From: Jeremy Harris Date: Sat, 7 Sep 2024 17:52:15 +0000 (+0100) Subject: pam dynamic module X-Git-Url: https://git.exim.org/exim.git/commitdiff_plain/7fba0a36b45d510611efe21df3523e89a9601ffd pam dynamic module --- diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff index fe94e46c7..935efb59a 100644 --- a/doc/doc-txt/NewStuff +++ b/doc/doc-txt/NewStuff @@ -14,7 +14,7 @@ Version 4.98 3. Events smtp:fail:protocol and smtp:fail:syntax - 4. JSON and LDAP lookup support, RADIUS, SPF, DKIM, DMARC and ARC support, + 4. JSON and LDAP lookup support, PAM, RADIUS, SPF, DKIM, DMARC and ARC support, all the router and authenticator drivers, and all the transport drivers except smtp, can now be built as loadable modules diff --git a/src/OS/Makefile-Base b/src/OS/Makefile-Base index ddd7cf5ac..22b56aae5 100644 --- a/src/OS/Makefile-Base +++ b/src/OS/Makefile-Base @@ -509,7 +509,7 @@ OBJ_LOOKUPS = lf_quote.o lf_check_file.o lf_sqlperform.o OBJ_ROUTERS = rf_change_domain.o rf_expand_data.o rf_get_errors_address.o \ rf_get_munge_headers.o rf_get_transport.o rf_get_ugid.o \ rf_lookup_hostlist.o rf_queue_add.o rf_self_action.o rf_set_ugid.o -OBJ_AUTHS = call_pam.o call_pwcheck.o check_serv_cond.o \ +OBJ_AUTHS = call_pwcheck.o check_serv_cond.o \ get_data.o get_no64_data.o pwcheck.o OBJ_EXIM = acl.o base64.o child.o crypt16.o daemon.o dbfn.o debug.o deliver.o \ @@ -968,9 +968,6 @@ rf_set_ugid.o: routers/rf_set_ugid.c auth-spa.o: auths/auth-spa.c @echo "$(CC) $<" $(FE)$(CC) -c $(CFLAGS) -I. $(INCLUDE) $< -call_pam.o: auths/call_pam.c - @echo "$(CC) $<" - $(FE)$(CC) -c $(CFLAGS) -I. $(INCLUDE) $< call_pwcheck.o: auths/call_pwcheck.c auths/pwcheck.h @echo "$(CC) $<" $(FE)$(CC) -c $(CFLAGS) -I. $(INCLUDE) $< diff --git a/src/scripts/Configure-Makefile b/src/scripts/Configure-Makefile index 96a6cce22..4fc917dc9 100755 --- a/src/scripts/Configure-Makefile +++ b/src/scripts/Configure-Makefile @@ -309,7 +309,7 @@ done <<-END routers ROUTER ACCEPT DNSLOOKUP IPLITERAL IPLOOKUP MANUALROUTE QUERYPROGRAM REDIRECT transports TRANSPORT APPENDFILE AUTOREPLY LMTP PIPE QUEUEFILE SMTP auths AUTH CRAM_MD5 CYRUS_SASL DOVECOT EXTERNAL GSASL HEIMDAL_GSSAPI PLAINTEXT SPA TLS - miscmods SUPPORT ARC _DKIM DMARC RADIUS SPF + miscmods SUPPORT ARC _DKIM DMARC PAM RADIUS SPF END # See if there is a definition of EXIM_PERL in what we have built so far. diff --git a/src/scripts/MakeLinks b/src/scripts/MakeLinks index 1b272a5c9..a3a3131a2 100755 --- a/src/scripts/MakeLinks +++ b/src/scripts/MakeLinks @@ -102,6 +102,7 @@ for f in dummy.c \ pdkim/crypt_ver.h pdkim/pdkim.c pdkim/pdkim.h \ pdkim/pdkim_hash.h pdkim/signing.c pdkim/signing.h \ dmarc.c dmarc.h dmarc_api.h \ + pam.c pam_api.h \ radius.c radius_api.h \ spf.c spf.h spf_api.h do diff --git a/src/src/EDITME b/src/src/EDITME index 9d458842a..c12d74c35 100644 --- a/src/src/EDITME +++ b/src/src/EDITME @@ -1089,6 +1089,8 @@ ZCAT_COMMAND=/usr/bin/zcat # distributions (see http://ftp.kernel.org/pub/linux/libs/pam/). The Exim # support, which is intended for use in conjunction with the SMTP AUTH # facilities, is included only when requested by the following setting: +# +# For a dynamic module build add SUPPORT_PAM=2 and SUPPORT_PAM_LIBS=-lpam # SUPPORT_PAM=yes @@ -1146,6 +1148,9 @@ ZCAT_COMMAND=/usr/bin/zcat # which is intended for use in conjunction with the SMTP AUTH facilities, # is included only when requested by setting the following parameter to the # location of your Radius configuration file: +# +# For a dynamic module build add SUPPORT_RADIUS=2 and (if needed) +# SUPPORT_RADIUS_LIBS=-l # RADIUS_CONFIG_FILE=/etc/radiusclient/radiusclient.conf # RADIUS_CONFIG_FILE=/etc/radius.conf diff --git a/src/src/auths/call_pam.c b/src/src/auths/call_pam.c deleted file mode 100644 index 3ff15711d..000000000 --- a/src/src/auths/call_pam.c +++ /dev/null @@ -1,205 +0,0 @@ -/************************************************* -* Exim - an Internet mail transport agent * -*************************************************/ - -/* Copyright (c) University of Cambridge 1995 - 2018 */ -/* Copyright (c) The Exim Maintainers 2020 - 2021 */ -/* See the file NOTICE for conditions of use and distribution. */ -/* SPDX-License-Identifier: GPL-2.0-or-later */ - -#include "../exim.h" - -/* This module contains functions that call the PAM authentication mechanism -defined by Sun for Solaris and also available for Linux and other OS. - -We can't just compile this code and allow the library mechanism to omit the -functions if they are not wanted, because we need to have the PAM headers -available for compiling. Therefore, compile these functions only if SUPPORT_PAM -is defined. However, some compilers don't like compiling empty modules, so keep -them happy with a dummy when skipping the rest. Make it reference itself to -stop picky compilers complaining that it is unused, and put in a dummy argument -to stop even pickier compilers complaining about infinite loops. -Then use a mutually-recursive pair as gcc is just getting stupid. */ - -#ifndef SUPPORT_PAM -static void dummy(int x); -static void dummy2(int x) { dummy(x-1); } -static void dummy(int x) { dummy2(x-1); } -#else /* SUPPORT_PAM */ - -#ifdef PAM_H_IN_PAM -#include -#else -#include -#endif - -/* According to the specification, it should be possible to have an application -data pointer passed to the conversation function. However, I was unable to get -this to work on Solaris 2.6, so static variables are used instead. */ - -static int pam_conv_had_error; -static const uschar *pam_args; -static BOOL pam_arg_ended; - - - -/************************************************* -* PAM conversation function * -*************************************************/ - -/* This function is passed to the PAM authentication function, and it calls it -back when it wants data from the client. The string list is in pam_args. When -we reach the end, we pass back an empty string once. If this function is called -again, it will give an error response. This is protection against something -crazy happening. - -Arguments: - num_msg number of messages associated with the call - msg points to an array of length num_msg of pam_message structures - resp set to point to the response block, which has to be got by - this function - appdata_ptr the application data pointer - not used because in Solaris - 2.6 it always arrived in pam_converse() as NULL - -Returns: a PAM return code -*/ - -static int -pam_converse (int num_msg, PAM_CONVERSE_ARG2_TYPE **msg, - struct pam_response **resp, void *appdata_ptr) -{ -int sep = 0; -struct pam_response *reply; - -/* It seems that PAM frees reply[] */ - -if ( pam_arg_ended - || !(reply = malloc(sizeof(struct pam_response) * num_msg))) - return PAM_CONV_ERR; - -for (int i = 0; i < num_msg; i++) - { - uschar *arg; - switch (msg[i]->msg_style) - { - case PAM_PROMPT_ECHO_ON: - case PAM_PROMPT_ECHO_OFF: - if (!(arg = string_nextinlist(&pam_args, &sep, NULL, 0))) - { - arg = US""; - pam_arg_ended = TRUE; - } - reply[i].resp = strdup(CCS arg); /* Use libc malloc, PAM frees resp directly*/ - reply[i].resp_retcode = PAM_SUCCESS; - break; - - case PAM_TEXT_INFO: /* Just acknowledge messages */ - case PAM_ERROR_MSG: - reply[i].resp_retcode = PAM_SUCCESS; - reply[i].resp = NULL; - break; - - default: /* Must be an error of some sort... */ - free(reply); - pam_conv_had_error = TRUE; - return PAM_CONV_ERR; - } - } - -*resp = reply; -return PAM_SUCCESS; -} - - - -/************************************************* -* Perform PAM authentication * -*************************************************/ - -/* This function calls the PAM authentication mechanism, passing over one or -more data strings. - -Arguments: - s a colon-separated list of strings - errptr where to point an error message - -Returns: OK if authentication succeeded - FAIL if authentication failed - ERROR some other error condition -*/ - -int -auth_call_pam(const uschar *s, uschar **errptr) -{ -pam_handle_t *pamh = NULL; -struct pam_conv pamc; -int pam_error; -int sep = 0; -uschar *user; - -/* Set up the input data structure: the address