gpg: Try Signer's User ID sub-packet with --auto-key-retrieve.

* g10/packet.h (PKT_signature): Add field 'signers_uid'.
* g10/parse-packet.c (parse_signature): Set this field.
* g10/free-packet.c (free_seckey_enc): Free field.
(copy_signature): Copy field.
* g10/mainproc.c (akl_has_wkd_method): New.
(check_sig_and_print): Extend NEWSIG status.  If WKD is enabled try to
locate a missing key via the signature's Signer's User ID sub-packet.
Do this right before trying a keyserver lookup.
--

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

1 files changed, 14 insertions, 0 deletions

diff --git a/g10/parse-packet.c b/g10/parse-packet.c
index c77e409e5..c30abcbe3 100644
--- a/g10/parse-packet.c
+++ b/g10/parse-packet.c
@@ -1915,6 +1915,20 @@ parse_signature (IOBUF inp, int pkttype, unsigned long pktlen,
       if (p)
 	sig->flags.pref_ks = 1;
 
+      p = parse_sig_subpkt (sig->hashed, SIGSUBPKT_SIGNERS_UID, &len);
+      if (p && len)
+        {
+          sig->signers_uid = xtrymalloc (len+1);
+          if (!sig->signers_uid)
+            {
+              rc = gpg_error_from_syserror ();
+              goto leave;
+            }
+          /* Note that we don't care about binary zeroes in the value.  */
+          memcpy (sig->signers_uid, p, len);
+          sig->signers_uid[len] = 0;
+        }
+
       p = parse_sig_subpkt (sig->hashed, SIGSUBPKT_NOTATION, NULL);
       if (p)
 	sig->flags.notation = 1;