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← Dokumentationsindex · ← NeverC-Projekt

NeverC DynCode-Compiler

Kompiliert C-Quellcode direkt in positionsunabhängigen, relocationsfreien, datensektionslosen flachen Binär-DynCode.

Anleitungen


Kernziele

  1. Normales C schreiben — keine dyncode-spezifischen Tricks.
  2. Vollautomatische Pipelinestatic int counter = 0, const char s[] = "...", Rekursion, write/exit/read/... und große Konstantenarrays werden intern ohne Änderungen am Benutzercode verarbeitet.
  3. Keine externen Abhängigkeiten — die Ausgabe .bin ist reiner Instruktionsstrom ohne dyld, libSystem oder Datensektion.
  4. CLI-Optionen per TableGen — jede -fdyncode-* in neverc/include/neverc/Invoke/Options.td.h (kein Hardcoding). Tippfehler → did-you-mean ; --help listet alle Optionen.
  5. Ausgabe-Constraints prüfbar-fdyncode-bad-bytes= / -fdyncode-bad-byte-profile= scannen die finale .bin nach post-extract und lehnen bei verbotenen Bytes ab (Offset, Byte, Kontext).
  6. Plattformübergreifende einzelne Pipeline — gesteuert durch TargetDesc. Gleiche C-Quelle für macOS / Linux / Android / Windows. Neue Plattform = eine Tabellenzeile + ein Extraktor, nicht fünf Pass-Sätze.

Unterstützte Ziele

Triple Format User-Mode-Syscall Ring-0-Resolver Status
arm64-apple-macos* Mach-O svc #0x80 (Darwin BSD) DarwinXNUKextShim Nativer Loader Round-Trip + Kernel-Resolver abgedeckt
x86_64-apple-macos* Mach-O syscall (BSD-Maske 0x2000000) DarwinXNUKextShim Kompilieren + Extraktion OK; x86_64 __text ohne Reloc-Erwartung
aarch64-linux-gnu ELF svc #0 (x8 = nr) LinuxKallsymsShim Kompilieren + Extraktion + Kernel-Resolver OK
x86_64-linux-gnu ELF syscall (rax = nr) LinuxKallsymsShim Kompilieren + Extraktion + Kernel-Resolver OK
aarch64-linux-android* ELF Wie Linux arm64 LinuxKallsymsShim (GKI) Kompilieren + Extraktion OK
x86_64-linux-android* ELF Wie Linux x86_64 LinuxKallsymsShim (GKI) Kompilieren + Extraktion OK
aarch64-pc-windows-msvc PE/COFF PEB-Walk (ldr xN, [x18, #0x60]) WindowsKernelResolverShim User-Mode PEB-Byte 32 40 f9 validiert; Ring-0 nutzt Loader-Resolver
x86_64-pc-windows-msvc PE/COFF PEB-Modul-Walk + PE-Exporttabelle WindowsKernelResolverShim User-Mode = vollständiger IR-PEB-Walk; Ring-0 nutzt PEB nicht erneut

Alle acht (OS, arch)-Triples nutzen dieselbe Pass-Menge. Unterschiede in TargetDesc.cpp und drei Extraktor-Zweigen. Neue Plattform = eine Zeile + ein Case pro Extraktor. ExecutionLevel orthogonal: User → Syscall/PEB ; Kernel deaktiviert beides und injiziert KernelImportPass für extern-Aufrufe über Resolver-Shims. Siehe kernel-mode-dyncode.md.


Schnellstart

# Always pass -target — output triple is independent of the compiler host.

# 1) Pure computation dyncode — no system calls
neverc -fdyncode -target arm64-apple-macos add.c -o add.bin

# 2) Darwin hello world — write/exit → svc #0x80
neverc -fdyncode -target arm64-apple-macos -mdyncode-syscall hello.c -o hello.bin

# 3) Linux arm64: svc #0 + x8=nr
neverc -fdyncode -target aarch64-linux-gnu -mdyncode-syscall \
       hello.c -o hello_linux_arm64.bin

# 4) Linux x86_64: syscall + rax=nr
neverc -fdyncode -target x86_64-linux-gnu -mdyncode-syscall \
       hello.c -o hello_linux_x64.bin

# 5) Windows x86_64 (PEB walk for API calls)
neverc -fdyncode -target x86_64-pc-windows-msvc \
       -mdyncode-win-peb-import win.c -o win.bin

