core: Implement context flag "override-session-key".

* src/gpgme.c (gpgme_set_ctx_flag): Add flags "export-session-key" and
"override-session-key".
(gpgme_get_ctx_flag): Ditto.
(gpgme_set_export_session_keys): Remove.
(gpgme_get_export_session_keys): Remove.
* src/gpgme.def, src/libgpgme.vers: Remove them.
* src/context.h (struct gpgme_context): Add field
override_session_key.
* src/decrypt-verify.c (decrypt_verify_start): Pass
override_session_key value to the engine.
* src/decrypt.c (decrypt_start): Ditto.
* src/engine.c (_gpgme_engine_op_decrypt): Ditto.
(_gpgme_engine_op_decrypt_verify): Ditto.
* src/engine-backend.h (struct engine_ops): Extend DECRYPT and
DECRYPT_VERIFY_START with override_session_key.
* src/engine-uiserver.c (_uiserver_decrypt): Add stub arg
override_session_key.
(uiserver_decrypt): Ditto.
(uiserver_decrypt_verify): Ditto.
* src/engine-gpgsm.c (gpgsm_decrypt): Ditto.
* src/engine-gpg.c (gpg_decrypt): Add arg override_session_key and set
corresponding gpg option.

* tests/run-decrypt.c (print_result): Print the session key if
available.
(main): Add options --export-session-key and --override-session-key.

--

To keep the number of context manipulation functions at bay, this
patches removes the just added gpgme_set_export_session_keys and
gpgme_get_export_session_keys by flags for the generic context
function.

The patch also implements the --override-session-key feature.

GnuPG-bug-id: 2754
Signed-off-by: Werner Koch <[email protected]>

13 files changed, 76 insertions, 56 deletions

diff --git a/src/context.h b/src/context.h
index 94935c80..d915b994 100644
--- a/src/context.h
+++ b/src/context.h
@@ -135,6 +135,9 @@ struct gpgme_context
   /* The sender's addr-spec or NULL.  */
   char *sender;
 
+  /* The gpg specific override session key or NULL. */
+  char *override_session_key;
+
   /* The locale for the pinentry.  */
   char *lc_ctype;
   char *lc_messages;
diff --git a/src/decrypt-verify.c b/src/decrypt-verify.c
index 00d256a9..e0aa8ea9 100644
--- a/src/decrypt-verify.c
+++ b/src/decrypt-verify.c
@@ -77,7 +77,9 @@ decrypt_verify_start (gpgme_ctx_t ctx, int synchronous,
   _gpgme_engine_set_status_handler (ctx->engine,
 				    decrypt_verify_status_handler, ctx);
 
-  return _gpgme_engine_op_decrypt_verify (ctx->engine, cipher, plain, ctx->export_session_keys);
+  return _gpgme_engine_op_decrypt_verify (ctx->engine, cipher, plain,
+                                          ctx->export_session_keys,
+                                          ctx->override_session_key);
 }
 
 
diff --git a/src/decrypt.c b/src/decrypt.c
index 49c735ca..43717c0d 100644
--- a/src/decrypt.c
+++ b/src/decrypt.c
@@ -360,7 +360,7 @@ _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_data_t cipher, gpgme_data_t plain)
 {
   gpgme_error_t err;
 
@@ -390,7 +390,9 @@ 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, ctx->export_session_keys);
+  return _gpgme_engine_op_decrypt (ctx->engine, cipher, plain,
+                                   ctx->export_session_keys,
+                                   ctx->override_session_key);
 }
 
 
diff --git a/src/engine-backend.h b/src/engine-backend.h
index 144b1561..cfc624d4 100644
--- a/src/engine-backend.h
+++ b/src/engine-backend.h
@@ -62,9 +62,11 @@ struct engine_ops
   gpgme_error_t (*set_locale) (void *engine, int category, const char *value);
   gpgme_error_t (*set_protocol) (void *engine, gpgme_protocol_t protocol);
   gpgme_error_t (*decrypt) (void *engine, gpgme_data_t ciph,
-			    gpgme_data_t plain, int export_session_key);
+			    gpgme_data_t plain, int export_session_key,
+                            const char *override_session_key);
   gpgme_error_t (*decrypt_verify) (void *engine, gpgme_data_t ciph,
-				   gpgme_data_t plain, int export_session_key);
+				   gpgme_data_t plain, int export_session_key,
+                                   const char *override_session_key);
   gpgme_error_t (*delete) (void *engine, gpgme_key_t key, int allow_secret);
   gpgme_error_t (*edit) (void *engine, int type, gpgme_key_t key,
 			 gpgme_data_t out, gpgme_ctx_t ctx /* FIXME */);
diff --git a/src/engine-gpg.c b/src/engine-gpg.c
index 0e43c248..21ed5bc3 100644
--- a/src/engine-gpg.c
+++ b/src/engine-gpg.c
@@ -1550,7 +1550,8 @@ add_input_size_hint (engine_gpg_t gpg, gpgme_data_t data)
 
