gpg: Allow the export of Kyber secret keys.

* g10/export.c (match_curve_skey_pk): Allow the ECC part of a Kyber
key.
(secret_key_to_mode1003): Add arg is_part2.  Add code to allow a
second call to merge the Kyber part to the secret key s-exp.
(receive_seckey_from_agent): Add arg is_part2 and forward it.
(do_export_one_keyblock): Detect a dual key and handle it accordingly.
* g10/parse-packet.c (parse_key): In the secret key list code also
print the second s-expr of a dual key.
--

GnuPG-bug-id: 7315

1 files changed, 13 insertions, 0 deletions

diff --git a/g10/parse-packet.c b/g10/parse-packet.c
index baac7c649..aac3a988c 100644
--- a/g10/parse-packet.c
+++ b/g10/parse-packet.c
@@ -3079,9 +3079,22 @@ parse_key (IOBUF inp, int pkttype, unsigned long pktlen,
               if (mpi_print_mode)
                 {
                   char *tmpsxp = canon_sexp_to_string (tmpp, pktlen);
+                  size_t len1 = gcry_sexp_canon_len (tmpp, pktlen, NULL, NULL);
+                  const char *tp = tmpp;
+
                   es_fprintf (listfp, "\tskey[%d]: %s\n", npkey,
                               tmpsxp? trim_trailing_spaces (tmpsxp)
                               /*  */: "[invalid S-expression]");
+                  if (len1 && len1 < pktlen
+                      && tp[len1] == '(' && tp[pktlen-1] == ')' )
+                    {
+                      /* Second s-expression from a dual key.  */
+                      xfree (tmpsxp);
+                      tmpsxp = canon_sexp_to_string (tp+len1, pktlen-len1);
+                      es_fprintf (listfp, "\t part-2: %s\n",
+                                  tmpsxp? trim_trailing_spaces (tmpsxp)
+                                  /*  */: "[invalid S-expression]");
+                    }
                   xfree (tmpsxp);
                 }
               else