diff --git a/Xi/chgdctl.c b/Xi/chgdctl.c
index d078aa248..b3ee867f0 100644
--- a/Xi/chgdctl.c
+++ b/Xi/chgdctl.c
@@ -78,7 +78,7 @@ SProcXChangeDeviceControl(ClientPtr client)
 
     REQUEST(xChangeDeviceControlReq);
     swaps(&stuff->length);
-    REQUEST_AT_LEAST_SIZE(xChangeDeviceControlReq);
+    REQUEST_AT_LEAST_EXTRA_SIZE(xChangeDeviceControlReq, sizeof(xDeviceCtl));
     swaps(&stuff->control);
     ctl = (xDeviceCtl *) &stuff[1];
     swaps(&ctl->control);
@@ -115,7 +115,7 @@ ProcXChangeDeviceControl(ClientPtr client)
     xDeviceEnableCtl *e;
 
     REQUEST(xChangeDeviceControlReq);
-    REQUEST_AT_LEAST_SIZE(xChangeDeviceControlReq);
+    REQUEST_AT_LEAST_EXTRA_SIZE(xChangeDeviceControlReq, sizeof(xDeviceCtl));
 
     len = stuff->length - bytes_to_int32(sizeof(xChangeDeviceControlReq));
     ret = dixLookupDevice(&dev, stuff->deviceid, client, DixManageAccess);
@@ -192,6 +192,10 @@ ProcXChangeDeviceControl(ClientPtr client)
         break;
     case DEVICE_ENABLE:
         e = (xDeviceEnableCtl *) &stuff[1];
+        if ((len != bytes_to_int32(sizeof(xDeviceEnableCtl)))) {
+            ret = BadLength;
+            goto out;
+        }
 
         if (IsXTestDevice(dev, NULL))
             status = !Success;
diff --git a/Xi/chgfctl.c b/Xi/chgfctl.c
index 6dcf60c66..224c2ba0a 100644
--- a/Xi/chgfctl.c
+++ b/Xi/chgfctl.c
@@ -467,6 +467,8 @@ ProcXChangeFeedbackControl(ClientPtr client)
         xStringFeedbackCtl *f = ((xStringFeedbackCtl *) &stuff[1]);
 
         if (client->swapped) {
+            if (len < bytes_to_int32(sizeof(xStringFeedbackCtl)))
+                return BadLength;
             swaps(&f->num_keysyms);
         }
         if (len !=
diff --git a/Xi/sendexev.c b/Xi/sendexev.c
index 3c213864b..183f88dae 100644
--- a/Xi/sendexev.c
+++ b/Xi/sendexev.c
@@ -135,6 +135,9 @@ ProcXSendExtensionEvent(ClientPtr client)
     if (ret != Success)
         return ret;
 
+    if (stuff->num_events == 0)
+        return ret;
+
     /* The client's event type must be one defined by an extension. */
 
     first = ((xEvent *) &stuff[1]);
diff --git a/Xi/xiallowev.c b/Xi/xiallowev.c
index ebef23344..ca263ef1f 100644
--- a/Xi/xiallowev.c
+++ b/Xi/xiallowev.c
@@ -48,6 +48,7 @@ int
 SProcXIAllowEvents(ClientPtr client)
 {
     REQUEST(xXIAllowEventsReq);
+    REQUEST_AT_LEAST_SIZE(xXIAllowEventsReq);
 
     swaps(&stuff->length);
     swaps(&stuff->deviceid);
@@ -55,6 +56,7 @@ SProcXIAllowEvents(ClientPtr client)
     if (stuff->length > 3) {
         xXI2_2AllowEventsReq *req_xi22 = (xXI2_2AllowEventsReq *) stuff;
 
+        REQUEST_AT_LEAST_SIZE(xXI2_2AllowEventsReq);
         swapl(&req_xi22->touchid);
         swapl(&req_xi22->grab_window);
     }
diff --git a/Xi/xichangecursor.c b/Xi/xichangecursor.c
index 7a1bb7a0d..8e6255b6e 100644
--- a/Xi/xichangecursor.c
+++ b/Xi/xichangecursor.c
@@ -57,11 +57,11 @@ int
 SProcXIChangeCursor(ClientPtr client)
 {
     REQUEST(xXIChangeCursorReq);
+    REQUEST_SIZE_MATCH(xXIChangeCursorReq);
     swaps(&stuff->length);
     swapl(&stuff->win);
     swapl(&stuff->cursor);
     swaps(&stuff->deviceid);
-    REQUEST_SIZE_MATCH(xXIChangeCursorReq);
     return (ProcXIChangeCursor(client));
 }
 
diff --git a/Xi/xichangehierarchy.c b/Xi/xichangehierarchy.c
index 9e36354d1..27324452d 100644
--- a/Xi/xichangehierarchy.c
+++ b/Xi/xichangehierarchy.c
@@ -411,7 +411,7 @@ int
 ProcXIChangeHierarchy(ClientPtr client)
 {
     xXIAnyHierarchyChangeInfo *any;
-    int required_len = sizeof(xXIChangeHierarchyReq);
+    size_t len;			/* length of data remaining in request */
     int rc = Success;
     int flags[MAXDEVICES] = { 0 };
 
