* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2009 */
+/* Copyright (c) University of Cambridge 1995 - 2017 */
/* See the file NOTICE for conditions of use and distribution. */
+/* Portions Copyright (c) The OpenSSL Project 1999 */
+
/* This module provides the TLS (aka SSL) support for Exim using the OpenSSL
library. It is #included into the tls.c file when that library is used. The
code herein is based on a patch that was originally contributed by Steve
#include <openssl/ssl.h>
#include <openssl/err.h>
#include <openssl/rand.h>
+#ifndef OPENSSL_NO_ECDH
+# include <openssl/ec.h>
+#endif
+#ifndef DISABLE_OCSP
+# include <openssl/ocsp.h>
+#endif
+#ifdef EXPERIMENTAL_DANE
+# include <danessl.h>
+#endif
+
+
+#ifndef DISABLE_OCSP
+# define EXIM_OCSP_SKEW_SECONDS (300L)
+# define EXIM_OCSP_MAX_AGE (-1L)
+#endif
+
+#if OPENSSL_VERSION_NUMBER >= 0x0090806fL && !defined(OPENSSL_NO_TLSEXT)
+# define EXIM_HAVE_OPENSSL_TLSEXT
+#endif
+#if OPENSSL_VERSION_NUMBER >= 0x00908000L
+# define EXIM_HAVE_RSA_GENKEY_EX
+#endif
+#if OPENSSL_VERSION_NUMBER >= 0x10100000L
+# define EXIM_HAVE_OCSP_RESP_COUNT
+#else
+# define EXIM_HAVE_EPHEM_RSA_KEX
+# define EXIM_HAVE_RAND_PSEUDO
+#endif
+#if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256)
+# define EXIM_HAVE_SHA256
+#endif
+
+/*
+ * X509_check_host provides sane certificate hostname checking, but was added
+ * to OpenSSL late, after other projects forked off the code-base. So in
+ * addition to guarding against the base version number, beware that LibreSSL
+ * does not (at this time) support this function.
+ *
+ * If LibreSSL gains a different API, perhaps via libtls, then we'll probably
+ * opt to disentangle and ask a LibreSSL user to provide glue for a third
+ * crypto provider for libtls instead of continuing to tie the OpenSSL glue
+ * into even twistier knots. If LibreSSL gains the same API, we can just
+ * change this guard and punt the issue for a while longer.
+ */
+#ifndef LIBRESSL_VERSION_NUMBER
+# if OPENSSL_VERSION_NUMBER >= 0x010100000L
+# define EXIM_HAVE_OPENSSL_CHECKHOST
+# define EXIM_HAVE_OPENSSL_DH_BITS
+# endif
+# if OPENSSL_VERSION_NUMBER >= 0x010000000L \
+ && (OPENSSL_VERSION_NUMBER & 0x0000ff000L) >= 0x000002000L
+# define EXIM_HAVE_OPENSSL_CHECKHOST
+# endif
+#endif
+
+#if !defined(LIBRESSL_VERSION_NUMBER) \
+ || LIBRESSL_VERSION_NUMBER >= 0x20010000L
+# if !defined(OPENSSL_NO_ECDH)
+# if OPENSSL_VERSION_NUMBER >= 0x0090800fL
+# define EXIM_HAVE_ECDH
+# endif
+# if OPENSSL_VERSION_NUMBER >= 0x10002000L
+# define EXIM_HAVE_OPENSSL_EC_NIST2NID
+# endif
+# endif
+#endif
+
+#if !defined(EXIM_HAVE_OPENSSL_TLSEXT) && !defined(DISABLE_OCSP)
+# warning "OpenSSL library version too old; define DISABLE_OCSP in Makefile"
+# define DISABLE_OCSP
+#endif
/* Structure for collecting random data for seeding. */
/* Local static variables */
-static BOOL verify_callback_called = FALSE;
+static BOOL client_verify_callback_called = FALSE;
+static BOOL server_verify_callback_called = FALSE;
static const uschar *sid_ctx = US"exim";
-static SSL_CTX *ctx = NULL;
-static SSL_CTX *ctx_sni = NULL;
-static SSL *ssl = NULL;
+/* We have three different contexts to care about.
+
+Simple case: client, `client_ctx`
+ As a client, we can be doing a callout or cut-through delivery while receiving
+ a message. So we have a client context, which should have options initialised
+ from the SMTP Transport.
+
+Server:
+ There are two cases: with and without ServerNameIndication from the client.
+ Given TLS SNI, we can be using different keys, certs and various other
+ configuration settings, because they're re-expanded with $tls_sni set. This
+ allows vhosting with TLS. This SNI is sent in the handshake.
+ A client might not send SNI, so we need a fallback, and an initial setup too.
+ So as a server, we start out using `server_ctx`.
+ If SNI is sent by the client, then we as server, mid-negotiation, try to clone
+ `server_sni` from `server_ctx` and then initialise settings by re-expanding
+ configuration.
+*/
+
+static SSL_CTX *client_ctx = NULL;
+static SSL_CTX *server_ctx = NULL;
+static SSL *client_ssl = NULL;
+static SSL *server_ssl = NULL;
+
+#ifdef EXIM_HAVE_OPENSSL_TLSEXT
+static SSL_CTX *server_sni = NULL;
+#endif
static char ssl_errstring[256];
static int ssl_session_timeout = 200;
-static BOOL verify_optional = FALSE;
+static BOOL client_verify_optional = FALSE;
+static BOOL server_verify_optional = FALSE;
-static BOOL reexpand_tls_files_for_sni = FALSE;
+static BOOL reexpand_tls_files_for_sni = FALSE;
typedef struct tls_ext_ctx_cb {
uschar *certificate;
uschar *privatekey;
+#ifndef DISABLE_OCSP
+ BOOL is_server;
+ STACK_OF(X509) *verify_stack; /* chain for verifying the proof */
+ union {
+ struct {
+ uschar *file;
+ uschar *file_expanded;
+ OCSP_RESPONSE *response;
+ } server;
+ struct {
+ X509_STORE *verify_store; /* non-null if status requested */
+ BOOL verify_required;
+ } client;
+ } u_ocsp;
+#endif
uschar *dhparam;
/* these are cached from first expand */
uschar *server_cipher_list;
/* only passed down to tls_error: */
host_item *host;
+ const uschar * verify_cert_hostnames;
+#ifndef DISABLE_EVENT
+ uschar * event_action;
+#endif
} tls_ext_ctx_cb;
/* should figure out a cleanup of API to handle state preserved per
implementation, for various reasons, which can be void * in the APIs.
For now, we hack around it. */
-tls_ext_ctx_cb *static_cbinfo = NULL;
+tls_ext_ctx_cb *client_static_cbinfo = NULL;
+tls_ext_ctx_cb *server_static_cbinfo = NULL;
static int
-setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional);
+setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional,
+ int (*cert_vfy_cb)(int, X509_STORE_CTX *), uschar ** errstr );
+
+/* Callbacks */
+#ifdef EXIM_HAVE_OPENSSL_TLSEXT
+static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg);
+#endif
+#ifndef DISABLE_OCSP
+static int tls_server_stapling_cb(SSL *s, void *arg);
+#endif
/*************************************************
host NULL if setting up a server;
the connected host if setting up a client
msg error message or NULL if we should ask OpenSSL
+ errstr pointer to output error message
Returns: OK/DEFER/FAIL
*/
static int
-tls_error(uschar *prefix, host_item *host, uschar *msg)
+tls_error(uschar * prefix, const host_item * host, uschar * msg, uschar ** errstr)
{
-if (msg == NULL)
+if (!msg)
{
ERR_error_string(ERR_get_error(), ssl_errstring);
- msg = (uschar *)ssl_errstring;
+ msg = US ssl_errstring;
}
-if (host == NULL)
- {
- uschar *conn_info = smtp_get_connection_info();
- if (Ustrncmp(conn_info, US"SMTP ", 5) == 0)
- conn_info += 5;
- log_write(0, LOG_MAIN, "TLS error on %s (%s): %s",
- conn_info, prefix, msg);
- return DEFER;
- }
-else
- {
- log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s): %s",
- host->name, host->address, prefix, msg);
- return FAIL;
- }
+if (errstr) *errstr = string_sprintf("(%s): %s", prefix, msg);
+return host ? FAIL : DEFER;
}
+#ifdef EXIM_HAVE_EPHEM_RSA_KEX
/*************************************************
* Callback to generate RSA key *
*************************************************/
rsa_callback(SSL *s, int export, int keylength)
{
RSA *rsa_key;
+#ifdef EXIM_HAVE_RSA_GENKEY_EX
+BIGNUM *bn = BN_new();
+#endif
+
export = export; /* Shut picky compilers up */
DEBUG(D_tls) debug_printf("Generating %d bit RSA key...\n", keylength);
-rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL);
-if (rsa_key == NULL)
+
+#ifdef EXIM_HAVE_RSA_GENKEY_EX
+if ( !BN_set_word(bn, (unsigned long)RSA_F4)
+ || !(rsa_key = RSA_new())
+ || !RSA_generate_key_ex(rsa_key, keylength, bn, NULL)
+ )
+#else
+if (!(rsa_key = RSA_generate_key(keylength, RSA_F4, NULL, NULL)))
+#endif
+
{
ERR_error_string(ERR_get_error(), ssl_errstring);
log_write(0, LOG_MAIN|LOG_PANIC, "TLS error (RSA_generate_key): %s",
}
return rsa_key;
}
+#endif
+
+
+
+/* Extreme debug
+#ifndef DISABLE_OCSP
+void
+x509_store_dump_cert_s_names(X509_STORE * store)
+{
+STACK_OF(X509_OBJECT) * roots= store->objs;
+int i;
+static uschar name[256];
+
+for(i= 0; i<sk_X509_OBJECT_num(roots); i++)
+ {
+ X509_OBJECT * tmp_obj= sk_X509_OBJECT_value(roots, i);
+ if(tmp_obj->type == X509_LU_X509)
+ {
+ X509 * current_cert= tmp_obj->data.x509;
+ X509_NAME_oneline(X509_get_subject_name(current_cert), CS name, sizeof(name));
+ name[sizeof(name)-1] = '\0';
+ debug_printf(" %s\n", name);
+ }
+ }
+}
+#endif
+*/
+#ifndef DISABLE_EVENT
+static int
+verify_event(tls_support * tlsp, X509 * cert, int depth, const uschar * dn,
+ BOOL *calledp, const BOOL *optionalp, const uschar * what)
+{
+uschar * ev;
+uschar * yield;
+X509 * old_cert;
+ev = tlsp == &tls_out ? client_static_cbinfo->event_action : event_action;
+if (ev)
+ {
+ DEBUG(D_tls) debug_printf("verify_event: %s %d\n", what, depth);
+ old_cert = tlsp->peercert;
+ tlsp->peercert = X509_dup(cert);
+ /* NB we do not bother setting peerdn */
+ if ((yield = event_raise(ev, US"tls:cert", string_sprintf("%d", depth))))
+ {
+ log_write(0, LOG_MAIN, "[%s] %s verify denied by event-action: "
+ "depth=%d cert=%s: %s",
+ tlsp == &tls_out ? deliver_host_address : sender_host_address,
+ what, depth, dn, yield);
+ *calledp = TRUE;
+ if (!*optionalp)
+ {
+ if (old_cert) tlsp->peercert = old_cert; /* restore 1st failing cert */
+ return 1; /* reject (leaving peercert set) */
+ }
+ DEBUG(D_tls) debug_printf("Event-action verify failure overridden "
+ "(host in tls_try_verify_hosts)\n");
+ }
+ X509_free(tlsp->peercert);
+ tlsp->peercert = old_cert;
+ }
+return 0;
+}
+#endif
/*************************************************
* Callback for verification *
/* The SSL library does certificate verification if set up to do so. This
callback has the current yes/no state is in "state". If verification succeeded,
-we set up the tls_peerdn string. If verification failed, what happens depends
-on whether the client is required to present a verifiable certificate or not.
+we set the certificate-verified flag. If verification failed, what happens
+depends on whether the client is required to present a verifiable certificate
+or not.
If verification is optional, we change the state to yes, but still log the
verification error. For some reason (it really would help to have proper
documentation of OpenSSL), this callback function then gets called again, this
-time with state = 1. In fact, that's useful, because we can set up the peerdn
-value, but we must take care not to set the private verified flag on the second
-time through.
+time with state = 1. We must take care not to set the private verified flag on
+the second time through.
Note: this function is not called if the client fails to present a certificate
when asked. We get here only if a certificate has been received. Handling of
optional verification for this case is done when requesting SSL to verify, by
setting SSL_VERIFY_FAIL_IF_NO_PEER_CERT in the non-optional case.
+May be called multiple times for different issues with a certificate, even
+for a given "depth" in the certificate chain.
+
Arguments:
- state current yes/no state as 1/0
- x509ctx certificate information.
+ preverify_ok current yes/no state as 1/0
+ x509ctx certificate information.
