* Exim - an Internet mail transport agent *
*************************************************/
+/* Copyright (c) The Exim Maintainers 2019 - 2022 */
/* Copyright (c) University of Cambridge 1995 - 2018 */
/* See the file NOTICE for conditions of use and distribution. */
+/* SPDX-License-Identifier: GPL-2.0-or-later */
/* Copyright (c) Twitter Inc 2012
Author: Phil Pennock <pdp@exim.org> */
#include <gsasl.h>
#include "gsasl_exim.h"
+
+#if GSASL_VERSION_MAJOR == 2
+
+# define EXIM_GSASL_HAVE_SCRAM_SHA_256
+# define EXIM_GSASL_SCRAM_S_KEY
+# if GSASL_VERSION_MINOR >= 1
+# define EXIM_GSASL_HAVE_EXPORTER
+# elif GSASL_VERSION_PATCH >= 1
+# define EXIM_GSASL_HAVE_EXPORTER
+# endif
+
+#elif GSASL_VERSION_MAJOR == 1
+# if GSASL_VERSION_MINOR >= 10
+# define EXIM_GSASL_HAVE_SCRAM_SHA_256
+# define EXIM_GSASL_SCRAM_S_KEY
+
+# elif GSASL_VERSION_MINOR == 9
+# define EXIM_GSASL_HAVE_SCRAM_SHA_256
+
+# if GSASL_VERSION_PATCH >= 1
+# define EXIM_GSASL_SCRAM_S_KEY
+# endif
+# if GSASL_VERSION_PATCH < 2
+# define CHANNELBIND_HACK
+# endif
+
+# else
+# define CHANNELBIND_HACK
+# endif
+#endif
+
+/* Convenience for testing strings */
+
+#define STREQIC(Foo, Bar) (strcmpic((Foo), (Bar)) == 0)
+
+
/* Authenticator-specific options. */
/* I did have server_*_condition options for various mechanisms, but since
we only ever handle one mechanism at a time, I didn't see the point in keeping
that. In case someone sees a point, I've left the condition_check() API
alone. */
+#define LOFF(field) OPT_OFF(auth_gsasl_options_block, field)
+
optionlist auth_gsasl_options[] = {
- { "server_channelbinding", opt_bool,
- (void *)(offsetof(auth_gsasl_options_block, server_channelbinding)) },
- { "server_hostname", opt_stringptr,
- (void *)(offsetof(auth_gsasl_options_block, server_hostname)) },
- { "server_mech", opt_stringptr,
- (void *)(offsetof(auth_gsasl_options_block, server_mech)) },
- { "server_password", opt_stringptr,
- (void *)(offsetof(auth_gsasl_options_block, server_password)) },
- { "server_realm", opt_stringptr,
- (void *)(offsetof(auth_gsasl_options_block, server_realm)) },
- { "server_scram_iter", opt_stringptr,
- (void *)(offsetof(auth_gsasl_options_block, server_scram_iter)) },
- { "server_scram_salt", opt_stringptr,
- (void *)(offsetof(auth_gsasl_options_block, server_scram_salt)) },
- { "server_service", opt_stringptr,
- (void *)(offsetof(auth_gsasl_options_block, server_service)) }
+ { "client_authz", opt_stringptr, LOFF(client_authz) },
+ { "client_channelbinding", opt_bool, LOFF(client_channelbinding) },
+ { "client_password", opt_stringptr, LOFF(client_password) },
+ { "client_spassword", opt_stringptr, LOFF(client_spassword) },
+ { "client_username", opt_stringptr, LOFF(client_username) },
+
+ { "server_channelbinding", opt_bool, LOFF(server_channelbinding) },
+ { "server_hostname", opt_stringptr, LOFF(server_hostname) },
+#ifdef EXIM_GSASL_SCRAM_S_KEY
+ { "server_key", opt_stringptr, LOFF(server_key) },
+#endif
+ { "server_mech", opt_stringptr, LOFF(server_mech) },
+ { "server_password", opt_stringptr, LOFF(server_password) },
+ { "server_realm", opt_stringptr, LOFF(server_realm) },
+ { "server_scram_iter", opt_stringptr, LOFF(server_scram_iter) },
+ { "server_scram_salt", opt_stringptr, LOFF(server_scram_salt) },
+#ifdef EXIM_GSASL_SCRAM_S_KEY
+ { "server_skey", opt_stringptr, LOFF(server_s_key) },
+#endif
+ { "server_service", opt_stringptr, LOFF(server_service) }
};
-/* GSASL_SCRAM_SALTED_PASSWORD documented only for client, so not implementing
-hooks to avoid cleartext passwords in the Exim server. */
int auth_gsasl_options_count =
sizeof(auth_gsasl_options)/sizeof(optionlist);
/* Defaults for the authenticator-specific options. */
auth_gsasl_options_block auth_gsasl_option_defaults = {
- US"smtp", /* server_service */
- US"$primary_hostname", /* server_hostname */
- NULL, /* server_realm */
- NULL, /* server_mech */
- NULL, /* server_password */
- NULL, /* server_scram_iter */
- NULL, /* server_scram_salt */
- FALSE /* server_channelbinding */
+ .server_service = US"smtp",
+ .server_hostname = US"$primary_hostname",
+ .server_scram_iter = US"4096",
+ /* all others zero/null */
};
#ifdef MACRO_PREDEF
+# include "../macro_predef.h"
/* Dummy values */
void auth_gsasl_init(auth_instance *ablock) {}
int auth_gsasl_server(auth_instance *ablock, uschar *data) {return 0;}