@@ -421,21 +421,46 @@ ProcXIChangeHierarchy(ClientPtr client)
     if (!stuff->num_changes)
         return rc;
 
+    if (stuff->length > (INT_MAX >> 2))
+        return BadAlloc;
+    len = (stuff->length << 2) - sizeof(xXIAnyHierarchyChangeInfo);
+
     any = (xXIAnyHierarchyChangeInfo *) &stuff[1];
     while (stuff->num_changes--) {
+        if (len < sizeof(xXIAnyHierarchyChangeInfo)) {
+            rc = BadLength;
+            goto unwind;
+        }
+
         SWAPIF(swaps(&any->type));
         SWAPIF(swaps(&any->length));
 
-        required_len += any->length;
-        if ((stuff->length * 4) < required_len)
+        if ((any->length > (INT_MAX >> 2)) || (len < (any->length << 2)))
             return BadLength;
 
+#define CHANGE_SIZE_MATCH(type) \
+    do { \
+        if ((len < sizeof(type)) || (any->length != (sizeof(type) >> 2))) { \
+            rc = BadLength; \
+            goto unwind; \
+        } \
+    } while(0)
+
         switch (any->type) {
         case XIAddMaster:
         {
             xXIAddMasterInfo *c = (xXIAddMasterInfo *) any;
 
+            /* Variable length, due to appended name string */
+            if (len < sizeof(xXIAddMasterInfo)) {
+                rc = BadLength;
+                goto unwind;
+            }
             SWAPIF(swaps(&c->name_len));
+            if (c->name_len > (len - sizeof(xXIAddMasterInfo))) {
+                rc = BadLength;
+                goto unwind;
+            }
 
             rc = add_master(client, c, flags);
             if (rc != Success)
@@ -446,6 +471,7 @@ ProcXIChangeHierarchy(ClientPtr client)
         {
             xXIRemoveMasterInfo *r = (xXIRemoveMasterInfo *) any;
 
+            CHANGE_SIZE_MATCH(xXIRemoveMasterInfo);
             rc = remove_master(client, r, flags);
             if (rc != Success)
                 goto unwind;
@@ -455,6 +481,7 @@ ProcXIChangeHierarchy(ClientPtr client)
         {
             xXIDetachSlaveInfo *c = (xXIDetachSlaveInfo *) any;
 
+            CHANGE_SIZE_MATCH(xXIDetachSlaveInfo);
             rc = detach_slave(client, c, flags);
             if (rc != Success)
                 goto unwind;
@@ -464,6 +491,7 @@ ProcXIChangeHierarchy(ClientPtr client)
         {
             xXIAttachSlaveInfo *c = (xXIAttachSlaveInfo *) any;
 
+            CHANGE_SIZE_MATCH(xXIAttachSlaveInfo);
             rc = attach_slave(client, c, flags);
             if (rc != Success)
                 goto unwind;
@@ -471,6 +499,7 @@ ProcXIChangeHierarchy(ClientPtr client)
             break;
         }
 
+        len -= any->length * 4;
         any = (xXIAnyHierarchyChangeInfo *) ((char *) any + any->length * 4);
     }
 
diff --git a/Xi/xigetclientpointer.c b/Xi/xigetclientpointer.c
index 3c90d588d..306dd396b 100644
--- a/Xi/xigetclientpointer.c
+++ b/Xi/xigetclientpointer.c
@@ -50,6 +50,7 @@ int
 SProcXIGetClientPointer(ClientPtr client)
 {
     REQUEST(xXIGetClientPointerReq);
+    REQUEST_SIZE_MATCH(xXIGetClientPointerReq);
 
     swaps(&stuff->length);
     swapl(&stuff->win);
diff --git a/Xi/xigrabdev.c b/Xi/xigrabdev.c
index 63d95bc1c..e2a2ae333 100644
--- a/Xi/xigrabdev.c
+++ b/Xi/xigrabdev.c
@@ -47,6 +47,11 @@ int
 SProcXIGrabDevice(ClientPtr client)
 {
     REQUEST(xXIGrabDeviceReq);
+    /*
+     * Check here for at least the length of the struct we swap, then
+     * let ProcXIGrabDevice check the full size after we swap mask_len.
+     */
+    REQUEST_AT_LEAST_SIZE(xXIGrabDeviceReq);
 
     swaps(&stuff->length);
     swaps(&stuff->deviceid);
@@ -71,7 +76,7 @@ ProcXIGrabDevice(ClientPtr client)
     unsigned int pointer_mode;
 