+ tlsp per-direction (client vs. server) support data
+ calledp has-been-called flag
+ optionalp verification-is-optional flag
-Returns: 1 if verified, 0 if not
+Returns: 0 if verification should fail, otherwise 1
*/
static int
-verify_callback(int state, X509_STORE_CTX *x509ctx)
+verify_callback(int preverify_ok, X509_STORE_CTX *x509ctx,
+ tls_support *tlsp, BOOL *calledp, BOOL *optionalp)
{
-static uschar txt[256];
+X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx);
+int depth = X509_STORE_CTX_get_error_depth(x509ctx);
+uschar dn[256];
-X509_NAME_oneline(X509_get_subject_name(x509ctx->current_cert),
- CS txt, sizeof(txt));
+X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn));
+dn[sizeof(dn)-1] = '\0';
-if (state == 0)
+if (preverify_ok == 0)
{
- log_write(0, LOG_MAIN, "SSL verify error: depth=%d error=%s cert=%s",
- x509ctx->error_depth,
- X509_verify_cert_error_string(x509ctx->error),
- txt);
- tls_certificate_verified = FALSE;
- verify_callback_called = TRUE;
- if (!verify_optional) return 0; /* reject */
+ uschar * extra = verify_mode ? string_sprintf(" (during %c-verify for [%s])",
+ *verify_mode, sender_host_address)
+ : US"";
+ log_write(0, LOG_MAIN, "[%s] SSL verify error%s: depth=%d error=%s cert=%s",
+ tlsp == &tls_out ? deliver_host_address : sender_host_address,
+ extra, depth,
+ X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509ctx)), dn);
+ *calledp = TRUE;
+ if (!*optionalp)
+ {
+ if (!tlsp->peercert)
+ tlsp->peercert = X509_dup(cert); /* record failing cert */
+ return 0; /* reject */
+ }
DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in "
"tls_try_verify_hosts)\n");
- return 1; /* accept */
}
-if (x509ctx->error_depth != 0)
+else if (depth != 0)
{
- DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d cert=%s\n",
- x509ctx->error_depth, txt);
+ DEBUG(D_tls) debug_printf("SSL verify ok: depth=%d SN=%s\n", depth, dn);
+#ifndef DISABLE_OCSP
+ if (tlsp == &tls_out && client_static_cbinfo->u_ocsp.client.verify_store)
+ { /* client, wanting stapling */
+ /* Add the server cert's signing chain as the one
+ for the verification of the OCSP stapled information. */
+
+ if (!X509_STORE_add_cert(client_static_cbinfo->u_ocsp.client.verify_store,
+ cert))
+ ERR_clear_error();
+ sk_X509_push(client_static_cbinfo->verify_stack, cert);
+ }
+#endif
+#ifndef DISABLE_EVENT
+ if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL"))
+ return 0; /* reject, with peercert set */
+#endif
}
else
{
- DEBUG(D_tls) debug_printf("SSL%s peer: %s\n",
- verify_callback_called? "" : " authenticated", txt);
- tls_peerdn = txt;
+ const uschar * verify_cert_hostnames;
+
+ if ( tlsp == &tls_out
+ && ((verify_cert_hostnames = client_static_cbinfo->verify_cert_hostnames)))
+ /* client, wanting hostname check */
+ {
+
+#ifdef EXIM_HAVE_OPENSSL_CHECKHOST
+# ifndef X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS
+# define X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS 0
+# endif
+# ifndef X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS
+# define X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS 0
+# endif
+ int sep = 0;
+ const uschar * list = verify_cert_hostnames;
+ uschar * name;
+ int rc;
+ while ((name = string_nextinlist(&list, &sep, NULL, 0)))
+ if ((rc = X509_check_host(cert, CCS name, 0,
+ X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS
+ | X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS,
+ NULL)))
+ {
+ if (rc < 0)
+ {
+ log_write(0, LOG_MAIN, "[%s] SSL verify error: internal error",
+ tlsp == &tls_out ? deliver_host_address : sender_host_address);
+ name = NULL;
+ }
+ break;
+ }
+ if (!name)
+#else
+ if (!tls_is_name_for_cert(verify_cert_hostnames, cert))
+#endif
+ {
+ uschar * extra = verify_mode
+ ? string_sprintf(" (during %c-verify for [%s])",
+ *verify_mode, sender_host_address)
+ : US"";
+ log_write(0, LOG_MAIN,
+ "[%s] SSL verify error%s: certificate name mismatch: DN=\"%s\" H=\"%s\"",
+ tlsp == &tls_out ? deliver_host_address : sender_host_address,
+ extra, dn, verify_cert_hostnames);
+ *calledp = TRUE;
+ if (!*optionalp)
+ {
+ if (!tlsp->peercert)
+ tlsp->peercert = X509_dup(cert); /* record failing cert */
+ return 0; /* reject */
+ }
+ DEBUG(D_tls) debug_printf("SSL verify failure overridden (host in "
+ "tls_try_verify_hosts)\n");
+ }
+ }
+
+#ifndef DISABLE_EVENT
+ if (verify_event(tlsp, cert, depth, dn, calledp, optionalp, US"SSL"))
+ return 0; /* reject, with peercert set */
+#endif
+
+ DEBUG(D_tls) debug_printf("SSL%s verify ok: depth=0 SN=%s\n",
+ *calledp ? "" : " authenticated", dn);
+ if (!*calledp) tlsp->certificate_verified = TRUE;
+ *calledp = TRUE;
}
-if (!verify_callback_called) tls_certificate_verified = TRUE;
-verify_callback_called = TRUE;
+return 1; /* accept, at least for this level */
+}
-return 1; /* accept */
+static int
+verify_callback_client(int preverify_ok, X509_STORE_CTX *x509ctx)
+{
+return verify_callback(preverify_ok, x509ctx, &tls_out,
+ &client_verify_callback_called, &client_verify_optional);
+}
+
+static int
+verify_callback_server(int preverify_ok, X509_STORE_CTX *x509ctx)
+{
+return verify_callback(preverify_ok, x509ctx, &tls_in,
+ &server_verify_callback_called, &server_verify_optional);
}
+#ifdef EXPERIMENTAL_DANE
+
+/* This gets called *by* the dane library verify callback, which interposes
+itself.
+*/
+static int
+verify_callback_client_dane(int preverify_ok, X509_STORE_CTX * x509ctx)
+{
+X509 * cert = X509_STORE_CTX_get_current_cert(x509ctx);
+uschar dn[256];
+int depth = X509_STORE_CTX_get_error_depth(x509ctx);
+#ifndef DISABLE_EVENT
+BOOL dummy_called, optional = FALSE;
+#endif
+
+X509_NAME_oneline(X509_get_subject_name(cert), CS dn, sizeof(dn));
+dn[sizeof(dn)-1] = '\0';
+
+DEBUG(D_tls) debug_printf("verify_callback_client_dane: %s depth %d %s\n",
+ preverify_ok ? "ok":"BAD", depth, dn);
+
+#ifndef DISABLE_EVENT
+ if (verify_event(&tls_out, cert, depth, dn,
+ &dummy_called, &optional, US"DANE"))
+ return 0; /* reject, with peercert set */
+#endif
+
+if (preverify_ok == 1)
+ tls_out.dane_verified =
+ tls_out.certificate_verified = TRUE;
+else
+ {
+ int err = X509_STORE_CTX_get_error(x509ctx);
+ DEBUG(D_tls)
+ debug_printf(" - err %d '%s'\n", err, X509_verify_cert_error_string(err));
+ if (err == X509_V_ERR_APPLICATION_VERIFICATION)
+ preverify_ok = 1;
+ }
+return preverify_ok;
+}
+
+#endif /*EXPERIMENTAL_DANE*/
+
/*************************************************
* Information callback *
/* If dhparam is set, expand it, and load up the parameters for DH encryption.
Arguments:
- dhparam DH parameter file
+ sctx The current SSL CTX (inbound or outbound)
+ dhparam DH parameter file or fixed parameter identity string
host connected host, if client; NULL if server
+ errstr error string pointer
Returns: TRUE if OK (nothing to set up, or setup worked)
*/
static BOOL
-init_dh(uschar *dhparam, host_item *host)
+init_dh(SSL_CTX *sctx, uschar *dhparam, const host_item *host, uschar ** errstr)
{
-BOOL yield = TRUE;
BIO *bio;
DH *dh;
uschar *dhexpanded;
+const char *pem;
+int dh_bitsize;
-if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded))
+if (!expand_check(dhparam, US"tls_dhparam", &dhexpanded, errstr))
return FALSE;
-if (dhexpanded == NULL) return TRUE;
-
-if ((bio = BIO_new_file(CS dhexpanded, "r")) == NULL)
+if (!dhexpanded || !*dhexpanded)
+ bio = BIO_new_mem_buf(CS std_dh_prime_default(), -1);
+else if (dhexpanded[0] == '/')
{
- tls_error(string_sprintf("could not read dhparams file %s", dhexpanded),
- host, (uschar *)strerror(errno));
- yield = FALSE;
+ if (!(bio = BIO_new_file(CS dhexpanded, "r")))
+ {
+ tls_error(string_sprintf("could not read dhparams file %s", dhexpanded),
+ host, US strerror(errno), errstr);
+ return FALSE;
+ }
}
else
{
- if ((dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL)) == NULL)
+ if (Ustrcmp(dhexpanded, "none") == 0)
{
- tls_error(string_sprintf("could not read dhparams file %s", dhexpanded),
- host, NULL);
- yield = FALSE;
+ DEBUG(D_tls) debug_printf("Requested no DH parameters.\n");
+ return TRUE;
}
- else
+
+ if (!(pem = std_dh_prime_named(dhexpanded)))
{
- SSL_CTX_set_tmp_dh(ctx, dh);
- DEBUG(D_tls)
- debug_printf("Diffie-Hellman initialized from %s with %d-bit key\n",
- dhexpanded, 8*DH_size(dh));
- DH_free(dh);
+ tls_error(string_sprintf("Unknown standard DH prime \"%s\"", dhexpanded),
+ host, US strerror(errno), errstr);
+ return FALSE;
}
+ bio = BIO_new_mem_buf(CS pem, -1);
+ }
+
+if (!(dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL)))
+ {
BIO_free(bio);
+ tls_error(string_sprintf("Could not read tls_dhparams \"%s\"", dhexpanded),
+ host, NULL, errstr);
+ return FALSE;
+ }
+
+/* note: our default limit of 2236 is not a multiple of 8; the limit comes from
+ * an NSS limit, and the GnuTLS APIs handle bit-sizes fine, so we went with
+ * 2236. But older OpenSSL can only report in bytes (octets), not bits.
+ * If someone wants to dance at the edge, then they can raise the limit or use
+ * current libraries. */
+#ifdef EXIM_HAVE_OPENSSL_DH_BITS
+/* Added in commit 26c79d5641d; `git describe --contains` says OpenSSL_1_1_0-pre1~1022
+ * This predates OpenSSL_1_1_0 (before a, b, ...) so is in all 1.1.0 */
+dh_bitsize = DH_bits(dh);
+#else
+dh_bitsize = 8 * DH_size(dh);
+#endif
+
+/* Even if it is larger, we silently return success rather than cause things
+ * to fail out, so that a too-large DH will not knock out all TLS; it's a
+ * debatable choice. */
+if (dh_bitsize > tls_dh_max_bits)
+ {
+ DEBUG(D_tls)
+ debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d\n",
+ dh_bitsize, tls_dh_max_bits);
+ }
+else
+ {
+ SSL_CTX_set_tmp_dh(sctx, dh);
+ DEBUG(D_tls)
+ debug_printf("Diffie-Hellman initialized from %s with %d-bit prime\n",
+ dhexpanded ? dhexpanded : US"default", dh_bitsize);
+ }
+
+DH_free(dh);
+BIO_free(bio);
+
+return TRUE;
+}
+
+
+
+
+/*************************************************
+* Initialize for ECDH *
+*************************************************/
+
+/* Load parameters for ECDH encryption.
+
+For now, we stick to NIST P-256 because: it's simple and easy to configure;
+it avoids any patent issues that might bite redistributors; despite events in
+the news and concerns over curve choices, we're not cryptographers, we're not
+pretending to be, and this is "good enough" to be better than no support,
+protecting against most adversaries. Given another year or two, there might
+be sufficient clarity about a "right" way forward to let us make an informed
+decision, instead of a knee-jerk reaction.
+
+Longer-term, we should look at supporting both various named curves and
+external files generated with "openssl ecparam", much as we do for init_dh().
+We should also support "none" as a value, to explicitly avoid initialisation.
+
+Patches welcome.
+
+Arguments:
+ sctx The current SSL CTX (inbound or outbound)
+ host connected host, if client; NULL if server
+ errstr error string pointer
+
+Returns: TRUE if OK (nothing to set up, or setup worked)
+*/
+
+static BOOL
+init_ecdh(SSL_CTX * sctx, host_item * host, uschar ** errstr)
+{
+#ifdef OPENSSL_NO_ECDH
+return TRUE;
+#else
+
+EC_KEY * ecdh;
+uschar * exp_curve;
+int nid;
+BOOL rv;
+
+if (host) /* No ECDH setup for clients, only for servers */
+ return TRUE;
+
+# ifndef EXIM_HAVE_ECDH
+DEBUG(D_tls)
+ debug_printf("No OpenSSL API to define ECDH parameters, skipping\n");
+return TRUE;
+# else
+
+if (!expand_check(tls_eccurve, US"tls_eccurve", &exp_curve, errstr))
+ return FALSE;
+if (!exp_curve || !*exp_curve)
+ return TRUE;
+
+/* "auto" needs to be handled carefully.
