[gmime] Implemented session-keys upport for GMimePkcs7Context

[Jeffrey Stedfast <fejj src gnome org>]

commit 41a9c4ed770c06f404bf39a1c284267fde23e3e2
Author: Jeffrey Stedfast <fejj gnome org>
Date:   Sat Feb 18 15:40:19 2017 -0500

    Implemented session-keys upport for GMimePkcs7Context

 gmime/gmime-gpg-context.c   |   16 ++++++++-
 gmime/gmime-pkcs7-context.c |   76 +++++++++++++++++++++++++++++++++++++++---
 2 files changed, 84 insertions(+), 8 deletions(-)
---
diff --git a/gmime/gmime-gpg-context.c b/gmime/gmime-gpg-context.c
index 75ff151..d61c70c 100644
--- a/gmime/gmime-gpg-context.c
+++ b/gmime/gmime-gpg-context.c
@@ -803,8 +803,6 @@ gpg_decrypt_session (GMimeCryptoContext *context, const char *session_key,
        gpgme_data_t input, output;
        gpgme_error_t error;
        
-       // TODO: make use of the session_key
-       
        if ((error = gpgme_data_new_from_cbs (&input, &gpg_stream_funcs, istream)) != GPG_ERR_NO_ERROR) {
                g_set_error (err, GMIME_GPGME_ERROR, error, _("Could not open input stream"));
                return NULL;
@@ -816,14 +814,18 @@ gpg_decrypt_session (GMimeCryptoContext *context, const char *session_key,
                return NULL;
        }
        
+       gpgme_set_ctx_flag (gpg->ctx, "override-session-key", session_key);
+       
        /* decrypt the input stream */
        if ((error = gpgme_op_decrypt_verify (gpg->ctx, input, output)) != GPG_ERR_NO_ERROR) {
                g_set_error (err, GMIME_GPGME_ERROR, error, _("Decryption failed"));
+               gpgme_set_ctx_flag (gpg->ctx, "override-session-key", NULL);
                gpgme_data_release (output);
                gpgme_data_release (input);
                return NULL;
        }
        
+       gpgme_set_ctx_flag (gpg->ctx, "override-session-key", NULL);
        gpgme_data_release (output);
        gpgme_data_release (input);
        
@@ -900,18 +902,23 @@ gpg_export_keys (GMimeCryptoContext *context, const char *keys[], GMimeStream *o
 static gboolean
 gpg_get_retrieve_session_key (GMimeCryptoContext *context)
 {
+#ifdef ENABLE_CRYPTO
        GMimeGpgContext *ctx = (GMimeGpgContext *) context;
        const char *value;
        
        value = gpgme_get_ctx_flag (ctx->ctx, "export-session-key");
        
        return value && *value && *value != '0';
+#else
+       return FALSE;
+#endif /* ENABLE_CRYPTO */
 }
 
 
 static int
 gpg_set_retrieve_session_key (GMimeCryptoContext *context, gboolean retrieve_session_key, GError **err)
 {
+#ifdef ENABLE_CRYPTO
        GMimeGpgContext *ctx = (GMimeGpgContext *) context;
        gpgme_error_t error;
        
@@ -922,6 +929,11 @@ gpg_set_retrieve_session_key (GMimeCryptoContext *context, gboolean retrieve_ses
        }
        
        return 0;
+#else
+       g_set_error (err, GMIME_ERROR, GMIME_ERROR_NOT_SUPPORTED,
+                    _("Session key retrieval is not supported by this crypto context"));
+       return -1;
+#endif /* ENABLE_CRYPTO */
 }
 
 static gboolean
diff --git a/gmime/gmime-pkcs7-context.c b/gmime/gmime-pkcs7-context.c
index c154409..f67d029 100644
--- a/gmime/gmime-pkcs7-context.c
+++ b/gmime/gmime-pkcs7-context.c
@@ -84,13 +84,17 @@ static void g_mime_pkcs7_context_init (GMimePkcs7Context *ctx, GMimePkcs7Context
 static void g_mime_pkcs7_context_finalize (GObject *object);
 
 static GMimeDigestAlgo pkcs7_digest_id (GMimeCryptoContext *ctx, const char *name);
-
 static const char *pkcs7_digest_name (GMimeCryptoContext *ctx, GMimeDigestAlgo digest);
 
