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, 4 insertions, 3 deletions

diff --git a/g10/getkey.c b/g10/getkey.c
index 093ce61b0..3e94875b2 100644
--- a/g10/getkey.c
+++ b/g10/getkey.c
@@ -1809,12 +1809,12 @@ get_pubkey_from_buffer (ctrl_t ctrl, PKT_public_key *pkbuf,
  * returned public key may be a subkey rather than the primary key.
  * Note: The self-signed data has already been merged into the public
  * key using merge_selfsigs.  Free *PK by calling
- * release_public_key_parts (or, if PK was allocated using xfree, you
+ * release_public_key_parts (or, if PK was allocated using xmalloc, you
  * can use free_public_key, which calls release_public_key_parts(PK)
  * and then xfree(PK)).
  *
  * If PK->REQ_USAGE is set, it is used to filter the search results.
- * (Thus, if PK is not NULL, PK->REQ_USAGE must be valid!!!)  See the
+ * Thus, if PK is not NULL, PK->REQ_USAGE must be valid!  See the
  * documentation for finish_lookup to understand exactly how this is
  * used.
  *
@@ -2417,7 +2417,8 @@ merge_keys_and_selfsig (ctrl_t ctrl, kbnode_t keyblock)
 }
 
 
-static int
+/* This function parses the key flags and returns PUBKEY_USAGE_ flags.  */
+unsigned int
 parse_key_usage (PKT_signature * sig)
 {
   int key_usage = 0;