Added: Remaining W^X fixes for M1 macOS

src-rust/src/internal/buffer_allocator_osx.rs

@@ -132,13 +132,25 @@ fn try_allocate_buffer(
             continue;
         }
 
+        // TODO: M1 W^X
+        // M1 macOS has strict W^X enforcement where pages are not allowed to be writeable
+        // and executable at the same time. Therefore, we have to work around this by allocating as RW
+        // and temporarily changing it on every write.
+
+        // This is not safe, but later we'll get a better workaround going.
+        #[cfg(not(all(target_os = "macos", target_arch = "aarch64")))]
+        const PROT: vm_prot_t = VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE;
+
+        #[cfg(all(target_os = "macos", target_arch = "aarch64"))]
+        const PROT: vm_prot_t = VM_PROT_READ | VM_PROT_WRITE;
+
         kr = unsafe {
             mach_vm_protect(
                 self_task,
                 allocated,
                 settings.size as mach_vm_size_t,
                 0,
-                VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE,
+                PROT,
             )
         };
 

src-rust/src/structs/internal/locator_item.rs

@@ -165,12 +165,14 @@ impl LocatorItem {
     /// This function is safe provided that the caller ensures that the buffer is large enough to hold the data.
     /// There is no error thrown if size is insufficient.
     pub unsafe fn append_bytes(&mut self, data: &[u8]) -> usize {
+        disable_write_xor_execute(self.base_address.value as *const u8, data.len());
         let address = self.base_address.value + self.position as usize;
         let data_len = data.len();
 
         std::ptr::copy_nonoverlapping(data.as_ptr(), address as *mut u8, data_len);
         self.position += data_len as u32;
 
+        restore_write_xor_execute(self.base_address.value as *const u8, data.len());
         address
     }
 
@@ -197,9 +199,11 @@ impl LocatorItem {
     where
         T: Copy,
     {
+        disable_write_xor_execute(self.base_address.value as *const u8, data.len());
         let address = (self.base_address.value + self.position as usize) as *mut T;
         *address = data;
         self.position += std::mem::size_of::<T>() as u32;
+        restore_write_xor_execute(self.base_address.value as *const u8, data.len());
         address as usize
     }
 }