将解密文件读入 ZipInputStream 有时会截断第一个文件
Reading a decrypted file into a ZipInputStream truncates first file sometimes
我正在开发一个 e-reader 应用程序（使用 skyepub），它基本上将加密书籍下载到文件系统中（并且它保存的是数据库中的解密密钥），并且当用户尝试阅读它会将书加载到内存中并对其进行解密。
问题是有些书的第一章是 t运行（epub 书实际上是 zip 文件，每一章都是一个单独的文件）。这导致了这个可怕的错误：
this XML file does not appear to have any style information associated with it. The document tree is shown below
我试过的
我已经确认加密的书已正确下载，b/c 如果我将文件复制到我的桌面（从我的 root android）和 运行 此命令它：
openssl aes-192-cbc -d -K *** -iv *** -in test.epub.encrypted -out test.epub
它工作得很好。但是，如果我几乎尝试使用以下 android 代码
做同样的事情
public ContentData getContentData(String baseDirectory, String contentPath) {
if( contentPath.startsWith("/fonts/")) {
... // handle font suff
}
int secondSlash = contentPath.indexOf('/', 1);
if( secondSlash == -1) return null;
String bookEditionID = contentPath.substring(1,secondSlash);
String zipEntryName = contentPath.substring(secondSlash+1);
final ContentData data = new ContentData();
try {
InputStream stream = dbUtil.getBookStream(bookEditionID);
if( stream == null) return null;
final ZipInputStream zip = new ZipInputStream(stream);
ZipEntry entry;
do {
entry = zip.getNextEntry();
Log.e("Abjjad","looping through entry: "+entry);
if( entry == null) {
zip.close();
return null;
}
} while( !entry.getName().equals(zipEntryName));
Log.e("debug","going through data with entry: " +entry+", contentLength: "+entry.getSize());
见方法dbUtil.getBookStream:
public InputStream getBookStream( String bookEditionId) {
BookInfo book = getBookInfo(bookEditionId);
InputStream origStream = null;
try {
// Open the downloaded ePub
origStream = openFileInput(bookEditionId + ".epub");
// De-obfuscate the key
SecretKeySpec sks = getObfuscationKeySpec(bookEditionId);
Cipher c = Cipher.getInstance("AES/ECB/PKCS5Padding", "BC");
c.init(Cipher.DECRYPT_MODE, sks);
byte[] decodedBytes = c.doFinal(Base64.decode(book.decryptionKey, Base64.DEFAULT));
String keyPair = new String(decodedBytes);
// Split the key and parse into binary
int separator = keyPair.indexOf(':');
byte[] key = DatatypeConverter.parseHexBinary(keyPair.substring(0, separator));
byte[] iv = DatatypeConverter.parseHexBinary(keyPair.substring(separator + 1));
c = Cipher.getInstance("AES/CBC/PKCS7Padding","BC");
c.init(Cipher.DECRYPT_MODE, new SecretKeySpec(key,"AES"), new IvParameterSpec(iv));
return new CipherInputStream(origStream, c);
} catch( Exception e) {
try {
if (origStream != null) origStream.close();
} catch( Exception x) {}
return null;
}
}
然后是第一个代码块中entry.getSize()returns-1的日志。
奖金（适用于 iOS！）
我们在 iOS 中编写了相同的代码，并且它运行完美（在同一本书上）：
+ (NSData *)encryptKey:(NSString *)key ivParam:(NSString *)iv bookId:(NSString *)bookId
{
NSString *keyPair = [NSString stringWithFormat:@"%@:%@", key, iv];
NSString *secret = [self getObfuscationSecretWithValue:bookId];
NSData *data = [keyPair dataUsingEncoding:NSASCIIStringEncoding];
char keyPtr[kCCKeySizeAES128];
bzero(keyPtr, sizeof(keyPtr));
[[NSData dataWithHexString:secret] getBytes:keyPtr length:sizeof(keyPtr)];
NSUInteger dataLength = [data length];
