Various improvements

Replace TimeObserver with ClockObserver
Add a Maximization Scheduler for Clocks
Factor out icount Metadata from Feedback
Allow Breakpoint removal in systemmode

fuzzers/wcet_qemu_sys/src/fuzzer.rs

@@ -1,6 +1,9 @@
 //! A singlethreaded QEMU fuzzer that can auto-restart.
 
-use libafl_qemu::QemuClockObserver;
+use libafl::mutators::ByteFlipMutator;
+use libafl::mutators::BitFlipMutator;
+use crate::worst::LenTimeMaximizerCorpusScheduler;
+use libafl::corpus::MinimizerCorpusScheduler;
 use hashbrown::HashMap;
 use libafl::events::SimpleEventManager;
 use clap::{App, Arg};
@@ -57,6 +60,10 @@ use libafl_qemu::{
     filter_qemu_args,
     snapshot_sys::QemuSysSnapshotHelper,
     QemuExecutor,
+    clock,
+    QemuClockObserver,
+    clock::ClockFeedback,
+    clock::QemuClockIncreaseFeedback
 };
 use crate::worst::{HitFeedback,HitcountsMapObserver,HitImprovingFeedback};
 
@@ -283,7 +290,7 @@ fn fuzz(
         HitcountsMapObserver::new(VariableMapObserver::new("edges", edges, edges_counter));
 
     // Create an observation channel to keep track of the execution time
-    let time_observer = TimeObserver::new("time");
+    // let time_observer = TimeObserver::new("time");
     let clock_observer = QemuClockObserver::default();
 
     // Create an observation channel using cmplog map
@@ -304,7 +311,9 @@ fn fuzz(
     };
     let feedback = feedback_or!(
         MaxMapFeedback::new_tracking(&feedback_state, &edges_observer, true, false),
-        HitImprovingFeedback::new(target_map.clone())
+        HitImprovingFeedback::new(target_map.clone()),
+        QemuClockIncreaseFeedback::default(),
+        ClockFeedback::new_with_observer(&clock_observer)
     );
     // let feedback = feedback_or!(
     //     // New maximization map feedback linked to the edges observer and the feedback state
@@ -329,7 +338,7 @@ fn fuzz(
             OnDiskCorpus::new(objective_dir).unwrap(),
             // States of the feedbacks.
             // They are the data related to the feedbacks that you want to persist in the State.
-            tuple_list!(feedback_state),
+            tuple_list!(feedback_state,clock::MaxIcountMetadata::default()),
         )
     };
 
@@ -380,7 +389,7 @@ fn fuzz(
             //QemuAsanHelper::new(),
             QemuSysSnapshotHelper::new()
         ),
-        tuple_list!(edges_observer, time_observer, clock_observer),
+        tuple_list!(edges_observer, clock_observer),
         &mut fuzzer,
         &mut state,
         &mut mgr,

fuzzers/wcet_qemu_sys/src/worst.rs

@@ -1,3 +1,8 @@
+use libafl::feedbacks::MapIndexesMetadata;
+use libafl::corpus::Testcase;
+use libafl::corpus::FavFactor;
+use core::marker::PhantomData;
+use libafl::corpus::MinimizerCorpusScheduler;
 use std::path::PathBuf;
 use std::fs;
 use libafl::observers::VariableMapObserver;
@@ -185,7 +190,7 @@ where
         }
         let mean_sum_of_squares = (sum_of_square_difference as f64) / (self.target_map.len() as f64);
         let hit_target = mean_sum_of_squares <= self.target_msd;
-        eprintln!("hit target: {} {} {:?}",hit_target,mean_sum_of_squares, _input);
+        // eprintln!("hit target: {} {} {:?}",hit_target,mean_sum_of_squares, _input);
         if hit_target {
             Ok(true)
         } else {
@@ -314,9 +319,10 @@ where
             }
         }
         let mean_sum_of_squares = (sum_of_square_difference as f64) / (self.target_map.len() as f64);
-        let hit_target = mean_sum_of_squares <= self.best_msd;
-        eprintln!("improving: {}",hit_target);
+        let hit_target = mean_sum_of_squares < self.best_msd;
+        // eprintln!("improving: {}",hit_target);
         if hit_target {
+            // println!("Hit Improving: {}",mean_sum_of_squares);
             self.best_msd = mean_sum_of_squares;
             Ok(true)
         } else {
@@ -408,7 +414,7 @@ impl Default for DumpMapFeedback {
 }
 
