Implement unattended OpenPGP secret key import.

* agent/command.c (cmd_import_key): Add option --unattended.
* agent/cvt-openpgp.c (convert_transfer_key): New.
(do_unprotect): Factor some code out to ...
(prepare_unprotect): new function.
(convert_from_openpgp): Factor all code out to ...
(convert_from_openpgp_main): this.  Add arg 'passphrase'.  Implement
openpgp-native protection modes.
(convert_from_openpgp_native): New.
* agent/t-protect.c (convert_from_openpgp_native): New dummy fucntion
* agent/protect-tool.c (convert_from_openpgp_native): Ditto.
* agent/protect.c (agent_unprotect): Add arg CTRL.  Adjust all
callers.  Support openpgp-native protection.
* g10/call-agent.c (agent_import_key): Add arg 'unattended'.
* g10/import.c (transfer_secret_keys): Use unattended in batch mode.
--

With the gpg-agent taking care of the secret keys, the user needs to
migrate existing keys from secring.gpg to the agent.  This and also
the standard import of secret keys required the user to unprotect the
secret keys first, so that gpg-agent was able to re-protected them
using its own scheme.  With many secret keys this is quite some
usability hurdle.  In particular if a passphrase is not instantly
available.

To make this migration smoother, this patch implements an unattended
key import/migration which delays the conversion to the gpg-agent
format until the key is actually used.  For example:

   gpg2 --batch --import mysecretkey.gpg

works without any user interaction due to the use of --batch.  Now if
a key is used (e.g. "gpg2 -su USERID_FROM_MYSECRETKEY foo"), gpg-agent
has to ask for the passphrase anyway, converts the key from the
openpgp format to the internal format, signs, re-encrypts the key and
tries to store it in the gpg-agent format to the disk.  The next time,
the internal format of the key is used.

This patch has only been tested with the old demo keys, more tests
with other protection formats and no protection are needed.

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

1 files changed, 6 insertions, 3 deletions

diff --git a/agent/findkey.c b/agent/findkey.c
index ebdcc038e..d11f0888a 100644
--- a/agent/findkey.c
+++ b/agent/findkey.c
@@ -66,6 +66,9 @@ agent_write_private_key (const unsigned char *grip,
 
   fname = make_filename (opt.homedir, GNUPG_PRIVATE_KEYS_DIR, hexgrip, NULL);
 
+  /* FIXME: Write to a temp file first so that write failures during
+     key updates won't lead to a key loss.  */
+
   if (!force && !access (fname, F_OK))
     {
       log_error ("secret key file '%s' already exists\n", fname);
@@ -119,7 +122,7 @@ try_unprotect_cb (struct pin_entry_info_s *pi)
   assert (!arg->unprotected_key);
 
   arg->change_required = 0;
-  err = agent_unprotect (arg->protected_key, pi->pin, protected_at,
+  err = agent_unprotect (arg->ctrl, arg->protected_key, pi->pin, protected_at,
                          &arg->unprotected_key, &dummy);
   if (err)
     return err;
@@ -325,7 +328,7 @@ unprotect (ctrl_t ctrl, const char *cache_nonce, const char *desc_text,
       pw = agent_get_cache (cache_nonce, CACHE_MODE_NONCE);
       if (pw)
         {
-          rc = agent_unprotect (*keybuf, pw, NULL, &result, &resultlen);
+          rc = agent_unprotect (ctrl, *keybuf, pw, NULL, &result, &resultlen);
           if (!rc)
             {
               if (r_passphrase)
@@ -350,7 +353,7 @@ unprotect (ctrl_t ctrl, const char *cache_nonce, const char *desc_text,
       pw = agent_get_cache (hexgrip, cache_mode);
       if (pw)
         {
-          rc = agent_unprotect (*keybuf, pw, NULL, &result, &resultlen);
+          rc = agent_unprotect (ctrl, *keybuf, pw, NULL, &result, &resultlen);
           if (!rc)
             {
               if (r_passphrase)