WIP peloader

2 files changed, 38 insertions, 21 deletions

diff --git a/src/efi/peloader.rs b/src/efi/peloader.rs
index 50993f7..7a3af19 100644
--- a/src/efi/peloader.rs
+++ b/src/efi/peloader.rs
@@ -2,6 +2,7 @@
 // Copyright 2023 Google LLC
 // Author: Ard Biesheuvel <ardb@google.com>
 
+use crate::EFI_PAGE_MASK;
 use crate::efi::memmap;
 use crate::{FileLoader, MemoryType, Placement};
 
@@ -20,6 +21,9 @@ struct DosHeader {
     pe_offset: u32,
 }
 
+#[cfg(target_arch = "aarch64")]
+const ARCH_MACHINE_ID: u16 = 0xaa64;
+
 #[derive(Copy, Clone, Debug)]
 #[repr(C)]
 struct PeHeader {
@@ -142,6 +146,11 @@ impl<'a> PeLoader<'a> {
             pehdr
         );
 
+        if pehdr.machine != ARCH_MACHINE_ID {
+            debug!("Unsupported machine type 0x{:x?}\n", pehdr.machine);
+            return None;
+        }
+
         let section_offset = doshdr.pe_offset + 24 + pehdr.size_of_optional_header as u32;
         let section_count = pehdr.number_of_sections as usize;
         let sections_size = size_of::<PeSection>() * section_count;
@@ -165,19 +174,21 @@ impl<'a> PeLoader<'a> {
         };
         trace!("Section headers: {:x?}\n", sections);
 
-        // Insert a dummy section for the header region
-        sections.push(PeSection {
-            name: [0u8; 8],
-            virtual_size: pehdr.size_of_headers,
-            virtual_address: 0,
-            size_of_raw_data: pehdr.size_of_headers,
-            pointer_to_raw_data: 0,
-            pointer_to_relocations: 0,
-            pointer_to_line_numbers: 0,
-            number_of_relocations: 0,
-            number_of_line_numbers: 0,
-            characteristics: EFI_IMAGE_SCN_MEM_READ,
-        });
+        // Insert a dummy RO+XP section for the header region
+        if pehdr.size_of_headers & EFI_PAGE_MASK as u32 == 0 {
+            sections.push(PeSection {
+                name: [0u8; 8],
+                virtual_size: pehdr.size_of_headers,
+                virtual_address: 0,
+                size_of_raw_data: pehdr.size_of_headers,
+                pointer_to_raw_data: 0,
+                pointer_to_relocations: 0,
+                pointer_to_line_numbers: 0,
+                number_of_relocations: 0,
+                number_of_line_numbers: 0,
+                characteristics: EFI_IMAGE_SCN_MEM_READ,
+            });
+        }
 
         for s in sections.iter() {
             if (s.pointer_to_raw_data | s.size_of_raw_data) & (pehdr.file_alignment - 1) != 0 {
@@ -223,19 +234,25 @@ impl<'a> PeLoader<'a> {
         )?;
 
         for s in self.sections.iter() {
+            let (va, vs, ra, rs) = (
+                s.virtual_address as usize,
+                s.virtual_size as usize,
+                s.pointer_to_raw_data as usize,
+                s.size_of_raw_data as usize,
+            );
             unsafe {
                 self.file_loader
-                    .load_range(
-                        buf[s.virtual_address as usize].as_mut_ptr() as *mut (),
-                        s.pointer_to_raw_data as usize,
-                        s.size_of_raw_data as usize,
-                    )
+                    .load_range(buf[va].as_mut_ptr() as *mut (), ra, vs.min(rs))
                     .ok()?;
             }
-            // TODO zero out remaining space
+            if vs > rs {
+                // Zero init remaining space
+                buf[va+rs..va+vs].fill(MaybeUninit::<u8>::zeroed());
+            }
         }
 
         // TODO apply relocations
+        // TODO free pages on failure
 
         Some(PeImage {
             pe_loader: self,
diff --git a/src/main.rs b/src/main.rs
index 5ad6d02..accd4e9 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -175,7 +175,7 @@ extern "C" fn efilite_main(base: *mut u8, mapped: usize, used: isize, avail: usi
     };
 
     let ldr = fwcfg.get_kernel_loader().expect("No kernel image provided");
-    let pe_ldr = PeLoader::new(&ldr).unwrap();
+    let pe_ldr = PeLoader::new(&ldr).expect("Unsupported kernel image");
     let pe_image = pe_ldr.load(MemoryType::EfiLoaderCode, placement).unwrap();
 
     for s in pe_image.sections() {
@@ -195,7 +195,7 @@ extern "C" fn efilite_main(base: *mut u8, mapped: usize, used: isize, avail: usi
                 idmap.map_range_(&s.0, f);
                 idmap.activate();
             } else {
-                warn!("Cannot remap range {:?}\n", s.0);
+                warn!("Cannot remap range {:x?}\n", s.0);
             }
         }
     }