Attachment 104277 Details for Bug 82346 – [PATCH 2/3] enforce new limit max_connections_per_process

[patch] [PATCH 2/3] enforce new limit max_connections_per_process

0002-enforce-new-limit-max_connections_per_process.patch (text/plain), 7.87 KB, created by Alban Crequy on 2014-08-08 13:02:34 UTC

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Creator: Alban Crequy

Created: 2014-08-08 13:02:34 UTC

Size: 7.87 KB

patch

obsolete

>From 246773ed076e77bafe7106db5e13ea7a37fb6d72 Mon Sep 17 00:00:00 2001
>From: Alban Crequy <alban.crequy@collabora.co.uk>
>Date: Thu, 7 Aug 2014 15:39:56 +0100
>Subject: [PATCH 2/3] enforce new limit max_connections_per_process
>
>https://bugs.freedesktop.org/show_bug.cgi?id=82346
>---
> bus/connection.c | 123 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
> 1 file changed, 118 insertions(+), 5 deletions(-)
>
>diff --git a/bus/connection.c b/bus/connection.c
>index ea2d155..4c19c8c 100644
>--- a/bus/connection.c
>+++ b/bus/connection.c
>@@ -59,6 +59,7 @@ struct BusConnections
>   int n_incomplete;     /**< Length of incomplete list */
>   BusContext *context;
>   DBusHashTable *completed_by_user; /**< Number of completed connections for each UID */
>+  DBusHashTable *completed_by_process; /**< Number of completed connections for each pid */
>   DBusTimeout *expire_timeout; /**< Timeout for expiring incomplete connections. */
>   int stamp;                   /**< Incrementing number */
>   BusExpireList *pending_replies; /**< List of pending replies */
>@@ -90,6 +91,7 @@ typedef struct
>   DBusMessage *oom_message;
>   DBusPreallocatedSend *oom_preallocated;
>   BusClientPolicy *policy;
>+  unsigned long pid;
> 
>   char *cached_loginfo_string;
>   BusSELinuxID *selinux_id;
>@@ -143,6 +145,23 @@ get_connections_for_uid (BusConnections *connections,
>   return current_count;
> }
> 
>+static int
>+get_connections_for_pid (BusConnections *connections,
>+                         dbus_pid_t      pid)
>+{
>+  void *val;
>+  int current_count;
>+
>+  /* val is NULL is 0 when it isn't in the hash yet */
>+
>+  val = _dbus_hash_table_lookup_uintptr (connections->completed_by_process,
>+                                         pid);
>+
>+  current_count = _DBUS_POINTER_TO_INT (val);
>+
>+  return current_count;
>+}
>+
> static dbus_bool_t
> adjust_connections_for_uid (BusConnections *connections,
>                             dbus_uid_t      uid,
>@@ -184,6 +203,47 @@ adjust_connections_for_uid (BusConnections *connections,
>     }
> }
> 
>+static dbus_bool_t
>+adjust_connections_for_pid (BusConnections *connections,
>+                            dbus_pid_t      pid,
>+                            int             adjustment)
>+{
>+  int current_count;
>+
>+  current_count = get_connections_for_pid (connections, pid);
>+
>+  _dbus_verbose ("Adjusting connection count for PID " DBUS_PID_FORMAT
>+                 ": was %d adjustment %d making %d\n",
>+                 pid, current_count, adjustment, current_count + adjustment);
>+
>+  _dbus_assert (current_count >= 0);
>+
>+  current_count += adjustment;
>+
>+  _dbus_assert (current_count >= 0);
>+
>+  if (current_count == 0)
>+    {
>+      _dbus_hash_table_remove_uintptr (connections->completed_by_process, pid);
>+      return TRUE;
>+    }
>+  else
>+    {
>+      dbus_bool_t retval;
>+
>+      retval = _dbus_hash_table_insert_uintptr (connections->completed_by_process,
>+                                              pid, _DBUS_INT_TO_POINTER (current_count));
>+
>+      /* only positive adjustment can fail as otherwise
>+       * a hash entry should already exist
>+       */
>+      _dbus_assert (adjustment > 0 ||
>+                    (adjustment <= 0 && retval));
>+
>+      return retval;
>+    }
>+}
>+
> void
> bus_connection_disconnected (DBusConnection *connection)
> {
>@@ -287,6 +347,12 @@ bus_connection_disconnected (DBusConnection *connection)
>                                                uid, -1))
>                 _dbus_assert_not_reached ("adjusting downward should never fail");
>             }
>+          if (d->pid > 0)
>+            {
>+              if (!adjust_connections_for_pid (d->connections,
>+                                               d->pid, -1))
>+                _dbus_assert_not_reached ("adjusting downward should never fail");
>+            }
>         }
>       else
>         {
