Fix a segfault (addr->error was unpredictable following a dotted-dec lookup)

[u/mdw/putty] / puttygen.c

diff --git a/puttygen.c b/puttygen.c
index 9b36090..2d6653a 100644 (file)
--- a/puttygen.c
+++ b/puttygen.c
@@ -5,10 +5,8 @@
 #include <windows.h>
 #include <commctrl.h>
 #include <time.h>
-#ifndef NO_SECURITY
-#include <aclapi.h>
-#endif
 #include <stdio.h>
+#include <stdlib.h>
 
 #define PUTTY_DO_GLOBALS
 
@@ -18,13 +16,7 @@
 
 #define WM_DONEKEY (WM_XUSER + 1)
 
-#define KEYSIZE 1024
-
-/*
- * TODO:
- *  - test the generated keys for actual working-RSA-key-hood
- *  - variable key size
- */
+#define DEFAULT_KEYSIZE 1024
 
 /* ----------------------------------------------------------------------
  * Progress report code. This is really horrible :-)
@@ -234,6 +226,7 @@ static int CALLBACK AboutProc (HWND hwnd, UINT msg,
 struct rsa_key_thread_params {
     HWND progressbar;                  /* notify this with progress */
     HWND dialog;                       /* notify this on completion */
+    int keysize;                      /* bits in key */
     struct RSAKey *key;
     struct RSAAux *aux;
 };
@@ -243,7 +236,8 @@ static DWORD WINAPI generate_rsa_key_thread(void *param) {
     struct progress prog;
     prog.progbar = params->progressbar;
 
-    rsa_generate(params->key, params->aux, KEYSIZE, progress_update, &prog);
+    rsa_generate(params->key, params->aux,
+                params->keysize, progress_update, &prog);
 
     PostMessage(params->dialog, WM_DONEKEY, 0, 0);
 
@@ -256,6 +250,7 @@ struct MainDlgState {
     int generation_thread_exists;
     int key_exists;
     int entropy_got, entropy_required, entropy_size;
+    int keysize;
     unsigned *entropy;
     struct RSAKey key;
     struct RSAAux aux;
@@ -305,6 +300,8 @@ static int CALLBACK MainDlgProc (HWND hwnd, UINT msg,
         IDC_GENSTATIC, IDC_GENERATE,
         IDC_LOADSTATIC, IDC_LOAD,
         IDC_SAVESTATIC, IDC_SAVE,
+        IDC_BOX_PARAMS, IDC_BOXT_PARAMS,
+        IDC_BITSSTATIC, IDC_BITS,
         IDC_ABOUT,
     };
     static const int nokey_ids[] = { IDC_NOKEY, 0 };
@@ -318,13 +315,15 @@ static int CALLBACK MainDlgProc (HWND hwnd, UINT msg,
     static const char generating_msg[] =
         "Please wait while a key is generated...";
     static const char entropy_msg[] =
-        "Please move the mouse in this window to generate randomness";
+        "Please generate some randomness by moving the mouse over the blank area.";
     struct MainDlgState *state;
 
     switch (msg) {
       case WM_INITDIALOG:
         state = malloc(sizeof(*state));
         state->generation_thread_exists = FALSE;
+        state->collecting_entropy = FALSE;
+        state->entropy = NULL;
         state->key_exists = FALSE;
         SetWindowLong(hwnd, GWL_USERDATA, (LONG)state);
         {
@@ -366,7 +365,14 @@ static int CALLBACK MainDlgProc (HWND hwnd, UINT msg,
             staticbtn(&cp, "Save the generated key to a new file",
                       IDC_SAVESTATIC, "&Save", IDC_SAVE);
             endbox(&cp);
+            beginbox(&cp, "Parameters",
+                     IDC_BOX_PARAMS, IDC_BOXT_PARAMS);
+            staticedit(&cp, "Number of &bits in a generated key:",
+                      IDC_BITSSTATIC, IDC_BITS, 20);
+            endbox(&cp);
         }
+       SetDlgItemInt(hwnd, IDC_BITS, DEFAULT_KEYSIZE, FALSE);
+
         /*
          * Initially, hide the progress bar and the key display,
          * and show the no-key display. Also disable the Save
@@ -381,7 +387,9 @@ static int CALLBACK MainDlgProc (HWND hwnd, UINT msg,
        return 1;
       case WM_MOUSEMOVE:
         state = (struct MainDlgState *)GetWindowLong(hwnd, GWL_USERDATA);
-        if (state->collecting_entropy) {
+        if (state->collecting_entropy &&
+            state->entropy &&
+            state->entropy_got < state->entropy_required) {
             state->entropy[state->entropy_got++] = lParam;
             state->entropy[state->entropy_got++] = GetMessageTime();
             SendDlgItemMessage(hwnd, IDC_PROGRESS, PBM_SETPOS,
@@ -396,6 +404,7 @@ static int CALLBACK MainDlgProc (HWND hwnd, UINT msg,
                 random_add_heavynoise(state->entropy, state->entropy_size);
                 memset(state->entropy, 0, state->entropy_size);
                 free(state->entropy);
+                state->collecting_entropy = FALSE;
 