# 6) Custom entry symbol
neverc -fdyncode -target arm64-apple-macos -fdyncode-entry=dyncode_main kernel.c -o k.bin

# 7) Keep intermediate object for audit (otool / llvm-objdump / dumpbin)
neverc -fdyncode -target arm64-apple-macos -fdyncode-keep-obj=/tmp/dump.obj x.c -o x.bin

# 8) Reject forbidden bytes in final .bin
neverc -fdyncode -target arm64-apple-macos -fdyncode-bad-bytes=00,0a,0d x.c -o x.bin

# 9) Built-in bad-byte profile (same as forbidding 00/0a/0d)
neverc -fdyncode -target arm64-apple-macos -fdyncode-bad-byte-profile=http-newline x.c -o x.bin

# 10) Run on macOS (platform-specific loader)
./loader_arm64_macos add.bin 3 4   # exit code = 7

# 11) Verbose extractor summary
neverc -v -fdyncode -target arm64-apple-macos fib.c -o fib.bin
#   dyncode-extractor: wrote 64 bytes to 'fib.bin'
#   dyncode-extractor: target   = arm64-apple-macos (Mach-O)
#   dyncode-extractor: entry symbol = _main
#   dyncode-extractor: patched 1 BRANCH26, 0 PAGE21, 0 PAGEOFF12 intra-section reloc(s)

CLI-Optionen (alle in Options.td.h)

Option Beschreibung
-fdyncode DynCode-Kompilierungsmodus aktivieren.
-fno-dyncode Vorheriges -fdyncode aufheben.
-fdyncode-all-blr Aggressiv: direkte Aufrufe zu blr xN / call *rax indirektisieren, alle relativen Branch-Relocs entfernen. Normal nicht nötig.
-mdyncode-syscall Syscall-Stubs explizit (Standard unter -fdyncode für Darwin/Linux/Android; Absicht/Skript-Kompat).
-mdyncode-libsystem Darwin-Legacy-Alias für -mdyncode-syscall.
-mdyncode-win-peb-import Windows-PEB-Import explizit (Standard mit -fdyncode + Windows-Triple).
-fdyncode-keep-obj=<path> Zwischenobjekt nach <path> kopieren für natives Disassembler-Audit.
-fdyncode-entry=<name> Standard-Einstieg überschreiben (main, _main, dyncode_entry, _dyncode_entry).
-fdyncode-bad-bytes=<hex-list> Verbotene Bytes (kommagetrennt). Scan der finalen .bin nach post-extract; bei Treffer kein File.
-fdyncode-bad-byte-profile=<name> Profile: null, c-string, http-newline, line, whitespace, ascii-control. Mit -fdyncode-bad-bytes= kombinierbar.
-fdyncode-obfuscate=<spec> An IR-Level-Plugin-Interposes über die Plugin-API. No-op ohne geladenes Plugin. Siehe ir-pass-design.md §9 — Obfuscation Interposes.
-fdyncode-mir-obfuscate=<spec> An MIR-Level-Interposes (RunBeforePreEmit / RunAfterPreEmit). Fallback -fdyncode-obfuscate=. Siehe mir-pass-design.md §3 — User Obfuscation Interposes.

Architekturüberblick

Die Pipeline teilt sich in zielunabhängige IR-Passes + zielspezifische Extraktoren:

flowchart TD
    Driver["neverc -fdyncode · OptTable + Options.td.h"]
    Frontend["C23 Frontend · PIC default"]
    Driver -->|describeTriple| Frontend
    Frontend -->|LLVM IR| ZRP

    subgraph IR["Target-Independent IR Passes"]
        direction TB
        ZRP["① ZeroRelocPass — Prep\ninternal + always_inline\nreject ctors / thread_local / extern_weak"]
        IBP["② IndirectBrPass\ncomputed-goto → switch"]
        SSP["③ SyscallStubPass\nlibc → svc #0x80 / svc #0 / syscall"]
        WPP["④ WinPEBImportPass\nextern Win32 API → PEB-walk thunk"]
        MIP["⑤ MemIntrinPass\nmemcpy/memset/str* → byte-loop"]
        CRP["⑥ CompilerRtPass\ni128 div/mod → inline long-division"]
        D2T1["⑦ Data2TextPass — Phase 1\nconst GV → stack stores"]
        ZRP --> IBP --> SSP --> WPP --> MIP --> CRP --> D2T1
    end

    Backend["AArch64 / X86 Backend\nSROA · InstCombine · AlwaysInliner · SLP"]
    D2T1 --> Backend

