Changed default algo and size.

2 files changed, 145 insertions, 86 deletions

diff --git a/g10/ChangeLog b/g10/ChangeLog
index 1f9751293..ef6817037 100644
--- a/g10/ChangeLog
+++ b/g10/ChangeLog
@@ -1,3 +1,12 @@
+2009-05-17  Werner Koch  <wk@g10code.com>
+
+	* keygen.c (ask_algo): Add arg R_SUBKEY_ALGO.  Change return value
+	semantics.  Change presented order of algorithms.  Make RSA+RSA
+	the default.
+	(generate_keypair): Adjust for change.
+	(ask_keysize): Add arg PRIMARY_KEYSIZE for subkey creation.
+	Change callers.
+
 2009-05-15  Werner Koch  <wk@g10code.com>
 
 	* keygen.c (gen_card_key_with_backup): Get the size of the key
diff --git a/g10/keygen.c b/g10/keygen.c
index 96c68334e..1be65c42e 100644
--- a/g10/keygen.c
+++ b/g10/keygen.c
@@ -1636,94 +1636,141 @@ ask_key_flags(int algo,int subkey)
 }
 
 
-/****************
- * Returns: 0 to create both a DSA and a Elgamal key.
- *          and only if key flags are to be written the desired usage.
- */
+/* Ask for an algorithm.  The function returns the algorithm id to
+ * create. If ADDMODE is false the function won't show an option to
+ * create the primary and subkey combined and won't set R_USAGE
+ * either.  If a combined algorithm has been selected, the subkey
+ * algorithm is stored at R_SUBKEY_ALGO.  */
 static int
-ask_algo (int addmode, unsigned int *r_usage)
+ask_algo (int addmode, int *r_subkey_algo, unsigned int *r_usage)
 {
-    char *answer;
-    int algo;
-
-    *r_usage = 0;
-    tty_printf(_("Please select what kind of key you want:\n"));
-    if( !addmode )
-	tty_printf(_("   (%d) DSA and Elgamal (default)\n"), 1 );
-    tty_printf(    _("   (%d) DSA (sign only)\n"), 2 );
-    if (opt.expert)
-      tty_printf(  _("   (%d) DSA (set your own capabilities)\n"), 3 );
-    if( addmode )
-	tty_printf(_("   (%d) Elgamal (encrypt only)\n"), 4 );
-    tty_printf(    _("   (%d) RSA (sign only)\n"), 5 );
-    if (addmode)
-        tty_printf(_("   (%d) RSA (encrypt only)\n"), 6 );
-    if (opt.expert)
-      tty_printf(  _("   (%d) RSA (set your own capabilities)\n"), 7 );
+  char *answer;
+  int algo;
+  int dummy_algo;
 