>@@ -429,11 +495,16 @@ bus_connections_new (BusContext *context)
>   if (connections->completed_by_user == NULL)
>     goto failed_2;
> 
>+  connections->completed_by_process = _dbus_hash_table_new (DBUS_HASH_UINTPTR,
>+                                                            NULL, NULL);
>+  if (connections->completed_by_process == NULL)
>+    goto failed_3;
>+
>   connections->expire_timeout = _dbus_timeout_new (100, /* irrelevant */
>                                                    expire_incomplete_timeout,
>                                                    connections, NULL);
>   if (connections->expire_timeout == NULL)
>-    goto failed_3;
>+    goto failed_4;
> 
>   _dbus_timeout_set_enabled (connections->expire_timeout, FALSE);
> 
>@@ -442,21 +513,23 @@ bus_connections_new (BusContext *context)
>                                                       bus_pending_reply_expired,
>                                                       connections);
>   if (connections->pending_replies == NULL)
>-    goto failed_4;
>+    goto failed_5;
>   
>   if (!_dbus_loop_add_timeout (bus_context_get_loop (context),
>                                connections->expire_timeout))
>-    goto failed_5;
>+    goto failed_6;
>   
>   connections->refcount = 1;
>   connections->context = context;
>   
>   return connections;
> 
>- failed_5:
>+ failed_6:
>   bus_expire_list_free (connections->pending_replies);
>- failed_4:
>+ failed_5:
>   _dbus_timeout_unref (connections->expire_timeout);
>+ failed_4:
>+  _dbus_hash_table_unref (connections->completed_by_process);
>  failed_3:
>   _dbus_hash_table_unref (connections->completed_by_user);
>  failed_2:
>@@ -521,6 +594,7 @@ bus_connections_unref (BusConnections *connections)
>       _dbus_timeout_unref (connections->expire_timeout);
>       
>       _dbus_hash_table_unref (connections->completed_by_user);
>+      _dbus_hash_table_unref (connections->completed_by_process);
>       
>       dbus_free (connections);
> 
>@@ -1358,6 +1432,8 @@ bus_connection_complete (DBusConnection   *connection,
> {
>   BusConnectionData *d;
>   unsigned long uid;
>+  dbus_bool_t rollback_uid = FALSE;
>+  dbus_bool_t rollback_pid = FALSE;
>   
>   d = BUS_CONNECTION_DATA (connection);
>   _dbus_assert (d != NULL);
>@@ -1400,6 +1476,14 @@ bus_connection_complete (DBusConnection   *connection,
>       if (!adjust_connections_for_uid (d->connections,
>                                        uid, 1))
>         goto fail;
>+      rollback_uid = TRUE;
>+    }
>+
>+  if (d->pid > 0)
>+    {
>+      if (!adjust_connections_for_pid (d->connections, d->pid, 1))
>+        goto fail;
>+      rollback_pid = TRUE;
>     }
> 
>   /* Create and cache a string which holds information about the 
>@@ -1427,6 +1511,10 @@ bus_connection_complete (DBusConnection   *connection,
>   return TRUE;
> fail:
>   BUS_SET_OOM (error);
>+  if (rollback_uid)
>+    adjust_connections_for_uid (d->connections, uid, -1);
>+  if (rollback_pid)
>+    adjust_connections_for_pid (d->connections, d->pid, -1);
>   dbus_free (d->name);
>   d->name = NULL;
>   if (d->policy)
>@@ -1492,6 +1580,11 @@ bus_connections_check_limits (BusConnections  *connections,
>                               DBusError       *error)
> {
>   unsigned long uid;
>+  unsigned long pid;
>+  BusConnectionData *d;
>+
>+  d = BUS_CONNECTION_DATA (requesting_completion);
>+  _dbus_assert (d != NULL);
> 
>   if (connections->n_completed >=
>       bus_context_get_max_completed_connections (connections->context))
>@@ -1513,6 +1606,26 @@ bus_connections_check_limits (BusConnections  *connections,
>         }
>     }
>   
>+  /* bus_connections_check_limits() could be called several times on the same
>+   * connection. Make sure to be idempotent. */
>+  if (d->pid == 0 &&
>+      dbus_connection_get_unix_process_id (requesting_completion, &pid))
>+    {
>+      d->pid = pid;
>+    }
>+
>+  if (d->pid > 0)
>+    {
>+      if (get_connections_for_pid (connections, d->pid) >=
>+          bus_context_get_max_connections_per_process (connections->context))
>+        {
>+          dbus_set_error (error, DBUS_ERROR_LIMITS_EXCEEDED,
>+                          "The maximum number of active connections for PID %lu has been reached",
>+                          d->pid);
>+          return FALSE;
>+        }
>+    }
>+
>   return TRUE;
> }
> 
>-- 
>1.8.5.3
>

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