-static const char *pkcs7_get_signature_protocol (GMimeCryptoContext *ctx);
+static gboolean pkcs7_get_retrieve_session_key (GMimeCryptoContext *context);
+static int pkcs7_set_retrieve_session_key (GMimeCryptoContext *ctx, gboolean retrieve_session_key,
+                                          GError **err);
 
-static const char *pkcs7_get_encryption_protocol (GMimeCryptoContext *ctx);
+static gboolean pkcs7_get_always_trust (GMimeCryptoContext *context);
+static void pkcs7_set_always_trust (GMimeCryptoContext *ctx, gboolean always_trust);
 
+static const char *pkcs7_get_signature_protocol (GMimeCryptoContext *ctx);
+static const char *pkcs7_get_encryption_protocol (GMimeCryptoContext *ctx);
 static const char *pkcs7_get_key_exchange_protocol (GMimeCryptoContext *ctx);
 
 static int pkcs7_sign (GMimeCryptoContext *ctx, gboolean detach,
@@ -109,15 +113,16 @@ static int pkcs7_encrypt (GMimeCryptoContext *ctx, gboolean sign, const char *us
 static GMimeDecryptResult *pkcs7_decrypt (GMimeCryptoContext *ctx, GMimeStream *istream,
                                          GMimeStream *ostream, GError **err);
 
+static GMimeDecryptResult *pkcs7_decrypt_session (GMimeCryptoContext *ctx, const char *session_key,
+                                                 GMimeStream *istream, GMimeStream *ostream,
+                                               GError **err);
+
 static int pkcs7_import_keys (GMimeCryptoContext *ctx, GMimeStream *istream,
                              GError **err);
 
 static int pkcs7_export_keys (GMimeCryptoContext *ctx, const char *keys[],
                              GMimeStream *ostream, GError **err);
 
-static gboolean pkcs7_get_always_trust (GMimeCryptoContext *context);
-static void pkcs7_set_always_trust (GMimeCryptoContext *ctx, gboolean always_trust);
-
 
 static GMimeCryptoContextClass *parent_class = NULL;
 
@@ -163,11 +168,14 @@ g_mime_pkcs7_context_class_init (GMimePkcs7ContextClass *klass)
        crypto_class->verify = pkcs7_verify;
        crypto_class->encrypt = pkcs7_encrypt;
        crypto_class->decrypt = pkcs7_decrypt;
+       crypto_class->decrypt_session = pkcs7_decrypt_session;
        crypto_class->import_keys = pkcs7_import_keys;
        crypto_class->export_keys = pkcs7_export_keys;
        crypto_class->get_signature_protocol = pkcs7_get_signature_protocol;
        crypto_class->get_encryption_protocol = pkcs7_get_encryption_protocol;
        crypto_class->get_key_exchange_protocol = pkcs7_get_key_exchange_protocol;
+       crypto_class->get_retrieve_session_key = pkcs7_get_retrieve_session_key;
+       crypto_class->set_retrieve_session_key = pkcs7_set_retrieve_session_key;
        crypto_class->get_always_trust = pkcs7_get_always_trust;
        crypto_class->set_always_trust = pkcs7_set_always_trust;
 }
@@ -737,9 +745,14 @@ pkcs7_get_decrypt_result (GMimePkcs7Context *pkcs7)
        result->recipients = g_mime_certificate_list_new ();
        result->signatures = pkcs7_get_signatures (pkcs7, FALSE);
        
