[Spice-devel] [PATCH v3] Report invalid password as a special auth error

[Cédric Bosdonnat]

Provide a special authentication error message for too long passwords.
Also check for too long passwords before sending them over the wire.
---
 Diff to v2:
   * Make spice_channel_send_spice_ticket return TRUE / FALSE to indicate success

 gtk/spice-channel.c | 74 ++++++++++++++++++++++++++++++++++-------------------
 gtk/spice-client.h  |  2 ++
 2 files changed, 50 insertions(+), 26 deletions(-)

diff --git a/gtk/spice-channel.c b/gtk/spice-channel.c
index 4e7d8b7..bd7998a 100644
--- a/gtk/spice-channel.c
+++ b/gtk/spice-channel.c
@@ -1010,7 +1010,34 @@ static int spice_channel_read(SpiceChannel *channel, void *data, size_t length)
 }
 
 /* coroutine context */
-static void spice_channel_send_spice_ticket(SpiceChannel *channel)
+static void spice_channel_failed_authentication(SpiceChannel *channel,
+                                                gboolean invalidPassword)
+{
+    SpiceChannelPrivate *c = channel->priv;
+
+    if (c->auth_needs_username_and_password)
+        g_set_error_literal(&c->error,
+                            SPICE_CLIENT_ERROR,
+                            SPICE_CLIENT_ERROR_AUTH_NEEDS_PASSWORD_AND_USERNAME,
+                            _("Authentication failed: password and username are required"));
+    else if (invalidPassword)
+        g_set_error_literal(&c->error,
+                            SPICE_CLIENT_ERROR,
+                            SPICE_CLIENT_ERROR_AUTH_INVALID_PASSWORD,
+                            _("Authentication failed: password is too long"));
+    else
+        g_set_error_literal(&c->error,
+                            SPICE_CLIENT_ERROR,
+                            SPICE_CLIENT_ERROR_AUTH_NEEDS_PASSWORD,
+                            _("Authentication failed: password is required"));
+
+    c->event = SPICE_CHANNEL_ERROR_AUTH;
+
+    c->has_error = TRUE; /* force disconnect */
+}
+
+/* coroutine context */
+static gboolean spice_channel_send_spice_ticket(SpiceChannel *channel)
 {
     SpiceChannelPrivate *c = channel->priv;
     EVP_PKEY *pubkey;
@@ -1020,6 +1047,7 @@ static void spice_channel_send_spice_ticket(SpiceChannel *channel)
     char *password;
     uint8_t *encrypted;
     int rc;
+    gboolean ret = FALSE;
 
     bioKey = BIO_new(BIO_s_mem());
     g_return_if_fail(bioKey != NULL);
@@ -1039,36 +1067,24 @@ static void spice_channel_send_spice_ticket(SpiceChannel *channel)
     g_object_get(c->session, "password", &password, NULL);
     if (password == NULL)
         password = g_strdup("");
+    if (strlen(password) > SPICE_MAX_PASSWORD_LENGTH) {
+        spice_channel_failed_authentication(channel, TRUE);
+        goto cleanup;
+    }
     rc = RSA_public_encrypt(strlen(password) + 1, (uint8_t*)password,
                             encrypted, rsa, RSA_PKCS1_OAEP_PADDING);
     g_warn_if_fail(rc > 0);
 
     spice_channel_write(channel, encrypted, nRSASize);
+    ret = TRUE;
+
+cleanup:
     memset(encrypted, 0, nRSASize);
     EVP_PKEY_free(pubkey);
     BIO_free(bioKey);
     g_free(password);
-}
-
-/* coroutine context */
-static void spice_channel_failed_authentication(SpiceChannel *channel)
-{
-    SpiceChannelPrivate *c = channel->priv;
 
-    if (c->auth_needs_username_and_password)
-        g_set_error_literal(&c->error,
-                            SPICE_CLIENT_ERROR,
-                            SPICE_CLIENT_ERROR_AUTH_NEEDS_PASSWORD_AND_USERNAME,
-                            _("Authentication failed: password and username are required"));
-    else
-        g_set_error_literal(&c->error,
-                            SPICE_CLIENT_ERROR,
-                            SPICE_CLIENT_ERROR_AUTH_NEEDS_PASSWORD,
-                            _("Authentication failed: password is required"));
-
-    c->event = SPICE_CHANNEL_ERROR_AUTH;
-
-    c->has_error = TRUE; /* force disconnect */
+    return ret;
 }
 
 /* coroutine context */
@@ -1086,9 +1102,13 @@ static gboolean spice_channel_recv_auth(SpiceChannel *channel)
         return FALSE;
     }
 
-    if (link_res != SPICE_LINK_ERR_OK) {
+    if (link_res == SPICE_LINK_ERR_INVALID_PASSWORD) {
+        CHANNEL_DEBUG(channel, "link result: invalid password");
+        spice_channel_failed_authentication(channel, TRUE);
+        return FALSE;
+    } if (link_res != SPICE_LINK_ERR_OK) {
         CHANNEL_DEBUG(channel, "link result: reply %d", link_res);
-        spice_channel_failed_authentication(channel);
+        spice_channel_failed_authentication(channel, FALSE);
         return FALSE;
     }
 
@@ -1662,7 +1682,7 @@ error:
     if (saslconn)
         sasl_dispose(&saslconn);
 
-    spice_channel_failed_authentication(channel);
+    spice_channel_failed_authentication(channel, FALSE);
     ret = FALSE;
 
 cleanup:
@@ -1733,7 +1753,8 @@ static gboolean spice_channel_recv_link_msg(SpiceChannel *channel)
     if (!spice_channel_test_common_capability(channel,
             SPICE_COMMON_CAP_PROTOCOL_AUTH_SELECTION)) {
         CHANNEL_DEBUG(channel, "Server supports spice ticket auth only");
-        spice_channel_send_spice_ticket(channel);
+        if (!spice_channel_send_spice_ticket(channel))
+            goto error;
     } else {
         SpiceLinkAuthMechanism auth = { 0, };
 
@@ -1749,7 +1770,8 @@ static gboolean spice_channel_recv_link_msg(SpiceChannel *channel)
         if (spice_channel_test_common_capability(channel, SPICE_COMMON_CAP_AUTH_SPICE)) {
             auth.auth_mechanism = SPICE_COMMON_CAP_AUTH_SPICE;
             spice_channel_write(channel, &auth, sizeof(auth));
-            spice_channel_send_spice_ticket(channel);
+            if (!spice_channel_send_spice_ticket(channel))
+                goto error;
         } else {
             g_warning("No compatible AUTH mechanism");
             goto error;
diff --git a/gtk/spice-client.h b/gtk/spice-client.h
index c2474d1..58d1f76 100644
--- a/gtk/spice-client.h
+++ b/gtk/spice-client.h
@@ -60,6 +60,7 @@ G_BEGIN_DECLS
  * @SPICE_CLIENT_USB_DEVICE_LOST: usb device disconnected (fatal IO error)
  * @SPICE_CLIENT_ERROR_AUTH_NEEDS_PASSWORD: password is required
  * @SPICE_CLIENT_ERROR_AUTH_NEEDS_PASSWORD_AND_USERNAME: password and username are required
+ * @SPICE_CLIENT_ERROR_AUTH_INVALID_PASSWORD: password is too long
  *
  * Error codes returned by spice-client API.
  */
@@ -70,6 +71,7 @@ typedef enum
     SPICE_CLIENT_USB_DEVICE_LOST,
     SPICE_CLIENT_ERROR_AUTH_NEEDS_PASSWORD,
     SPICE_CLIENT_ERROR_AUTH_NEEDS_PASSWORD_AND_USERNAME,
+    SPICE_CLIENT_ERROR_AUTH_INVALID_PASSWORD,
 } SpiceClientError;
 
 GQuark spice_client_error_quark(void);
-- 
2.1.4