Use Unix timer_* API instead of setitimer (#510)

* fix linter errors for armv7 (docs)

* introduce HasOnCrashReset trait; use timer_* API instead of setitimer for unix TimeoutExecutor

* fixes: PR #469 annotations and CI issues

* reintroduce setitimer for apple as macOS does not feature the POSIX timer API

* more macos and windows CI fixes

* more macos and windows CI fixes cont.

* HasOnCrashReset -> HasPostRunReset

* remove drop impl for Windows TimeoutExecutor

* adjust target cfgs for timeout stuff (android also did not work)

* add call to inner post_run_reset

* remove HasPostRunReset in favor of making it a trait fn of Executor

* add post_run_reset's to CombinedExecutor

* clippy: addr_of! instead of raw pointer casts

* link librt in libafl_cc (required by timer_* API)

* minor fixes and cleanup

* remove unused import for targets other than linux

* fix win

* merge

* fix

Co-authored-by: pr0me <g33sus@gmail.com>

libafl/src/bolts/os/unix_signals.rs

@@ -17,42 +17,72 @@ use std::ffi::CString;
 #[cfg(target_arch = "arm")]
 pub use libc::c_ulong;
 
+/// ARMv7-specific representation of a saved context
 #[cfg(target_arch = "arm")]
+#[derive(Debug)]
 #[allow(non_camel_case_types)]
 #[repr(C)]
 pub struct mcontext_t {
+    /// Signal Number
     pub trap_no: c_ulong,
+    /// Error Code
     pub error_code: c_ulong,
+    /// Old signal mask
     pub oldmask: c_ulong,
+    /// GPR R0
     pub arm_r0: c_ulong,
+    /// GPR R1
     pub arm_r1: c_ulong,
+    /// GPR R2
     pub arm_r2: c_ulong,
+    /// GPR R3
     pub arm_r3: c_ulong,
+    /// GPR R4
     pub arm_r4: c_ulong,
+    /// GPR R5
     pub arm_r5: c_ulong,
+    /// GPR R6
     pub arm_r6: c_ulong,
+    /// GPR R7
     pub arm_r7: c_ulong,
+    /// GPR R8
     pub arm_r8: c_ulong,
+    /// GPR R9
     pub arm_r9: c_ulong,
+    /// GPR R10
     pub arm_r10: c_ulong,
+    /// Frame Pointer
     pub arm_fp: c_ulong,
+    /// Intra-Procedure Scratch Register
     pub arm_ip: c_ulong,
+    /// Stack Pointer
     pub arm_sp: c_ulong,
+    /// Link Register
     pub arm_lr: c_ulong,
+    /// Program Counter
     pub arm_pc: c_ulong,
+    /// Current Program Status Register
     pub arm_cpsr: c_ulong,
+    /// Fault Address
     pub fault_address: c_ulong,
 }
 
+/// User Context Struct
 #[cfg(target_arch = "arm")]
+#[derive(Debug)]
 #[allow(non_camel_case_types)]
 #[repr(C)]
 pub struct ucontext_t {
+    /// Flags
     pub uc_flags: u32,
+    /// Pointer to the context that will be resumed when this context returns
     pub uc_link: *mut ucontext_t,
+    /// Stack used by this context
     pub uc_stack: stack_t,
+    /// Machine-specific representation of the saved context
     pub uc_mcontext: mcontext_t,
-    pub uc_sigmask: nix::sys::signal::SigSet,
+    /// Set of signals that are blocked when this context is active
+    pub uc_sigmask: libc::sigset_t,
 }
 
 #[cfg(not(target_arch = "arm"))]

libafl/src/bolts/shmem.rs

@@ -1118,7 +1118,6 @@ pub mod win32_shmem {
         fmt::{self, Debug, Formatter},
         ptr, slice,
     };
-    use std::convert::TryInto;
     use uuid::Uuid;
 
     const INVALID_HANDLE_VALUE: isize = -1;

libafl/src/executors/combined.rs

@@ -50,7 +50,10 @@ where
         mgr: &mut EM,
         input: &I,
     ) -> Result<ExitKind, Error> {
-        self.primary.run_target(fuzzer, state, mgr, input)
+        let ret = self.primary.run_target(fuzzer, state, mgr, input);
+        self.primary.post_run_reset();
+        self.secondary.post_run_reset();
+        ret
     }
 }
 

