parse basic file header

apk_frauder/src/main.rs

@@ -7,6 +7,122 @@ use androscalpel_serializer::{ReadSeek, Result, Serializable};
 //struct Signature(pub [u8; 4]);
 struct Signature(pub u32);
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+struct FileHeader {
+    // signature: Signature(0x02014b50)
+    version_made_by: u16,
+    version_needed_to_extract: u16,
+    general_purpose_flag: u16,
+    compression_method: u16,
+    last_mod_file_time: u16,
+    last_mod_file_data: u16,
+    crc_32: u32,
+    compressed_size: u32,
+    uncompressed_size: u32,
+    // file_name_length: u16,
+    // extra_field_length: u16,
+    // file_comment_length: u16,
+    disk_number_start: u16,
+    internal_file_attributes: u16,
+    external_file_attributes: u32,
+    offset_local_header: u32,
+    file_name: Vec<u8>,
+    extra_field: Vec<u8>, // TODO: zip64
+    file_comment: Vec<u8>,
+}
+
+impl Serializable for FileHeader {
+    fn serialize(&self, output: &mut dyn Write) -> Result<()> {
+        Self::SIGNATURE.serialize(output)?;
+        self.version_made_by.serialize(output)?;
+        self.version_needed_to_extract.serialize(output)?;
+        self.general_purpose_flag.serialize(output)?;
+        self.compression_method.serialize(output)?;
+        self.last_mod_file_time.serialize(output)?;
+        self.last_mod_file_data.serialize(output)?;
+        self.crc_32.serialize(output)?;
+        self.compressed_size.serialize(output)?;
+        self.uncompressed_size.serialize(output)?;
+        (self.file_name.len() as u16).serialize(output)?;
+        (self.extra_field.len() as u16).serialize(output)?;
+        (self.file_comment.len() as u16).serialize(output)?;
+        self.disk_number_start.serialize(output)?;
+        self.internal_file_attributes.serialize(output)?;
+        self.external_file_attributes.serialize(output)?;
+        self.offset_local_header.serialize(output)?;
+        for c in &self.file_name {
+            c.serialize(output)?;
+        }
+        for c in &self.extra_field {
+            c.serialize(output)?;
+        }
+        for c in &self.file_comment {
+            c.serialize(output)?;
+        }
+        Ok(())
+    }
+
+    fn deserialize(input: &mut dyn ReadSeek) -> Result<Self> {
+        let signature = Signature::deserialize(input)?;
+        assert_eq!(signature, Self::SIGNATURE); // TODO
+        let version_made_by = u16::deserialize(input)?;
+        let version_needed_to_extract = u16::deserialize(input)?;
+        let general_purpose_flag = u16::deserialize(input)?;
+        let compression_method = u16::deserialize(input)?;
+        let last_mod_file_time = u16::deserialize(input)?;
+        let last_mod_file_data = u16::deserialize(input)?;
+        let crc_32 = u32::deserialize(input)?;
+        let compressed_size = u32::deserialize(input)?;
+        let uncompressed_size = u32::deserialize(input)?;
+        let file_name_length = u16::deserialize(input)?;
+        let extra_field_length = u16::deserialize(input)?;
+        let file_comment_length = u16::deserialize(input)?;
+        let disk_number_start = u16::deserialize(input)?;
+        let internal_file_attributes = u16::deserialize(input)?;
+        let external_file_attributes = u32::deserialize(input)?;
+        let offset_local_header = u32::deserialize(input)?;
+        let mut file_name = vec![];
+        let mut extra_field = vec![];
+        let mut file_comment = vec![];
+        for _ in 0..file_name_length {
+            file_name.push(u8::deserialize(input)?);
+        }
+        for _ in 0..extra_field_length {
+            extra_field.push(u8::deserialize(input)?);
+        }
+        for _ in 0..file_comment_length {
+            file_comment.push(u8::deserialize(input)?);
+        }
+        Ok(Self {
+            version_made_by,
+            version_needed_to_extract,
+            general_purpose_flag,
+            compression_method,
+            last_mod_file_time,
+            last_mod_file_data,
+            crc_32,
+            compressed_size,
+            uncompressed_size,
+            disk_number_start,
+            internal_file_attributes,
+            external_file_attributes,
+            offset_local_header,
+            file_name,
+            extra_field,
+            file_comment,
+        })
+    }
+
+    fn size(&self) -> usize {
+        Self::MIN_SIZE + self.file_name.len() + self.extra_field.len() + self.file_comment.len()
+    }
+}
+
+impl FileHeader {
+    const SIGNATURE: Signature = Signature(0x02014b50);
+    const MIN_SIZE: usize = 4 + 6 * 2 + 4 * 3 + 5 * 2 + 4 * 2;
+}
+
 #[derive(Debug, Clone, PartialEq, Eq)]
 struct Zip64EndCentralDirectory {
     // signature: Signature
@@ -164,7 +280,8 @@ impl Serializable for EndCentralDirectory {
 
 struct ZipFile<T: Read + Seek> {
     end_of_central_directory: EndCentralDirectory,
-    end_of_central_directory_off: u64,
+    zip64_end_of_central_directory: Option<Zip64EndCentralDirectory>,
+    files: Vec<FileHeader>,
     data: T,
 }
 
