     VAR_TLS_DANE_DIGESTS, m);
+	    tls_print_errors();
+	}
+    }
+}
+
+/* tls_dane_log - log DANE-based verification success */
+
+void    tls_dane_log(TLS_SESS_STATE *TLScontext)
+{
+    static VSTRING *top;
+    static VSTRING *bot;
+    EVP_PKEY *mspki = 0;
+    int     depth = SSL_get0_dane_authority(TLScontext->con, NULL, &mspki);
+    uint8_t u, s, m;
+    unsigned const char *data;
+    size_t  dlen;
+
+    if (depth < 0)
+	return;					/* No DANE auth */
+
+    switch (TLScontext->level) {
+    case TLS_LEV_SECURE:
+    case TLS_LEV_VERIFY:
+	msg_info("%s: Matched trust anchor at depth %d",
+		 TLScontext->namaddr, depth);
+	return;
+    }
+
+    if (top == 0)
+	top = vstring_alloc(2 * MAX_HEAD_BYTES);
+    if (bot == 0)
+	bot = vstring_alloc(2 * MAX_TAIL_BYTES);
+
+    (void) SSL_get0_dane_tlsa(TLScontext->con, &u, &s, &m, &data, &dlen);
+    if (dlen > MAX_DUMP_BYTES) {
+	hex_encode(top, (char *) data, MAX_HEAD_BYTES);
+	hex_encode(bot, (char *) data + dlen - MAX_TAIL_BYTES, MAX_TAIL_BYTES);
+    } else {
+	hex_encode(top, (char *) data, dlen);
+    }
+
+    switch (TLScontext->level) {
+    case TLS_LEV_FPRINT:
+	msg_info("%s: Matched fingerprint: %s%s%s", TLScontext->namaddr,
+		 STR(top), dlen > MAX_DUMP_BYTES ? "..." : "",
+		 dlen > MAX_DUMP_BYTES ? STR(bot) : "");
+	return;
+
+    default:
+	msg_info("%s: Matched DANE %s at depth %d: %u %u %u %s%s%s",
+		 TLScontext->namaddr, mspki ?
+		 "TA public key verified certificate" : depth ?
+		 "TA certificate" : "EE certificate", depth, u, s, m,
+		 STR(top), dlen > MAX_DUMP_BYTES ? "..." : "",
+		 dlen > MAX_DUMP_BYTES ? STR(bot) : "");
+	return;
+    }
+}
+
+#ifdef TEST
+
+#include <unistd.h>
+#include <stdarg.h>
+
+#include <mail_params.h>
+#include <mail_conf.h>
+#include <msg_vstream.h>
+
+static int verify_chain(SSL *ssl, x509_stack_t *chain, TLS_SESS_STATE *tctx)
+{
+    int     ret;
+    X509   *cert;
+    X509_STORE_CTX *store_ctx;
+    SSL_CTX *ssl_ctx = SSL_get_SSL_CTX(ssl);
+    X509_STORE *store = SSL_CTX_get_cert_store(ssl_ctx);
+    int     store_ctx_idx = SSL_get_ex_data_X509_STORE_CTX_idx();
+
+    cert = sk_X509_value(chain, 0);
+    if ((store_ctx = X509_STORE_CTX_new()) == NULL) {
+	SSLerr(SSL_F_SSL_VERIFY_CERT_CHAIN, ERR_R_MALLOC_FAILURE);
+	return 0;
+    }
+    if (!X509_STORE_CTX_init(store_ctx, store, cert, chain)) {
+	X509_STORE_CTX_free(store_ctx);
+	return 0;
+    }
+    X509_STORE_CTX_set_ex_data(store_ctx, store_ctx_idx, ssl);
+
+    /* We're *verifying* a server chain */
+    X509_STORE_CTX_set_default(store_ctx, "ssl_server");
+    X509_VERIFY_PARAM_set1(X509_STORE_CTX_get0_param(store_ctx),
+			   SSL_get0_param(ssl));
+    X509_STORE_CTX_set0_dane(store_ctx, SSL_get0_dane(ssl));
+
+    ret = X509_verify_cert(store_ctx);
+
+    SSL_set_verify_result(ssl, X509_STORE_CTX_get_error(store_ctx));
+    X509_STORE_CTX_free(store_ctx);
+
+    return (ret);
+}
+
+static void load_tlsa_args(SSL *ssl, char *argv[])
+{
+    const EVP_MD *md = 0;
+    X509   *cert = 0;
+    BIO    *bp;
+    unsigned char *buf;
+    unsigned char *buf2;
+    int     len;
+    uint8_t u = atoi(argv[1]);
+    uint8_t s = atoi(argv[2]);