libafl/src/executors/inprocess.rs

@@ -305,7 +305,7 @@ impl InProcessHandlers {
     pub fn new<E, EM, I, OF, OT, S, Z, H>() -> Result<Self, Error>
     where
         I: Input,
-        E: HasObservers<I, OT, S>,
+        E: Executor<EM, I, S, Z> + HasObservers<I, OT, S>,
         OT: ObserversTuple<I, S>,
         EM: EventFirer<I> + EventRestarter<S>,
         OF: Feedback<I, S>,
@@ -628,8 +628,7 @@ mod unix_signal_handler {
         events::{Event, EventFirer, EventRestarter},
         executors::{
             inprocess::{InProcessExecutorHandlerData, GLOBAL_STATE},
-            timeout::unix_remove_timeout,
-            ExitKind, HasObservers,
+            Executor, ExitKind, HasObservers,
         },
         feedbacks::Feedback,
         fuzzer::HasObjective,
@@ -775,7 +774,7 @@ mod unix_signal_handler {
         _context: &mut ucontext_t,
         data: &mut InProcessExecutorHandlerData,
     ) where
-        E: HasObservers<I, OT, S>,
+        E: Executor<EM, I, S, Z> + HasObservers<I, OT, S>,
         EM: EventFirer<I> + EventRestarter<S>,
         OT: ObserversTuple<I, S>,
         OF: Feedback<I, S>,
@@ -783,8 +782,6 @@ mod unix_signal_handler {
         I: Input,
         Z: HasObjective<I, OF, S>,
     {
-        unix_remove_timeout();
-
         #[cfg(all(target_os = "android", target_arch = "aarch64"))]
         let _context = &mut *(((_context as *mut _ as *mut libc::c_void as usize) + 128)
             as *mut libc::c_void as *mut ucontext_t);
@@ -825,11 +822,14 @@ mod unix_signal_handler {
 
             // TODO tell the parent to not restart
         } else {
+            let executor = (data.executor_ptr as *mut E).as_mut().unwrap();
+            // disarms timeout in case of TimeoutExecutor
+            executor.post_run_reset();
             let state = (data.state_ptr as *mut S).as_mut().unwrap();
             let event_mgr = (data.event_mgr_ptr as *mut EM).as_mut().unwrap();
             let fuzzer = (data.fuzzer_ptr as *mut Z).as_mut().unwrap();
-            let executor = (data.executor_ptr as *mut E).as_mut().unwrap();
             let observers = executor.observers_mut();
+
             let input = (data.current_input_ptr as *const I).as_ref().unwrap();
             data.current_input_ptr = ptr::null();
 
@@ -908,8 +908,7 @@ mod windows_exception_handler {
         events::{Event, EventFirer, EventRestarter},
         executors::{
             inprocess::{InProcessExecutorHandlerData, GLOBAL_STATE},
-            timeout::windows_delete_timer_queue,
-            ExitKind, HasObservers,
+            Executor, ExitKind, HasObservers,
         },
         feedbacks::Feedback,
         fuzzer::HasObjective,
@@ -1053,7 +1052,7 @@ mod windows_exception_handler {
         exception_pointers: *mut EXCEPTION_POINTERS,
         data: &mut InProcessExecutorHandlerData,
     ) where
-        E: HasObservers<I, OT, S>,
+        E: Executor<EM, I, S, Z> + HasObservers<I, OT, S>,
         EM: EventFirer<I> + EventRestarter<S>,
         OT: ObserversTuple<I, S>,
         OF: Feedback<I, S>,
@@ -1062,7 +1061,7 @@ mod windows_exception_handler {
         Z: HasObjective<I, OF, S>,
     {
         // Have we set a timer_before?
-        if let Some(x) =
+        if let Some(_) =
             (data.tp_timer as *mut windows::Win32::System::Threading::TP_TIMER).as_mut()
         {
             /*
@@ -1077,9 +1076,6 @@ mod windows_exception_handler {
             compiler_fence(Ordering::SeqCst);
             LeaveCriticalSection(data.critical as *mut RTL_CRITICAL_SECTION);
             compiler_fence(Ordering::SeqCst);
-
-            windows_delete_timer_queue(x);
-            data.tp_timer = ptr::null_mut();
         }
 
         let code = ExceptionCode::try_from(
@@ -1124,10 +1120,16 @@ mod windows_exception_handler {
 