-int auth_gsasl_client(auth_instance *ablock, smtp_inblock * sx,
+int auth_gsasl_client(auth_instance *ablock, void * sx,
int timeout, uschar *buffer, int buffsize) {return 0;}
-void auth_gsasl_version_report(FILE *f) {}
+gstring * auth_gsasl_version_report(gstring * g) {return NULL;}
+
+void
+auth_gsasl_macros(void)
+{
+# ifdef EXIM_GSASL_HAVE_SCRAM_SHA_256
+ builtin_macro_create(US"_HAVE_AUTH_GSASL_SCRAM_SHA_256");
+# endif
+# ifdef EXIM_GSASL_SCRAM_S_KEY
+ builtin_macro_create(US"_HAVE_AUTH_GSASL_SCRAM_S_KEY");
+# endif
+}
#else /*!MACRO_PREDEF*/
void
auth_gsasl_init(auth_instance *ablock)
{
-char *p;
-int rc, supported;
+static char * once = NULL;
+int rc;
auth_gsasl_options_block *ob =
(auth_gsasl_options_block *)(ablock->options_block);
the default for the mechanism name; we don't handle multiple mechanisms
in one authenticator, but the same driver can be used multiple times. */
-if (ob->server_mech == NULL)
+if (!ob->server_mech)
ob->server_mech = string_copy(ablock->public_name);
/* Can get multiple session contexts from one library context, so just
initialise the once. */
-if (gsasl_ctx == NULL) {
- rc = gsasl_init(&gsasl_ctx);
- if (rc != GSASL_OK) {
+
+if (!gsasl_ctx)
+ {
+ if ((rc = gsasl_init(&gsasl_ctx)) != GSASL_OK)
log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: "
"couldn't initialise GNU SASL library: %s (%s)",
ablock->name, gsasl_strerror_name(rc), gsasl_strerror(rc));
- }
+
gsasl_callback_set(gsasl_ctx, main_callback);
-}
+ }
/* We don't need this except to log it for debugging. */
-rc = gsasl_server_mechlist(gsasl_ctx, &p);
-if (rc != GSASL_OK)
- log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: "
- "failed to retrieve list of mechanisms: %s (%s)",
- ablock->name, gsasl_strerror_name(rc), gsasl_strerror(rc));
-HDEBUG(D_auth) debug_printf("GNU SASL supports: %s\n", p);
-supported = gsasl_client_support_p(gsasl_ctx, CCS ob->server_mech);
-if (!supported)
+HDEBUG(D_auth) if (!once)
+ {
+ if ((rc = gsasl_server_mechlist(gsasl_ctx, &once)) != GSASL_OK)
+ log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: "
+ "failed to retrieve list of mechanisms: %s (%s)",
+ ablock->name, gsasl_strerror_name(rc), gsasl_strerror(rc));
+
+ debug_printf("GNU SASL supports: %s\n", once);
+ }
+
+if (!gsasl_client_support_p(gsasl_ctx, CCS ob->server_mech))
log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: "
"GNU SASL does not support mechanism \"%s\"",
ablock->name, ob->server_mech);
-if ((ablock->server_condition == NULL) &&
- (streqic(ob->server_mech, US"EXTERNAL") ||
- streqic(ob->server_mech, US"ANONYMOUS") ||
- streqic(ob->server_mech, US"PLAIN") ||
- streqic(ob->server_mech, US"LOGIN")))
- log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: "
- "Need server_condition for %s mechanism",
+if (ablock->server_condition)
+ ablock->server = TRUE;
+else if( ob->server_mech
+ && !STREQIC(ob->server_mech, US"EXTERNAL")
+ && !STREQIC(ob->server_mech, US"ANONYMOUS")
+ && !STREQIC(ob->server_mech, US"PLAIN")
+ && !STREQIC(ob->server_mech, US"LOGIN")
+ )
+ {
+ /* At present, for mechanisms we don't panic on absence of server_condition;
+ need to figure out the most generically correct approach to deciding when
+ it's critical and when it isn't. Eg, for simple validation (PLAIN mechanism,
+ etc) it clearly is critical.
+ */
+
+ ablock->server = FALSE;
+ HDEBUG(D_auth) debug_printf("%s authenticator: "
+ "Need server_condition for %s mechanism\n",
ablock->name, ob->server_mech);
+ }
/* This does *not* scale to new SASL mechanisms. Need a better way to ask
which properties will be needed. */
-if ((ob->server_realm == NULL) &&
- streqic(ob->server_mech, US"DIGEST-MD5"))
- log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: "
- "Need server_realm for %s mechanism",
- ablock->name, ob->server_mech);
-/* At present, for mechanisms we don't panic on absence of server_condition;
-need to figure out the most generically correct approach to deciding when
-it's critical and when it isn't. Eg, for simple validation (PLAIN mechanism,
-etc) it clearly is critical.
+if ( !ob->server_realm
+ && STREQIC(ob->server_mech, US"DIGEST-MD5"))
+ {
+ ablock->server = FALSE;
+ HDEBUG(D_auth) debug_printf("%s authenticator: "
+ "Need server_realm for %s mechanism\n",
+ ablock->name, ob->server_mech);
+ }
-So don't activate without server_condition, this might be relaxed in the future.
