X-Git-Url: https://git.exim.org/users/jgh/exim.git/blobdiff_plain/6a2c32cb705e73820c29e965394333f2874ba770..13a4b4c1810a1a9f3c956f1e92807a0d86c6f5bf:/src/src/auths/gsasl_exim.c diff --git a/src/src/auths/gsasl_exim.c b/src/src/auths/gsasl_exim.c index 06c91ea3f..b50c78056 100644 --- a/src/src/auths/gsasl_exim.c +++ b/src/src/auths/gsasl_exim.c @@ -2,6 +2,7 @@ * Exim - an Internet mail transport agent * *************************************************/ +/* Copyright (c) The Exim Maintainers 2019 */ /* Copyright (c) University of Cambridge 1995 - 2018 */ /* See the file NOTICE for conditions of use and distribution. */ @@ -26,6 +27,7 @@ sense in all contexts. For some, we can do checks at init time. */ #include "../exim.h" +#define CHANNELBIND_HACK #ifndef AUTH_GSASL /* dummy function to satisfy compilers when we link in an "empty" file. */ @@ -37,57 +39,79 @@ static void dummy(int x) { dummy2(x-1); } #include #include "gsasl_exim.h" + +#if GSASL_VERSION_MINOR >= 9 +# define EXIM_GSASL_HAVE_SCRAM_SHA_256 + +# if GSASL_VERSION_PATCH >= 1 +# define EXIM_GSASL_SCRAM_S_KEY +# endif +#endif + + /* 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) {} +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*/ @@ -125,8 +149,8 @@ to be set up. */ 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); @@ -152,48 +176,55 @@ if (!gsasl_ctx) /* We don't need this except to log it for debugging. */ -if ((rc = gsasl_server_mechlist(gsasl_ctx, &p)) != 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) 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)); -HDEBUG(D_auth) debug_printf("GNU SASL supports: %s\n", p); + debug_printf("GNU SASL supports: %s\n", once); + } -supported = gsasl_client_support_p(gsasl_ctx, CCS ob->server_mech); -if (!supported) +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); +ablock->server = TRUE; + if ( !ablock->server_condition && ( 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", + { + 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 && 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->server = FALSE; + HDEBUG(D_auth) debug_printf("%s authenticator: " + "Need server_realm for %s mechanism\n", 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) ablock->server = TRUE; -ablock->client = FALSE; +ablock->client = ob->client_username && ob->client_password; } @@ -207,21 +238,38 @@ int rc = 0; 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) { - 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))) + { + 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); @@ -243,6 +291,56 @@ return rc; } +/************************************************* +* 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 + 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"; +#ifdef EXIM_GSASL_SCRAM_S_KEY + case GSASL_SCRAM_CLIENTKEY: return US"SCRAM_CLIENTKEY"; +#endif + 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); +} + /************************************************* * Server entry point * *************************************************/ @@ -261,9 +359,30 @@ 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); +#ifndef DISABLE_TLS +if (tls_in.channelbinding && ob->server_channelbinding) + { +# ifdef EXPERIMENTAL_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 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)", @@ -273,10 +392,9 @@ if ((rc = gsasl_server_start(gsasl_ctx, CCS ob->server_mech, &sctx)) != GSASL_OK } /* 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); @@ -292,7 +410,7 @@ if (ob->server_realm) gsasl_property_set(sctx, GSASL_QOPS, "qop-auth"); #ifndef DISABLE_TLS -if (tls_channelbinding_b64) +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 @@ -316,8 +434,9 @@ if (tls_channelbinding_b64) { 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 + gsasl_property_set(sctx, GSASL_CB_TLS_UNIQUE, CCS tls_in.channelbinding); +# endif } else HDEBUG(D_auth) @@ -374,8 +493,9 @@ do { goto STOP_INTERACTION; } + /*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((uschar **)&received, US to_send); + exim_error = auth_get_no64_data(USS &received, US to_send); if (to_send) { @@ -391,6 +511,21 @@ do { 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 */ @@ -434,19 +569,66 @@ switch (exim_rc) return GSASL_AUTHENTICATION_ERROR; } + +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""; +auth_vars[i] = expand_nstring[j] = propval; +expand_nlength[j] = Ustrlen(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 +prop_from_option(Gsasl_session * sctx, Gsasl_property prop, + const uschar * option) +{ +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 *propval; +uschar *s, *propval; int cbrc = GSASL_NO_CALLBACK; 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; @@ -455,15 +637,9 @@ switch (prop) { 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; @@ -472,16 +648,11 @@ switch (prop) case GSASL_VALIDATE_EXTERNAL: 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); @@ -491,17 +662,11 @@ switch (prop) case GSASL_VALIDATE_ANONYMOUS: 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); @@ -518,13 +683,8 @@ switch (prop) 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. */ @@ -534,47 +694,46 @@ switch (prop) 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]); - - if (!(tmps = CS expand_string(ob->server_password))) + 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 @@ -586,7 +745,7 @@ switch (prop) 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; } @@ -597,6 +756,33 @@ return cbrc; } +/******************************************************************************/ + +#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; +int rc; + +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 * *************************************************/ @@ -606,29 +792,169 @@ return cbrc; int auth_gsasl_client( auth_instance *ablock, /* authenticator block */ - smtp_inblock * sx, /* connection */ + void * sx, /* connection */ int timeout, /* command timeout */ 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("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) + { +# ifdef EXPERIMENTAL_TLS_RESUME + if (!tls_out.ext_master_secret && tls_out.resumption == RESUME_USED) + { /* per RFC 7677 section 4 */ + 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 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_SCRAM_SALTED_PASSWORD, ob->client_spassword, + 0, buffer, buffsize) + && + !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 + gsasl_property_set(sctx, GSASL_CB_TLS_UNIQUE, CCS 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; + + rc = gsasl_step64(sctx, CS s, CSS &outstr); + + 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; + if (outstr && *outstr) 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: HDEBUG(D_auth) - debug_printf("Client side NOT IMPLEMENTED: you should not see this!\n"); -/* NOT IMPLEMENTED */ -return FAIL; + { + const uschar * s = CUS gsasl_property_fast(sctx, GSASL_SCRAM_SALTED_PASSWORD); + if (s) debug_printf(" - SaltedPassword: '%s'\n", s); + } + +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) + { + case GSASL_CB_TLS_UNIQUE: + HDEBUG(D_auth) + debug_printf(" filling in\n"); + gsasl_property_set(sctx, GSASL_CB_TLS_UNIQUE, CCS tls_out.channelbinding); + break; + default: + HDEBUG(D_auth) + debug_printf(" not providing one\n"); + break; + } +return GSASL_NO_CALLBACK; } /************************************************* @@ -645,6 +971,11 @@ fprintf(f, "Library version: GNU SASL: Compile: %s\n" GSASL_VERSION, runtime); } + + +/* Dummy */ +void auth_gsasl_macros(void) {} + #endif /*!MACRO_PREDEF*/ #endif /* AUTH_GSASL */