Ensure that ~ in ssh config is replaced before Jsch sees it

Do tilde replacement for values from the ssh config file that are
file names in all cases to make sure that they are already replaced
when Jsch tries to get the values.

Previously, OpenSshConfig did tilde replacement only for the
IdentityFile in the JGit-facing "Host" interface and left the
replacement in the Jsch-facing "Config" interface to Jsch.

But on Windows the JGit notion of what should be used to replace the
tilde differs from Jsch's replacement. Jsch always replaces the tilde
by the value of the system property "user.home", whereas JGit also
considers some environment variables like %HOME%. This can lead to
rather surprising failures as in the case of bug 526175 where
%HOME% != user.home.

Prior to commit 9d24470 (i.e.,prior to JGit 4.9.0) this problem never
occurred because Jsch was completely unaware of the ssh config file
and all host and IdentityFile handling happened exclusively in JGit.

Bug: 526175
Change-Id: I1511699664ffea07cb58ed751cfdb79b15e3a99e
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/OpenSshConfigTest.java

@@ -323,11 +323,12 @@ public class OpenSshConfigTest extends RepositoryTestCase {
 
 	@Test
 	public void testListValueMultiple() throws Exception {
-		// Tilde expansion doesn't occur within the parser
+		// Tilde expansion occurs within the parser
 		config("Host orcz\nUserKnownHostsFile \"~/foo/ba z\" /foo/bar \n");
 		final ConfigRepository.Config c = osc.getConfig("orcz");
 		assertNotNull(c);
-		assertArrayEquals(new Object[] { "~/foo/ba z", "/foo/bar" },
+		assertArrayEquals(new Object[] { new File(home, "foo/ba z").getPath(),
+				"/foo/bar" },
 				c.getValues("UserKnownHostsFile"));
 	}
 
@@ -371,8 +372,9 @@ public class OpenSshConfigTest extends RepositoryTestCase {
 		// Host does tilde replacement
 		assertEquals(new File(home, "foo/ba z"), f);
 		final ConfigRepository.Config c = h.getConfig();
-		// Config doesn't
-		assertArrayEquals(new Object[] { "~/foo/ba z", "/foo/bar" },
+		// Config does tilde replacement, too
+		assertArrayEquals(new Object[] { new File(home, "foo/ba z").getPath(),
+				"/foo/bar" },
 				c.getValues("IdentityFile"));
 	}
 
@@ -386,8 +388,9 @@ public class OpenSshConfigTest extends RepositoryTestCase {
 		// Host does tilde replacement
 		assertEquals(new File(home, "foo/ba z"), f);
 		final ConfigRepository.Config c = h.getConfig();
-		// Config doesn't
-		assertArrayEquals(new Object[] { "~/foo/ba z", "/foo/bar", "/foo/baz" },
+		// Config does tilde replacement, too
+		assertArrayEquals(new Object[] { new File(home, "foo/ba z").getPath(),
+				"/foo/bar", "/foo/baz" },
 				c.getValues("IdentityFile"));
 	}
 
@@ -397,7 +400,7 @@ public class OpenSshConfigTest extends RepositoryTestCase {
 		final Host h = osc.lookup("repo.or.cz");
 		assertNotNull(h);
 		assertEquals(new File(home, "foo/bar"), h.getIdentityFile());
-		assertArrayEquals(new Object[] { "~/foo/bar" },
+		assertArrayEquals(new Object[] { new File(home, "foo/bar").getPath() },
 				h.getConfig().getValues("IdentityFile"));
 	}
 
@@ -407,7 +410,8 @@ public class OpenSshConfigTest extends RepositoryTestCase {
 		final Host h = osc.lookup("repo.or.cz");
 		assertNotNull(h);
 		assertEquals(new File(home, "foo/bar"), h.getIdentityFile());
-		assertArrayEquals(new Object[] { "~/foo/bar", "/foo/baz" },
+		assertArrayEquals(new Object[] { new File(home, "foo/bar").getPath(),
+				"/foo/baz" },
 				h.getConfig().getValues("IdentityFile"));
 	}
 
