Changeset 89947 in vbox for trunk/src/VBox/HostServices/SharedClipboard

Timestamp:

Jun 29, 2021 10:42:28 AM (4 years ago)

Author:

vboxsync

Message:

X11: Host Services: Shared Clipboard: improve error code path handling, bugref:10038.

This commit improves error code path handling for X11 part of host Shared Clipboard
service. In particular, it adjusts initialization calls to match to its de-init counterpart.
It also adds more resources release on error path. In addition, this commit limits number of
simmultaneous HGCM connections to ShCl host service in order to prevent potential host flooding.

Location:

trunk/src/VBox/HostServices/SharedClipboard

Files:

• VBoxSharedClipboardSvc-x11.cpp (modified) (6 diffs)
• VBoxSharedClipboardSvc.cpp (modified) (3 diffs)

trunk/src/VBox/HostServices/SharedClipboard/VBoxSharedClipboardSvc-x11.cpp

@@ -27 +27 @@
 #include <iprt/semaphore.h>
 #include <iprt/string.h>
+#include <iprt/asm.h>
 
 #include <VBox/GuestHost/SharedClipboard.h>
@@ -35 +36 @@
 #include "VBoxSharedClipboardSvc-internal.h"
 
+/* Number of currently extablished connections. */
+static volatile uint32_t g_cShClConnections;
 
 /*********************************************************************************************************************************
@@ -76 +79 @@
     int rc;
 
+    /* Check if maximum allowed connections count has reached. */
+    if (ASMAtomicIncU32(&g_cShClConnections) > VBOX_SHARED_CLIPBOARD_X11_CONNECTIONS_MAX)
+    {
+        ASMAtomicDecU32(&g_cShClConnections);
+        LogRel(("Shared Clipboard: maximum amount for client connections reached\n"));
+        return VERR_OUT_OF_RESOURCES;
+    }
+
     PSHCLCONTEXT pCtx = (PSHCLCONTEXT)RTMemAllocZ(sizeof(SHCLCONTEXT));
     if (pCtx)
@@ -96 +107 @@
                 RTCritSectDelete(&pCtx->CritSect);
         }
-        else
+
+        if (RT_FAILURE(rc))
+        {
+            pClient->State.pCtx = NULL;
             RTMemFree(pCtx);
+        }
     }
     else
         rc = VERR_NO_MEMORY;
+
+    if (RT_FAILURE(rc))
+    {
+        /* Restore active connections count. */
+        ASMAtomicDecU32(&g_cShClConnections);
+    }
 
     LogFlowFuncLeaveRC(rc);
@@ -141 +162 @@
 
     RTMemFree(pCtx);
+
+    /* Decrease active connections count. */
+    ASMAtomicDecU32(&g_cShClConnections);
 
     LogFlowFuncLeaveRC(rc);
@@ -253 +277 @@
     LogFlowFunc(("pCtx=%p, fFormats=%#x\n", pCtx, fFormats));
 
+    int rc = VINF_SUCCESS;
     PSHCLCLIENT pClient = pCtx->pClient;
     AssertPtr(pClient);
 
-    RTCritSectEnter(&pClient->CritSect);
-
-    /** @todo r=bird: BUGBUG: Revisit this   */
-    if (fFormats == VBOX_SHCL_FMT_NONE) /* No formats to report? Bail out early. */
-        return;
-
-    int rc = ShClSvcHostReportFormats(pCtx->pClient, fFormats);
-    RT_NOREF(rc);
-
-    RTCritSectLeave(&pClient->CritSect);
+    rc = RTCritSectEnter(&pClient->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        /** @todo r=bird: BUGBUG: Revisit this   */
+        if (fFormats != VBOX_SHCL_FMT_NONE) /* No formats to report? */
+        {
+            rc = ShClSvcHostReportFormats(pCtx->pClient, fFormats);
+        }
+
+        RTCritSectLeave(&pClient->CritSect);
+    }
 
     LogFlowFuncLeaveRC(rc);

trunk/src/VBox/HostServices/SharedClipboard/VBoxSharedClipboardSvc.cpp

@@ -1995 +1995 @@
     if (RT_SUCCESS(rc))
     {
+        /* Assign weak pointer to client map .*/
+        g_mapClients[u32ClientID] = pClient; /** @todo Handle OOM / collisions? */
+
         rc = ShClBackendConnect(pClient, ShClSvcGetHeadless());
         if (RT_SUCCESS(rc))
@@ -2014 +2017 @@
             if (RT_SUCCESS(rc))
             {
-                /* Assign weak pointer to client map .*/
-                g_mapClients[u32ClientID] = pClient; /** @todo Handle OOM / collisions? */
-
                 /* For now we ASSUME that the first client ever connected is in charge for
                  * communicating withe the service extension.
@@ -2025 +2025 @@
             }
         }
+
+        if (RT_FAILURE(rc))
+        {
+            shClSvcClientDestroy(pClient);
+        }
+
     }