libfuzzer clone compiler wrapper

.gitignore

@@ -1,4 +1,8 @@
 target
 Cargo.lock
 
+*.o
+*.a
+*.so
+
 .vscode

fuzzers/libfuzzer/Cargo.toml

@@ -7,4 +7,7 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-afl = { path = "../../../" }
+afl = { path = "../../" }
+
+[lib]
+crate-type = ["staticlib", "cdylib"]

fuzzers/libfuzzer/compiler

@@ -0,0 +1,84 @@
+#!/usr/bin/env python3
+
+import subprocess
+import sys
+import os
+
+script_dir = os.path.dirname(os.path.realpath(os.path.abspath(__file__)))
+
+is_cxx = "++" in sys.argv[0]
+
+def cc_exec(args):
+    if os.getenv("AFL_CC"):
+        cc_name = os.environ["AFL_CC"]
+    else:
+        cc_name = "clang"
+    if is_cxx:
+        if os.getenv("AFL_CXX"):
+            cc_name = os.environ["AFL_CXX"]
+        else:
+            cc_name = "clang++"
+    argv = [cc_name] + args
+    #print(" ".join(argv))
+    return subprocess.run(argv)
+
+
+def common_opts():
+    return [
+      "-g",
+    ]
+
+def cc_mode():
+    args = common_opts()
+    args += sys.argv[1:]
+    
+    if os.getenv("AFL_USE_ASAN"):
+        args += ["-fsanitize=address"]
+    if os.getenv("AFL_USE_MSAN"):
+        args += ["-fsanitize=memory"]
+    if os.getenv("AFL_USE_UBSAN"):
+        args += [
+                  "-fsanitize=undefined",
+                  "-fsanitize-undefined-trap-on-error",
+                  "-fno-sanitize-recover=all",
+                ]
+
+    return cc_exec(args)
+
+def ld_mode():
+    args = common_opts()
+    
+    args += sys.argv[1:]
+    args += [
+      os.path.join(script_dir, "runtime", "rt.o"),
+      os.path.join(script_dir, "target", "release", "liblibfuzzer.a"),
+    ]
+
+    if os.getenv("AFL_USE_ASAN"):
+        args += ["-fsanitize=address"]
+    if os.getenv("AFL_USE_MSAN"):
+        args += ["-fsanitize=memory"]
+    if os.getenv("AFL_USE_UBSAN"):
+        args += [
+                  "-fsanitize=undefined",
+                  "-fsanitize-undefined-trap-on-error",
+                  "-fno-sanitize-recover=all",
+                ]
+
+    args += ["-pthread", "-ldl"] # for Rust
+
+    return cc_exec(args)
+
+def is_ld_mode():
+    return not ("--version" in sys.argv or "--target-help" in sys.argv or
+                "-c" in sys.argv or "-E" in sys.argv or "-S" in sys.argv or
+                "-shared" in sys.argv)
+
+#print("\x1b[0;36m" + os.path.basename(sys.argv[0]) + " 1.0a\x1b[0m by <andreafioraldi@gmail.com>")
+
+if len(sys.argv) <= 1:
+  cc_exec(sys.argv[1:])
+elif is_ld_mode():
+    ld_mode()
+else:
+    cc_mode()

fuzzers/libfuzzer/runtime/Makefile

@@ -0,0 +1,10 @@
+CC ?= clang
+
+all: rt.o
+
+rt.o: rt.c
+	$(CC) -c rt.c
+
+clean:
+	rm -f rt.o
+

fuzzers/libfuzzer/runtime/rt.c

@@ -0,0 +1,15 @@
+
+
+__attribute__((weak)) int LLVMFuzzerInitialize(int *argc, char ***argv);
+
+void afl_libfuzzer_main();
+
+int main(int argc, char** argv) {
+
+  if (LLVMFuzzerInitialize)
+    LLVMFuzzerInitialize(&argc, &argv);
+  
+  afl_libfuzzer_main();
+  return 0;
+
+}

fuzzers/libfuzzer/src/lib.rs

@@ -5,17 +5,24 @@ use afl::engines::{DefaultEngine, DefaultState, Engine};
 use afl::executors::inmemory::InMemoryExecutor;
 use afl::executors::{Executor, ExitKind};
 use afl::inputs::bytes::BytesInput;
-use afl::mutators::scheduled::{
-    mutation_bitflip, ComposedByMutations, DefaultScheduledMutator,
-};
+use afl::mutators::scheduled::{mutation_bitflip, ComposedByMutations, DefaultScheduledMutator};
 use afl::stages::mutational::DefaultMutationalStage;
 use afl::utils::DefaultRand;
 
-fn harness<I>(_executor: &dyn Executor<I>, _buf: &[u8]) -> ExitKind {
+extern "C" {
+    /// int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)
+    fn LLVMFuzzerTestOneInput(data: *const u8, size: usize) -> i32;
+}
+
+fn harness<I>(_executor: &dyn Executor<I>, buf: &[u8]) -> ExitKind {
+    unsafe {
+        LLVMFuzzerTestOneInput(buf.as_ptr(), buf.len());
+    }
     ExitKind::Ok
 }
 
-pub fn main() {
+#[no_mangle]
+pub extern "C" fn afl_libfuzzer_main() {
     let rand = DefaultRand::new(0).into();
 
     let mut corpus = InMemoryCorpus::<BytesInput, _>::new(&rand);
@@ -40,4 +47,3 @@ pub fn main() {
     }
     println!("OK");
 }
-

fuzzers/libfuzzer/test/test.c

@@ -0,0 +1,45 @@
+#include <stdio.h>
+#include <stdint.h>
+
+// gcc -shared -o libdemo.so demo-so.c -w
+int target_func(char *buf, int size) {
+
+  printf("buffer:%p, size:%p\n", buf, size);
+  switch (buf[0]) {
+
+    case 1:
+      puts("222");
+      if (buf[1] == '\x44') {
+
+        puts("null ptr deference");
+        *(char *)(0) = 1;
+
+      }
+
+      break;
+    case 0xff:
+      if (buf[2] == '\xff') {
+
+        if (buf[1] == '\x44') {
+
+          puts("crash....");
+          *(char *)(0xdeadbeef) = 1;
+
+        }
+
+      }
+
+      break;
+    default:
+      puts("default action");
+      break;
+
+  }
+
+  return 1;
+
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  return target_func(Data, Size);
+}