Windows PuTTYgen: support configurable fingerprint type.

The fingerprint type shown in the PuTTYgen main dialog can now be
selected from the Key menu. Also, I've widened the dialog box, because
SHA256 fingerprints are wider than MD5 ones.

(In a fixed-pitch font, the fingerprint itself is slightly shorter -
43 base64 characters in place of 47 characters of colon-separated hex.
But the "SHA256:" prefix lengthens it, and also, in a non-fixed-pitch
font such as the default one in Windows dialogs, the colons are very
narrow, so the MD5 fingerprint has a far smaller pixel width.)

windows/puttygen.rc

@@ -12,7 +12,7 @@
 
 200 ICON "puttygen.ico"
 
-201 DIALOG DISCARDABLE 0, 0, 318, 270
+201 DIALOG DISCARDABLE 0, 0, 400, 270
 STYLE DS_MODALFRAME | WS_POPUP | WS_CAPTION | WS_SYSMENU
 CAPTION "PuTTY Key Generator"
 FONT 8, "MS Shell Dlg"

windows/winpgen.c

@@ -603,6 +603,7 @@ struct MainDlgState {
     keytype keytype;
     const PrimeGenerationPolicy *primepolicy;
     bool rsa_strong;
+    FingerprintType fptype;
     char **commentptr;                 /* points to key.comment or ssh2key.comment */
     ssh2_userkey ssh2key;
     unsigned *entropy;
@@ -683,6 +684,7 @@ enum {
     IDC_KEYSSH2ECDSA, IDC_KEYSSH2EDDSA,
     IDC_PRIMEGEN_PROB, IDC_PRIMEGEN_MAURER_SIMPLE, IDC_PRIMEGEN_MAURER_COMPLEX,
     IDC_RSA_STRONG,
+    IDC_FPTYPE_SHA256, IDC_FPTYPE_MD5,
     IDC_PPK_PARAMS,
     IDC_BITSSTATIC, IDC_BITS,
     IDC_ECCURVESTATIC, IDC_ECCURVE,
@@ -892,6 +894,41 @@ void ui_set_rsa_strong(HWND hwnd, struct MainDlgState *state, bool enable)
     CheckMenuItem(state->keymenu, IDC_RSA_STRONG,
                   (enable ? MF_CHECKED : 0) | MF_BYCOMMAND);
 }
+static FingerprintType idc_to_fptype(int option)
+{
+    switch (option) {
+      case IDC_FPTYPE_SHA256:
+        return SSH_FPTYPE_SHA256;
+      case IDC_FPTYPE_MD5:
+        return SSH_FPTYPE_MD5;
+      default:
+        unreachable("bad control id in idc_to_fptype");
+    }
+}
+static int fptype_to_idc(FingerprintType fptype)
+{
+    switch (fptype) {
+      case SSH_FPTYPE_SHA256:
+        return IDC_FPTYPE_SHA256;
+      case SSH_FPTYPE_MD5:
+        return IDC_FPTYPE_MD5;
+      default:
+        unreachable("bad fptype in fptype_to_idc");
+    }
+}
+void ui_set_fptype(HWND hwnd, struct MainDlgState *state, int option)
+{
+    CheckMenuRadioItem(state->keymenu, IDC_FPTYPE_SHA256,
+                       IDC_FPTYPE_MD5, option, MF_BYCOMMAND);
+
+    state->fptype = idc_to_fptype(option);
+
+    if (state->key_exists && state->ssh2) {
+        char *fp = ssh2_fingerprint(state->ssh2key.key, state->fptype);
+        SetDlgItemText(hwnd, IDC_FINGERPRINT, fp);
+        sfree(fp);
+    }
+}
 
 void load_key_file(HWND hwnd, struct MainDlgState *state,
                    Filename *filename, bool was_import_cmd)
@@ -1023,7 +1060,7 @@ void load_key_file(HWND hwnd, struct MainDlgState *state,
 
                 savecomment = state->ssh2key.comment;
                 state->ssh2key.comment = NULL;
-                fp = ssh2_fingerprint(state->ssh2key.key, SSH_FPTYPE_DEFAULT);
+                fp = ssh2_fingerprint(state->ssh2key.key, state->fptype);
                 state->ssh2key.comment = savecomment;
 
