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

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* 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 <wk@gnupg.org>
This commit is contained in:
Werner Koch 2016-11-15 10:29:48 +01:00
parent 3234b1bf1d
commit 7659d42468
No known key found for this signature in database
GPG Key ID: E3FDFF218E45B72B
15 changed files with 128 additions and 97 deletions
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66
doc/gpgme.texi
View File

@ -191,7 +191,6 @@ Context Attributes
* Text Mode:: Choosing canonical text mode.
* Offline Mode:: Choosing offline mode.
* Included Certificates:: Including a number of certificates.
* Exporting Session Keys:: Requesting session keys upon decryption.
* Key Listing Mode:: Selecting key listing mode.
* Passphrase Callback:: Getting the passphrase from the user.
* Progress Meter Callback:: Being informed about the progress.
@ -2314,10 +2313,12 @@ The function @code{gpgme_release} destroys the context with the handle
The detailed result of an operation is returned in operation-specific
structures such as @code{gpgme_decrypt_result_t}. The corresponding
retrieval functions such as @code{gpgme_op_decrypt_result} provide
static access to the results after an operation completes. The
following interfaces make it possible to detach a result structure
from its associated context and give it a lifetime beyond that of the
current operation or context.
static access to the results after an operation completes. Those
structures shall be considered read-only and an application must not
allocated such a strucure on its own. The following interfaces make
it possible to detach a result structure from its associated context
and give it a lifetime beyond that of the current operation or
context.
@deftypefun void gpgme_result_ref (@w{void *@var{result}})
The function @code{gpgme_result_ref} acquires an additional reference
@ -2352,7 +2353,6 @@ started. In fact, these references are accessed through the
* Offline Mode:: Choosing offline mode.
* Pinentry Mode:: Choosing the pinentry mode.
* Included Certificates:: Including a number of certificates.
* Exporting Session Keys:: Requesting session keys upon decryption.
* Key Listing Mode:: Selecting key listing mode.
* Passphrase Callback:: Getting the passphrase from the user.
* Progress Meter Callback:: Being informed about the progress.
@ -2643,29 +2643,6 @@ certificates to include into an S/MIME signed message.
@end deftypefun
@node Exporting Session Keys
@subsection Exporting Session Keys
@cindex context, exporting session keys
@cindex Exporting Session Keys
@cindex exporting session keys
@deftypefun void gpgme_set_export_session_keys (@w{gpgme_ctx_t @var{ctx}}, @w{int @var{yes}})
The function @code{gpgme_set_export_session_keys} specifies whether
the context should try to export the symmetric session key when
decrypting data. By default, session keys are not exported.
Session keys are not exported if @var{yes} is zero, and
enabled otherwise.
@end deftypefun
@deftypefun int gpgme_get_export_session_keys (@w{gpgme_ctx_t @var{ctx}})
The function @code{gpgme_get_export_session_keys} returns @code{1} if
the context will try to export the symmetric session key when
decrypting, and @code{0} if not, or if @var{ctx} is not a valid
pointer.
@end deftypefun
@node Key Listing Mode
@subsection Key Listing Mode
@cindex key listing mode
@ -2923,6 +2900,18 @@ format. For example the non breaking space characters ("~") will not
be removed from the @code{description} field of the
@code{gpgme_tofu_info_t} object.
@item "export-session-key"
Using a @var{value} of "1" specifies that the context should try to
export the symmetric session key when decrypting data. By default, or
when using an empty string or "0" for @var{value}, session keys are
not exported.
@item "override-session-key"
The string given in @var{value} is passed to the GnuPG engine to override
the session key for decryption. The format of that session key is
specific to GnuPG and can be retrieved during a decrypt operation when
the context flag "export-session-key" is enabled.
@end table
This function returns @code{0} on success.
@ -4798,8 +4787,10 @@ secret key for this recipient is not available, and 0 otherwise.
This is a pointer to a structure used to store the result of a
@code{gpgme_op_decrypt} operation. After successfully decrypting
data, you can retrieve the pointer to the result with
@code{gpgme_op_decrypt_result}. The structure contains the following
members:
@code{gpgme_op_decrypt_result}. As with all result structures, it
this structure shall be considered read-only and an application must
not allocated such a strucure on its own. The structure contains the
following members:
@table @code
@item char *unsupported_algorithm
@ -4817,17 +4808,12 @@ This is the filename of the original plaintext message file if it is
known, otherwise this is a null pointer.
@item char *session_key
A textual representation (null-terminated string) of the session key
A textual representation (nul-terminated string) of the session key
used in symmetric encryption of the message, if the context has been
set to export session keys (see @code{gpgme_get_export_session_keys}
and @code{gpgme_set_export_session_keys}), and a session key was
available for the most recent decryption operation. Otherwise, this
is a null pointer.
set to export session keys (see @code{gpgme_set_ctx_flag,
"export-session-key"}), and a session key was available for the most
recent decryption operation. Otherwise, this is a null pointer.
You should never access this member of a
@code{gpgme_op_decrypt_result_t} without first ensuring that
@code{gpgme_get_export_session_keys} returns non-zero for the
reporting context.
@end table
@end deftp