             // TODO tell the parent to not restart
         } else {
+            let executor = (data.executor_ptr as *mut E).as_mut().unwrap();
+            // reset timer
+            if !data.tp_timer.is_null() {
+                executor.post_run_reset();
+                data.tp_timer = ptr::null_mut();
+            }
+
             let state = (data.state_ptr as *mut S).as_mut().unwrap();
             let event_mgr = (data.event_mgr_ptr as *mut EM).as_mut().unwrap();
             let fuzzer = (data.fuzzer_ptr as *mut Z).as_mut().unwrap();
-            let executor = (data.executor_ptr as *const E).as_ref().unwrap();
             let observers = executor.observers();
 
             #[cfg(feature = "std")]

libafl/src/executors/mod.rs

@@ -95,6 +95,10 @@ where
     {
         WithObservers::new(self, observers)
     }
+
+    /// Custom Reset Handler, e.g., to reset timers
+    #[inline]
+    fn post_run_reset(&mut self) {}
 }
 
 /// A simple executor that does nothing.

libafl/src/executors/timeout.rs

@@ -18,16 +18,20 @@ use crate::executors::inprocess::{HasInProcessHandlers, GLOBAL_STATE};
 
 #[cfg(unix)]
 use core::{mem::zeroed, ptr::null_mut};
-#[cfg(unix)]
+
+#[cfg(target_os = "linux")]
+use core::ptr::{addr_of, addr_of_mut};
+
+#[cfg(all(unix, not(target_os = "linux")))]
 use libc::c_int;
 
 #[cfg(all(windows, feature = "std"))]
 use windows::Win32::{
     Foundation::FILETIME,
     System::Threading::{
-        CloseThreadpoolTimer, CreateThreadpoolTimer, EnterCriticalSection,
-        InitializeCriticalSection, LeaveCriticalSection, SetThreadpoolTimer, RTL_CRITICAL_SECTION,
-        TP_CALLBACK_ENVIRON_V3, TP_CALLBACK_INSTANCE, TP_TIMER,
+        CreateThreadpoolTimer, EnterCriticalSection, InitializeCriticalSection,
+        LeaveCriticalSection, SetThreadpoolTimer, RTL_CRITICAL_SECTION, TP_CALLBACK_ENVIRON_V3,
+        TP_CALLBACK_INSTANCE, TP_TIMER,
     },
 };
 
@@ -38,13 +42,13 @@ use core::{ffi::c_void, ptr::write_volatile};
 use core::sync::atomic::{compiler_fence, Ordering};
 
 #[repr(C)]
-#[cfg(unix)]
+#[cfg(all(unix, not(target_os = "linux")))]
 struct Timeval {
     pub tv_sec: i64,
     pub tv_usec: i64,
 }
 
-#[cfg(unix)]
+#[cfg(all(unix, not(target_os = "linux")))]
 impl Debug for Timeval {
     #[allow(clippy::cast_sign_loss)]
     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
@@ -59,42 +63,29 @@ impl Debug for Timeval {
 }
 
 #[repr(C)]
-#[cfg(unix)]
+#[cfg(all(unix, not(target_os = "linux")))]
 #[derive(Debug)]
 struct Itimerval {
     pub it_interval: Timeval,
     pub it_value: Timeval,
 }
 
-#[cfg(unix)]
+#[cfg(all(unix, not(target_os = "linux")))]
 extern "C" {
     fn setitimer(which: c_int, new_value: *mut Itimerval, old_value: *mut Itimerval) -> c_int;
 }
 
-#[cfg(unix)]
+#[cfg(all(unix, not(target_os = "linux")))]
 const ITIMER_REAL: c_int = 0;
 
-/// Reset and remove the timeout
-#[cfg(unix)]
-pub(crate) fn unix_remove_timeout() {
-    unsafe {
-        let mut itimerval_zero: Itimerval = zeroed();
-        setitimer(ITIMER_REAL, &mut itimerval_zero, null_mut());
-    }
-}
-
-/// Deletes this timer queue
-/// # Safety
-/// Will dereference the given `tp_timer` pointer, unchecked.
-#[cfg(all(windows, feature = "std"))]
-pub(crate) unsafe fn windows_delete_timer_queue(tp_timer: *mut TP_TIMER) {
-    CloseThreadpoolTimer(tp_timer);
-}
-
 /// The timeout excutor is a wrapper that sets a timeout before each run
 pub struct TimeoutExecutor<E> {
     executor: E,
-    #[cfg(unix)]
+    #[cfg(target_os = "linux")]
+    itimerspec: libc::itimerspec,
+    #[cfg(target_os = "linux")]
+    timerid: libc::timer_t,
+    #[cfg(all(unix, not(target_os = "linux")))]
     itimerval: Itimerval,
     #[cfg(windows)]
     milli_sec: i64,
@@ -113,7 +104,19 @@ impl<E: Debug> Debug for TimeoutExecutor<E> {
             .finish_non_exhaustive()
     }
 
