forked from netty/netty
-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Pre-decompressed DNS record RData that may contain compression pointe…
…rs (netty#9311) Motivation: When decoding DnsRecord, if the record contains compression pointers, and not all compression pointers are decompressed, but part of the pointers are decompressed. Then when encoding the record, the compressed pointer will point to the wrong location, resulting in bad label problem. Modification: Pre-decompressed record RData that may contain compression pointers. Result: Fixes netty#8962
- Loading branch information
1 parent
deea51e
commit 18e4121
Showing
4 changed files
with
216 additions
and
89 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
132 changes: 132 additions & 0 deletions
132
codec-dns/src/main/java/io/netty/handler/codec/dns/DnsCodecUtil.java
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,132 @@ | ||
| /* | ||
| * Copyright 2019 The Netty Project | ||
| * | ||
| * The Netty Project licenses this file to you under the Apache License, | ||
| * version 2.0 (the "License"); you may not use this file except in compliance | ||
| * with the License. You may obtain a copy of the License at: | ||
| * | ||
| * http://www.apache.org/licenses/LICENSE-2.0 | ||
| * | ||
| * Unless required by applicable law or agreed to in writing, software | ||
| * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT | ||
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the | ||
| * License for the specific language governing permissions and limitations | ||
| * under the License. | ||
| */ | ||
|
|
||
| package io.netty.handler.codec.dns; | ||
|
|
||
| import io.netty.buffer.ByteBuf; | ||
| import io.netty.buffer.ByteBufUtil; | ||
| import io.netty.buffer.Unpooled; | ||
| import io.netty.handler.codec.CorruptedFrameException; | ||
| import io.netty.util.CharsetUtil; | ||
|
|
||
| import static io.netty.handler.codec.dns.DefaultDnsRecordDecoder.*; | ||
|
|
||
| final class DnsCodecUtil { | ||
| private DnsCodecUtil() { | ||
| // Util class | ||
| } | ||
|
|
||
| static void encodeDomainName(String name, ByteBuf buf) { | ||
| if (ROOT.equals(name)) { | ||
| // Root domain | ||
| buf.writeByte(0); | ||
| return; | ||
| } | ||
|
|
||
| final String[] labels = name.split("\\."); | ||
| for (String label : labels) { | ||
| final int labelLen = label.length(); | ||
| if (labelLen == 0) { | ||
| // zero-length label means the end of the name. | ||
| break; | ||
| } | ||
|
|
||
| buf.writeByte(labelLen); | ||
| ByteBufUtil.writeAscii(buf, label); | ||
| } | ||
|
|
||
| buf.writeByte(0); // marks end of name field | ||
| } | ||
|
|
||
| static String decodeDomainName(ByteBuf in) { | ||
| int position = -1; | ||
| int checked = 0; | ||
| final int end = in.writerIndex(); | ||
| final int readable = in.readableBytes(); | ||
|
|
||
| // Looking at the spec we should always have at least enough readable bytes to read a byte here but it seems | ||
| // some servers do not respect this for empty names. So just workaround this and return an empty name in this | ||
| // case. | ||
| // | ||
| // See: | ||
| // - https://github.com/netty/netty/issues/5014 | ||
| // - https://www.ietf.org/rfc/rfc1035.txt , Section 3.1 | ||
| if (readable == 0) { | ||
| return ROOT; | ||
| } | ||
|
|
||
| final StringBuilder name = new StringBuilder(readable << 1); | ||
| while (in.isReadable()) { | ||
| final int len = in.readUnsignedByte(); | ||
| final boolean pointer = (len & 0xc0) == 0xc0; | ||
| if (pointer) { | ||
| if (position == -1) { | ||
| position = in.readerIndex() + 1; | ||
| } | ||
|
|
||
| if (!in.isReadable()) { | ||
| throw new CorruptedFrameException("truncated pointer in a name"); | ||
| } | ||
|
|
||
| final int next = (len & 0x3f) << 8 | in.readUnsignedByte(); | ||
| if (next >= end) { | ||
| throw new CorruptedFrameException("name has an out-of-range pointer"); | ||
| } | ||
| in.readerIndex(next); | ||
|
|
||
| // check for loops | ||
| checked += 2; | ||
| if (checked >= end) { | ||
| throw new CorruptedFrameException("name contains a loop."); | ||
| } | ||
| } else if (len != 0) { | ||
| if (!in.isReadable(len)) { | ||
| throw new CorruptedFrameException("truncated label in a name"); | ||
| } | ||
| name.append(in.toString(in.readerIndex(), len, CharsetUtil.UTF_8)).append('.'); | ||
| in.skipBytes(len); | ||
| } else { // len == 0 | ||
| break; | ||
| } | ||
| } | ||
|
|
||
| if (position != -1) { | ||
| in.readerIndex(position); | ||
| } | ||
|
|
||
| if (name.length() == 0) { | ||
| return ROOT; | ||
| } | ||
|
|
||
| if (name.charAt(name.length() - 1) != '.') { | ||
| name.append('.'); | ||
| } | ||
|
|
||
| return name.toString(); | ||
| } | ||
|
|
||
| /** | ||
| * Decompress pointer data. | ||
| * @param compression comporession data | ||
| * @return decompressed data | ||
| */ | ||
| static ByteBuf decompressDomainName(ByteBuf compression) { | ||
| String domainName = decodeDomainName(compression); | ||
| ByteBuf result = compression.alloc().buffer(domainName.length() << 1); | ||
| encodeDomainName(domainName, result); | ||
| return result; | ||
| } | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters