static void verify_extract_print(TLS_SESS_STATE *TLScontext, X509 *peercert,
const TLS_CLIENT_START_PROPS *props)
{
char **cpp;
/* Non-null by contract */
TLScontext->peer_fingerprint = tls_fingerprint(peercert, props->fpt_dgst);
if (props->tls_level != TLS_LEV_FPRINT)
return;
/*
* Compare the fingerprint against each acceptable value, ignoring
* upper/lower case differences.
*/
for (cpp = props->matchargv->argv; *cpp; ++cpp)
if (strcasecmp(TLScontext->peer_fingerprint, *cpp) == 0) {
TLScontext->peer_status |= TLS_CERT_FLAG_MATCHED;
break;
}
if (props->log_level >= 2)
acl_msg_info("%s %s%s fingerprint %s", props->namaddr,
TLS_CERT_IS_MATCHED(TLScontext) ? "Matched " : "",
props->fpt_dgst, TLScontext->peer_fingerprint);
}
/*
* This is the actual startup routine for the connection. We expect that the
* buffers are flushed and the "220 Ready to start TLS" was received by us,
* so that we can immediately start the TLS handshake process.
*/
TLS_SESS_STATE *tls_client_start(const TLS_CLIENT_START_PROPS *props)
{
int sts;
int protomask;
const char *cipher_list;
SSL_SESSION *session = 0;
SSL_CIPHER_const SSL_CIPHER *cipher;
X509 *peercert;
TLS_SESS_STATE *TLScontext;
TLS_APPL_STATE *app_ctx = props->ctx;
char *myserverid;
int log_mask = app_ctx->log_mask;
/*
* When certificate verification is required, log trust chain validation
* errors even when disabled by default for opportunistic sessions. For
* DANE this only applies when using trust-anchor associations.
*/
if (TLS_MUST_TRUST(props->tls_level)
&& (!TLS_DANE_BASED(props->tls_level) || TLS_DANE_HASTA(props->dane)))
log_mask |= TLS_LOG_UNTRUSTED;
if (log_mask & TLS_LOG_VERBOSE)
msg_info("setting up TLS connection to %s", props->namaddr);
/*
* First make sure we have valid protocol and cipher parameters
*
* Per-session protocol restrictions must be applied to the SSL connection,
* as restrictions in the global context cannot be cleared.
*/
protomask = tls_protocol_mask(props->protocols);
if (protomask == TLS_PROTOCOL_INVALID) {
/* tls_protocol_mask() logs no warning. */
msg_warn("%s: Invalid TLS protocol list \"%s\": aborting TLS session",
props->namaddr, props->protocols);
return (0);
}
/* DANE requires SSLv3 or later, not SSLv2. */
if (TLS_DANE_BASED(props->tls_level))
protomask |= TLS_PROTOCOL_SSLv2;
/*
* Per session cipher selection for sessions with mandatory encryption
*
* The cipherlist is applied to the global SSL context, since it is likely
* to stay the same between connections, so we make use of a 1-element
* cache to return the same result for identical inputs.
*/
cipher_list = tls_set_ciphers(app_ctx, "TLS", props->cipher_grade,
props->cipher_exclusions);
if (cipher_list == 0) {
msg_warn("%s: %s: aborting TLS session",
props->namaddr, vstring_str(app_ctx->why));
return (0);
}
if (log_mask & TLS_LOG_VERBOSE)
msg_info("%s: TLS cipher list \"%s\"", props->namaddr, cipher_list);
/*
* OpenSSL will ignore cached sessions that use the wrong protocol. So we
* do not need to filter out cached sessions with the "wrong" protocol,
* rather OpenSSL will simply negotiate a new session.
*
* We salt the session lookup key with the protocol list, so that sessions
* found in the cache are plausibly acceptable.
*
* By the time a TLS client is negotiating ciphers it has already offered to
* re-use a session, it is too late to renege on the offer. So we must
* not attempt to re-use sessions whose ciphers are too weak. We salt the
* session lookup key with the cipher list, so that sessions found in the
* cache are always acceptable.
*
* With DANE, (more generally any TLScontext where we specified explicit
* trust-anchor or end-entity certificates) the verification status of
* the SSL session depends on the specified list. Since we verify the
* certificate only during the initial handshake, we must segregate
* sessions with different TA lists. Note, that TA re-verification is
* not possible with cached sessions, since these don't hold the complete
* peer trust chain. Therefore, we compute a digest of the sorted TA
* parameters and append it to the serverid.
*/
myserverid = tls_serverid_digest(props, protomask, cipher_list);
/*
* Allocate a new TLScontext for the new connection and get an SSL
* structure. Add the location of TLScontext to the SSL to later retrieve
* the information inside the tls_verify_certificate_callback().
*
* If session caching was enabled when TLS was initialized, the cache type
* is stored in the client SSL context.
*/
TLScontext = tls_alloc_sess_context(log_mask, props->namaddr);
TLScontext->cache_type = app_ctx->cache_type;
TLScontext->serverid = myserverid;
TLScontext->stream = props->stream;
TLScontext->mdalg = props->mdalg;
/* Alias DANE digest info from props */
TLScontext->dane = props->dane;
if ((TLScontext->con = SSL_new(app_ctx->ssl_ctx)) == NULL) {
msg_warn("Could not allocate 'TLScontext->con' with SSL_new()");
tls_print_errors();
tls_free_context(TLScontext);
return (0);
}
if (!SSL_set_ex_data(TLScontext->con, TLScontext_index, TLScontext)) {
msg_warn("Could not set application data for 'TLScontext->con'");
tls_print_errors();
tls_free_context(TLScontext);
return (0);
}
/*
* Apply session protocol restrictions.
*/
if (protomask != 0)
SSL_set_options(TLScontext->con, TLS_SSL_OP_PROTOMASK(protomask));
/*
* XXX To avoid memory leaks we must always call SSL_SESSION_free() after
* calling SSL_set_session(), regardless of whether or not the session
* will be reused.