                 SetDlgItemText(hwnd, IDC_FINGERPRINT, fp);
@@ -1164,6 +1201,11 @@ static INT_PTR CALLBACK MainDlgProc(HWND hwnd, UINT msg,
             AppendMenu(menu1, MF_SEPARATOR, 0, 0);
             AppendMenu(menu1, MF_ENABLED, IDC_PPK_PARAMS,
                        "Parameters for saving key files...");
+            AppendMenu(menu1, MF_SEPARATOR, 0, 0);
+            AppendMenu(menu1, MF_ENABLED, IDC_FPTYPE_SHA256,
+                       "Show fingerprint as SHA256");
+            AppendMenu(menu1, MF_ENABLED, IDC_FPTYPE_MD5,
+                       "Show fingerprint as MD5");
             AppendMenu(menu, MF_POPUP | MF_ENABLED, (UINT_PTR) menu1, "&Key");
             state->keymenu = menu1;
 
@@ -1222,15 +1264,15 @@ static INT_PTR CALLBACK MainDlgProc(HWND hwnd, UINT msg,
                         IDC_PKSTATIC, IDC_KEYDISPLAY, 5);
             SendDlgItemMessage(hwnd, IDC_KEYDISPLAY, EM_SETREADONLY, 1, 0);
             staticedit(&cp, "Key f&ingerprint:", IDC_FPSTATIC,
-                       IDC_FINGERPRINT, 75);
+                       IDC_FINGERPRINT, 82);
             SendDlgItemMessage(hwnd, IDC_FINGERPRINT, EM_SETREADONLY, 1,
                                0);
             staticedit(&cp, "Key &comment:", IDC_COMMENTSTATIC,
-                       IDC_COMMENTEDIT, 75);
+                       IDC_COMMENTEDIT, 82);
             staticpassedit(&cp, "Key p&assphrase:", IDC_PASSPHRASE1STATIC,
-                           IDC_PASSPHRASE1EDIT, 75);
+                           IDC_PASSPHRASE1EDIT, 82);
             staticpassedit(&cp, "C&onfirm passphrase:",
-                           IDC_PASSPHRASE2STATIC, IDC_PASSPHRASE2EDIT, 75);
+                           IDC_PASSPHRASE2STATIC, IDC_PASSPHRASE2EDIT, 82);
             endbox(&cp);
             beginbox(&cp, "Actions", IDC_BOX_ACTIONS);
             staticbtn(&cp, "Generate a public/private key pair",
@@ -1300,6 +1342,7 @@ static INT_PTR CALLBACK MainDlgProc(HWND hwnd, UINT msg,
         ui_set_key_type(hwnd, state, IDC_KEYSSH2RSA);
         ui_set_primepolicy(hwnd, state, IDC_PRIMEGEN_PROB);
         ui_set_rsa_strong(hwnd, state, false);
+        ui_set_fptype(hwnd, state, fptype_to_idc(SSH_FPTYPE_DEFAULT));
         SetDlgItemInt(hwnd, IDC_BITS, DEFAULT_KEY_BITS, false);
         SendDlgItemMessage(hwnd, IDC_ECCURVE, CB_SETCURSEL,
                            DEFAULT_ECCURVE_INDEX, 0);
@@ -1366,6 +1409,13 @@ static INT_PTR CALLBACK MainDlgProc(HWND hwnd, UINT msg,
             ui_set_primepolicy(hwnd, state, LOWORD(wParam));
             break;
           }
+          case IDC_FPTYPE_SHA256:
+          case IDC_FPTYPE_MD5: {
+            state = (struct MainDlgState *)
+                GetWindowLongPtr(hwnd, GWLP_USERDATA);
+            ui_set_fptype(hwnd, state, LOWORD(wParam));
+            break;
+          }
           case IDC_RSA_STRONG: {
             state = (struct MainDlgState *)
                 GetWindowLongPtr(hwnd, GWLP_USERDATA);
@@ -1796,7 +1846,7 @@ static INT_PTR CALLBACK MainDlgProc(HWND hwnd, UINT msg,
             savecomment = *state->commentptr;
             *state->commentptr = NULL;
             if (state->ssh2)
-                fp = ssh2_fingerprint(state->ssh2key.key, SSH_FPTYPE_DEFAULT);
+                fp = ssh2_fingerprint(state->ssh2key.key, state->fptype);
             else
                 fp = rsa_ssh1_fingerprint(&state->key);
             SetDlgItemText(hwnd, IDC_FINGERPRINT, fp);