SubmoduleAddCommand: Reject submodule URIs that look like cli options

In C git versions before 2.19.1, the submodule is fetched by running
"git clone <uri> <path>". A URI starting with "-" would be interpreted
as an option, causing security problems. See CVE-2018-17456.

Refuse to add submodules with URIs, names or paths starting with "-",
that could be confused with command line arguments.

[jn: backported to JGit 4.7.y, bringing portions of Masaya Suzuki's
 dotdot check code in v5.1.0.201808281540-m3~57 (Add API to specify
 the submodule name, 2018-07-12) along for the ride]

Change-Id: I2607c3acc480b75ab2b13386fe2cac435839f017
Signed-off-by: Ivan Frade <ifrade@google.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

5 files changed, 160 insertions, 2 deletions

diff --git a/org.eclipse.jgit/.settings/.api_filters b/org.eclipse.jgit/.settings/.api_filters
index 4badd2c1c4..ed43015a39 100644
--- a/org.eclipse.jgit/.settings/.api_filters
+++ b/org.eclipse.jgit/.settings/.api_filters
@@ -3,7 +3,7 @@
     <resource path="META-INF/MANIFEST.MF">
         <filter id="924844039">
             <message_arguments>
-                <message_argument value="4.7.4"/>
+                <message_argument value="4.7.5"/>
                 <message_argument value="4.7.0"/>
             </message_arguments>
         </filter>
diff --git a/org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties b/org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties
index 34457c9367..2083e1eef9 100644
--- a/org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties
+++ b/org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties
@@ -358,6 +358,7 @@ invalidKey=Invalid key: {0}
 invalidLineInConfigFile=Invalid line in config file
 invalidModeFor=Invalid mode {0} for {1} {2} in {3}.
 invalidModeForPath=Invalid mode {0} for path {1}
+invalidNameContainsDotDot=Invalid name (contains ".."): {0}
 invalidObject=Invalid {0} {1}: {2}
 invalidOldIdSent=invalid old id sent
 invalidPacketLineHeader=Invalid packet line header: {0}
@@ -605,7 +606,10 @@ storePushCertMultipleRefs=Store push certificate for {0} refs
 storePushCertOneRef=Store push certificate for {0}
 storePushCertReflog=Store push certificate
 submoduleExists=Submodule ''{0}'' already exists in the index
+submoduleNameInvalid=Invalid submodule name ''{0}''
 submoduleParentRemoteUrlInvalid=Cannot remove segment from remote url ''{0}''
+submodulePathInvalid=Invalid submodule path ''{0}''
+submoduleUrlInvalid=Invalid submodule URL ''{0}''
 submodulesNotSupported=Submodules are not supported
 supportOnlyPackIndexVersion2=Only support index version 2
 symlinkCannotBeWrittenAsTheLinkTarget=Symlink "{0}" cannot be written as the link target cannot be read from within Java.
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/api/SubmoduleAddCommand.java b/org.eclipse.jgit/src/org/eclipse/jgit/api/SubmoduleAddCommand.java
index 0519d454ea..e3ba8945df 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/api/SubmoduleAddCommand.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/api/SubmoduleAddCommand.java
@@ -51,6 +51,7 @@ import org.eclipse.jgit.api.errors.JGitInternalException;
 import org.eclipse.jgit.api.errors.NoFilepatternException;
 import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.eclipse.jgit.internal.JGitText;
+import org.eclipse.jgit.internal.submodule.SubmoduleValidator;
 import org.eclipse.jgit.lib.ConfigConstants;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.NullProgressMonitor;
@@ -158,6 +159,14 @@ public class SubmoduleAddCommand extends
 			throw new IllegalArgumentException(JGitText.get().uriNotConfigured);
 
