Merge pull request #235 from BenjaminRi/infozip-decrypt

Add Info-ZIP password validation

src/read.rs

@@ -4,8 +4,7 @@ use crate::compression::CompressionMethod;
 use crate::crc32::Crc32Reader;
 use crate::result::{InvalidPassword, ZipError, ZipResult};
 use crate::spec;
-use crate::zipcrypto::ZipCryptoReader;
-use crate::zipcrypto::ZipCryptoReaderValid;
+use crate::zipcrypto::{ZipCryptoReader, ZipCryptoReaderValid, ZipCryptoValidator};
 use std::borrow::Cow;
 use std::collections::HashMap;
 use std::io::{self, prelude::*};
@@ -161,6 +160,8 @@ fn find_content<'a>(
 fn make_crypto_reader<'a>(
     compression_method: crate::compression::CompressionMethod,
     crc32: u32,
+    last_modified_time: DateTime,
+    using_data_descriptor: bool,
     reader: io::Take<&'a mut dyn io::Read>,
     password: Option<&[u8]>,
 ) -> ZipResult<Result<CryptoReader<'a>, InvalidPassword>> {
@@ -173,10 +174,17 @@ fn make_crypto_reader<'a>(
 
     let reader = match password {
         None => CryptoReader::Plaintext(reader),
-        Some(password) => match ZipCryptoReader::new(reader, password).validate(crc32)? {
+        Some(password) => {
+            let validator = if using_data_descriptor {
+                ZipCryptoValidator::InfoZipMsdosTime(last_modified_time.timepart())
+            } else {
+                ZipCryptoValidator::PkzipCrc32(crc32)
+            };
+            match ZipCryptoReader::new(reader, password).validate(validator)? {
                 None => return Ok(Err(InvalidPassword)),
                 Some(r) => CryptoReader::ZipCrypto(r),
-        },
+            }
+        }
     };
     Ok(Ok(reader))
 }
@@ -491,7 +499,14 @@ impl<R: Read + io::Seek> ZipArchive<R> {
         }
         let limit_reader = find_content(data, &mut self.reader)?;
 
-        match make_crypto_reader(data.compression_method, data.crc32, limit_reader, password) {
+        match make_crypto_reader(
+            data.compression_method,
+            data.crc32,
+            data.last_modified_time,
+            data.using_data_descriptor,
+            limit_reader,
+            password,
+        ) {
             Ok(Ok(crypto_reader)) => Ok(Ok(ZipFile {
                 crypto_reader: Some(crypto_reader),
                 reader: ZipFileReader::NoReader,
@@ -531,6 +546,7 @@ pub(crate) fn central_header_to_zip_file<R: Read + io::Seek>(
     let flags = reader.read_u16::<LittleEndian>()?;
     let encrypted = flags & 1 == 1;
     let is_utf8 = flags & (1 << 11) != 0;
+    let using_data_descriptor = flags & (1 << 3) != 0;
     let compression_method = reader.read_u16::<LittleEndian>()?;
     let last_mod_time = reader.read_u16::<LittleEndian>()?;
     let last_mod_date = reader.read_u16::<LittleEndian>()?;
@@ -565,6 +581,7 @@ pub(crate) fn central_header_to_zip_file<R: Read + io::Seek>(
         system: System::from_u8((version_made_by >> 8) as u8),
         version_made_by: version_made_by as u8,
         encrypted,
+        using_data_descriptor,
         compression_method: {
             #[allow(deprecated)]
             CompressionMethod::from_u16(compression_method)
@@ -908,6 +925,7 @@ pub fn read_zipfile_from_stream<'a, R: io::Read>(
         system: System::from_u8((version_made_by >> 8) as u8),
         version_made_by: version_made_by as u8,
         encrypted,
+        using_data_descriptor,
         compression_method,
         last_modified_time: DateTime::from_msdos(last_mod_date, last_mod_time),
         crc32,
@@ -943,8 +961,15 @@ pub fn read_zipfile_from_stream<'a, R: io::Read>(
 
     let result_crc32 = result.crc32;
     let result_compression_method = result.compression_method;
-    let crypto_reader =
-        make_crypto_reader(result_compression_method, result_crc32, limit_reader, None)?.unwrap();
+    let crypto_reader = make_crypto_reader(
+        result_compression_method,
+        result_crc32,
+        result.last_modified_time,
+        result.using_data_descriptor,
+        limit_reader,
+        None,
+    )?
+    .unwrap();
 
