Fix improper page index handling

bane9 · Aug 29, 2024 · feed287 · feed287
1 parent 141a963
commit feed287
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Showing 4 changed files with 30 additions and 20 deletions.
diff --git a/README.md b/README.md
@@ -124,8 +124,8 @@ The full list is: `test_rvi test_rvm test_rva test_rvmi test_rvsi`
 | Platform        | Compatible | Comments                           |
 |-----------------|------------|------------------------------------|
 | Windows amd64   | ✅         |                                    |
-| Ubuntu amd64    | ✅         | Currently functioning, with intentional memory leakage applied as a temporary workaround.                  |
-| MacOS amd64     | ❌         | Compiles, but MAP_FIXED seems to be unsupported on newer MacOS'                  |
+| Ubuntu amd64    | ✅         |                                    |
+| MacOS amd64     | ❌         | Compiles, but MAP_FIXED seems to be unsupported on newer MacOS' |
 
 ## Note
 

diff --git a/src/frontend/code_pages.rs b/src/frontend/code_pages.rs
@@ -1,40 +1,50 @@
+use hashbrown::HashMap;
+
 use crate::backend::common::HostEncodedInsn;
 use crate::xmem::{self, AllocationError, PageState};
 
 pub struct CodePages {
-    xmem: Vec<xmem::CodePage>,
+    xmem: HashMap<usize, xmem::CodePage>,
+    idx: usize,
 }
 
 impl CodePages {
     pub fn new() -> CodePages {
-        CodePages { xmem: vec![] }
+        CodePages {
+            xmem: HashMap::new(),
+            idx: 0,
+        }
     }
 
     pub fn get_code_page(&mut self, idx: usize) -> &mut xmem::CodePage {
-        self.xmem.get_mut(idx).unwrap()
+        self.xmem.get_mut(&idx).unwrap()
     }
 
     pub fn alloc_code_page(&mut self) -> (&mut xmem::CodePage, usize) {
-        self.xmem.push(xmem::CodePage::new());
-        let idx = self.xmem.len() - 1;
-        (self.xmem.get_mut(idx).unwrap(), idx)
+        let idx = self.idx;
+        self.idx += 1;
+
+        let xmem = xmem::CodePage::new();
+        self.xmem.insert(idx, xmem);
+
+        (self.xmem.get_mut(&idx).unwrap(), idx)
     }
 
     pub fn apply_insn(&mut self, idx: usize, insn: HostEncodedInsn) -> Result<(), AllocationError> {
-        self.xmem[idx].push(insn.as_slice())
+        self.xmem.get_mut(&idx).unwrap().push(insn.as_slice())
     }
 
     pub fn remove_code_page(&mut self, idx: usize) {
-        self.xmem[idx].dealloc();
-        self.xmem.remove(idx);
+        self.xmem.get_mut(&idx).unwrap().dealloc();
+        self.xmem.remove(&idx);
     }
 
     pub fn mark_all_pages(&mut self, state: PageState) {
         for xmem in self.xmem.iter_mut() {
             match state {
-                PageState::ReadWrite => xmem.mark_rw().unwrap(),
-                PageState::ReadExecute => xmem.mark_rx().unwrap(),
-                PageState::Invalid => xmem.mark_invalid().unwrap(),
+                PageState::ReadWrite => xmem.1.mark_rw().unwrap(),
+                PageState::ReadExecute => xmem.1.mark_rx().unwrap(),
+                PageState::Invalid => xmem.1.mark_invalid().unwrap(),
             }
         }
     }

diff --git a/src/frontend/exec_core.rs b/src/frontend/exec_core.rs
@@ -116,8 +116,8 @@ impl ExecCore {
                 ReturnStatus::ReturnAccessViolation => {
                     let mut guest_exception_pc: Option<&InsnMappingData> = None;
                     let likely_offset = BackendCoreImpl::fastmem_violation_likely_offset();
-                    let likely_offset_lower = likely_offset - 32;
-                    let likely_offset_upper = likely_offset + 32;
+                    let likely_offset_lower = likely_offset - 4;
+                    let likely_offset_upper = likely_offset + 4;
 
                     let addr = ret.exception_address as *mut u8;
 

diff --git a/src/xmem/page_allocator.rs b/src/xmem/page_allocator.rs
@@ -141,10 +141,10 @@ pub mod posix_page_allocator {
         }
     }
 
-    pub fn free_pages(_ptr: *mut u8, _npages: usize) {
-        // unsafe {
-        //     libc::munmap(ptr as *mut _, npages * PAGE_SIZE);
-        // }
+    pub fn free_pages(ptr: *mut u8, npages: usize) {
+        unsafe {
+            libc::munmap(ptr as *mut _, npages * PAGE_SIZE);
+        }
     }
 
     pub fn mark_page(