Remove length restriction in key reader.

src/main/java/net/schmizz/sshj/userauth/keyprovider/PuTTYKeyFile.java

@@ -321,9 +321,6 @@ public void skip() throws IOException {
 
         private byte[] read() throws IOException {
             int len = di.readInt();
-            if (len <= 0 || len > 513) {
-                throw new IOException(String.format("Invalid length %d", len));
-            }
             byte[] r = new byte[len];
             di.readFully(r);
             return r;

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

@@ -28,6 +28,89 @@
 
 public class PuTTYKeyFileTest {
 
+    final static String ppk8192 = "PuTTY-User-Key-File-2: ssh-rsa\n" +
+            "Encryption: none\n" +
+            "Comment: imported-openssh-key\n" +
+            "Public-Lines: 22\n" +
+            "AAAAB3NzaC1yc2EAAAADAQABAAAEAQCcasi2SDVGvty6az32C3Uc3F4d8icjefnN\n" +
+            "YCaDnBIRQjczX118dT/nG2rEMygR/cgCxmZgcySC7vo5KUNjJhxCMHa5u4H0CVdy\n" +
+            "Raey2AOZBfLECjzuXSaakeMCIqyT6IywUBEFnkN6aUesyQtUUf1hR5iWHwPUmJPO\n" +
+            "uYLlE4uYnK5hkeH8fSEbYVPcPiBnrHtRk+zh9MF0RR6tK0Gcms5eLfF2V2MNytvU\n" +
+            "FnAySqX8mYISeJrg7v41PxtoEsAhGE88h4XAYX57uB4ewwTWQOlbBVgAutLybyLG\n" +
+            "rxbw+cDuC3ZOuxU78u5PykcS/mkE2wu1jUtdnCzAmNN8XobAft0wggiEZUBc+t9D\n" +
+            "2NmezZFU62SEkjxOWX/idDQrCQ8au8RQZhIgLYusGXDeeYFoPDk/4ObBxz3YkuTu\n" +
+            "UqzVTYwoUslTe8cz5J+hDGPeTudkt1K4uXa+3weXrzj0BnSYvGb01bfoam8lShdl\n" +
+            "MBg5hmow0ZjE6AvJgdttu+9SKvIp+jGQ2v2fv/m/LmGBKgZ5yslGJb6hhNf7MA5S\n" +
+            "ewgHuAk8kfZ9yZIa3UcQDim8yxOkB/Y3885MFpdZqg3XNPCNo0s1SimGGRbngWwg\n" +
+            "AxhKT24OzQ+WZn+rU7mlXHT4RehrYNKNukZlwqnSksg+TJ1ZGoj8mfUbAHmz0UnB\n" +
+            "DQ7dpNP1DhAKxiFjgHfkDfmF4Bic7I1eHSesigCKImH7Zoomp1NcH0bub3h+Owyp\n" +
+            "2fk5evgMBtuGvGGFuCzgyZeeiX6hzOgKyaqCML88OgNSjSMFkdiBYd0rwufimkID\n" +
+            "v+vH1uIEcVZ69sn8xg0Vh7U/0aB2mai0EYcDuTa78gqkeSGp8AS+IgahgdwV/HQX\n" +
+            "aLC/QFRgFb/NX2YmzKsVYWdObBamkbaJAOfrXb5vEuAyU2aRQouqKH4tYDNpkBYg\n" +
+            "8KCq9A/8z8sS1Gwe3UHU9gZOEuTAI7JQQCN7E3U3JuuCFks2jAoh7WE3KxqEu9Lq\n" +
+            "sMJn9YRobGyPPMMcQJSAqMUpwEyup8ovI/3v5NRvw+ZSiM4wHyYqzODJu/U6H5Cj\n" +
+            "wq+MFCg4JcalRA/qKG4P9QVD9MfyqcX/AYWhdYj18BqstwUVtonhT0kMkKBx9ggU\n" +
+            "g/TvVKePf/wX0glqXXw59I1EIzCnxL8QWMkULDkk5GvzSrGFpR04IdOzsz5DMdL3\n" +
+            "p8bXOHK+04Rd/VG8w/f7eLfYid875B7m+kG9TKQzAT3lc8cmJ98gRzCG+pTIpzVB\n" +
+            "QM2nj4f8DenS1uAO23cXICR9Zyo98/dCv0xYc7g0Gp5HxppRuNLga9bBSg5dferT\n" +
+            "QvmP/MTgeNxiKepKFLakVT0MiM6QUlGfV35F6vDL1oQnQlp4OD7H\n" +
