-/* $Cambridge: exim/src/src/tls-gnu.c,v 1.18 2007/01/18 15:35:42 ph10 Exp $ */
-
/*************************************************
* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2007 */
+/* Copyright (c) University of Cambridge 1995 - 2009 */
/* See the file NOTICE for conditions of use and distribution. */
/* This module provides TLS (aka SSL) support for Exim using the GnuTLS
No cryptographic code is included in Exim. All this module does is to call
functions from the GnuTLS library. */
+/* Note: This appears to be using an old API from compat.h; it is likely that
+someone familiary with GnuTLS programming could rework a lot of this to a
+modern API and perhaps remove the explicit knowledge of crypto algorithms from
+Exim. Such a re-work would be most welcome and we'd sacrifice support for
+older GnuTLS releases without too many qualms -- maturity and experience
+in crypto libraries tends to improve their robustness against attack.
+Frankly, if you maintain it, you decide what's supported and what isn't. */
/* Heading stuff for GnuTLS */
#define PARAM_SIZE 2*1024
-/* Values for verify_requirment and initialized */
+/* Values for verify_requirment */
enum { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED };
-enum { INITIALIZED_NOT, INITIALIZED_SERVER, INITIALIZED_CLIENT };
/* Local static variables for GNUTLS */
-static BOOL initialized = INITIALIZED_NOT;
static host_item *client_host;
static gnutls_dh_params dh_params = NULL;
and space into which it can be copied and altered. */
static const int default_proto_priority[16] = {
+ /* These are gnutls_protocol_t enum values */
+#if GNUTLS_VERSION_MAJOR > 1 || GNUTLS_VERSION_MINOR >= 7
+ GNUTLS_TLS1_2,
+#endif
+#if GNUTLS_VERSION_MAJOR > 1 || GNUTLS_VERSION_MINOR >= 2
+ GNUTLS_TLS1_1,
+#endif
GNUTLS_TLS1,
GNUTLS_SSL3,
0 };
} pri_item;
-static int tls1_codes[] = { GNUTLS_TLS1, 0 };
+#if GNUTLS_VERSION_MAJOR > 1 || GNUTLS_VERSION_MINOR >= 7
+static int tls1_2_codes[] = { GNUTLS_TLS1_2, 0 };
+#endif
+#if GNUTLS_VERSION_MAJOR > 1 || GNUTLS_VERSION_MINOR >= 2
+static int tls1_1_codes[] = { GNUTLS_TLS1_1, 0 };
+#endif
+/* more recent libraries define this as an equivalent value to the
+canonical GNUTLS_TLS1_0; since they're the same, we stick to the
+older name. */
+static int tls1_0_codes[] = { GNUTLS_TLS1, 0 };
static int ssl3_codes[] = { GNUTLS_SSL3, 0 };
static pri_item proto_index[] = {
- { US"TLS1", tls1_codes },
+#if GNUTLS_VERSION_MAJOR > 1 || GNUTLS_VERSION_MINOR >= 7
+ { US"TLS1.2", tls1_2_codes },
+#endif
+#if GNUTLS_VERSION_MAJOR > 1 || GNUTLS_VERSION_MINOR >= 2
+ { US"TLS1.1", tls1_1_codes },
+#endif
+ { US"TLS1.0", tls1_0_codes },
+ { US"TLS1", tls1_0_codes },
{ US"SSL3", ssl3_codes }
};
prefix text to include in the logged error
host NULL if setting up a server;
the connected host if setting up a client
- err a GnuTLS error number, or 0 if local error
+ msg additional error string (may be NULL)
+ usually obtained from gnutls_strerror()
Returns: OK/DEFER/FAIL
*/
static int
-tls_error(uschar *prefix, host_item *host, int err)
+tls_error(uschar *prefix, host_item *host, const char *msg)
{
-uschar *errtext = US"";
-if (err != 0) errtext = string_sprintf(": %s", gnutls_strerror(err));
if (host == NULL)
{
- log_write(0, LOG_MAIN, "TLS error on connection from %s (%s)%s",
- (sender_fullhost != NULL)? sender_fullhost : US "local process",