+ * OpenSSL < 1.0.2: we do not select anything, but fallback to prime256v1
+ * OpenSSL < 1.1.0: we have to call SSL_CTX_set_ecdh_auto
+ * (openssl/ssl.h defines SSL_CTRL_SET_ECDH_AUTO)
+ * OpenSSL >= 1.1.0: we do not set anything, the libray does autoselection
+ * https://github.com/openssl/openssl/commit/fe6ef2472db933f01b59cad82aa925736935984b
+ */
+if (Ustrcmp(exp_curve, "auto") == 0)
+ {
+#if OPENSSL_VERSION_NUMBER < 0x10002000L
+ DEBUG(D_tls) debug_printf(
+ "ECDH OpenSSL < 1.0.2: temp key parameter settings: overriding \"auto\" with \"prime256v1\"\n");
+ exp_curve = US"prime256v1";
+#else
+# if defined SSL_CTRL_SET_ECDH_AUTO
+ DEBUG(D_tls) debug_printf(
+ "ECDH OpenSSL 1.0.2+ temp key parameter settings: autoselection\n");
+ SSL_CTX_set_ecdh_auto(sctx, 1);
+ return TRUE;
+# else
+ DEBUG(D_tls) debug_printf(
+ "ECDH OpenSSL 1.1.0+ temp key parameter settings: default selection\n");
+ return TRUE;
+# endif
+#endif
+ }
+
+DEBUG(D_tls) debug_printf("ECDH: curve '%s'\n", exp_curve);
+if ( (nid = OBJ_sn2nid (CCS exp_curve)) == NID_undef
+# ifdef EXIM_HAVE_OPENSSL_EC_NIST2NID
+ && (nid = EC_curve_nist2nid(CCS exp_curve)) == NID_undef
+# endif
+ )
+ {
+ tls_error(string_sprintf("Unknown curve name tls_eccurve '%s'", exp_curve),
+ host, NULL, errstr);
+ return FALSE;
+ }
+
+if (!(ecdh = EC_KEY_new_by_curve_name(nid)))
+ {
+ tls_error(US"Unable to create ec curve", host, NULL, errstr);
+ return FALSE;
+ }
+
+/* The "tmp" in the name here refers to setting a temporary key
+not to the stability of the interface. */
+
+if ((rv = SSL_CTX_set_tmp_ecdh(sctx, ecdh) == 0))
+ tls_error(string_sprintf("Error enabling '%s' curve", exp_curve), host, NULL, errstr);
+else
+ DEBUG(D_tls) debug_printf("ECDH: enabled '%s' curve\n", exp_curve);
+
+EC_KEY_free(ecdh);
+return !rv;
+
+# endif /*EXIM_HAVE_ECDH*/
+#endif /*OPENSSL_NO_ECDH*/
+}
+
+
+
+
+#ifndef DISABLE_OCSP
+/*************************************************
+* Load OCSP information into state *
+*************************************************/
+/* Called to load the server OCSP response from the given file into memory, once
+caller has determined this is needed. Checks validity. Debugs a message
+if invalid.
+
+ASSUMES: single response, for single cert.
+
+Arguments:
+ sctx the SSL_CTX* to update
+ cbinfo various parts of session state
+ expanded the filename putatively holding an OCSP response
+
+*/
+
+static void
+ocsp_load_response(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo, const uschar *expanded)
+{
+BIO * bio;
+OCSP_RESPONSE * resp;
+OCSP_BASICRESP * basic_response;
+OCSP_SINGLERESP * single_response;
+ASN1_GENERALIZEDTIME * rev, * thisupd, * nextupd;
+STACK_OF(X509) * sk;
+unsigned long verify_flags;
+int status, reason, i;
+
+cbinfo->u_ocsp.server.file_expanded = string_copy(expanded);
+if (cbinfo->u_ocsp.server.response)
+ {
+ OCSP_RESPONSE_free(cbinfo->u_ocsp.server.response);
+ cbinfo->u_ocsp.server.response = NULL;
+ }
+
+if (!(bio = BIO_new_file(CS cbinfo->u_ocsp.server.file_expanded, "rb")))
+ {
+ DEBUG(D_tls) debug_printf("Failed to open OCSP response file \"%s\"\n",
+ cbinfo->u_ocsp.server.file_expanded);
+ return;
+ }
+
+resp = d2i_OCSP_RESPONSE_bio(bio, NULL);
+BIO_free(bio);
+if (!resp)
+ {
+ DEBUG(D_tls) debug_printf("Error reading OCSP response.\n");
+ return;
+ }
+
+if ((status = OCSP_response_status(resp)) != OCSP_RESPONSE_STATUS_SUCCESSFUL)
+ {
+ DEBUG(D_tls) debug_printf("OCSP response not valid: %s (%d)\n",
+ OCSP_response_status_str(status), status);
+ goto bad;
+ }
+
+if (!(basic_response = OCSP_response_get1_basic(resp)))
+ {
+ DEBUG(D_tls)
+ debug_printf("OCSP response parse error: unable to extract basic response.\n");
+ goto bad;
+ }
+
+sk = cbinfo->verify_stack;
+verify_flags = OCSP_NOVERIFY; /* check sigs, but not purpose */
+
+/* May need to expose ability to adjust those flags?
+OCSP_NOSIGS OCSP_NOVERIFY OCSP_NOCHAIN OCSP_NOCHECKS OCSP_NOEXPLICIT
+OCSP_TRUSTOTHER OCSP_NOINTERN */
+
+/* This does a full verify on the OCSP proof before we load it for serving
+up; possibly overkill - just date-checks might be nice enough.
+
+OCSP_basic_verify takes a "store" arg, but does not
+use it for the chain verification, which is all we do
+when OCSP_NOVERIFY is set. The content from the wire
+"basic_response" and a cert-stack "sk" are all that is used.
+
+We have a stack, loaded in setup_certs() if tls_verify_certificates
+was a file (not a directory, or "system"). It is unfortunate we
+cannot used the connection context store, as that would neatly
+handle the "system" case too, but there seems to be no library
+function for getting a stack from a store.
+[ In OpenSSL 1.1 - ? X509_STORE_CTX_get0_chain(ctx) ? ]
+We do not free the stack since it could be needed a second time for
+SNI handling.
+
+Separately we might try to replace using OCSP_basic_verify() - which seems to not
+be a public interface into the OpenSSL library (there's no manual entry) -
+But what with? We also use OCSP_basic_verify in the client stapling callback.
+And there we NEED it; we must verify that status... unless the
+library does it for us anyway? */
+
+if ((i = OCSP_basic_verify(basic_response, sk, NULL, verify_flags)) < 0)
+ {
+ DEBUG(D_tls)
+ {
+ ERR_error_string(ERR_get_error(), ssl_errstring);
+ debug_printf("OCSP response verify failure: %s\n", US ssl_errstring);
+ }
+ goto bad;
}
-return yield;
+/* Here's the simplifying assumption: there's only one response, for the
+one certificate we use, and nothing for anything else in a chain. If this
+proves false, we need to extract a cert id from our issued cert
+(tls_certificate) and use that for OCSP_resp_find_status() (which finds the
+right cert in the stack and then calls OCSP_single_get0_status()).
+
+I'm hoping to avoid reworking a bunch more of how we handle state here. */
+
+if (!(single_response = OCSP_resp_get0(basic_response, 0)))
+ {
+ DEBUG(D_tls)
+ debug_printf("Unable to get first response from OCSP basic response.\n");
+ goto bad;
+ }
+
+status = OCSP_single_get0_status(single_response, &reason, &rev, &thisupd, &nextupd);
+if (status != V_OCSP_CERTSTATUS_GOOD)
+ {
+ DEBUG(D_tls) debug_printf("OCSP response bad cert status: %s (%d) %s (%d)\n",
+ OCSP_cert_status_str(status), status,
+ OCSP_crl_reason_str(reason), reason);
+ goto bad;
+ }
+
+if (!OCSP_check_validity(thisupd, nextupd, EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE))
+ {
+ DEBUG(D_tls) debug_printf("OCSP status invalid times.\n");
+ goto bad;
+ }
+
+supply_response:
+ cbinfo->u_ocsp.server.response = resp;
+return;
+
+bad:
+ if (running_in_test_harness)
+ {
+ extern char ** environ;
+ uschar ** p;
+ if (environ) for (p = USS environ; *p != NULL; p++)
+ if (Ustrncmp(*p, "EXIM_TESTHARNESS_DISABLE_OCSPVALIDITYCHECK", 42) == 0)
+ {
+ DEBUG(D_tls) debug_printf("Supplying known bad OCSP response\n");
+ goto supply_response;
+ }
+ }
+return;
+}
+#endif /*!DISABLE_OCSP*/
+
+
+
+
+/* Create and install a selfsigned certificate, for use in server mode */
+
+static int
+tls_install_selfsign(SSL_CTX * sctx, uschar ** errstr)
+{
+X509 * x509 = NULL;
+EVP_PKEY * pkey;
+RSA * rsa;
+X509_NAME * name;
+uschar * where;
+
+where = US"allocating pkey";
+if (!(pkey = EVP_PKEY_new()))
+ goto err;
+
+where = US"allocating cert";
+if (!(x509 = X509_new()))
+ goto err;
+
+where = US"generating pkey";
+ /* deprecated, use RSA_generate_key_ex() */
+if (!(rsa = RSA_generate_key(1024, RSA_F4, NULL, NULL)))
+ goto err;
+
+where = US"assigning pkey";
+if (!EVP_PKEY_assign_RSA(pkey, rsa))
+ goto err;
+
+X509_set_version(x509, 2); /* N+1 - version 3 */
+ASN1_INTEGER_set(X509_get_serialNumber(x509), 0);
+X509_gmtime_adj(X509_get_notBefore(x509), 0);
+X509_gmtime_adj(X509_get_notAfter(x509), (long)60 * 60); /* 1 hour */
+X509_set_pubkey(x509, pkey);
+
+name = X509_get_subject_name(x509);
+X509_NAME_add_entry_by_txt(name, "C",
+ MBSTRING_ASC, CUS "UK", -1, -1, 0);
+X509_NAME_add_entry_by_txt(name, "O",
+ MBSTRING_ASC, CUS "Exim Developers", -1, -1, 0);
+X509_NAME_add_entry_by_txt(name, "CN",
+ MBSTRING_ASC, CUS smtp_active_hostname, -1, -1, 0);
+X509_set_issuer_name(x509, name);
+
+where = US"signing cert";
+if (!X509_sign(x509, pkey, EVP_md5()))
+ goto err;
+
+where = US"installing selfsign cert";
+if (!SSL_CTX_use_certificate(sctx, x509))
+ goto err;
+
+where = US"installing selfsign key";
+if (!SSL_CTX_use_PrivateKey(sctx, pkey))
+ goto err;
+
+return OK;
+
+err:
+ (void) tls_error(where, NULL, NULL, errstr);
+ if (x509) X509_free(x509);
+ if (pkey) EVP_PKEY_free(pkey);
+ return DEFER;
}
* Expand key and cert file specs *
*************************************************/
-/* Called once during tls_init and possibly againt during TLS setup, for a
+/* Called once during tls_init and possibly again during TLS setup, for a
new context, if Server Name Indication was used and tls_sni was seen in
the certificate string.
Arguments:
sctx the SSL_CTX* to update
cbinfo various parts of session state
+ errstr error string pointer
Returns: OK/DEFER/FAIL
*/
static int
-tls_expand_session_files(SSL_CTX *sctx, const tls_ext_ctx_cb *cbinfo)
+tls_expand_session_files(SSL_CTX *sctx, tls_ext_ctx_cb *cbinfo,
+ uschar ** errstr)
{
uschar *expanded;
-if (cbinfo->certificate == NULL)
- return OK;
+if (!cbinfo->certificate)
+ {
+ if (cbinfo->host) /* client */
+ return OK;
+ /* server */
+ if (tls_install_selfsign(sctx, errstr) != OK)
+ return DEFER;
+ }
+else
+ {
+ if (Ustrstr(cbinfo->certificate, US"tls_sni") ||
+ Ustrstr(cbinfo->certificate, US"tls_in_sni") ||
+ Ustrstr(cbinfo->certificate, US"tls_out_sni")
+ )
+ reexpand_tls_files_for_sni = TRUE;
-if (Ustrstr(cbinfo->certificate, US"tls_sni"))
- reexpand_tls_files_for_sni = TRUE;
+ if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded, errstr))
+ return DEFER;
-if (!expand_check(cbinfo->certificate, US"tls_certificate", &expanded))
- return DEFER;
+ if (expanded != NULL)
+ {
+ DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded);
+ if (!SSL_CTX_use_certificate_chain_file(sctx, CS expanded))
+ return tls_error(string_sprintf(
+ "SSL_CTX_use_certificate_chain_file file=%s", expanded),
+ cbinfo->host, NULL, errstr);
+ }
-if (expanded != NULL)
- {
- DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded);
- if (!SSL_CTX_use_certificate_chain_file(sctx, CS expanded))
- return tls_error(string_sprintf(
- "SSL_CTX_use_certificate_chain_file file=%s", expanded),
- cbinfo->host, NULL);
- }
+ if (cbinfo->privatekey != NULL &&
+ !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded, errstr))
+ return DEFER;
-if (cbinfo->privatekey != NULL &&
- !expand_check(cbinfo->privatekey, US"tls_privatekey", &expanded))
- return DEFER;
+ /* If expansion was forced to fail, key_expanded will be NULL. If the result
+ of the expansion is an empty string, ignore it also, and assume the private
+ key is in the same file as the certificate. */
-/* If expansion was forced to fail, key_expanded will be NULL. If the result
-of the expansion is an empty string, ignore it also, and assume the private
-key is in the same file as the certificate. */
+ if (expanded && *expanded)
+ {
+ DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded);
+ if (!SSL_CTX_use_PrivateKey_file(sctx, CS expanded, SSL_FILETYPE_PEM))
+ return tls_error(string_sprintf(
+ "SSL_CTX_use_PrivateKey_file file=%s", expanded), cbinfo->host, NULL, errstr);
+ }
+ }
-if (expanded != NULL && *expanded != 0)
+#ifndef DISABLE_OCSP
+if (cbinfo->is_server && cbinfo->u_ocsp.server.file)
{
- DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded);
- if (!SSL_CTX_use_PrivateKey_file(sctx, CS expanded, SSL_FILETYPE_PEM))
- return tls_error(string_sprintf(
- "SSL_CTX_use_PrivateKey_file file=%s", expanded), cbinfo->host, NULL);
+ if (!expand_check(cbinfo->u_ocsp.server.file, US"tls_ocsp_file", &expanded, errstr))
+ return DEFER;
+
+ if (expanded && *expanded)
+ {
+ DEBUG(D_tls) debug_printf("tls_ocsp_file %s\n", expanded);
+ if ( cbinfo->u_ocsp.server.file_expanded
+ && (Ustrcmp(expanded, cbinfo->u_ocsp.server.file_expanded) == 0))
+ {
+ DEBUG(D_tls) debug_printf(" - value unchanged, using existing values\n");
+ }
+ else
+ ocsp_load_response(sctx, cbinfo, expanded);
+ }
}
+#endif
return OK;
}
Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK}
*/
-static int
-tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg);
-/* pre-declared for SSL_CTX_set_tlsext_servername_callback call within func */
-
+#ifdef EXIM_HAVE_OPENSSL_TLSEXT
static int
tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg)
{
const char *servername = SSL_get_servername(s, TLSEXT_NAMETYPE_host_name);
-const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg;
+tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg;
int rc;
int old_pool = store_pool;
+uschar * dummy_errstr;
if (!servername)
return SSL_TLSEXT_ERR_OK;
/* Make the extension value available for expansion */
store_pool = POOL_PERM;
-tls_sni = string_copy(US servername);
+tls_in.sni = string_copy(US servername);
store_pool = old_pool;
if (!reexpand_tls_files_for_sni)
not confident that memcpy wouldn't break some internal reference counting.