+    uint8_t m = atoi(argv[3]);
+    EVP_PKEY *pkey;
+
+    /* Unsupported usages are fatal */
+    switch (u) {
+    case DNS_TLSA_USAGE_TRUST_ANCHOR_ASSERTION:
+    case DNS_TLSA_USAGE_DOMAIN_ISSUED_CERTIFICATE:
+	break;
+    default:
+	msg_fatal("unsupported certificate usage %u", u);
+    }
+
+    /* Unsupported selectors are fatal */
+    switch (s) {
+    case DNS_TLSA_SELECTOR_FULL_CERTIFICATE:
+    case DNS_TLSA_SELECTOR_SUBJECTPUBLICKEYINFO:
+	break;
+    default:
+	msg_fatal("unsupported selector %u", s);
+    }
+
+    /* Unsupported selectors are fatal */
+    switch (m) {
+    case DNS_TLSA_MATCHING_TYPE_NO_HASH_USED:
+    case DNS_TLSA_MATCHING_TYPE_SHA256:
+    case DNS_TLSA_MATCHING_TYPE_SHA512:
+	break;
+    default:
+	msg_fatal("unsupported matching type %u", m);
+    }
+
+    if ((bp = BIO_new_file(argv[4], "r")) == NULL)
+	msg_fatal("error opening %s: %m", argv[4]);
+    if (!PEM_read_bio_X509(bp, &cert, 0, 0)) {
+	tls_print_errors();
+	msg_fatal("error loading certificate from %s: %m", argv[4]);
+    }
+    BIO_free(bp);
+
+    /*
+     * Extract ASN.1 DER form of certificate or public key.
+     */
+    switch (s) {
+    case DNS_TLSA_SELECTOR_FULL_CERTIFICATE:
+	len = i2d_X509(cert, NULL);
+	if (len > 0xffff)
+	    msg_fatal("certificate too long: %d", len);
+	buf2 = buf = (unsigned char *) mymalloc(len);
+	i2d_X509(cert, &buf2);
+	break;
+    case DNS_TLSA_SELECTOR_SUBJECTPUBLICKEYINFO:
+	pkey = X509_get_pubkey(cert);
+	len = i2d_PUBKEY(pkey, NULL);
+	if (len > 0xffff)
+	    msg_fatal("public key too long: %d", len);
+	buf2 = buf = (unsigned char *) mymalloc(len);
+	i2d_PUBKEY(pkey, &buf2);
+	EVP_PKEY_free(pkey);
+	break;
+    }
+    X509_free(cert);
+    OPENSSL_assert(buf2 - buf == len);
+
+    switch (m) {
+    case 0:
+	break;
+    case 1:
+	if ((md = tls_digest_byname(LN_sha256, NULL)) == 0)
+	    msg_fatal("Digest %s not found", LN_sha256);
+	break;
+    case 2:
+	if ((md = tls_digest_byname(LN_sha512, NULL)) == 0)
+	    msg_fatal("Digest %s not found", LN_sha512);
+	break;
+    default:
+	msg_fatal("Unsupported DANE mtype: %d", m);
+    }
+
+    if (md != 0) {
+	unsigned char mdbuf[EVP_MAX_MD_SIZE];
+	unsigned int mdlen = sizeof(mdbuf);
+
+	if (!EVP_Digest(buf, len, mdbuf, &mdlen, md, 0))
+	    msg_fatal("Digest failure for mtype: %d", m);
+	myfree(buf);
+	buf = (unsigned char *) mymemdup(mdbuf, len = mdlen);
+    }
+    SSL_dane_tlsa_add(ssl, u, s, m, buf, len);
+    myfree((void *) buf);
+}
+
+static x509_stack_t *load_chain(const char *chainfile)
+{
+    BIO    *bp;
+    char   *name = 0;
+    char   *header = 0;
+    unsigned char *data = 0;
+    long    len;
+    int     count;
+    char   *errtype = 0;		/* if error: cert or pkey? */
+    x509_stack_t *chain;
+    typedef X509 *(*d2i_X509_t) (X509 **, const unsigned char **, long);
+
+    if ((chain = sk_X509_new_null()) == 0) {
+	perror("malloc");
+	exit(1);
+    }
+
+    /*
+     * On each call, PEM_read() wraps a stdio file in a BIO_NOCLOSE bio,
+     * calls PEM_read_bio() and then frees the bio.  It is just as easy to
+     * open a BIO as a stdio file, so we use BIOs and call PEM_read_bio()
+     * directly.