-*/
-if (ablock->server_condition != NULL) ablock->server = TRUE;
-ablock->client = FALSE;
+ablock->client = ob->client_username && ob->client_password;
}
struct callback_exim_state *cb_state =
(struct callback_exim_state *)gsasl_session_hook_get(sctx);
-HDEBUG(D_auth)
- debug_printf("GNU SASL Callback entered, prop=%d (loop prop=%d)\n",
- prop, callback_loop);
-
-if (cb_state == NULL)
+if (!cb_state)
{
- HDEBUG(D_auth) debug_printf(" not from our server/client processing.\n");
+ HDEBUG(D_auth) debug_printf("gsasl callback (%d) not from our server/client processing\n", prop);
+#ifdef CHANNELBIND_HACK
+ if (prop == GSASL_CB_TLS_UNIQUE)
+ {
+ uschar * s;
+ if ((s = gsasl_callback_hook_get(ctx))) /* Gross hack for early lib vers */
+ {
+ HDEBUG(D_auth) debug_printf("GSASL_CB_TLS_UNIQUE from ctx hook\n");
+ gsasl_property_set(sctx, GSASL_CB_TLS_UNIQUE, CS s);
+ }
+ else
+ {
+ HDEBUG(D_auth) debug_printf("GSASL_CB_TLS_UNIQUE! dummy for now\n");
+ gsasl_property_set(sctx, GSASL_CB_TLS_UNIQUE, "");
+ }
+ return GSASL_OK;
+ }
+#endif
return GSASL_NO_CALLBACK;
}
+HDEBUG(D_auth)
+ debug_printf("GNU SASL Callback entered, prop=%d (loop prop=%d)\n",
+ prop, callback_loop);
+
if (callback_loop > 0)
{
- /* Most likely is that we were asked for property foo, and to
- expand the string we asked for property bar to put into an auth
- variable, but property bar is not supplied for this mechanism. */
+ /* Most likely is that we were asked for property FOO, and to
+ expand the string we asked for property BAR to put into an auth
+ variable, but property BAR is not supplied for this mechanism. */
HDEBUG(D_auth)
debug_printf("Loop, asked for property %d while handling property %d\n",
prop, callback_loop);
}
+/*************************************************
+* Debug service function *
+*************************************************/
+static const uschar *
+gsasl_prop_code_to_name(Gsasl_property prop)
+{
+switch (prop)
+ {
+ case GSASL_AUTHID: return US"AUTHID";
+ case GSASL_AUTHZID: return US"AUTHZID";
+ case GSASL_PASSWORD: return US"PASSWORD";
+ case GSASL_ANONYMOUS_TOKEN: return US"ANONYMOUS_TOKEN";
+ case GSASL_SERVICE: return US"SERVICE";
+ case GSASL_HOSTNAME: return US"HOSTNAME";
+ case GSASL_GSSAPI_DISPLAY_NAME: return US"GSSAPI_DISPLAY_NAME";
+ case GSASL_PASSCODE: return US"PASSCODE";
+ case GSASL_SUGGESTED_PIN: return US"SUGGESTED_PIN";
+ case GSASL_PIN: return US"PIN";
+ case GSASL_REALM: return US"REALM";
+ case GSASL_DIGEST_MD5_HASHED_PASSWORD: return US"DIGEST_MD5_HASHED_PASSWORD";
+ case GSASL_QOPS: return US"QOPS";
+ case GSASL_QOP: return US"QOP";
+ case GSASL_SCRAM_ITER: return US"SCRAM_ITER";
+ case GSASL_SCRAM_SALT: return US"SCRAM_SALT";
+ case GSASL_SCRAM_SALTED_PASSWORD: return US"SCRAM_SALTED_PASSWORD";
+#ifdef EXIM_GSASL_SCRAM_S_KEY
+ case GSASL_SCRAM_STOREDKEY: return US"SCRAM_STOREDKEY";
+ case GSASL_SCRAM_SERVERKEY: return US"SCRAM_SERVERKEY";
+#endif
+#ifdef EXIM_GSASL_HAVE_EXPORTER /* v. 2.1.0 */
+ case GSASL_CB_TLS_EXPORTER: return US"CB_TLS_EXPORTER";
+#endif
+ case GSASL_CB_TLS_UNIQUE: return US"CB_TLS_UNIQUE";
+ case GSASL_SAML20_IDP_IDENTIFIER: return US"SAML20_IDP_IDENTIFIER";
+ case GSASL_SAML20_REDIRECT_URL: return US"SAML20_REDIRECT_URL";
+ case GSASL_OPENID20_REDIRECT_URL: return US"OPENID20_REDIRECT_URL";
+ case GSASL_OPENID20_OUTCOME_DATA: return US"OPENID20_OUTCOME_DATA";
+ case GSASL_SAML20_AUTHENTICATE_IN_BROWSER: return US"SAML20_AUTHENTICATE_IN_BROWSER";
+ case GSASL_OPENID20_AUTHENTICATE_IN_BROWSER: return US"OPENID20_AUTHENTICATE_IN_BROWSER";
+ case GSASL_VALIDATE_SIMPLE: return US"VALIDATE_SIMPLE";
+ case GSASL_VALIDATE_EXTERNAL: return US"VALIDATE_EXTERNAL";
+ case GSASL_VALIDATE_ANONYMOUS: return US"VALIDATE_ANONYMOUS";
+ case GSASL_VALIDATE_GSSAPI: return US"VALIDATE_GSSAPI";
+ case GSASL_VALIDATE_SECURID: return US"VALIDATE_SECURID";
+ case GSASL_VALIDATE_SAML20: return US"VALIDATE_SAML20";
+ case GSASL_VALIDATE_OPENID20: return US"VALIDATE_OPENID20";
+ }
+return CUS string_sprintf("(unknown prop: %d)", (int)prop);
+}
+
+static void
+preload_prop(Gsasl_session * sctx, Gsasl_property propcode, const uschar * val)
+{
+DEBUG(D_auth) debug_printf("preloading prop %s val %s\n",
+ gsasl_prop_code_to_name(propcode), val);
+gsasl_property_set(sctx, propcode, CCS val);
+}
+
/*************************************************
* Server entry point *
*************************************************/
/* For interface, see auths/README */
int
-auth_gsasl_server(auth_instance *ablock, uschar *initial_data)
+auth_gsasl_server(auth_instance * ablock, uschar * initial_data)
{
-char *tmps;
-char *to_send, *received;
-Gsasl_session *sctx = NULL;
-auth_gsasl_options_block *ob =
+uschar * tmps;
+char * to_send, * received;
+Gsasl_session * sctx = NULL;
