core: New flags GPGME_DECRYPT_UNWRAP and GPGME_ENCRYPT_WRAP.

* src/gpgme.h.in (GPGME_ENCRYPT_WRAP): New const.
(gpgme_decrypt_flags_t): New enum.
(GPGME_DECRYPT_VERIFY): New const
(GPGME_DECRYPT_UNWRAP): New const
(gpgme_op_decrypt_ext_start): New func.
(gpgme_op_decrypt_ext): New func.
* src/decrypt-verify.c (gpgme_op_decrypt_ext_start): New.
(gpgme_op_decrypt_ext): New.
(decrypt_verify_start): Add arg FLAGS.  Replace call to
engine_op_decrypt_verify by the plain decrypt with the flag set.
(gpgme_op_decrypt_verify_start): Pass the flag.
(gpgme_op_decrypt_verify): Pass the flag.
* src/decrypt.c (decrypt_start): Rename to ...
(_gpgme_decrypt_start): this.  Add arg FLAGS.  Pass FLAGS to
engine_op_decrypt.
(gpgme_op_decrypt_start): Adjust for chnage pass 0 for FLAG.
(gpgme_op_decrypt_start): Ditto.
* src/engine.c (_gpgme_engine_op_decrypt_verify): Remove.
(_gpgme_engine_op_decrypt): Add arg FLAGS.
* src/gpgme.def, src/libgpgme.vers: Add new functions.
* src/engine-backend.h (struct engine_ops): Remove member
'decrypt_verify'.  Add FLAGS to 'decrypt'.  Adjust all initialization.
* src/engine-uiserver.c (uiserver_decrypt): Remove.
(uiserver_decrypt_verify): Remove.
(_uiserver_decrypt): Rename to ...
(uiserver_decrypt): this.  Replace arg VERIFY by new arg FLAGS.
* src/engine-gpg.c (gpg_decrypt): Support GPGME_DECRYPT_UNWRAP.
(gpg_encrypt): Support GPGME_ENCRYPT_WRAP.

* tests/run-decrypt.c (main): New option --unwrap.
* tests/run-encrypt.c (main): New option --wrap.
--

Manual testing of that wrap/unwrap feature can be done this way:

 ./run-encrypt --verbose --key Alice /etc/motd > x
 ./run-decrypt --verbose --unwrap x > y
 ./run-encrypt --verbose --key Bob --wrap y > z

1. The message was first encrypted to Alice.
2. Alice decrypts the message receiving a valid OpenPGP message.
3. Alice encrypt that message to Bob

This will also work with encrypted and signed messages; the signature
will be kept intact during re-encryption.  Requires GnuPG 2.1.12.

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

1 files changed, 12 insertions, 6 deletions

diff --git a/src/decrypt.c b/src/decrypt.c
index 43717c0d..f30f80f6 100644
--- a/src/decrypt.c
+++ b/src/decrypt.c
@@ -25,6 +25,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
+#include <assert.h>
 
 #include "debug.h"
 #include "gpgme.h"
@@ -358,12 +359,15 @@ _gpgme_op_decrypt_init_result (gpgme_ctx_t ctx)
 }
 
 
-static gpgme_error_t
-decrypt_start (gpgme_ctx_t ctx, int synchronous,
-               gpgme_data_t cipher, gpgme_data_t plain)
+gpgme_error_t
+_gpgme_decrypt_start (gpgme_ctx_t ctx, int synchronous,
+                      gpgme_decrypt_flags_t flags,
+                      gpgme_data_t cipher, gpgme_data_t plain)
 {
   gpgme_error_t err;
 
+  assert (!(flags & GPGME_DECRYPT_VERIFY));
+
   err = _gpgme_op_reset (ctx, synchronous);
   if (err)
     return err;
@@ -390,7 +394,9 @@ decrypt_start (gpgme_ctx_t ctx, int synchronous,
 
   _gpgme_engine_set_status_handler (ctx->engine, decrypt_status_handler, ctx);
 
-  return _gpgme_engine_op_decrypt (ctx->engine, cipher, plain,
+  return _gpgme_engine_op_decrypt (ctx->engine,
+                                   flags,
+                                   cipher, plain,
                                    ctx->export_session_keys,
                                    ctx->override_session_key);
 }
@@ -408,7 +414,7 @@ gpgme_op_decrypt_start (gpgme_ctx_t ctx, gpgme_data_t cipher,
   if (!ctx)
     return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));
 
-  err = decrypt_start (ctx, 0, cipher, plain);
+  err = _gpgme_decrypt_start (ctx, 0, 0, cipher, plain);
   return TRACE_ERR (err);
 }
 
@@ -426,7 +432,7 @@ gpgme_op_decrypt (gpgme_ctx_t ctx, gpgme_data_t cipher, gpgme_data_t plain)
   if (!ctx)
     return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));
 
-  err = decrypt_start (ctx, 1, cipher, plain);
+  err = _gpgme_decrypt_start (ctx, 1, 0, cipher, plain);
   if (!err)
     err = _gpgme_wait_one (ctx);
   return TRACE_ERR (err);