*/
if (TLScontext->cache_type) {
session = load_clnt_session(TLScontext);
if (session) {
SSL_set_session(TLScontext->con, session);
SSL_SESSION_free(session); /* 200411 */
}
}
#ifdef TLSEXT_MAXLEN_host_name
if (TLS_DANE_BASED(props->tls_level)
&& strlen(props->host) <= TLSEXT_MAXLEN_host_name) {
/*
* With DANE sessions, send an SNI hint. We don't care whether the
* server reports finding a matching certificate or not, so no
* callback is required to process the server response. Our use of
* SNI is limited to giving servers that are (mis)configured to use
* SNI the best opportunity to find the certificate they promised via
* the associated TLSA RRs. (Generally, server administrators should
* avoid SNI, and there are no plans to support SNI in the Postfix
* SMTP server).
*
* Since the hostname is DNSSEC-validated, it must be a DNS FQDN and
* thererefore valid for use with SNI. Failure to set a valid SNI
* hostname is a memory allocation error, and thus transient. Since
* we must not cache the session if we failed to send the SNI name,
* we have little choice but to abort.
*/
if (!SSL_set_tlsext_host_name(TLScontext->con, props->host)) {
msg_warn("%s: error setting SNI hostname to: %s", props->namaddr,
props->host);
tls_free_context(TLScontext);
return (0);
}
if (log_mask & TLS_LOG_DEBUG)
msg_info("%s: SNI hostname: %s", props->namaddr, props->host);
}
#endif
/*
* Before really starting anything, try to seed the PRNG a little bit
* more.
*/
tls_int_seed();
(void) tls_ext_seed(var_tls_daemon_rand_bytes);
/*
* Initialize the SSL connection to connect state. This should not be
* necessary anymore since 0.9.3, but the call is still in the library
* and maintaining compatibility never hurts.
*/
SSL_set_connect_state(TLScontext->con);
/*
* Connect the SSL connection with the network socket.
*/
if (SSL_set_fd(TLScontext->con, vstream_fileno(props->stream)) != 1) {
msg_info("SSL_set_fd error to %s", props->namaddr);
tls_print_errors();
uncache_session(app_ctx->ssl_ctx, TLScontext);
tls_free_context(TLScontext);
return (0);
}
/*
* Turn on non-blocking I/O so that we can enforce timeouts on network
* I/O.
*/
non_blocking(vstream_fileno(props->stream), NON_BLOCKING);
/*
* If the debug level selected is high enough, all of the data is dumped:
* TLS_LOG_TLSPKTS will dump the SSL negotiation, TLS_LOG_ALLPKTS will
* dump everything.
*
* We do have an SSL_set_fd() and now suddenly a BIO_ routine is called?
* Well there is a BIO below the SSL routines that is automatically
* created for us, so we can use it for debugging purposes.
*/
if (log_mask & TLS_LOG_TLSPKTS)
BIO_set_callback(SSL_get_rbio(TLScontext->con), tls_bio_dump_cb);
tls_dane_set_callback(app_ctx->ssl_ctx, TLScontext);
/*
* Start TLS negotiations. This process is a black box that invokes our
* call-backs for certificate verification.
*
* Error handling: If the SSL handhake fails, we print out an error message
* and remove all TLS state concerning this session.
*/
sts = tls_bio_connect(vstream_fileno(props->stream), props->timeout,
TLScontext);
if (sts <= 0) {
if (ERR_peek_error() != 0) {
msg_info("SSL_connect error to %s: %d", props->namaddr, sts);
tls_print_errors();
} else if (errno != 0) {
msg_info("SSL_connect error to %s: %m", props->namaddr);
} else {
msg_info("SSL_connect error to %s: lost connection",
props->namaddr);
}
uncache_session(app_ctx->ssl_ctx, TLScontext);
tls_free_context(TLScontext);
return (0);
}
/* Turn off packet dump if only dumping the handshake */
if ((log_mask & TLS_LOG_ALLPKTS) == 0)
BIO_set_callback(SSL_get_rbio(TLScontext->con), 0);
/*
* The caller may want to know if this session was reused or if a new
* session was negotiated.
*/
TLScontext->session_reused = SSL_session_reused(TLScontext->con);
if ((log_mask & TLS_LOG_CACHE) && TLScontext->session_reused)
msg_info("%s: Reusing old session", TLScontext->namaddr);
/*
* Do peername verification if requested and extract useful information
* from the certificate for later use.
*/
if ((peercert = SSL_get_peer_certificate(TLScontext->con)) != 0) {
TLScontext->peer_status |= TLS_CERT_FLAG_PRESENT;
/*
* Peer name or fingerprint verification as requested.
* Unconditionally set peer_CN, issuer_CN and peer_cert_fprint. Check
* fingerprint first, and avoid logging verified as untrusted in the
* call to verify_extract_name().
*/
verify_extract_print(TLScontext, peercert, props);
verify_extract_name(TLScontext, peercert, props);
if (TLScontext->log_mask &
(TLS_LOG_CERTMATCH | TLS_LOG_VERBOSE | TLS_LOG_PEERCERT))
msg_info("%s: subject_CN=%s, issuer_CN=%s, "
"fingerprint=%s, pkey_fingerprint=%s", props->namaddr,
TLScontext->peer_CN, TLScontext->issuer_CN,
TLScontext->peer_cert_fprint,
TLScontext->peer_pkey_fprint);
X509_free(peercert);
} else {
TLScontext->issuer_CN = mystrdup("");
TLScontext->peer_CN = mystrdup("");
TLScontext->peer_cert_fprint = mystrdup("");
TLScontext->peer_pkey_fprint = mystrdup("");
}
/*
* Finally, collect information about protocol and cipher for logging
*/
TLScontext->protocol = SSL_get_version(TLScontext->con);
cipher = SSL_get_current_cipher(TLScontext->con);
TLScontext->cipher_name = SSL_CIPHER_get_name(cipher);
TLScontext->cipher_usebits = SSL_CIPHER_get_bits(cipher,
&(TLScontext->cipher_algbits));
/*
* The TLS engine is active. Switch to the tls_timed_read/write()
* functions and make the TLScontext available to those functions.