 		try {
+			SubmoduleValidator.assertValidSubmoduleName(path);
+			SubmoduleValidator.assertValidSubmodulePath(path);
+			SubmoduleValidator.assertValidSubmoduleUri(uri);
+		} catch (SubmoduleValidator.SubmoduleValidationException e) {
+			throw new IllegalArgumentException(e.getMessage());
+		}
+
+		try {
 			if (submoduleExists())
 				throw new JGitInternalException(MessageFormat.format(
 						JGitText.get().submoduleExists, path));
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/JGitText.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/JGitText.java
index 41f3c2a488..8586763970 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/JGitText.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/JGitText.java
@@ -417,6 +417,7 @@ public class JGitText extends TranslationBundle {
 	/***/ public String invalidLineInConfigFile;
 	/***/ public String invalidModeFor;
 	/***/ public String invalidModeForPath;
+	/***/ public String invalidNameContainsDotDot;
 	/***/ public String invalidObject;
 	/***/ public String invalidOldIdSent;
 	/***/ public String invalidPacketLineHeader;
@@ -664,8 +665,11 @@ public class JGitText extends TranslationBundle {
 	/***/ public String storePushCertOneRef;
 	/***/ public String storePushCertReflog;
 	/***/ public String submoduleExists;
-	/***/ public String submodulesNotSupported;
+	/***/ public String submoduleNameInvalid;
 	/***/ public String submoduleParentRemoteUrlInvalid;
+	/***/ public String submodulePathInvalid;
+	/***/ public String submodulesNotSupported;
+	/***/ public String submoduleUrlInvalid;
 	/***/ public String supportOnlyPackIndexVersion2;
 	/***/ public String symlinkCannotBeWrittenAsTheLinkTarget;
 	/***/ public String systemConfigFileInvalid;
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/submodule/SubmoduleValidator.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/submodule/SubmoduleValidator.java
new file mode 100644
index 0000000000..4821c80f00
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/submodule/SubmoduleValidator.java
@@ -0,0 +1,141 @@
+/*
+ * Copyright (C) 2018, Google LLC.
+ * 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.internal.submodule;
+
+import java.text.MessageFormat;
+
+import org.eclipse.jgit.internal.JGitText;
+
+/**
+ * Validations for the git submodule fields (name, path, uri).
+ *
+ * Invalid values in these fields can cause security problems as reported in
+ * CVE-2018-11235 and and CVE-2018-17456
+ */
+public class SubmoduleValidator {
+
+	/**
+	 * Error validating a git submodule declaration
+	 */
+	public static class SubmoduleValidationException extends Exception {
+
+		/**
+		 * @param message
+		 *            Description of the problem
+		 */
+		public SubmoduleValidationException(String message) {
+			super(message);
+		}
+
+		private static final long serialVersionUID = 1L;
+	}
+
+	/**
+	 * Validate name for a submodule
+	 *
+	 * @param name
+	 *            name of a submodule
+	 * @throws SubmoduleValidationException
+	 *             name doesn't seem valid (detail in message)
+	 */
+	public static void assertValidSubmoduleName(String name)
+			throws SubmoduleValidationException {
+		if (name.contains("/../") || name.contains("\\..\\") //$NON-NLS-1$ //$NON-NLS-2$
+				|| name.startsWith("../") || name.startsWith("..\\") //$NON-NLS-1$ //$NON-NLS-2$
+				|| name.endsWith("/..") || name.endsWith("\\..")) { //$NON-NLS-1$ //$NON-NLS-2$
+			// Submodule names are used to store the submodule repositories
+			// under $GIT_DIR/modules. Having ".." in submodule names makes a
+			// vulnerability (CVE-2018-11235
+			// https://bugs.eclipse.org/bugs/show_bug.cgi?id=535027#c0)
+			// Reject names containing ".." path segments. We don't
+			// automatically replace these characters or canonicalize by
+			// regarding the name as a file path.
+			// Since Path class is platform dependent, we manually check '/' and
+			// '\\' patterns here.
+			throw new SubmoduleValidationException(MessageFormat
+					.format(JGitText.get().invalidNameContainsDotDot, name));
+		}
+
+		if (name.startsWith("-")) { //$NON-NLS-1$
+			throw new SubmoduleValidationException(
+					MessageFormat.format(
+							JGitText.get().submoduleNameInvalid, name));
+		}
+	}
+
+	/**
+	 * Validate URI for a submodule
+	 *
+	 * @param uri
+	 *            uri of a submodule
+	 * @throws SubmoduleValidationException
+	 *             uri doesn't seem valid
+	 */
+	public static void assertValidSubmoduleUri(String uri)
+			throws SubmoduleValidationException {
+		if (uri.startsWith("-")) { //$NON-NLS-1$
+			throw new SubmoduleValidationException(
+					MessageFormat.format(
+							JGitText.get().submoduleUrlInvalid, uri));
+		}
+	}
+
+	/**
+	 * Validate path for a submodule
+	 *
+	 * @param path
+	 *            path of a submodule
+	 * @throws SubmoduleValidationException
+	 *             path doesn't look right
+	 */
+	public static void assertValidSubmodulePath(String path)
+			throws SubmoduleValidationException {
+
+		if (path.startsWith("-")) { //$NON-NLS-1$
+			throw new SubmoduleValidationException(
+					MessageFormat.format(
+							JGitText.get().submodulePathInvalid, path));
+		}
+	}
+
+}