Especially since there's a references struct member, which would be off. */
-ctx_sni = SSL_CTX_new(SSLv23_server_method());
-if (!ctx_sni)
+if (!(server_sni = SSL_CTX_new(SSLv23_server_method())))
{
ERR_error_string(ERR_get_error(), ssl_errstring);
DEBUG(D_tls) debug_printf("SSL_CTX_new() failed: %s\n", ssl_errstring);
/* Not sure how many of these are actually needed, since SSL object
already exists. Might even need this selfsame callback, for reneg? */
-SSL_CTX_set_info_callback(ctx_sni, SSL_CTX_get_info_callback(ctx));
-SSL_CTX_set_mode(ctx_sni, SSL_CTX_get_mode(ctx));
-SSL_CTX_set_options(ctx_sni, SSL_CTX_get_options(ctx));
-SSL_CTX_set_timeout(ctx_sni, SSL_CTX_get_timeout(ctx));
-SSL_CTX_set_tlsext_servername_callback(ctx_sni, tls_servername_cb);
-SSL_CTX_set_tlsext_servername_arg(ctx_sni, cbinfo);
+SSL_CTX_set_info_callback(server_sni, SSL_CTX_get_info_callback(server_ctx));
+SSL_CTX_set_mode(server_sni, SSL_CTX_get_mode(server_ctx));
+SSL_CTX_set_options(server_sni, SSL_CTX_get_options(server_ctx));
+SSL_CTX_set_timeout(server_sni, SSL_CTX_get_timeout(server_ctx));
+SSL_CTX_set_tlsext_servername_callback(server_sni, tls_servername_cb);
+SSL_CTX_set_tlsext_servername_arg(server_sni, cbinfo);
+
+if ( !init_dh(server_sni, cbinfo->dhparam, NULL, &dummy_errstr)
+ || !init_ecdh(server_sni, NULL, &dummy_errstr)
+ )
+ return SSL_TLSEXT_ERR_NOACK;
+
if (cbinfo->server_cipher_list)
- SSL_CTX_set_cipher_list(ctx_sni, CS cbinfo->server_cipher_list);
+ SSL_CTX_set_cipher_list(server_sni, CS cbinfo->server_cipher_list);
+#ifndef DISABLE_OCSP
+if (cbinfo->u_ocsp.server.file)
+ {
+ SSL_CTX_set_tlsext_status_cb(server_sni, tls_server_stapling_cb);
+ SSL_CTX_set_tlsext_status_arg(server_sni, cbinfo);
+ }
+#endif
-rc = tls_expand_session_files(ctx_sni, cbinfo);
-if (rc != OK) return SSL_TLSEXT_ERR_NOACK;
+if ((rc = setup_certs(server_sni, tls_verify_certificates, tls_crl, NULL, FALSE,
+ verify_callback_server, &dummy_errstr)) != OK)
+ return SSL_TLSEXT_ERR_NOACK;
-rc = setup_certs(ctx_sni, tls_verify_certificates, tls_crl, NULL, FALSE);
-if (rc != OK) return SSL_TLSEXT_ERR_NOACK;
+/* do this after setup_certs, because this can require the certs for verifying
+OCSP information. */
+if ((rc = tls_expand_session_files(server_sni, cbinfo, &dummy_errstr)) != OK)
+ return SSL_TLSEXT_ERR_NOACK;
DEBUG(D_tls) debug_printf("Switching SSL context.\n");
-SSL_set_SSL_CTX(s, ctx_sni);
+SSL_set_SSL_CTX(s, server_sni);
return SSL_TLSEXT_ERR_OK;
}
+#endif /* EXIM_HAVE_OPENSSL_TLSEXT */
+
+#ifndef DISABLE_OCSP
+
+/*************************************************
+* Callback to handle OCSP Stapling *
+*************************************************/
+
+/* Called when acting as server during the TLS session setup if the client
+requests OCSP information with a Certificate Status Request.
+
+Documentation via openssl s_server.c and the Apache patch from the OpenSSL
+project.
+
+*/
+
+static int
+tls_server_stapling_cb(SSL *s, void *arg)
+{
+const tls_ext_ctx_cb *cbinfo = (tls_ext_ctx_cb *) arg;
+uschar *response_der;
+int response_der_len;
+
+DEBUG(D_tls)
+ debug_printf("Received TLS status request (OCSP stapling); %s response\n",
+ cbinfo->u_ocsp.server.response ? "have" : "lack");
+
+tls_in.ocsp = OCSP_NOT_RESP;
+if (!cbinfo->u_ocsp.server.response)
+ return SSL_TLSEXT_ERR_NOACK;
+
+response_der = NULL;
+response_der_len = i2d_OCSP_RESPONSE(cbinfo->u_ocsp.server.response,
+ &response_der);
+if (response_der_len <= 0)
+ return SSL_TLSEXT_ERR_NOACK;
+
+SSL_set_tlsext_status_ocsp_resp(server_ssl, response_der, response_der_len);
+tls_in.ocsp = OCSP_VFIED;
+return SSL_TLSEXT_ERR_OK;
+}
+
+
+static void
+time_print(BIO * bp, const char * str, ASN1_GENERALIZEDTIME * time)
+{
+BIO_printf(bp, "\t%s: ", str);
+ASN1_GENERALIZEDTIME_print(bp, time);
+BIO_puts(bp, "\n");
+}
+
+static int
+tls_client_stapling_cb(SSL *s, void *arg)
+{
+tls_ext_ctx_cb * cbinfo = arg;
+const unsigned char * p;
+int len;
+OCSP_RESPONSE * rsp;
+OCSP_BASICRESP * bs;
+int i;
+
+DEBUG(D_tls) debug_printf("Received TLS status response (OCSP stapling):");
+len = SSL_get_tlsext_status_ocsp_resp(s, &p);
+if(!p)
+ {
+ /* Expect this when we requested ocsp but got none */
+ if (cbinfo->u_ocsp.client.verify_required && LOGGING(tls_cipher))
+ log_write(0, LOG_MAIN, "Received TLS status callback, null content");
+ else
+ DEBUG(D_tls) debug_printf(" null\n");
+ return cbinfo->u_ocsp.client.verify_required ? 0 : 1;
+ }
+
+if(!(rsp = d2i_OCSP_RESPONSE(NULL, &p, len)))
+ {
+ tls_out.ocsp = OCSP_FAILED;
+ if (LOGGING(tls_cipher))
+ log_write(0, LOG_MAIN, "Received TLS cert status response, parse error");
+ else
+ DEBUG(D_tls) debug_printf(" parse error\n");
+ return 0;
+ }
+
+if(!(bs = OCSP_response_get1_basic(rsp)))
+ {
+ tls_out.ocsp = OCSP_FAILED;
+ if (LOGGING(tls_cipher))
+ log_write(0, LOG_MAIN, "Received TLS cert status response, error parsing response");
+ else
+ DEBUG(D_tls) debug_printf(" error parsing response\n");
+ OCSP_RESPONSE_free(rsp);
+ return 0;
+ }
+
+/* We'd check the nonce here if we'd put one in the request. */
+/* However that would defeat cacheability on the server so we don't. */
+
+/* This section of code reworked from OpenSSL apps source;
+ The OpenSSL Project retains copyright:
+ Copyright (c) 1999 The OpenSSL Project. All rights reserved.
+*/
+ {
+ BIO * bp = NULL;
+ int status, reason;
+ ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd;
+
+ DEBUG(D_tls) bp = BIO_new_fp(stderr, BIO_NOCLOSE);
+
+ /*OCSP_RESPONSE_print(bp, rsp, 0); extreme debug: stapling content */
+
+ /* Use the chain that verified the server cert to verify the stapled info */
+ /* DEBUG(D_tls) x509_store_dump_cert_s_names(cbinfo->u_ocsp.client.verify_store); */
+
+ if ((i = OCSP_basic_verify(bs, cbinfo->verify_stack,
+ cbinfo->u_ocsp.client.verify_store, 0)) <= 0)
+ {
+ tls_out.ocsp = OCSP_FAILED;
+ if (LOGGING(tls_cipher))
+ log_write(0, LOG_MAIN, "Received TLS cert status response, itself unverifiable");
+ BIO_printf(bp, "OCSP response verify failure\n");
+ ERR_print_errors(bp);
+ goto failed;
+ }
+
+ BIO_printf(bp, "OCSP response well-formed and signed OK\n");
+
+ /*XXX So we have a good stapled OCSP status. How do we know
+ it is for the cert of interest? OpenSSL 1.1.0 has a routine
+ OCSP_resp_find_status() which matches on a cert id, which presumably
+ we should use. Making an id needs OCSP_cert_id_new(), which takes
+ issuerName, issuerKey, serialNumber. Are they all in the cert?
+
+ For now, carry on blindly accepting the resp. */
+
+ {
+ OCSP_SINGLERESP * single;
+
+#ifdef EXIM_HAVE_OCSP_RESP_COUNT
+ if (OCSP_resp_count(bs) != 1)
+#else
+ STACK_OF(OCSP_SINGLERESP) * sresp = bs->tbsResponseData->responses;
+ if (sk_OCSP_SINGLERESP_num(sresp) != 1)
+#endif
+ {
+ tls_out.ocsp = OCSP_FAILED;
+ log_write(0, LOG_MAIN, "OCSP stapling "
+ "with multiple responses not handled");
+ goto failed;
+ }
+ single = OCSP_resp_get0(bs, 0);
+ status = OCSP_single_get0_status(single, &reason, &rev,
+ &thisupd, &nextupd);
+ }
+
+ DEBUG(D_tls) time_print(bp, "This OCSP Update", thisupd);
+ DEBUG(D_tls) if(nextupd) time_print(bp, "Next OCSP Update", nextupd);
+ if (!OCSP_check_validity(thisupd, nextupd,
+ EXIM_OCSP_SKEW_SECONDS, EXIM_OCSP_MAX_AGE))
+ {
+ tls_out.ocsp = OCSP_FAILED;
+ DEBUG(D_tls) ERR_print_errors(bp);
+ log_write(0, LOG_MAIN, "Server OSCP dates invalid");
+ }
+ else
+ {
+ DEBUG(D_tls) BIO_printf(bp, "Certificate status: %s\n",
+ OCSP_cert_status_str(status));
+ switch(status)
+ {
+ case V_OCSP_CERTSTATUS_GOOD:
+ tls_out.ocsp = OCSP_VFIED;
+ i = 1;
+ goto good;
+ case V_OCSP_CERTSTATUS_REVOKED:
+ tls_out.ocsp = OCSP_FAILED;
+ log_write(0, LOG_MAIN, "Server certificate revoked%s%s",
+ reason != -1 ? "; reason: " : "",
+ reason != -1 ? OCSP_crl_reason_str(reason) : "");
+ DEBUG(D_tls) time_print(bp, "Revocation Time", rev);
+ break;
+ default:
+ tls_out.ocsp = OCSP_FAILED;
+ log_write(0, LOG_MAIN,
+ "Server certificate status unknown, in OCSP stapling");
+ break;
+ }
+ }
+ failed:
+ i = cbinfo->u_ocsp.client.verify_required ? 0 : 1;
+ good:
+ BIO_free(bp);
+ }
+
+OCSP_RESPONSE_free(rsp);
+return i;
+}
+#endif /*!DISABLE_OCSP*/
+
/*************************************************
* Initialize for TLS *
*************************************************/
-/* Called from both server and client code, to do preliminary initialization of
-the library.
+/* Called from both server and client code, to do preliminary initialization
+of the library. We allocate and return a context structure.
