gpg: Change the mode1003 format for composite keys.

* g10/export.c (secret_key_to_mode1003): Put both parts into one
container.
* g10/parse-packet.c (parse_key): Revert to old version.
--

Let's have a proper s-expression for composite keys.
Updates-commit: e5473262e88473a101241e7b4860882ebeb1ed97

3 files changed, 18 insertions, 25 deletions

diff --git a/doc/DETAILS b/doc/DETAILS
index cd6cf7314..588cb02c7 100644
--- a/doc/DETAILS
+++ b/doc/DETAILS
@@ -1576,15 +1576,16 @@ CREATE TABLE signatures (
          - The serial number. Regardless of what the length octet
            indicates no more than 16 octets are stored.
   - 3 :: The internal representation of a private key: For v4 keys we
-         first write 4 octets big endian length of the following
-         s-expression(s) with the protected or unprotected private key;
-         for v5 keys this is not necessarily because that length
-         header is always there.  The actual data are N octets of
-         s-expression.  Any protection (including the real S2K) is
-         part of that data.  For a dual key the second s-expression is
-         concatenated to the first; thus two complete s-expressions
-         are used.  Note that the public key parameters are
-         repeated in the s-expression.
+    first write 4 octets big endian length of the following
+    s-expression(s) with the protected or unprotected private key; for
+    v5 keys this is not necessarily because that length header is
+    always there.  The actual data are N octets of s-expression.  Any
+    protection (including the real S2K) is part of that data.  For a
+    composite key (aka PQ/T hybrid) the two s-expressions are combined
+    in a new s-expression using this layout:
+       (composite-key(<ecckey>)(<kyberkey>)).
+    Note that the respective public key parameters are repeated in the
+    s-expressions.
 
   Note that gpg internally stores the GNU S2K Extension Number as an
   S2K Specifier with an offset of 1000.
diff --git a/g10/export.c b/g10/export.c
index 7c7869fb8..fc2625684 100644
--- a/g10/export.c
+++ b/g10/export.c
@@ -837,6 +837,8 @@ secret_key_to_mode1003 (gcry_sexp_t s_key, PKT_public_key *pk, int is_part2)
         goto leave;
       if (is_part2)  /* Append secret s-expr to the existing one.  */
         {
+          char const prefix[] = "(13:composite-key";
+          unsigned int prefixlen = strlen (prefix);
           const unsigned char *oldbuf;
           unsigned int oldbuflen;
           unsigned char *newbuf;
@@ -845,16 +847,18 @@ secret_key_to_mode1003 (gcry_sexp_t s_key, PKT_public_key *pk, int is_part2)
                       gcry_mpi_get_flag (pk->pkey[npkey], GCRYMPI_FLAG_OPAQUE));
           oldbuf = gcry_mpi_get_opaque (pk->pkey[npkey], &oldbuflen);
           oldbuflen = (oldbuflen +7)/8;  /* Fixup bits to bytes */
-          newbuf = xtrymalloc_secure (oldbuflen + buflen);
+          newbuf = xtrymalloc_secure (prefixlen + oldbuflen + buflen + 1);
           if (!newbuf)
             {
               err = gpg_error_from_syserror ();
               goto leave;
             }
-          memcpy (newbuf, oldbuf, oldbuflen);
-          memcpy (newbuf+oldbuflen, buf, buflen);
+          memcpy (newbuf, prefix, prefixlen);
+          memcpy (newbuf+prefixlen, oldbuf, oldbuflen);
+          memcpy (newbuf+prefixlen+oldbuflen, buf, buflen);
+          newbuf[prefixlen+oldbuflen+buflen] = ')'; /* close prefix */
           buf = newbuf;
-          buflen = oldbuflen + buflen;
+          buflen = prefixlen + oldbuflen + buflen + 1;
         }
       /* Note that BUF is consumed by gcry_mpi_set_opaque.  */
       pk->pkey[npkey] = gcry_mpi_set_opaque (NULL, buf, buflen*8);
diff --git a/g10/parse-packet.c b/g10/parse-packet.c
index aac3a988c..22db04291 100644
--- a/g10/parse-packet.c
+++ b/g10/parse-packet.c
@@ -3079,22 +3079,10 @@ 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