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Code Activity

gpg: Allow adding of Additional Decryption Subkeys.

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* 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
This commit is contained in:
Werner Koch 2023-03-01 17:22:20 +01:00
parent 1aaadede76
commit 3a18378a92
No known key found for this signature in database
GPG key ID: E3FDFF218E45B72B
13 changed files with 278 additions and 76 deletions
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30
g10/sign.c
View file

@ -50,11 +50,6 @@
#endif
/* Bitflags to convey hints on what kind of signayire is created. */
#define SIGNHINT_KEYSIG 1
#define SIGNHINT_SELFSIG 2
/* Hack */
static int recipient_digest_algo;
@ -416,7 +411,10 @@ do_sign (ctrl_t ctrl, PKT_public_key *pksk, PKT_signature *sig,
byte *dp;
char *hexgrip;
if (pksk->timestamp > sig->timestamp )
/* An ADSK key commonly has a creation date older than the primary
* key. For example because the ADSK is used as an archive key for
* a group of users. */
if (pksk->timestamp > sig->timestamp && !(signhints & SIGNHINT_ADSK))
{
ulong d = pksk->timestamp - sig->timestamp;
log_info (ngettext("key %s was created %lu second"
@ -964,7 +962,7 @@ write_signature_packets (ctrl_t ctrl,
if (gcry_md_copy (&md, hash))
BUG ();
build_sig_subpkt_from_sig (sig, pk);
build_sig_subpkt_from_sig (sig, pk, 0);
mk_notation_policy_etc (ctrl, sig, NULL, pk);
if (opt.flags.include_key_block && IS_SIG (sig))
err = mk_sig_subpkt_key_block (ctrl, sig, pk);
@ -1758,14 +1756,14 @@ sign_symencrypt_file (ctrl_t ctrl, const char *fname, strlist_t locusr)
*
* SIGCLASS is the type of signature to create.
*
* DIGEST_ALGO is the digest algorithm. If it is 0 the function
* selects an appropriate one.
*
* TIMESTAMP is the timestamp to use for the signature. 0 means "now"
*
* DURATION is the amount of time (in seconds) until the signature
* expires.
*
* If CACHED_NONCE is not NULL the agent may use it to avoid
* additional pinnetry popups for the same keyblock.
*
* This function creates the following subpackets: issuer, created,
* and expire (if duration is not 0). Additional subpackets can be
* added using MKSUBPKT, which is called after these subpackets are
@ -1833,6 +1831,8 @@ make_keysig_packet (ctrl_t ctrl,
{
/* Hash the subkey binding/backsig/revocation. */
hash_public_key (md, subpk);
if ((subpk->pubkey_usage & PUBKEY_USAGE_RENC))
signhints |= SIGNHINT_ADSK;
}
else if (sigclass != 0x1F && sigclass != 0x20)
{
@ -1852,7 +1852,7 @@ make_keysig_packet (ctrl_t ctrl,
sig->expiredate = sig->timestamp + duration;
sig->sig_class = sigclass;
build_sig_subpkt_from_sig (sig, pksk);
build_sig_subpkt_from_sig (sig, pksk, signhints);
mk_notation_policy_etc (ctrl, sig, pk, pksk);
/* Crucial that the call to mksubpkt comes LAST before the calls
@ -1976,6 +1976,12 @@ update_keysig_packet (ctrl_t ctrl,
}
}
/* Detect an ADSK key binding signature. */
if ((sig->sig_class == 0x18
|| sig->sig_class == 0x19 || sig->sig_class == 0x28)
&& (pk->pubkey_usage & PUBKEY_USAGE_RENC))
signhints |= SIGNHINT_ADSK;
/* Note that already expired sigs will remain expired (with a
* duration of 1) since build-packet.c:build_sig_subpkt_from_sig
* detects this case. */
@ -1984,7 +1990,7 @@ update_keysig_packet (ctrl_t ctrl,
* automagically lower any sig expiration dates to correctly
* correspond to the differences in the timestamps (i.e. the
* duration will shrink). */
build_sig_subpkt_from_sig (sig, pksk);
build_sig_subpkt_from_sig (sig, pksk, signhints);
if (mksubpkt)
rc = (*mksubpkt)(sig, opaque);