GPG: implement more OpenPGP UserId matching formats

Instead of just looking for a substring match of user.signingKey
in a key's user ID implement the GPG matching formats[1] for:

'=' Full exact match
'<' Full exact match of the e-mail address
'@' Substring match within the e-mail address only
'*' General case-insensitive substring match (default)

When user.signingKey is not set, the committer's e-mail address is
used by default. In that case, use '<', i.e., require an exact match
on the OpenPGP e-mail address.

Also handle the optional "0x" prefix for (partial) key fingerprints.

[1] https://www.gnupg.org/documentation/manuals/gnupg/Specify-a-User-ID.html

Bug: 550335
Change-Id: I6ce482a099ff1a0dc9de45435cd4d3ec5b504f12
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

org.eclipse.jgit.test/META-INF/MANIFEST.MF

@@ -49,6 +49,7 @@ Import-Package: com.googlecode.javaewah;version="[1.1.6,2.0.0)",
  org.eclipse.jgit.junit.time;version="[5.6.0,5.7.0)",
  org.eclipse.jgit.lfs;version="[5.6.0,5.7.0)",
  org.eclipse.jgit.lib;version="[5.6.0,5.7.0)",
+ org.eclipse.jgit.lib.internal;version="[5.6.0,5.7.0)",
  org.eclipse.jgit.merge;version="[5.6.0,5.7.0)",
  org.eclipse.jgit.nls;version="[5.6.0,5.7.0)",
  org.eclipse.jgit.notes;version="[5.6.0,5.7.0)",

org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/internal/BouncyCastleGpgKeyLocatorTest.java

@@ -0,0 +1,167 @@
+/*
+ * Copyright (C) 2019, Thomas Wolf <thomas.wolf@paranor.ch>
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package org.eclipse.jgit.lib.internal;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.util.Locale;
+
+import org.junit.Test;
+
+public class BouncyCastleGpgKeyLocatorTest {
+
+	private static final String USER_ID = "Heinrich Heine <heinrichh@uni-duesseldorf.de>";
+
+	private static boolean match(String userId, String pattern) {
+		return BouncyCastleGpgKeyLocator.containsSigningKey(userId, pattern);
+	}
+
+	@Test
+	public void testFullMatch() throws Exception {
+		assertTrue(match(USER_ID,
+				"=Heinrich Heine <heinrichh@uni-duesseldorf.de>"));
+		assertFalse(match(USER_ID, "=Heinrich Heine"));
+		assertFalse(match(USER_ID, "= "));
+		assertFalse(match(USER_ID, "=heinrichh@uni-duesseldorf.de"));
+	}
+
+	@Test
+	public void testEmpty() throws Exception {
+		assertFalse(match(USER_ID, ""));
+		assertFalse(match(USER_ID, null));
+		assertFalse(match("", ""));
+		assertFalse(match(null, ""));
+		assertFalse(match(null, null));
+		assertFalse(match("", "something"));
+		assertFalse(match(null, "something"));
+	}
+
+	@Test
+	public void testFullEmail() throws Exception {
+		assertTrue(match(USER_ID, "<heinrichh@uni-duesseldorf.de>"));
+		assertTrue(match(USER_ID + " ", "<heinrichh@uni-duesseldorf.de>"));
+		assertFalse(match(USER_ID, "<>"));
+		assertFalse(match(USER_ID, "<h>"));
+		assertFalse(match(USER_ID, "<heinrichh>"));
+		assertFalse(match(USER_ID, "<uni-duesseldorf>"));
+		assertFalse(match(USER_ID, "<h@u>"));
+		assertFalse(match(USER_ID, "<HeinrichH@uni-duesseldorf.de>"));
+		assertFalse(match(USER_ID.substring(0, USER_ID.length() - 1),
+				"<heinrichh@uni-duesseldorf.de>"));
+		assertFalse(match("", "<>"));
+		assertFalse(match("", "<heinrichh@uni-duesseldorf.de>"));
+	}
+
+	@Test
+	public void testPartialEmail() throws Exception {
+		assertTrue(match(USER_ID, "@heinrichh@uni-duesseldorf.de"));
+		assertTrue(match(USER_ID, "@heinrichh"));
+		assertTrue(match(USER_ID, "@duesseldorf"));
+		assertTrue(match(USER_ID, "@uni-d"));
+		assertTrue(match(USER_ID, "@h"));
+		assertTrue(match(USER_ID, "@."));
+		assertTrue(match(USER_ID, "@h@u"));
+		assertFalse(match(USER_ID, "@ "));
+		assertFalse(match(USER_ID, "@"));
+		assertFalse(match(USER_ID, "@Heine"));
+		assertFalse(match(USER_ID, "@HeinrichH"));
+		assertFalse(match(USER_ID, "@Heinrich"));
+		assertFalse(match("", "@"));
+		assertFalse(match("", "@h"));
+	}
+
+	private void substringTests(String prefix) throws Exception {
+		assertTrue(match(USER_ID, prefix + "heinrichh@uni-duesseldorf.de"));
+		assertTrue(match(USER_ID, prefix + "heinrich"));
+		assertTrue(match(USER_ID, prefix + "HEIN"));
+		assertTrue(match(USER_ID, prefix + "Heine <"));
+		assertTrue(match(USER_ID, prefix + "UNI"));
+		assertTrue(match(USER_ID, prefix + "uni"));
+		assertTrue(match(USER_ID, prefix + "rich He"));
+		assertTrue(match(USER_ID, prefix + "h@u"));
+		assertTrue(match(USER_ID, prefix + USER_ID));
+		assertTrue(match(USER_ID, prefix + USER_ID.toUpperCase(Locale.ROOT)));
+		assertFalse(match(USER_ID, prefix + ""));
+		assertFalse(match(USER_ID, prefix + " "));
+		assertFalse(match(USER_ID, prefix + "yy"));
+		assertFalse(match("", prefix + ""));
+		assertFalse(match("", prefix + "uni"));
+	}
+
+	@Test
+	public void testSubstringPlain() throws Exception {
+		substringTests("");
+	}
+
+	@Test
+	public void testSubstringAsterisk() throws Exception {
+		substringTests("*");
+	}
+
+	@Test
+	public void testExplicitFingerprint() throws Exception {
+		assertFalse(match("John Fade <j.fade@example.com>", "0xfade"));
+		assertFalse(match("John Fade <0xfade@example.com>", "0xfade"));
+		assertFalse(match("", "0xfade"));
+	}
+
+	@Test
+	public void testImplicitFingerprint() throws Exception {
+		assertTrue(match("John Fade <j.fade@example.com>", "fade"));
+		assertTrue(match("John Fade <0xfade@example.com>", "fade"));
+		assertTrue(match("John Fade <j.fade@example.com>", "FADE"));
+		assertTrue(match("John Fade <0xfade@example.com>", "FADE"));
+	}
+
+	@Test
+	public void testZeroX() throws Exception {
+		assertTrue(match("John Fade <0xfade@example.com>", "0x"));
+		assertTrue(match("John Fade <0xfade@example.com>", "*0x"));
+		assertTrue(match("John Fade <0xfade@example.com>", "*0xfade"));
+		assertTrue(match("John Fade <0xfade@example.com>", "*0xFADE"));
+		assertTrue(match("John Fade <0xfade@example.com>", "@0xfade"));
+		assertFalse(match("John Fade <0xfade@example.com>", "@0xFADE"));
+		assertFalse(match("", "0x"));
+	}
+}