-    #[cfg(unix)]
+    #[cfg(target_os = "linux")]
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        f.debug_struct("TimeoutExecutor")
+            .field("executor", &self.executor)
+            .field(
+                "milli_sec",
+                &(&self.itimerspec.it_value.tv_sec * 1000
+                    + &self.itimerspec.it_value.tv_nsec / 1000 / 1000),
+            )
+            .finish()
+    }
+
+    #[cfg(all(unix, not(target_os = "linux")))]
     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
         f.debug_struct("TimeoutExecutor")
             .field("executor", &self.executor)
@@ -130,7 +133,56 @@ type PTP_TIMER_CALLBACK = unsafe extern "system" fn(
     param2: *mut TP_TIMER,
 );
 
-#[cfg(unix)]
+#[cfg(target_os = "linux")]
+impl<E> TimeoutExecutor<E> {
+    /// Create a new [`TimeoutExecutor`], wrapping the given `executor` and checking for timeouts.
+    /// This should usually be used for `InProcess` fuzzing.
+    pub fn new(executor: E, exec_tmout: Duration) -> Self {
+        let milli_sec = exec_tmout.as_millis();
+        let it_value = libc::timespec {
+            tv_sec: (milli_sec / 1000) as _,
+            tv_nsec: ((milli_sec % 1000) * 1000 * 1000) as _,
+        };
+        let it_interval = libc::timespec {
+            tv_sec: 0,
+            tv_nsec: 0,
+        };
+        let itimerspec = libc::itimerspec {
+            it_interval,
+            it_value,
+        };
+        let mut timerid: libc::timer_t = null_mut();
+        unsafe {
+            // creates a new per-process interval timer
+            libc::timer_create(libc::CLOCK_MONOTONIC, null_mut(), addr_of_mut!(timerid));
+        }
+        Self {
+            executor,
+            itimerspec,
+            timerid,
+        }
+    }
+
+    /// Set the timeout for this executor
+    pub fn set_timeout(&mut self, exec_tmout: Duration) {
+        let milli_sec = exec_tmout.as_millis();
+        let it_value = libc::timespec {
+            tv_sec: (milli_sec / 1000) as _,
+            tv_nsec: ((milli_sec % 1000) * 1000 * 1000) as _,
+        };
+        let it_interval = libc::timespec {
+            tv_sec: 0,
+            tv_nsec: 0,
+        };
+        let itimerspec = libc::itimerspec {
+            it_interval,
+            it_value,
+        };
+        self.itimerspec = itimerspec;
+    }
+}
+
+#[cfg(all(unix, not(target_os = "linux")))]
 impl<E> TimeoutExecutor<E> {
     /// Create a new [`TimeoutExecutor`], wrapping the given `executor` and checking for timeouts.
     /// This should usually be used for `InProcess` fuzzing.
@@ -153,6 +205,24 @@ impl<E> TimeoutExecutor<E> {
             itimerval,
         }
     }
+
+    /// Set the timeout for this executor
+    pub fn set_timeout(&mut self, exec_tmout: Duration) {
+        let milli_sec = exec_tmout.as_millis();
+        let it_value = Timeval {
+            tv_sec: (milli_sec / 1000) as i64,
+            tv_usec: (milli_sec % 1000) as i64,
+        };
+        let it_interval = Timeval {
+            tv_sec: 0,
+            tv_usec: 0,
+        };
+        let itimerval = Itimerval {
+            it_interval,
+            it_value,
+        };
+        self.itimerval = itimerval;
+    }
 }
 
 #[cfg(windows)]
@@ -183,25 +253,6 @@ impl<E: HasInProcessHandlers> TimeoutExecutor<E> {
         }
     }
 