*/
tls_stream_start(props->stream, TLScontext);
/*
* All the key facts in a single log entry.
*/
if (log_mask & TLS_LOG_SUMMARY)
msg_info("%s TLS connection established to %s: %s with cipher %s "
"(%d/%d bits)",
!TLS_CERT_IS_PRESENT(TLScontext) ? "Anonymous" :
TLS_CERT_IS_MATCHED(TLScontext) ? "Verified" :
TLS_CERT_IS_TRUSTED(TLScontext) ? "Trusted" : "Untrusted",
props->namaddr, TLScontext->protocol, TLScontext->cipher_name,
TLScontext->cipher_usebits, TLScontext->cipher_algbits);
tls_int_seed();
return (TLScontext);
}
static void verify_extract_name(TLS_SESS_STATE *TLScontext, X509 *peercert,
const TLS_CLIENT_START_PROPS *props)
{
int i;
int r;
int matched = 0;
int dnsname_match;
int verify_peername = 0;
int log_certmatch;
int verbose;
const char *dnsname;
const GENERAL_NAME *gn;
general_name_stack_t *gens;
/*
* On exit both peer_CN and issuer_CN should be set.
*/
TLScontext->issuer_CN = tls_issuer_CN(peercert, TLScontext);
/*
* Is the certificate trust chain valid and trusted?
*/
if (SSL_get_verify_result(TLScontext->con) == X509_V_OK)
TLScontext->peer_status |= TLS_CERT_FLAG_TRUSTED;
/*
* With fingerprint or dane we may already be done. Otherwise, verify the
* peername if using traditional PKI or DANE with trust-anchors.
*/
if (!TLS_CERT_IS_MATCHED(TLScontext)
&& TLS_CERT_IS_TRUSTED(TLScontext)
&& TLS_MUST_TRUST(props->tls_level))
verify_peername = 1;
/* Force cert processing so we can log the data? */
log_certmatch = TLScontext->log_mask & TLS_LOG_CERTMATCH;
/* Log cert details when processing? */
verbose = log_certmatch || (TLScontext->log_mask & TLS_LOG_VERBOSE);
if (verify_peername || log_certmatch) {
/*
* Verify the dNSName(s) in the peer certificate against the nexthop
* and hostname.
*
* If DNS names are present, we use the first matching (or else simply
* the first) DNS name as the subject CN. The CommonName in the
* issuer DN is obsolete when SubjectAltName is available. This
* yields much less surprising logs, because we log the name we
* verified or a name we checked and failed to match.
*
* XXX: The nexthop and host name may both be the same network address
* rather than a DNS name. In this case we really should be looking
* for GEN_IPADD entries, not GEN_DNS entries.
*
* XXX: In ideal world the caller who used the address to build the
* connection would tell us that the nexthop is the connection
* address, but if that is not practical, we can parse the nexthop
* again here.
*/
gens = X509_get_ext_d2i(peercert, NID_subject_alt_name, 0, 0);
if (gens) {
r = sk_GENERAL_NAME_num(gens);
for (i = 0; i < r; ++i) {
gn = sk_GENERAL_NAME_value(gens, i);
if (gn->type != GEN_DNS)
continue;
/*
* Even if we have an invalid DNS name, we still ultimately
* ignore the CommonName, because subjectAltName:DNS is
* present (though malformed). Replace any previous peer_CN
* if empty or we get a match.
*
* We always set at least an empty peer_CN if the ALTNAME cert
* flag is set. If not, we set peer_CN from the cert
* CommonName below, so peer_CN is always non-null on return.
*/
TLScontext->peer_status |= TLS_CERT_FLAG_ALTNAME;
dnsname = tls_dns_name(gn, TLScontext);
if (dnsname && *dnsname) {
if ((dnsname_match = match_servername(dnsname, props)) != 0)
matched++;
/* Keep the first matched name. */
if (TLScontext->peer_CN
&& ((dnsname_match && matched == 1)
|| *TLScontext->peer_CN == 0)) {
myfree(TLScontext->peer_CN);
TLScontext->peer_CN = 0;
}
if (verbose)
msg_info("%s: %ssubjectAltName: %s", props->namaddr,
dnsname_match ? "Matched " : "", dnsname);
}
if (TLScontext->peer_CN == 0)
TLScontext->peer_CN = mystrdup(dnsname ? dnsname : "");
if (matched && !log_certmatch)
break;
}
if (verify_peername && matched)
TLScontext->peer_status |= TLS_CERT_FLAG_MATCHED;
/*
* (Sam Rushing, Ironport) Free stack *and* member GENERAL_NAME
* objects
*/
sk_GENERAL_NAME_pop_free(gens, GENERAL_NAME_free);
}
/*
* No subjectAltNames, peer_CN is taken from CommonName.
*/
if (TLScontext->peer_CN == 0) {
TLScontext->peer_CN = tls_peer_CN(peercert, TLScontext);
if (*TLScontext->peer_CN)
matched = match_servername(TLScontext->peer_CN, props);
if (verify_peername && matched)
TLScontext->peer_status |= TLS_CERT_FLAG_MATCHED;
if (verbose)
msg_info("%s %sCommonName %s", props->namaddr,
matched ? "Matched " : "", TLScontext->peer_CN);
} else if (verbose) {
char *tmpcn = tls_peer_CN(peercert, TLScontext);
/*
* Though the CommonName was superceded by a subjectAltName, log
* it when certificate match debugging was requested.
*/
msg_info("%s CommonName %s", TLScontext->namaddr, tmpcn);
myfree(tmpcn);
}
} else
TLScontext->peer_CN = tls_peer_CN(peercert, TLScontext);
/*
* Give them a clue. Problems with trust chain verification are logged
* when the session is first negotiated, before the session is stored
* into the cache. We don't want mystery failures, so log the fact the
* real problem is to be found in the past.
