Remove is_main_fuzzer file, respect the AFL deputee main node

logistic/packer.go

@@ -33,7 +33,6 @@ func PackFuzzers(fuzzers []string, fuzzerDirectory string) ([]byte, error) {
 	// Essentially we want to pack three things from each targeted fuzzer:
 	// - the fuzz_bitmap file
 	// - the fuzzer_stats file
-	// - the is_main_fuzzer file if present
 	// - the queue/ directory - but avoiding duplicates
 	var pkgCont []string // list of queue files already present in the archive
 	for _, fuzzer := range fuzzers {
@@ -42,9 +41,8 @@ func PackFuzzers(fuzzers []string, fuzzerDirectory string) ([]byte, error) {
 		relFuzzerPath := strings.TrimPrefix(fuzzer, fuzzerDirectory)
 
 		// Read-n-Pack™
-		packSingleFile(tarWriter, absFuzzerPath, relFuzzerPath, "fuzz_bitmap", false)
-		packSingleFile(tarWriter, absFuzzerPath, relFuzzerPath, "fuzzer_stats", false)
-		packSingleFile(tarWriter, absFuzzerPath, relFuzzerPath, "is_main_fuzzer", true)
+		packSingleFile(tarWriter, absFuzzerPath, relFuzzerPath, "fuzz_bitmap")
+		packSingleFile(tarWriter, absFuzzerPath, relFuzzerPath, "fuzzer_stats")
 		packQueueFiles(tarWriter, absFuzzerPath, relFuzzerPath, &pkgCont)
 	}
 
@@ -70,15 +68,12 @@ func PackFuzzers(fuzzers []string, fuzzerDirectory string) ([]byte, error) {
 // fuzzerDirectory is the base directory, e.g. /project/fuzzers/
 // fuzzer is the name of the fuzzer itself, e.g. main-fuzzer-01
 // filename is the name of the file you want to pack, e.g. fuzzer_stats
-// ignoreNotFound is just used for files which may not be present in all fuzzer directories, like is_main_fuzzer
-func packSingleFile(tarWriter *tar.Writer, absPath string, relPath string, fileName string, ignoreNotFound bool) {
+func packSingleFile(tarWriter *tar.Writer, absPath string, relPath string, fileName string) {
 	// Read file
 	readPath := fmt.Sprintf("%s%c%s%c%s", absPath, os.PathSeparator, relPath, os.PathSeparator, fileName)
 	contents, readErr := ioutil.ReadFile(readPath)
 	if readErr != nil {
-		if !ignoreNotFound {
 		log.Printf("Failed to read file %s: %s", readPath, readErr)
-		}
 		return
 	}
 
@@ -127,7 +122,7 @@ func packQueueFiles(tarWriter *tar.Writer, absPath string, relPath string, pkgCo
 		}
 
 		// Pack into the archive
-		packSingleFile(tarWriter, absPath, relPath, fmt.Sprintf("queue%c%s", os.PathSeparator, f.Name()), false)
+		packSingleFile(tarWriter, absPath, relPath, fmt.Sprintf("queue%c%s", os.PathSeparator, f.Name()))
 
 		if noDuplicates {
 			// Append added file name to the list of things included in the package

watchdog/watchdog.go

@@ -27,7 +27,7 @@ func WatchFuzzers(outputDirectory string) {
 	// Loop forever
 	for {
 		// Pack important parts of the fuzzers into an archive
-		packedFuzzers, packerErr := logistic.PackFuzzers(getTargetFuzzers(outputDirectory), outputDirectory)
+		packedFuzzers, packerErr := logistic.PackFuzzers(getTargetFuzzer(outputDirectory), outputDirectory)
 		if packerErr != nil {
 			log.Printf("Failed to pack fuzzer: %s", packerErr)
 			continue
@@ -43,15 +43,15 @@ func WatchFuzzers(outputDirectory string) {
 
 // Searches in the specified output directory for fuzzers which we want to pack.
 // Identifying the main fuzzer is done by searching for the file "is_main_node"
-// Identifying local secondary fuzzers is done by searching for a file which is not shared between nodes as it is not required for clusterized fuzzing: 'cmdline'.
-// Please note that this is not failsafe, e.g. if you already synced your fuzzers over a different tool or by hand before.
-//
-// - If we are running in main mode (--main), we want to share the main fuzzers' queue with the secondary nodes
-// - If we are not running in main mode, we want to share all of our fuzzers' queues with the main node
+// This relies on the "election process" done by secondary fuzzers if they don't find a local main node.
+// If that is detected, a secondary fuzzer becomes the main node in terms of syncing. That means we need to focus on
+// the main node even if there is no real main node running locally.
+// However it is important to avoid transmitting the is_main_node file - else, the secondaries will think that there is
+// a main node running locally. Skipping the is_main_node file means the other fuzzers (and especially the elected main
+// fuzzer) detect the transmitted fuzzer as a normal (and dead) secondary. ... blabla
 //
 // (see AFLplusplus/src/afl-fuzz.run.c:542)
-func getTargetFuzzers(outputDirectory string) []string {
-	if isMainNode {
+func getTargetFuzzer(outputDirectory string) []string {
 	// find main fuzzer directory - its the only one required by the secondaries
 
 	// List files (read: fuzzers) in output directory
@@ -84,36 +84,4 @@ func getTargetFuzzers(outputDirectory string) []string {
 	// Failed to find the main node - probably we are in --main mode by accident
 	log.Printf("Unable to find main node in %s - sure afl-transmit should run in --main mode?", outputDirectory)
 	return nil
-	} else {
-		// get all fuzzer directories which are locally available
-		var localFuzzers []string
-
-		// List files (read: fuzzers) in output directory
-		filesInDir, readErr := ioutil.ReadDir(outputDirectory)
-		if readErr != nil {
-			log.Printf("Failed to list directory content of %s: %s", outputDirectory, readErr)
-			return nil
-		}
-
-		// Walk over each fuzzer and search for 'cmdline' file
-		for _, f := range filesInDir {
-			// Get stat for maybe-existent file
-			cmdlinePath := fmt.Sprintf("%s%c%s%ccmdline", outputDirectory, os.PathSeparator, f.Name(), os.PathSeparator)
-			_, statErr := os.Stat(cmdlinePath)
-			if os.IsNotExist(statErr) {
-				// File does not exist. That's fine. Next.
-				continue
-			} else if statErr != nil {
-				// An error occurred. File is maybe in a Schrödinger state.
-				log.Printf("Unable to stat file %s: %s", cmdlinePath, statErr)
-				continue
-			}
-
-			// File exists, let's watch it
-			fullPath := fmt.Sprintf("%s%c%s", outputDirectory, os.PathSeparator, f.Name())
-			localFuzzers = append(localFuzzers, fullPath)
-		}
-
-		return localFuzzers
-	}
 }