 //=========================== Debugging Feedback
-/// A [`Feedback`] meant to dump the edgemap for debugging.
+/// A NoOp [`Feedback`] with fixed response.
 #[derive(Debug)]
 pub struct DummyFeedback {
     response: bool
@@ -456,3 +462,27 @@ impl Default for DummyFeedback {
         Self::new(true)
     }
 }
+
+pub type LenTimeMaximizerCorpusScheduler<CS, I, S> =
+    MinimizerCorpusScheduler<CS, MaxLenTimeFavFactor<I>, I, MapIndexesMetadata, S>;
+
+/// Multiply the testcase size with the execution time.
+/// This favors small and quick testcases.
+#[derive(Debug, Clone)]
+pub struct MaxLenTimeFavFactor<I>
+where
+    I: Input + HasLen,
+{
+    phantom: PhantomData<I>,
+}
+
+impl<I> FavFactor<I> for MaxLenTimeFavFactor<I>
+where
+    I: Input + HasLen,
+{
+    fn compute(entry: &mut Testcase<I>) -> Result<u64, Error> {
+        // TODO maybe enforce entry.exec_time().is_some()
+        let execs_per_hour = (3600.0/entry.exec_time().expect("testcase.exec_time is needed for scheduler").as_secs_f64()) as u64;
+        Ok(execs_per_hour)
+    }
+}

libafl_qemu/src/clock.rs

@@ -31,21 +31,66 @@ use libafl::feedbacks::Feedback;
 use libafl::SerdeAny;
 use libafl::state::HasMetadata;
 use libafl::corpus::testcase::Testcase;
+use core::{fmt::Debug, time::Duration};
+use libafl::feedbacks::FeedbackState;
+use libafl::state::HasFeedbackStates;
+use libafl::bolts::tuples::MatchName;
 
 //========== Metadata
 #[derive(Debug, Serialize, Deserialize, SerdeAny)]
 pub struct QemuIcountMetadata {
-    runtime: i64,
+    runtime: u64,
 }
 // libafl::impl_serdeany!(QemuIcountMetadata);
 
+/// Metadata for [`QemuClockIncreaseFeedback`]
+#[derive(Debug, Serialize, Deserialize, SerdeAny)]
+pub struct MaxIcountMetadata {
+    pub max_icount_seen: u64,
+    pub name: String,
+}
+
+impl FeedbackState for MaxIcountMetadata
+{
+    fn reset(&mut self) -> Result<(), Error> {
+        self.max_icount_seen = 0;
+        Ok(())
+    }
+}
+
+impl Named for MaxIcountMetadata
+{
+    #[inline]
+    fn name(&self) -> &str {
+        self.name.as_str()
+    }
+}
+
+impl MaxIcountMetadata
+{
+    /// Create new `MaxIcountMetadata`
+    #[must_use]
+    pub fn new(name: &'static str) -> Self {
+        Self {
+            max_icount_seen: 0,
+            name: name.to_string(),
+        }
+    }
+}
+
+impl Default for MaxIcountMetadata {
+    fn default() -> Self {
+        Self::new("MaxClock")
+    }
+}
+
 //========== Observer
 