*/
if (!TLS_CERT_IS_TRUSTED(TLScontext)
&& (TLScontext->log_mask & TLS_LOG_UNTRUSTED)) {
if (TLScontext->session_reused == 0)
tls_log_verify_error(TLScontext);
else
msg_info("%s: re-using session with untrusted certificate, "
"look for details earlier in the log", props->namaddr);
}
}
/*
* This is the actual startup routine for the connection. We expect that the
* buffers are flushed and the "220 Ready to start TLS" was received by us,
* so that we can immediately start the TLS handshake process.
*/
TLS_SESS_STATE *tls_client_start(const TLS_CLIENT_START_PROPS *props)
{
int sts;
int protomask;
const char *cipher_list;
SSL_SESSION *session;
const SSL_CIPHER *cipher;
X509 *peercert;
TLS_SESS_STATE *TLScontext;
TLS_APPL_STATE *app_ctx = props->ctx;
VSTRING *myserverid;
int log_mask = app_ctx->log_mask;
/*
* When certificate verification is required, log trust chain validation
* errors even when disabled by default for opportunistic sessions.
*/
if (props->tls_level >= TLS_LEV_VERIFY)
log_mask |= TLS_LOG_UNTRUSTED;
if (log_mask & TLS_LOG_VERBOSE)
msg_info("setting up TLS connection to %s", props->namaddr);
/*
* First make sure we have valid protocol and cipher parameters
*
* The cipherlist will be applied to the global SSL context, where it can be
* repeatedly reset if necessary, but the protocol restrictions will be
* is applied to the SSL connection, because protocol restrictions in the
* global context cannot be cleared.
*/
/*
* OpenSSL will ignore cached sessions that use the wrong protocol. So we
* do not need to filter out cached sessions with the "wrong" protocol,
* rather OpenSSL will simply negotiate a new session.
*
* Still, we salt the session lookup key with the protocol list, so that
* sessions found in the cache are always acceptable.
*/
protomask = tls_protocol_mask(props->protocols);
if (protomask == TLS_PROTOCOL_INVALID) {
/* tls_protocol_mask() logs no warning. */
msg_warn("%s: Invalid TLS protocol list \"%s\": aborting TLS session",
props->namaddr, props->protocols);
return (0);
}
myserverid = vstring_alloc(100);
vstring_sprintf_append(myserverid, "%s&p=%d", props->serverid, protomask);
/*
* Per session cipher selection for sessions with mandatory encryption
*
* By the time a TLS client is negotiating ciphers it has already offered to
* re-use a session, it is too late to renege on the offer. So we must
* not attempt to re-use sessions whose ciphers are too weak. We salt the
* session lookup key with the cipher list, so that sessions found in the
* cache are always acceptable.
*/
cipher_list = tls_set_ciphers(app_ctx, "TLS", props->cipher_grade,
props->cipher_exclusions);
if (cipher_list == 0) {
msg_warn("%s: %s: aborting TLS session",
props->namaddr, vstring_str(app_ctx->why));
vstring_free(myserverid);
return (0);
}
if (log_mask & TLS_LOG_VERBOSE)
msg_info("%s: TLS cipher list \"%s\"", props->namaddr, cipher_list);
vstring_sprintf_append(myserverid, "&c=%s", cipher_list);
/*
* Finally, salt the session key with the OpenSSL library version,
* (run-time, rather than compile-time, just in case that matters).
*/
vstring_sprintf_append(myserverid, "&l=%ld", (long) SSLeay());
/*
* Allocate a new TLScontext for the new connection and get an SSL
* structure. Add the location of TLScontext to the SSL to later retrieve
* the information inside the tls_verify_certificate_callback().
*
* If session caching was enabled when TLS was initialized, the cache type
* is stored in the client SSL context.
*/
TLScontext = tls_alloc_sess_context(log_mask, props->namaddr);
TLScontext->cache_type = app_ctx->cache_type;
TLScontext->serverid = vstring_export(myserverid);
TLScontext->stream = props->stream;
if ((TLScontext->con = SSL_new(app_ctx->ssl_ctx)) == NULL) {
msg_warn("Could not allocate 'TLScontext->con' with SSL_new()");
tls_print_errors();
tls_free_context(TLScontext);
return (0);
}
if (!SSL_set_ex_data(TLScontext->con, TLScontext_index, TLScontext)) {
msg_warn("Could not set application data for 'TLScontext->con'");
tls_print_errors();
tls_free_context(TLScontext);
return (0);
}
/*
* Apply session protocol restrictions.
*/
if (protomask != 0)
SSL_set_options(TLScontext->con,
((protomask & TLS_PROTOCOL_TLSv1) ? SSL_OP_NO_TLSv1 : 0L)
| ((protomask & TLS_PROTOCOL_TLSv1_1) ? SSL_OP_NO_TLSv1_1 : 0L)
| ((protomask & TLS_PROTOCOL_TLSv1_2) ? SSL_OP_NO_TLSv1_2 : 0L)
| ((protomask & TLS_PROTOCOL_SSLv3) ? SSL_OP_NO_SSLv3 : 0L)
| ((protomask & TLS_PROTOCOL_SSLv2) ? SSL_OP_NO_SSLv2 : 0L));
/*
* XXX To avoid memory leaks we must always call SSL_SESSION_free() after
* calling SSL_set_session(), regardless of whether or not the session
* will be reused.
*/
if (TLScontext->cache_type) {
session = load_clnt_session(TLScontext);
if (session) {
SSL_set_session(TLScontext->con, session);
SSL_SESSION_free(session); /* 200411 */
#if (OPENSSL_VERSION_NUMBER < 0x00906011L) || (OPENSSL_VERSION_NUMBER == 0x00907000L)
/*
* Ugly Hack: OpenSSL before 0.9.6a does not store the verify
* result in sessions for the client side. We modify the session
* directly which is version specific, but this bug is version
* specific, too.
