mykola/retracker
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

handle cases of malformed bencode data

Browse source
This commit is contained in:
mykola2312 2024-10-14 20:56:56 +03:00
parent d40e1cbe4e
commit 09f0e7dcee
3 changed files with 37 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

15
src/main/java/com/mykola2312/retracker/bencode/BTree.java
View file

@ -4,8 +4,8 @@ import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import com.mykola2312.retracker.bencode.error.BDecodeError;
import com.mykola2312.retracker.bencode.error.BDecodeMalformed;
import com.mykola2312.retracker.bencode.error.BDecodeParseError;
import com.mykola2312.retracker.bencode.error.BDecodeUnknown;
public class BTree {
private BValue root = null;
@ -40,22 +40,31 @@ public class BTree {
public BValue decode() throws BDecodeError {
BType type;
if (data.length < 2) {
/* no bencode data can be less than 2 bytes: for integer must be 'i0e' atleast,
* strings must be at least '0:' and lists and dicts can be empty
*/
throw new BDecodeMalformed(data, offset, "data is shorter than 2 bytes");
}
// consume and determine type
switch (data[offset]) {
case BE_INTEGER: type = BType.INTEGER; break;
case BE_LIST: type = BType.LIST; break;
case BE_DICT: type = BType.DICT; break;
default: throw new BDecodeUnknown(data, offset, data[offset]);
default: type = BType.STRING;
}
offset++;
if (type.equals(BType.INTEGER)) {
// advance until we hit end marker
int end = offset;
while (data[end] != BDecoder.BE_END) {
while (end < data.length && data[end] != BDecoder.BE_END) {
end++;
}
if (end == data.length) {
throw new BDecodeMalformed(data, offset, "no integer terminator");
}
// convert bytes to string and string to integer
byte[] bytes = Arrays.copyOfRange(data, offset, end);
return new BInteger(parseLong(bytes));

13
src/main/java/com/mykola2312/retracker/bencode/error/BDecodeMalformed.java Normal file
View file

@ -0,0 +1,13 @@
package com.mykola2312.retracker.bencode.error;
/* this exception should be thrown in cases buffer overrun,
* missing terminators and other nasty stuff. but it also
* could signal that there is parsing logic error
*/
public class BDecodeMalformed extends BDecodeError {
private static final long serialVersionUID = -8134440302174728903L;
public BDecodeMalformed(byte[] data, int offset, String reason) {
super(data, offset, reason);
}
}

12
src/test/java/com/mykola2312/retracker/bencode/BTreeTest.java
View file

@ -3,10 +3,12 @@ package com.mykola2312.retracker.bencode;
import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertThrows;
import org.junit.jupiter.api.Test;
import com.mykola2312.retracker.bencode.error.BDecodeError;
import com.mykola2312.retracker.bencode.error.BDecodeMalformed;
public class BTreeTest {
@Test
@ -24,4 +26,14 @@ public class BTreeTest {
System.out.println("testParseInt: " + root.toString());
});
}
@Test
public void testParseIntOverrun() throws BDecodeError {
final byte[] data = "i696969".getBytes();
BTree tree = new BTree();
assertThrows(BDecodeMalformed.class, () -> {
tree.decode(data);
});
}
}