org.eclipse.jgit/META-INF/MANIFEST.MF

@@ -99,7 +99,7 @@ Export-Package: org.eclipse.jgit.annotations;version="5.6.0",
    org.eclipse.jgit.treewalk,
    org.eclipse.jgit.transport,
    org.eclipse.jgit.submodule",
- org.eclipse.jgit.lib.internal;version="5.6.0";x-internal:=true,
+ org.eclipse.jgit.lib.internal;version="5.6.0";x-friends:="org.eclipse.jgit.test",
  org.eclipse.jgit.merge;version="5.6.0";
   uses:="org.eclipse.jgit.lib,
    org.eclipse.jgit.treewalk,

org.eclipse.jgit/src/org/eclipse/jgit/lib/internal/BouncyCastleGpgKeyLocator.java

@@ -92,6 +92,7 @@ import org.eclipse.jgit.api.errors.CanceledException;
 import org.eclipse.jgit.errors.UnsupportedCredentialItem;
 import org.eclipse.jgit.internal.JGitText;
 import org.eclipse.jgit.util.FS;
+import org.eclipse.jgit.util.StringUtils;
 import org.eclipse.jgit.util.SystemReader;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -192,14 +193,87 @@ class BouncyCastleGpgKeyLocator {
 		}
 	}
 