*
* READ: 0-09-06-01-1 = 0-9-6-a-beta1: all versions before beta1
* have this bug, it has been fixed during development of 0.9.6a.
* The development version of 0.9.7 can have this bug, too. It
* has been fixed on 2000/11/29.
*/
SSL_set_verify_result(TLScontext->con, session->verify_result);
#endif
}
}
/*
* Before really starting anything, try to seed the PRNG a little bit
* more.
*/
tls_int_seed();
(void) tls_ext_seed(var_tls_daemon_rand_bytes);
/*
* Initialize the SSL connection to connect state. This should not be
* necessary anymore since 0.9.3, but the call is still in the library
* and maintaining compatibility never hurts.
*/
SSL_set_connect_state(TLScontext->con);
/*
* Connect the SSL connection with the network socket.
*/
if (SSL_set_fd(TLScontext->con, vstream_fileno(props->stream)) != 1) {
msg_info("SSL_set_fd error to %s", props->namaddr);
tls_print_errors();
uncache_session(app_ctx->ssl_ctx, TLScontext);
tls_free_context(TLScontext);
return (0);
}
/*
* Turn on non-blocking I/O so that we can enforce timeouts on network
* I/O.
*/
non_blocking(vstream_fileno(props->stream), NON_BLOCKING);
/*
* If the debug level selected is high enough, all of the data is dumped:
* TLS_LOG_TLSPKTS will dump the SSL negotiation, TLS_LOG_ALLPKTS will
* dump everything.
*
* We do have an SSL_set_fd() and now suddenly a BIO_ routine is called?
* Well there is a BIO below the SSL routines that is automatically
* created for us, so we can use it for debugging purposes.
*/
if (log_mask & TLS_LOG_TLSPKTS)
BIO_set_callback(SSL_get_rbio(TLScontext->con), tls_bio_dump_cb);
/*
* Start TLS negotiations. This process is a black box that invokes our
* call-backs for certificate verification.
*
* Error handling: If the SSL handhake fails, we print out an error message
* and remove all TLS state concerning this session.
*/
sts = tls_bio_connect(vstream_fileno(props->stream), props->timeout,
TLScontext);
if (sts <= 0) {
if (ERR_peek_error() != 0) {
msg_info("SSL_connect error to %s: %d", props->namaddr, sts);
tls_print_errors();
} else if (errno != 0) {
msg_info("SSL_connect error to %s: %m", props->namaddr);
} else {
msg_info("SSL_connect error to %s: lost connection",
props->namaddr);
}
uncache_session(app_ctx->ssl_ctx, TLScontext);
tls_free_context(TLScontext);
return (0);
}
/* Turn off packet dump if only dumping the handshake */
if ((log_mask & TLS_LOG_ALLPKTS) == 0)
BIO_set_callback(SSL_get_rbio(TLScontext->con), 0);
/*
* The caller may want to know if this session was reused or if a new
* session was negotiated.
*/
TLScontext->session_reused = SSL_session_reused(TLScontext->con);
if ((log_mask & TLS_LOG_CACHE) && TLScontext->session_reused)
msg_info("%s: Reusing old session", TLScontext->namaddr);
/*
* Do peername verification if requested and extract useful information
* from the certificate for later use.
*/
if ((peercert = SSL_get_peer_certificate(TLScontext->con)) != 0) {
TLScontext->peer_status |= TLS_CERT_FLAG_PRESENT;
/*
* Peer name or fingerprint verification as requested.
* Unconditionally set peer_CN, issuer_CN and peer_fingerprint.
*/
verify_extract_name(TLScontext, peercert, props);
verify_extract_print(TLScontext, peercert, props);
if (TLScontext->log_mask &
(TLS_LOG_CERTMATCH | TLS_LOG_VERBOSE | TLS_LOG_PEERCERT))
msg_info("%s: subject_CN=%s, issuer_CN=%s, "
"fingerprint %s, pkey_fingerprint=%s", props->namaddr,
TLScontext->peer_CN, TLScontext->issuer_CN,
TLScontext->peer_fingerprint,
TLScontext->peer_pkey_fprint);
X509_free(peercert);
} else {
TLScontext->issuer_CN = mystrdup("");
TLScontext->peer_CN = mystrdup("");
TLScontext->peer_fingerprint = mystrdup("");
TLScontext->peer_pkey_fprint = mystrdup("");
}
/*
* Finally, collect information about protocol and cipher for logging
*/
TLScontext->protocol = SSL_get_version(TLScontext->con);
cipher = SSL_get_current_cipher(TLScontext->con);
TLScontext->cipher_name = SSL_CIPHER_get_name(cipher);
TLScontext->cipher_usebits = SSL_CIPHER_get_bits(cipher,
&(TLScontext->cipher_algbits));
/*
* The TLS engine is active. Switch to the tls_timed_read/write()
* functions and make the TLScontext available to those functions.
*/
tls_stream_start(props->stream, TLScontext);
/*
* All the key facts in a single log entry.
*/
if (log_mask & TLS_LOG_SUMMARY)
msg_info("%s TLS connection established to %s: %s with cipher %s "
"(%d/%d bits)", TLS_CERT_IS_MATCHED(TLScontext) ? "Verified" :
TLS_CERT_IS_TRUSTED(TLScontext) ? "Trusted" : "Untrusted",
props->namaddr, TLScontext->protocol, TLScontext->cipher_name,
TLScontext->cipher_usebits, TLScontext->cipher_algbits);
tls_int_seed();
return (TLScontext);
}
/*
* This is the actual startup routine for the connection. We expect that the
* buffers are flushed and the "220 Ready to start TLS" was received by us,
* so that we can immediately start the TLS handshake process.
