From d51ee6de78da621f72ce3c51b05b2b110b357571 Mon Sep 17 00:00:00 2001
From: Jean-Marie Mineau <jean-marie.mineau@inria.fr>
Date: Fri, 24 Jan 2025 13:39:34 +0100
Subject: [PATCH] experimental feature: reading from zip

---
 androscalpel/src/apk.rs       |  4 +++
 apk_frauder/src/zip_reader.rs | 54 +++++++++++++++++++++++++++++++----
 2 files changed, 52 insertions(+), 6 deletions(-)

diff --git a/androscalpel/src/apk.rs b/androscalpel/src/apk.rs
index e1bddbc..3bc07c7 100644
--- a/androscalpel/src/apk.rs
+++ b/androscalpel/src/apk.rs
@@ -2986,6 +2986,10 @@ impl Apk {
         }
     }
 
+    /// Load all android files in an application.
+    /// This **does not include any .dex file that android would not load.
+    pub fn load_apk() -> Self {}
+
     // TODO: change cache to true when cache invalidation is setup
     /// Add the content of a dex file to the apk.
     ///
diff --git a/apk_frauder/src/zip_reader.rs b/apk_frauder/src/zip_reader.rs
index 440cb14..8a17cb2 100644
--- a/apk_frauder/src/zip_reader.rs
+++ b/apk_frauder/src/zip_reader.rs
@@ -1,13 +1,15 @@
+use std::collections::HashMap;
 use std::io::{Read, Seek, SeekFrom};
 
 use crate::{
-    apk_signing_block::ApkSigningBlock, apk_signing_block::Magic,
+    apk_signing_block::ApkSigningBlock, apk_signing_block::Magic, compression::CompressionMethod,
     end_of_central_directory::EndCentralDirectory,
     end_of_central_directory::Zip64EndCentralDirectory,
     end_of_central_directory::Zip64EndCentralDirectoryLocator, general_purpose_flags, FileHeader,
     FileInfo, LocalFileHeader, Signature,
 };
 use androscalpel_serializer::Serializable;
+use flate2::read::DeflateDecoder;
 
 #[derive(Debug, PartialEq, Eq)]
 pub struct ZipFileReader<T: Read + Seek> {
@@ -285,10 +287,33 @@ impl<T: Read + Seek> ZipFileReader<T> {
 
     pub fn get_bin(&mut self, offset: u64, size: usize) -> Vec<u8> {
         self.data.seek(SeekFrom::Start(offset)).unwrap();
-        let mut data = vec![];
+        let mut data = vec![0u8; size];
+        self.data.read_exact(&mut data).unwrap();
+        /*
         for _ in 0..size {
             data.push(u8::deserialize(&mut self.data).unwrap());
         }
+        */
+        data
+    }
+
+    pub fn read_file_as_vec(&mut self, file: &FileInfo) -> Vec<u8> {
+        let offset = file.get_file_offset();
+        let size_c = file.header.compressed_size as usize;
+        let size = file.header.uncompressed_size as usize;
+        let mut data = vec![0u8; size_c];
+        self.data.seek(SeekFrom::Start(offset)).unwrap();
+        self.data.read_exact(&mut data).unwrap();
+        match file.header.compression_method {
+            CompressionMethod::Stored => {}
+            CompressionMethod::Deflated => {
+                let mut decomp_data = vec![0u8; size];
+                let mut deflater = DeflateDecoder::new(&data[..]);
+                deflater.read_exact(&mut decomp_data).unwrap();
+                data = decomp_data
+            }
+            _ => unimplemented!(),
+        }
         data
     }
 
@@ -297,12 +322,29 @@ impl<T: Read + Seek> ZipFileReader<T> {
     }
 
     pub fn get_classes_file_info(&self) -> Vec<&FileInfo> {
-        // TODO: check for holes: if classesN.dex does not exist,
-        // classesM.dex for M>N are ignored.
-        self.files
+        let files_map: HashMap<String, &FileInfo> = self
+            .files
             .iter()
+            .by_ref()
             .filter(|&file| match_dexfile_name(&file.get_name()))
-            .collect()
+            .map(|file| (file.get_name(), file))
+            .collect();
+        let mut files = vec![];
+        let mut i = 0;
+        loop {
+            let name = if i == 0 {
+                "classes.dex".into()
+            } else {
+                format!("classes{}.dex", i + 1)
+            };
+            if let Some(file) = files_map.get(&name) {
+                files.push(*file);
+            } else {
+                break;
+            }
+            i += 1;
+        }
+        files
     }
 }