Add a check on .NET executable

Cargo.toml

@@ -1,17 +1,10 @@
 [package]
 name = "memexec"
-version = "0.1.1"
+version = "0.1.2"
 authors = ["iv4n <iv4n.cc@qq.com>"]
 edition = "2018"
-description = "Lib used to load and execute PE (Portable Executable) in memory without ever touching the disk"
+description = "A library for loading and executing PE (Portable Executable) without ever touching the disk"
 git = "https://github.com/eddieivan01/memexec.git"
 license = "GPL-3.0"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[profile.release]
-lto = "fat"
-codegen-units = 1
-opt-level = 3
-panic = "abort"
-incremental = false

README.md

@@ -2,14 +2,14 @@
 
 [![](https://img.shields.io/crates/v/memexec)](https://crates.io/crates/memexec) [![](https://img.shields.io/crates/d/memexec?label=downloads%40crates.io&style=social)](https://crates.io/crates/memexec)
 
-Lib used to load and execute PE (Portable Executable) in memory without ever touching the disk
+A library for loading and executing PE (Portable Executable) without ever touching the disk
 
 # Features
 
-+ Applicable to EXE and DLL
-+ Cross-architecture, applicable to x86 and x86_64
++ Applicable to EXE and DLL (except .NET assembly)
++ Cross-architecture, applicable to x86 and x86-64
 + Zero-dependency
-+ Contains a zero-copy submodule of PE parser
++ Contains a simple, zero-copy PE parser submodule
 
