fix exception when parsing max possible date (#513)

* fix exception when parsing max possible date

* added test with rsa cert with large date

src/main/java/net/schmizz/sshj/common/KeyType.java

@@ -315,8 +315,8 @@ public enum KeyType {
                 builder.type(buf.readUInt32());
                 builder.id(buf.readString());
                 builder.validPrincipals(unpackList(buf.readBytes()));
-                builder.validAfter(dateFromEpoch(buf.readUInt64()));
-                builder.validBefore(dateFromEpoch(buf.readUInt64()));
+                builder.validAfter(dateFromEpoch(buf.readUInt64AsBigInteger()));
+                builder.validBefore(dateFromEpoch(buf.readUInt64AsBigInteger()));
                 builder.critOptions(unpackMap(buf.readBytes()));
                 builder.extensions(unpackMap(buf.readBytes()));
                 buf.readString(); // reserved
@@ -364,8 +364,13 @@ public enum KeyType {
             return ((Certificate<PublicKey>) key);
         }
 
-        private static Date dateFromEpoch(long seconds) {
-            return new Date(seconds * 1000);
+        private static Date dateFromEpoch(BigInteger seconds) {
+            BigInteger maxValue = BigInteger.valueOf(Long.MAX_VALUE / 1000);
+            if (seconds.compareTo(maxValue) > 0) {
+                return new Date(maxValue.longValue() * 1000);
+            } else {
+                return new Date(seconds.longValue() * 1000);
+            }
         }
 
         private static long epochFromDate(Date date) {

src/test/java/net/schmizz/sshj/keyprovider/OpenSSHKeyFileTest.java

@@ -264,6 +264,19 @@ public class OpenSSHKeyFileTest {
 
     }
 
+    @Test
+    public void shouldSuccessfullyLoadSignedRSAPublicKeyWithMaxDate() throws IOException {
+        FileKeyProvider keyFile = new OpenSSHKeyFile();
+        keyFile.init(new File("src/test/resources/keytypes/certificate/test_rsa_max_date"),
+                PasswordUtils.createOneOff(correctPassphrase));
+        PublicKey pubKey = keyFile.getPublic();
+
+        @SuppressWarnings("unchecked")
+        Certificate<RSAPublicKey> certificate = (Certificate<RSAPublicKey>) pubKey;
+
+        assertTrue(parseDate("9999-04-11 18:09:27 -0400").before(certificate.getValidBefore()));
+    }
+
     @Test
     public void shouldSuccessfullyLoadSignedDSAPublicKey() throws IOException {
         FileKeyProvider keyFile = new OpenSSHKeyFile();

src/test/resources/keytypes/certificate/test_rsa_max_date

@@ -0,0 +1,30 @@
+-----BEGIN RSA PRIVATE KEY-----
+Proc-Type: 4,ENCRYPTED
+DEK-Info: AES-128-CBC,5F1AEDBE1E9E4D83EBD9C7B71CD84DB5
+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-----END RSA PRIVATE KEY-----

src/test/resources/keytypes/certificate/test_rsa_max_date-cert.pub

@@ -0,0 +1 @@
+ssh-rsa-cert-v01@openssh.com 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 adami@computer