*/
TLS_SESS_STATE *tls_client_start(const TLS_CLIENT_START_PROPS *props)
{
const char *myname = "tls_client_start";
int sts;
int protomask;
const char *cipher_list;
SSL_SESSION *session;
SSL_CIPHER *cipher;
X509 *peercert;
TLS_SESS_STATE *TLScontext;
TLS_APPL_STATE *app_ctx = props->ctx;
ACL_VSTRING *myserverid;
if (props->log_level >= 1)
acl_msg_info("%s(%d): setting up TLS connection to %s",
myname, __LINE__, props->namaddr);
/*
* First make sure we have valid protocol and cipher parameters
*
* The cipherlist will be applied to the global SSL context, where it can be
* repeatedly reset if necessary, but the protocol restrictions will be
* is applied to the SSL connection, because protocol restrictions in the
* global context cannot be cleared.
*/
/*
* OpenSSL will ignore cached sessions that use the wrong protocol. So we
* do not need to filter out cached sessions with the "wrong" protocol,
* rather OpenSSL will simply negotiate a new session.
*
* Still, we salt the session lookup key with the protocol list, so that
* sessions found in the cache are always acceptable.
*/
protomask = tls_protocol_mask(props->protocols);
if (protomask == TLS_PROTOCOL_INVALID) {
/* tls_protocol_mask() logs no warning. */
acl_msg_warn("%s(%d): nameaddr: %s: Invalid TLS protocol list \"%s\": aborting TLS session",
myname, __LINE__, props->namaddr, props->protocols);
return (0);
}
myserverid = acl_vstring_alloc(100);
acl_vstring_sprintf_append(myserverid, "%s&p=%d", props->serverid, protomask);
/*
* Per session cipher selection for sessions with mandatory encryption
*
* By the time a TLS client is negotiating ciphers it has already offered to
* re-use a session, it is too late to renege on the offer. So we must
* not attempt to re-use sessions whose ciphers are too weak. We salt the
* session lookup key with the cipher list, so that sessions found in the
* cache are always acceptable.
*/
cipher_list = tls_set_ciphers(app_ctx, "TLS", props->cipher_grade,
props->cipher_exclusions);
if (cipher_list == 0) {
acl_msg_warn("%s(%d): %s: %s: aborting TLS session",
myname, __LINE__, props->namaddr, acl_vstring_str(app_ctx->why));
acl_vstring_free(myserverid);
return (0);
}
if (props->log_level >= 2)
acl_msg_info("%s(%d): %s: TLS cipher list \"%s\"",
myname, __LINE__, props->namaddr, cipher_list);
acl_vstring_sprintf_append(myserverid, "&c=%s", cipher_list);
/*
* Allocate a new TLScontext for the new connection and get an SSL
* structure. Add the location of TLScontext to the SSL to later retrieve
* the information inside the tls_verify_certificate_callback().
*
* If session caching was enabled when TLS was initialized, the cache type
* is stored in the client SSL context.
*/
TLScontext = tls_alloc_sess_context(props->log_level, props->namaddr);
TLScontext->cache_type = app_ctx->cache_type;
TLScontext->serverid = acl_vstring_export(myserverid);
if ((TLScontext->con = SSL_new(app_ctx->ssl_ctx)) == NULL) {
acl_msg_warn("%s(%d): Could not allocate 'TLScontext->con' with SSL_new()",
myname, __LINE__);
tls_print_errors();
tls_free_context(TLScontext);
return (0);
}
if (!SSL_set_ex_data(TLScontext->con, TLScontext_index, TLScontext)) {
acl_msg_warn("%s(%d): Could not set application data for 'TLScontext->con'",
myname, __LINE__);
tls_print_errors();
tls_free_context(TLScontext);
return (0);
}
/*
* Apply session protocol restrictions.
*/
if (protomask != 0)
SSL_set_options(TLScontext->con,
((protomask & TLS_PROTOCOL_TLSv1) ? SSL_OP_NO_TLSv1 : 0L)
| ((protomask & TLS_PROTOCOL_SSLv3) ? SSL_OP_NO_SSLv3 : 0L)
| ((protomask & TLS_PROTOCOL_SSLv2) ? SSL_OP_NO_SSLv2 : 0L));
/*
* The TLS connection is realized by a BIO_pair, so obtain the pair.
*
* XXX There is no need to make internal_bio a member of the TLScontext
* structure. It will be attached to TLScontext->con, and destroyed along
* with it. The network_bio, however, needs to be freed explicitly.
*/
if (!BIO_new_bio_pair(&TLScontext->internal_bio, TLS_BIO_BUFSIZE,
&TLScontext->network_bio, TLS_BIO_BUFSIZE)) {
acl_msg_warn("%s(%d): Could not obtain BIO_pair", myname, __LINE__);
tls_print_errors();
tls_free_context(TLScontext);
return (0);
}
/*
* XXX To avoid memory leaks we must always call SSL_SESSION_free() after
* calling SSL_set_session(), regardless of whether or not the session
* will be reused.
*/
if (TLScontext->cache_type) {
session = load_clnt_session(TLScontext);
if (session) {
SSL_set_session(TLScontext->con, session);
SSL_SESSION_free(session); /* 200411 */
#if (OPENSSL_VERSION_NUMBER < 0x00906011L) || (OPENSSL_VERSION_NUMBER == 0x00907000L)
/*
* Ugly Hack: OpenSSL before 0.9.6a does not store the verify
* result in sessions for the client side. We modify the session
* directly which is version specific, but this bug is version
* specific, too.
*
* READ: 0-09-06-01-1 = 0-9-6-a-beta1: all versions before beta1
* have this bug, it has been fixed during development of 0.9.6a.
* The development version of 0.9.7 can have this bug, too. It
* has been fixed on 2000/11/29.
*/
SSL_set_verify_result(TLScontext->con, session->verify_result);
#endif
}
}
/*
* Before really starting anything, try to seed the PRNG a little bit
* more.
*/
tls_int_seed();
if (var_tls_daemon_rand_bytes > 0)
(void) tls_ext_seed(var_tls_daemon_rand_bytes);
/*
* Initialize the SSL connection to connect state. This should not be
* necessary anymore since 0.9.3, but the call is still in the library
* and maintaining compatibility never hurts.
