gpg: Fix key generation with only an email part.

* g10/keygen.c (proc_parameter_file): Special case the email only
case.
--

Using a parameter file like

  %ask-passphrase
  key-type:      RSA
  key-length:    2048
  key-usage:     sign
  subkey-type:   RSA
  subkey-length: 2048
  subkey-usage:  encrypt
  name-email:    [email protected]

with "gpg --gen-key --patch" the result was this key

  pub   rsa2048 2017-09-11 [SC]
        63A8C1BA12CC289A0E8072C971C7F8D4A18CE0BE
  uid           [ultimate]  <[email protected]>
  sub   rsa2048 2017-09-11 [E]

At least the the extra leading space the left angle bracket is wrong.
Further some mail providers reject keys which consist of more than
just a plain mail address.  Using just a mail address is anyway the
new new suggested content for a user id.  With this patch the key
will be

  pub   rsa2048 2017-09-11 [SC]
        B302343C20EA6DECDB6A155135352F2520397080
  uid           [ultimate] [email protected]
  sub   rsa2048 2017-09-11 [E]

Signed-off-by: Werner Koch <[email protected]>

1 files changed, 8 insertions, 1 deletions

diff --git a/g10/keygen.c b/g10/keygen.c
index 6a3d32345..08bc62131 100644
--- a/g10/keygen.c
+++ b/g10/keygen.c
@@ -3530,7 +3530,14 @@ proc_parameter_file (ctrl_t ctrl, struct para_data_s *para, const char *fname,
 	  if( s2 )
 	    p = stpcpy(stpcpy(stpcpy(p," ("), s2 ),")");
 	  if( s3 )
-	    p = stpcpy(stpcpy(stpcpy(p," <"), s3 ),">");
+            {
+              /* If we have only the email part, do not add the space
+               * and the angle brackets.  */
+              if (*p)
+                p = stpcpy(stpcpy(stpcpy(p," <"), s3 ),">");
+              else
+                p = stpcpy (p, s3);
+            }
           append_to_parameter (para, r);
 	  have_user_id=1;
 	}