[issue-328]: Add option to use clientid instead of username when running checks.

README.md

@@ -245,6 +245,19 @@ auth_opt_backends files, postgres, jwt
 
 Set all other plugin options below in the same file.
 
+#### Using clientid as username
+
+You may choose to override chedk against `username` to be done against `clientid` by setting this option:
+
+```
+auth_opt_use_clientid_as_username true
+```
+
+Notice this will effectively change `username` to be the same as `clientid` at the top level, so every check,
+including cached ones, will drop Mosquitto's passed `username` and use `clientid` instead.
+
+This option default to false if not given or anything but `true` is set to its value.
+
 #### Cache
 
 There are 2 types of caches supported: an in memory one using [go-cache](https://github.com/patrickmn/go-cache), or a Redis backed one.

cache/cache.go

@@ -182,7 +182,7 @@ func (s *goStore) CheckAuthRecord(ctx context.Context, username, password string
 	return s.checkRecord(ctx, record, expirationWithJitter(s.authExpiration, s.authJitter))
 }
 
-//CheckAclCache checks if the username/topic/clientid/acc mix is present in the cache. Return if it's present and, if so, if it was granted privileges.
+// CheckAclCache checks if the username/topic/clientid/acc mix is present in the cache. Return if it's present and, if so, if it was granted privileges.
 func (s *goStore) CheckACLRecord(ctx context.Context, username, topic, clientid string, acc int) (bool, bool) {
 	record := toACLRecord(username, topic, clientid, acc, s.h)
 	return s.checkRecord(ctx, record, expirationWithJitter(s.aclExpiration, s.aclJitter))
@@ -211,7 +211,7 @@ func (s *redisStore) CheckAuthRecord(ctx context.Context, username, password str
 	return s.checkRecord(ctx, record, s.authExpiration)
 }
 
-//CheckAclCache checks if the username/topic/clientid/acc mix is present in the cache. Return if it's present and, if so, if it was granted privileges.
+// CheckAclCache checks if the username/topic/clientid/acc mix is present in the cache. Return if it's present and, if so, if it was granted privileges.
 func (s *redisStore) CheckACLRecord(ctx context.Context, username, topic, clientid string, acc int) (bool, bool) {
 	record := toACLRecord(username, topic, clientid, acc, s.h)
 	return s.checkRecord(ctx, record, s.aclExpiration)
@@ -266,7 +266,7 @@ func (s *goStore) SetAuthRecord(ctx context.Context, username, password string,
 	return nil
 }
 
-//SetAclCache sets a mix, granted option and expiration time.
+// SetAclCache sets a mix, granted option and expiration time.
 func (s *goStore) SetACLRecord(ctx context.Context, username, topic, clientid string, acc int, granted string) error {
 	record := toACLRecord(username, topic, clientid, acc, s.h)
 	s.client.Set(record, granted, expirationWithJitter(s.aclExpiration, s.aclJitter))
@@ -280,7 +280,7 @@ func (s *redisStore) SetAuthRecord(ctx context.Context, username, password strin
 	return s.setRecord(ctx, record, granted, expirationWithJitter(s.authExpiration, s.authJitter))
 }
 
-//SetAclCache sets a mix, granted option and expiration time.
+// SetAclCache sets a mix, granted option and expiration time.
 func (s *redisStore) SetACLRecord(ctx context.Context, username, topic, clientid string, acc int, granted string) error {
 	record := toACLRecord(username, topic, clientid, acc, s.h)
 	return s.setRecord(ctx, record, granted, expirationWithJitter(s.aclExpiration, s.aclJitter))

go-auth.go

@@ -16,15 +16,16 @@ import (
 )
 
 type AuthPlugin struct {
-	backends   *bes.Backends
-	useCache   bool
-	logLevel   log.Level
-	logDest    string
-	logFile    string
-	ctx        context.Context
-	cache      cache.Store
-	hasher     hashing.HashComparer
-	retryCount int
+	backends              *bes.Backends
+	useCache              bool
+	logLevel              log.Level
+	logDest               string
+	logFile               string
+	ctx                   context.Context
+	cache                 cache.Store
+	hasher                hashing.HashComparer
+	retryCount            int
+	useClientidAsUsername bool
 }
 
 // errors to signal mosquitto
@@ -63,6 +64,13 @@ func AuthPluginInit(keys []*C.char, values []*C.char, authOptsNum int, version *
 		}
 	}
 
+	if useClientidAsUsername, ok := authOpts["use_clientid_as_username"]; ok && strings.Replace(useClientidAsUsername, " ", "", -1) == "true" {
+		log.Info("clientid will be used as username on checks")
+		authPlugin.useClientidAsUsername = true
+	} else {
+		authPlugin.useClientidAsUsername = false
+	}
+
 	//Check if log level is given. Set level if any valid option is given.
 	if logLevel, ok := authOpts["log_level"]; ok {
 		logLevel = strings.Replace(logLevel, " ", "", -1)
@@ -304,6 +312,9 @@ func authUnpwdCheck(username, password, clientid string) (bool, error) {
 	var cached bool
 	var granted bool
 	var err error
+
+	username = setUsername(username, clientid)
+
 	if authPlugin.useCache {
 		log.Debugf("checking auth cache for %s", username)
 		cached, granted = authPlugin.cache.CheckAuthRecord(authPlugin.ctx, username, password)
@@ -358,6 +369,9 @@ func authAclCheck(clientid, username, topic string, acc int) (bool, error) {
 	var cached bool
 	var granted bool
 	var err error
+
+	username = setUsername(username, clientid)
+
 	if authPlugin.useCache {
 		log.Debugf("checking acl cache for %s", username)
 		cached, granted = authPlugin.cache.CheckACLRecord(authPlugin.ctx, username, topic, clientid, acc)
@@ -401,4 +415,12 @@ func AuthPluginCleanup() {
 	authPlugin.backends.Halt()
 }
 
+func setUsername(username, clientid string) string {
+	if authPlugin.useClientidAsUsername {
+		return clientid
+	}
+
+	return username
+}
+
 func main() {}