PushCertificateParser.java
/*
* Copyright (C) 2015, Google Inc. and others
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0 which is available at
* https://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package org.eclipse.jgit.transport;
import static org.eclipse.jgit.transport.ReceivePack.parseCommand;
import static org.eclipse.jgit.transport.GitProtocolConstants.CAPABILITY_PUSH_CERT;
import java.io.EOFException;
import java.io.IOException;
import java.io.Reader;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.TimeUnit;
import org.eclipse.jgit.errors.PackProtocolException;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.transport.PushCertificate.NonceStatus;
import org.eclipse.jgit.util.IO;
/**
* Parser for signed push certificates.
*
* @since 4.0
*/
public class PushCertificateParser {
static final String BEGIN_SIGNATURE =
"-----BEGIN PGP SIGNATURE-----"; //$NON-NLS-1$
static final String END_SIGNATURE =
"-----END PGP SIGNATURE-----"; //$NON-NLS-1$
static final String VERSION = "certificate version"; //$NON-NLS-1$
static final String PUSHER = "pusher"; //$NON-NLS-1$
static final String PUSHEE = "pushee"; //$NON-NLS-1$
static final String NONCE = "nonce"; //$NON-NLS-1$
static final String END_CERT = "push-cert-end"; //$NON-NLS-1$
private static final String VERSION_0_1 = "0.1"; //$NON-NLS-1$
private static interface StringReader {
/**
* @return the next string from the input, up to an optional newline, with
* newline stripped if present
*
* @throws EOFException
* if EOF was reached.
* @throws IOException
* if an error occurred during reading.
*/
String read() throws EOFException, IOException;
}
private static class PacketLineReader implements StringReader {
private final PacketLineIn pckIn;
private PacketLineReader(PacketLineIn pckIn) {
this.pckIn = pckIn;
}
@Override
public String read() throws IOException {
return pckIn.readString();
}
}
private static class StreamReader implements StringReader {
private final Reader reader;
private StreamReader(Reader reader) {
this.reader = reader;
}
@Override
public String read() throws IOException {
// Presize for a command containing 2 SHA-1s and some refname.
String line = IO.readLine(reader, 41 * 2 + 64);
if (line.isEmpty()) {
throw new EOFException();
} else if (line.charAt(line.length() - 1) == '\n') {
line = line.substring(0, line.length() - 1);
}
return line;
}
}
/**
* Parse a push certificate from a reader.
* <p>
* Differences from the {@link org.eclipse.jgit.transport.PacketLineIn}
* receiver methods:
* <ul>
* <li>Does not use pkt-line framing.</li>
* <li>Reads an entire cert in one call rather than depending on a loop in
* the caller.</li>
* <li>Does not assume a {@code "push-cert-end"} line.</li>
* </ul>
*
* @param r
* input reader; consumed only up until the end of the next
* signature in the input.
* @return the parsed certificate, or null if the reader was at EOF.
* @throws org.eclipse.jgit.errors.PackProtocolException
* if the certificate is malformed.
* @throws java.io.IOException
* if there was an error reading from the input.
* @since 4.1
*/
public static PushCertificate fromReader(Reader r)
throws PackProtocolException, IOException {
return new PushCertificateParser().parse(r);
}
/**
* Parse a push certificate from a string.
*
* @see #fromReader(Reader)
* @param str
* input string.
* @return the parsed certificate.
* @throws org.eclipse.jgit.errors.PackProtocolException
* if the certificate is malformed.
* @throws java.io.IOException
* if there was an error reading from the input.
* @since 4.1
*/
public static PushCertificate fromString(String str)
throws PackProtocolException, IOException {
return fromReader(new java.io.StringReader(str));
}
private boolean received;
private String version;
private PushCertificateIdent pusher;
private String pushee;
/** The nonce that was sent to the client. */
private String sentNonce;
/**
* The nonce the pusher signed.
* <p>
* This may vary from {@link #sentNonce}; see git-core documentation for
* reasons.
