add signatures and checksums

androscalpel/Cargo.toml

@@ -9,8 +9,10 @@ name = "androscalpel"
 crate-type = ["cdylib"]
 
 [dependencies]
+adler = "1.0.2"
 androscalpel_serializer = { version = "0.1.0", path = "../androscalpel_serializer" }
 anyhow = { version = "1.0.75", features = ["backtrace"] }
 log = "0.4.20"
 pyo3 = { version = "0.20.0", features = ["anyhow"] }
 pyo3-log = "0.8.3"
+sha1 = "0.10.6"

androscalpel/src/dex_writer.rs

@@ -1,11 +1,13 @@
 //! The structure that generate a .dex from classes.
 
 use std::collections::{HashMap, HashSet, VecDeque};
-use std::io::{Cursor, Write};
-
-use log::debug;
+use std::io;
+use std::io::{Cursor, Seek, SeekFrom, Write};
 
+use adler::Adler32;
 use anyhow::{anyhow, bail, Context};
+use log::debug;
+use sha1::{Digest, Sha1};
 
 use crate::Result;
 use crate::*;
@@ -1898,7 +1900,7 @@ impl DexWriter {
                     annotation_off + 1
                 } else {
                     0
-                }, // TODO: link
+                }, // linked in link_annotations()
             });
         }
 
@@ -2422,57 +2424,58 @@ impl DexWriter {
         self.link_annotations();
 
         debug!("Serialize the dex file");
+        let mut buffer = Cursor::new(Vec::<u8>::new());
         // TODO: compute checksum, hash, ect
-        self.header.serialize(writer)?;
+        self.header.serialize(&mut buffer)?;
         // StringIdItem section
         let mut string_off = self.section_manager.get_offset(Section::StringDataItem);
         for string in self.string_data_list.iter() {
             let str_id = StringIdItem {
                 string_data_off: string_off,
             };
-            str_id.serialize(writer)?;
+            str_id.serialize(&mut buffer)?;
             string_off += string.size() as u32;
         }
         // TypeId section
         for ty in &self.type_ids_list {
-            ty.serialize(writer)?;
+            ty.serialize(&mut buffer)?;
         }
         // ProtoId section
         for proto in &self.proto_ids_list {
-            proto.serialize(writer)?;
+            proto.serialize(&mut buffer)?;
         }
         // FieldIdItem section
         for field_id in &self.field_ids_list {
-            field_id.serialize(writer)?;
+            field_id.serialize(&mut buffer)?;
         }
         // MethodIdItem section
         for method_id in &self.method_ids_list {
-            method_id.serialize(writer)?;
+            method_id.serialize(&mut buffer)?;
         }
         // ClassDefItem section
         for class_def in &self.class_defs_list {
-            class_def.serialize(writer)?;
+            class_def.serialize(&mut buffer)?;
         }
         // CallSiteIdItem, data are inserted as encoded array item later
         for call_site_id in &self.call_site_ids {
-            call_site_id.serialize(writer)?;
+            call_site_id.serialize(&mut buffer)?;
         }
 
         // MethodHandleItem section
         for handle in &self.method_handles {
-            handle.serialize(writer)?;
+            handle.serialize(&mut buffer)?;
         }
         // MapList
-        self.map_list.serialize(writer)?;
+        self.map_list.serialize(&mut buffer)?;
         // TypeList,
         let mut offset = 0; // the sections are always aligned until the type_lists
         for (list, _) in &self.type_lists_with_offset {
             while offset % 4 != 0 {
                 offset += 1;
-                0u8.serialize(writer)?;
+                0u8.serialize(&mut buffer)?;
             }
             offset += list.size();
-            list.serialize(writer)?;
+            list.serialize(&mut buffer)?;
         }
         // The next section requires alignment to 4
         while offset % 4 != 0 {
@@ -2482,41 +2485,61 @@ impl DexWriter {
         }
         // AnnotationSetRefList section
         for list in &self.annotation_set_lists {
-            list.serialize(writer)?;
+            list.serialize(&mut buffer)?;
         }
         // AnnotationSetItem section
         for set in &self.annotation_set_items {
-            set.serialize(writer)?;
+            set.serialize(&mut buffer)?;
         }
         // ClassDataItem section
         for data in &self.class_data_list {
-            data.serialize(writer)?;
+            data.serialize(&mut buffer)?;
         }
         // CodeItem section
         for code_item in &self.code_items {
-            code_item.serialize(writer)?
+            code_item.serialize(&mut buffer)?
         }
         for string in &self.string_data_list {
-            string.serialize(writer)?;
+            string.serialize(&mut buffer)?;
         }
         // DebugInfoItem section
         for debug_info in &self.debug_info_items {
-            debug_info.serialize(writer)?;
+            debug_info.serialize(&mut buffer)?;
         }
         // AnnotationItem section
         for annot in &self.annotation_items {
-            annot.serialize(writer)?;
+            annot.serialize(&mut buffer)?;
         }
         // EncodedArrayItem section
         for array in &self.encoded_array_items {
-            array.serialize(writer)?;
+            array.serialize(&mut buffer)?;
         }
         // AnnotationsDirectoryItem section
         for dir in &self.annotations_directory_items {
-            dir.serialize(writer)?;
+            dir.serialize(&mut buffer)?;
         }
         // TODO: HiddenapiClassDataItem,
 
+        // compute signature
+        buffer.seek(SeekFrom::Start(8 + 4 + 20))?;
+        let mut hasher = Sha1::new();
+        io::copy(&mut buffer, &mut hasher)?;
+        self.header.signature = hasher.finalize().into();
+        buffer.rewind()?;
+        self.header.serialize(&mut buffer)?;
+
+        // Compute checksum
+        //buffer.seek(SeekFrom::Start(8 + 4))?;
+        let mut adler = Adler32::new();
+        adler.write_slice(&buffer.get_ref()[8 + 4..]);
+        self.header.checksum = adler.checksum();
+        buffer.rewind()?;
+        self.header.serialize(&mut buffer)?;
+
+        // copy buffer to output
+        buffer.rewind()?;
+        io::copy(&mut buffer, writer)?;
+
         Ok(())
     }