ObjectChecker: Disallow Windows shortname "GIT~1"

Windows creates shortnames for all non-8.3 files (see [1]). Hence we
need to disallow all names which could potentially be a shortname for
".git". Example: in an empty directory create a folder "GIT~1". Now you
can't create another folder ".git".

The path "GIT~1" may map to ".git" on Windows. A potential victim to
such an attack first has to initialize a git repository in order to
receive any git commits. Hence the .git folder created by init will get
the shortname "GIT~1". ".git" will only get a different shortname if the
user has created a file "GIT~1" before initialization of the git
repository.

[1] http://en.wikipedia.org/wiki/8.3_filename

Change-Id: I9978ab8f2d2951c46c1b9bbde57986d64d26b9b2
Signed-off-by: Christian Halstrick <christian.halstrick@sap.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ObjectCheckerTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ObjectCheckerTest.java
index aa17ac32cf..8a782b7ffd 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ObjectCheckerTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ObjectCheckerTest.java
@@ -1404,6 +1404,40 @@ public class ObjectCheckerTest {
 	}
 
 	@Test
+	public void testInvalidTreeNameIsGITTilde1() {
+		StringBuilder b = new StringBuilder();
+		entry(b, "100644 GIT~1");
+		byte[] data = Constants.encodeASCII(b.toString());
+		try {
+			checker.checkTree(data);
+			fail("incorrectly accepted an invalid tree");
+		} catch (CorruptObjectException e) {
+			assertEquals("invalid name 'GIT~1'", e.getMessage());
+		}
+	}
+
+	@Test
+	public void testInvalidTreeNameIsGiTTilde1() {
+		StringBuilder b = new StringBuilder();
+		entry(b, "100644 GiT~1");
+		byte[] data = Constants.encodeASCII(b.toString());
+		try {
+			checker.checkTree(data);
+			fail("incorrectly accepted an invalid tree");
+		} catch (CorruptObjectException e) {
+			assertEquals("invalid name 'GiT~1'", e.getMessage());
+		}
+	}
+
+	@Test
+	public void testValidTreeNameIsGitTilde11() throws CorruptObjectException {
+		StringBuilder b = new StringBuilder();
+		entry(b, "100644 GIT~11");
+		byte[] data = Constants.encodeASCII(b.toString());
+		checker.checkTree(data);
+	}
+
+	@Test
 	public void testInvalidTreeTruncatedInName() {
 		final StringBuilder b = new StringBuilder();
 		b.append("100644 b");