From 44bbabb570db6e700a31469a0faf2ac27bf3bfe0 Mon Sep 17 00:00:00 2001 From: Phil Pennock Date: Sun, 5 Feb 2012 19:13:32 -0500 Subject: [PATCH] Implemented gsasl driver for authentication. Missing: documentation; tests. Tested: PLAIN auth. Status: probably buggy --- src/scripts/MakeLinks | 2 + src/src/EDITME | 4 +- src/src/auths/Makefile | 4 +- src/src/auths/check_serv_cond.c | 43 ++- src/src/auths/cyrus_sasl.c | 2 +- src/src/auths/cyrus_sasl.h | 1 + src/src/auths/get_no64_data.c | 4 +- src/src/auths/gsasl_exim.c | 587 ++++++++++++++++++++++++++++++++ src/src/auths/gsasl_exim.h | 42 +++ src/src/config.h.defaults | 1 + src/src/drtables.c | 35 +- src/src/exim.c | 13 +- src/src/exim.h | 8 - src/src/functions.h | 2 + src/src/globals.h | 5 + src/src/structs.h | 2 + src/src/tls-gnu.c | 20 +- src/src/tls.c | 1 + 18 files changed, 748 insertions(+), 28 deletions(-) create mode 100644 src/src/auths/gsasl_exim.c create mode 100644 src/src/auths/gsasl_exim.h diff --git a/src/scripts/MakeLinks b/src/scripts/MakeLinks index 082659c99..f7d00030c 100755 --- a/src/scripts/MakeLinks +++ b/src/scripts/MakeLinks @@ -123,6 +123,8 @@ ln -s ../../src/auths/call_radius.c call_radius.c ln -s ../../src/auths/check_serv_cond.c check_serv_cond.c ln -s ../../src/auths/cyrus_sasl.c cyrus_sasl.c ln -s ../../src/auths/cyrus_sasl.h cyrus_sasl.h +ln -s ../../src/auths/gsasl_exim.c gsasl_exim.c +ln -s ../../src/auths/gsasl_exim.h gsasl_exim.h ln -s ../../src/auths/get_data.c get_data.c ln -s ../../src/auths/get_no64_data.c get_no64_data.c ln -s ../../src/auths/md5.c md5.c diff --git a/src/src/EDITME b/src/src/EDITME index a180cd5cd..7e426eaab 100644 --- a/src/src/EDITME +++ b/src/src/EDITME @@ -553,6 +553,7 @@ FIXED_NEVER_USERS=root # AUTH_CRAM_MD5=yes # AUTH_CYRUS_SASL=yes # AUTH_DOVECOT=yes +# AUTH_GSASL=yes # AUTH_PLAINTEXT=yes # AUTH_SPA=yes @@ -560,9 +561,10 @@ FIXED_NEVER_USERS=root #------------------------------------------------------------------------------ # If you specified AUTH_CYRUS_SASL above, you should ensure that you have the # Cyrus SASL library installed before trying to build Exim, and you probably -# want to uncomment the following line: +# want to uncomment the first line below. Similarly for GNU SASL. # AUTH_LIBS=-lsasl2 +# AUTH_LIBS=-lgsasl #------------------------------------------------------------------------------ diff --git a/src/src/auths/Makefile b/src/src/auths/Makefile index 3e0e1a2cd..1354c8cd5 100644 --- a/src/src/auths/Makefile +++ b/src/src/auths/Makefile @@ -7,7 +7,8 @@ OBJ = auth-spa.o b64decode.o b64encode.o call_pam.o call_pwcheck.o \ call_radius.o check_serv_cond.o cram_md5.o cyrus_sasl.o dovecot.o \ - get_data.o get_no64_data.o md5.o plaintext.o pwcheck.o sha1.o \ + get_data.o get_no64_data.o gsasl_exim.o \ + md5.o plaintext.o pwcheck.o sha1.o \ spa.o xtextdecode.o xtextencode.o auths.a: $(OBJ) @@ -38,6 +39,7 @@ xtextencode.o: $(HDRS) xtextencode.c cram_md5.o: $(HDRS) cram_md5.c cram_md5.h cyrus_sasl.o: $(HDRS) cyrus_sasl.c cyrus_sasl.h dovecot.o: $(HDRS) dovecot.c dovecot.h +gsasl_exim.o: $(HDRS) gsasl_exim.c gsasl_exim.h plaintext.o: $(HDRS) plaintext.c plaintext.h spa.o: $(HDRS) spa.c spa.h diff --git a/src/src/auths/check_serv_cond.c b/src/src/auths/check_serv_cond.c index 476d112ae..c10ff1be4 100644 --- a/src/src/auths/check_serv_cond.c +++ b/src/src/auths/check_serv_cond.c @@ -16,8 +16,8 @@ by all authenticators. */ *************************************************/ /* This function is called from the server code of all authenticators. For -plaintext, it is always called: the argument cannot be empty, because for -plaintext, setting server_condition is what enables it as