size_t bufferSize = dataLength + kCCBlockSizeAES128;
void *buffer = malloc(bufferSize);
size_t numBytesEncrypted;
CCCryptorStatus status = CCCrypt(kCCEncrypt, kCCAlgorithmAES, kCCOptionPKCS7Padding | kCCOptionECBMode, keyPtr, kCCKeySizeAES128,
NULL,
[data bytes], [data length],
buffer, bufferSize, &numBytesEncrypted);
if (status == kCCSuccess) {
return [NSData dataWithBytes:buffer length:numBytesEncrypted];
}
else {
free(buffer);
return nil;
}
}
更新
我注意到这个 t运行cation 只在阅读目录后发生（这看起来像上面的 last 章节？）.. 从日志：
:::::::::::::::::::::::::::::::
getInputStream: /24748681/OEBPS/toc.ncx
:::::::::::::::::::::::::::::::
looping through entry: mimetype
looping through entry: OEBPS/hayat-ghayr.html
looping through entry: OEBPS/content.opf
looping through entry: OEBPS/images/978-614-425-313-7-hayat-ghayr-cover.png
looping through entry: OEBPS/images/978-614-425-313-7-hayat_fmt.png
looping through entry: OEBPS/template.css
looping through entry: OEBPS/hayat-ghayr-2.html
looping through entry: OEBPS/hayat-ghayr-1.html
looping through entry: OEBPS/hayat-ghayr-3.html
looping through entry: OEBPS/hayat-ghayr-4.html
looping through entry: OEBPS/hayat-ghayr-5.html
looping through entry: OEBPS/hayat-ghayr-6.html
looping through entry: OEBPS/hayat-ghayr-7.html
looping through entry: OEBPS/hayat-ghayr-8.html
looping through entry: OEBPS/hayat-ghayr-9.html
looping through entry: OEBPS/hayat-ghayr-10.html
looping through entry: OEBPS/hayat-ghayr-11.html
looping through entry: OEBPS/hayat-ghayr-12.html
looping through entry: OEBPS/hayat-ghayr-13.html
looping through entry: OEBPS/hayat-ghayr-14.html
looping through entry: OEBPS/hayat-ghayr-15.html
looping through entry: OEBPS/hayat-ghayr-16.html
looping through entry: OEBPS/hayat-ghayr-17.html
looping through entry: OEBPS/hayat-ghayr-18.html
looping through entry: OEBPS/hayat-ghayr-19.html
looping through entry: OEBPS/hayat-ghayr-20.html
looping through entry: OEBPS/hayat-ghayr-21.html
looping through entry: OEBPS/hayat-ghayr-22.html
looping through entry: META-INF/container.xml
looping through entry: OEBPS/images/277.png
looping through entry: OEBPS/toc.ncx
going through data with entry: OEBPS/toc.ncx, contentLength: 5549
returning data
:::::::::::::::::::::::::::::::
getInputStream: /24748681/OEBPS/hayat-ghayr.html
:::::::::::::::::::::::::::::::
looping through entry: mimetype
looping through entry: OEBPS/hayat-ghayr.html
going through data with entry: OEBPS/hayat-ghayr.html, contentLength: -1
returning data
根据 the docs，如果大小未知，getSize() 可能 return -1。这肯定发生在某些 zip 文件中。在这些情况下，您需要阅读整个条目以确定其未压缩的大小。
分析
红鲱鱼
首先，整个加密解密的事情是一个红色的鲱鱼..简单地复制 same epub/zip 文件并使用相同的代码读取它会产生相同的结果页面.. 所以这是 zip 文件本身的问题，而不是它的解密问题
Zip 文档
如 java 文档中所述，如果内容未知（这正是此处发生的情况），读取 zip 文件实际上可以 return -1.. 事实上，我们得到了 相同的 zip 文件，将其解压缩（在命令行上），然后使用更高的压缩级别重新压缩它，如下所示：
zip -9 -r filename.epub *
然后我们将相同的 zip 文件提供给现有代码，它完美地工作了！
解决方案
所以这是最终有效的代码：
try {
InputStream stream = abjjadDb.getBookStream(bookEditionID);
if( stream == null) return null;
final ZipInputStream zip = new ZipInputStream(stream);
ZipEntry entry;