    Backend --> D2T2
    subgraph Post["Post-Backend IR"]
        direction TB
        D2T2["⑧ Data2TextPass — Phase 2\nvector const split"]
        ZRS["⑨ ZeroRelocPass — Stackify\nglobals → entry alloca"]
        ABP["⑩ AllBlrPass (optional)\ndirect call → indirect call"]
        D2T2 --> ZRS --> ABP
    end

    Codegen["Codegen · IR → MIR → Register Allocation"]
    ABP --> Codegen

    Codegen --> MH1
    subgraph MIR["MIR Layer"]
        direction TB
        MH1["⑪ RunBeforePreEmit interpose"]
        MIRP["⑫ DynCodeMIRPrepPass\nstrip CFI / EH_LABEL / XRay / StackMap"]
        MH2["⑬ RunAfterPreEmit interpose\ninstruction-level obfuscation entry"]
        MH1 --> MIRP --> MH2
    end

    MH2 -->|"Mach-O / ELF / COFF .o"| Extractor

    subgraph Extract["Extractor Layer"]
        Extractor["DynCodeExtractor\nMachO · ELF · COFF\npatch intra-.text relocs\nreject external reloc / data section\nbad-byte audit"]
    end

    Extractor --> Output(["flat .bin dyncode"])
Loading

Tabellengesteuerte Plattformunterschiede

neverc/include/neverc/DynCode/Pipeline/TargetDesc.h definiert TargetDesc pro (OS, arch):

  • TextSectionName: Mach-O __text / ELF .text / COFF .text
  • SyscallABI: enum value (DarwinSvc80 / LinuxSvc0 / LinuxSyscall / WindowsPEB / None)
  • AsmTemplate: svc #0x80 / svc #0 / syscall
  • SyscallNumberReg: x16 / x8 / rax
  • SyscallRetReg: x0 / rax
  • ArgRegs: ordered list of platform ABI argument registers + count
  • TCBReadAsm / TCBReadConstraint: inline-asm single-instruction template for reading TEB/PEB pointer (Windows x86_64 = movq %gs:0x60, $0, Windows arm64 = ldr $0, [x18, #0x60]). WinPEBImportPass reads directly from the table.
  • DriverInjectFlags: platform-specific driver flags as a null-terminated static array (x86_64 Unix gets -fpic -mcmodel=small; Windows gets -mno-stack-arg-probe / /GS-). perTargetInjectFlags reads from the table.

SyscallStubPass und WinPEBImportPass erzeugen InlineAsm aus TargetDesc. Das Backend nutzt TableGen-Muster. Neues Ziel = eine Zeile in describeTriple und ein Case pro Extraktor.

Extraktorschicht

Format Implementierung Patchbare Intra-Section-Relocations
Mach-O MachOExtractor.cpp arm64: ARM64_RELOC_BRANCH26 / PAGE21 / PAGEOFF12; x86_64: X86_64_RELOC_SIGNED / SIGNED_1/2/4 / BRANCH (intra-__text pcrel32); UNSIGNED / GOT_LOAD / GOT / SUBTRACTOR / TLV rejected
ELF ELFExtractor.cpp arm64: R_AARCH64_CALL26 / JUMP26 / ADR_PREL_PG_HI21(_NC) / ADD_ABS_LO12_NC / LDST{8,16,32,64,128}_ABS_LO12_NC / PREL32; x86_64: R_X86_64_PC32 / PLT32 (GOTPCREL rejected)
COFF COFFExtractor.cpp arm64: IMAGE_REL_ARM64_BRANCH26 / PAGEBASE_REL21 / PAGEOFFSET_12A / PAGEOFFSET_12L / REL32; x86_64: IMAGE_REL_AMD64_REL32 / REL32_[1-5]

Andere Typen oder Cross-Section-Relocations sind Hard-Fail mit Hinweisen (libc → Syscall-Stub / _Complex → manuelles Struct / Literal-Pool-Fallback usw.).