Arguments:
+ ctxp returned SSL context
host connected host, if client; NULL if server
dhparam DH parameter file
certificate certificate file
privatekey private key
+ ocsp_file file of stapling info (server); flag for require ocsp (client)
addr address if client; NULL if server (for some randomness)
+ cbp place to put allocated callback context
+ errstr error string pointer
Returns: OK/DEFER/FAIL
*/
static int
-tls_init(host_item *host, uschar *dhparam, uschar *certificate,
- uschar *privatekey, address_item *addr)
+tls_init(SSL_CTX **ctxp, host_item *host, uschar *dhparam, uschar *certificate,
+ uschar *privatekey,
+#ifndef DISABLE_OCSP
+ uschar *ocsp_file,
+#endif
+ address_item *addr, tls_ext_ctx_cb ** cbp, uschar ** errstr)
{
+SSL_CTX * ctx;
long init_options;
int rc;
-BOOL okay;
-tls_ext_ctx_cb *cbinfo;
+tls_ext_ctx_cb * cbinfo;
cbinfo = store_malloc(sizeof(tls_ext_ctx_cb));
cbinfo->certificate = certificate;
cbinfo->privatekey = privatekey;
+#ifndef DISABLE_OCSP
+cbinfo->verify_stack = NULL;
+if ((cbinfo->is_server = host==NULL))
+ {
+ cbinfo->u_ocsp.server.file = ocsp_file;
+ cbinfo->u_ocsp.server.file_expanded = NULL;
+ cbinfo->u_ocsp.server.response = NULL;
+ }
+else
+ cbinfo->u_ocsp.client.verify_store = NULL;
+#endif
cbinfo->dhparam = dhparam;
+cbinfo->server_cipher_list = NULL;
cbinfo->host = host;
+#ifndef DISABLE_EVENT
+cbinfo->event_action = NULL;
+#endif
SSL_load_error_strings(); /* basic set up */
OpenSSL_add_ssl_algorithms();
-#if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256)
+#ifdef EXIM_HAVE_SHA256
/* SHA256 is becoming ever more popular. This makes sure it gets added to the
list of available digests. */
EVP_add_digest(EVP_sha256());
#endif
-/* Create a context */
-
-ctx = SSL_CTX_new((host == NULL)?
- SSLv23_server_method() : SSLv23_client_method());
+/* Create a context.
+The OpenSSL docs in 1.0.1b have not been updated to clarify TLS variant
+negotiation in the different methods; as far as I can tell, the only
+*_{server,client}_method which allows negotiation is SSLv23, which exists even
+when OpenSSL is built without SSLv2 support.
+By disabling with openssl_options, we can let admins re-enable with the
+existing knob. */
-if (ctx == NULL) return tls_error(US"SSL_CTX_new", host, NULL);
+if (!(ctx = SSL_CTX_new(host ? SSLv23_client_method() : SSLv23_server_method())))
+ return tls_error(US"SSL_CTX_new", host, NULL, errstr);
/* It turns out that we need to seed the random number generator this early in
order to get the full complement of ciphers to work. It took me roughly a day
gettimeofday(&r.tv, NULL);
r.p = getpid();
- RAND_seed((uschar *)(&r), sizeof(r));
- RAND_seed((uschar *)big_buffer, big_buffer_size);
- if (addr != NULL) RAND_seed((uschar *)addr, sizeof(addr));
+ RAND_seed(US (&r), sizeof(r));
+ RAND_seed(US big_buffer, big_buffer_size);
+ if (addr != NULL) RAND_seed(US addr, sizeof(addr));
if (!RAND_status())
return tls_error(US"RAND_status", host,
- US"unable to seed random number generator");
+ US"unable to seed random number generator", errstr);
}
/* Set up the information callback, which outputs if debugging is at a suitable
level. */
-SSL_CTX_set_info_callback(ctx, (void (*)())info_callback);
+DEBUG(D_tls) SSL_CTX_set_info_callback(ctx, (void (*)())info_callback);
/* Automatically re-try reads/writes after renegotiation. */
(void) SSL_CTX_set_mode(ctx, SSL_MODE_AUTO_RETRY);
No OpenSSL version number checks: the options we accept depend upon the
availability of the option value macros from OpenSSL. */
-okay = tls_openssl_options_parse(openssl_options, &init_options);
-if (!okay)
- return tls_error(US"openssl_options parsing failed", host, NULL);
+if (!tls_openssl_options_parse(openssl_options, &init_options))
+ return tls_error(US"openssl_options parsing failed", host, NULL, errstr);
if (init_options)
{
DEBUG(D_tls) debug_printf("setting SSL CTX options: %#lx\n", init_options);
if (!(SSL_CTX_set_options(ctx, init_options)))
return tls_error(string_sprintf(
- "SSL_CTX_set_option(%#lx)", init_options), host, NULL);
+ "SSL_CTX_set_option(%#lx)", init_options), host, NULL, errstr);
}
else
DEBUG(D_tls) debug_printf("no SSL CTX options to set\n");
+/* Disable session cache unconditionally */
+
+(void) SSL_CTX_set_session_cache_mode(ctx, SSL_SESS_CACHE_OFF);
+
/* Initialize with DH parameters if supplied */
+/* Initialize ECDH temp key parameter selection */
+
+if ( !init_dh(ctx, dhparam, host, errstr)
+ || !init_ecdh(ctx, host, errstr)
+ )
+ return DEFER;
-if (!init_dh(dhparam, host)) return DEFER;
+/* Set up certificate and key (and perhaps OCSP info) */
-/* Set up certificate and key */
+if ((rc = tls_expand_session_files(ctx, cbinfo, errstr)) != OK)
+ return rc;
-rc = tls_expand_session_files(ctx, cbinfo);
-if (rc != OK) return rc;
+/* If we need to handle SNI or OCSP, do so */
-/* If we need to handle SNI, do so */
-#if OPENSSL_VERSION_NUMBER >= 0x0090806fL && !defined(OPENSSL_NO_TLSEXT)
-if (host == NULL)
+#ifdef EXIM_HAVE_OPENSSL_TLSEXT
+# ifndef DISABLE_OCSP
+ if (!(cbinfo->verify_stack = sk_X509_new_null()))
+ {
+ DEBUG(D_tls) debug_printf("failed to create stack for stapling verify\n");
+ return FAIL;
+ }
+# endif
+
+if (host == NULL) /* server */
{
+# ifndef DISABLE_OCSP
+ /* We check u_ocsp.server.file, not server.response, because we care about if
+ the option exists, not what the current expansion might be, as SNI might
+ change the certificate and OCSP file in use between now and the time the
+ callback is invoked. */
+ if (cbinfo->u_ocsp.server.file)
+ {
+ SSL_CTX_set_tlsext_status_cb(ctx, tls_server_stapling_cb);
+ SSL_CTX_set_tlsext_status_arg(ctx, cbinfo);
+ }
+# endif
/* We always do this, so that $tls_sni is available even if not used in
tls_certificate */
SSL_CTX_set_tlsext_servername_callback(ctx, tls_servername_cb);
SSL_CTX_set_tlsext_servername_arg(ctx, cbinfo);
}
+# ifndef DISABLE_OCSP
+else /* client */
+ if(ocsp_file) /* wanting stapling */
+ {
+ if (!(cbinfo->u_ocsp.client.verify_store = X509_STORE_new()))
+ {
+ DEBUG(D_tls) debug_printf("failed to create store for stapling verify\n");
+ return FAIL;
+ }
+ SSL_CTX_set_tlsext_status_cb(ctx, tls_client_stapling_cb);
+ SSL_CTX_set_tlsext_status_arg(ctx, cbinfo);
+ }
+# endif
#endif
-/* Set up the RSA callback */
+cbinfo->verify_cert_hostnames = NULL;
+#ifdef EXIM_HAVE_EPHEM_RSA_KEX
+/* Set up the RSA callback */
SSL_CTX_set_tmp_rsa_callback(ctx, rsa_callback);
+#endif
/* Finally, set the timeout, and we are done */
SSL_CTX_set_timeout(ctx, ssl_session_timeout);
DEBUG(D_tls) debug_printf("Initialized TLS\n");
-static_cbinfo = cbinfo;
+*cbp = cbinfo;
+*ctxp = ctx;
return OK;
}
* Get name of cipher in use *
*************************************************/
-/* The answer is left in a static buffer, and tls_cipher is set to point
-to it.
-
+/*
Argument: pointer to an SSL structure for the connection
+ buffer to use for answer
+ size of buffer
+ pointer to number of bits for cipher
Returns: nothing
*/
static void
-construct_cipher_name(SSL *ssl)
+construct_cipher_name(SSL *ssl, uschar *cipherbuf, int bsize, int *bits)
{
-static uschar cipherbuf[256];
/* With OpenSSL 1.0.0a, this needs to be const but the documentation doesn't
yet reflect that. It should be a safe change anyway, even 0.9.8 versions have
the accessor functions use const in the prototype. */
const SSL_CIPHER *c;
-uschar *ver;
-
-switch (ssl->session->ssl_version)
- {
- case SSL2_VERSION:
- ver = US"SSLv2";
- break;
+const uschar *ver;
- case SSL3_VERSION:
- ver = US"SSLv3";
- break;
-
- case TLS1_VERSION:
- ver = US"TLSv1";
- break;
-
-#ifdef TLS1_1_VERSION
- case TLS1_1_VERSION:
- ver = US"TLSv1.1";
- break;
-#endif
+ver = (const uschar *)SSL_get_version(ssl);
-#ifdef TLS1_2_VERSION
- case TLS1_2_VERSION:
- ver = US"TLSv1.2";
- break;
-#endif
+c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl);
+SSL_CIPHER_get_bits(c, bits);
- default:
- ver = US"UNKNOWN";
- }
+string_format(cipherbuf, bsize, "%s:%s:%u", ver,
+ SSL_CIPHER_get_name(c), *bits);
-c = (const SSL_CIPHER *) SSL_get_current_cipher(ssl);
-SSL_CIPHER_get_bits(c, &tls_bits);
+DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf);
+}
-string_format(cipherbuf, sizeof(cipherbuf), "%s:%s:%u", ver,
- SSL_CIPHER_get_name(c), tls_bits);
-tls_cipher = cipherbuf;
-DEBUG(D_tls) debug_printf("Cipher: %s\n", cipherbuf);
+static void
+peer_cert(SSL * ssl, tls_support * tlsp, uschar * peerdn, unsigned bsize)
+{
+/*XXX we might consider a list-of-certs variable for the cert chain.
+SSL_get_peer_cert_chain(SSL*). We'd need a new variable type and support
+in list-handling functions, also consider the difference between the entire
+chain and the elements sent by the peer. */
+
+/* Will have already noted peercert on a verify fail; possibly not the leaf */
+if (!tlsp->peercert)
+ tlsp->peercert = SSL_get_peer_certificate(ssl);
+/* Beware anonymous ciphers which lead to server_cert being NULL */
+if (tlsp->peercert)
+ {
+ X509_NAME_oneline(X509_get_subject_name(tlsp->peercert), CS peerdn, bsize);
+ peerdn[bsize-1] = '\0';
+ tlsp->peerdn = peerdn; /*XXX a static buffer... */
+ }
+else
+ tlsp->peerdn = NULL;
}
* Set up for verifying certificates *
*************************************************/
+/* Load certs from file, return TRUE on success */
+
+static BOOL
+chain_from_pem_file(const uschar * file, STACK_OF(X509) * verify_stack)
+{
+BIO * bp;
+X509 * x;
+
+if (!(bp = BIO_new_file(CS file, "r"))) return FALSE;
+while ((x = PEM_read_bio_X509(bp, NULL, 0, NULL)))
+ sk_X509_push(verify_stack, x);
+BIO_free(bp);
+return TRUE;
+}
+
+
+
/* Called by both client and server startup
Arguments:
host NULL in a server; the remote host in a client
optional TRUE if called from a server for a host in tls_try_verify_hosts;
otherwise passed as FALSE
+ cert_vfy_cb Callback function for certificate verification
+ errstr error string pointer
Returns: OK/DEFER/FAIL
*/
static int
-setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional)
+setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional,
+ int (*cert_vfy_cb)(int, X509_STORE_CTX *), uschar ** errstr)
{
uschar *expcerts, *expcrl;
-if (!expand_check(certs, US"tls_verify_certificates", &expcerts))
+if (!expand_check(certs, US"tls_verify_certificates", &expcerts, errstr))
return DEFER;
+DEBUG(D_tls) debug_printf("tls_verify_certificates: %s\n", expcerts);
-if (expcerts != NULL)
+if (expcerts && *expcerts)
{
- struct stat statbuf;
+ /* Tell the library to use its compiled-in location for the system default
+ CA bundle. Then add the ones specified in the config, if any. */
+
if (!SSL_CTX_set_default_verify_paths(sctx))
- return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL);
+ return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL, errstr);
- if (Ustat(expcerts, &statbuf) < 0)
- {
- log_write(0, LOG_MAIN|LOG_PANIC,
- "failed to stat %s for certificates", expcerts);
- return DEFER;
- }
- else
+ if (Ustrcmp(expcerts, "system") != 0)
{
- uschar *file, *dir;
- if ((statbuf.st_mode & S_IFMT) == S_IFDIR)
- { file = NULL; dir = expcerts; }
- else
- { file = expcerts; dir = NULL; }
-
- /* If a certificate file is empty, the next function fails with an
- unhelpful error message. If we skip it, we get the correct behaviour (no
- certificates are recognized, but the error message is still misleading (it
- says no certificate was supplied.) But this is better. */
-
- if ((file == NULL || statbuf.st_size > 0) &&
- !SSL_CTX_load_verify_locations(sctx, CS file, CS dir))
- return tls_error(US"SSL_CTX_load_verify_locations", host, NULL);
+ struct stat statbuf;
- if (file != NULL)
+ if (Ustat(expcerts, &statbuf) < 0)
{
- SSL_CTX_set_client_CA_list(sctx, SSL_load_client_CA_file(CS file));
+ log_write(0, LOG_MAIN|LOG_PANIC,
+ "failed to stat %s for certificates", expcerts);
+ return DEFER;
+ }
+ else
+ {
+ uschar *file, *dir;
+ if ((statbuf.st_mode & S_IFMT) == S_IFDIR)
+ { file = NULL; dir = expcerts; }
+ else
+ {
+ file = expcerts; dir = NULL;
+#ifndef DISABLE_OCSP
+ /* In the server if we will be offering an OCSP proof, load chain from
+ file for verifying the OCSP proof at load time. */
+
+ if ( !host
+ && statbuf.st_size > 0
+ && server_static_cbinfo->u_ocsp.server.file
+ && !chain_from_pem_file(file, server_static_cbinfo->verify_stack)
+ )
+ {
+ log_write(0, LOG_MAIN|LOG_PANIC,
+ "failed to load cert hain from %s", file);
+ return DEFER;
+ }
+#endif
+ }
+
+ /* If a certificate file is empty, the next function fails with an
+ unhelpful error message. If we skip it, we get the correct behaviour (no
+ certificates are recognized, but the error message is still misleading (it
+ says no certificate was supplied). But this is better. */
+
+ if ( (!file || statbuf.st_size > 0)
+ && !SSL_CTX_load_verify_locations(sctx, CS file, CS dir))
+ return tls_error(US"SSL_CTX_load_verify_locations", host, NULL, errstr);
+
+ /* Load the list of CAs for which we will accept certs, for sending
+ to the client. This is only for the one-file tls_verify_certificates
+ variant.