 
 static gpgme_error_t
-gpg_decrypt (void *engine, gpgme_data_t ciph, gpgme_data_t plain, int export_session_key)
+gpg_decrypt (void *engine, gpgme_data_t ciph, gpgme_data_t plain,
+             int export_session_key, const char *override_session_key)
 {
   engine_gpg_t gpg = engine;
   gpgme_error_t err;
@@ -1560,6 +1561,13 @@ gpg_decrypt (void *engine, gpgme_data_t ciph, gpgme_data_t plain, int export_ses
   if (!err && export_session_key)
     err = add_arg (gpg, "--show-session-key");
 
+  if (!err && override_session_key && *override_session_key)
+    {
+      err = add_arg (gpg, "--override-session-key");
+      if (!err)
+        err = add_arg (gpg, override_session_key);
+    }
+
   /* Tell the gpg object about the data.  */
   if (!err)
     err = add_arg (gpg, "--output");
diff --git a/src/engine-gpgsm.c b/src/engine-gpgsm.c
index 2ff353b9..d1be049e 100644
--- a/src/engine-gpgsm.c
+++ b/src/engine-gpgsm.c
@@ -1120,13 +1120,16 @@ gpgsm_reset (void *engine)
 
 
 static gpgme_error_t
-gpgsm_decrypt (void *engine, gpgme_data_t ciph, gpgme_data_t plain, int export_session_key)
+gpgsm_decrypt (void *engine, gpgme_data_t ciph, gpgme_data_t plain,
+               int export_session_key, const char *override_session_key)
 {
   engine_gpgsm_t gpgsm = engine;
   gpgme_error_t err;
+
   /* gpgsm is not capable of exporting session keys right now, so we
    * will ignore this if requested. */
   (void)export_session_key;
+  (void)override_session_key;
 
   if (!gpgsm)
     return gpg_error (GPG_ERR_INV_VALUE);
diff --git a/src/engine-uiserver.c b/src/engine-uiserver.c
index 26f0d18b..ee7b1d2d 100644
--- a/src/engine-uiserver.c
+++ b/src/engine-uiserver.c
@@ -961,13 +961,16 @@ uiserver_reset (void *engine)
 static gpgme_error_t
 _uiserver_decrypt (void *engine, int verify,
 		   gpgme_data_t ciph, gpgme_data_t plain,
-                   int export_session_key)
+                   int export_session_key, const char *override_session_key)
 {
   engine_uiserver_t uiserver = engine;
   gpgme_error_t err;
   const char *protocol;
   char *cmd;
 
+  (void)override_session_key; /* Fixme: We need to see now to add this
+                               * to the UI server protocol  */
+
   if (!uiserver)
     return gpg_error (GPG_ERR_INV_VALUE);
   if (uiserver->protocol == GPGME_PROTOCOL_DEFAULT)
@@ -1008,16 +1011,21 @@ _uiserver_decrypt (void *engine, int verify,
 
 
 static gpgme_error_t
-uiserver_decrypt (void *engine, gpgme_data_t ciph, gpgme_data_t plain, int export_session_key)
+uiserver_decrypt (void *engine, gpgme_data_t ciph, gpgme_data_t plain,
+                  int export_session_key, const char *override_session_key)
 {
-  return _uiserver_decrypt (engine, 0, ciph, plain, export_session_key);
+  return _uiserver_decrypt (engine, 0, ciph, plain,
+                            export_session_key, override_session_key);
 }
 