of the conversation function, -and a pointer to application data, which we don't use because I couldn't get it -to work under Solaris 2.6 - it always arrived in pam_converse() as NULL. */ - -pamc.conv = pam_converse; -pamc.appdata_ptr = NULL; - -/* Initialize the static data - the current input data, the error flag, and the -flag for data end. */ - -pam_args = s; -pam_conv_had_error = FALSE; -pam_arg_ended = FALSE; - -/* The first string in the list is the user. If this is an empty string, we -fail. PAM doesn't support authentication with an empty user (it prompts for it, -causing a potential mis-interpretation). */ - -user = string_nextinlist(&pam_args, &sep, NULL, 0); -if (user == NULL || user[0] == 0) return FAIL; - -/* Start off PAM interaction */ - -DEBUG(D_auth) - debug_printf("Running PAM authentication for user \"%s\"\n", user); - -pam_error = pam_start ("exim", CS user, &pamc, &pamh); - -/* Do the authentication - the pam_authenticate() will call pam_converse() to -get the data it wants. After successful authentication we call pam_acct_mgmt() -to apply any other restrictions (e.g. only some times of day). */ - -if (pam_error == PAM_SUCCESS) - { - pam_error = pam_authenticate (pamh, PAM_SILENT); - if (pam_error == PAM_SUCCESS && !pam_conv_had_error) - pam_error = pam_acct_mgmt (pamh, PAM_SILENT); - } - -/* Finish the PAM interaction - this causes it to clean up store etc. Unclear -what should be passed as the second argument. */ - -pam_end(pamh, PAM_SUCCESS); - -/* Sort out the return code. If not success, set the error message. */ - -if (pam_error == PAM_SUCCESS) - { - DEBUG(D_auth) debug_printf("PAM success\n"); - return OK; - } - -*errptr = US pam_strerror(pamh, pam_error); -DEBUG(D_auth) debug_printf("PAM error: %s\n", *errptr); - -if (pam_error == PAM_USER_UNKNOWN || - pam_error == PAM_AUTH_ERR || - pam_error == PAM_ACCT_EXPIRED) - return FAIL; - -return ERROR; -} - -#endif /* SUPPORT_PAM */ - -/* End of call_pam.c */ diff --git a/src/src/exim.h b/src/src/exim.h index 550f1a7bd..a3b7112a6 100644 --- a/src/src/exim.h +++ b/src/src/exim.h @@ -561,6 +561,9 @@ config.h, mytypes.h, and store.h, so we don't need to mention them explicitly. #ifdef RADIUS_CONFIG_FILE # include "miscmods/radius_api.h" #endif +#ifdef SUPPORT_PAM +# include "miscmods/pam_api.h" +#endif /* The following stuff must follow the inclusion of config.h because it requires various things that are set therein. */ diff --git a/src/src/expand.c b/src/src/expand.c index cdfe93cdc..d9e71897e 100644 --- a/src/src/expand.c +++ b/src/src/expand.c @@ -2767,12 +2767,19 @@ switch(cond_type = identify_operator(&s, &opname)) /* Various authentication tests - all optionally compiled */ case ECOND_PAM: - #ifdef SUPPORT_PAM - rc = auth_call_pam(sub[0], &expand_string_message); - goto END_AUTH; - #else - goto COND_FAILED_NOT_COMPILED; - #endif /* SUPPORT_PAM */ +#ifdef SUPPORT_PAM + { + const misc_module_info * mi = misc_mod_find(US"pam", NULL); + typedef int (*fn_t)(const uschar *, uschar **); + if (!mi) + goto COND_FAILED_NOT_COMPILED; + rc = (((fn_t *) mi->functions)[PAM_AUTH_CALL]) + (sub[0], &expand_string_message); + goto END_AUTH; + } +#else + goto COND_FAILED_NOT_COMPILED; +#endif /* SUPPORT_PAM */ case ECOND_RADIUS: #ifdef RADIUS_CONFIG_FILE diff --git a/src/src/functions.h b/src/src/functions.h index 493b2287e..cb470bcb3 100644 --- a/src/src/functions.h +++ b/src/src/functions.h @@ -111,7 +111,6 @@ extern void add_driver_info(driver_info **, const driver_info *, size_t); extern void assert_no_variables(void *, int, const char *, int); -extern int auth_call_pam(const uschar *, uschar **); extern int auth_call_pwcheck(uschar *, uschar **); extern int auth_call_saslauthd(const uschar *, const uschar *, const uschar *, const uschar *, uschar **); diff --git a/src/src/miscmods/Makefile b/src/src/miscmods/Makefile index a15fd9b38..8f53088ff 100644 --- a/src/src/miscmods/Makefile +++ b/src/src/miscmods/Makefile @@ -37,6 +37,8 @@ dkim.o dkim.so: $(HDRS) dkim.h dkim.c dkim_transport.c \ signing.h