From: Timo Sirainen <timo.sirainen@open-xchange.com>
Date: Mon, 9 May 2022 15:23:33 +0300
Subject: auth: Fix handling passdbs with identical driver/args but different
 mechanisms/username_filter

The passdb was wrongly deduplicated in this situation, causing wrong
mechanisms or username_filter setting to be used. This would be a rather
unlikely configuration though.

Fixed by moving mechanisms and username_filter from struct passdb_module
to struct auth_passdb, which is where they should have been in the first
place.
---
 src/auth/auth-request.c |  6 +++---
 src/auth/auth.c         | 18 ++++++++++++++++++
 src/auth/auth.h         |  5 +++++
 src/auth/passdb.c       | 15 ++-------------
 src/auth/passdb.h       |  4 ----
 5 files changed, 28 insertions(+), 20 deletions(-)

diff --git a/src/auth/auth-request.c b/src/auth/auth-request.c
index ee89e75..cd44cd4 100644
--- a/src/auth/auth-request.c
+++ b/src/auth/auth-request.c
@@ -553,8 +553,8 @@ auth_request_want_skip_passdb(struct auth_request *request,
 			      struct auth_passdb *passdb)
 {
 	/* if mechanism is not supported, skip */
-	const char *const *mechs = passdb->passdb->mechanisms;
-	const char *const *username_filter = passdb->passdb->username_filter;
+	const char *const *mechs = passdb->mechanisms;
+	const char *const *username_filter = passdb->username_filter;
 	const char *username;
 
 	username = request->fields.user;
@@ -567,7 +567,7 @@ auth_request_want_skip_passdb(struct auth_request *request,
 		return TRUE;
 	}
 
-	if (passdb->passdb->username_filter != NULL &&
+	if (passdb->username_filter != NULL &&
 	    !auth_request_username_accepted(username_filter, username)) {
 		auth_request_log_debug(request,
 				       request->mech != NULL ? AUTH_SUBSYS_MECH
diff --git a/src/auth/auth.c b/src/auth/auth.c
index 845c43c..a5a4c81 100644
--- a/src/auth/auth.c
+++ b/src/auth/auth.c
@@ -93,6 +93,24 @@ auth_passdb_preinit(struct auth *auth, const struct auth_passdb_settings *set,
 	auth_passdb->override_fields_tmpl =
 		passdb_template_build(auth->pool, set->override_fields);
 
+	if (*set->mechanisms == '\0') {
+		auth_passdb->mechanisms = NULL;
+	} else if (strcasecmp(set->mechanisms, "none") == 0) {
+		auth_passdb->mechanisms = (const char *const[]){ NULL };
+	} else {
+		auth_passdb->mechanisms =
+			(const char *const *)p_strsplit_spaces(auth->pool,
+				set->mechanisms, " ,");
+	}
+
+	if (*set->username_filter == '\0') {
+		auth_passdb->username_filter = NULL;
+	} else {
+		auth_passdb->username_filter =
+			(const char *const *)p_strsplit_spaces(auth->pool,
+				set->username_filter, " ,");
+	}
+
 	/* for backwards compatibility: */
 	if (set->pass)
 		auth_passdb->result_success = AUTH_DB_RULE_CONTINUE;
diff --git a/src/auth/auth.h b/src/auth/auth.h
index 3ca5a9b..6208e4d 100644
--- a/src/auth/auth.h
+++ b/src/auth/auth.h
@@ -41,6 +41,11 @@ struct auth_passdb {
 	struct passdb_template *default_fields_tmpl;
 	struct passdb_template *override_fields_tmpl;
 
+	/* Supported authentication mechanisms, NULL is all, {NULL} is none */
+	const char *const *mechanisms;
+	/* Username filter, NULL is no filter */
+	const char *const *username_filter;
+
 	enum auth_passdb_skip skip;
 	enum auth_db_rule result_success;
 	enum auth_db_rule result_failure;
diff --git a/src/auth/passdb.c b/src/auth/passdb.c
index 9bc2b87..d3c61cc 100644
--- a/src/auth/passdb.c
+++ b/src/auth/passdb.c
@@ -224,19 +224,8 @@ passdb_preinit(pool_t pool, const struct auth_passdb_settings *set)
 	passdb->id = ++auth_passdb_id;
 	passdb->iface = *iface;
 	passdb->args = p_strdup(pool, set->args);
-	if (*set->mechanisms == '\0') {
-		passdb->mechanisms = NULL;
-	} else if (strcasecmp(set->mechanisms, "none") == 0) {
-		passdb->mechanisms = (const char *const[]){NULL};
-	} else {
-		passdb->mechanisms = (const char* const*)p_strsplit_spaces(pool, set->mechanisms, " ,");
-	}
-
-	if (*set->username_filter == '\0') {
-		passdb->username_filter = NULL;
-	} else {
-		passdb->username_filter = (const char* const*)p_strsplit_spaces(pool, set->username_filter, " ,");
-	}
+	/* NOTE: if anything else than driver & args are added here,
+	   passdb_find() also needs to be updated. */
 	array_push_back(&passdb_modules, &passdb);
 	return passdb;
 }
diff --git a/src/auth/passdb.h b/src/auth/passdb.h
index b405aa7..8f50050 100644
--- a/src/auth/passdb.h
+++ b/src/auth/passdb.h
@@ -63,10 +63,6 @@ struct passdb_module {
 	/* Default password scheme for this module.
 	   If default_cache_key is set, must not be NULL. */
 	const char *default_pass_scheme;
-	/* Supported authentication mechanisms, NULL is all, [NULL] is none*/
-	const char *const *mechanisms;
-	/* Username filter, NULL is no filter */
-	const char *const *username_filter;
 
 	/* If blocking is set to TRUE, use child processes to access
 	   this passdb. */