 # Install
 
@@ -76,6 +76,12 @@ let pe = PE::new(&buf);
 println!("{:?}", pe);
 ```
 
+# TODO
+
+- [ ] Replace `LoadLibrary` with calling `load_pe_into_mem` recursively
+
+- [ ] Replace `GetProcAddress` with self-implemented [`LdrpSnapThunk`](https://doxygen.reactos.org/dd/d83/ntdllp_8h.html#ae2196bc7f46cc2a92d36b7c4881ee633), so as to support resolving proc address by `IMAGE_IMPORT_BY_NAME.Hint`
+
 # License
 
 The GPLv3 license

src/lib.rs

@@ -1,6 +1,3 @@
-//! # memexec
-//! Lib used to load and execute PE (Portable Executable) in memory without ever touching the disk
-
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
 #![allow(overflowing_literals)]
@@ -17,7 +14,7 @@ use std::os::raw::c_void;
 
 pub unsafe fn memexec_exe(bs: &[u8]) -> Result<()> {
     let pe = PE::new(bs)?;
-    let loader = ExeLoader::new(&pe).unwrap();
+    let loader = ExeLoader::new(&pe)?;
     Ok(loader.invoke_entry_point())
 }
 
@@ -28,7 +25,7 @@ pub unsafe fn memexec_dll(
     lp_reserved: *const c_void,
 ) -> Result<bool> {
     let pe = PE::new(bs)?;
-    let loader = DllLoader::new(&pe).unwrap();
+    let loader = DllLoader::new(&pe)?;
     Ok(loader.invoke_entry_point(hmod, reason_for_call, lp_reserved))
 }
 

src/peloader/error.rs

@@ -9,6 +9,7 @@ pub enum Error {
     MismatchedArch,
     MismatchedLoader,
     NoEntryPoint,
+    UnsupportedDotNetExecutable,
 }
 
 pub type Result<T> = std::result::Result<T, Error>;

src/peloader/mod.rs

@@ -45,7 +45,7 @@ unsafe fn load_pe_into_mem(pe: &PE) -> Result<*const c_void> {
 
     // Step3: handle base relocataion table
     let reloc_entry = &pe.pe_header.nt_header.get_data_directory()[IMAGE_DIRECTORY_ENTRY_BASERELOC];
-    let image_base_offset = base_addr as isize - pe.pe_header.nt_header.get_image_base() as isize;
+    let image_base_offset = base_addr as usize - pe.pe_header.nt_header.get_image_base() as usize;
     if image_base_offset != 0 && reloc_entry.VirtualAddress != 0 && reloc_entry.Size != 0 {
         let mut reloc_table_ptr =
             base_addr.offset(reloc_entry.VirtualAddress as isize) as *const u8;
@@ -62,7 +62,7 @@ unsafe fn load_pe_into_mem(pe: &PE) -> Result<*const c_void> {
                 if (item >> 12) == IMAGE_REL_BASED {
                     let patch_addr = base_addr
                         .offset(reloc_block.VirtualAddress as isize + (item & 0xfff) as isize)
-                        as *mut isize;
+                        as *mut usize;
                     *patch_addr = *patch_addr + image_base_offset;
                 }
             }
@@ -86,13 +86,14 @@ unsafe fn load_pe_into_mem(pe: &PE) -> Result<*const c_void> {
 
             let dll_name = CStr::from_ptr(base_addr.offset(import_desc.Name as isize) as *const i8)
                 .to_str()?;
+            // TODO: implement loading module by calling self recursively
             let hmod = winapi::load_library(dll_name)?;
 
-            // Whether HNT exists
-            let (mut iat_ptr, mut hnt_ptr) = if import_desc.DUMMYUNIONNAME != 0 {
+            // Whether the ILT (called INT in IDA) exists? (some linkers didn't generate the ILT)
+            let (mut iat_ptr, mut ilt_ptr) = if import_desc.OriginalFirstThunk != 0 {
                 (
                     base_addr.offset(import_desc.FirstThunk as isize) as *mut IMAGE_THUNK_DATA,
-                    base_addr.offset(import_desc.DUMMYUNIONNAME as isize)
+                    base_addr.offset(import_desc.OriginalFirstThunk as isize)
                         as *const IMAGE_THUNK_DATA,
                 )
             } else {
@@ -103,32 +104,33 @@ unsafe fn load_pe_into_mem(pe: &PE) -> Result<*const c_void> {
             };
 
             loop {
-                let thunk_data = *hnt_ptr as isize;
+                let thunk_data = *ilt_ptr as isize;
                 if thunk_data == 0 {
                     break;
                 }
 
                 let proc_addr;
-                if thunk_data & IMAGE_ORDINAL_FLAG == IMAGE_ORDINAL_FLAG {
+                if thunk_data & IMAGE_ORDINAL_FLAG != 0 {
                     // Import by ordinal number
                     proc_addr = winapi::get_proc_address_by_ordinal(hmod, thunk_data & 0xffff)?;
                 } else {
-                    let import_by_name = &*mem::transmute::<PVOID, *const IMAGE_IMPORT_BY_NAME>(