signing.c dmarc.o dmarc.so: $(HDRS) pdkim.h dmarc.h dmarc.c dummy.o: dummy.c +pam.o pam.so: $(HDRS) pam.c +radius.o radius.so: $(HDRS) radius.c spf.o spf.so: $(HDRS) spf.h spf.c dkim.o: diff --git a/src/src/miscmods/pam.c b/src/src/miscmods/pam.c new file mode 100644 index 000000000..1f1b2e2eb --- /dev/null +++ b/src/src/miscmods/pam.c @@ -0,0 +1,225 @@ +/************************************************* +* Exim - an Internet mail transport agent * +*************************************************/ + +/* Copyright (c) The Exim Maintainers 2020 - 2024 */ +/* 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 */ + +#include "../exim.h" + +/* This module contains functions that call the PAM authentication mechanism +defined by Sun for Solaris and also available for Linux and other OS. + +We can't just compile this code and allow the library mechanism to omit the +functions if they are not wanted, because we need to have the PAM headers +available for compiling. Therefore, compile these functions only if SUPPORT_PAM +is defined. However, some compilers don't like compiling empty modules, so keep +them happy with a dummy when skipping the rest. Make it reference itself to +stop picky compilers complaining that it is unused, and put in a dummy argument +to stop even pickier compilers complaining about infinite loops. +Then use a mutually-recursive pair as gcc is just getting stupid. */ + +#ifndef SUPPORT_PAM +static void dummy(int x); +static void dummy2(int x) { dummy(x-1); } +static void dummy(int x) { dummy2(x-1); } +#else /* SUPPORT_PAM */ + +#ifdef PAM_H_IN_PAM +# include +#else +# include +#endif + +/* According to the specification, it should be possible to have an application +data pointer passed to the conversation function. However, I was unable to get +this to work on Solaris 2.6, so static variables are used instead. */ + +static int pam_conv_had_error; +static const uschar *pam_args; +static BOOL pam_arg_ended; + + + +/************************************************* +* PAM conversation function * +*************************************************/ + +/* This function is passed to the PAM authentication function, and it calls it +back when it wants data from the client. The string list is in pam_args. When +we reach the end, we pass back an empty string once. If this function is called +again, it will give an error response. This is protection against something +crazy happening. + +Arguments: + num_msg number of messages associated with the call + msg points to an array of length num_msg of pam_message structures + resp set to point to the response block, which has to be got by + this function + appdata_ptr the application data pointer - not used because in Solaris + 2.6 it always arrived in pam_converse() as NULL + +Returns: a PAM return code +*/ + +static int +pam_converse (int num_msg, PAM_CONVERSE_ARG2_TYPE **msg, + struct pam_response **resp, void *appdata_ptr) +{ +int sep = 0; +struct pam_response *reply; + +/* It seems that PAM frees reply[] */ + +if ( pam_arg_ended + || !(reply = malloc(sizeof(struct pam_response) * num_msg))) + return PAM_CONV_ERR; + +for (int i = 0; i < num_msg; i++) + { + uschar *arg; + switch (msg[i]->msg_style) + { + case PAM_PROMPT_ECHO_ON: + case PAM_PROMPT_ECHO_OFF: + if (!(arg = string_nextinlist(&pam_args, &sep, NULL, 0))) + { + arg = US""; + pam_arg_ended = TRUE; + } + reply[i].resp = strdup(CCS arg); /* Use libc malloc, PAM frees resp directly*/ + reply[i].resp_retcode = PAM_SUCCESS; + break; + + case PAM_TEXT_INFO: /* Just acknowledge messages */ + case PAM_ERROR_MSG: + reply[i].resp_retcode = PAM_SUCCESS; + reply[i].resp = NULL; + break; + + default: /* Must be an error of some sort... */ + free(reply); + pam_conv_had_error = TRUE; + return PAM_CONV_ERR; + } + } + +*resp = reply; +return PAM_SUCCESS; +} + + + +/************************************************* +* Perform PAM authentication * +*************************************************/ + +/* This function calls the PAM authentication mechanism, passing