From: Sam Hartman <hartmans@debian.org>
Date: Mon, 11 Sep 2023 14:00:42 -0600
Subject: _pam_include

Patch to implement an @include directive for use in pam.d config files.

Authors: Jan Christoph Nordholz <hesso@pool.math.tu-berlin.de>

Upstream status: not yet submitted
---
 libpam/pam_handlers.c | 36 ++++++++++++++++++++++++++++++++----
 1 file changed, 32 insertions(+), 4 deletions(-)

diff --git a/libpam/pam_handlers.c b/libpam/pam_handlers.c
index 1f1917b..c7045d2 100644
--- a/libpam/pam_handlers.c
+++ b/libpam/pam_handlers.c
@@ -123,6 +123,10 @@ static int _pam_parse_conf_file(pam_handle_t *pamh, FILE *f
 		    module_type = PAM_T_ACCT;
 		} else if (!strcasecmp("password", tok)) {
 		    module_type = PAM_T_PASS;
+		} else if (!strcasecmp("@include", tok)) {
+		    pam_include = 1;
+		    module_type = requested_module_type;
+		    goto parsing_done;
 		} else {
 		    /* Illegal module type */
 		    D(("_pam_init_handlers: bad module type: %s", tok));
@@ -193,8 +197,10 @@ static int _pam_parse_conf_file(pam_handle_t *pamh, FILE *f
 		_pam_set_default_control(actions, _PAM_ACTION_BAD);
 	    }
 
+parsing_done:
 	    tok = _pam_StrTok(NULL, " \n\t", &nexttok);
 	    if (pam_include) {
+		struct stat include_dir;
 		if (substack) {
 		    res = _pam_add_handler(pamh, PAM_HT_SUBSTACK, other,
 				stack_level, module_type, actions, tok,
@@ -205,13 +211,35 @@ static int _pam_parse_conf_file(pam_handle_t *pamh, FILE *f
 			return PAM_ABORT;
 		    }
 		}
-		if (_pam_load_conf_file(pamh, tok, this_service, module_type,
-		    stack_level + substack
+		if (tok[0] == '/') {
+		    if (_pam_load_conf_file(pamh, tok, this_service,
+		                            module_type, stack_level + substack
+#ifdef PAM_READ_BOTH_CONFS
+		                            , !other
+#endif /* PAM_READ_BOTH_CONFS */
+		       ) == PAM_SUCCESS)
+			continue;
+		}
+		else if (!stat(PAM_CONFIG_D, &include_dir)
+		         && S_ISDIR(include_dir.st_mode))
+		{
+		    char *include_file;
+		    if (asprintf (&include_file, PAM_CONFIG_DF, tok) < 0) {
+			pam_syslog(pamh, LOG_CRIT, "asprintf failed");
+			return PAM_ABORT;
+		    }
+		    if (_pam_load_conf_file(pamh, include_file, this_service,
+		                            module_type, stack_level + substack
 #ifdef PAM_READ_BOTH_CONFS
 					      , !other
 #endif /* PAM_READ_BOTH_CONFS */
-		    ) == PAM_SUCCESS)
-		    continue;
+		       ) == PAM_SUCCESS)
+		    {
+			free(include_file);
+			continue;
+		    }
+		    free(include_file);
+		}
 		_pam_set_default_control(actions, _PAM_ACTION_BAD);
 		mod_path = NULL;
 		handler_type = PAM_HT_MUST_FAIL;