- prefix, errtext);
+ uschar *conn_info = smtp_get_connection_info();
+ if (strncmp(conn_info, "SMTP ", 5) == 0)
+ conn_info += 5;
+ log_write(0, LOG_MAIN, "TLS error on %s (%s)%s%s",
+ conn_info, prefix, msg ? ": " : "", msg ? msg : "");
return DEFER;
}
else
{
- log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s)%s",
- host->name, host->address, prefix, errtext);
+ log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s)%s%s",
+ host->name, host->address, prefix, msg ? ": " : "", msg ? msg : "");
return FAIL;
}
}
*/
static BOOL
-verify_certificate(gnutls_session session, uschar **error)
+verify_certificate(gnutls_session session, const char **error)
{
-int verify;
+int rc = -1;
uschar *dn_string = US"";
const gnutls_datum *cert;
-unsigned int cert_size = 0;
+unsigned int verify, cert_size = 0;
*error = NULL;
dn_string = string_copy_malloc(buff);
}
- verify = gnutls_certificate_verify_peers(session);
+ rc = gnutls_certificate_verify_peers2(session, &verify);
}
else
{
DEBUG(D_tls) debug_printf("no peer certificate supplied\n");
verify = GNUTLS_CERT_INVALID;
- *error = US"not supplied";
+ *error = "not supplied";
}
/* Handle the result of verification. INVALID seems to be set as well
as REVOKED, but leave the test for both. */
-if ((verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) != 0)
+if ((rc < 0) || (verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) != 0)
{
tls_certificate_verified = FALSE;
if (*error == NULL) *error = ((verify & GNUTLS_CERT_REVOKED) != 0)?
- US"revoked" : US"invalid";
+ "revoked" : "invalid";
if (verify_requirement == VERIFY_REQUIRED)
{
DEBUG(D_tls) debug_printf("TLS certificate verification failed (%s): "
/* Initialize the data structures for holding the parameters */
ret = gnutls_dh_params_init(&dh_params);
-if (ret < 0) return tls_error(US"init dh_params", host, ret);
+if (ret < 0) return tls_error(US"init dh_params", host, gnutls_strerror(ret));
/* Set up the name of the cache file */
if (!string_format(filename, sizeof(filename), "%s/gnutls-params",
spool_directory))
- return tls_error(US"overlong filename", host, 0);
+ return tls_error(US"overlong filename", host, NULL);
/* Open the cache file for reading and if successful, read it and set up the
parameters. */
if (fstat(fd, &statbuf) < 0)
{
(void)close(fd);
- return tls_error(US"TLS cache stat failed", host, 0);
+ return tls_error(US"TLS cache stat failed", host, strerror(errno));
}
m.size = statbuf.st_size;
m.data = malloc(m.size);
if (m.data == NULL)
- return tls_error(US"memory allocation failed", host, 0);
+ return tls_error(US"memory allocation failed", host, strerror(errno));
+ errno = 0;
if (read(fd, m.data, m.size) != m.size)
- return tls_error(US"TLS cache read failed", host, 0);
+ return tls_error(US"TLS cache read failed", host, strerror(errno));
(void)close(fd);
ret = gnutls_dh_params_import_pkcs3(dh_params, &m, GNUTLS_X509_FMT_PEM);
- if (ret < 0) return tls_error(US"DH params import", host, ret);
+ if (ret < 0)
+ return tls_error(US"DH params import", host, gnutls_strerror(ret));
DEBUG(D_tls) debug_printf("read D-H parameters from file\n");
free(m.data);
}
else
return tls_error(string_open_failed(errno, "%s for reading", filename),
- host, 0);
+ host, NULL);
/* If ret < 0, either the cache file does not exist, or the data it contains