-    for(;;) {
-	answer = cpr_get("keygen.algo",_("Your selection? "));
-	cpr_kill_prompt();
-	algo = *answer? atoi(answer): 1;
-	xfree(answer);
-	if( algo == 1 && !addmode ) {
-	    algo = 0;	/* create both keys */
-	    break;
+  if (!r_subkey_algo)
+    r_subkey_algo = &dummy_algo;
+  
+  tty_printf (_("Please select what kind of key you want:\n"));
+
+  if (!addmode)
+    tty_printf (_("   (%d) RSA and RSA (default)\n"), 1 );
+  if (!addmode)
+    tty_printf (_("   (%d) DSA and Elgamal\n"), 2 );
+
+  tty_printf (_("   (%d) DSA (sign only)\n"), 3 );
+  tty_printf (_("   (%d) RSA (sign only)\n"), 4 );
+
+  if (addmode)
+    {
+      tty_printf (_("   (%d) Elgamal (encrypt only)\n"), 5 );
+      tty_printf (_("   (%d) RSA (encrypt only)\n"), 6 );
+    }
+  if (opt.expert)
+    {
+      tty_printf (_("   (%d) DSA (set your own capabilities)\n"), 7 );
+      tty_printf (_("   (%d) RSA (set your own capabilities)\n"), 8 );
+    }
+  
+  for(;;)
+    {
+      *r_usage = 0;
+      *r_subkey_algo = 0;
+      answer = cpr_get ("keygen.algo", _("Your selection? "));
+      cpr_kill_prompt ();
+      algo = *answer? atoi (answer) : 1;
+      xfree(answer);
+      if (algo == 1 && !addmode)
+        {
+          algo = PUBKEY_ALGO_RSA;
+          *r_subkey_algo = PUBKEY_ALGO_RSA;
+          break;
 	}
-	else if( algo == 7 && opt.expert ) {
-	    algo = PUBKEY_ALGO_RSA;
-	    *r_usage=ask_key_flags(algo,addmode);
-	    break;
+      else if (algo == 2 && !addmode)
+        {
+          algo = PUBKEY_ALGO_DSA;
+          *r_subkey_algo = PUBKEY_ALGO_ELGAMAL_E;
+          break;
 	}
-	else if( algo == 6 && addmode ) {
-	    algo = PUBKEY_ALGO_RSA;
-            *r_usage = PUBKEY_USAGE_ENC;
-	    break;
+      else if (algo == 3)
+        {
+          algo = PUBKEY_ALGO_DSA;
+          *r_usage = PUBKEY_USAGE_SIG;
+          break;
 	}
-	else if( algo == 5 ) {
-	    algo = PUBKEY_ALGO_RSA;
-            *r_usage = PUBKEY_USAGE_SIG;
-	    break;
+      else if (algo == 4)
+        {
+          algo = PUBKEY_ALGO_RSA;
+          *r_usage = PUBKEY_USAGE_SIG;
+          break;
 	}
-	else if( algo == 4 && addmode ) {
-	    algo = PUBKEY_ALGO_ELGAMAL_E;
-            *r_usage = PUBKEY_USAGE_ENC;
-	    break;
+      else if (algo == 5 && addmode)
+        {
+          algo = PUBKEY_ALGO_ELGAMAL_E;
+          *r_usage = PUBKEY_USAGE_ENC;
+          break;
 	}
-	else if( algo == 3 && opt.expert ) {
-	    algo = PUBKEY_ALGO_DSA;
-	    *r_usage=ask_key_flags(algo,addmode);
-	    break;
+      else if (algo == 6 && addmode)
+        {
+          algo = PUBKEY_ALGO_RSA;
+          *r_usage = PUBKEY_USAGE_ENC;
+          break;
 	}
-	else if( algo == 2 ) {
-	    algo = PUBKEY_ALGO_DSA;
-            *r_usage = PUBKEY_USAGE_SIG;
-	    break;
+      else if (algo == 7 && opt.expert)
+        {
+          algo = PUBKEY_ALGO_DSA;
+          *r_usage = ask_key_flags (algo, addmode);
+          break;
 	}
-	else
-	    tty_printf(_("Invalid selection.\n"));
+      else if (algo == 8 && opt.expert)
+        {
+          algo = PUBKEY_ALGO_RSA;
+          *r_usage = ask_key_flags (algo, addmode);
+          break;
+	}
+      else
+        tty_printf (_("Invalid selection.\n"));
     }
-
-    return algo;
+  
+  return algo;
 }
 
 
+/* Ask for the key size.  ALGO is the algorithjm.  If PRIMARY_KEYSIZE
+   is not 0, the function asks for the size of the encryption
+   subkey. */
 static unsigned
-ask_keysize( int algo )
+ask_keysize (int algo, unsigned int primary_keysize)
 {
   unsigned int nbits, min, def=2048, max=4096;
+  int for_subkey = !!primary_keysize;
+  int autocomp = 0;
 
   if(opt.expert)
     min=512;
   else
     min=1024;
 
+  if (primary_keysize && !opt.expert)
+    {
+      /* Deduce the subkey size from the primary key size.  */
+      if (algo == PUBKEY_ALGO_DSA && primary_keysize > 3072)
+        nbits = 3072; /* For performance reasons we don't support more
+                         than 3072 bit DSA.  However we won't see this
+                         case anyway because DSA can't be used as an
+                         encryption subkey ;-). */
+      else
+        nbits = primary_keysize;
+      autocomp = 1;
+      goto leave;
+    }
+
   switch(algo)
     {
     case PUBKEY_ALGO_DSA:
       if(opt.flags.dsa2)
 	{
-	  def=1024;
+	  def=2048;
 	  max=3072;
 	}
       else
@@ -1743,18 +1790,16 @@ ask_keysize( int algo )
 
   for(;;)
     {
-      char *prompt,*answer;
-
-#define PROMPTSTRING _("What keysize do you want? (%u) ")
-
-      prompt=xmalloc(strlen(PROMPTSTRING)+20);
-      sprintf(prompt,PROMPTSTRING,def);
+      char *prompt, *answer;
 