do {
entry = zip.getNextEntry();
if( entry == null) {
zip.close();
return null;
}
} while( !entry.getName().equals(zipEntryName));
data.contentLength = entry.getSize();
data.lastModified = entry.getTime();
data.contentPath = contentPath;
InputStream s = zip;
if( data.contentLength == -1) {
Log.e("demo",new Object(){}.getClass().getEnclosingMethod().getName()+":: entry \""+entry+"\" has contentLength -1, so we will work around");
ByteArrayOutputStream buffer = new ByteArrayOutputStream();
int nRead;
// use buf to store data from the zip file entry in fixed size
byte[] buf = new byte[4096];
while ((nRead = zip.read(buf)) != -1) {
// dump that data into buffer, which is a growing buffer
buffer.write(buf, 0, nRead);
}
buffer.flush();
byte[] finalBuffer = buffer.toByteArray();
Log.e("demo",new Object(){}.getClass().getEnclosingMethod().getName()+":: entry \""+entry+"\" final data length: "+finalBuffer.length);
data.contentLength = finalBuffer.length;
s = new ByteArrayInputStream(finalBuffer);
}
final InputStream finalStream = s;
日志给了我们这个
getContentData:: entry "OEBPS/hayat-ghayr.html" has contentLength -1, so we will work around
getContentData:: entry "OEBPS/hayat-ghayr.html" final data length: 2378
getContentData:: entry "OEBPS/hayat-ghayr.html" has contentLength -1, so we will work around
getContentData:: entry "OEBPS/hayat-ghayr.html" final data length: 2378
有趣的是..如果我们在命令行中运行，那么该大小与该文件hayat-ghayr的实际内容长度完全匹配：
$ unzip -l b17c024e-89f1-42f7-a546-91d46610cedb.epub
Archive: b17c024e-89f1-42f7-a546-91d46610cedb.epub
Length Date Time Name
-------- ---- ---- ----
20 01-27-12 11:17 mimetype
2378 04-20-12 10:12 OEBPS/hayat-ghayr.html
6436 02-06-12 11:06 OEBPS/content.opf
112579 01-27-12 11:25 OEBPS/images/978-614-425-313-7-hayat-ghayr-cover.png
182575 01-27-12 11:25 OEBPS/images/978-614-425-313-7-hayat_fmt.png
7757 01-27-12 11:21 OEBPS/template.css
5643 01-27-12 11:18 OEBPS/hayat-ghayr-2.html
20144 01-27-12 11:17 OEBPS/hayat-ghayr-1.html
65543 01-27-12 11:17 OEBPS/hayat-ghayr-3.html
59434 01-27-12 11:17 OEBPS/hayat-ghayr-4.html
66768 01-27-12 11:17 OEBPS/hayat-ghayr-5.html
49117 01-27-12 11:17 OEBPS/hayat-ghayr-6.html
65346 01-27-12 11:17 OEBPS/hayat-ghayr-7.html
74196 01-27-12 11:17 OEBPS/hayat-ghayr-8.html
73998 01-27-12 11:17 OEBPS/hayat-ghayr-9.html
61031 01-27-12 11:17 OEBPS/hayat-ghayr-10.html
68297 01-27-12 11:17 OEBPS/hayat-ghayr-11.html
72084 01-27-12 11:17 OEBPS/hayat-ghayr-12.html
2386 01-27-12 11:17 OEBPS/hayat-ghayr-13.html
61132 01-27-12 11:17 OEBPS/hayat-ghayr-14.html
46320 01-27-12 11:17 OEBPS/hayat-ghayr-15.html
32673 01-27-12 11:17 OEBPS/hayat-ghayr-16.html
88584 01-27-12 11:17 OEBPS/hayat-ghayr-17.html
56474 01-27-12 11:17 OEBPS/hayat-ghayr-18.html
52840 01-27-12 11:17 OEBPS/hayat-ghayr-19.html
80022 01-27-12 11:17 OEBPS/hayat-ghayr-20.html
50781 01-27-12 11:17 OEBPS/hayat-ghayr-21.html
2765 01-27-12 11:17 OEBPS/hayat-ghayr-22.html
265 01-27-12 11:17 META-INF/container.xml
54942 01-27-12 11:17 OEBPS/images/277.png
5549 01-27-12 11:17 OEBPS/toc.ncx