*/
SSL_set_connect_state(TLScontext->con);
/*
* Connect the SSL connection with the Postfix side of the BIO-pair for
* reading and writing.
*/
SSL_set_bio(TLScontext->con, TLScontext->internal_bio, TLScontext->internal_bio);
/*
* If the debug level selected is high enough, all of the data is dumped:
* 3 will dump the SSL negotiation, 4 will dump everything.
*
* We do have an SSL_set_fd() and now suddenly a BIO_ routine is called?
* Well there is a BIO below the SSL routines that is automatically
* created for us, so we can use it for debugging purposes.
*/
if (props->log_level >= 3)
BIO_set_callback(SSL_get_rbio(TLScontext->con), tls_bio_dump_cb);
/*
* Start TLS negotiations. This process is a black box that invokes our
* call-backs for certificate verification.
*
* Error handling: If the SSL handhake fails, we print out an error message
* and remove all TLS state concerning this session.
*/
sts = tls_bio_connect(ACL_VSTREAM_SOCK(props->stream), props->timeout,
TLScontext);
if (sts <= 0) {
acl_msg_info("%s(%d): SSL_connect error to %s: %d",
myname, __LINE__, props->namaddr, sts);
tls_print_errors();
uncache_session(app_ctx->ssl_ctx, TLScontext);
tls_free_context(TLScontext);
return (0);
}
/* Only log_level==4 dumps everything */
if (props->log_level < 4)
BIO_set_callback(SSL_get_rbio(TLScontext->con), 0);
/*
* The caller may want to know if this session was reused or if a new
* session was negotiated.
*/
TLScontext->session_reused = SSL_session_reused(TLScontext->con);
if (props->log_level >= 2 && TLScontext->session_reused)
acl_msg_info("%s(%d): %s: Reusing old session",
myname, __LINE__, TLScontext->namaddr);
/*
* Do peername verification if requested and extract useful information
* from the certificate for later use.
*/
if ((peercert = SSL_get_peer_certificate(TLScontext->con)) != 0) {
TLScontext->peer_status |= TLS_CERT_FLAG_PRESENT;
/*
* Peer name or fingerprint verification as requested.
* Unconditionally set peer_CN, issuer_CN and peer_fingerprint.
*/
verify_extract_name(TLScontext, peercert, props);
verify_extract_print(TLScontext, peercert, props);
X509_free(peercert);
} else {
TLScontext->issuer_CN = acl_mystrdup("");
TLScontext->peer_CN = acl_mystrdup("");
TLScontext->peer_fingerprint = acl_mystrdup("");
}
/*
* Finally, collect information about protocol and cipher for logging
*/
TLScontext->protocol = SSL_get_version(TLScontext->con);
cipher = SSL_get_current_cipher(TLScontext->con);
TLScontext->cipher_name = SSL_CIPHER_get_name(cipher);
TLScontext->cipher_usebits = SSL_CIPHER_get_bits(cipher,
&(TLScontext->cipher_algbits));
/*
* The TLS engine is active. Switch to the tls_timed_read/write()
* functions and make the TLScontext available to those functions.
*/
tls_stream_start(props->stream, TLScontext);
/*
* All the key facts in a single log entry.
*/
if (props->log_level >= 1)
acl_msg_info("%s(%d): %s TLS connection established to %s: %s with cipher %s "
"(%d/%d bits)", myname, __LINE__,
TLS_CERT_IS_MATCHED(TLScontext) ? "Verified" :
TLS_CERT_IS_TRUSTED(TLScontext) ? "Trusted" : "Untrusted",
props->namaddr, TLScontext->protocol, TLScontext->cipher_name,
TLScontext->cipher_usebits, TLScontext->cipher_algbits);
tls_int_seed();
return (TLScontext);
}
static void verify_extract_name(TLS_SESS_STATE *TLScontext, X509 *peercert,
const TLS_CLIENT_START_PROPS *props)
{
int i;
int r;
int matched = 0;
const char *dnsname;
const GENERAL_NAME *gn;
STACK_OF(GENERAL_NAME) * gens;
/*
* On exit both peer_CN and issuer_CN should be set.
*/
TLScontext->issuer_CN = tls_issuer_CN(peercert, TLScontext);
/*
* Is the certificate trust chain valid and trusted?
*/
if (SSL_get_verify_result(TLScontext->con) == X509_V_OK)
TLScontext->peer_status |= TLS_CERT_FLAG_TRUSTED;
if (TLS_CERT_IS_TRUSTED(TLScontext) && props->tls_level >= TLS_LEV_VERIFY) {
/*
* Verify the dNSName(s) in the peer certificate against the nexthop
* and hostname.
*
* If DNS names are present, we use the first matching (or else simply
* the first) DNS name as the subject CN. The CommonName in the
* issuer DN is obsolete when SubjectAltName is available. This
* yields much less surprising logs, because we log the name we
* verified or a name we checked and failed to match.
*
* XXX: The nexthop and host name may both be the same network address
* rather than a DNS name. In this case we really should be looking
* for GEN_IPADD entries, not GEN_DNS entries.
*
* XXX: In ideal world the caller who used the address to build the
* connection would tell us that the nexthop is the connection
* address, but if that is not practical, we can parse the nexthop
* again here.
*/
gens = X509_get_ext_d2i(peercert, NID_subject_alt_name, 0, 0);
if (gens) {
r = sk_GENERAL_NAME_num(gens);
for (i = 0; i < r && !matched; ++i) {
gn = sk_GENERAL_NAME_value(gens, i);
if (gn->type != GEN_DNS)
continue;
/*
* Even if we have an invalid DNS name, we still ultimately
* ignore the CommonName, because subjectAltName:DNS is
* present (though malformed). Replace any previous peer_CN
* if empty or we get a match.
*
* We always set at least an empty peer_CN if the ALTNAME cert
* flag is set. If not, we set peer_CN from the cert
* CommonName below, so peer_CN is always non-null on return.