a server +plaintext and gsasl, it is always called: the argument cannot be empty, because +for those, setting server_condition is what enables it as a server authenticator. For all the other authenticators, this function is called after they have authenticated, to enable additional authorization to be done. @@ -31,13 +31,41 @@ Returns: int auth_check_serv_cond(auth_instance *ablock) +{ + return auth_check_some_cond(ablock, + US"server_condition", ablock->server_condition, OK); +} + + +/************************************************* +* Check some server condition * +*************************************************/ + +/* This underlies server_condition, but is also used for some more generic + checks. + +Arguments: + ablock the authenticator's instance block + label debugging label naming the string checked + condition the condition string to be expanded and checked + unset value to return on NULL condition + +Returns: + OK success (or unset=OK) + DEFER couldn't complete the check + FAIL authentication failed +*/ + +int +auth_check_some_cond(auth_instance *ablock, + uschar *label, uschar *condition, int unset) { uschar *cond; HDEBUG(D_auth) { int i; - debug_printf("%s authenticator:\n", ablock->name); + debug_printf("%s authenticator %s:\n", ablock->name, label); for (i = 0; i < AUTH_VARS; i++) { if (auth_vars[i] != NULL) @@ -51,8 +79,13 @@ HDEBUG(D_auth) /* For the plaintext authenticator, server_condition is never NULL. For the rest, an unset condition lets everything through. */ -if (ablock->server_condition == NULL) return OK; -cond = expand_string(ablock->server_condition); +/* For server_condition, an unset condition lets everything through. +For plaintext/gsasl authenticators, it will have been pre-checked to prevent +this. We return the unset scenario value given to us, which for +server_condition will be OK and otherwise will typically be FAIL. */ + +if (condition == NULL) return unset; +cond = expand_string(condition); HDEBUG(D_auth) { diff --git a/src/src/auths/cyrus_sasl.c b/src/src/auths/cyrus_sasl.c index fea1def38..df7abc928 100644 --- a/src/src/auths/cyrus_sasl.c +++ b/src/src/auths/cyrus_sasl.c @@ -113,7 +113,7 @@ if(ob->server_mech == NULL) * authenticator of type whatever mechanism we're using */ -cbs[0].proc = &mysasl_config; +cbs[0].proc = (int(*)(void))&mysasl_config; cbs[0].context = ob->server_mech; rc=sasl_server_init(cbs, "exim"); diff --git a/src/src/auths/cyrus_sasl.h b/src/src/auths/cyrus_sasl.h index 7e62e63aa..031e783ed 100644 --- a/src/src/auths/cyrus_sasl.h +++ b/src/src/auths/cyrus_sasl.h @@ -31,5 +31,6 @@ extern void auth_cyrus_sasl_init(auth_instance *); extern int auth_cyrus_sasl_server(auth_instance *, uschar *); extern int auth_cyrus_sasl_client(auth_instance *, smtp_inblock *, smtp_outblock *, int, uschar *, int); +extern void auth_cyrus_sasl_version_report(FILE *f); /* End of cyrus_sasl.h */ diff --git a/src/src/auths/get_no64_data.c b/src/src/auths/get_no64_data.c index 4055c0411..ea5fd6f6d 100644 --- a/src/src/auths/get_no64_data.c +++ b/src/src/auths/get_no64_data.c @@ -14,8 +14,8 @@ /* This function is used by authentication drivers to output a challenge to the SMTP client and read the response line. This version does not use base -64 encoding for the text on the 334 line. It is used by the SPA and dovecot -authenticators. +64 encoding for the text on the 334 line. It is used by the SPA, dovecot +and gsasl authenticators. Arguments: aptr set to point to the response (which is in big_buffer) diff --git a/src/src/auths/gsasl_exim.c b/src/src/auths/gsasl_exim.c new file mode 100644 index 000000000..e88bd2578 --- /dev/null +++ b/src/src/auths/gsasl_exim.c @@ -0,0 +1,587 @@ +/************************************************* +* Exim - an Internet mail transport agent * +*************************************************/ + +/* Copyright (c) University of Cambridge 1995 - 2012 */ +/* See the file NOTICE for conditions of use and distribution. */ + +/* Copyright (c) Twitter Inc 2012 */ + +/* Interface to GNU SASL library for generic authentication. */ + +/* Trade-offs: + +GNU SASL does not provide authentication data itself, so we have to expose +that decision to configuration. For some mechanisms, we need to act much +like plaintext. For others, we only need to be able to provide some +evaluated data on demand. There's no abstracted way (ie, without hardcoding +knowledge of authenticators here) to know which need what properties; we +can't query a session or the library for "we will need these for mechanism X". + +So: we always require server_condition, even if sometimes it will just be +set as "yes". We do provide a number of other hooks, which might not make +sense in all contexts. For some, we can do checks at init time. +*/ + +#include "../exim.h" + +#ifndef AUTH_GSASL +/* dummy function to satisfy compilers when we link in an "empty" file. */ +static void dummy(int x) { dummy(x-1); } +#else + +#include +#include "gsasl_exim.h" + +/* 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. */ +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)) } +}; +/* 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 */ +}; + +/* "Globals" for managing the gsasl interface. */ + +static Gsasl *gsasl_ctx = NULL; +static int + main_callback(Gsasl *ctx, Gsasl_session *sctx, Gsasl_property prop); +static int + server_callback(Gsasl *ctx, Gsasl_session *sctx, Gsasl_property prop, auth_instance *ablock); +static int + client_callback(Gsasl *ctx, Gsasl_session *sctx, Gsasl_property prop, auth_instance *ablock); + +static BOOL sasl_error_should_defer = FALSE; +static Gsasl_property callback_loop = 0; +static BOOL checked_server_condition = FALSE; + +enum { CURRENTLY_SERVER = 1, CURRENTLY_CLIENT = 2 }; + +struct callback_exim_state { + auth_instance *ablock; + int currently; +}; + + +/************************************************* +* Initialization entry point * +*************************************************/ + +/* Called for each instance, after its options have been read, to +enable consistency checks to be done, or anything else that needs +to be set up. */ + +void +auth_gsasl_init(auth_instance *ablock) +{ + char *p; + int rc, supported; + auth_gsasl_options_block *ob = + (auth_gsasl_options_block *)(ablock->options_block); + + /* As per existing Cyrus glue, use the authenticator's public name as + 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) + 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) { + 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, (const char *)ob->server_mech); + if (!supported) + 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) && + (strcmpic(ob->server_mech, US"EXTERNAL") || + strcmpic(ob->server_mech, US"ANONYMOUS") || + strcmpic(ob->server_mech, US"PLAIN") || + strcmpic(ob->server_mech, US"LOGIN"))) + log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: " + "Need server_condition 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. + + 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; +} + + +/* GNU SASL uses one top-level callback, registered at library level. +We dispatch to client and server functions instead. */ + +static int +main_callback(Gsasl *ctx, Gsasl_session *sctx, Gsasl_property prop) +{ + int rc = 0; + struct callback_exim_state *cb_state = + (struct callback_exim_state *)gsasl_session_hook_get(sctx); + + HDEBUG(D_auth) debug_printf("Callback entered, prop=%d (loop prop=%d)\n", + prop, callback_loop); + + if (cb_state == NULL) { + HDEBUG(D_auth) debug_printf(" not from our server/client processing.