@@ -183,7 +300,7 @@ impl<T: Read + Seek> ZipFile<T> {
             ))
             .unwrap();
         let zip64_ecd_locator = Zip64EndCentralDirectoryLocator::deserialize(&mut reader).ok();
-        if let Some(zip64_ecd_locator) = zip64_ecd_locator {
+        let zip64_end_of_central_directory = if let Some(zip64_ecd_locator) = zip64_ecd_locator {
             assert_eq!(
                 zip64_ecd_locator.disk_number_of_zip64_end_central_directory_start,
                 0
@@ -195,12 +312,93 @@ impl<T: Read + Seek> ZipFile<T> {
             reader.seek(SeekFrom::Start(zip64_edc_record_off)).unwrap();
             let zip64_edc_reccord = Zip64EndCentralDirectory::deserialize(&mut reader).ok();
             println!("{zip64_edc_reccord:#?}");
-        }
+            zip64_edc_reccord
+        } else {
+            None
+        };
 
-        Self {
+        // At this point python's ziplib recompute the location of the central directory from the
+        // location of the end of central directory in case the zip was concanated after a file.
+        // We probably don't need that for now.
+        let mut zip_file = Self {
             end_of_central_directory,
-            end_of_central_directory_off,
+            zip64_end_of_central_directory,
             data: reader,
+            files: vec![],
+        };
+        zip_file
+            .data
+            .seek(SeekFrom::Start(zip_file.get_ed_offset()))
+            .unwrap();
+
+        let mut size_read = 0;
+        let cd_size = zip_file.get_ed_size();
+        while size_read < cd_size {
+            let file_header = FileHeader::deserialize(&mut zip_file.data).unwrap();
+            size_read += file_header.size() as u64;
+            zip_file.files.push(file_header);
+        }
+        assert_eq!(size_read, cd_size);
+        for f in &zip_file.files {
+            println!("{f:?}");
+        }
+        zip_file
+    }
+
+    /*
+    fn is_zip64(&self) -> bool {
+        self.zip64_end_of_central_directory.is_some()
+    }
+    */
+
+    fn get_disk_num(&self) -> u32 {
+        if let Some(zip64_end_of_central_directory) = &self.zip64_end_of_central_directory {
+            zip64_end_of_central_directory.number_of_this_disk
+        } else {
+            self.end_of_central_directory.disk_number as u32
+        }
+    }
+
+    fn get_disk_ed_start(&self) -> u32 {
+        if let Some(zip64_end_of_central_directory) = &self.zip64_end_of_central_directory {
+            zip64_end_of_central_directory.disk_number_of_central_directory_start
+        } else {
+            self.end_of_central_directory
+                .disk_number_of_central_directory_start as u32
+        }
+    }
+
+    fn get_number_entries_on_disk(&self) -> u64 {
+        if let Some(zip64_end_of_central_directory) = &self.zip64_end_of_central_directory {
+            zip64_end_of_central_directory.number_entry_in_central_directory_on_this_disk
+        } else {
+            self.end_of_central_directory
+                .number_of_entries_in_central_directory_on_disk as u64
+        }
+    }
+
+    fn get_number_entries(&self) -> u64 {
+        if let Some(zip64_end_of_central_directory) = &self.zip64_end_of_central_directory {
+            zip64_end_of_central_directory.number_entry_in_central_directory
+        } else {
+            self.end_of_central_directory
+                .number_of_entries_in_central_directory as u64
+        }
+    }
+
+    fn get_ed_size(&self) -> u64 {
+        if let Some(zip64_end_of_central_directory) = &self.zip64_end_of_central_directory {
+            zip64_end_of_central_directory.size_of_central_directory
+        } else {
+            self.end_of_central_directory.size_central_directory as u64
+        }
+    }
+
+    fn get_ed_offset(&self) -> u64 {
+        if let Some(zip64_end_of_central_directory) = &self.zip64_end_of_central_directory {
+            zip64_end_of_central_directory.offset_central_directory
+        } else {
+            self.end_of_central_directory.offset_central_directory as u64
         }
     }