+auth_gsasl_options_block * ob =
(auth_gsasl_options_block *)(ablock->options_block);
struct callback_exim_state cb_state;
int rc, auth_result, exim_error, exim_error_override;
HDEBUG(D_auth)
- debug_printf("GNU SASL: initialising session for %s, mechanism %s.\n",
+ debug_printf("GNU SASL: initialising session for %s, mechanism %s\n",
ablock->name, ob->server_mech);
-rc = gsasl_server_start(gsasl_ctx, CCS ob->server_mech, &sctx);
-if (rc != GSASL_OK)
+#ifndef DISABLE_TLS
+if (tls_in.channelbinding && ob->server_channelbinding)
+ {
+# ifndef DISABLE_TLS_RESUME
+ if (!tls_in.ext_master_secret && tls_in.resumption == RESUME_USED)
+ { /* per RFC 7677 section 4 */
+ HDEBUG(D_auth) debug_printf(
+ "channel binding not usable on resumed TLS without extended-master-secret");
+ return FAIL;
+ }
+# endif
+# ifdef CHANNELBIND_HACK
+/* This is a gross hack to get around the library before 1.9.2
+a) requiring that c-b was already set, at the _start() call, and
+b) caching a b64'd version of the binding then which it never updates. */
+
+ gsasl_callback_hook_set(gsasl_ctx, tls_in.channelbinding);
+# endif
+ }
+#endif
+
+if ((rc = gsasl_server_start(gsasl_ctx, CCS ob->server_mech, &sctx)) != GSASL_OK)
{
auth_defer_msg = string_sprintf("GNU SASL: session start failure: %s (%s)",
gsasl_strerror_name(rc), gsasl_strerror(rc));
}
/* Hereafter: gsasl_finish(sctx) please */
-gsasl_session_hook_set(sctx, (void *)ablock);
cb_state.ablock = ablock;
cb_state.currently = CURRENTLY_SERVER;
-gsasl_session_hook_set(sctx, (void *)&cb_state);
+gsasl_session_hook_set(sctx, &cb_state);
-tmps = CS expand_string(ob->server_service);
-gsasl_property_set(sctx, GSASL_SERVICE, tmps);
-tmps = CS expand_string(ob->server_hostname);
-gsasl_property_set(sctx, GSASL_HOSTNAME, tmps);
+tmps = expand_string(ob->server_service);
+preload_prop(sctx, GSASL_SERVICE, tmps);
+tmps = expand_string(ob->server_hostname);
+preload_prop(sctx, GSASL_HOSTNAME, tmps);
if (ob->server_realm)
{
- tmps = CS expand_string(ob->server_realm);
+ tmps = expand_string(ob->server_realm);
if (tmps && *tmps)
- gsasl_property_set(sctx, GSASL_REALM, tmps);
+ preload_prop(sctx, GSASL_REALM, tmps);
}
/* We don't support protection layers. */
-gsasl_property_set(sctx, GSASL_QOPS, "qop-auth");
-#ifdef SUPPORT_TLS
-if (tls_channelbinding_b64)
+preload_prop(sctx, GSASL_QOPS, US "qop-auth");
+
+#ifndef DISABLE_TLS
+if (tls_in.channelbinding)
{
/* Some auth mechanisms can ensure that both sides are talking withing the
same security context; for TLS, this means that even if a bad certificate
would then result in mechanism name changes on a library update, we
have little choice but to default it off and let the admin choose to
enable it. *sigh*
+
+ Earlier library versions need this set early, during the _start() call,
+ so we had to misuse gsasl_callback_hook_set/get() as a data transfer
+ mech for the callback done at that time to get the bind-data. More recently
+ the callback is done (if needed) during the first gsasl_stop(). We know
+ the bind-data here so can set it (and should not get a callback).
*/
if (ob->server_channelbinding)
{
HDEBUG(D_auth) debug_printf("Auth %s: Enabling channel-binding\n",
ablock->name);
- gsasl_property_set(sctx, GSASL_CB_TLS_UNIQUE,
- CCS tls_channelbinding_b64);
+# ifndef CHANNELBIND_HACK
+ preload_prop(sctx,
+# ifdef EXIM_GSASL_HAVE_EXPORTER
+ tls_in.channelbind_exporter ? GSASL_CB_TLS_EXPORTER :
+# endif
+ GSASL_CB_TLS_UNIQUE,
+ tls_in.channelbinding);
+# endif
}
else
- {
HDEBUG(D_auth)
debug_printf("Auth %s: Not enabling channel-binding (data available)\n",
ablock->name);
- }
}
else
HDEBUG(D_auth)
exim_error = exim_error_override = OK;
do {
- rc = gsasl_step64(sctx, received, &to_send);
-
- switch (rc)
+ switch (rc = gsasl_step64(sctx, received, &to_send))
{
case GSASL_OK:
if (!to_send)
goto STOP_INTERACTION;
}
- if ((rc == GSASL_NEEDS_MORE) ||
- (to_send && *to_send))
- exim_error =
- auth_get_no64_data((uschar **)&received, US to_send);
+ /*XXX having our caller send the final smtp "235" is unfortunate; wastes a roundtrip */
+ if ((rc == GSASL_NEEDS_MORE) || (to_send && *to_send))
+ exim_error = auth_get_no64_data(USS &received, US to_send);
if (to_send)
{
STOP_INTERACTION:
auth_result = rc;
+HDEBUG(D_auth)
+ {
+ const uschar * s;
+ if ((s = CUS gsasl_property_fast(sctx, GSASL_SCRAM_ITER)))
+ debug_printf(" - itercnt: '%s'\n", s);
+ if ((s = CUS gsasl_property_fast(sctx, GSASL_SCRAM_SALT)))
+ debug_printf(" - salt: '%s'\n", s);
+#ifdef EXIM_GSASL_SCRAM_S_KEY
+ if ((s = CUS gsasl_property_fast(sctx, GSASL_SCRAM_SERVERKEY)))
+ debug_printf(" - ServerKey: '%s'\n", s);
+ if ((s = CUS gsasl_property_fast(sctx, GSASL_SCRAM_STOREDKEY)))
+ debug_printf(" - StoredKey: '%s'\n", s);
+#endif
+ }
+