+     */
+    if ((bp = BIO_new_file(chainfile, "r")) == NULL) {
+	fprintf(stderr, "error opening chainfile: %s: %m\n", chainfile);
+	exit(1);
+    }
+    /* Don't report old news */
+    ERR_clear_error();
+
+    for (count = 0;
+	 errtype == 0 && PEM_read_bio(bp, &name, &header, &data, &len);
+	 ++count) {
+	const unsigned char *p = data;
+
+	if (strcmp(name, PEM_STRING_X509) == 0
+	    || strcmp(name, PEM_STRING_X509_TRUSTED) == 0
+	    || strcmp(name, PEM_STRING_X509_OLD) == 0) {
+	    d2i_X509_t d;
+	    X509   *cert;
+
+	    d = strcmp(name, PEM_STRING_X509_TRUSTED) ? d2i_X509_AUX : d2i_X509;
+	    if ((cert = d(0, &p, len)) == 0 || (p - data) != len)
+		errtype = "certificate";
+	    else if (sk_X509_push(chain, cert) == 0) {
+		perror("malloc");
+		exit(1);
+	    }
+	} else {
+	    fprintf(stderr, "unexpected chain file object: %s\n", name);
+	    exit(1);
+	}
+
+	/*
+	 * If any of these were null, PEM_read() would have failed.
+	 */
+	OPENSSL_free(name);
+	OPENSSL_free(header);
+	OPENSSL_free(data);
+    }
+    BIO_free(bp);
+
+    if (errtype) {
+	tls_print_errors();
+	fprintf(stderr, "error reading: %s: malformed %s", chainfile, errtype);
+	exit(1);
+    }
+    if (ERR_GET_REASON(ERR_peek_last_error()) == PEM_R_NO_START_LINE) {
+	/* Reached end of PEM file */
+	ERR_clear_error();
+	if (count > 0)
+	    return chain;
+	fprintf(stderr, "no certificates found in: %s\n", chainfile);
+	exit(1);
+    }
+    /* Some other PEM read error */
+    tls_print_errors();
+    fprintf(stderr, "error reading: %s\n", chainfile);
+    exit(1);
+}
+
+static void usage(const char *progname)
+{
+    fprintf(stderr, "Usage: %s certificate-usage selector matching-type"
+	    " certfile \\\n\t\tCAfile chainfile hostname [certname ...]\n",
+	    progname);
+    fprintf(stderr, "  where, certificate-usage = TLSA certificate usage,\n");
+    fprintf(stderr, "\t selector = TLSA selector,\n");
+    fprintf(stderr, "\t matching-type = empty string or OpenSSL digest algorithm name,\n");
+    fprintf(stderr, "\t PEM certfile provides certificate association data,\n");
+    fprintf(stderr, "\t PEM CAfile contains any usage 0/1 trusted roots,\n");
+    fprintf(stderr, "\t PEM chainfile = server chain file to verify\n");
+    fprintf(stderr, "\t hostname = destination hostname,\n");
+    fprintf(stderr, "\t each certname augments the hostname for name checks.\n");
+    exit(1);
+}
+
+static SSL_CTX *ctx_init(const char *CAfile)
+{
+    SSL_CTX *client_ctx;
+
+    tls_param_init();
+    tls_check_version();
+
+    if (!tls_validate_digest(LN_sha1))
+	msg_fatal("%s digest algorithm not available", LN_sha1);
+
+    if (TLScontext_index < 0)
+	if ((TLScontext_index = SSL_get_ex_new_index(0, 0, 0, 0, 0)) < 0)