+ If a list isn't loaded into the server, but
+ some verify locations are set, the server end appears to make
+ a wildcard request for client certs.
+ Meanwhile, the client library as default behaviour *ignores* the list
+ we send over the wire - see man SSL_CTX_set_client_cert_cb.
+ Because of this, and that the dir variant is likely only used for
+ the public-CA bundle (not for a private CA), not worth fixing.
+ */
+ if (file)
+ {
+ STACK_OF(X509_NAME) * names = SSL_load_client_CA_file(CS file);
+
+ DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n",
+ sk_X509_NAME_num(names));
+ SSL_CTX_set_client_CA_list(sctx, names);
+ }
}
}
/* Handle a certificate revocation list. */
- #if OPENSSL_VERSION_NUMBER > 0x00907000L
+#if OPENSSL_VERSION_NUMBER > 0x00907000L
/* This bit of code is now the version supplied by Lars Mainka. (I have
- * merely reformatted it into the Exim code style.)
+ merely reformatted it into the Exim code style.)
- * "From here I changed the code to add support for multiple crl's
- * in pem format in one file or to support hashed directory entries in
- * pem format instead of a file. This method now uses the library function
- * X509_STORE_load_locations to add the CRL location to the SSL context.
- * OpenSSL will then handle the verify against CA certs and CRLs by
- * itself in the verify callback." */
+ "From here I changed the code to add support for multiple crl's
+ in pem format in one file or to support hashed directory entries in
+ pem format instead of a file. This method now uses the library function
+ X509_STORE_load_locations to add the CRL location to the SSL context.
+ OpenSSL will then handle the verify against CA certs and CRLs by
+ itself in the verify callback." */
- if (!expand_check(crl, US"tls_crl", &expcrl)) return DEFER;
- if (expcrl != NULL && *expcrl != 0)
+ if (!expand_check(crl, US"tls_crl", &expcrl, errstr)) return DEFER;
+ if (expcrl && *expcrl)
{
struct stat statbufcrl;
if (Ustat(expcrl, &statbufcrl) < 0)
DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file);
}
if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0)
- return tls_error(US"X509_STORE_load_locations", host, NULL);
+ return tls_error(US"X509_STORE_load_locations", host, NULL, errstr);
/* setting the flags to check against the complete crl chain */
}
}
- #endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */
+#endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */
/* If verification is optional, don't fail if no certificate */
SSL_CTX_set_verify(sctx,
SSL_VERIFY_PEER | (optional? 0 : SSL_VERIFY_FAIL_IF_NO_PEER_CERT),
- verify_callback);
+ cert_vfy_cb);
}
return OK;
Arguments:
require_ciphers allowed ciphers
- ------------------------------------------------------
- require_mac list of allowed MACs ) Not used
- require_kx list of allowed key_exchange methods ) for
- require_proto list of allowed protocols ) OpenSSL
- ------------------------------------------------------
+ errstr pointer to error message
Returns: OK on success
DEFER for errors before the start of the negotiation
- FAIL for errors during the negotation; the server can't
+ FAIL for errors during the negotiation; the server can't
continue running.
*/
int
-tls_server_start(uschar *require_ciphers, uschar *require_mac,
- uschar *require_kx, uschar *require_proto)
+tls_server_start(const uschar * require_ciphers, uschar ** errstr)
{
int rc;
-uschar *expciphers;
-tls_ext_ctx_cb *cbinfo;
+uschar * expciphers;
+tls_ext_ctx_cb * cbinfo;
+static uschar peerdn[256];
+static uschar cipherbuf[256];
/* Check for previous activation */
-if (tls_active >= 0)
+if (tls_in.active >= 0)
{
- tls_error(US"STARTTLS received after TLS started", NULL, US"");
- smtp_printf("554 Already in TLS\r\n");
+ tls_error(US"STARTTLS received after TLS started", NULL, US"", errstr);
+ smtp_printf("554 Already in TLS\r\n", FALSE);
return FAIL;
}
/* Initialize the SSL library. If it fails, it will already have logged
the error. */
-rc = tls_init(NULL, tls_dhparam, tls_certificate, tls_privatekey, NULL);
+rc = tls_init(&server_ctx, NULL, tls_dhparam, tls_certificate, tls_privatekey,
+#ifndef DISABLE_OCSP
+ tls_ocsp_file,
+#endif
+ NULL, &server_static_cbinfo, errstr);
if (rc != OK) return rc;
-cbinfo = static_cbinfo;
+cbinfo = server_static_cbinfo;
-if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers))
+if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers, errstr))
return FAIL;
/* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they
-are separated by underscores. So that I can use either form in my tests, and
-also for general convenience, we turn underscores into hyphens here. */
+were historically separated by underscores. So that I can use either form in my
+tests, and also for general convenience, we turn underscores into hyphens here.
+*/
-if (expciphers != NULL)
+if (expciphers)
{
- uschar *s = expciphers;
+ uschar * s = expciphers;
while (*s != 0) { if (*s == '_') *s = '-'; s++; }
DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers);
- if (!SSL_CTX_set_cipher_list(ctx, CS expciphers))
- return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL);
+ if (!SSL_CTX_set_cipher_list(server_ctx, CS expciphers))
+ return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL, errstr);
cbinfo->server_cipher_list = expciphers;
}
/* If this is a host for which certificate verification is mandatory or
optional, set up appropriately. */
-tls_certificate_verified = FALSE;
-verify_callback_called = FALSE;
+tls_in.certificate_verified = FALSE;
+#ifdef EXPERIMENTAL_DANE
+tls_in.dane_verified = FALSE;
+#endif
+server_verify_callback_called = FALSE;
if (verify_check_host(&tls_verify_hosts) == OK)
{
- rc = setup_certs(ctx, tls_verify_certificates, tls_crl, NULL, FALSE);
+ rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL,
+ FALSE, verify_callback_server, errstr);
if (rc != OK) return rc;
- verify_optional = FALSE;
+ server_verify_optional = FALSE;
}
else if (verify_check_host(&tls_try_verify_hosts) == OK)
{
- rc = setup_certs(ctx, tls_verify_certificates, tls_crl, NULL, TRUE);
+ rc = setup_certs(server_ctx, tls_verify_certificates, tls_crl, NULL,
+ TRUE, verify_callback_server, errstr);
if (rc != OK) return rc;
- verify_optional = TRUE;
+ server_verify_optional = TRUE;
}
/* Prepare for new connection */
-if ((ssl = SSL_new(ctx)) == NULL) return tls_error(US"SSL_new", NULL, NULL);
+if (!(server_ssl = SSL_new(server_ctx)))
+ return tls_error(US"SSL_new", NULL, NULL, errstr);
/* Warning: we used to SSL_clear(ssl) here, it was removed.
*
the response. Other smtp_printf() calls do not need it, because in non-TLS
mode, the fflush() happens when smtp_getc() is called. */
-SSL_set_session_id_context(ssl, sid_ctx, Ustrlen(sid_ctx));
-if (!tls_on_connect)
+SSL_set_session_id_context(server_ssl, sid_ctx, Ustrlen(sid_ctx));
+if (!tls_in.on_connect)
{
- smtp_printf("220 TLS go ahead\r\n");
+ smtp_printf("220 TLS go ahead\r\n", FALSE);
fflush(smtp_out);
}
/* Now negotiate the TLS session. We put our own timer on it, since it seems
that the OpenSSL library doesn't. */
-SSL_set_wfd(ssl, fileno(smtp_out));
-SSL_set_rfd(ssl, fileno(smtp_in));
-SSL_set_accept_state(ssl);
+SSL_set_wfd(server_ssl, fileno(smtp_out));
+SSL_set_rfd(server_ssl, fileno(smtp_in));
+SSL_set_accept_state(server_ssl);
DEBUG(D_tls) debug_printf("Calling SSL_accept\n");
sigalrm_seen = FALSE;
if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
-rc = SSL_accept(ssl);
+rc = SSL_accept(server_ssl);
alarm(0);
if (rc <= 0)
{
- tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL);
- if (ERR_get_error() == 0)
- log_write(0, LOG_MAIN,
- "TLS client disconnected cleanly (rejected our certificate?)");
+ (void) tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL, errstr);
return FAIL;
}
/* TLS has been set up. Adjust the input functions to read via TLS,
and initialize things. */
-construct_cipher_name(ssl);
+peer_cert(server_ssl, &tls_in, peerdn, sizeof(peerdn));
+
+construct_cipher_name(server_ssl, cipherbuf, sizeof(cipherbuf), &tls_in.bits);
+tls_in.cipher = cipherbuf;
DEBUG(D_tls)
{
uschar buf[2048];
- if (SSL_get_shared_ciphers(ssl, CS buf, sizeof(buf)) != NULL)
+ if (SSL_get_shared_ciphers(server_ssl, CS buf, sizeof(buf)) != NULL)
debug_printf("Shared ciphers: %s\n", buf);
}
+/* Record the certificate we presented */
+ {
+ X509 * crt = SSL_get_certificate(server_ssl);
+ tls_in.ourcert = crt ? X509_dup(crt) : NULL;
+ }
+/* Only used by the server-side tls (tls_in), including tls_getc.
+ Client-side (tls_out) reads (seem to?) go via
+ smtp_read_response()/ip_recv().
+ Hence no need to duplicate for _in and _out.