-    /// Set the timeout for this executor
-    #[cfg(unix)]
-    pub fn set_timeout(&mut self, exec_tmout: Duration) {
-        let milli_sec = exec_tmout.as_millis();
-        let it_value = Timeval {
-            tv_sec: (milli_sec / 1000) as i64,
-            tv_usec: (milli_sec % 1000) as i64,
-        };
-        let it_interval = Timeval {
-            tv_sec: 0,
-            tv_usec: 0,
-        };
-        let itimerval = Itimerval {
-            it_interval,
-            it_value,
-        };
-        self.itimerval = itimerval;
-    }
-
     /// Set the timeout for this executor
     #[cfg(windows)]
     pub fn set_timeout(&mut self, exec_tmout: Duration) {
@@ -212,15 +263,6 @@ impl<E: HasInProcessHandlers> TimeoutExecutor<E> {
     pub fn inner(&mut self) -> &mut E {
         &mut self.executor
     }
-
-    /// Reset the timeout for this executor
-    #[cfg(windows)]
-    pub fn windows_reset_timeout(&self) -> Result<(), Error> {
-        unsafe {
-            SetThreadpoolTimer(self.tp_timer, core::ptr::null(), 0, 0);
-        }
-        Ok(())
-    }
 }
 
 #[cfg(windows)]
@@ -277,13 +319,54 @@ where
 
             write_volatile(&mut data.timeout_input_ptr, core::ptr::null_mut());
 
-            self.windows_reset_timeout()?;
+            self.post_run_reset();
             ret
         }
     }
+
+    /// Deletes this timer queue
+    /// # Safety
+    /// Will dereference the given `tp_timer` pointer, unchecked.
+    fn post_run_reset(&mut self) {
+        unsafe {
+            SetThreadpoolTimer(self.tp_timer, core::ptr::null(), 0, 0);
+        }
+        self.executor.post_run_reset();
+    }
 }
 
-#[cfg(unix)]
+#[cfg(target_os = "linux")]
+impl<E, EM, I, S, Z> Executor<EM, I, S, Z> for TimeoutExecutor<E>
+where
+    E: Executor<EM, I, S, Z>,
+    I: Input,
+{
+    fn run_target(
+        &mut self,
+        fuzzer: &mut Z,
+        state: &mut S,
+        mgr: &mut EM,
+        input: &I,
+    ) -> Result<ExitKind, Error> {
+        unsafe {
+            libc::timer_settime(self.timerid, 0, addr_of_mut!(self.itimerspec), null_mut());
+            let ret = self.executor.run_target(fuzzer, state, mgr, input);
+            // reset timer
+            self.post_run_reset();
+            ret
+        }
+    }
+
+    fn post_run_reset(&mut self) {
+        unsafe {
+            let disarmed: libc::itimerspec = zeroed();
+            libc::timer_settime(self.timerid, 0, addr_of!(disarmed), null_mut());
+        }
+        self.executor.post_run_reset();
+    }
+}
+
+#[cfg(all(unix, not(target_os = "linux")))]
 impl<E, EM, I, S, Z> Executor<EM, I, S, Z> for TimeoutExecutor<E>
 where
     E: Executor<EM, I, S, Z>,
@@ -296,14 +379,21 @@ where
         mgr: &mut EM,
         input: &I,
     ) -> Result<ExitKind, Error> {
-        #[cfg(unix)]
         unsafe {
             setitimer(ITIMER_REAL, &mut self.itimerval, null_mut());
             let ret = self.executor.run_target(fuzzer, state, mgr, input);
-            unix_remove_timeout();
+            self.post_run_reset();
             ret
         }
     }
+
+    fn post_run_reset(&mut self) {
+        unsafe {
+            let mut itimerval_zero: Itimerval = zeroed();
+            setitimer(ITIMER_REAL, &mut itimerval_zero, null_mut());
+        }
+        self.executor.post_run_reset();
+    }
 }
 
 impl<E, I, OT, S> HasObservers<I, OT, S> for TimeoutExecutor<E>
@@ -321,12 +411,3 @@ where
         self.executor.observers_mut()
     }
 }
-
-#[cfg(windows)]
-impl<E> Drop for TimeoutExecutor<E> {
-    fn drop(&mut self) {
-        unsafe {
-            windows_delete_timer_queue(self.tp_timer);
-        }
-    }
-}

libafl_cc/src/clang.rs

@@ -154,6 +154,11 @@ impl CompilerWrapper for ClangWrapper {
             new_args.push("-lBcrypt".into());
             new_args.push("-lAdvapi32".into());
         }
+        // required by timer API (timer_create, timer_settime)
+        #[cfg(target_os = "linux")]
+        if linking {
+            new_args.push("-lrt".into());
+        }
         // MacOS has odd linker behavior sometimes
         #[cfg(target_vendor = "apple")]
         if linking {