2003-02-02 Havoc Pennington <hp@pobox.com>

	* dbus/dbus-keyring.c, dbus/dbus-keyring.h: template files
	for code to manage cookies in your home directory

	* dbus/dbus-sysdeps.c (_dbus_generate_random_bytes): new function

	* dbus/dbus-auth.c (get_state): impose a maximum number of tries
	to authenticate, then disconnect the client.

6 files changed, 243 insertions, 2 deletions

diff --git a/dbus/dbus-auth.c b/dbus/dbus-auth.c
index 348cd27c..55b2c9b5 100644
--- a/dbus/dbus-auth.c
+++ b/dbus/dbus-auth.c
@@ -147,7 +147,7 @@ typedef struct
 {
   DBusAuth base;
 
-  DBusList *mechs_to_try;
+  DBusList *mechs_to_try; /**< Mechanisms we got from the server that we're going to try using */
   
 } DBusAuthClient;
 
@@ -155,6 +155,9 @@ typedef struct
 {
   DBusAuth base;
 
+  int failures;     /**< Number of times client has been rejected */
+  int max_failures; /**< Number of times we reject before disconnect */
+  
 } DBusAuthServer;
 
 static dbus_bool_t process_auth         (DBusAuth         *auth,
@@ -283,6 +286,11 @@ _dbus_auth_new (int size)
 static DBusAuthState
 get_state (DBusAuth *auth)
 {
+  if (DBUS_AUTH_IS_SERVER (auth) &&
+      DBUS_AUTH_SERVER (auth)->failures >=
+      DBUS_AUTH_SERVER (auth)->max_failures)
+    auth->need_disconnect = TRUE;
+  
   if (auth->need_disconnect)
     return DBUS_AUTH_STATE_NEED_DISCONNECT;
   else if (auth->authenticated)
@@ -585,6 +593,7 @@ static dbus_bool_t
 send_rejected (DBusAuth *auth)
 {
   DBusString command;
+  DBusAuthServer *server_auth;
   int i;
   
   if (!_dbus_string_init (&command, _DBUS_INT_MAX))
@@ -614,6 +623,10 @@ send_rejected (DBusAuth *auth)
   if (!_dbus_string_copy (&command, 0, &auth->outgoing,
                           _dbus_string_get_length (&auth->outgoing)))
     goto nomem;
+
+  _dbus_assert (DBUS_AUTH_IS_SERVER (auth));
+  server_auth = DBUS_AUTH_SERVER (auth);
+  server_auth->failures += 1;
   
   return TRUE;
 
@@ -1170,12 +1183,21 @@ DBusAuth*
 _dbus_auth_server_new (void)
 {
   DBusAuth *auth;
+  DBusAuthServer *server_auth;
 
   auth = _dbus_auth_new (sizeof (DBusAuthServer));
   if (auth == NULL)
     return NULL;
 
   auth->handlers = server_handlers;
+
+  server_auth = DBUS_AUTH_SERVER (auth);
+
+  /* perhaps this should be per-mechanism with a lower
+   * max
+   */
+  server_auth->failures = 0;
+  server_auth->max_failures = 6;
   
   return auth;
 }
diff --git a/dbus/dbus-keyring.c b/dbus/dbus-keyring.c
new file mode 100644
index 00000000..32695bb9
--- /dev/null
+++ b/dbus/dbus-keyring.c
@@ -0,0 +1,95 @@
+/* -*- mode: C; c-file-style: "gnu" -*- */
+/* dbus-keyring.c Store secret cookies in your homedir
+ *
+ * Copyright (C) 2003  Red Hat Inc.
+ *
+ * Licensed under the Academic Free License version 1.2
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#include "dbus-keyring.h"
+#include <dbus/dbus-string.h>
+#include <dbus/dbus-list.h>
+#include <dbus/dbus-sysdeps.h>
+
+/**
+ * @defgroup DBusKeyring keyring class
+ * @ingroup  DBusInternals
+ * @brief DBusKeyring data structure
+ *
+ * Types and functions related to DBusKeyring. DBusKeyring is intended
+ * to manage cookies used to authenticate clients to servers.  This is
+ * essentially the "verify that client can read the user's homedir"
+ * authentication mechanism.  Both client and server must have access
+ * to the homedir.
+ *
+ * The secret keys are not kept in locked memory, and are written to a
+ * file in the user's homedir. However they are transient (only used
+ * by a single server instance for a fixed period of time, then
+ * discarded). Also, the keys are not sent over the wire.
+ */
+
+/**
+ * @defgroup DBusKeyringInternals DBusKeyring implementation details
+ * @ingroup  DBusInternals
+ * @brief DBusKeyring implementation details
+ *
+ * The guts of DBusKeyring.
+ *
+ * @{
+ */
+
+typedef struct
+{
+  dbus_uint32_t id; /**< identifier used to refer to the key */
+
+  unsigned long creation_time; /**< when the key was generated,
+                                *   as unix timestamp
+                                */
+
+  DBusString context; /**< Name of kind of server using this
+                       *   key, for example "desktop_session_bus"
+                       */
+  
+  DBusString secret; /**< the actual key */
+
+} DBusKey;
+
+/**
+ * @brief Internals of DBusKeyring.
+ * 
+ * DBusKeyring internals. DBusKeyring is an opaque object, it must be
+ * used via accessor functions.
+ */
+struct DBusKeyring
+{
+  DBusString filename;
+  DBusString lock_filename;
+  
+  
+};
+
+/** @} */ /* end of internals */
+
+/**
+ * @addtogroup DBusKeyring
+ *
+ * @{
+ */
+
+
+/** @} */ /* end of public API */
diff --git a/dbus/dbus-keyring.h b/dbus/dbus-keyring.h
new file mode 100644
index 00000000..c60c64ef
--- /dev/null
+++ b/dbus/dbus-keyring.h
@@ -0,0 +1,50 @@
+/* -*- mode: C; c-file-style: "gnu" -*- */
+/* dbus-keyring.h Store secret cookies in your homedir
+ *
+ * Copyright (C) 2003  Red Hat Inc.
+ *
+ * Licensed under the Academic Free License version 1.2
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+#ifndef DBUS_KEYRING_H
+#define DBUS_KEYRING_H
+
+#include <dbus/dbus-macros.h>
+#include <dbus/dbus-errors.h>
+
+DBUS_BEGIN_DECLS;
+
+typedef struct DBusKeyring DBusKeyring;
+
+
+DBusKeyring* _dbus_keyring_load             (const char       *context,
+                                             DBusResultCode   *result);
+void         _dbus_keyring_ref              (DBusKeyring      *keyring);
+void         _dbus_keyring_unref            (DBusKeyring      *keyring);
+dbus_bool_t  _dbus_keyring_create_challenge (DBusKeyring      *keyring,
+                                             DBusString       *challenge);
+dbus_bool_t  _dbus_keyring_compute_response (DBusKeyring      *keyring,
+                                             const DBusString *challenge,
+                                             DBusString       *response);
+dbus_bool_t  _dbus_keyring_check_response   (DBusKeyring      *keyring,
+                                             const DBusString *challenge,
+                                             const DBusString *response);
+
+
+DBUS_END_DECLS;
+
+#endif /* DBUS_KEYRING_H */
diff --git a/dbus/dbus-string.c b/dbus/dbus-string.c
index 17a7d918..a5bf3ebc 100644
--- a/dbus/dbus-string.c
+++ b/dbus/dbus-string.c
@@ -374,7 +374,11 @@ _dbus_string_get_data (DBusString        *str,
 }
 