+            "Private-Lines: 54\n" +
+            "AAAEAEM55e/qEvPH/kgk5WmFPR1dXRoTxFyMBSAOzh7MijtesSjkOOLP5donP3j5\n" +
+            "36Pz5e3DZabYdf3MRkEhCfRoIccU20IyY8UF6s6TP2MvUkSHePJm0A9Ge9v9DYsS\n" +
+            "agfb7/OrRdWbUrce3o5Vjgf8gSE5S0xiIhxSQ1ybALYB84Jw/MW0lGMXSI5jA07q\n" +
+            "aLUGPa4vHKV0s1yMhIW6zKVJJ570sg3BuzHnWRnLVwdWbAan126m5TH9pcYuzFGr\n" +
+            "lWXj89I5EPRBMsJrvI5OFRscpO7Y2hzeLuHBgDnScNK7FP96b6ug3px4aZJjhq6U\n" +
+            "J4DNwDeUdarS/6z7QhH28oVzQQ+jI5P7jHEp5aFcZxPImEjeLsKHs2GdN8iVVwKU\n" +
+            "DyjXQKWpaOrpiFk8SfVkVYj+MUDSIXtxbZRSdhAz+lJm1PFTu3GlBlW4Uh8+mwGl\n" +
+            "+e+glu4L0AxzAOlhhuHikGRAvSNHY5aBgCmPsYRs6kx3B9bZjoY6kS5XIH8GQfKX\n" +
+            "wKLoBDuU02LAeM+BWKjR7hyUWnNKr6bt2IH+AnnSpP3kTBv7Q+yGIMRpDCzLWYbp\n" +
+            "5RQf0+PyZlzvbLc9zlsLRsQpRZ6utDANQnnXdyg/DEaL4up7mdJzVTXGc0it9xvp\n" +
+            "t93GrFf7klwUETcOnP+hoBL2w5+FcAHd73CoZ8GQIi6CtBJi/85EQ3IfyEXBF5l/\n" +
+            "NVtZt14uS+u4XNQFKiMKQnRyZ8I4iz/Ybd8FLvtmiL6kI6Poe92FRFRwLSpqZrYi\n" +
+            "WLcuVkFy7wzPOvS+gTbSFTP0xYIidqmjWBrabjxM1a2XUglcFL1lRGMt5pvHsDrz\n" +
+            "dDmWZZp2d+Z2AZwL1GdUA8LPaNp+rbkQeeOlu2FGFgBvrt9cmRG7DJWLGf/wLuuC\n" +
+            "hSGLOw6ZwVaPqNAuz7esnIUSeA0QdN1gssRhzGnuiDFoN9uirefhuZH6hfFNRRgo\n" +
+            "Bm+6cpuzybZYsPE3/+PIEjyTAhJZtGUIuDiqwyLw4rsoK1hKMEkWfe42U6eqCFea\n" +
+            "xPIvulUSkjcNa1Xg8SU6uNamlIz4RwAgS/cvmlmyZuzTiaYughl9xZ1/cHCCwFts\n" +
+            "Aj8kBuj3s/4GgVx7Q4YV0hUJ9OKRahiTGrOg53Hm7akkMIljqUVM9NNjYBZR/l9N\n" +
+            "Bk/KeLspTawHp3XaUdu8HVoDIJn4y2nEMcbhC30I2KEMpZR7cIrWO8lxKg6REJp8\n" +
+            "FM+PpkR8VS9nPuU7IFCnxdnlH3XUGsR7tIOhpxhNujxOEH686mgCigR8m1GVD69W\n" +
+            "5vE+mDmPGaZiPuNUIu7pCVA7nihPeH+Hyn9L8jJQkJXrwm4Y2bo6L8hT0Wm2o1C6\n" +
+            "WoDadMMrioP9hWwacXmfWp48MCEAAAIBAM4gEFhRnSmxl7CMXOI7PWRtp7T2spp4\n" +
+            "lPSJIlo7+DE6B+8AGXskGAnJOc8KBNQominGFeoQ6QaEOxajo3wsGgddHjlAAoFX\n" +
+            "JorUImC8Tbb4XGXGRI88IF0jgOvvRpHeuL952IjLUzNnXaETwCwZw3Q0iMMPTAHi\n" +
+            "VOQLJyFmwkfKVKpMN3/IsoHVCq3oMl2vg9/FYzO6U+s6g9PMC9eV7jx4fh+6hf/9\n" +
+            "mkC4QS5cBUWqI1JnwzuOEBSSsDFhN765yB6jiROezMgnkJqZxb6W2zLtDBEYbkFS\n" +
+            "keYRfbRRs3QCqxs30rxCFYuzg5kE9/7S0A5nUvI1pCgfR1Fri/ah/UTBi4c9hTPA\n" +
+            "2UpyRzQ23NcruAacTIYJpLctFVU1rgabGFzDlWeEKuY2kR/egt9Wykr3ACk26NdD\n" +
+            "IvmuxBJg46PH4M6vmthGE4ZRewmFzAFjbJC0LHKSgne1XWli58ELyiFd3pRp4sYF\n" +
+            "Zi4iWqYv2KGcRNxtgDoGstD1aEdOpribKcDdWIAba/zuTR9T36+L5gSmGf30VyX9\n" +
+            "ZbdG+Up96p913WktXo4Li+C2k70Lu49w4xW9CIO4pCOEe5wzp3MSbonkKdg//u93\n" +