\n"); + return GSASL_NO_CALLBACK; + } + + 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. */ + HDEBUG(D_auth) + debug_printf("Loop, asked for property %d while handling property %d\n", + prop, callback_loop); + return GSASL_NO_CALLBACK; + } + callback_loop = prop; + + if (cb_state->currently == CURRENTLY_CLIENT) + rc = client_callback(ctx, sctx, prop, cb_state->ablock); + else if (cb_state->currently == CURRENTLY_SERVER) + rc = server_callback(ctx, sctx, prop, cb_state->ablock); + else { + log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: " + "unhandled callback state, bug in Exim", cb_state->ablock->name); + /* NOTREACHED */ + } + + callback_loop = 0; + return rc; +} + + +/************************************************* +* Server entry point * +*************************************************/ + +/* For interface, see auths/README */ + +int +auth_gsasl_server(auth_instance *ablock, uschar *initial_data) +{ + char *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", + ablock->name, ob->server_mech); + + rc = gsasl_server_start(gsasl_ctx, (const char *)ob->server_mech, &sctx); + if (rc != GSASL_OK) { + auth_defer_msg = string_sprintf("GNU SASL: session start failure: %s (%s)", + gsasl_strerror_name(rc), gsasl_strerror(rc)); + HDEBUG(D_auth) debug_printf("%s\n", auth_defer_msg); + return DEFER; + } + /* 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); + + 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); + if (ob->server_realm) { + tmps = CS expand_string(ob->server_realm); + if (tmps && *tmps) { + gsasl_property_set(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) { + /* 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 + has been accepted, they remain MitM-proof because both sides must be within + the same negotiated session; if someone is terminating one sesson and + proxying data on within a second, authentication will fail. + + We might not have this available, depending upon TLS implementation, + ciphersuite, phase of moon ... + + If we do, it results in extra SASL mechanisms being available; here, + Exim's one-mechanism-per-authenticator potentially causes problems. + It depends upon how GNU SASL will implement the PLUS variants of GS2 + and whether it automatically mandates a switch to the bound PLUS + if the data is available. Since default-on, despite being more secure, + 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* + */ + 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, + (const char *) tls_channelbinding_b64); + } else { + HDEBUG(D_auth) + debug_printf("Auth %s: Not enabling channel-binding (data available)\n", + ablock->name); + } + } else { + HDEBUG(D_auth) + debug_printf("Auth %s: no channel-binding data available\n", + ablock->name); + } +#endif + + checked_server_condition = FALSE; + + received = CS initial_data; + to_send = NULL; + exim_error = exim_error_override = OK; + + do { + rc = gsasl_step64(sctx, received, &to_send); + + switch (rc) { + case GSASL_OK: + goto STOP_INTERACTION; + + case GSASL_NEEDS_MORE: + break; + + case GSASL_AUTHENTICATION_ERROR: + case GSASL_INTEGRITY_ERROR: + case GSASL_NO_AUTHID: + case GSASL_NO_ANONYMOUS_TOKEN: + case GSASL_NO_AUTHZID: + case GSASL_NO_PASSWORD: + case GSASL_NO_PASSCODE: + case GSASL_NO_PIN: + case GSASL_BASE64_ERROR: + HDEBUG(D_auth) debug_printf("GNU SASL permanent error: %s (%s)\n", + gsasl_strerror_name(rc), gsasl_strerror(rc)); + log_write(0, LOG_REJECT, "%s