is not useful. One particular case of this is when upgrading from an older
DEBUG(D_tls) debug_printf("generating %d bit Diffie-Hellman key...\n",
DH_BITS);
ret = gnutls_dh_params_generate2(dh_params, DH_BITS);
- if (ret < 0) return tls_error(US"D-H key generation", host, ret);
+ if (ret < 0) return tls_error(US"D-H key generation", host, gnutls_strerror(ret));
/* Write the parameters to a file in the spool directory so that we
can use them from other Exim processes. */
fd = Uopen(tempfilename, O_WRONLY|O_CREAT, 0400);
if (fd < 0)
return tls_error(string_open_failed(errno, "%s for writing", filename),
- host, 0);
+ host, NULL);
(void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */
/* export the parameters in a format that can be generated using GNUTLS'
m.size = PARAM_SIZE;
m.data = malloc(m.size);
if (m.data == NULL)
- return tls_error(US"memory allocation failed", host, 0);
+ return tls_error(US"memory allocation failed", host, strerror(errno));
m.size = PARAM_SIZE;
ret = gnutls_dh_params_export_pkcs3(dh_params, GNUTLS_X509_FMT_PEM, m.data,
&m.size);
- if (ret < 0) return tls_error(US"DH params export", host, ret);
+ if (ret < 0)
+ return tls_error(US"DH params export", host, gnutls_strerror(ret));
m.size = Ustrlen(m.data);
+ errno = 0;
if (write(fd, m.data, m.size) != m.size || write(fd, "\n", 1) != 1)
- return tls_error(US"TLS cache write failed", host, 0);
+ return tls_error(US"TLS cache write failed", host, strerror(errno));
free(m.data);
(void)close(fd);
if (rename(CS tempfilename, CS filename) < 0)
- return tls_error(string_sprintf("failed to rename %s as %s: %s",
- tempfilename, filename, strerror(errno)), host, 0);
+ return tls_error(string_sprintf("failed to rename %s as %s",
+ tempfilename, filename), host, strerror(errno));
DEBUG(D_tls) debug_printf("wrote D-H parameters to file %s\n", filename);
}
int rc;
uschar *cert_expanded, *key_expanded, *cas_expanded, *crl_expanded;
-initialized = (host == NULL)? INITIALIZED_SERVER : INITIALIZED_CLIENT;
+client_host = host;
rc = gnutls_global_init();
-if (rc < 0) return tls_error(US"tls-init", host, rc);
+if (rc < 0) return tls_error(US"tls-init", host, gnutls_strerror(rc));
/* Create D-H parameters, or read them from the cache file. This function does
its own SMTP error messaging. */
/* Create the credentials structure */
rc = gnutls_certificate_allocate_credentials(&x509_cred);
-if (rc < 0) return tls_error(US"certificate_allocate_credentials", host, rc);
+if (rc < 0)
+ return tls_error(US"certificate_allocate_credentials",
+ host, gnutls_strerror(rc));
/* This stuff must be done for each session, because different certificates
may be required for different sessions. */
{
uschar *msg = string_sprintf("cert/key setup: cert=%s key=%s",
cert_expanded, key_expanded);
- return tls_error(msg, host, rc);
+ return tls_error(msg, host, gnutls_strerror(rc));
}
}
else
{
if (host == NULL)
- return tls_error(US"no TLS server certificate is specified", host, 0);
+ return tls_error(US"no TLS server certificate is specified", NULL, NULL);
DEBUG(D_tls) debug_printf("no TLS client certificate is specified\n");
}
{
rc = gnutls_certificate_set_x509_trust_file(x509_cred, CS cas_expanded,
GNUTLS_X509_FMT_PEM);
- if (rc < 0) return tls_error(US"setup_certs", host, rc);
+ if (rc < 0) return tls_error(US"setup_certs", host, gnutls_strerror(rc));
if (crl != NULL && *crl != 0)