+       // TODO: ciper, mdc
+       
        if (!(res = gpgme_op_decrypt_result (pkcs7->ctx)) || !res->recipients)
                return result;
        
+       if (res->session_key)
+               result->session_key = g_strdup (res->session_key);
+       
        recipient = res->recipients;
        while (recipient != NULL) {
                cert = g_mime_certificate_new ();
@@ -759,6 +772,14 @@ static GMimeDecryptResult *
 pkcs7_decrypt (GMimeCryptoContext *context, GMimeStream *istream,
               GMimeStream *ostream, GError **err)
 {
+       return pkcs7_decrypt_session (context, NULL, istream, ostream, err);
+}
+
+static GMimeDecryptResult *
+pkcs7_decrypt_session (GMimeCryptoContext *context, const char *session_key,
+                      GMimeStream *istream, GMimeStream *ostream,
+                      GError **err)
+{
 #ifdef ENABLE_CRYPTO
        GMimePkcs7Context *pkcs7 = (GMimePkcs7Context *) context;
        GMimeDecryptResult *result;
@@ -777,14 +798,18 @@ pkcs7_decrypt (GMimeCryptoContext *context, GMimeStream *istream,
                return NULL;
        }
        
+       gpgme_set_ctx_flag (pkcs7->ctx, "override-session-key", session_key);
+       
        /* decrypt the input stream */
        if ((error = gpgme_op_decrypt_verify (pkcs7->ctx, input, output)) != GPG_ERR_NO_ERROR) {
                g_set_error (err, GMIME_GPGME_ERROR, error, _("Decryption failed"));
+               gpgme_set_ctx_flag (pkcs7->ctx, "override-session-key", NULL);
                gpgme_data_release (output);
                gpgme_data_release (input);
                return NULL;
        }
        
+       gpgme_set_ctx_flag (pkcs7->ctx, "override-session-key", NULL);
        gpgme_data_release (output);
        gpgme_data_release (input);
        
@@ -860,6 +885,44 @@ pkcs7_export_keys (GMimeCryptoContext *context, const char *keys[], GMimeStream
 
 
 static gboolean
+pkcs7_get_retrieve_session_key (GMimeCryptoContext *context)
+{
+#ifdef ENABLE_CRYPTO
+       GMimePkcs7Context *ctx = (GMimePkcs7Context *) context;
+       const char *value;
+       
+       value = gpgme_get_ctx_flag (ctx->ctx, "export-session-key");
+       
+       return value && *value && *value != '0';
+#else
+       return FALSE;
+#endif /* ENABLE_CRYPTO */
+}
+
+
+static int
+pkcs7_set_retrieve_session_key (GMimeCryptoContext *context, gboolean retrieve_session_key, GError **err)
+{
+#ifdef ENABLE_CRYPTO
+       GMimePkcs7Context *ctx = (GMimePkcs7Context *) context;
+       gpgme_error_t error;
+       
+       if ((error = gpgme_set_ctx_flag (ctx->ctx, "export-session-key", retrieve_session_key ? "1" : "0")) 
!= 0) {
+               g_set_error (err, GMIME_ERROR, GMIME_ERROR_NOT_SUPPORTED,
+                            _("Session key retrieval is not supported by this crypto context"));
+               return -1;
+       }
+       
+       return 0;
+#else
+       g_set_error (err, GMIME_ERROR, GMIME_ERROR_NOT_SUPPORTED,
+                    _("Session key retrieval is not supported by this crypto context"));
+       return -1;
+#endif /* ENABLE_CRYPTO */
+}
+
+
+static gboolean
 pkcs7_get_always_trust (GMimeCryptoContext *context)
 {
 #ifdef ENABLE_CRYPTO
@@ -871,6 +934,7 @@ pkcs7_get_always_trust (GMimeCryptoContext *context)
 #endif /* ENABLE_CRYPTO */
 }
 
+
 static void
 pkcs7_set_always_trust (GMimeCryptoContext *context, gboolean always_trust)
 {