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[UNDERTOW-2451] fix the information leakage issues #1668

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[UNDERTOW-2451] fix the information leakage issues #1668

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560b84c
fix CVE-2024-7885 vul#2
BFionaccept Sep 25, 2024
9b5acb4
fix the message leak issue in HPACK decoder
BFionaccept Sep 25, 2024
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13 changes: 1 addition & 12 deletions core/src/main/java/io/undertow/protocols/ajp/AjpResponseParser.java
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Original file line number Diff line number Diff line change
Expand Up @@ -224,11 +224,6 @@ public int getReadBodyChunkSize() {
*/
public int stringLength = -1;

/**
* The current string being read
*/
public StringBuilder currentString;

/**
* when reading the first byte of an integer this stores the first value. It is set to -1 to signify that
* the first byte has not been read yet.
Expand All @@ -248,7 +243,6 @@ public void reset() {
reasonPhrase = null;
headers = new HeaderMap();
stringLength = -1;
currentString = null;
currentIntegerPart = -1;
readHeaders = 0;
}
Expand Down Expand Up @@ -300,12 +294,8 @@ protected StringHolder parseString(ByteBuffer buf, boolean header) {
this.stringLength = -1;
return new StringHolder(null, true, false);
}
StringBuilder builder = this.currentString;
final StringBuilder builder = new StringBuilder();

if (builder == null) {
builder = new StringBuilder();
this.currentString = builder;
}
int length = builder.length();
while (length < stringLength) {
if (!buf.hasRemaining()) {
Expand All @@ -323,7 +313,6 @@ protected StringHolder parseString(ByteBuffer buf, boolean header) {

if (buf.hasRemaining()) {
buf.get(); //null terminator
this.currentString = null;
this.stringLength = -1;
this.containsUrlCharacters = false;
return new StringHolder(builder.toString(), true, containsUrlCharacters);
Expand Down
6 changes: 2 additions & 4 deletions core/src/main/java/io/undertow/protocols/http2/HpackDecoder.java
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Original file line number Diff line number Diff line change
Expand Up @@ -73,8 +73,6 @@ public class HpackDecoder {

private boolean first = true;

private final StringBuilder stringBuilder = new StringBuilder();

public HpackDecoder(int maxAllowedMemorySize) {
this.specifiedMemorySize = Math.min(Hpack.DEFAULT_TABLE_SIZE, maxAllowedMemorySize);
this.maxAllowedMemorySize = maxAllowedMemorySize;
Expand Down Expand Up @@ -247,11 +245,11 @@ private String readHpackString(ByteBuffer buffer) throws HpackException {
if (huffman) {
return readHuffmanString(length, buffer);
}
StringBuilder stringBuilder = new StringBuilder(length);
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for (int i = 0; i < length; ++i) {
stringBuilder.append((char) (buffer.get() & 0xFF));
}
String ret = stringBuilder.toString();
stringBuilder.setLength(0);
if (ret.isEmpty()) {
//return the interned empty string, rather than allocating a new one each time
return "";
Expand All @@ -260,12 +258,12 @@ private String readHpackString(ByteBuffer buffer) throws HpackException {
}

private String readHuffmanString(int length, ByteBuffer buffer) throws HpackException {
StringBuilder stringBuilder = new StringBuilder(length);
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final ?

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In this fix, I referenced the patch for a similar vulnerability (CVE-2020-17527) in the corresponding functional module of Tomcat, as shown in this commit: apache/tomcat@d56293f#diff-98723542790b05d2e3c2dadeef7c632e641e3118b3b809660e9b1ef41686cfe0R226. I removed the final from the StringBuilder stringBuilder declaration, enhancing code flexibility and allowing for future reassignment if needed.

Certainly, I think it is also acceptable to retain the final modifier.

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Oh, I’m sorry, I accidentally deleted a previous conversation.

HPackHuffman.decode(buffer, length, stringBuilder);
String ret = stringBuilder.toString();
if (ret.isEmpty()) {
return "";
}
stringBuilder.setLength(0);
return ret;
}

Expand Down
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