+                    // TODO: implement resolving proc address by `IMAGE_IMPORT_BY_NAME.Hint`
+                    let hint_name_table = &*mem::transmute::<PVOID, *const IMAGE_IMPORT_BY_NAME>(
                         base_addr.offset(thunk_data),
                     );
-                    if 0 == import_by_name.Name {
+                    if 0 == hint_name_table.Name {
                         break;
                     }
 
                     proc_addr = winapi::get_proc_address(
                         hmod,
-                        CStr::from_ptr(&import_by_name.Name as _).to_str()?,
+                        CStr::from_ptr(&hint_name_table.Name as _).to_str()?,
                     )?;
                 }
 
                 *iat_ptr = proc_addr as IMAGE_THUNK_DATA;
                 iat_ptr = iat_ptr.offset(1);
-                hnt_ptr = hnt_ptr.offset(1);
+                ilt_ptr = ilt_ptr.offset(1);
             }
         }
     }
@@ -143,7 +145,7 @@ unsafe fn load_pe_into_mem(pe: &PE) -> Result<*const c_void> {
         winapi::nt_protect_vm(
             &(base_addr.offset(section.VirtualAddress as isize)) as _,
             &size as _,
-            section.protect_value(),
+            section.get_protection(),
         )?;
     }
 
@@ -189,16 +191,20 @@ impl ExeLoader {
     pub unsafe fn new(pe: &PE) -> Result<ExeLoader> {
         check_platform(pe)?;
         if pe.is_dll() {
-            Err(Error::MismatchedLoader)
+            return Err(Error::MismatchedLoader);
+        }
+
+        if pe.is_dot_net() {
+            return Err(Error::UnsupportedDotNetExecutable);
+        }
+
+        let entry_point = pe.pe_header.nt_header.get_address_of_entry_point();
+        if entry_point == 0 {
+            Err(Error::NoEntryPoint)
         } else {
-            let entry_point = pe.pe_header.nt_header.get_address_of_entry_point();
-            if entry_point == 0 {
-                Err(Error::NoEntryPoint)
-            } else {
-                Ok(ExeLoader {
-                    entry_point_va: load_pe_into_mem(pe)?.offset(entry_point),
-                })
-            }
+            Ok(ExeLoader {
+                entry_point_va: load_pe_into_mem(pe)?.offset(entry_point),
+            })
         }
     }
 
@@ -215,16 +221,20 @@ impl DllLoader {
     pub unsafe fn new(pe: &PE) -> Result<DllLoader> {
         check_platform(pe)?;
         if !pe.is_dll() {
-            Err(Error::MismatchedLoader)
+            return Err(Error::MismatchedLoader);
+        }
+
+        if pe.is_dot_net() {
+            return Err(Error::UnsupportedDotNetExecutable);
+        }
+
+        let entry_point = pe.pe_header.nt_header.get_address_of_entry_point();
+        if entry_point == 0 {
+            Err(Error::NoEntryPoint)
         } else {
-            let entry_point = pe.pe_header.nt_header.get_address_of_entry_point();
-            if entry_point == 0 {
-                Err(Error::NoEntryPoint)
-            } else {
-                Ok(DllLoader {
-                    entry_point_va: load_pe_into_mem(pe)?.offset(entry_point),
-                })
-            }
+            Ok(DllLoader {
+                entry_point_va: load_pe_into_mem(pe)?.offset(entry_point),
+            })
         }
     }
 

src/peparser/check.rs

@@ -28,8 +28,9 @@ impl<'a> ImageNtHeaders<'a> {
                     return Err(Error::UnsupportedMachine);
                 }
 
+                // 32-bit .NET assembly may not set IMAGE_FILE_32BIT_MACHINE
                 if h.FileHeader.Characteristics & IMAGE_FILE_EXECUTABLE_IMAGE == 0
-                    || h.FileHeader.Characteristics & IMAGE_FILE_32BIT_MACHINE == 0
+                //    || h.FileHeader.Characteristics & IMAGE_FILE_32BIT_MACHINE == 0
                 {
                     return Err(Error::InvalidFileHeaderCharacteristics);
                 }
@@ -44,7 +45,7 @@ impl<'a> ImageNtHeaders<'a> {
                 }
 
                 if h.FileHeader.Characteristics & IMAGE_FILE_EXECUTABLE_IMAGE == 0
-                    || h.FileHeader.Characteristics & IMAGE_FILE_LARGE_ADDRESS_AWARE == 0
+                //    || h.FileHeader.Characteristics & IMAGE_FILE_LARGE_ADDRESS_AWARE == 0
                 {
                     return Err(Error::InvalidFileHeaderCharacteristics);
                 }

src/peparser/def.rs

@@ -12,7 +12,9 @@ pub(crate) const IMAGE_DOS_SIGNATURE: WORD = 0x5a4d;
 pub(crate) const IMAGE_NT_SIGNATURE: DWORD = 0x00004550;
 
 pub(crate) const IMAGE_FILE_EXECUTABLE_IMAGE: WORD = 0x0002; // File is executable  (i.e. no unresolved external references).
+#[allow(dead_code)]
 pub(crate) const IMAGE_FILE_LARGE_ADDRESS_AWARE: WORD = 0x0020; // App can handle >2gb addresses
+#[allow(dead_code)]
 pub(crate) const IMAGE_FILE_32BIT_MACHINE: WORD = 0x0100; // 32 bit word machine.
 pub(crate) const IMAGE_FILE_DLL: WORD = 0x2000; // File is a DLL.
 
@@ -39,10 +41,19 @@ pub(crate) const IMAGE_NUMBEROF_DIRECTORY_ENTRIES: usize = 16;
 
 pub const IMAGE_DIRECTORY_ENTRY_EXPORT: usize = 0; // Export Directory
 pub const IMAGE_DIRECTORY_ENTRY_IMPORT: usize = 1; // Import Directory
+pub const IMAGE_DIRECTORY_ENTRY_RESOURCE: usize = 2; // Resource Directory
+pub const IMAGE_DIRECTORY_ENTRY_EXCEPTION: usize = 3; // Exception Directory
+pub const IMAGE_DIRECTORY_ENTRY_SECURITY: usize = 4; // Security Directory
 pub const IMAGE_DIRECTORY_ENTRY_BASERELOC: usize = 5; // Base Relocation Table
-pub const IMAGE_DIRECTORY_ENTRY_TLS: usize = 9;
+pub const IMAGE_DIRECTORY_ENTRY_DEBUG: usize = 6; // Debug Directory
+pub const IMAGE_DIRECTORY_ENTRY_ARCHITECTURE: usize = 7; // Architecture Specific Data
+pub const IMAGE_DIRECTORY_ENTRY_GLOBALPTR: usize = 8; // RVA of GP
+pub const IMAGE_DIRECTORY_ENTRY_TLS: usize = 9; // TLS Directory
+pub const IMAGE_DIRECTORY_ENTRY_LOAD_CONFIG: usize = 10; // Load Configuration Directory
+pub const IMAGE_DIRECTORY_ENTRY_BOUND_IMPORT: usize = 11; // Bound Import Directory in headers
 pub const IMAGE_DIRECTORY_ENTRY_IAT: usize = 12; // Import Address Table
 pub const IMAGE_DIRECTORY_ENTRY_DELAY_IMPORT: usize = 13; // Delay Load Import Descriptors
+pub const IMAGE_DIRECTORY_ENTRY_COM_DESCRIPTOR: usize = 14; // COM Runtime descriptor
 
 #[cfg(all(target_arch = "x86_64", target_os = "windows"))]
 pub(crate) const IMAGE_REL_BASED_DIR64: WORD = 10;
@@ -255,7 +266,7 @@ struct_wrapper!(
             DWORD   OriginalFirstThunk;         // RVA to original unbound IAT (PIMAGE_THUNK_DATA)
         }
         */
-        DUMMYUNIONNAME: DWORD,
+        OriginalFirstThunk: DWORD,
         TimeDateStamp: DWORD,
         ForwarderChain: DWORD, // -1 if no forwarders
         Name: DWORD,

src/peparser/mod.rs

@@ -1,10 +1,11 @@
 mod check;
-pub mod def;
-pub mod error;
 mod header;
 mod pe;
 mod section;
 
+pub mod def;
+pub mod error;
+
 pub use header::*;
 pub use pe::*;
 pub use section::*;

src/peparser/pe.rs

@@ -43,4 +43,10 @@ impl<'a> PE<'a> {
             ImageNtHeaders::x64(h) => h.FileHeader.Characteristics & IMAGE_FILE_DLL != 0,
         }
     }
+
+    pub fn is_dot_net(&self) -> bool {
+        let dot_net_desc =
+            &self.pe_header.nt_header.get_data_directory()[IMAGE_DIRECTORY_ENTRY_COM_DESCRIPTOR];
+        dot_net_desc.Size != 0 && dot_net_desc.VirtualAddress != 0
+    }
 }

src/peparser/section.rs

@@ -35,28 +35,28 @@ pub const PAGE_EXECUTE_READ: DWORD = 0x20;
 pub const PAGE_EXECUTE_READWRITE: DWORD = 0x40;
 */
 impl IMAGE_SECTION_HEADER {
+    #[inline]
     pub fn can_read(&self) -> bool {
-        self.Characteristics & IMAGE_SCN_MEM_READ == IMAGE_SCN_MEM_READ
+        self.Characteristics & IMAGE_SCN_MEM_READ != 0
     }
 
+    #[inline]
     pub fn can_write(&self) -> bool {
-        self.Characteristics & IMAGE_SCN_MEM_WRITE == IMAGE_SCN_MEM_WRITE
+        self.Characteristics & IMAGE_SCN_MEM_WRITE != 0
     }
 
+    #[inline]
     pub fn can_exec(&self) -> bool {
-        self.Characteristics & IMAGE_SCN_MEM_EXECUTE == IMAGE_SCN_MEM_EXECUTE
+        self.Characteristics & IMAGE_SCN_MEM_EXECUTE != 0
     }
 
-    pub fn protect_value(&self) -> DWORD {
+    pub fn get_protection(&self) -> DWORD {
         match self.can_exec() {
             true => match self.can_read() {
-                true => {
-                    if self.can_write() {
-                        PAGE_EXECUTE_READWRITE
-                    } else {
-                        PAGE_EXECUTE_READ
-                    }
-                }
+                true => match self.can_write() {
+                    true => PAGE_EXECUTE_READWRITE,
+                    false => PAGE_EXECUTE_READ,
+                },
                 false => PAGE_EXECUTE,
             },
             false => match self.can_read() {