 
 static gpgme_error_t
-uiserver_decrypt_verify (void *engine, gpgme_data_t ciph, gpgme_data_t plain, int export_session_key)
+uiserver_decrypt_verify (void *engine, gpgme_data_t ciph, gpgme_data_t plain,
+                         int export_session_key,
+                         const char *override_session_key)
 {
-  return _uiserver_decrypt (engine, 1, ciph, plain, export_session_key);
+  return _uiserver_decrypt (engine, 1, ciph, plain,
+                            export_session_key, override_session_key);
 }
 
 
diff --git a/src/engine.c b/src/engine.c
index b43f683e..d542b25c 100644
--- a/src/engine.c
+++ b/src/engine.c
@@ -653,7 +653,8 @@ _gpgme_engine_set_protocol (engine_t engine, gpgme_protocol_t protocol)
 
 gpgme_error_t
 _gpgme_engine_op_decrypt (engine_t engine, gpgme_data_t ciph,
-			  gpgme_data_t plain, int export_session_key)
+			  gpgme_data_t plain, int export_session_key,
+                          const char *override_session_key)
 {
   if (!engine)
     return gpg_error (GPG_ERR_INV_VALUE);
@@ -661,13 +662,15 @@ _gpgme_engine_op_decrypt (engine_t engine, gpgme_data_t ciph,
   if (!engine->ops->decrypt)
     return gpg_error (GPG_ERR_NOT_IMPLEMENTED);
 
-  return (*engine->ops->decrypt) (engine->engine, ciph, plain, export_session_key);
+  return (*engine->ops->decrypt) (engine->engine, ciph, plain,
+                                  export_session_key, override_session_key);
 }
 
 
 gpgme_error_t
 _gpgme_engine_op_decrypt_verify (engine_t engine, gpgme_data_t ciph,
-				 gpgme_data_t plain, int export_session_key)
+				 gpgme_data_t plain, int export_session_key,
+                                 const char *override_session_key)
 {
   if (!engine)
     return gpg_error (GPG_ERR_INV_VALUE);
@@ -675,7 +678,9 @@ _gpgme_engine_op_decrypt_verify (engine_t engine, gpgme_data_t ciph,
   if (!engine->ops->decrypt_verify)
     return gpg_error (GPG_ERR_NOT_IMPLEMENTED);
 
-  return (*engine->ops->decrypt_verify) (engine->engine, ciph, plain, export_session_key);
+  return (*engine->ops->decrypt_verify) (engine->engine, ciph, plain,
+                                         export_session_key,
+                                         override_session_key);
 }
 
 
diff --git a/src/engine.h b/src/engine.h
index 512ac19a..29d2f259 100644
--- a/src/engine.h
+++ b/src/engine.h
@@ -84,11 +84,14 @@ _gpgme_engine_set_colon_line_handler (engine_t engine,
 				      void *fnc_value);
 gpgme_error_t _gpgme_engine_op_decrypt (engine_t engine, gpgme_data_t ciph,
 					gpgme_data_t plain,
-                                        int export_session_key);
+                                        int export_session_key,
+                                        const char *override_session_key);
 gpgme_error_t _gpgme_engine_op_decrypt_verify (engine_t engine,
 					       gpgme_data_t ciph,
 					       gpgme_data_t plain,
-                                               int export_session_key);
+                                               int export_session_key,
+                                               const char *override_session_key
+                                               );
 gpgme_error_t _gpgme_engine_op_delete (engine_t engine, gpgme_key_t key,
 				       int allow_secret);
 gpgme_error_t _gpgme_engine_op_edit (engine_t engine, int type,
diff --git a/src/gpgme.c b/src/gpgme.c
index 32abc282..1a10fd91 100644
--- a/src/gpgme.c
+++ b/src/gpgme.c
@@ -247,6 +247,7 @@ gpgme_release (gpgme_ctx_t ctx)
   free (ctx->signers);
   free (ctx->lc_ctype);
   free (ctx->lc_messages);
+  free (ctx->override_session_key);
   _gpgme_engine_info_release (ctx->engine_info);
   ctx->engine_info = NULL;
   DESTROY_LOCK (ctx->lock);
@@ -515,6 +516,17 @@ gpgme_set_ctx_flag (gpgme_ctx_t ctx, const char *name, const char *value)
     {
       ctx->raw_description = abool;
     }
+  else if (!strcmp (name, "export-session-key"))
+    {
+      ctx->export_session_keys = abool;
+    }
+  else if (!strcmp (name, "override-session-key"))
+    {
+      free (ctx->override_session_key);
+      ctx->override_session_key = strdup (value);
+      if (!ctx->override_session_key)
+        err = gpg_error_from_syserror ();
+    }
   else
     err = gpg_error (GPG_ERR_UNKNOWN_NAME);
 