1072 03-23-12 13:28 iTunesMetadata.plist
-------- -------
1529151 32 files
我正在开发一个 e-reader 应用程序（使用 skyepub），它基本上将加密书籍下载到文件系统中（并且它保存的是数据库中的解密密钥），并且当用户尝试阅读它会将书加载到内存中并对其进行解密。
问题是有些书的第一章是 t运行（epub 书实际上是 zip 文件，每一章都是一个单独的文件）。这导致了这个可怕的错误：
this XML file does not appear to have any style information associated with it. The document tree is shown below
我试过的
我已经确认加密的书已正确下载，b/c 如果我将文件复制到我的桌面（从我的 root android）和 运行 此命令它：
openssl aes-192-cbc -d -K *** -iv *** -in test.epub.encrypted -out test.epub
它工作得很好。但是，如果我几乎尝试使用以下 android 代码
做同样的事情public ContentData getContentData(String baseDirectory, String contentPath) {
if( contentPath.startsWith("/fonts/")) {
... // handle font suff
}
int secondSlash = contentPath.indexOf('/', 1);
if( secondSlash == -1) return null;
String bookEditionID = contentPath.substring(1,secondSlash);
String zipEntryName = contentPath.substring(secondSlash+1);
final ContentData data = new ContentData();
try {
InputStream stream = dbUtil.getBookStream(bookEditionID);
if( stream == null) return null;
final ZipInputStream zip = new ZipInputStream(stream);
ZipEntry entry;
do {
entry = zip.getNextEntry();
Log.e("Abjjad","looping through entry: "+entry);
if( entry == null) {
zip.close();
return null;
}
} while( !entry.getName().equals(zipEntryName));
Log.e("debug","going through data with entry: " +entry+", contentLength: "+entry.getSize());
见方法dbUtil.getBookStream:
public InputStream getBookStream( String bookEditionId) {
BookInfo book = getBookInfo(bookEditionId);
InputStream origStream = null;
try {
// Open the downloaded ePub
origStream = openFileInput(bookEditionId + ".epub");
// De-obfuscate the key
SecretKeySpec sks = getObfuscationKeySpec(bookEditionId);
Cipher c = Cipher.getInstance("AES/ECB/PKCS5Padding", "BC");
c.init(Cipher.DECRYPT_MODE, sks);
byte[] decodedBytes = c.doFinal(Base64.decode(book.decryptionKey, Base64.DEFAULT));
String keyPair = new String(decodedBytes);
// Split the key and parse into binary
int separator = keyPair.indexOf(':');
byte[] key = DatatypeConverter.parseHexBinary(keyPair.substring(0, separator));
byte[] iv = DatatypeConverter.parseHexBinary(keyPair.substring(separator + 1));
c = Cipher.getInstance("AES/CBC/PKCS7Padding","BC");
c.init(Cipher.DECRYPT_MODE, new SecretKeySpec(key,"AES"), new IvParameterSpec(iv));
return new CipherInputStream(origStream, c);
} catch( Exception e) {
try {
if (origStream != null) origStream.close();
} catch( Exception x) {}
return null;
}
}
然后是第一个代码块中entry.getSize()returns-1的日志。
奖金（适用于 iOS！）
我们在 iOS 中编写了相同的代码，并且它运行完美（在同一本书上）：
+ (NSData *)encryptKey:(NSString *)key ivParam:(NSString *)iv bookId:(NSString *)bookId
{
NSString *keyPair = [NSString stringWithFormat:@"%@:%@", key, iv];
NSString *secret = [self getObfuscationSecretWithValue:bookId];
NSData *data = [keyPair dataUsingEncoding:NSASCIIStringEncoding];
char keyPtr[kCCKeySizeAES128];
bzero(keyPtr, sizeof(keyPtr));
[[NSData dataWithHexString:secret] getBytes:keyPtr length:sizeof(keyPtr)];
NSUInteger dataLength = [data length];
size_t bufferSize = dataLength + kCCBlockSizeAES128;