gsasl_finish(sctx);
/* Can return: OK DEFER FAIL CANCELLED BAD64 UNEXPECTED */
static int
condition_check(auth_instance *ablock, uschar *label, uschar *condition_string)
{
-int exim_rc;
-
-exim_rc = auth_check_some_cond(ablock, label, condition_string, FAIL);
-
-if (exim_rc == OK)
- return GSASL_OK;
-else if (exim_rc == DEFER)
+int exim_rc = auth_check_some_cond(ablock, label, condition_string, FAIL);
+switch (exim_rc)
{
- sasl_error_should_defer = TRUE;
- return GSASL_AUTHENTICATION_ERROR;
+ case OK: return GSASL_OK;
+ case DEFER: sasl_error_should_defer = TRUE;
+ return GSASL_AUTHENTICATION_ERROR;
+ case FAIL: return GSASL_AUTHENTICATION_ERROR;
+ default: log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: "
+ "Unhandled return from checking %s: %d",
+ ablock->name, label, exim_rc);
}
-else if (exim_rc == FAIL)
- return GSASL_AUTHENTICATION_ERROR;
-log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: "
- "Unhandled return from checking %s: %d",
- ablock->name, label, exim_rc);
/* NOTREACHED */
return GSASL_AUTHENTICATION_ERROR;
}
+
+/* Set the "next" $auth[n] and increment expand_nmax */
+
+static void
+set_exim_authvar_from_prop(Gsasl_session * sctx, Gsasl_property prop)
+{
+uschar * propval = US gsasl_property_fast(sctx, prop);
+int i = expand_nmax, j = i + 1;
+propval = propval ? string_copy(propval) : US"";
+HDEBUG(D_auth) debug_printf("auth[%d] <= %s'%s'\n",
+ j, gsasl_prop_code_to_name(prop), propval);
+expand_nstring[j] = propval;
+expand_nlength[j] = Ustrlen(propval);
+if (i < AUTH_VARS) auth_vars[i] = propval;
+expand_nmax = j;
+}
+
+static void
+set_exim_authvars_from_a_az_r_props(Gsasl_session * sctx)
+{
+if (expand_nmax > 0 ) return;
+
+/* Asking for GSASL_AUTHZID calls back into us if we use
+gsasl_property_get(), thus the use of gsasl_property_fast().
+Do we really want to hardcode limits per mechanism? What happens when
+a new mechanism is added to the library. It *shouldn't* result in us
+needing to add more glue, since avoiding that is a large part of the
+point of SASL. */
+
+set_exim_authvar_from_prop(sctx, GSASL_AUTHID);
+set_exim_authvar_from_prop(sctx, GSASL_AUTHZID);
+set_exim_authvar_from_prop(sctx, GSASL_REALM);
+}
+
+
static int
-server_callback(Gsasl *ctx, Gsasl_session *sctx, Gsasl_property prop, auth_instance *ablock)
+prop_from_option(Gsasl_session * sctx, Gsasl_property prop,
+ const uschar * option)
{
-char *tmps;
-uschar *propval;
+HDEBUG(D_auth) debug_printf(" %s\n", gsasl_prop_code_to_name(prop));
+if (option)
+ {
+ set_exim_authvars_from_a_az_r_props(sctx);
+ option = expand_cstring(option);
+ HDEBUG(D_auth) debug_printf(" '%s'\n", option);
+ if (*option)
+ gsasl_property_set(sctx, prop, CCS option);
+ return GSASL_OK;
+ }
+HDEBUG(D_auth) debug_printf(" option not set\n");
+return GSASL_NO_CALLBACK;
+}
+
+static int
+server_callback(Gsasl *ctx, Gsasl_session *sctx, Gsasl_property prop,
+ auth_instance *ablock)
+{
+char * tmps;
+uschar * s;
int cbrc = GSASL_NO_CALLBACK;
-auth_gsasl_options_block *ob =
+auth_gsasl_options_block * ob =
(auth_gsasl_options_block *)(ablock->options_block);
-HDEBUG(D_auth)
- debug_printf("GNU SASL callback %d for %s/%s as server\n",
- prop, ablock->name, ablock->public_name);
+HDEBUG(D_auth) debug_printf("GNU SASL callback %s for %s/%s as server\n",
+ gsasl_prop_code_to_name(prop), ablock->name, ablock->public_name);
for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
expand_nmax = 0;
{
case GSASL_VALIDATE_SIMPLE:
/* GSASL_AUTHID, GSASL_AUTHZID, and GSASL_PASSWORD */
- propval = US gsasl_property_fast(sctx, GSASL_AUTHID);
- auth_vars[0] = expand_nstring[1] = propval ? propval : US"";
- propval = US gsasl_property_fast(sctx, GSASL_AUTHZID);
- auth_vars[1] = expand_nstring[2] = propval ? propval : US"";
- propval = US gsasl_property_fast(sctx, GSASL_PASSWORD);
- auth_vars[2] = expand_nstring[3] = propval ? propval : US"";
- expand_nmax = 3;
- for (int i = 1; i <= 3; ++i)
- expand_nlength[i] = Ustrlen(expand_nstring[i]);
+ set_exim_authvar_from_prop(sctx, GSASL_AUTHID);
+ set_exim_authvar_from_prop(sctx, GSASL_AUTHZID);
+ set_exim_authvar_from_prop(sctx, GSASL_PASSWORD);
cbrc = condition_check(ablock, US"server_condition", ablock->server_condition);
checked_server_condition = TRUE;
break;
case GSASL_VALIDATE_EXTERNAL:
- if (ablock->server_condition == NULL)
+ if (!ablock->server_condition)
{
- HDEBUG(D_auth) debug_printf("No server_condition supplied, to validate EXTERNAL.\n");
+ HDEBUG(D_auth) debug_printf("No server_condition supplied, to validate EXTERNAL\n");
cbrc = GSASL_AUTHENTICATION_ERROR;
break;
}
- propval = US gsasl_property_fast(sctx, GSASL_AUTHZID);
- /* We always set $auth1, even if only to empty string. */
- auth_vars[0] = expand_nstring[1] = propval ? propval : US"";