authenticator (%s):\n " + "GNU SASL permanent failure: %s (%s)", + ablock->name, ob->server_mech, + gsasl_strerror_name(rc), gsasl_strerror(rc)); + if (rc == GSASL_BASE64_ERROR) + exim_error_override = BAD64; + goto STOP_INTERACTION; + + default: + auth_defer_msg = string_sprintf("GNU SASL temporary error: %s (%s)", + gsasl_strerror_name(rc), gsasl_strerror(rc)); + HDEBUG(D_auth) debug_printf("%s\n", auth_defer_msg); + exim_error_override = DEFER; + goto STOP_INTERACTION; + } + + exim_error = + auth_get_no64_data((uschar **)&received, (uschar *)to_send); + if (exim_error) + break; /* handles * cancelled check */ + + } while (rc == GSASL_NEEDS_MORE); + +STOP_INTERACTION: + auth_result = rc; + + gsasl_finish(sctx); + + /* Can return: OK DEFER FAIL CANCELLED BAD64 UNEXPECTED */ + + if (exim_error != OK) + return exim_error; + + if (auth_result != GSASL_OK) { + HDEBUG(D_auth) debug_printf("authentication returned %s (%s)\n", + gsasl_strerror_name(auth_result), gsasl_strerror(auth_result)); + if (exim_error_override != OK) + return exim_error_override; /* might be DEFER */ + if (sasl_error_should_defer) /* overriding auth failure SASL error */ + return DEFER; + return FAIL; + } + + /* Auth succeeded, check server_condition unless already done in callback */ + return checked_server_condition ? OK : auth_check_serv_cond(ablock); +} + +/* returns the GSASL status of expanding the Exim string given */ +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) { + sasl_error_should_defer = TRUE; + return GSASL_AUTHENTICATION_ERROR; + } 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; +} + +static int +server_callback(Gsasl *ctx, Gsasl_session *sctx, Gsasl_property prop, auth_instance *ablock) +{ + char *tmps; + uschar *propval; + int cbrc = GSASL_NO_CALLBACK; + int i; + 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); + + for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; + expand_nmax = 0; + + switch (prop) { + case GSASL_VALIDATE_SIMPLE: + /* GSASL_AUTHID, GSASL_AUTHZID, and GSASL_PASSWORD */ + propval = (uschar *) gsasl_property_get(sctx, GSASL_AUTHID); + auth_vars[0] = expand_nstring[1] = propval ? propval : US""; + propval = (uschar *) gsasl_property_get(sctx, GSASL_AUTHZID); + auth_vars[1] = expand_nstring[2] = propval ? propval : US""; + propval = (uschar *) gsasl_property_get(sctx, GSASL_PASSWORD); + auth_vars[2] = expand_nstring[3] = propval ? propval : US""; + expand_nmax = 3; + for (i = 1; i <= 3; ++i) + expand_nlength[i] = Ustrlen(expand_nstring[i]); + + cbrc = condition_check(ablock, US"server_condition", ablock->server_condition); + checked_server_condition = TRUE; + break; + + case GSASL_VALIDATE_EXTERNAL: + if (ablock->server_condition == NULL) { + HDEBUG(D_auth) debug_printf("No server_condition supplied, to validate EXTERNAL.\n"); + cbrc = GSASL_AUTHENTICATION_ERROR; + break; + } + propval = (uschar *) gsasl_property_get(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; + + cbrc = condition_check(ablock, + US"server_condition (EXTERNAL)", ablock->server_condition); + checked_server_condition = TRUE; + break; + + case GSASL_VALIDATE_ANONYMOUS: + if (ablock->server_condition == NULL) { + HDEBUG(D_auth) debug_printf("No server_condition supplied, to validate ANONYMOUS.