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bodewig pushed a commit to branch master
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The following commit(s) were added to refs/heads/master by this push:
new e04fbe7ff try to properly decode multibyte encoded names in tar entries
e04fbe7ff is described below
commit e04fbe7ffa4f549bdc00bdfce688fb587120eedd
Author: Stefan Bodewig <stefan.bode...@innoq.com>
AuthorDate: Sat Nov 26 18:47:07 2022 +0100
try to properly decode multibyte encoded names in tar entries
---
src/main/org/apache/tools/tar/TarUtils.java | 71 +++++++++++++++++++++++++++--
1 file changed, 66 insertions(+), 5 deletions(-)
diff --git a/src/main/org/apache/tools/tar/TarUtils.java
b/src/main/org/apache/tools/tar/TarUtils.java
index f6f103654..ffa24b1cb 100644
--- a/src/main/org/apache/tools/tar/TarUtils.java
+++ b/src/main/org/apache/tools/tar/TarUtils.java
@@ -26,6 +26,8 @@ package org.apache.tools.tar;
import java.io.IOException;
import java.math.BigInteger;
import java.nio.ByteBuffer;
+import java.util.Arrays;
+import java.util.WeakHashMap;
import org.apache.tools.zip.ZipEncoding;
import org.apache.tools.zip.ZipEncodingHelper;
@@ -38,6 +40,10 @@ import org.apache.tools.zip.ZipEncodingHelper;
public class TarUtils {
private static final int BYTE_MASK = 255;
+ private static final String NUL = "\0";
+ private static final String X = "X";
+ private static final String X_NUL = "X\0";
+ private static final WeakHashMap<ZipEncoding, byte[]> NUL_BY_ENCODING =
new WeakHashMap<>();
static final ZipEncoding DEFAULT_ENCODING =
ZipEncodingHelper.getZipEncoding(null);
@@ -286,20 +292,75 @@ public class TarUtils {
final ZipEncoding encoding)
throws IOException {
+ final byte[] nul = getNulByteEquivalent(encoding);
+ final int nulLen = nul.length;
int len = 0;
- for (; len < length; ++len) {
- if (buffer[offset + len] == 0) {
- break;
+ if (nulLen == 1) {
+ final byte nulByte = nul[0];
+ for (; len < length; ++len) {
+ if (buffer[offset + len] == nulByte) {
+ break;
+ }
+ }
+ } else if (nulLen == 0) {
+ len = length;
+ } else {
+ boolean found = false;
+ for (; len <= length - nulLen; ++len) {
+ // six-arg Arrays.equals requires Java 9
+ byte[] atOffset = Arrays.copyOfRange(buffer, offset + len,
offset + len + nulLen);
+ if (Arrays.equals(atOffset, nul)) {
+ found = true;
+ break;
+ }
+ }
+ if (!found) {
+ len = length;
}
}
if (len > 0) {
- final byte[] b = new byte[len];
- System.arraycopy(buffer, offset, b, 0, len);
+ final byte[] b = Arrays.copyOfRange(buffer, offset, offset + len);
return encoding.decode(b);
}
return "";
}
+ private static byte[] getNulByteEquivalent(ZipEncoding encoding) throws
IOException {
+ byte[] value = NUL_BY_ENCODING.get(encoding);
+ if (value == null) {
+ value = getUncachedNulByteEquivalent(encoding);
+ NUL_BY_ENCODING.put(encoding, value);
+ }
+ return value;
+ }
+
+ private static byte[] getUncachedNulByteEquivalent(ZipEncoding encoding)
throws IOException {
+ final ByteBuffer nulBuffer = encoding.encode(NUL);
+ final int nulLen = nulBuffer.limit() - nulBuffer.position();
+ final byte[] nul =
+ Arrays.copyOfRange(nulBuffer.array(), nulBuffer.arrayOffset(),
nulBuffer.arrayOffset() + nulLen);
+ if (nulLen <= 1) {
+ return nul;
+ }
+ final ByteBuffer xBuffer = encoding.encode(X);
+ final int xBufferLen = xBuffer.limit() - xBuffer.position();
+ final ByteBuffer xNulBuffer = encoding.encode(X_NUL);
+ final int xNulBufferLen = xNulBuffer.limit() - xNulBuffer.position();
+ if (xBufferLen >= xNulBufferLen) {
+ return nul;
+ }
+ final byte[] x =
+ Arrays.copyOfRange(xBuffer.array(), xBuffer.arrayOffset(),
xBuffer.arrayOffset() + xBufferLen);
+ final byte[] nulPrefix =
+ Arrays.copyOfRange(xNulBuffer.array(), xNulBuffer.arrayOffset(),
xNulBuffer.arrayOffset() + xBufferLen);
+ if (Arrays.equals(x, nulPrefix)) {
+ // strip of BOM or similar prefix
+ return Arrays.copyOfRange(xNulBuffer.array(),
xNulBuffer.arrayOffset() + xBufferLen,
+ xNulBuffer.arrayOffset() +
xNulBufferLen);
+ }
+ return nul;
+ }
+
/**
* Copy a name into a buffer.
* Copies characters from the name into the buffer