Matrix der Benutzercode-Fähigkeiten

Szenario Benutzercode Unterstützt Mechanismus
Integer arithmetic / bitwise int f(int a) { return a*3+1; } Ja Pure instruction stream
Recursion / loops int fib(int n) { ... } Ja static + always_inline
switch / case switch (op) { case 0: ... } Ja Driver injects -fno-jump-tables
Struct by-value passing struct Vec3 v = {...}; dot(v); Ja Stack-ified + always_inline
Floating-point double y = x * 3.14; Ja Data2Text rewrites ConstantFP to volatile-loaded bit pattern
Small constant arrays const int t[4] = {1,2,3,4}; Ja Data2Text stack-ifies
Large constant arrays (256B+) const unsigned char tbl[256] = {...} Ja Data2Text, no size limit
String literals const char s[] = "hi\n"; Ja Data2Text stack-ifies
memcpy / memset / memmove / memcmp memcpy(dst, src, n); Ja MemIntrinPass byte-loop wrappers
strlen / strcpy / strcmp / etc. strlen(buf); Ja MemIntrinPass byte-loop wrappers
__int128 division / modulo u128 q = a / b; Ja CompilerRtPass inline long-division
_Atomic / __atomic_* / __sync_* __atomic_fetch_add(&c, 1, ...) Ja Inline LDXR/STXR (arm64) / LOCK (x86_64)
__builtin_* family __builtin_popcount(x) Ja Backend single-instruction selection
VLA / flexible array / compound literal Normal C99/C11 Ja -fno-jump-tables + Data2Text
Mutable globals static int counter = 0; Ja ZeroReloc stack-ifies
libc write/exit write(1, s, 3); Yes (with -mdyncode-syscall) Syscall wrapper
POSIX includes #include <unistd.h> Yes (dyncode mode auto-switches to shim) Driver injects __NEVERC_DYNCODE__
Win32 API WriteFile(h, buf, n, &w, 0); Yes (with -mdyncode-win-peb-import) PEB-walk thunk
Windows SDK includes #include <windows.h> Yes (dyncode mode auto-switches to shim) Lightweight shim headers
Custom entry name int dyncode_main(...) Yes (with -fdyncode-entry=...) Driver pass-through
Global constructors __attribute__((constructor)) Nein No runtime to trigger them
TLS / thread_local thread_local int x; Auto-demoted to static ZeroRelocPass.Prep silently demotes
C++ / ObjC Nein Projektumfang nur C

Verzeichnisstruktur

neverc/
├── include/neverc/Invoke/Options.td.h           # -fdyncode-* TableGen definitions
├── include/neverc/DynCode/                  # Headers (organized by subsystem)
│   ├── Pipeline/                              # Pipeline / driver integration
│   │   ├── Pipeline.h                         # IR + MIR interpose registration
│   │   ├── DriverIntegration.h
│   │   ├── TargetDesc.h                       # Platform table / descriptors
│   │   ├── DynCodeOptions.h                 # Cross-subsystem config
│   │   ├── Diagnostics.h                      # Cross-subsystem diagnostics
│   │   └── SymbolNames.h                      # Cross-subsystem symbol utilities
│   ├── Extractor/
│   │   └── DynCodeExtractor.h
│   ├── IR/                                    # IR-level passes and ABIs
│   │   ├── ZeroRelocPass.h / ZeroRelocABI.h
│   │   ├── Data2TextPass.h / Data2TextABI.h
│   │   ├── AllBlrPass.h / IndirectBrPass.h
│   │   ├── MemIntrinPass.h                    # memcpy/memset/str* inlining
│   │   ├── StringRuntimePass.h / StringRuntimeABI.h
│   │   ├── HeapArenaPass.h                    # malloc/free → arena + OS fallback
│   │   ├── MmapABI.h                          # Gemeinsame mmap-Konstanten (prot/flags)
│   │   ├── DynCodeIRHelpers.h               # Gemeinsame IR-Hilfsfunktionen (getSizeType usw.)
│   │   ├── ExternRewriter.h                   # Extern function rewrite utilities
│   │   └── CompilerRtPass.h                   # __int128 division inline
│   ├── MIR/
│   │   └── MIRPrepPass.h                      # Catch-all MachineFunctionPass
│   ├── Import/                                # User-mode + kernel-mode import resolution
│   │   ├── SyscallStub.h / SyscallTables.h
│   │   ├── WinPEBImport.h / WinImportTables.h
│   │   ├── KernelImportPass.h / KernelImportABI.h
│   │   └── PtrCacheHelpers.h                  # Shared address cache encryption helpers
│   └── Tables/                                # User-extensible .def tables
├── lib/DynCode/                             # Implementation (mirrors header structure)
│   ├── Pipeline/ Extractor/ IR/ MIR/ Import/
└── lib/Invoke/Core/Driver.cpp

tests/neverc/                                   # Tests (GTest)
├── DynCodeTests.cpp                         # Core dyncode round-trip tests
├── DynCodeStressTests.cpp                   # Stress tests (VLA, __sync_*, __int128, etc.)
├── DynCodeCrossTargetTests.cpp              # Cross-target compile-only smoke tests
├── dyncode/
│   ├── loader_arm64_macos.c / loader_linux.c / loader_windows.c
│   └── test_dyncode_*.c

docs/dyncode-compiler/
├── README.md                                  ← Englisch
├── README.de.md                               ← Deutsch
├── arm64-assembly-tutorial/README.md
├── cross-platform-architecture/README.md
├── ir-pass-design/README.md
├── kernel-mode-dyncode/README.md
├── mir-pass-design/README.md
├── pipeline-and-pic/README.md
├── platform-extension-guide/README.md
├── progress/README.md
└── roadmap/README.md