*/
TLScontext->peer_status |= TLS_CERT_FLAG_ALTNAME;
dnsname = tls_dns_name(gn, TLScontext);
if (dnsname && *dnsname) {
matched = match_hostname(dnsname, props);
if (TLScontext->peer_CN
&& (matched || *TLScontext->peer_CN == 0)) {
acl_myfree(TLScontext->peer_CN);
TLScontext->peer_CN = 0;
}
}
if (TLScontext->peer_CN == 0)
TLScontext->peer_CN = acl_mystrdup(dnsname ? dnsname : "");
}
/*
* (Sam Rushing, Ironport) Free stack *and* member GENERAL_NAME
* objects
*/
sk_GENERAL_NAME_pop_free(gens, GENERAL_NAME_free);
}
/*
* No subjectAltNames, peer_CN is taken from CommonName.
*/
if (TLScontext->peer_CN == 0) {
TLScontext->peer_CN = tls_peer_CN(peercert, TLScontext);
if (*TLScontext->peer_CN)
matched = match_hostname(TLScontext->peer_CN, props);
}
if (matched)
TLScontext->peer_status |= TLS_CERT_FLAG_MATCHED;
/*
* - Matched: Trusted and peername matches - Trusted: Signed by
* trusted CA(s), but peername not matched - Untrusted: Can't verify
* the trust chain, reason already logged.
*/
if (TLScontext->log_level >= 2)
acl_msg_info("%s: %s subject_CN=%s, issuer_CN=%s", props->namaddr,
TLS_CERT_IS_MATCHED(TLScontext) ? "Matched" :
TLS_CERT_IS_TRUSTED(TLScontext) ? "Trusted" : "Untrusted",
TLScontext->peer_CN, TLScontext->issuer_CN);
} else
TLScontext->peer_CN = tls_peer_CN(peercert, TLScontext);
/*
* Give them a clue. Problems with trust chain verification were logged
* when the session was first negotiated, before the session was stored
* into the cache. We don't want mystery failures, so log the fact the
* real problem is to be found in the past.
*/
if (TLScontext->session_reused
&& !TLS_CERT_IS_TRUSTED(TLScontext)
&& TLScontext->log_level >= 1)
acl_msg_info("%s: re-using session with untrusted certificate, "
"look for details earlier in the log", props->namaddr);
}
static void run_one(TLS_APPL_STATE *client_tls_ctx)
{
ACL_VSTREAM *client;
TLS_SESS_STATE *client_sess_ctx;
TLS_CLIENT_START_PROPS tls_props;
char buf[4096];
int i, ret;
time_t last, now;
int tls_level = 2;
char *tls_nexthop = "test.com.cn";
char *host = "test.com.cn";
char *namaddrport = "test.com.cn";
char *serverid = "service:addr:port:helo";
char *tls_protocols = SSL_TXT_TLSV1;
char *tls_grade = "low"; /* high, medium, low, export, null */
char *tls_exclusions = "";
ACL_ARGV *tls_matchargv = 0;
client = acl_vstream_connect(serv_addr, ACL_BLOCKING, 20, 30, 8192);
if (client == NULL) {
printf("connect %s error(%s)\n", serv_addr, acl_last_serror());
return;
}
acl_tcp_set_nodelay(ACL_VSTREAM_SOCK(client));
#if 0
client_sess_ctx = TLS_CLIENT_START(&tls_props,
ctx = client_tls_ctx,
stream = client,
log_level = var_client_tls_loglevel,
timeout = var_client_starttls_tmout,
tls_level = tls_level,
nexthop = tls_nexthop,
host = host,
namaddr = namaddrport,
serverid = serverid,
protocols = tls_protocols,
cipher_grade = tls_grade,
cipher_exclusions = tls_exclusions,
matchargv = tls_matchargv,
fpt_dgst = var_client_tls_fpt_dgst);
#else
tls_props.ctx = client_tls_ctx;
tls_props.stream = client;
tls_props.log_level = var_client_tls_loglevel;
tls_props.timeout = var_client_starttls_tmout;
tls_props.tls_level = tls_level;
tls_props.nexthop = tls_nexthop;
tls_props.host = host;
tls_props.namaddr = namaddrport;
tls_props.serverid = serverid;
tls_props.protocols = tls_protocols;
tls_props.cipher_grade = tls_grade;
tls_props.cipher_exclusions = tls_exclusions;
tls_props.matchargv = tls_matchargv;
tls_props.fpt_dgst = var_client_tls_fpt_dgst;
client_sess_ctx = tls_client_start(&tls_props);
#endif
if (client_sess_ctx == NULL) {
printf("TLS_CLIENT_START error\n");
acl_vstream_close(client);
return;
}
if (tls_level >= TLS_LEV_VERIFY) {
if (!TLS_CERT_IS_TRUSTED(client_sess_ctx)) {
printf("Server certificate not trusted\n");
}
}
if (tls_level > TLS_LEV_ENCRYPT) {
if (!TLS_CERT_IS_MATCHED(client_sess_ctx)) {
printf("Server certificate not verified\n");
}
}
time(&last);
i = 0;
while (1) {
ret = acl_vstream_fprintf(client, "hello world\n");
if (ret == ACL_VSTREAM_EOF)
goto END;
ret = acl_vstream_gets(client, buf, sizeof(buf));
if (ret == ACL_VSTREAM_EOF)
goto END;
break;
i++;
if (i % 50000 == 0) {
time(&now);
printf("client: i=%d, time=%ld\n", i, now - last);
last = now;
}
}
if (0)
{
if (acl_vstream_writen(client, request, strlen(request)) == ACL_VSTREAM_EOF)
printf("write request error\n");
else {
while (1) {
if (acl_vstream_gets_nonl(client, buf, sizeof(buf)) == ACL_VSTREAM_EOF)
break;
/*
printf("%s\n", buf);
*/
}
/*
printf("gets respond over now\n");
*/
}
}
END:
tls_client_stop(client_tls_ctx, client, var_client_starttls_tmout, 0, client_sess_ctx);
acl_vstream_close(client);
}