 /// A simple observer, just overlooking the runtime of the target.
 #[derive(Serialize, Deserialize, Debug, Clone)]
 pub struct QemuClockObserver {
     name: String,
-    last_runtime: i64,
+    last_runtime: u64,
 }
 
 impl QemuClockObserver {
@@ -60,7 +105,7 @@ impl QemuClockObserver {
 
     /// Gets the runtime for the last execution of this target.
     #[must_use]
-    pub fn last_runtime(&self) -> i64 {
+    pub fn last_runtime(&self) -> u64 {
         self.last_runtime
     }
 }
@@ -83,7 +128,7 @@ where
         // } else {
         //     println!("Found Metadata");
         // }
-        println!("Observer Clock: {}",self.last_runtime());
+        // println!("Observer Clock: {}",self.last_runtime());
         Ok(())
     }
 }
@@ -105,15 +150,16 @@ impl Default for QemuClockObserver {
 }
 
 //========== Feedback
-
-/// A [`Feedback`] rewarding increasing the execution cycles on Qemu.
-#[derive(Debug)]
-pub struct QemuClockIncreaseFeedback {
-    maximum: i64,
-    last_runtime: i64,
+/// Nop feedback that annotates execution time in the new testcase, if any
+/// for this Feedback, the testcase is never interesting (use with an OR)
+/// It decides, if the given [`ClockObserver`] value of a run is interesting.
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct ClockFeedback {
+    exec_time: Option<u64>,
+    name: String,
 }
 
-impl<I, S> Feedback<I, S> for QemuClockIncreaseFeedback
+impl<I, S> Feedback<I, S> for ClockFeedback
 where
     I: Input,
     S: HasClientPerfMonitor,
@@ -123,6 +169,81 @@ where
         _state: &mut S,
         _manager: &mut EM,
         _input: &I,
+        observers: &OT,
+        _exit_kind: &ExitKind,
+    ) -> Result<bool, Error>
+    where
+        EM: EventFirer<I>,
+        OT: ObserversTuple<I, S>,
+    {
+        // TODO Replace with match_name_type when stable
+        let observer = observers.match_name::<QemuClockObserver>(self.name()).unwrap();
+        self.exec_time = Some(observer.last_runtime());
+        Ok(false)
+    }
+
+    /// Append to the testcase the generated metadata in case of a new corpus item
+    #[inline]
+    fn append_metadata(&mut self, _state: &mut S, testcase: &mut Testcase<I>) -> Result<(), Error> {
+        *testcase.exec_time_mut() = match self.exec_time {
+            Some(s) => Some(Duration::new(0,360*s as u32)),
+            None => None,
+        };
+        self.exec_time = None;
+        Ok(())
+    }
+
+    /// Discard the stored metadata in case that the testcase is not added to the corpus
+    #[inline]
+    fn discard_metadata(&mut self, _state: &mut S, _input: &I) -> Result<(), Error> {
+        self.exec_time = None;
+        Ok(())
+    }
+}
+
+impl Named for ClockFeedback {
+    #[inline]
+    fn name(&self) -> &str {
+        self.name.as_str()
+    }
+}
+
+impl ClockFeedback {
+    /// Creates a new [`ClockFeedback`], deciding if the value of a [`TimeObserver`] with the given `name` of a run is interesting.
+    #[must_use]
+    pub fn new(name: &'static str) -> Self {
+        Self {
+            exec_time: None,
+            name: name.to_string(),
+        }
+    }
+
+    /// Creates a new [`ClockFeedback`], deciding if the given [`TimeObserver`] value of a run is interesting.
+    #[must_use]
+    pub fn new_with_observer(observer: &QemuClockObserver) -> Self {
+        Self {
+            exec_time: None,
+            name: observer.name().to_string(),
+        }
+    }
+}
+
+/// A [`Feedback`] rewarding increasing the execution cycles on Qemu.
+#[derive(Debug)]
+pub struct QemuClockIncreaseFeedback {
+    name: String,
+}
+
+impl<I, S> Feedback<I, S> for QemuClockIncreaseFeedback
+where
+    I: Input,
+    S: HasFeedbackStates + HasClientPerfMonitor,
+{
+    fn is_interesting<EM, OT>(
+        &mut self,
+        state: &mut S,
+        _manager: &mut EM,
+        _input: &I,
         _observers: &OT,
         _exit_kind: &ExitKind,
     ) -> Result<bool, Error>
@@ -132,8 +253,13 @@ where
     {
         let observer = _observers.match_name::<QemuClockObserver>("clock")
             .expect("QemuClockObserver not found");
-        if observer.last_runtime() > self.maximum {
-            self.maximum = observer.last_runtime();
+        let clock_state = state
+            .feedback_states_mut()
+            .match_name_mut::<MaxIcountMetadata>(&self.name)
+            .unwrap();
+        if observer.last_runtime() > clock_state.max_icount_seen {
+            // println!("Clock improving {}",observer.last_runtime());
+            clock_state.max_icount_seen = observer.last_runtime();
             return Ok(true);
         }
         Ok(false)
@@ -142,7 +268,7 @@ where
     /// Append to the testcase the generated metadata in case of a new corpus item
     #[inline]
     fn append_metadata(&mut self, _state: &mut S, testcase: &mut Testcase<I>) -> Result<(), Error> {
-        testcase.metadata_mut().insert(QemuIcountMetadata{runtime: self.last_runtime});
+        // testcase.metadata_mut().insert(QemuIcountMetadata{runtime: self.last_runtime});
         Ok(())
     }
 