over one or +more data strings. + +Arguments: + s a colon-separated list of strings + errptr where to point an error message + +Returns: OK if authentication succeeded + FAIL if authentication failed + ERROR some other error condition +*/ + +static int +auth_call_pam(const uschar *s, uschar **errptr) +{ +pam_handle_t *pamh = NULL; +struct pam_conv pamc; +int pam_error; +int sep = 0; +uschar *user; + +/* Set up the input data structure: the address of the conversation function, +and a pointer to application data, which we don't use because I couldn't get it +to work under Solaris 2.6 - it always arrived in pam_converse() as NULL. */ + +pamc.conv = pam_converse; +pamc.appdata_ptr = NULL; + +/* Initialize the static data - the current input data, the error flag, and the +flag for data end. */ + +pam_args = s; +pam_conv_had_error = FALSE; +pam_arg_ended = FALSE; + +/* The first string in the list is the user. If this is an empty string, we +fail. PAM doesn't support authentication with an empty user (it prompts for it, +causing a potential mis-interpretation). */ + +user = string_nextinlist(&pam_args, &sep, NULL, 0); +if (user == NULL || user[0] == 0) return FAIL; + +/* Start off PAM interaction */ + +DEBUG(D_auth) + debug_printf("Running PAM authentication for user \"%s\"\n", user); + +pam_error = pam_start ("exim", CS user, &pamc, &pamh); + +/* Do the authentication - the pam_authenticate() will call pam_converse() to +get the data it wants. After successful authentication we call pam_acct_mgmt() +to apply any other restrictions (e.g. only some times of day). */ + +if (pam_error == PAM_SUCCESS) + { + pam_error = pam_authenticate (pamh, PAM_SILENT); + if (pam_error == PAM_SUCCESS && !pam_conv_had_error) + pam_error = pam_acct_mgmt (pamh, PAM_SILENT); + } + +/* Finish the PAM interaction - this causes it to clean up store etc. Unclear +what should be passed as the second argument. */ + +pam_end(pamh, PAM_SUCCESS); + +/* Sort out the return code. If not success, set the error message. */ + +if (pam_error == PAM_SUCCESS) + { + DEBUG(D_auth) debug_printf("PAM success\n"); + return OK; + } + +*errptr = US pam_strerror(pamh, pam_error); +DEBUG(D_auth) debug_printf("PAM error: %s\n", *errptr); + +if (pam_error == PAM_USER_UNKNOWN || + pam_error == PAM_AUTH_ERR || + pam_error == PAM_ACCT_EXPIRED) + return FAIL; + +return ERROR; +} + + + +/******************************************************************************/ +/* Module API */ + +static void * pam_functions[] = { + [RADIUS_AUTH_CALL] = auth_call_pam, +}; + +misc_module_info rad_module_info = +{ + .name = US"pam", +# ifdef DYNLOOKUP + .dyn_magic = MISC_MODULE_MAGIC, +# endif + + .functions = pam_functions, + .functions_count = nelem(pam_functions), +}; + +#endif /* SUPPORT_PAM */ + +/* End of call_pam.c */ diff --git a/src/src/miscmods/pam_api.h b/src/src/miscmods/pam_api.h new file mode 100644 index 000000000..d83f27aa0 --- /dev/null +++ b/src/src/miscmods/pam_api.h @@ -0,0 +1,14 @@ +/************************************************* +* Exim - an Internet mail transport agent * +*************************************************/ + +/* Copyright (c) The Exim Maintainers 2024 */ +/* See the file NOTICE for conditions of use and distribution. */ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +/* API definitions for the pam module */ + + +/* Function table entry numbers */ + +#define PAM_AUTH_CALL 0 diff --git a/src/src/miscmods/radius_api.h b/src/src/miscmods/radius_api.h new file mode 100644 index 000000000..361a01ce3 --- /dev/null +++ b/src/src/miscmods/radius_api.h @@ -0,0 +1,14 @@ +/************************************************* +* Exim - an Internet mail transport agent * +*************************************************/ + +/* Copyright (c) The Exim Maintainers 2024 */ +/* See the file NOTICE for conditions of use and distribution. */ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +/* API definitions for the radius module */ + + +/* Function table entry numbers */ + +#define RADIUS_AUTH_CALL 0