executor: better support for globs

[keddad]

• Linux executor now mounts /syz-inputs folder to sandbox, so user can pass their own files for fuzzing with globs. Folder is mounted as RO, so this shouldn't make sandoxing less effective. (See https://groups.google.com/g/syzkaller/c/U-DISFjKLzg for specific usecase)

• Timeouts for globs are disabled. They can be quite slow (with default settings, in my tests, globs started timing out on thousands of files), and right now, if glob resolution timeouts, nothing happens. If you are running debug, you can see the timeout error, but in any case, it is ignored and fuzzer runs with less inputs then user expected without any notification. I think that it is reasonable to wait for those longer then default program timeout.

[dvyukov]

What motivated you to go with this approach rather than the second one I suggested?

Even better: minimize and supply the binaries as seeds for the fuzzer,
then it will even be able to mutate them as well.

[keddad]

I didn't want to use syzkaller's mutator here. I want to do some testing of ELF processing in both kernel and userspace applications, so instead I wanted to generate fuzzing artifacts with an external tool (Melkor) and then use those as-is with Syzkaller, as well as some other tools.

[dvyukov]

CI complains on some non-formatted source files:

diff --git a/executor/common.h b/executor/common.h
index faa7e3f..e7e02ff 100644
--- a/executor/common.h
+++ b/executor/common.h
@@ -700,7 +700,7 @@ static void loop(void)
 			uint64 min_timeout_ms = program_timeout_ms * 3 / 5;
 			uint64 inactive_timeout_ms = syscall_timeout_ms * 20;
 			uint64 glob_timeout_ms = program_timeout_ms * 120;
-			
+
 			uint64 now = current_time_ms();
 			uint32 now_executed = output_data->completed.load(std::memory_order_relaxed);
 			if (executed_calls != now_executed) {
executor/common.h:1:1: The file is not formatted/regenerated. Run 'make generate' and include it into the commit.
Error: The file is not formatted/regenerated. Run 'make generate' and include it into the commit.

This needs to be fixed before we can merge this.

[keddad]

Looks like I missed some whitespace differences. Should be fixed now, sorry.