{
DEBUG(D_tls) debug_printf("loading CRL file = %s\n", crl_expanded);
rc = gnutls_certificate_set_x509_crl_file(x509_cred, CS crl_expanded,
GNUTLS_X509_FMT_PEM);
- if (rc < 0) return tls_error(US"CRL setup", host, rc);
+ if (rc < 0) return tls_error(US"CRL setup", host, gnutls_strerror(rc));
}
}
}
gnutls_db_set_cache_expiration(session, ssl_session_timeout);
+/* Reduce security in favour of increased compatibility, if the admin
+decides to make that trade-off. */
+if (gnutls_compat_mode)
+ {
+#if LIBGNUTLS_VERSION_NUMBER >= 0x020104
+ DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n");
+ gnutls_session_enable_compatibility_mode(session);
+#else
+ DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n");
+#endif
+ }
+
DEBUG(D_tls) debug_printf("initialized GnuTLS session\n");
return session;
}
{
static uschar cipherbuf[256];
uschar *ver;
-int bits, c, kx, mac;
+int bits, c, kx, mac, rc;
+#ifdef GNUTLS_CB_TLS_UNIQUE
+gnutls_datum_t channel;
+#endif
ver = string_copy(
US gnutls_protocol_get_name(gnutls_protocol_get_version(session)));
tls_cipher = cipherbuf;
DEBUG(D_tls) debug_printf("cipher: %s\n", cipherbuf);
+
+if (tls_channelbinding_b64)
+ free(tls_channelbinding_b64);
+tls_channelbinding_b64 = NULL;
+
+#ifdef GNUTLS_CB_TLS_UNIQUE
+channel = { NULL, 0 };
+rc = gnutls_session_channel_binding(session, GNUTLS_CB_TLS_UNIQUE, &channel);
+if (rc) {
+ DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc));
+} else {
+ tls_channelbinding_b64 = auth_b64encode(channel.data, (int)channel.size);
+ DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n");
+}
+#endif
}
uschar *require_kx, uschar *require_proto)
{
int rc;
-uschar *error;
+const char *error;
uschar *expciphers = NULL;
uschar *expmac = NULL;
uschar *expkx = NULL;
if (tls_active >= 0)
{
- log_write(0, LOG_MAIN, "STARTTLS received in already encrypted "
- "connection from %s",
- (sender_fullhost != NULL)? sender_fullhost : US"local process");
+ tls_error("STARTTLS received after TLS started", NULL, "");
smtp_printf("554 Already in TLS\r\n");
return FAIL;
}
tls_session = tls_session_init(GNUTLS_SERVER, expciphers, expmac, expkx,
expproto);
if (tls_session == NULL)
- return tls_error(US"tls_session_init", NULL, GNUTLS_E_MEMORY_ERROR);
+ return tls_error(US"tls_session_init", NULL,
+ gnutls_strerror(GNUTLS_E_MEMORY_ERROR));
/* Set context and tell client to go ahead, except in the case of TLS startup
on connection, where outputting anything now upsets the clients and tends to
if (rc < 0)
{
- if (sigalrm_seen)
- Ustrcpy(ssl_errstring, "timed out");
- else
- Ustrcpy(ssl_errstring, gnutls_strerror(rc));
- log_write(0, LOG_MAIN,
- "TLS error on connection from %s (gnutls_handshake): %s",
- (sender_fullhost != NULL)? sender_fullhost : US"local process",
- ssl_errstring);
+ tls_error(US"gnutls_handshake", NULL,
+ sigalrm_seen ? "timed out" : gnutls_strerror(rc));
/* It seems that, except in the case of a timeout, we have to close the
connection right here; otherwise if the other end is running OpenSSL it hangs
if (verify_requirement != VERIFY_NONE &&
!verify_certificate(tls_session, &error))
{
- log_write(0, LOG_MAIN,
- "TLS error on connection from %s: certificate verification failed (%s)",
- (sender_fullhost != NULL)? sender_fullhost : US"local process", error);
+ tls_error(US"certificate verification failed", NULL, error);
return FAIL;