- expand_nlength[1] = Ustrlen(expand_nstring[1]);
- expand_nmax = 1;
+ set_exim_authvar_from_prop(sctx, GSASL_AUTHZID);
cbrc = condition_check(ablock,
US"server_condition (EXTERNAL)", ablock->server_condition);
break;
case GSASL_VALIDATE_ANONYMOUS:
- if (ablock->server_condition == NULL)
+ if (!ablock->server_condition)
{
- HDEBUG(D_auth) debug_printf("No server_condition supplied, to validate ANONYMOUS.\n");
+ HDEBUG(D_auth) debug_printf("No server_condition supplied, to validate ANONYMOUS\n");
cbrc = GSASL_AUTHENTICATION_ERROR;
break;
}
- propval = US gsasl_property_fast(sctx, GSASL_ANONYMOUS_TOKEN);
- /* We always set $auth1, even if only to empty string. */
- auth_vars[0] = expand_nstring[1] = propval ? propval : US"";
- expand_nlength[1] = Ustrlen(expand_nstring[1]);
- expand_nmax = 1;
+ set_exim_authvar_from_prop(sctx, GSASL_ANONYMOUS_TOKEN);
cbrc = condition_check(ablock,
US"server_condition (ANONYMOUS)", ablock->server_condition);
by the SASL integration after authentication; protected against tampering
(if the SASL mechanism supports that, which Kerberos does) but is
unverified, same as normal for other mechanisms.
-
- First coding, we had these values swapped, but for consistency and prior
+ First coding, we had these values swapped, but for consistency and prior
to the first release of Exim with this authenticator, they've been
switched to match the ordering of GSASL_VALIDATE_SIMPLE. */
- propval = US gsasl_property_fast(sctx, GSASL_GSSAPI_DISPLAY_NAME);
- auth_vars[0] = expand_nstring[1] = propval ? propval : US"";
- propval = US gsasl_property_fast(sctx, GSASL_AUTHZID);
- auth_vars[1] = expand_nstring[2] = propval ? propval : US"";
- expand_nmax = 2;
- for (int i = 1; i <= 2; ++i)
- expand_nlength[i] = Ustrlen(expand_nstring[i]);
+
+ set_exim_authvar_from_prop(sctx, GSASL_GSSAPI_DISPLAY_NAME);
+ set_exim_authvar_from_prop(sctx, GSASL_AUTHZID);
/* In this one case, it perhaps makes sense to default back open?
But for consistency, let's just mandate server_condition here too. */
+
cbrc = condition_check(ablock,
US"server_condition (GSSAPI family)", ablock->server_condition);
checked_server_condition = TRUE;
break;
+ case GSASL_SCRAM_ITER:
+ cbrc = prop_from_option(sctx, prop, ob->server_scram_iter);
+ break;
+
+ case GSASL_SCRAM_SALT:
+ cbrc = prop_from_option(sctx, prop, ob->server_scram_salt);
+ break;
+
+#ifdef EXIM_GSASL_SCRAM_S_KEY
+ case GSASL_SCRAM_STOREDKEY:
+ cbrc = prop_from_option(sctx, prop, ob->server_s_key);
+ break;
+
+ case GSASL_SCRAM_SERVERKEY:
+ cbrc = prop_from_option(sctx, prop, ob->server_key);
+ break;
+#endif
+
case GSASL_PASSWORD:
- /* DIGEST-MD5: GSASL_AUTHID, GSASL_AUTHZID and GSASL_REALM
+ /* SCRAM-*: GSASL_AUTHID, GSASL_AUTHZID and GSASL_REALM
+ DIGEST-MD5: GSASL_AUTHID, GSASL_AUTHZID and GSASL_REALM
CRAM-MD5: GSASL_AUTHID
PLAIN: GSASL_AUTHID and GSASL_AUTHZID
LOGIN: GSASL_AUTHID
*/
- if (ob->server_scram_iter)
- {
- tmps = CS expand_string(ob->server_scram_iter);
- gsasl_property_set(sctx, GSASL_SCRAM_ITER, tmps);
- }
- if (ob->server_scram_salt)
+ set_exim_authvars_from_a_az_r_props(sctx);
+
+ if (!(s = ob->server_password))
{
- tmps = CS expand_string(ob->server_scram_salt);
- gsasl_property_set(sctx, GSASL_SCRAM_SALT, tmps);
+ HDEBUG(D_auth) debug_printf("option not set\n");
+ break;
}
- /* Asking for GSASL_AUTHZID calls back into us if we use
- gsasl_property_get(), thus the use of gsasl_property_fast().
- Do we really want to hardcode limits per mechanism? What happens when
- a new mechanism is added to the library. It *shouldn't* result in us
- needing to add more glue, since avoiding that is a large part of the
- point of SASL. */
- propval = US gsasl_property_fast(sctx, GSASL_AUTHID);
- auth_vars[0] = expand_nstring[1] = propval ? propval : US"";
- propval = US gsasl_property_fast(sctx, GSASL_AUTHZID);
- auth_vars[1] = expand_nstring[2] = propval ? propval : US"";
- propval = US gsasl_property_fast(sctx, GSASL_REALM);
- auth_vars[2] = expand_nstring[3] = propval ? propval : US"";
- expand_nmax = 3;
- for (int i = 1; i <= 3; ++i)
- expand_nlength[i] = Ustrlen(expand_nstring[i]);
-
- tmps = CS expand_string(ob->server_password);
- if (tmps == NULL)
+ if (!(tmps = CS expand_string(s)))
{
- sasl_error_should_defer = f.expand_string_forcedfail ? FALSE : TRUE;
+ sasl_error_should_defer = !f.expand_string_forcedfail;
HDEBUG(D_auth) debug_printf("server_password expansion failed, so "
"can't tell GNU SASL library the password for %s\n", auth_vars[0]);
return GSASL_AUTHENTICATION_ERROR;
}
+ HDEBUG(D_auth) debug_printf(" set\n");
gsasl_property_set(sctx, GSASL_PASSWORD, tmps);
+
/* This is inadequate; don't think Exim's store stacks are geared
for memory wiping, so expanding strings will leave stuff laying around.