+ */
ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size);
ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0;
ssl_xfer_eof = ssl_xfer_error = 0;
receive_getc = tls_getc;
+receive_getbuf = tls_getbuf;
+receive_get_cache = tls_get_cache;
receive_ungetc = tls_ungetc;
receive_feof = tls_feof;
receive_ferror = tls_ferror;
receive_smtp_buffered = tls_smtp_buffered;
-tls_active = fileno(smtp_out);
+tls_in.active = fileno(smtp_out);
+return OK;
+}
+
+
+
+
+static int
+tls_client_basic_ctx_init(SSL_CTX * ctx,
+ host_item * host, smtp_transport_options_block * ob, tls_ext_ctx_cb * cbinfo,
+ uschar ** errstr)
+{
+int rc;
+/* stick to the old behaviour for compatibility if tls_verify_certificates is
+ set but both tls_verify_hosts and tls_try_verify_hosts is not set. Check only
+ the specified host patterns if one of them is defined */
+
+if ( ( !ob->tls_verify_hosts
+ && (!ob->tls_try_verify_hosts || !*ob->tls_try_verify_hosts)
+ )
+ || (verify_check_given_host(&ob->tls_verify_hosts, host) == OK)
+ )
+ client_verify_optional = FALSE;
+else if (verify_check_given_host(&ob->tls_try_verify_hosts, host) == OK)
+ client_verify_optional = TRUE;
+else
+ return OK;
+
+if ((rc = setup_certs(ctx, ob->tls_verify_certificates,
+ ob->tls_crl, host, client_verify_optional, verify_callback_client,
+ errstr)) != OK)
+ return rc;
+
+if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK)
+ {
+ cbinfo->verify_cert_hostnames =
+#ifdef SUPPORT_I18N
+ string_domain_utf8_to_alabel(host->name, NULL);
+#else
+ host->name;
+#endif
+ DEBUG(D_tls) debug_printf("Cert hostname to check: \"%s\"\n",
+ cbinfo->verify_cert_hostnames);
+ }
return OK;
}
+#ifdef EXPERIMENTAL_DANE
+static int
+dane_tlsa_load(SSL * ssl, host_item * host, dns_answer * dnsa, uschar ** errstr)
+{
+dns_record * rr;
+dns_scan dnss;
+const char * hostnames[2] = { CS host->name, NULL };
+int found = 0;
+
+if (DANESSL_init(ssl, NULL, hostnames) != 1)
+ return tls_error(US"hostnames load", host, NULL, errstr);
+
+for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
+ rr;
+ rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)
+ ) if (rr->type == T_TLSA)
+ {
+ const uschar * p = rr->data;
+ uint8_t usage, selector, mtype;
+ const char * mdname;
+
+ usage = *p++;
+
+ /* Only DANE-TA(2) and DANE-EE(3) are supported */
+ if (usage != 2 && usage != 3) continue;
+
+ selector = *p++;
+ mtype = *p++;
+
+ switch (mtype)
+ {
+ default: continue; /* Only match-types 0, 1, 2 are supported */
+ case 0: mdname = NULL; break;
+ case 1: mdname = "sha256"; break;
+ case 2: mdname = "sha512"; break;
+ }
+
+ found++;
+ switch (DANESSL_add_tlsa(ssl, usage, selector, mdname, p, rr->size - 3))
+ {
+ default:
+ return tls_error(US"tlsa load", host, NULL, errstr);
+ case 0: /* action not taken */
+ case 1: break;
+ }
+
+ tls_out.tlsa_usage |= 1<<usage;
+ }
+
+if (found)
+ return OK;
+
+log_write(0, LOG_MAIN, "DANE error: No usable TLSA records");
+return DEFER;
+}
+#endif /*EXPERIMENTAL_DANE*/
fd the fd of the connection
host connected host (for messages)
addr the first address
- dhparam DH parameter file
- certificate certificate file
- privatekey private key file
- sni TLS SNI to send to remote host
- verify_certs file for certificate verify
- crl file containing CRL
- require_ciphers list of allowed ciphers
- ------------------------------------------------------
- require_mac list of allowed MACs ) Not used
- require_kx list of allowed key_exchange methods ) for
- require_proto list of allowed protocols ) OpenSSL
- ------------------------------------------------------
- timeout startup timeout
+ tb transport (always smtp)
+ tlsa_dnsa tlsa lookup, if DANE, else null
+ errstr error string pointer
Returns: OK on success
FAIL otherwise - note that tls_error() will not give DEFER
*/
int
-tls_client_start(int fd, host_item *host, address_item *addr, uschar *dhparam,
- uschar *certificate, uschar *privatekey, uschar *sni,
- uschar *verify_certs, uschar *crl,
- uschar *require_ciphers, uschar *require_mac, uschar *require_kx,
- uschar *require_proto, int timeout)
+tls_client_start(int fd, host_item *host, address_item *addr,
+ transport_instance * tb,
+#ifdef EXPERIMENTAL_DANE
+ dns_answer * tlsa_dnsa,
+#endif
+ uschar ** errstr)
{
-static uschar txt[256];
-uschar *expciphers;
-X509* server_cert;
+smtp_transport_options_block * ob =
+ (smtp_transport_options_block *)tb->options_block;
+static uschar peerdn[256];
+uschar * expciphers;
int rc;
+static uschar cipherbuf[256];
+
+#ifndef DISABLE_OCSP
+BOOL request_ocsp = FALSE;
+BOOL require_ocsp = FALSE;
+#endif
+
+#ifdef EXPERIMENTAL_DANE
+tls_out.tlsa_usage = 0;
+#endif
+
+#ifndef DISABLE_OCSP
+ {
+# ifdef EXPERIMENTAL_DANE
+ if ( tlsa_dnsa
+ && ob->hosts_request_ocsp[0] == '*'
+ && ob->hosts_request_ocsp[1] == '\0'
+ )
+ {
+ /* Unchanged from default. Use a safer one under DANE */
+ request_ocsp = TRUE;
+ ob->hosts_request_ocsp = US"${if or { {= {0}{$tls_out_tlsa_usage}} "
+ " {= {4}{$tls_out_tlsa_usage}} } "
+ " {*}{}}";
+ }
+# endif
+
+ if ((require_ocsp =
+ verify_check_given_host(&ob->hosts_require_ocsp, host) == OK))
+ request_ocsp = TRUE;
+ else
+# ifdef EXPERIMENTAL_DANE
+ if (!request_ocsp)
+# endif
+ request_ocsp =
+ verify_check_given_host(&ob->hosts_request_ocsp, host) == OK;
+ }
+#endif
-rc = tls_init(host, dhparam, certificate, privatekey, addr);
+rc = tls_init(&client_ctx, host, NULL,
+ ob->tls_certificate, ob->tls_privatekey,
+#ifndef DISABLE_OCSP
+ (void *)(long)request_ocsp,
+#endif
+ addr, &client_static_cbinfo, errstr);
if (rc != OK) return rc;
-tls_certificate_verified = FALSE;
-verify_callback_called = FALSE;
+tls_out.certificate_verified = FALSE;
+client_verify_callback_called = FALSE;
-if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers))
+if (!expand_check(ob->tls_require_ciphers, US"tls_require_ciphers",
+ &expciphers, errstr))
return FAIL;
/* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they
are separated by underscores. So that I can use either form in my tests, and
also for general convenience, we turn underscores into hyphens here. */
-if (expciphers != NULL)
+if (expciphers)
{
uschar *s = expciphers;
- while (*s != 0) { if (*s == '_') *s = '-'; s++; }
+ while (*s) { if (*s == '_') *s = '-'; s++; }
DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers);
- if (!SSL_CTX_set_cipher_list(ctx, CS expciphers))
- return tls_error(US"SSL_CTX_set_cipher_list", host, NULL);
+ if (!SSL_CTX_set_cipher_list(client_ctx, CS expciphers))
+ return tls_error(US"SSL_CTX_set_cipher_list", host, NULL, errstr);
}
-rc = setup_certs(ctx, verify_certs, crl, host, FALSE);
-if (rc != OK) return rc;
+#ifdef EXPERIMENTAL_DANE
+if (tlsa_dnsa)
+ {
+ SSL_CTX_set_verify(client_ctx,
+ SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
+ verify_callback_client_dane);
+
+ if (!DANESSL_library_init())
+ return tls_error(US"library init", host, NULL, errstr);
+ if (DANESSL_CTX_init(client_ctx) <= 0)
+ return tls_error(US"context init", host, NULL, errstr);
+ }
+else
+
+#endif
+
+ if ((rc = tls_client_basic_ctx_init(client_ctx, host, ob,
+ client_static_cbinfo, errstr)) != OK)
+ return rc;
-if ((ssl = SSL_new(ctx)) == NULL) return tls_error(US"SSL_new", host, NULL);
-SSL_set_session_id_context(ssl, sid_ctx, Ustrlen(sid_ctx));
-SSL_set_fd(ssl, fd);
-SSL_set_connect_state(ssl);
+if ((client_ssl = SSL_new(client_ctx)) == NULL)
+ return tls_error(US"SSL_new", host, NULL, errstr);
+SSL_set_session_id_context(client_ssl, sid_ctx, Ustrlen(sid_ctx));
+SSL_set_fd(client_ssl, fd);
+SSL_set_connect_state(client_ssl);
-if (sni)
+if (ob->tls_sni)
{
- if (!expand_check(sni, US"tls_sni", &tls_sni))
+ if (!expand_check(ob->tls_sni, US"tls_sni", &tls_out.sni, errstr))
return FAIL;
- if (!Ustrlen(tls_sni))
- tls_sni = NULL;
+ if (!tls_out.sni)
+ {
+ DEBUG(D_tls) debug_printf("Setting TLS SNI forced to fail, not sending\n");
+ }
+ else if (!Ustrlen(tls_out.sni))
+ tls_out.sni = NULL;
else
{
- DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tls_sni);
- SSL_set_tlsext_host_name(ssl, tls_sni);
+#ifdef EXIM_HAVE_OPENSSL_TLSEXT
+ DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tls_out.sni);
+ SSL_set_tlsext_host_name(client_ssl, tls_out.sni);
+#else
+ log_write(0, LOG_MAIN, "SNI unusable with this OpenSSL library version; ignoring \"%s\"\n",
+ tls_out.sni);
+#endif
+ }
+ }
+
+#ifdef EXPERIMENTAL_DANE
+if (tlsa_dnsa)
+ if ((rc = dane_tlsa_load(client_ssl, host, tlsa_dnsa, errstr)) != OK)
+ return rc;
+#endif
+
+#ifndef DISABLE_OCSP
+/* Request certificate status at connection-time. If the server
+does OCSP stapling we will get the callback (set in tls_init()) */
+# ifdef EXPERIMENTAL_DANE
+if (request_ocsp)
+ {
+ const uschar * s;
+ if ( ((s = ob->hosts_require_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage"))
+ || ((s = ob->hosts_request_ocsp) && Ustrstr(s, US"tls_out_tlsa_usage"))
+ )
+ { /* Re-eval now $tls_out_tlsa_usage is populated. If
+ this means we avoid the OCSP request, we wasted the setup
+ cost in tls_init(). */
+ require_ocsp = verify_check_given_host(&ob->hosts_require_ocsp, host) == OK;
+ request_ocsp = require_ocsp
+ || verify_check_given_host(&ob->hosts_request_ocsp, host) == OK;
}
}
+# endif
+
+if (request_ocsp)
+ {
+ SSL_set_tlsext_status_type(client_ssl, TLSEXT_STATUSTYPE_ocsp);
+ client_static_cbinfo->u_ocsp.client.verify_required = require_ocsp;
+ tls_out.ocsp = OCSP_NOT_RESP;
+ }
+#endif
+
+#ifndef DISABLE_EVENT
+client_static_cbinfo->event_action = tb->event_action;
+#endif
/* There doesn't seem to be a built-in timeout on connection. */
DEBUG(D_tls) debug_printf("Calling SSL_connect\n");
sigalrm_seen = FALSE;
-alarm(timeout);
-rc = SSL_connect(ssl);
+alarm(ob->command_timeout);
+rc = SSL_connect(client_ssl);
alarm(0);
+#ifdef EXPERIMENTAL_DANE
+if (tlsa_dnsa)
+ DANESSL_cleanup(client_ssl);
+#endif
+
if (rc <= 0)
- return tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL);
+ return tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL,
+ errstr);
DEBUG(D_tls) debug_printf("SSL_connect succeeded\n");
-/* Beware anonymous ciphers which lead to server_cert being NULL */
-server_cert = SSL_get_peer_certificate (ssl);
-if (server_cert)
+peer_cert(client_ssl, &tls_out, peerdn, sizeof(peerdn));
+
+construct_cipher_name(client_ssl, cipherbuf, sizeof(cipherbuf), &tls_out.bits);
+tls_out.cipher = cipherbuf;
+
+/* Record the certificate we presented */
{
- tls_peerdn = US X509_NAME_oneline(X509_get_subject_name(server_cert),
- CS txt, sizeof(txt));
- tls_peerdn = txt;
+ X509 * crt = SSL_get_certificate(client_ssl);
+ tls_out.ourcert = crt ? X509_dup(crt) : NULL;
}
-else
- tls_peerdn = NULL;
-construct_cipher_name(ssl); /* Sets tls_cipher */
-
-tls_active = fd;
+tls_out.active = fd;
return OK;
}
+static BOOL
+tls_refill(unsigned lim)
+{
+int error;
+int inbytes;
+
+DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", server_ssl,
+ ssl_xfer_buffer, ssl_xfer_buffer_size);
+
+if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
+inbytes = SSL_read(server_ssl, CS ssl_xfer_buffer,
+ MIN(ssl_xfer_buffer_size, lim));
+error = SSL_get_error(server_ssl, inbytes);
+alarm(0);
+
+/* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been
+closed down, not that the socket itself has been closed down. Revert to
+non-SSL handling. */
+
+if (error == SSL_ERROR_ZERO_RETURN)
+ {
+ DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n");
+
+ receive_getc = smtp_getc;
+ receive_getbuf = smtp_getbuf;
+ receive_get_cache = smtp_get_cache;
+ receive_ungetc = smtp_ungetc;
+ receive_feof = smtp_feof;
+ receive_ferror = smtp_ferror;
+ receive_smtp_buffered = smtp_buffered;
+
+ SSL_free(server_ssl);
+ server_ssl = NULL;
+ tls_in.active = -1;
+ tls_in.bits = 0;
+ tls_in.cipher = NULL;
+ tls_in.peerdn = NULL;
+ tls_in.sni = NULL;
+
+ return FALSE;
+ }
+
+/* Handle genuine errors */
+
+else if (error == SSL_ERROR_SSL)
+ {
+ ERR_error_string(ERR_get_error(), ssl_errstring);
+ log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring);
+ ssl_xfer_error = 1;
+ return FALSE;
+ }
+
+else if (error != SSL_ERROR_NONE)
+ {
+ DEBUG(D_tls) debug_printf("Got SSL error %d\n", error);
+ ssl_xfer_error = 1;
+ return FALSE;
+ }
+
+#ifndef DISABLE_DKIM
+dkim_exim_verify_feed(ssl_xfer_buffer, inbytes);
+#endif
+ssl_xfer_buffer_hwm = inbytes;
+ssl_xfer_buffer_lwm = 0;
+return TRUE;
+}
+
+
/*************************************************
* TLS version of getc *
*************************************************/
/* This gets the next byte from the TLS input buffer. If the buffer is empty,
it refills the buffer via the SSL reading function.
-Arguments: none
+Arguments: lim Maximum amount to read/buffer
Returns: the next character or EOF
+
+Only used by the server-side TLS.