*/
private String receivedNonce;
private NonceStatus nonceStatus;
private String signature;
/** Database we write the push certificate into. */
private final Repository db;
/**
* The maximum time difference which is acceptable between advertised nonce
* and received signed nonce.
*/
private final int nonceSlopLimit;
private final boolean enabled;
private final NonceGenerator nonceGenerator;
private final List<ReceiveCommand> commands = new ArrayList<>();
/**
* <p>Constructor for PushCertificateParser.</p>
*
* @param into
* destination repository for the push.
* @param cfg
* configuration for signed push.
* @since 4.1
*/
public PushCertificateParser(Repository into, SignedPushConfig cfg) {
if (cfg != null) {
nonceSlopLimit = cfg.getCertNonceSlopLimit();
nonceGenerator = cfg.getNonceGenerator();
} else {
nonceSlopLimit = 0;
nonceGenerator = null;
}
db = into;
enabled = nonceGenerator != null;
}
private PushCertificateParser() {
db = null;
nonceSlopLimit = 0;
nonceGenerator = null;
enabled = true;
}
/**
* Parse a push certificate from a reader.
*
* @see #fromReader(Reader)
* @param r
* input reader; consumed only up until the end of the next
* signature in the input.
* @return the parsed certificate, or null if the reader was at EOF.
* @throws org.eclipse.jgit.errors.PackProtocolException
* if the certificate is malformed.
* @throws java.io.IOException
* if there was an error reading from the input.
* @since 4.1
*/
public PushCertificate parse(Reader r)
throws PackProtocolException, IOException {
StreamReader reader = new StreamReader(r);
receiveHeader(reader, true);
String line;
try {
while (!(line = reader.read()).isEmpty()) {
if (line.equals(BEGIN_SIGNATURE)) {
receiveSignature(reader);
break;
}
addCommand(line);
}
} catch (EOFException e) {
// EOF reached, but might have been at a valid state. Let build call below
// sort it out.
}
return build();
}
/**
* Build the parsed certificate
*
* @return the parsed certificate, or null if push certificates are
* disabled.
* @throws java.io.IOException
* if the push certificate has missing or invalid fields.
* @since 4.1
*/
public PushCertificate build() throws IOException {
if (!received || !enabled) {
return null;
}
try {
return new PushCertificate(version, pusher, pushee, receivedNonce,
nonceStatus, Collections.unmodifiableList(commands), signature);
} catch (IllegalArgumentException e) {
throw new IOException(e.getMessage(), e);
}
}
/**
* Whether the repository is configured to use signed pushes in this
* context.
*
* @return if the repository is configured to use signed pushes in this
* context.
* @since 4.0
*/
public boolean enabled() {
return enabled;
}
/**
* Get the whole string for the nonce to be included into the capability
* advertisement
*
* @return the whole string for the nonce to be included into the capability
* advertisement, or null if push certificates are disabled.
* @since 4.0
*/
public String getAdvertiseNonce() {
String nonce = sentNonce();
if (nonce == null) {
return null;
}
return CAPABILITY_PUSH_CERT + '=' + nonce;
}
private String sentNonce() {
if (sentNonce == null && nonceGenerator != null) {
sentNonce = nonceGenerator.createNonce(db,
TimeUnit.MILLISECONDS.toSeconds(System.currentTimeMillis()));
}
return sentNonce;
}
private static String parseHeader(StringReader reader, String header)
throws IOException {
return parseHeader(reader.read(), header);
}
private static String parseHeader(String s, String header)
throws IOException {
if (s.isEmpty()) {
throw new EOFException();
}
if (s.length() <= header.length()
|| !s.startsWith(header)
|| s.charAt(header.length()) != ' ') {
throw new PackProtocolException(MessageFormat.format(
JGitText.get().pushCertificateInvalidField, header));
}
return s.substring(header.length() + 1);
}
/**
* Receive a list of commands from the input encapsulated in a push
* certificate.