But no need to compound the problem, so get rid of the one we can. */
- memset(tmps, '\0', strlen(tmps));
+
+ if (US tmps != s) memset(tmps, '\0', strlen(tmps));
cbrc = GSASL_OK;
break;
default:
- HDEBUG(D_auth) debug_printf("Unrecognised callback: %d\n", prop);
+ HDEBUG(D_auth) debug_printf(" Unrecognised callback: %d\n", prop);
cbrc = GSASL_NO_CALLBACK;
}
}
+/******************************************************************************/
+
+#define PROP_OPTIONAL BIT(0)
+
+static BOOL
+set_client_prop(Gsasl_session * sctx, Gsasl_property prop, uschar * val,
+ unsigned flags, uschar * buffer, int buffsize)
+{
+uschar * s;
+
+if (!val) return !!(flags & PROP_OPTIONAL);
+if (!(s = expand_string(val)) || !(flags & PROP_OPTIONAL) && !*s)
+ {
+ string_format(buffer, buffsize, "%s", expand_string_message);
+ return FALSE;
+ }
+if (*s)
+ {
+ HDEBUG(D_auth) debug_printf("%s: set %s = '%s'\n", __FUNCTION__,
+ gsasl_prop_code_to_name(prop), s);
+ gsasl_property_set(sctx, prop, CS s);
+ }
+
+return TRUE;
+}
+
/*************************************************
* Client entry point *
*************************************************/
int
auth_gsasl_client(
- auth_instance *ablock, /* authenticator block */
- smtp_inblock * sx, /* connection */
+ auth_instance * ablock, /* authenticator block */
+ void * sx, /* connection */
int timeout, /* command timeout */
- uschar *buffer, /* buffer for reading response */
+ uschar * buffer, /* buffer for reading response */
int buffsize) /* size of buffer */
{
+auth_gsasl_options_block * ob =
+ (auth_gsasl_options_block *)(ablock->options_block);
+Gsasl_session * sctx = NULL;
+struct callback_exim_state cb_state;
+uschar * s;
+BOOL initial = TRUE;
+int rc, yield = FAIL;
+
HDEBUG(D_auth)
- debug_printf("Client side NOT IMPLEMENTED: you should not see this!\n");
-/* NOT IMPLEMENTED */
-return FAIL;
+ debug_printf("GNU SASL: initialising session for %s, mechanism %s\n",
+ ablock->name, ob->server_mech);
+
+*buffer = 0;
+
+#ifndef DISABLE_TLS
+if (tls_out.channelbinding && ob->client_channelbinding)
+ {
+# ifndef DISABLE_TLS_RESUME
+ if (!tls_out.ext_master_secret && tls_out.resumption == RESUME_USED)
+ { /* Per RFC 7677 section 4. See also RFC 7627, "Triple Handshake"
+ vulnerability, and https://www.mitls.org/pages/attacks/3SHAKE */
+ string_format(buffer, buffsize, "%s",
+ "channel binding not usable on resumed TLS without extended-master-secret");
+ return FAIL;
+ }
+# endif
+# ifdef CHANNELBIND_HACK
+ /* This is a gross hack to get around the library before 1.9.2
+ a) requiring that c-b was already set, at the _start() call, and
+ b) caching a b64'd version of the binding then which it never updates. */
+
+ gsasl_callback_hook_set(gsasl_ctx, tls_out.channelbinding);
+# endif
+ }
+#endif
+
+if ((rc = gsasl_client_start(gsasl_ctx, CCS ob->server_mech, &sctx)) != GSASL_OK)
+ {
+ string_format(buffer, buffsize, "GNU SASL: session start failure: %s (%s)",
+ gsasl_strerror_name(rc), gsasl_strerror(rc));
+ HDEBUG(D_auth) debug_printf("%s\n", buffer);
+ return ERROR;
+ }
+
+cb_state.ablock = ablock;
+cb_state.currently = CURRENTLY_CLIENT;
+gsasl_session_hook_set(sctx, &cb_state);
+
+/* Set properties */
+
+if ( !set_client_prop(sctx, GSASL_PASSWORD, ob->client_password,
+ 0, buffer, buffsize)
+ || !set_client_prop(sctx, GSASL_AUTHID, ob->client_username,
+ 0, buffer, buffsize)
+ || !set_client_prop(sctx, GSASL_AUTHZID, ob->client_authz,
+ PROP_OPTIONAL, buffer, buffsize)
+ )
+ return ERROR;
+
+#ifndef DISABLE_TLS
+if (tls_out.channelbinding)
+ if (ob->client_channelbinding)
+ {
+ HDEBUG(D_auth) debug_printf("Auth %s: Enabling channel-binding\n",
+ ablock->name);
+# ifndef CHANNELBIND_HACK
+ preload_prop(sctx,
+# ifdef EXIM_GSASL_HAVE_EXPORTER
+ tls_out.channelbind_exporter ? GSASL_CB_TLS_EXPORTER :
+# endif
+ GSASL_CB_TLS_UNIQUE,
+ tls_out.channelbinding);
+# endif
+ }
+ else
+ HDEBUG(D_auth)
+ debug_printf("Auth %s: Not enabling channel-binding (data available)\n",
+ ablock->name);
+#endif
+