*/
int
-tls_getc(void)
+tls_getc(unsigned lim)
{
if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm)
- {
- int error;
- int inbytes;
+ if (!tls_refill(lim))
+ return ssl_xfer_error ? EOF : smtp_getc(lim);
- DEBUG(D_tls) debug_printf("Calling SSL_read(%p, %p, %u)\n", ssl,
- ssl_xfer_buffer, ssl_xfer_buffer_size);
+/* Something in the buffer; return next uschar */
- if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
- inbytes = SSL_read(ssl, CS ssl_xfer_buffer, ssl_xfer_buffer_size);
- error = SSL_get_error(ssl, inbytes);
- alarm(0);
+return ssl_xfer_buffer[ssl_xfer_buffer_lwm++];
+}
- /* SSL_ERROR_ZERO_RETURN appears to mean that the SSL session has been
- closed down, not that the socket itself has been closed down. Revert to
- non-SSL handling. */
+uschar *
+tls_getbuf(unsigned * len)
+{
+unsigned size;
+uschar * buf;
- if (error == SSL_ERROR_ZERO_RETURN)
+if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm)
+ if (!tls_refill(*len))
{
- DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n");
-
- receive_getc = smtp_getc;
- receive_ungetc = smtp_ungetc;
- receive_feof = smtp_feof;
- receive_ferror = smtp_ferror;
- receive_smtp_buffered = smtp_buffered;
-
- SSL_free(ssl);
- ssl = NULL;
- tls_active = -1;
- tls_bits = 0;
- tls_cipher = NULL;
- tls_peerdn = NULL;
- tls_sni = NULL;
-
- return smtp_getc();
+ if (!ssl_xfer_error) return smtp_getbuf(len);
+ *len = 0;
+ return NULL;
}
- /* Handle genuine errors */
-
- else if (error == SSL_ERROR_SSL)
- {
- ERR_error_string(ERR_get_error(), ssl_errstring);
- log_write(0, LOG_MAIN, "TLS error (SSL_read): %s", ssl_errstring);
- ssl_xfer_error = 1;
- return EOF;
- }
+if ((size = ssl_xfer_buffer_hwm - ssl_xfer_buffer_lwm) > *len)
+ size = *len;
+buf = &ssl_xfer_buffer[ssl_xfer_buffer_lwm];
+ssl_xfer_buffer_lwm += size;
+*len = size;
+return buf;
+}
- else if (error != SSL_ERROR_NONE)
- {
- DEBUG(D_tls) debug_printf("Got SSL error %d\n", error);
- ssl_xfer_error = 1;
- return EOF;
- }
+void
+tls_get_cache()
+{
#ifndef DISABLE_DKIM
- dkim_exim_verify_feed(ssl_xfer_buffer, inbytes);
+int n = ssl_xfer_buffer_hwm - ssl_xfer_buffer_lwm;
+if (n > 0)
+ dkim_exim_verify_feed(ssl_xfer_buffer+ssl_xfer_buffer_lwm, n);
#endif
- ssl_xfer_buffer_hwm = inbytes;
- ssl_xfer_buffer_lwm = 0;
- }
+}
-/* Something in the buffer; return next uschar */
-return ssl_xfer_buffer[ssl_xfer_buffer_lwm++];
+BOOL
+tls_could_read(void)
+{
+return ssl_xfer_buffer_lwm < ssl_xfer_buffer_hwm || SSL_pending(server_ssl) > 0;
}
-
/*************************************************
* Read bytes from TLS channel *
*************************************************/
Returns: the number of bytes read
-1 after a failed read
+
+Only used by the client-side TLS.
*/
int
-tls_read(uschar *buff, size_t len)
+tls_read(BOOL is_server, uschar *buff, size_t len)
{
+SSL *ssl = is_server ? server_ssl : client_ssl;
int inbytes;
int error;
return -1;
}
else if (error != SSL_ERROR_NONE)
- {
return -1;
- }
return inbytes;
}
/*
Arguments:
+ is_server channel specifier
buff buffer of data
len number of bytes
+ more further data expected soon
Returns: the number of bytes after a successful write,
-1 after a failed write
+
+Used by both server-side and client-side TLS.
*/
int
-tls_write(const uschar *buff, size_t len)
+tls_write(BOOL is_server, const uschar *buff, size_t len, BOOL more)
{
-int outbytes;
-int error;
-int left = len;
+int outbytes, error, left;
+SSL *ssl = is_server ? server_ssl : client_ssl;
+static gstring * corked = NULL;
+
+DEBUG(D_tls) debug_printf("%s(%p, %lu%s)\n", __FUNCTION__,
+ buff, (unsigned long)len, more ? ", more" : "");
+
+/* Lacking a CORK or MSG_MORE facility (such as GnuTLS has) we copy data when
+"more" is notified. This hack is only ok if small amounts are involved AND only
+one stream does it, in one context (i.e. no store reset). Currently it is used
+for the responses to the received SMTP MAIL , RCPT, DATA sequence, only. */
+
+if (is_server && (more || corked))
+ {
+ corked = string_catn(corked, buff, len);
+ if (more)
+ return len;
+ buff = CUS corked->s;
+ len = corked->ptr;
+ corked = NULL;
+ }
-DEBUG(D_tls) debug_printf("tls_do_write(%p, %d)\n", buff, left);
-while (left > 0)
+for (left = len; left > 0;)
{
DEBUG(D_tls) debug_printf("SSL_write(SSL, %p, %d)\n", buff, left);
outbytes = SSL_write(ssl, CS buff, left);
switch (error)
{
case SSL_ERROR_SSL:
- ERR_error_string(ERR_get_error(), ssl_errstring);
- log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring);
- return -1;
+ ERR_error_string(ERR_get_error(), ssl_errstring);
+ log_write(0, LOG_MAIN, "TLS error (SSL_write): %s", ssl_errstring);
+ return -1;
case SSL_ERROR_NONE:
- left -= outbytes;
- buff += outbytes;
- break;
+ left -= outbytes;
+ buff += outbytes;
+ break;
case SSL_ERROR_ZERO_RETURN:
- log_write(0, LOG_MAIN, "SSL channel closed on write");
- return -1;
+ log_write(0, LOG_MAIN, "SSL channel closed on write");
+ return -1;
+
+ case SSL_ERROR_SYSCALL:
+ log_write(0, LOG_MAIN, "SSL_write: (from %s) syscall: %s",
+ sender_fullhost ? sender_fullhost : US"<unknown>",
+ strerror(errno));
+ return -1;
default:
- log_write(0, LOG_MAIN, "SSL_write error %d", error);
- return -1;
+ log_write(0, LOG_MAIN, "SSL_write error %d", error);
+ return -1;
}
}
return len;
Arguments: TRUE if SSL_shutdown is to be called
Returns: nothing
+
+Used by both server-side and client-side TLS.
*/
void
-tls_close(BOOL shutdown)
+tls_close(BOOL is_server, BOOL shutdown)
{
-if (tls_active < 0) return; /* TLS was not active */
+SSL **sslp = is_server ? &server_ssl : &client_ssl;
+int *fdp = is_server ? &tls_in.active : &tls_out.active;
+
+if (*fdp < 0) return; /* TLS was not active */
if (shutdown)
{
DEBUG(D_tls) debug_printf("tls_close(): shutting down SSL\n");
- SSL_shutdown(ssl);
+ SSL_shutdown(*sslp);
+ }
+
+SSL_free(*sslp);
+*sslp = NULL;
+
+*fdp = -1;
+}
+
+
+
+
+/*************************************************
+* Let tls_require_ciphers be checked at startup *
+*************************************************/
+
+/* The tls_require_ciphers option, if set, must be something which the
+library can parse.
+
+Returns: NULL on success, or error message
+*/
+
+uschar *
+tls_validate_require_cipher(void)
+{
+SSL_CTX *ctx;
+uschar *s, *expciphers, *err;
+
+/* this duplicates from tls_init(), we need a better "init just global
+state, for no specific purpose" singleton function of our own */
+
+SSL_load_error_strings();
+OpenSSL_add_ssl_algorithms();
+#if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256)
+/* SHA256 is becoming ever more popular. This makes sure it gets added to the
+list of available digests. */
+EVP_add_digest(EVP_sha256());
+#endif
+
+if (!(tls_require_ciphers && *tls_require_ciphers))
+ return NULL;
+
+if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers,
+ &err))
+ return US"failed to expand tls_require_ciphers";
+
+if (!(expciphers && *expciphers))
+ return NULL;
+
+/* normalisation ripped from above */
+s = expciphers;
+while (*s != 0) { if (*s == '_') *s = '-'; s++; }
+
+err = NULL;
+
+ctx = SSL_CTX_new(SSLv23_server_method());
+if (!ctx)
+ {
+ ERR_error_string(ERR_get_error(), ssl_errstring);
+ return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring);
+ }
+
+DEBUG(D_tls)
+ debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers);
+
+if (!SSL_CTX_set_cipher_list(ctx, CS expciphers))
+ {
+ ERR_error_string(ERR_get_error(), ssl_errstring);
+ err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed: %s",
+ expciphers, ssl_errstring);
}
-SSL_free(ssl);
-ssl = NULL;
+SSL_CTX_free(ctx);
-tls_active = -1;
+return err;
}
it can result in serious failures, including crashing with a SIGSEGV. So
report the version found by the compiler and the run-time version.
+Note: some OS vendors backport security fixes without changing the version
+number/string, and the version date remains unchanged. The _build_ date
+will change, so we can more usefully assist with version diagnosis by also
+reporting the build date.
+
Arguments: a FILE* to print the results to
Returns: nothing
*/
tls_version_report(FILE *f)
{
fprintf(f, "Library version: OpenSSL: Compile: %s\n"
- " Runtime: %s\n",
+ " Runtime: %s\n"
+ " : %s\n",
OPENSSL_VERSION_TEXT,
- SSLeay_version(SSLEAY_VERSION));
+ SSLeay_version(SSLEAY_VERSION),
+ SSLeay_version(SSLEAY_BUILT_ON));
+/* third line is 38 characters for the %s and the line is 73 chars long;
+the OpenSSL output includes a "built on: " prefix already. */
}
/*************************************************
-* Pseudo-random number generation *
+* Random number generation *
*************************************************/
/* Pseudo-random number generation. The result is not expected to be
*/
int
-pseudo_random_number(int max)
+vaguely_random_number(int max)
{
unsigned int r;
int i, needed_len;
+static pid_t pidlast = 0;
+pid_t pidnow;
uschar *p;
uschar smallbuf[sizeof(r)];
if (max <= 1)
return 0;
+pidnow = getpid();
+if (pidnow != pidlast)
+ {
+ /* Although OpenSSL documents that "OpenSSL makes sure that the PRNG state
+ is unique for each thread", this doesn't apparently apply across processes,
+ so our own warning from vaguely_random_number_fallback() applies here too.
+ Fix per PostgreSQL. */
+ if (pidlast != 0)
+ RAND_cleanup();
+ pidlast = pidnow;
+ }
+
/* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */
if (!RAND_status())
{
gettimeofday(&r.tv, NULL);
r.p = getpid();
- RAND_seed((uschar *)(&r), sizeof(r));
+ RAND_seed(US (&r), sizeof(r));
}
/* We're after pseudo-random, not random; if we still don't have enough data
in the internal PRNG then our options are limited. We could sleep and hope
if (i < needed_len)
needed_len = i;
+#ifdef EXIM_HAVE_RAND_PSEUDO
/* We do not care if crypto-strong */
-(void) RAND_pseudo_bytes(smallbuf, needed_len);
+i = RAND_pseudo_bytes(smallbuf, needed_len);
+#else
+i = RAND_bytes(smallbuf, needed_len);
+#endif
+
+if (i < 0)
+ {
+ DEBUG(D_all)
+ debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n");
+ return vaguely_random_number_fallback(max);
+ }
+
r = 0;
for (p = smallbuf; needed_len; --needed_len, ++p)
{
to apply.
This list is current as of:
- ==> 1.0.1b <== */
+ ==> 1.0.1b <==
+Plus SSL_OP_SAFARI_ECDHE_ECDSA_BUG from 2013-June patch/discussion on openssl-dev
+*/
static struct exim_openssl_option exim_openssl_options[] = {
/* KEEP SORTED ALPHABETICALLY! */
#ifdef SSL_OP_ALL
#ifdef SSL_OP_NO_TLSv1_2
{ US"no_tlsv1_2", SSL_OP_NO_TLSv1_2 },
#endif
+#ifdef SSL_OP_SAFARI_ECDHE_ECDSA_BUG
+ { US"safari_ecdhe_ecdsa_bug", SSL_OP_SAFARI_ECDHE_ECDSA_BUG },
+#endif
#ifdef SSL_OP_SINGLE_DH_USE
{ US"single_dh_use", SSL_OP_SINGLE_DH_USE },
#endif
uschar keep_c;
BOOL adding, item_parsed;
-result = 0L;
-/* Prior to 4.78 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed
+result = SSL_OP_NO_TICKET;
+/* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed
* from default because it increases BEAST susceptibility. */
+#ifdef SSL_OP_NO_SSLv2
+result |= SSL_OP_NO_SSLv2;
+#endif
+#ifdef SSL_OP_SINGLE_DH_USE
+result |= SSL_OP_SINGLE_DH_USE;
+#endif
-if (option_spec == NULL)
+if (!option_spec)
{
*results = result;
return TRUE;
keep_c = *end;
*end = '\0';
item_parsed = tls_openssl_one_option_parse(s, &item);
+ *end = keep_c;
if (!item_parsed)
{
DEBUG(D_tls) debug_printf("openssl option setting unrecognised: \"%s\"\n", s);
result |= item;
else
result &= ~item;
- *end = keep_c;
s = end;
}
return TRUE;
}
+/* vi: aw ai sw=2
+*/
/* End of tls-openssl.c */
git://git.exim.org / exim.git / blobdiff