@@ -417,12 +421,13 @@ public class OpenSshConfigTest extends RepositoryTestCase {
 		final Host h1 = osc.lookup("repo.or.cz");
 		assertNotNull(h1);
 		assertEquals(new File(home, "foo/bar"), h1.getIdentityFile());
-		assertArrayEquals(new Object[] { "~/foo/bar", "/foo/baz" },
+		assertArrayEquals(new Object[] { new File(home, "foo/bar").getPath(),
+				"/foo/baz" },
 				h1.getConfig().getValues("IdentityFile"));
 		final Host h2 = osc.lookup("orcz");
 		assertNotNull(h2);
 		assertEquals(new File(home, "foo/bar"), h2.getIdentityFile());
-		assertArrayEquals(new Object[] { "~/foo/bar" },
+		assertArrayEquals(new Object[] { new File(home, "foo/bar").getPath() },
 				h2.getConfig().getValues("IdentityFile"));
 	}
 

org.eclipse.jgit/src/org/eclipse/jgit/transport/OpenSshConfig.java

@@ -352,6 +352,17 @@ public class OpenSshConfig implements ConfigRepository {
 		return Boolean.FALSE;
 	}
 
+	private static File toFile(String path, File home) {
+		if (path.startsWith("~/")) { //$NON-NLS-1$
+			return new File(home, path.substring(2));
+		}
+		File ret = new File(path);
+		if (ret.isAbsolute()) {
+			return ret;
+		}
+		return new File(home, path);
+	}
+
 	private static int positive(final String value) {
 		if (value != null) {
 			try {
@@ -730,25 +741,48 @@ public class OpenSshConfig implements ConfigRepository {
 			return result;
 		}
 
+		private List<String> replaceTilde(List<String> values, File home) {
+			List<String> result = new ArrayList<>(values.size());
+			for (String value : values) {
+				result.add(toFile(value, home).getPath());
+			}
+			return result;
+		}
+
 		protected void substitute(String originalHostName, File home) {
 			Replacer r = new Replacer(originalHostName, home);
 			if (multiOptions != null) {
 				List<String> values = multiOptions.get("IDENTITYFILE"); //$NON-NLS-1$
 				if (values != null) {
 					values = substitute(values, "dhlru", r); //$NON-NLS-1$
+					values = replaceTilde(values, home);
 					multiOptions.put("IDENTITYFILE", values); //$NON-NLS-1$
 				}
 				values = multiOptions.get("CERTIFICATEFILE"); //$NON-NLS-1$
 				if (values != null) {
 					values = substitute(values, "dhlru", r); //$NON-NLS-1$
+					values = replaceTilde(values, home);
 					multiOptions.put("CERTIFICATEFILE", values); //$NON-NLS-1$
 				}
 			}
+			if (listOptions != null) {
+				List<String> values = listOptions.get("GLOBALKNOWNHOSTSFILE"); //$NON-NLS-1$
+				if (values != null) {
+					values = replaceTilde(values, home);
+					listOptions.put("GLOBALKNOWNHOSTSFILE", values); //$NON-NLS-1$
+				}
+				values = listOptions.get("USERKNOWNHOSTSFILE"); //$NON-NLS-1$
+				if (values != null) {
+					values = replaceTilde(values, home);
+					listOptions.put("USERKNOWNHOSTSFILE", values); //$NON-NLS-1$
+				}
+			}
 			if (options != null) {
 				// HOSTNAME already done in Replacer constructor
 				String value = options.get("IDENTITYAGENT"); //$NON-NLS-1$
 				if (value != null) {
 					value = r.substitute(value, "dhlru"); //$NON-NLS-1$
+					value = toFile(value, home).getPath();
 					options.put("IDENTITYAGENT", value); //$NON-NLS-1$
 				}
 			}
@@ -909,17 +943,6 @@ public class OpenSshConfig implements ConfigRepository {
 			}
 		}
 
-		private File toFile(String path, File home) {
-			if (path.startsWith("~/")) { //$NON-NLS-1$
-				return new File(home, path.substring(2));
-			}
-			File ret = new File(path);
-			if (ret.isAbsolute()) {
-				return ret;
-			}
-			return new File(home, path);
-		}
-
 		Config getConfig() {
 			return config;
 		}