Voraussetzungen (plattformübergreifend)

  1. Ladeadresse 4 KB ausgerichtet — natürliches Verhalten von mmap / VirtualAlloc ; Loader erfüllen dies bereits.
  2. Aufrufkonventionen folgen der nativen ABI des Ziel-OS:
    • Darwin / Linux / Android: System V AMD64 or AAPCS64
    • Windows: Win64 (rcx/rdx/r8/r9)
  3. Loader verantwortlich für i-cache-Flush (arm64) / FlushInstructionCache (Windows).

Obfuskation & Plugin-Erweiterung

Die DynCode-Pipeline stellt selbst nur sicher, dass „der Code korrekt läuft“. Obfuskation, Polymorphismus, gestufte Encoder und ähnliche Features der Strategieebene sind absichtlich nicht eingebaut — sie werden von Out-of-Tree-Plugins über die Plugin-API bereitgestellt.

Die Pipeline exponiert 11 Interpose-Punkte auf drei Ebenen, alle über die C-Plugin-API (NEVERC_INTERPOSE_SC_*) zugänglich:

IR-Ebene (6 Interposes):

  • NEVERC_INTERPOSE_SC_BEFORE_PREP — Before any dyncode pass
  • NEVERC_INTERPOSE_SC_AFTER_PREP — Linkage unified (internal + always_inline)
  • NEVERC_INTERPOSE_SC_BEFORE_INLINING — Last chance before AlwaysInliner
  • NEVERC_INTERPOSE_SC_AFTER_INLINING — IR fully compressed into one large function
  • NEVERC_INTERPOSE_SC_AFTER_STACKIFY — Final IR shape, next step is codegen
  • NEVERC_INTERPOSE_SC_AFTER_FINAL_IR — After AllBlrPass, the true last IR interpose

MIR-Ebene (3 Interposes):

  • NEVERC_INTERPOSE_SC_BEFORE_PREEMIT — Registers allocated, CFI/EH pseudos still present
  • NEVERC_INTERPOSE_SC_AFTER_PREEMITBuilt-in MIRPrepPass has stripped pseudos, closest to the byte form AsmPrinter will see; ideal for instruction-level obfuscation/register renaming
  • NEVERC_INTERPOSE_SC_AFTER_FINAL_MIR — True last MIR interpose, after LLVM addPreEmitPass2(), just before AsmPrinter

Byte-Stream-Ebene (2 Interposes):

  • NEVERC_INTERPOSE_SC_POST_EXTRACT — After extractor completes intra-text relocation patching and data-section audit; before .bin is written. Use for whole-payload encryption, junk byte insertion, or custom headers.
  • NEVERC_INTERPOSE_SC_POST_FINALIZE — After all finalize steps; NeverC performs no further auditing.

Siehe die Plugin-API-Dokumentation für die vollständige Interpose-Liste, Pass-Registrierung und Codebeispiele.


Aktuelle Einschränkungen

  • Supports 8 (OS, arch) combinations (see matrix above). Other triples (RISC-V, PowerPC, 32-bit x86, big-endian ARM, etc.) are rejected at describeTriple() with the full supported set listed as a hint. Each (OS, arch) row has independent User / Kernel contexts, yielding 16 (OS, arch, level) variants.
  • Windows PEB walk is fully implemented with multi-DLL dispatch. __neverc_win_resolve accepts (dll_hash, api_hash) pairs. The current whitelist covers kernel32.dll (~125 APIs), ntdll.dll (~26), user32.dll (~13), ws2_32.dll (~23), advapi32.dll (~16), shell32.dll (~6). Adding an API = one row in Tables/Win32Apis.def + one declaration in lib/Headers/windows.h.
  • External function whitelist only covers Darwin BSD / Linux / Android common syscalls (~80+) + Win32 APIs (~210). stdio and similar runtime-heavy interfaces are not included — dyncode cannot embed the full stdio state machine.
  • Kein C++ / ObjC / CUDA — NeverC ist bewusst nur C.