void *buffer = malloc(bufferSize);
size_t numBytesEncrypted;
CCCryptorStatus status = CCCrypt(kCCEncrypt, kCCAlgorithmAES, kCCOptionPKCS7Padding | kCCOptionECBMode, keyPtr, kCCKeySizeAES128,
NULL,
[data bytes], [data length],
buffer, bufferSize, &numBytesEncrypted);
if (status == kCCSuccess) {
return [NSData dataWithBytes:buffer length:numBytesEncrypted];
}
else {
free(buffer);
return nil;
}
}
更新
我注意到这个 t运行cation 只在阅读目录后发生（这看起来像上面的 last 章节？）.. 从日志：
:::::::::::::::::::::::::::::::
getInputStream: /24748681/OEBPS/toc.ncx
:::::::::::::::::::::::::::::::
looping through entry: mimetype
looping through entry: OEBPS/hayat-ghayr.html
looping through entry: OEBPS/content.opf
looping through entry: OEBPS/images/978-614-425-313-7-hayat-ghayr-cover.png
looping through entry: OEBPS/images/978-614-425-313-7-hayat_fmt.png
looping through entry: OEBPS/template.css
looping through entry: OEBPS/hayat-ghayr-2.html
looping through entry: OEBPS/hayat-ghayr-1.html
looping through entry: OEBPS/hayat-ghayr-3.html
looping through entry: OEBPS/hayat-ghayr-4.html
looping through entry: OEBPS/hayat-ghayr-5.html
looping through entry: OEBPS/hayat-ghayr-6.html
looping through entry: OEBPS/hayat-ghayr-7.html
looping through entry: OEBPS/hayat-ghayr-8.html
looping through entry: OEBPS/hayat-ghayr-9.html
looping through entry: OEBPS/hayat-ghayr-10.html
looping through entry: OEBPS/hayat-ghayr-11.html
looping through entry: OEBPS/hayat-ghayr-12.html
looping through entry: OEBPS/hayat-ghayr-13.html
looping through entry: OEBPS/hayat-ghayr-14.html
looping through entry: OEBPS/hayat-ghayr-15.html
looping through entry: OEBPS/hayat-ghayr-16.html
looping through entry: OEBPS/hayat-ghayr-17.html
looping through entry: OEBPS/hayat-ghayr-18.html
looping through entry: OEBPS/hayat-ghayr-19.html
looping through entry: OEBPS/hayat-ghayr-20.html
looping through entry: OEBPS/hayat-ghayr-21.html
looping through entry: OEBPS/hayat-ghayr-22.html
looping through entry: META-INF/container.xml
looping through entry: OEBPS/images/277.png
looping through entry: OEBPS/toc.ncx
going through data with entry: OEBPS/toc.ncx, contentLength: 5549
returning data
:::::::::::::::::::::::::::::::
getInputStream: /24748681/OEBPS/hayat-ghayr.html
:::::::::::::::::::::::::::::::
looping through entry: mimetype
looping through entry: OEBPS/hayat-ghayr.html
going through data with entry: OEBPS/hayat-ghayr.html, contentLength: -1
returning data
根据 the docs，如果大小未知，getSize() 可能 return -1。这肯定发生在某些 zip 文件中。在这些情况下，您需要阅读整个条目以确定其未压缩的大小。
分析
红鲱鱼
首先，整个加密解密的事情是一个红色的鲱鱼..简单地复制 same epub/zip 文件并使用相同的代码读取它会产生相同的结果页面.. 所以这是 zip 文件本身的问题，而不是它的解密问题
Zip 文档
如 java 文档中所述，如果内容未知（这正是此处发生的情况），读取 zip 文件实际上可以 return -1.. 事实上，我们得到了 相同的 zip 文件，将其解压缩（在命令行上），然后使用更高的压缩级别重新压缩它，如下所示：
zip -9 -r filename.epub *
然后我们将相同的 zip 文件提供给现有代码，它完美地工作了！
解决方案
所以这是最终有效的代码：
try {
InputStream stream = abjjadDb.getBookStream(bookEditionID);
if( stream == null) return null;
final ZipInputStream zip = new ZipInputStream(stream);
ZipEntry entry;
do {
entry = zip.getNextEntry();
if( entry == null) {