+	    msg_fatal("Cannot allocate SSL application data index");
+
+    ERR_clear_error();
+    if ((client_ctx = SSL_CTX_new(TLS_client_method())) == 0)
+	msg_fatal("cannot allocate client SSL_CTX");
+    SSL_CTX_set_verify_depth(client_ctx, 5);
+
+    /* Enable DANE support in OpenSSL */
+    if (SSL_CTX_dane_enable(client_ctx) <= 0) {
+	tls_print_errors();
+	msg_fatal("OpenSSL DANE initialization failed");
+    }
+    if (tls_set_ca_certificate_info(client_ctx, CAfile, "") < 0) {
+	tls_print_errors();
+	msg_fatal("cannot load CAfile: %s", CAfile);
+    }
+    SSL_CTX_set_verify(client_ctx, SSL_VERIFY_NONE,
+		       tls_verify_certificate_callback);
+    return (client_ctx);
+}
+
+int     main(int argc, char *argv[])
+{
+    SSL_CTX *ssl_ctx;
+    const EVP_MD *fpt_alg;
+    TLS_SESS_STATE *tctx;
+    x509_stack_t *chain;
+    int     i;
+
+    var_procname = mystrdup(basename(argv[0]));
+    set_mail_conf_str(VAR_PROCNAME, var_procname);
+    msg_vstream_init(var_procname, VSTREAM_OUT);
+
+    if (argc < 8)
+	usage(argv[0]);
+
+    ssl_ctx = ctx_init(argv[5]);
+    if (!tls_dane_avail())
+	msg_fatal("DANE TLSA support not available");
+
+    tctx = tls_alloc_sess_context(TLS_LOG_NONE, argv[7]);
+    tctx->namaddr = argv[7];
+    tctx->mdalg = LN_sha256;
+    tctx->dane = tls_dane_alloc();
+
+    if ((fpt_alg = tls_validate_digest(tctx->mdalg)) == 0)
+	msg_fatal("fingerprint digest algorithm %s not found",
+		  tctx->mdalg);
+    tls_dane_digest_init(ssl_ctx, fpt_alg);
+
+    if ((tctx->con = SSL_new(ssl_ctx)) == 0
+	|| !SSL_set_ex_data(tctx->con, TLScontext_index, tctx)) {
+	tls_print_errors();
+	msg_fatal("Error allocating SSL connection");
+    }
+    if (SSL_dane_enable(tctx->con, 0) <= 0) {
+	tls_print_errors();
+	msg_fatal("Error enabling DANE for SSL handle");
+    }
+    SSL_dane_set_flags(tctx->con, DANE_FLAG_NO_DANE_EE_NAMECHECKS);
+    SSL_dane_set_flags(tctx->con, X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS);
+    for (i = 7; i < argc; ++i)
+	if (!SSL_add1_host(tctx->con, argv[i]))
+	    msg_fatal("error adding hostname: %s", argv[i]);
+    load_tlsa_args(tctx->con, argv);
+    SSL_set_connect_state(tctx->con);
+
+    /* Verify saved server chain */
+    chain = load_chain(argv[6]);
+    i = verify_chain(tctx->con, chain, tctx);
+    tls_print_errors();
+
+    if (i > 0) {
+	const char *peername = SSL_get0_peername(tctx->con);
+
+	if (peername == 0)
+	    peername = argv[7];
+	msg_info("Verified %s", peername);
+    } else {
+	i = SSL_get_verify_result(tctx->con);
+	msg_info("certificate verification failed for %s:%s: num=%d:%s",
+		 argv[6], argv[7], i, X509_verify_cert_error_string(i));
+    }
+
+    return (i <= 0);
+}
+
+#endif					/* TEST */
+
+#endif					/* USE_TLS */