 /**
- * Gets the raw character buffer from a const string. 
+ * Gets the raw character buffer from a const string.
+ *
+ * @todo should return the const char* instead of using an out param;
+ * the temporary variable encourages a bug where you use const data
+ * after modifying the string and possibly causing a realloc.
  *
  * @param str the string
  * @param data_return location to store returned data
@@ -420,6 +424,10 @@ _dbus_string_get_data_len (DBusString *str,
 /**
  * const version of _dbus_string_get_data_len().
  *
+ * @todo should return the const char* instead of using an out param;
+ * the temporary variable encourages a bug where you use const data
+ * after modifying the string and possibly causing a realloc.
+ * 
  * @param str the string
  * @param data_return location to return the buffer
  * @param start byte offset to return
diff --git a/dbus/dbus-sysdeps.c b/dbus/dbus-sysdeps.c
index db5118a5..38efb0cd 100644
--- a/dbus/dbus-sysdeps.c
+++ b/dbus/dbus-sysdeps.c
@@ -1336,5 +1336,68 @@ _dbus_directory_close (DBusDirIter *iter)
   dbus_free (iter);
 }
 
+/**
+ * Generates the given number of random bytes,
+ * using the best mechanism we can come up with.
+ *
+ * @param str the string
+ * @param n_bytes the number of random bytes to append to string
+ * @returns #TRUE on success, #FALSE if no memory or other failure
+ */
+dbus_bool_t
+_dbus_generate_random_bytes (DBusString *str,
+                             int         n_bytes)
+{
+  int old_len;
+  int fd;
+  
+  old_len = _dbus_string_get_length (str);
+  fd = -1;
+
+  /* note, urandom on linux will fall back to pseudorandom */
+  fd = open ("/dev/urandom", O_RDONLY);
+  if (fd < 0)
+    {
+      unsigned long tv_usec;
+      int i;
+
+      /* fall back to pseudorandom */
+      
+      _dbus_get_current_time (NULL, &tv_usec);
+      srand (tv_usec);
+      
+      i = 0;
+      while (i < n_bytes)
+        {
+          double r;
+          int b;
+          
+          r = rand ();
+          b = (r / (double) RAND_MAX) * 255.0;
+          
+          if (!_dbus_string_append_byte (str, b))
+            goto failed;
+          
+          ++i;
+        }
+
+      return TRUE;
+    }
+  else
+    {
+      if (_dbus_read (fd, str, n_bytes) != n_bytes)
+        goto failed;
+
+      close (fd);
+
+      return TRUE;
+    }
+
+ failed:
+  _dbus_string_set_length (str, old_len);
+  if (fd >= 0)
+    close (fd);
+  return FALSE;
+}
 
 /** @} end of sysdeps */
diff --git a/dbus/dbus-sysdeps.h b/dbus/dbus-sysdeps.h
index fd0d93de..3212a237 100644
--- a/dbus/dbus-sysdeps.h
+++ b/dbus/dbus-sysdeps.h
@@ -140,6 +140,9 @@ dbus_bool_t  _dbus_directory_get_next_file (DBusDirIter      *iter,
 void         _dbus_directory_close         (DBusDirIter      *iter);
 
 
+dbus_bool_t _dbus_generate_random_bytes (DBusString *str,
+                                         int         n_bytes);
+
 DBUS_END_DECLS;
 
 #endif /* DBUS_SYSDEPS_H */