zip.close();
return null;
}
} while( !entry.getName().equals(zipEntryName));
data.contentLength = entry.getSize();
data.lastModified = entry.getTime();
data.contentPath = contentPath;
InputStream s = zip;
if( data.contentLength == -1) {
Log.e("demo",new Object(){}.getClass().getEnclosingMethod().getName()+":: entry \""+entry+"\" has contentLength -1, so we will work around");
ByteArrayOutputStream buffer = new ByteArrayOutputStream();
int nRead;
// use buf to store data from the zip file entry in fixed size
byte[] buf = new byte[4096];
while ((nRead = zip.read(buf)) != -1) {
// dump that data into buffer, which is a growing buffer
buffer.write(buf, 0, nRead);
}
buffer.flush();
byte[] finalBuffer = buffer.toByteArray();
Log.e("demo",new Object(){}.getClass().getEnclosingMethod().getName()+":: entry \""+entry+"\" final data length: "+finalBuffer.length);
data.contentLength = finalBuffer.length;
s = new ByteArrayInputStream(finalBuffer);
}
final InputStream finalStream = s;
日志给了我们这个
getContentData:: entry "OEBPS/hayat-ghayr.html" has contentLength -1, so we will work around
getContentData:: entry "OEBPS/hayat-ghayr.html" final data length: 2378
getContentData:: entry "OEBPS/hayat-ghayr.html" has contentLength -1, so we will work around
getContentData:: entry "OEBPS/hayat-ghayr.html" final data length: 2378
有趣的是..如果我们在命令行中运行，那么该大小与该文件hayat-ghayr的实际内容长度完全匹配：
$ unzip -l b17c024e-89f1-42f7-a546-91d46610cedb.epub
Archive: b17c024e-89f1-42f7-a546-91d46610cedb.epub
Length Date Time Name
-------- ---- ---- ----
20 01-27-12 11:17 mimetype
2378 04-20-12 10:12 OEBPS/hayat-ghayr.html
6436 02-06-12 11:06 OEBPS/content.opf
112579 01-27-12 11:25 OEBPS/images/978-614-425-313-7-hayat-ghayr-cover.png
182575 01-27-12 11:25 OEBPS/images/978-614-425-313-7-hayat_fmt.png
7757 01-27-12 11:21 OEBPS/template.css
5643 01-27-12 11:18 OEBPS/hayat-ghayr-2.html
20144 01-27-12 11:17 OEBPS/hayat-ghayr-1.html
65543 01-27-12 11:17 OEBPS/hayat-ghayr-3.html
59434 01-27-12 11:17 OEBPS/hayat-ghayr-4.html
66768 01-27-12 11:17 OEBPS/hayat-ghayr-5.html
49117 01-27-12 11:17 OEBPS/hayat-ghayr-6.html
65346 01-27-12 11:17 OEBPS/hayat-ghayr-7.html
74196 01-27-12 11:17 OEBPS/hayat-ghayr-8.html
73998 01-27-12 11:17 OEBPS/hayat-ghayr-9.html
61031 01-27-12 11:17 OEBPS/hayat-ghayr-10.html
68297 01-27-12 11:17 OEBPS/hayat-ghayr-11.html
72084 01-27-12 11:17 OEBPS/hayat-ghayr-12.html
2386 01-27-12 11:17 OEBPS/hayat-ghayr-13.html
61132 01-27-12 11:17 OEBPS/hayat-ghayr-14.html
46320 01-27-12 11:17 OEBPS/hayat-ghayr-15.html
32673 01-27-12 11:17 OEBPS/hayat-ghayr-16.html
88584 01-27-12 11:17 OEBPS/hayat-ghayr-17.html
56474 01-27-12 11:17 OEBPS/hayat-ghayr-18.html
52840 01-27-12 11:17 OEBPS/hayat-ghayr-19.html
80022 01-27-12 11:17 OEBPS/hayat-ghayr-20.html
50781 01-27-12 11:17 OEBPS/hayat-ghayr-21.html
2765 01-27-12 11:17 OEBPS/hayat-ghayr-22.html
265 01-27-12 11:17 META-INF/container.xml
54942 01-27-12 11:17 OEBPS/images/277.png
5549 01-27-12 11:17 OEBPS/toc.ncx
1072 03-23-12 13:28 iTunesMetadata.plist
-------- -------
1529151 32 files