* <p>
* This method doesn't parse the first line {@code "push-cert \NUL
* <capabilities>"}, but assumes the first line including the
* capabilities has already been handled by the caller.
*
* @param pckIn
* where we take the push certificate header from.
* @param stateless
* affects nonce verification. When {@code stateless = true} the
* {@code NonceGenerator} will allow for some time skew caused by
* clients disconnected and reconnecting in the stateless smart
* HTTP protocol.
* @throws java.io.IOException
* if the certificate from the client is badly malformed or the
* client disconnects before sending the entire certificate.
* @since 4.0
*/
public void receiveHeader(PacketLineIn pckIn, boolean stateless)
throws IOException {
receiveHeader(new PacketLineReader(pckIn), stateless);
}
private void receiveHeader(StringReader reader, boolean stateless)
throws IOException {
try {
try {
version = parseHeader(reader, VERSION);
} catch (EOFException e) {
return;
}
received = true;
if (!version.equals(VERSION_0_1)) {
throw new PackProtocolException(MessageFormat.format(
JGitText.get().pushCertificateInvalidFieldValue, VERSION, version));
}
String rawPusher = parseHeader(reader, PUSHER);
pusher = PushCertificateIdent.parse(rawPusher);
if (pusher == null) {
throw new PackProtocolException(MessageFormat.format(
JGitText.get().pushCertificateInvalidFieldValue,
PUSHER, rawPusher));
}
String next = reader.read();
if (next.startsWith(PUSHEE)) {
pushee = parseHeader(next, PUSHEE);
receivedNonce = parseHeader(reader, NONCE);
} else {
receivedNonce = parseHeader(next, NONCE);
}
nonceStatus = nonceGenerator != null
? nonceGenerator.verify(
receivedNonce, sentNonce(), db, stateless, nonceSlopLimit)
: NonceStatus.UNSOLICITED;
// An empty line.
if (!reader.read().isEmpty()) {
throw new PackProtocolException(
JGitText.get().pushCertificateInvalidHeader);
}
} catch (EOFException eof) {
throw new PackProtocolException(
JGitText.get().pushCertificateInvalidHeader, eof);
}
}
/**
* Read the PGP signature.
* <p>
* This method assumes the line
* {@code "-----BEGIN PGP SIGNATURE-----"} has already been parsed,
* and continues parsing until an {@code "-----END PGP SIGNATURE-----"} is
* found, followed by {@code "push-cert-end"}.
*
* @param pckIn
* where we read the signature from.
* @throws java.io.IOException
* if the signature is invalid.
* @since 4.0
*/
public void receiveSignature(PacketLineIn pckIn) throws IOException {
StringReader reader = new PacketLineReader(pckIn);
receiveSignature(reader);
if (!reader.read().equals(END_CERT)) {
throw new PackProtocolException(
JGitText.get().pushCertificateInvalidSignature);
}
}
private void receiveSignature(StringReader reader) throws IOException {
received = true;
try {
StringBuilder sig = new StringBuilder(BEGIN_SIGNATURE).append('\n');
String line;
while (!(line = reader.read()).equals(END_SIGNATURE)) {
sig.append(line).append('\n');
}
signature = sig.append(END_SIGNATURE).append('\n').toString();
} catch (EOFException eof) {
throw new PackProtocolException(
JGitText.get().pushCertificateInvalidSignature, eof);
}
}
/**
* Add a command to the signature.
*
* @param cmd
* the command.
* @since 4.1
*/
public void addCommand(ReceiveCommand cmd) {
commands.add(cmd);
}
/**
* Add a command to the signature.
*
* @param line
* the line read from the wire that produced this
* command, with optional trailing newline already trimmed.
* @throws org.eclipse.jgit.errors.PackProtocolException
* if the raw line cannot be parsed to a command.
* @since 4.0
*/
public void addCommand(String line) throws PackProtocolException {
commands.add(parseCommand(line));
}
}