     Ok(Some(ZipFile {
         data: Cow::Owned(result),

src/types.rs

@@ -216,6 +216,8 @@ pub struct ZipFileData {
     pub version_made_by: u8,
     /// True if the file is encrypted.
     pub encrypted: bool,
+    /// True if the file uses a data-descriptor section
+    pub using_data_descriptor: bool,
     /// Compression method used to store the file
     pub compression_method: crate::compression::CompressionMethod,
     /// Last modified time. This will only have a 2 second precision.
@@ -303,6 +305,7 @@ mod test {
             system: System::Dos,
             version_made_by: 0,
             encrypted: false,
+            using_data_descriptor: false,
             compression_method: crate::compression::CompressionMethod::Stored,
             last_modified_time: DateTime::default(),
             crc32: 0,

src/write.rs

@@ -290,6 +290,7 @@ impl<W: Write + io::Seek> ZipWriter<W> {
                 system: System::Unix,
                 version_made_by: DEFAULT_VERSION,
                 encrypted: false,
+                using_data_descriptor: false,
                 compression_method: options.compression_method,
                 last_modified_time: options.last_modified_time,
                 crc32: raw_values.crc32,

src/zipcrypto.rs

@@ -57,6 +57,11 @@ pub struct ZipCryptoReader<R> {
     keys: ZipCryptoKeys,
 }
 
+pub enum ZipCryptoValidator {
+    PkzipCrc32(u32),
+    InfoZipMsdosTime(u16),
+}
+
 impl<R: std::io::Read> ZipCryptoReader<R> {
     /// Note: The password is `&[u8]` and not `&str` because the
     /// [zip specification](https://pkware.cachefly.net/webdocs/APPNOTE/APPNOTE-6.3.3.TXT)
@@ -81,7 +86,7 @@ impl<R: std::io::Read> ZipCryptoReader<R> {
     /// Read the ZipCrypto header bytes and validate the password.
     pub fn validate(
         mut self,
-        crc32_plaintext: u32,
+        validator: ZipCryptoValidator,
     ) -> Result<Option<ZipCryptoReaderValid<R>>, std::io::Error> {
         // ZipCrypto prefixes a file with a 12 byte header
         let mut header_buf = [0u8; 12];
@@ -90,6 +95,8 @@ impl<R: std::io::Read> ZipCryptoReader<R> {
             *byte = self.keys.decrypt_byte(*byte);
         }
 
+        match validator {
+            ZipCryptoValidator::PkzipCrc32(crc32_plaintext) => {
                 // PKZIP before 2.0 used 2 byte CRC check.
                 // PKZIP 2.0+ used 1 byte CRC check. It's more secure.
                 // We also use 1 byte CRC.
@@ -97,6 +104,21 @@ impl<R: std::io::Read> ZipCryptoReader<R> {
                 if (crc32_plaintext >> 24) as u8 != header_buf[11] {
                     return Ok(None); // Wrong password
                 }
+            }
+            ZipCryptoValidator::InfoZipMsdosTime(last_mod_time) => {
+                // Info-ZIP modification to ZipCrypto format:
+                // If bit 3 of the general purpose bit flag is set
+                // (indicates that the file uses a data-descriptor section),
+                // it uses high byte of 16-bit File Time.
+                // Info-ZIP code probably writes 2 bytes of File Time.
+                // We check only 1 byte.
+
+                if (last_mod_time >> 8) as u8 != header_buf[11] {
+                    return Ok(None); // Wrong password
+                }
+            }
+        }
+
         Ok(Some(ZipCryptoReaderValid { reader: self }))
     }
 }