\n"); + cbrc = GSASL_AUTHENTICATION_ERROR; + break; + } + propval = (uschar *) gsasl_property_get(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; + + cbrc = condition_check(ablock, + US"server_condition (ANONYMOUS)", ablock->server_condition); + checked_server_condition = TRUE; + break; + + case GSASL_VALIDATE_GSSAPI: + /* GSASL_AUTHZID and GSASL_GSSAPI_DISPLAY_NAME */ + propval = (uschar *) gsasl_property_get(sctx, GSASL_AUTHZID); + auth_vars[0] = expand_nstring[1] = propval ? propval : US""; + propval = (uschar *) gsasl_property_get(sctx, GSASL_GSSAPI_DISPLAY_NAME); + auth_vars[1] = expand_nstring[2] = propval ? propval : US""; + expand_nmax = 2; + for (i = 1; i <= 2; ++i) + expand_nlength[i] = Ustrlen(expand_nstring[i]); + + /* 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_PASSWORD: + /* 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) { + tmps = CS expand_string(ob->server_scram_salt); + gsasl_property_set(sctx, GSASL_SCRAM_SALT, tmps); + } + /* Asking for GSASL_AUTHZID will probably call back into us. + 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 = (uschar *) gsasl_property_get(sctx, GSASL_AUTHID); + auth_vars[0] = expand_nstring[1] = propval ? propval : US""; + propval = (uschar *) gsasl_property_get(sctx, GSASL_AUTHZID); + auth_vars[1] = expand_nstring[2] = propval ? propval : US""; + propval = (uschar *) gsasl_property_get(sctx, GSASL_REALM); + auth_vars[2] = expand_nstring[3] = propval ? propval : US""; + expand_nmax = 3; + for (i = 1; i <= 3; ++i) + expand_nlength[i] = Ustrlen(expand_nstring[i]); + + tmps = CS expand_string(ob->server_password); + if (tmps == NULL) { + sasl_error_should_defer = expand_string_forcedfail ? FALSE : TRUE; + 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; + } + 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)); + cbrc = GSASL_OK; + break; + + default: + HDEBUG(D_auth) debug_printf("Unrecognised callback: %d\n", prop); + cbrc = GSASL_NO_CALLBACK; + } + + HDEBUG(D_auth) debug_printf("Returning %s (%s)\n", + gsasl_strerror_name(cbrc), gsasl_strerror(cbrc)); + + return cbrc; +} + + +/************************************************* +* Client entry point * +*************************************************/ + +/* For interface, see auths/README */ + +int +auth_gsasl_client( + auth_instance *ablock, /* authenticator block */ + smtp_inblock *inblock, /* connection inblock */ + smtp_outblock *outblock, /* connection outblock */ + int timeout, /* command timeout */ + uschar *buffer, /* buffer for reading response */ + int buffsize) /* size of buffer */ +{ + HDEBUG(D_auth) + debug_printf("Client side NOT IMPLEMENTED: you should not see this!\n"); + /* NOT IMPLEMENTED */ + return FAIL; +} + +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; +} + +/************************************************* +* Diagnostic API * +*************************************************/ + +void +auth_gsasl_version_report(FILE *f) +{ + const char *runtime; + runtime = gsasl_check_version(NULL); + fprintf(f, "Library version: GNU SASL: Compile: %s\n" + " Runtime: %s\n", + GSASL_VERSION, runtime); +} + +#endif /* AUTH_GSASL */ + +/* End of gsasl_exim.c */ diff --git a/src/src/auths/gsasl_exim.h b/src/src/auths/gsasl_exim.h new file mode 100644 index 000000000..785b8538b --- /dev/null +++ b/src/src/auths/gsasl_exim.h @@ -0,0 +1,42 @@ +/************************************************* +* Exim - an Internet mail transport agent * +*************************************************/ + +/* Copyright (c) University of Cambridge 1995 - 2012 */ +/* See the file NOTICE for conditions of use and distribution. */ + +/* Copyright (c) Twitter Inc 2012 */ + +/* Interface to GNU SASL library for generic authentication. */ + +/* Authenticator-specific options. */ + +typedef struct { + uschar *server_service; + uschar *server_hostname; + uschar *server_realm; + uschar *server_mech; + uschar *server_password; + uschar *server_scram_iter; + uschar *server_scram_salt; + BOOL server_channelbinding; +} auth_gsasl_options_block; + +/* Data