@@ -157,20 +283,20 @@ where
 impl Named for QemuClockIncreaseFeedback {
     #[inline]
     fn name(&self) -> &str {
-        "QemuClockFeedback"
+        &self.name
     }
 }
 
 impl QemuClockIncreaseFeedback {
     /// Creates a new [`HitFeedback`]
     #[must_use]
-    pub fn new() -> Self {
-        Self {maximum: 0, last_runtime: 0}
+    pub fn new(name: &'static str) -> Self {
+        Self {name: String::from(name)}
     }
 }
 
 impl Default for QemuClockIncreaseFeedback {
     fn default() -> Self {
-        Self::new()
+        Self::new("MaxClock")
     }
 }

libafl_qemu/src/emu.rs

@@ -183,6 +183,8 @@ extern "C" {
     fn libafl_qemu_set_breakpoint(addr: u64) -> i32;
     #[cfg(feature = "systemmode")]
     fn libafl_qemu_set_native_breakpoint(addr: u64) -> i32;
+    #[cfg(feature = "systemmode")]
+    fn libafl_qemu_remove_native_breakpoint(addr: u64) -> i32;
     fn libafl_qemu_remove_breakpoint(addr: u64) -> i32;
     fn libafl_qemu_set_hook(addr: u64, callback: extern "C" fn(u64), val: u64) -> i32;
     fn libafl_qemu_remove_hook(addr: u64) -> i32;
@@ -200,7 +202,7 @@ extern "C" {
     #[cfg(feature = "systemmode")]
     fn libafl_snapshot_load(name: *const c_char) -> i32;
     #[cfg(feature = "systemmode")]
-    pub fn libafl_get_clock() -> i64;
+    pub fn libafl_get_clock() -> u64;
 
     fn strlen(s: *const u8) -> usize;
 
@@ -438,6 +440,9 @@ impl Emulator {
 
     pub fn remove_breakpoint(&self, addr: u64) {
         unsafe {
+            #[cfg(feature = "systemmode")]
+            libafl_qemu_remove_native_breakpoint(addr);
+            #[cfg(not(feature = "systemmode"))]
             libafl_qemu_remove_breakpoint(addr);
         }
     }
@@ -682,7 +687,7 @@ impl Emulator {
     }
 
     #[cfg(feature = "systemmode")]
-    pub fn get_ticks(&self) -> i64{
+    pub fn get_ticks(&self) -> u64{
         return unsafe { libafl_get_clock() };
     }
 }