                 SetDlgItemText(hwnd, IDC_GENERATING, generating_msg);
                 SendDlgItemMessage(hwnd, IDC_PROGRESS, PBM_SETRANGE, 0,
@@ -405,6 +414,7 @@ static int CALLBACK MainDlgProc (HWND hwnd, UINT msg,
                 params = malloc(sizeof(*params));
                 params->progressbar = GetDlgItem(hwnd, IDC_PROGRESS);
                 params->dialog = hwnd;
+               params->keysize = state->keysize;
                 params->key = &state->key;
                 params->aux = &state->aux;
 
@@ -416,7 +426,6 @@ static int CALLBACK MainDlgProc (HWND hwnd, UINT msg,
                     free(params);
                 } else {
                     state->generation_thread_exists = TRUE;
-                    state->collecting_entropy = FALSE;
                 }
             }
         }
@@ -446,6 +455,22 @@ static int CALLBACK MainDlgProc (HWND hwnd, UINT msg,
           case IDC_GENERATE:
             state = (struct MainDlgState *)GetWindowLong(hwnd, GWL_USERDATA);
             if (!state->generation_thread_exists) {
+                BOOL ok;
+                state->keysize = GetDlgItemInt(hwnd, IDC_BITS,
+                                               &ok, FALSE);
+                if (!ok) state->keysize = DEFAULT_KEYSIZE;
+                if (state->keysize < 256) {
+                    int ret = MessageBox(hwnd,
+                                         "PuTTYgen will not generate a key"
+                                         " smaller than 256 bits.\n"
+                                         "Key length reset to 256. Continue?",
+                                         "PuTTYgen Warning",
+                                         MB_ICONWARNING | MB_OKCANCEL);
+                    if (ret != IDOK)
+                        break;
+                    state->keysize = 256;
+                    SetDlgItemInt(hwnd, IDC_BITS, 256, FALSE);
+                }
                 hidemany(hwnd, nokey_ids, TRUE);
                 hidemany(hwnd, generating_ids, FALSE);
                 hidemany(hwnd, gotkey_ids, TRUE);
@@ -458,16 +483,18 @@ static int CALLBACK MainDlgProc (HWND hwnd, UINT msg,
 
                 /*
                  * My brief statistical tests on mouse movements
-                 * suggest that there are about 5 bits of
-                 * randomness in the x position, 5 in the y
+                 * suggest that there are about 2.5 bits of
+                 * randomness in the x position, 2.5 in the y
                  * position, and 1.7 in the message time, making
-                 * 11.7 bits of unpredictability per mouse
-                 * movement. However, other people have told me
-                 * it's far less than that, so I'm going to be
-                 * stupidly cautious and knock that down to a nice
-                 * round 4.
+                 * 5.7 bits of unpredictability per mouse movement.
+                 * However, other people have told me it's far less
+                 * than that, so I'm going to be stupidly cautious
+                 * and knock that down to a nice round 2. With this
+                 * method, we require two words per mouse movement,
+                 * so with 2 bits per mouse movement we expect 2
+                 * bits every 2 words.
                  */
-                state->entropy_required = (KEYSIZE / 4) * 2;
+                state->entropy_required = (state->keysize/2) * 2;
                 state->entropy_got = 0;
                 state->entropy_size = (state->entropy_required *
                                        sizeof(*state->entropy));