rename allocator symbols to avoid conflict with mimalloc

Author: addisoncrump

libafl_libfuzzer/build.rs

@@ -69,20 +69,98 @@ fn main() {
     let mut lib_path = custom_lib_dir.join(std::env::var_os("TARGET").unwrap());
     lib_path.push("release");
 
-    #[cfg(all(feature = "embed-runtime", target_family = "unix"))]
-    {
-        // NOTE: lib, .a are added always on unix-like systems as described in:
-        // https://gist.github.com/novafacing/1389cbb2f0a362d7eb103e67b4468e2b
+    if cfg!(target_family = "unix") {
+        use std::path::Path;
+
+        lib_path.push("libafl_libfuzzer_runtime.a");
+        let target_libdir = Command::new("rustc")
+            .args(["--print", "target-libdir"])
+            .output()
+            .expect("Couldn't find rustc's target-libdir");
+        let target_libdir = String::from_utf8(target_libdir.stdout).unwrap();
+        let target_libdir = Path::new(target_libdir.trim());
+
+        let rust_lld = target_libdir.join("../bin/rust-lld");
+        let rust_ar = target_libdir.join("../bin/llvm-ar"); // NOTE: depends on llvm-tools
+        let rust_objcopy = target_libdir.join("../bin/llvm-objcopy"); // NOTE: depends on llvm-tools
+
+        let objfile_orig = custom_lib_dir.join("libFuzzer.o");
+        let objfile_dest = custom_lib_dir.join("libFuzzer-mimalloc.o");
+
+        let mut command = Command::new(rust_lld);
+        command
+            .args(["-flavor", "gnu"])
+            .arg("-r")
+            .arg("--whole-archive")
+            .arg(lib_path)
+            .args(["-o", objfile_orig.to_str().expect("Invalid path characters present in your current directory prevent us from linking to the runtime")]);
+
+        assert!(
+            !command.status().map(|s| !s.success()).unwrap_or(true),
+            "Couldn't link runtime crate! Do you have the llvm-tools component installed?"
+        );
+
+        let mut command = Command::new(rust_objcopy);
+        command
+            .args(["--redefine-sym", "__rust_alloc=__rust_alloc_mimalloc"])
+            .args(["--redefine-sym", "__rust_dealloc=__rust_dealloc_mimalloc"])
+            .args(["--redefine-sym", "__rust_realloc=__rust_realloc_mimalloc"])
+            .args([
+                "--redefine-sym",
+                "__rust_alloc_zeroed=__rust_alloc_zeroed_mimalloc",
+            ])
+            .args([
+                "--redefine-sym",
+                "__rust_alloc_error_handler=__rust_alloc_error_handler_mimalloc",
+            ])
+            .args([
+                "--redefine-sym",
+                "__rust_no_alloc_shim_is_unstable=__rust_no_alloc_shim_is_unstable_mimalloc",
+            ])
+            .args([
+                "--redefine-sym",
+                "__rust_alloc_error_handler_should_panic=__rust_alloc_error_handler_should_panic_mimalloc",
+            ])
+            .args([&objfile_orig, &objfile_dest]);
+
+        assert!(
+            !command.status().map(|s| !s.success()).unwrap_or(true),
+            "Couldn't rename allocators in the runtime crate! Do you have the llvm-tools component installed?"
+        );
+
+        let mut command = Command::new(rust_ar);
+        command
+            .arg("cr")
+            .arg(custom_lib_dir.join("libFuzzer.a"))
+            .arg(objfile_dest);
+
+        assert!(
+            !command.status().map(|s| !s.success()).unwrap_or(true),
+            "Couldn't create runtime archive!"
+        );
+
+        #[cfg(feature = "embed-runtime")]
+        {
+            // NOTE: lib, .a are added always on unix-like systems as described in:
+            // https://gist.github.com/novafacing/1389cbb2f0a362d7eb103e67b4468e2b
+            println!(
+                "cargo:rustc-env=LIBAFL_LIBFUZZER_RUNTIME_PATH={}",
+                custom_lib_dir.join("libFuzzer.a").display()
+            );
+        }
+
         println!(
-            "cargo:rustc-env=LIBAFL_LIBFUZZER_RUNTIME_PATH={}",
-            lib_path.join("libafl_libfuzzer_runtime.a").display()
+            "cargo:rustc-link-search=native={}",
+            custom_lib_dir.to_str().unwrap()
         );
+        println!("cargo:rustc-link-lib=static=Fuzzer");
+    } else {
+        println!(
+            "cargo:rustc-link-search=native={}",
+            lib_path.to_str().unwrap()
+        );
+        println!("cargo:rustc-link-lib=static=afl_fuzzer_runtime");
     }
 
-    println!(
-        "cargo:rustc-link-search=native={}",
-        lib_path.to_str().unwrap()
-    );
-    println!("cargo:rustc-link-lib=static=afl_libfuzzer_runtime");
     println!("cargo:rustc-link-lib=stdc++");
 }

libafl_libfuzzer/libafl_libfuzzer_runtime/Cargo.toml

@@ -37,7 +37,7 @@ libafl_targets = { path = "../../libafl_targets", features = ["sancov_8bit", "sa
 ahash = { version = "0.8.3", default-features = false }
 libc = "0.2.139"
 log = "0.4.17"
-mimalloc = { version = "0.1.34", default-features = false, optional = true }
+mimalloc = { version = "0.1.34", default-features = false }
 num-traits = "0.2.15"
 rand = "0.8.5"
 serde = { version = "1.0", default-features = false, features = ["alloc", "derive"] } # serialization lib

libafl_libfuzzer/libafl_libfuzzer_runtime/src/lib.rs

@@ -79,8 +79,11 @@ use libafl::{
     Error,
 };
 use libafl_bolts::AsSlice;
+use mimalloc::MiMalloc;
 
 use crate::options::{LibfuzzerMode, LibfuzzerOptions};
+#[global_allocator]
+static GLOBAL: MiMalloc = MiMalloc;
 
 mod feedbacks;
 mod fuzz;