-	private boolean containsSigningKey(String userId) {
-		return userId.toLowerCase(Locale.ROOT)
-				.contains(signingKey.toLowerCase(Locale.ROOT));
+	/**
+	 * Checks whether a given OpenPGP {@code userId} matches a given
+	 * {@code signingKeySpec}, which is supposed to have one of the formats
+	 * defined by GPG.
+	 * <p>
+	 * Not all formats are supported; only formats starting with '=', '&lt;',
+	 * '@', and '*' are handled. Any other format results in a case-insensitive
+	 * substring match.
+	 * </p>
+	 *
+	 * @param userId
+	 *            of a key
+	 * @param signingKeySpec
+	 *            GPG key identification
+	 * @return whether the {@code userId} matches
+	 * @see <a href=
+	 *      "https://www.gnupg.org/documentation/manuals/gnupg/Specify-a-User-ID.html">GPG
+	 *      Documentation: How to Specify a User ID</a>
+	 */
+	static boolean containsSigningKey(String userId, String signingKeySpec) {
+		if (StringUtils.isEmptyOrNull(userId)
+				|| StringUtils.isEmptyOrNull(signingKeySpec)) {
+			return false;
+		}
+		String toMatch = signingKeySpec;
+		if (toMatch.startsWith("0x") && toMatch.trim().length() > 2) { //$NON-NLS-1$
+			return false; // Explicit fingerprint
+		}
+		int command = toMatch.charAt(0);
+		switch (command) {
+		case '=':
+		case '<':
+		case '@':
+		case '*':
+			toMatch = toMatch.substring(1);
+			if (toMatch.isEmpty()) {
+				return false;
+			}
+			break;
+		default:
+			break;
+		}
+		switch (command) {
+		case '=':
+			return userId.equals(toMatch);
+		case '<': {
+			int begin = userId.indexOf('<');
+			int end = userId.indexOf('>', begin + 1);
+			int stop = toMatch.indexOf('>');
+			return begin >= 0 && end > begin + 1 && stop > 0
+					&& userId.substring(begin + 1, end)
+							.equals(toMatch.substring(0, stop));
+		}
+		case '@': {
+			int begin = userId.indexOf('<');
+			int end = userId.indexOf('>', begin + 1);
+			return begin >= 0 && end > begin + 1
+					&& userId.substring(begin + 1, end).contains(toMatch);
+		}
+		default:
+			if (toMatch.trim().isEmpty()) {
+				return false;
+			}
+			return userId.toLowerCase(Locale.ROOT)
+					.contains(toMatch.toLowerCase(Locale.ROOT));
+		}
+	}
+
+	private String toFingerprint(String keyId) {
+		if (keyId.startsWith("0x")) { //$NON-NLS-1$
+			return keyId.substring(2);
+		}
+		return keyId;
 	}
 
 	private PGPPublicKey findPublicKeyByKeyId(KeyBlob keyBlob)
 			throws IOException {
-		String keyId = signingKey.toLowerCase(Locale.ROOT);
+		String keyId = toFingerprint(signingKey).toLowerCase(Locale.ROOT);
+		if (keyId.isEmpty()) {
+			return null;
+		}
 		for (KeyInformation keyInfo : keyBlob.getKeyInformation()) {
 			String fingerprint = Hex.toHexString(keyInfo.getFingerprint())
 					.toLowerCase(Locale.ROOT);
@@ -213,7 +287,7 @@ class BouncyCastleGpgKeyLocator {
 	private PGPPublicKey findPublicKeyByUserId(KeyBlob keyBlob)
 			throws IOException {
 		for (UserID userID : keyBlob.getUserIds()) {
-			if (containsSigningKey(userID.getUserIDAsString())) {
+			if (containsSigningKey(userID.getUserIDAsString(), signingKey)) {
 				return getSigningPublicKey(keyBlob);
 			}
 		}
@@ -446,7 +520,7 @@ class BouncyCastleGpgKeyLocator {
 					PGPUtil.getDecoderStream(new BufferedInputStream(in)),
 					new JcaKeyFingerprintCalculator());
 
-			String keyId = signingkey.toLowerCase(Locale.ROOT);
+			String keyId = toFingerprint(signingkey).toLowerCase(Locale.ROOT);
 			Iterator<PGPSecretKeyRing> keyrings = pgpSec.getKeyRings();
 			while (keyrings.hasNext()) {
 				PGPSecretKeyRing keyRing = keyrings.next();
@@ -464,7 +538,7 @@ class BouncyCastleGpgKeyLocator {
 					Iterator<String> userIDs = key.getUserIDs();
 					while (userIDs.hasNext()) {
 						String userId = userIDs.next();
-						if (containsSigningKey(userId)) {
+						if (containsSigningKey(userId, signingKey)) {
 							return key;
 						}
 					}
@@ -492,7 +566,7 @@ class BouncyCastleGpgKeyLocator {
 					new BufferedInputStream(in),
 					new JcaKeyFingerprintCalculator());
 
-			String keyId = signingKey.toLowerCase(Locale.ROOT);
+			String keyId = toFingerprint(signingKey).toLowerCase(Locale.ROOT);
 			Iterator<PGPPublicKeyRing> keyrings = pgpPub.getKeyRings();
 			while (keyrings.hasNext()) {
 				PGPPublicKeyRing keyRing = keyrings.next();
@@ -509,7 +583,7 @@ class BouncyCastleGpgKeyLocator {
 					Iterator<String> userIDs = key.getUserIDs();
 					while (userIDs.hasNext()) {
 						String userId = userIDs.next();
-						if (containsSigningKey(userId)) {
+						if (containsSigningKey(userId, signingKey)) {
 							return key;
 						}
 					}

org.eclipse.jgit/src/org/eclipse/jgit/lib/internal/BouncyCastleGpgSigner.java

@@ -115,7 +115,7 @@ public class BouncyCastleGpgSigner extends GpgSigner {
 			NoSuchAlgorithmException, NoSuchProviderException, PGPException,
 			URISyntaxException {
 		if (gpgSigningKey == null || gpgSigningKey.isEmpty()) {
-			gpgSigningKey = committer.getEmailAddress();
+			gpgSigningKey = '<' + committer.getEmailAddress() + '>';
 		}
 
 		BouncyCastleGpgKeyLocator keyHelper = new BouncyCastleGpgKeyLocator(