+/* Run the SASL conversation with the server */
+
+for(s = NULL; ;)
+ {
+ uschar * outstr;
+ BOOL fail = TRUE;
+
+ rc = gsasl_step64(sctx, CS s, CSS &outstr);
+
+ if (rc == GSASL_NEEDS_MORE || rc == GSASL_OK)
+ {
+ fail = initial
+ ? smtp_write_command(sx, SCMD_FLUSH,
+ outstr ? "AUTH %s %s\r\n" : "AUTH %s\r\n",
+ ablock->public_name, outstr) <= 0
+ : outstr
+ ? smtp_write_command(sx, SCMD_FLUSH, "%s\r\n", outstr) <= 0
+ : FALSE;
+ free(outstr);
+ if (fail)
+ {
+ yield = FAIL_SEND;
+ goto done;
+ }
+ initial = FALSE;
+ }
+
+ if (rc != GSASL_NEEDS_MORE)
+ {
+ if (rc != GSASL_OK)
+ {
+ string_format(buffer, buffsize, "gsasl: %s", gsasl_strerror(rc));
+ break;
+ }
+
+ /* expecting a final 2xx from the server, accepting the AUTH */
+
+ if (smtp_read_response(sx, buffer, buffsize, '2', timeout))
+ yield = OK;
+ break; /* from SASL sequence loop */
+ }
+
+ /* 2xx or 3xx response is acceptable. If 2xx, no further input */
+
+ if (!smtp_read_response(sx, buffer, buffsize, '3', timeout))
+ if (errno == 0 && buffer[0] == '2')
+ buffer[4] = '\0';
+ else
+ {
+ yield = FAIL;
+ goto done;
+ }
+ s = buffer + 4;
+ }
+
+done:
+if (yield == OK)
+ {
+ expand_nmax = 0;
+ set_exim_authvar_from_prop(sctx, GSASL_AUTHID);
+ set_exim_authvar_from_prop(sctx, GSASL_SCRAM_ITER);
+ set_exim_authvar_from_prop(sctx, GSASL_SCRAM_SALT);
+ set_exim_authvar_from_prop(sctx, GSASL_SCRAM_SALTED_PASSWORD);
+ }
+
+gsasl_finish(sctx);
+return yield;
}
static int
client_callback(Gsasl *ctx, Gsasl_session *sctx, Gsasl_property prop, auth_instance *ablock)
{
-int cbrc = GSASL_NO_CALLBACK;
-HDEBUG(D_auth)
- debug_printf("GNU SASL callback %d for %s/%s as client\n",
- prop, ablock->name, ablock->public_name);
-
-HDEBUG(D_auth)
- debug_printf("Client side NOT IMPLEMENTED: you should not see this!\n");
-
-return cbrc;
+HDEBUG(D_auth) debug_printf("GNU SASL callback %s for %s/%s as client\n",
+ gsasl_prop_code_to_name(prop), ablock->name, ablock->public_name);
+switch (prop)
+ {
+#ifdef EXIM_GSASL_HAVE_EXPORTER
+ case GSASL_CB_TLS_EXPORTER: /* Should never get called for this, as pre-set */
+ if (!tls_out.channelbind_exporter) break;
+ HDEBUG(D_auth) debug_printf(" filling in\n");
+ gsasl_property_set(sctx, GSASL_CB_TLS_EXPORTER, CCS tls_out.channelbinding);
+ return GSASL_OK;
+#endif
+ case GSASL_CB_TLS_UNIQUE: /* Should never get called for this, as pre-set */
+#ifdef EXIM_GSASL_HAVE_EXPORTER
+ if (tls_out.channelbind_exporter) break;
+#endif
+ HDEBUG(D_auth) debug_printf(" filling in\n");
+ gsasl_property_set(sctx, GSASL_CB_TLS_UNIQUE, CCS tls_out.channelbinding);
+ return GSASL_OK;
+ case GSASL_SCRAM_SALTED_PASSWORD:
+ {
+ uschar * client_spassword =
+ ((auth_gsasl_options_block *) ablock->options_block)->client_spassword;
+ uschar dummy[4];
+ HDEBUG(D_auth) if (!client_spassword)
+ debug_printf(" client_spassword option unset\n");
+ if (client_spassword)
+ {
+ expand_nmax = 0;
+ set_exim_authvar_from_prop(sctx, GSASL_AUTHID);
+ set_exim_authvar_from_prop(sctx, GSASL_SCRAM_ITER);
+ set_exim_authvar_from_prop(sctx, GSASL_SCRAM_SALT);
+ set_client_prop(sctx, GSASL_SCRAM_SALTED_PASSWORD, client_spassword,
+ 0, dummy, sizeof(dummy));
+ for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
+ expand_nmax = 0;
+ }
+ break;
+ }
+ default:
+ HDEBUG(D_auth)
+ debug_printf(" not providing one\n");
+ break;
+ }
+return GSASL_NO_CALLBACK;
}
/*************************************************
* Diagnostic API *
*************************************************/
-void
-auth_gsasl_version_report(FILE *f)
+gstring *
+auth_gsasl_version_report(gstring * g)
{
-const char *runtime;
-runtime = gsasl_check_version(NULL);
-fprintf(f, "Library version: GNU SASL: Compile: %s\n"
- " Runtime: %s\n",
- GSASL_VERSION, runtime);
+return string_fmt_append(g, "Library version: GNU SASL: Compile: %s\n"
+ " Runtime: %s\n",
+ GSASL_VERSION, gsasl_check_version(NULL));
}
+
+
+/* Dummy */
+void auth_gsasl_macros(void) {}
+
#endif /*!MACRO_PREDEF*/
#endif /* AUTH_GSASL */
git://git.exim.org / exim.git / blobdiff