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ReceivePack: report protocol parsing failures on channel 3 

If the client sent a well-formed enough request to see it wants to use
side-band-64k for status reporting (meaning its a modern client), but
any other command record was somehow invalid (e.g. corrupt SHA-1)
report the parsing exception using channel 3.  This allows clients to
see the failure and know the server will not be continuing.

git-core and JGit clients send all commands and then start a sideband
demux before sending the pack. By consuming all commands first we get
the client into a state where it can see and respond to the channel 3
server failure.

This behavior is useful on HTTPS connections when the client is buggy
and sent a corrupt command, but still managed to request side-band-64k
in the first line.

Change-Id: If385b91ceb9f024ccae2d1645caf15bc6b206130
This commit is contained in:
Shawn Pearce 2016-07-05 13:05:04 -07:00
parent a1bedf0822
commit 63cf87f863
3 changed files with 74 additions and 1 deletions
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40
org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/PushConnectionTest.java
View File

@ -43,13 +43,18 @@
package org.eclipse.jgit.transport;
import static org.eclipse.jgit.transport.BasePackPushConnection.CAPABILITY_REPORT_STATUS;
import static org.eclipse.jgit.transport.BasePackPushConnection.CAPABILITY_SIDE_BAND_64K;
import static org.eclipse.jgit.transport.RemoteRefUpdate.Status.REJECTED_OTHER_REASON;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.fail;
import java.io.IOException;
import java.io.StringWriter;
import java.util.HashMap;
import java.util.Map;
import org.eclipse.jgit.errors.TransportException;
import org.eclipse.jgit.internal.storage.dfs.DfsRepositoryDescription;
import org.eclipse.jgit.internal.storage.dfs.InMemoryRepository;
import org.eclipse.jgit.lib.Constants;
@ -133,4 +138,39 @@ public void testWrongOldIdDoesNotReplace() throws IOException {
assertEquals(REJECTED_OTHER_REASON, rru.getStatus());
assertEquals("invalid old id sent", rru.getMessage());
}
@Test
public void invalidCommand() throws IOException {
try (Transport tn = testProtocol.open(uri, client, "server");
InternalPushConnection c = (InternalPushConnection) tn.openPush()) {
StringWriter msgs = new StringWriter();
PacketLineOut pckOut = c.pckOut;
@SuppressWarnings("resource")
SideBandInputStream in = new SideBandInputStream(c.in,
NullProgressMonitor.INSTANCE, msgs, null);
// Explicitly invalid command, but sane enough capabilities.
StringBuilder buf = new StringBuilder();
buf.append("42");
buf.append(' ');
buf.append(obj2.name());
buf.append(' ');
buf.append("refs/heads/A" + obj2.name());
buf.append('\0').append(CAPABILITY_SIDE_BAND_64K);
buf.append(' ').append(CAPABILITY_REPORT_STATUS);
buf.append('\n');
pckOut.writeString(buf.toString());
pckOut.end();
try {
in.read();
fail("expected TransportException");
} catch (TransportException e) {
assertEquals(
"remote: error: invalid protocol: wanted 'old new ref'",
e.getMessage());
}
}
}
}

25
org.eclipse.jgit/src/org/eclipse/jgit/transport/BaseReceivePack.java
View File

@ -51,6 +51,7 @@
import static org.eclipse.jgit.transport.GitProtocolConstants.CAPABILITY_SIDE_BAND_64K;
import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_AGENT;
import static org.eclipse.jgit.transport.SideBandOutputStream.CH_DATA;
import static org.eclipse.jgit.transport.SideBandOutputStream.CH_ERROR;
import static org.eclipse.jgit.transport.SideBandOutputStream.CH_PROGRESS;
import static org.eclipse.jgit.transport.SideBandOutputStream.MAX_BUF;
@ -215,6 +216,7 @@ public Set<String> getCapabilities() {
/** Optional message output stream. */
protected OutputStream msgOut;
private SideBandOutputStream errOut;
/** Packet line input stream around {@link #rawIn}. */
protected PacketLineIn pckIn;
@ -879,6 +881,19 @@ public void sendError(final String what) {
}
}
private void fatalError(String msg) {
if (errOut != null) {
try {
errOut.write(Constants.encode(msg));
errOut.flush();
} catch (IOException e) {
// Ignore write failures
}
} else {
sendError(msg);
}
}
/**
* Send a message to the client, if it supports receiving them.
* <p>
@ -1128,7 +1143,14 @@ protected void recvCommands() throws IOException {
}
pushCert = certParser.build();
} catch (PackProtocolException e) {
sendError(e.getMessage());
if (sideBand) {
try {
pckIn.discardUntilEnd();
} catch (IOException e2) {
// Ignore read failures attempting to discard.
}
}
fatalError(e.getMessage());
throw e;
}
}
@ -1175,6 +1197,7 @@ protected void enableCapabilities() {
rawOut = new SideBandOutputStream(CH_DATA, MAX_BUF, out);
msgOut = new SideBandOutputStream(CH_PROGRESS, MAX_BUF, out);
errOut = new SideBandOutputStream(CH_ERROR, MAX_BUF, out);
pckOut = new PacketLineOut(rawOut);
pckOut.setFlushOnEnd(false);

10
org.eclipse.jgit/src/org/eclipse/jgit/transport/PacketLineIn.java
View File

@ -182,6 +182,16 @@ public String readStringRaw() throws IOException {
return RawParseUtils.decode(Constants.CHARSET, raw, 0, len);
}
void discardUntilEnd() throws IOException {
for (;;) {
int n = readLength();
if (n == 0) {
break;
}
IO.skipFully(in, n - 4);
}
}
int readLength() throws IOException {
IO.readFully(in, lineBuffer, 0, 4);
try {