for reading the authenticator-specific options. */ + +extern optionlist auth_gsasl_options[]; +extern int auth_gsasl_options_count; + +/* Defaults for the authenticator-specific options. */ + +extern auth_gsasl_options_block auth_gsasl_option_defaults; + +/* The entry points for the mechanism */ + +extern void auth_gsasl_init(auth_instance *); +extern int auth_gsasl_server(auth_instance *, uschar *); +extern int auth_gsasl_client(auth_instance *, smtp_inblock *, + smtp_outblock *, int, uschar *, int); +extern void auth_gsasl_version_report(FILE *f); + +/* End of gsasl_exim.h */ diff --git a/src/src/config.h.defaults b/src/src/config.h.defaults index bc983c444..c562ee98c 100644 --- a/src/src/config.h.defaults +++ b/src/src/config.h.defaults @@ -20,6 +20,7 @@ it's a default value. */ #define AUTH_CRAM_MD5 #define AUTH_CYRUS_SASL #define AUTH_DOVECOT +#define AUTH_GSASL #define AUTH_PLAINTEXT #define AUTH_SPA diff --git a/src/src/drtables.c b/src/src/drtables.c index 37ecf4f4b..6e42ef94f 100644 --- a/src/src/drtables.c +++ b/src/src/drtables.c @@ -37,6 +37,10 @@ set to NULL for those that are not compiled into the binary. */ #include "auths/dovecot.h" #endif +#ifdef AUTH_GSASL +#include "auths/gsasl_exim.h" +#endif + #ifdef AUTH_PLAINTEXT #include "auths/plaintext.h" #endif @@ -58,7 +62,8 @@ auth_info auths_available[] = { sizeof(auth_cram_md5_options_block), auth_cram_md5_init, /* init function */ auth_cram_md5_server, /* server function */ - auth_cram_md5_client /* client function */ + auth_cram_md5_client, /* client function */ + NULL /* diagnostic function */ }, #endif @@ -71,7 +76,8 @@ auth_info auths_available[] = { sizeof(auth_cyrus_sasl_options_block), auth_cyrus_sasl_init, /* init function */ auth_cyrus_sasl_server, /* server function */ - NULL /* client function */ + NULL, /* client function */ + auth_cyrus_sasl_version_report /* diagnostic function */ }, #endif @@ -84,7 +90,22 @@ auth_info auths_available[] = { sizeof(auth_dovecot_options_block), auth_dovecot_init, /* init function */ auth_dovecot_server, /* server function */ - NULL /* client function */ + NULL, /* client function */ + NULL /* diagnostic function */ + }, +#endif + +#ifdef AUTH_GSASL + { + US"gsasl", /* lookup name */ + auth_gsasl_options, + &auth_gsasl_options_count, + &auth_gsasl_option_defaults, + sizeof(auth_gsasl_options_block), + auth_gsasl_init, /* init function */ + auth_gsasl_server, /* server function */ + NULL, /* client function */ + auth_gsasl_version_report /* diagnostic function */ }, #endif @@ -97,7 +118,8 @@ auth_info auths_available[] = { sizeof(auth_plaintext_options_block), auth_plaintext_init, /* init function */ auth_plaintext_server, /* server function */ - auth_plaintext_client /* client function */ + auth_plaintext_client, /* client function */ + NULL /* diagnostic function */ }, #endif @@ -110,11 +132,12 @@ auth_info auths_available[] = { sizeof(auth_spa_options_block), auth_spa_init, /* init function */ auth_spa_server, /* server function */ - auth_spa_client /* client function */ + auth_spa_client, /* client function */ + NULL /* diagnostic function */ }, #endif -{ US"", NULL, NULL, NULL, 0, NULL, NULL, NULL } +{ US"", NULL, NULL, NULL, 0, NULL, NULL, NULL, NULL } }; diff --git a/src/src/exim.c b/src/src/exim.c index a6c0d7832..b4ea01dcd 100644 --- a/src/src/exim.c +++ b/src/src/exim.c @@ -725,6 +725,8 @@ Returns: nothing static void show_whats_supported(FILE *f) { + auth_info *authi; + #ifdef DB_VERSION_STRING fprintf(f, "Berkeley DB: %s\n", DB_VERSION_STRING); #elif defined(BTREEVERSION) && defined(HASHVERSION) @@ -867,6 +869,9 @@ fprintf(f, "Authenticators:"); #ifdef AUTH_DOVECOT fprintf(f, " dovecot"); #endif +#ifdef AUTH_GSASL + fprintf(f, " gsasl"); +#endif #ifdef AUTH_PLAINTEXT fprintf(f, " plaintext"); #endif @@ -962,9 +967,11 @@ DEBUG(D_any) do { tls_version_report(f); #endif -#ifdef AUTH_CYRUS_SASL - auth_cyrus_sasl_version_report(f); -#endif + for (authi = auths_available; *authi->driver_name != '\0'; ++authi) { + if (authi->version_report) { + (*authi->version_report)(f); + } + } fprintf(f, "Library version: PCRE: Compile: %d.%d%s\n" " Runtime: %s\n", diff --git a/src/src/exim.h b/src/src/exim.h index a45ea0b30..626d33dae 100644 --- a/src/src/exim.h +++ b/src/src/exim.h @@ -538,12 +538,4 @@ default to EDQUOT if it exists, otherwise ENOSPC. */ #endif #endif -/* These are for reporting version information from various componenents, to -figure out what's actually happening. They need to be available to the main -function, so we declare them here. Unfortunate. */ - -#ifdef AUTH_CYRUS_SASL -extern void auth_cyrus_sasl_version_report(FILE *); -#endif - /* End of exim.h */ diff --git a/src/src/functions.h b/src/src/functions.h index 5efcbbb04..d2575946b 100644 --- a/src/src/functions.h +++ b/src/src/functions.h @@ -54,6 +54,8 @@ extern int auth_call_radius(uschar *, uschar **); extern int auth_call_saslauthd(uschar *, uschar *, uschar *, uschar *, uschar **); extern int auth_check_serv_cond(auth_instance *); +extern int auth_check_some_cond(auth_instance *, uschar *, uschar *, int); + extern int auth_get_data(uschar **, uschar *, int); extern int auth_get_no64_data(uschar **, uschar *); extern uschar *auth_xtextencode(uschar *, int); diff --git a/src/src/globals.h b/src/src/globals.h index 4ed3950df..1066306ac 100644 --- a/src/src/globals.h +++ b/src/src/globals.h @@ -90,6 +90,7 @@ extern uschar *openssl_options; /* OpenSSL compatibility options */ extern const pcre *regex_STARTTLS; /* For recognizing STARTTLS settings */ extern uschar *tls_advertise_hosts; /* host for which TLS is advertised */ extern uschar *tls_certificate; /* Certificate file */ +extern uschar *tls_channelbinding_b64; /* string of base64 channel binding */ extern uschar *tls_crl; /* CRL File */ extern uschar *tls_dhparam; /* DH param file */ extern BOOL tls_offered; /* Server offered TLS */ @@ -101,6 +102,10 @@ extern uschar *tls_verify_certificates;/* Path for certificates to check */ extern uschar *tls_verify_hosts; /* Mandatory client verification */ #endif +#ifdef USE_GNUTLS +extern +#endif + /* Input-reading functions for messages, so we can use special ones for incoming TCP/IP. */ diff --git a/src/src/structs.h b/src/src/structs.h index 3790c7fe8..9b51d0b7c 100644 --- a/src/src/structs.h +++ b/src/src/structs.h @@ -367,6 +367,8 @@ typedef struct auth_info { int, /* command timeout */ uschar *, /* buffer for reading response */ int); /* sizeof buffer */ + void (*version_report)( /* diagnostic version reporting */ + FILE *); /* I/O stream to print to */ } auth_info; diff --git a/src/src/tls-gnu.c b/src/src/tls-gnu.c index f77768fb8..2d1a327de 100644 --- a/src/src/tls-gnu.c +++ b/src/src/tls-gnu.c @@ -854,7 +854,10 @@ construct_cipher_name(gnutls_session 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))); @@ -871,6 +874,21 @@ string_format(cipherbuf, sizeof(cipherbuf), "%s:%s:%u", ver, 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 } diff --git a/src/src/tls.c b/src/src/tls.c index 7cb1550f3..d975a2c89 100644 --- a/src/src/tls.c +++ b/src/src/tls.c @@ -40,6 +40,7 @@ static int ssl_xfer_buffer_hwm = 0; static int ssl_xfer_eof = 0; static int ssl_xfer_error = 0; +uschar *tls_channelbinding_b64 = NULL; /************************************************* -- 2.30.2