gpg: Allow adding of Additional Decryption Subkeys.

* g10/free-packet.c (copy_public_key): Factor some code out to ...
(copy_public_key_basics): new.
* g10/build-packet.c (build_sig_subpkt_from_sig): New arg signhints.
* g10/packet.h (PUBKEY_USAGE_RENC): Fix value.
(SIGNHINT_KEYSIG, SIGNHINT_SELFSIG): Moved from sign.c.
(SIGNHINT_ADSK): New.
(PKT_public_key): Change pubkey_usage from byte to u16.
(PKT_user_id): Cosmetic fix: change help_key_usage from int to u16.
* g10/getkey.c (parse_key_usage): Make public.
* g10/misc.c (openpgp_pk_algo_usage): Take PUBKEY_USAGE_RENC in
account.
* g10/sign.c (update_keysig_packet): Set SIGNHINT_ADSK.
(make_keysig_packet): Ditto.
(do_sign): No time warp check in ADSK mode.
* g10/sig-check.c (check_signature_metadata_validity): Ditto.
* g10/keygen.c (struct opaque_data_usage_and_pk): Remove.
(write_keybinding): Do not use the removed struct.
(do_add_key_flags): Support PUBKEY_USAGE_RENC and others.
(keygen_add_key_flags_and_expire): Rewrite and make public.
* g10/keyedit.c (enum cmdids): Add cmdADDADSK.
(keyedit_menu): Add command "addadsk".
(menu_addadsk): New.
--

This makes use of a new encryption flag:

  The "restricted encryption key" (2nd,0x04) does not take part in any
  automatic selection of encryption keys.  It is only found on a
  subkey signature (type 0x18), one that refers to the key the flag
  applies to.

Followup patches will add encryption support and a --quick command.

GnuPG-bug-id: 6395

1 files changed, 23 insertions, 7 deletions

diff --git a/g10/free-packet.c b/g10/free-packet.c
index 243cc7518..b0642043e 100644
--- a/g10/free-packet.c
+++ b/g10/free-packet.c
@@ -211,10 +211,10 @@ copy_prefs (const prefitem_t *prefs)
 
 
 /* Copy the public key S to D.  If D is NULL allocate a new public key
-   structure.  If S has seckret key infos, only the public stuff is
-   copied.  */
+ * structure.  Only the basic stuff is copied; not any ancillary
+ * data.  */
 PKT_public_key *
-copy_public_key (PKT_public_key *d, PKT_public_key *s)
+copy_public_key_basics (PKT_public_key *d, PKT_public_key *s)
 {
   int n, i;
 
@@ -222,8 +222,8 @@ copy_public_key (PKT_public_key *d, PKT_public_key *s)
     d = xmalloc (sizeof *d);
   memcpy (d, s, sizeof *d);
   d->seckey_info = NULL;
-  d->user_id = scopy_user_id (s->user_id);
-  d->prefs = copy_prefs (s->prefs);
+  d->user_id = NULL;
+  d->prefs = NULL;
 
   n = pubkey_get_npkey (s->pubkey_algo);
   i = 0;
@@ -237,6 +237,24 @@ copy_public_key (PKT_public_key *d, PKT_public_key *s)
   for (; i < PUBKEY_MAX_NSKEY; i++)
     d->pkey[i] = NULL;
 
+  d->revkey = NULL;
+  d->serialno = NULL;
+  d->updateurl = NULL;
+
+  return d;
+}
+
+
+/* Copy the public key S to D.  If D is NULL allocate a new public key
+   structure.  If S has seckret key infos, only the public stuff is
+   copied.  */
+PKT_public_key *
+copy_public_key (PKT_public_key *d, PKT_public_key *s)
+{
+  d = copy_public_key_basics (d, s);
+  d->user_id = scopy_user_id (s->user_id);
+  d->prefs = copy_prefs (s->prefs);
+
   if (!s->revkey && s->numrevkeys)
     BUG();
   if (s->numrevkeys)
@@ -244,8 +262,6 @@ copy_public_key (PKT_public_key *d, PKT_public_key *s)
       d->revkey = xmalloc(sizeof(struct revocation_key)*s->numrevkeys);
       memcpy(d->revkey,s->revkey,sizeof(struct revocation_key)*s->numrevkeys);
     }
-  else
-    d->revkey = NULL;
 
   if (s->serialno)
     d->serialno = xstrdup (s->serialno);