3
src/context.h
View File

@ -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;

4
src/decrypt-verify.c
View File

@ -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);
}

4
src/decrypt.c
View File

@ -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);
}

6
src/engine-backend.h
View File

@ -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 */);

10
src/engine-gpg.c
View File

@ -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");

5
src/engine-gpgsm.c
View File

@ -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);

18
src/engine-uiserver.c
View File

@ -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);
}

13
src/engine.c
View File

@ -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);
}

7
src/engine.h
View File

@ -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,

44
src/gpgme.c
View File

@ -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);
@ -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

4
src/gpgme.def
View File

@ -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

7
src/gpgme.h.in
View File

@ -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

3
src/libgpgme.vers
View File

@ -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;
};

27
tests/run-decrypt.c
View File

@ -51,9 +51,13 @@ print_result (gpgme_decrypt_result_t result)
{
gpgme_recipient_t recp;
int count = 0;
printf ("Original file name: %s\n", nonnull(result->file_name));
printf ("Wrong key usage: %i\n", result->wrong_key_usage);
printf ("Unsupported algorithm: %s\n ", nonnull(result->unsupported_algorithm));
printf ("Unsupported algorithm: %s\n",
nonnull(result->unsupported_algorithm));
if (result->session_key)
printf ("Session key: %s\n", result->session_key);
for (recp = result->recipients; recp->next; recp = recp->next)
{
@ -74,6 +78,8 @@ show_usage (int ex)
" --status print status lines from the backend\n"
" --openpgp use the OpenPGP protocol (default)\n"
" --cms use the CMS protocol\n"
" --export-session-key show the session key\n"
" --override-session-key STRING use STRING as session key\n"
, stderr);
exit (ex);
}
@ -91,6 +97,8 @@ main (int argc, char **argv)
gpgme_data_t out = NULL;
gpgme_decrypt_result_t result;
int print_status = 0;
int export_session_key = 0;
const char *override_session_key = NULL;
if (argc)
{ argc--; argv++; }
@ -125,6 +133,19 @@ main (int argc, char **argv)
protocol = GPGME_PROTOCOL_CMS;
argc--; argv++;
}
else if (!strcmp (*argv, "--export-session-key"))
{
export_session_key = 1;
argc--; argv++;
}
else if (!strcmp (*argv, "--override-session-key"))
{
argc--; argv++;
if (!argc)
show_usage (1);
override_session_key = *argv;
argc--; argv++;
}
else if (!strncmp (*argv, "--", 2))
show_usage (1);
@ -152,6 +173,10 @@ main (int argc, char **argv)
gpgme_set_status_cb (ctx, status_cb, NULL);
gpgme_set_ctx_flag (ctx, "full-status", "1");
}
if (export_session_key)
gpgme_set_ctx_flag (ctx, "export-session-key", "1");
if (override_session_key)
gpgme_set_ctx_flag (ctx, "override-session-key", override_session_key);
err = gpgme_data_new_from_stream (&in, fp_in);
if (err)