}
receive_ungetc = tls_ungetc;
receive_feof = tls_feof;
receive_ferror = tls_ferror;
+receive_smtp_buffered = tls_smtp_buffered;
tls_active = fileno(smtp_out);
uschar *expmac = NULL;
uschar *expkx = NULL;
uschar *expproto = NULL;
-uschar *error;
+const char *error;
unsigned int server_certs_size;
int rc;
DEBUG(D_tls) debug_printf("initializing GnuTLS as a client\n");
-client_host = host;
verify_requirement = (verify_certs == NULL)? VERIFY_NONE : VERIFY_REQUIRED;
rc = tls_init(host, certificate, privatekey, verify_certs, verify_crl);
if (rc != OK) return rc;
expproto);
if (tls_session == NULL)
- return tls_error(US "tls_session_init", host, GNUTLS_E_MEMORY_ERROR);
+ return tls_error(US "tls_session_init", host,
+ gnutls_strerror(GNUTLS_E_MEMORY_ERROR));
gnutls_transport_set_ptr(tls_session, (gnutls_transport_ptr)fd);
alarm(0);
if (rc < 0)
- {
- if (sigalrm_seen)
- {
- log_write(0, LOG_MAIN, "TLS error on connection to %s [%s]: "
- "gnutls_handshake timed out", host->name, host->address);
- return FAIL;
- }
- else return tls_error(US "gnutls_handshake", host, rc);
- }
+ return tls_error(US "gnutls_handshake", host,
+ sigalrm_seen ? "timed out" : gnutls_strerror(rc));
server_certs = gnutls_certificate_get_peers(tls_session, &server_certs_size);
if (verify_requirement != VERIFY_NONE &&
!verify_certificate(tls_session, &error))
- {
- log_write(0, LOG_MAIN,
- "TLS error on connection to %s [%s]: certificate verification failed (%s)",
- host->name, host->address, error);
- return FAIL;
- }
+ return tls_error(US"certificate verification failed", host, error);
construct_cipher_name(tls_session); /* Sets tls_cipher */
tls_active = fd;
static void
record_io_error(int ec, uschar *when, uschar *text)
{
-uschar *additional = US"";
+const char *msg;
if (ec == GNUTLS_E_FATAL_ALERT_RECEIVED)
- additional = string_sprintf(": %s",
+ msg = string_sprintf("%s: %s", gnutls_strerror(ec),
gnutls_alert_get_name(gnutls_alert_get(tls_session)));
-
-if (initialized == INITIALIZED_SERVER)
- log_write(0, LOG_MAIN, "TLS %s error on connection from %s: %s%s", when,
- (sender_fullhost != NULL)? sender_fullhost : US "local process",
- (ec == 0)? text : US gnutls_strerror(ec), additional);
-
else
- log_write(0, LOG_MAIN, "TLS %s error on connection to %s [%s]: %s%s", when,
- client_host->name, client_host->address,
- (ec == 0)? text : US gnutls_strerror(ec), additional);
+ msg = gnutls_strerror(ec);
+
+tls_error(when, client_host, msg);
}
receive_ungetc = smtp_ungetc;
receive_feof = smtp_feof;
receive_ferror = smtp_ferror;
+ receive_smtp_buffered = smtp_buffered;
gnutls_deinit(tls_session);
tls_session = NULL;
ssl_xfer_error = 1;
return EOF;
}
-
+#ifndef DISABLE_DKIM
+ dkim_exim_verify_feed(ssl_xfer_buffer, inbytes);
+#endif
ssl_xfer_buffer_hwm = inbytes;
ssl_xfer_buffer_lwm = 0;
}
tls_active = -1;
}
+
+
+
+/*************************************************
+* Report the library versions. *
+*************************************************/
+
+/* See a description in tls-openssl.c for an explanation of why this exists.
+
+Arguments: a FILE* to print the results to
+Returns: nothing
+*/
+
+void
+tls_version_report(FILE *f)
+{
+fprintf(f, "Library version: GnuTLS: Compile: %s\n"
+ " Runtime: %s\n",
+ LIBGNUTLS_VERSION,
+ gnutls_check_version(NULL));
+}
+
/* End of tls-gnu.c */
git://git.exim.org / exim.git / blobdiff