@@ -526,7 +538,7 @@ gpgme_set_ctx_flag (gpgme_ctx_t ctx, const char *name, const char *value)
  * of valid names.  If the NAME is unknown NULL is returned.  For a
  * boolean flag an empty string is returned for False and the string
  * "1" for True; thus either atoi or a simple string test can be
- * used. */
+ * used.  */
 const char *
 gpgme_get_ctx_flag (gpgme_ctx_t ctx, const char *name)
 {
@@ -540,35 +552,19 @@ gpgme_get_ctx_flag (gpgme_ctx_t ctx, const char *name)
     {
       return ctx->raw_description? "1":"";
     }
+  else if (!strcmp (name, "export-session-key"))
+    {
+      return ctx->export_session_keys? "1":"";
+    }
+  else if (!strcmp (name, "override-session-key"))
+    {
+      return ctx->override_session_key? ctx->override_session_key : "";
+    }
   else
     return NULL;
 }
 
 
-/* Enable or disable the exporting session keys upon decryption.  */
-void
-gpgme_set_export_session_keys (gpgme_ctx_t ctx, int export_session_keys)
-{
-  TRACE2 (DEBUG_CTX, "gpgme_set_export_session_keys", ctx, "export_session_keys=%i (%s)",
-	  export_session_keys, export_session_keys ? "yes" : "no");
-
-  if (!ctx)
-    return;
-
-  ctx->export_session_keys = !!export_session_keys;
-}
-
-
-/* Return whether this context will export session keys upon decryption.  */
-int
-gpgme_get_export_session_keys (gpgme_ctx_t ctx)
-{
-  TRACE2 (DEBUG_CTX, "gpgme_get_export_session_keys", ctx, "ctx->export_session_keys=%i (%s)",
-	  ctx->export_session_keys, ctx->export_session_keys ? "yes" : "no");
-  return ctx->export_session_keys;
-}
-
-
 /* Enable or disable the use of the special textmode.  Textmode is for
   example used for the RFC2015 signatures; note that the updated RFC
   3156 mandates that the MUA does some preparations so that textmode
diff --git a/src/gpgme.def b/src/gpgme.def
index cd0d0848..0d3ce74f 100644
--- a/src/gpgme.def
+++ b/src/gpgme.def
@@ -252,8 +252,6 @@ EXPORTS
     gpgme_op_query_swdb                   @189
     gpgme_op_query_swdb_result            @190
 
-    gpgme_set_export_session_keys         @191
-    gpgme_get_export_session_keys         @192
-    gpgme_get_ctx_flag                    @193
+    gpgme_get_ctx_flag                    @191
 ; END
 
diff --git a/src/gpgme.h.in b/src/gpgme.h.in
index 43e07b06..7cfe8f65 100644
--- a/src/gpgme.h.in
+++ b/src/gpgme.h.in
@@ -1040,13 +1040,6 @@ void gpgme_set_offline (gpgme_ctx_t ctx, int yes);
 /* Return non-zero if offline mode is set in CTX.  */
 int gpgme_get_offline (gpgme_ctx_t ctx);
 
-/* If YES is non-zero, try to return session keys during decryption,
-   do not otherwise.  */
-void gpgme_set_export_session_keys (gpgme_ctx_t ctx, int yes);
-
-/* Return non-zero if export_session_keys is set in CTX.  */
-int gpgme_get_export_session_keys (gpgme_ctx_t ctx);
-
 /* Use whatever the default of the backend crypto engine is.  */
 #define GPGME_INCLUDE_CERTS_DEFAULT	-256
 
diff --git a/src/libgpgme.vers b/src/libgpgme.vers
index 362909ae..a55cd10a 100644
--- a/src/libgpgme.vers
+++ b/src/libgpgme.vers
@@ -126,9 +126,6 @@ GPGME_1.1 {
 
     gpgme_op_query_swdb;
     gpgme_op_query_swdb_result;
-
-    gpgme_set_export_session_keys;
-    gpgme_get_export_session_keys;
 };