-#undef PROMPTSTRING
-
-      answer = cpr_get("keygen.size",prompt);
-      cpr_kill_prompt();
-      nbits = *answer? atoi(answer): def;
+      if (for_subkey)
+        prompt = xasprintf (_("What keysize do you want "
+                              "for the subkey? (%u) "), def);
+      else
+        prompt = xasprintf (_("What keysize do you want? (%u) "), def);
+      answer = cpr_get ("keygen.size", prompt);
+      cpr_kill_prompt ();
+      nbits = *answer? atoi (answer): def;
       xfree(prompt);
       xfree(answer);
       
@@ -1767,15 +1812,18 @@ ask_keysize( int algo )
 
   tty_printf(_("Requested keysize is %u bits\n"), nbits );
 
+ leave:
   if( algo == PUBKEY_ALGO_DSA && (nbits % 64) )
     {
       nbits = ((nbits + 63) / 64) * 64;
-      tty_printf(_("rounded up to %u bits\n"), nbits );
+      if (!autocomp)
+        tty_printf(_("rounded up to %u bits\n"), nbits );
     }
   else if( (nbits % 32) )
     {
       nbits = ((nbits + 31) / 32) * 32;
-      tty_printf(_("rounded up to %u bits\n"), nbits );
+      if (!autocomp)
+        tty_printf(_("rounded up to %u bits\n"), nbits );
     }
 
   return nbits;
@@ -3003,16 +3051,19 @@ generate_keypair (const char *fname, const char *card_serialno,
     }
   else
     {
-      algo = ask_algo( 0, &use );
-      if( !algo )
-        { /* default: DSA with ElG subkey of the specified size */
+      int subkey_algo; 
+
+      algo = ask_algo (0, &subkey_algo, &use);
+      if (subkey_algo)
+        { 
+          /* Create primary and subkey at once.  */
           both = 1;
           r = xmalloc_clear( sizeof *r + 20 );
           r->key = pKEYTYPE;
-          sprintf( r->u.value, "%d", PUBKEY_ALGO_DSA );
+          sprintf( r->u.value, "%d", algo );
           r->next = para;
           para = r;
-	  nbits = ask_keysize( PUBKEY_ALGO_DSA );
+	  nbits = ask_keysize (algo, 0);
 	  r = xmalloc_clear( sizeof *r + 20 );
 	  r->key = pKEYLENGTH;
 	  sprintf( r->u.value, "%u", nbits);
@@ -3024,10 +3075,9 @@ generate_keypair (const char *fname, const char *card_serialno,
           r->next = para;
           para = r;
            
-          algo = PUBKEY_ALGO_ELGAMAL_E;
           r = xmalloc_clear( sizeof *r + 20 );
           r->key = pSUBKEYTYPE;
-          sprintf( r->u.value, "%d", algo );
+          sprintf( r->u.value, "%d", subkey_algo);
           r->next = para;
           para = r;
           r = xmalloc_clear( sizeof *r + 20 );
@@ -3055,10 +3105,10 @@ generate_keypair (const char *fname, const char *card_serialno,
               r->next = para;
               para = r;
             }
-           
+          nbits = 0;
         }
 
-      nbits = ask_keysize( algo );
+      nbits = ask_keysize (algo, nbits);
       r = xmalloc_clear( sizeof *r + 20 );
       r->key = both? pSUBKEYLENGTH : pKEYLENGTH;
       sprintf( r->u.value, "%u", nbits);
@@ -3658,9 +3708,9 @@ generate_subkeypair (KBNODE pub_keyblock, KBNODE sec_keyblock)
   if (rc)
     goto leave;
 
-  algo = ask_algo (1, &use);
+  algo = ask_algo (1, NULL, &use);
   assert (algo);
-  nbits = ask_keysize (algo);
+  nbits = ask_keysize (algo, 0);
   expire = ask_expire_interval (0, NULL);
   if (!cpr_enabled() && !cpr_get_answer_is_yes("keygen.sub.okay",
                                                _("Really create? (y/N) ")))
@@ -4017,8 +4067,8 @@ gen_card_key_with_backup (int algo, int keyno, int is_primary,
     mode_t oldmask;
 
     keyid_from_sk (sk, NULL);
-    sprintf (name_buffer,"sk_%08lX%08lX.gpg",
-             (ulong)sk->keyid[0], (ulong)sk->keyid[1]);
+    snprintf (name_buffer, sizeof name_buffer, "sk_%08lX%08lX.gpg",
+              (ulong)sk->keyid[0], (ulong)sk->keyid[1]);
 
     fname = make_filename (backup_dir, name_buffer, NULL);
     oldmask = umask (077);