gpg: New commands --add-recipients and --change-recipients.

* g10/gpg.c (aAddRecipients, aChangeRecipients): New consts.
(opts): Add --add-recipients and --change-recipients.
(main): Handle them.
* g10/gpg.h (struct server_control_s): Add fields modify_recipients,
clear_recipients, and last_read_ctb.
* g10/armor.c (was_armored): New.
* g10/decrypt.c (decrypt_message): Add optional arg 'remusr'.  Handle
re-encryption if desired.
* g10/encrypt.c (write_pubkey_enc): Factor info printing out to ...
(show_encrypted_for_user_info): new.
(reencrypt_to_new_recipients): New.
* g10/packet.h (struct parse_packet_ctx_s): Add fields only_fookey_enc
and last_ctb.
(init_parse_packet): Clear them.
* g10/parse-packet.c (parse): Store CTB in the context.  Early return
on pubkey_enc and symkey_enc packets if requested.
* g10/mainproc.c (proc_encrypted): Allow for PKT being NULL.  Return
early in modify-recipients mode.
(proc_encryption_packets): Add two optional args 'r_dek' and 'r_list'.
Adjust callers.  Call do_proc_packets in modify-recipients mode
depending on the optional args.
(do_proc_packets): Add arg 'keep_dek_and_list'.  Adjust callers.  Save
the last read CTB in CTRL and return after the last fooenc_enc
packets.
--

This basically works but does not yet handle symmetric encrypted
packets (symkey_enc).

GnuPG-bug-id: 1825
(Yes, this is an at least 9 year old feature request)

1 files changed, 7 insertions, 1 deletions

diff --git a/g10/main.h b/g10/main.h
index 1c93c96e6..546a0b5b8 100644
--- a/g10/main.h
+++ b/g10/main.h
@@ -248,6 +248,11 @@ int encrypt_crypt (ctrl_t ctrl, gnupg_fd_t filefd, const char *filename,
                    gnupg_fd_t outputfd);
 void encrypt_crypt_files (ctrl_t ctrl,
                           int nfiles, char **files, strlist_t remusr);
+gpg_error_t reencrypt_to_new_recipients (ctrl_t ctrl, int armor,
+                                         const char *filename, iobuf_t infp,
+                                         strlist_t recipients,
+                                         DEK *dek,
+                                         struct pubkey_enc_list *pkenc_list);
 int encrypt_filter (void *opaque, int control,
 		    iobuf_t a, byte *buf, size_t *ret_len);
 
@@ -501,7 +506,8 @@ void check_assert_signer_list (const char *mainpkhex, const char *pkhex);
 void check_assert_pubkey_algo (const char *algostr, const char *pkhex);
 
 /*-- decrypt.c --*/
-int decrypt_message (ctrl_t ctrl, const char *filename );
+gpg_error_t decrypt_message (ctrl_t ctrl, const char *filename,
+                             strlist_t remusr);
 gpg_error_t decrypt_message_fd (ctrl_t ctrl, gnupg_fd_t input_fd,
                                 gnupg_fd_t output_fd);
 void decrypt_messages (ctrl_t ctrl, int nfiles, char *files[]);