+            "hEtYPUaBU9UYUnAWLfu0VKh2TuDsLbN7gEziI5vPkRyyisT7w7s1VSMwpdhtRtZz\n" +
+            "aaPsOaGBwXuXAAACAQDCQ6tPD3Dk2H/Q2oychhoN2NJ/K7NP0On+doZ8ACAhciHW\n" +
+            "KzbvsmVps3yZfhRRBa23c3oyeeKYFRsKW/b4a8z8QVvI8rmgoAQsw6R/uHdLvmiI\n" +
+            "1i8DiIYwr9SI/7e3O9Up5l7G5rzAhp3w2QvWDmC7h48R1gj1P0jbye6EDvsis14v\n" +
+            "s34VoKBJyr9NdlOwXtTRdYeRjJpYYVuSzZuZNvihyuJpz7Zd81L6imstcNfC3Tu7\n" +
+            "FVDEg9ER0VXkUrh2IHFZ+je6cTZwdoj/ynetti0u41KPevQr3lIQbhQvkXuTjkwE\n" +
+            "zpMPdU9PiMrTURh+C7aFCzH6z6/my6XjvJOZLbvLRGEhHMTDPFCsmPmlYGSpbryx\n" +
+            "T626I5rtcmFnCEJ2jv2mvTqV79i0OsFUHyi61krV07HO9C7+6Bm8r7zxGVNlFMjX\n" +
+            "I+Gs4XF4fkH0b8dvudRpNVQ5+ze3scBL3gCJNGEhmFHmKdosQ2eFwJi17Y6Cx2Tp\n" +
+            "Epj1gMDlsBVnEVnV1Mz9tnpZ3OuTaCyAyrbA0XrmfgmFaqIOdcqXTHiE6aaHRDlw\n" +
+            "mkVbYyel2WKmtRwi9k9Fy0CdJdA6ATY2QBK/MaayTjP+d0By/4sGPsfYn8Cu5I8l\n" +
+            "cGvvQnuPwnnT2kF9qONLcY5otChtJprFga5evBxU6HX+J+TKy75JabcFv1V8UQAA\n" +
+            "AgBM3f5IfW1XTRP4EGO18lt1DwdRhy84UdsQaWm/pnAhojOqNMAB2R5OL3bJ+nit\n" +
+            "9792p54MgFuX94c8RL34fryeD/zWudwxVo+upcs7rzW+1xG6uYa581qVhfJEOHA8\n" +
+            "a4zk7PzrHKW8cmOK5HYBDSXUkGtFRxkqirJeOSGAx6YXhpVuvZfPACYPrl8wjeg7\n" +
+            "JWJ2O2rDes2pauK5aIGvkc6CarrPTTWzDbw9M1EzmVzcr/R2GTdDBPD4sQ1AAHto\n" +
+            "Io4cOGfdtw0pFrmi5Qu+TSgt7xY4dK+IXTHtUz4FY1OpPNEWBhdbYNGVWDWwQj6z\n" +
+            "LibcD5tpfVKzNNczqN5RG9jVu4Jh0vbRaAUW6E4BaWZZ2qh/m5DxAjeewjEyWCFK\n" +
+            "2yqD8puzikGTquWBf87azdPbYK0qo5tnvBFhLOee2+mhC+++yWIZT7z/XIWCM2i6\n" +
+            "K4jy2qInjrHBamXtYOep776OTY3fvgoYqYBHrT2+tbHIHhBxcHdkxS8qwkfzkg40\n" +
+            "5WYmVed7rWvG6xu6XJIWnn7HXVGKogUdPOPyv+qHz+TcqVCwVRVEa0eTX9gaBztr\n" +
+            "ttGrDrR3676T2xwsWjeZlSpL9oF1ZH8faxZPUHoT8z9Zhgl0dbOt/pPXZiTRM8VS\n" +
+            "erB/l04ZPmqU7zzGXFgpRGaXsOEO9TRpiw3+sragQN/ixg==\n" +
+            "Private-MAC: 5405ff514dd17380c68d08f371a9497e827a1054\n";
+
     final static String ppk2048 = "PuTTY-User-Key-File-2: ssh-rsa\n" +
             "Encryption: none\n" +
             "Comment: \n" +
@@ -155,6 +238,14 @@ public void test4096() throws Exception {
         assertNotNull(key.getPublic());
     }
 
+    @Test
+    public void test8192() throws Exception {
+        PuTTYKeyFile key = new PuTTYKeyFile();
+        key.init(new StringReader(ppk8192));
+        assertNotNull(key.getPrivate());
+        assertNotNull(key.getPublic());
+    }
+
     @Test
     public void testCorrectPassphraseRsa() throws Exception {
         PuTTYKeyFile key = new PuTTYKeyFile();