     REQUEST(xXIGrabDeviceReq);
-    REQUEST_AT_LEAST_SIZE(xXIGrabDeviceReq);
+    REQUEST_FIXED_SIZE(xXIGrabDeviceReq, ((size_t) stuff->mask_len) * 4);
 
     ret = dixLookupDevice(&dev, stuff->deviceid, client, DixGrabAccess);
     if (ret != Success)
@@ -131,6 +136,7 @@ int
 SProcXIUngrabDevice(ClientPtr client)
 {
     REQUEST(xXIUngrabDeviceReq);
+    REQUEST_SIZE_MATCH(xXIUngrabDeviceReq);
 
     swaps(&stuff->length);
     swaps(&stuff->deviceid);
@@ -148,6 +154,7 @@ ProcXIUngrabDevice(ClientPtr client)
     TimeStamp time;
 
     REQUEST(xXIUngrabDeviceReq);
+    REQUEST_SIZE_MATCH(xXIUngrabDeviceReq);
 
     ret = dixLookupDevice(&dev, stuff->deviceid, client, DixGetAttrAccess);
     if (ret != Success)
diff --git a/Xi/xipassivegrab.c b/Xi/xipassivegrab.c
index 700622d38..9241ffdea 100644
--- a/Xi/xipassivegrab.c
+++ b/Xi/xipassivegrab.c
@@ -53,6 +53,7 @@ SProcXIPassiveGrabDevice(ClientPtr client)
     uint32_t *mods;
 
     REQUEST(xXIPassiveGrabDeviceReq);
+    REQUEST_AT_LEAST_SIZE(xXIPassiveGrabDeviceReq);
 
     swaps(&stuff->length);
     swaps(&stuff->deviceid);
@@ -63,6 +64,8 @@ SProcXIPassiveGrabDevice(ClientPtr client)
     swaps(&stuff->mask_len);
     swaps(&stuff->num_modifiers);
 
+    REQUEST_FIXED_SIZE(xXIPassiveGrabDeviceReq,
+        ((uint32_t) stuff->mask_len + stuff->num_modifiers) *4);
     mods = (uint32_t *) &stuff[1] + stuff->mask_len;
 
     for (i = 0; i < stuff->num_modifiers; i++, mods++) {
@@ -92,7 +95,8 @@ ProcXIPassiveGrabDevice(ClientPtr client)
     int mask_len;
 
     REQUEST(xXIPassiveGrabDeviceReq);
-    REQUEST_AT_LEAST_SIZE(xXIPassiveGrabDeviceReq);
+    REQUEST_FIXED_SIZE(xXIPassiveGrabDeviceReq,
+        ((uint32_t) stuff->mask_len + stuff->num_modifiers) * 4);
 
     if (stuff->deviceid == XIAllDevices)
         dev = inputInfo.all_devices;
@@ -252,6 +256,7 @@ SProcXIPassiveUngrabDevice(ClientPtr client)
     uint32_t *modifiers;
 
     REQUEST(xXIPassiveUngrabDeviceReq);
+    REQUEST_AT_LEAST_SIZE(xXIPassiveUngrabDeviceReq);
 
     swaps(&stuff->length);
     swapl(&stuff->grab_window);
@@ -259,6 +264,8 @@ SProcXIPassiveUngrabDevice(ClientPtr client)
     swapl(&stuff->detail);
     swaps(&stuff->num_modifiers);
 
+    REQUEST_FIXED_SIZE(xXIPassiveUngrabDeviceReq,
+                       ((uint32_t) stuff->num_modifiers) << 2);
     modifiers = (uint32_t *) &stuff[1];
 
     for (i = 0; i < stuff->num_modifiers; i++, modifiers++)
@@ -277,7 +284,8 @@ ProcXIPassiveUngrabDevice(ClientPtr client)
     int i, rc;
 
     REQUEST(xXIPassiveUngrabDeviceReq);
-    REQUEST_AT_LEAST_SIZE(xXIPassiveUngrabDeviceReq);
+    REQUEST_FIXED_SIZE(xXIPassiveUngrabDeviceReq,
+                       ((uint32_t) stuff->num_modifiers) << 2);
 
     if (stuff->deviceid == XIAllDevices)
         dev = inputInfo.all_devices;
diff --git a/Xi/xiproperty.c b/Xi/xiproperty.c
index 463607d33..8e8e4b061 100644
--- a/Xi/xiproperty.c
+++ b/Xi/xiproperty.c
@@ -1013,10 +1013,9 @@ int
 SProcXListDeviceProperties(ClientPtr client)
 {
     REQUEST(xListDevicePropertiesReq);
+    REQUEST_SIZE_MATCH(xListDevicePropertiesReq);
 
     swaps(&stuff->length);
-
-    REQUEST_SIZE_MATCH(xListDevicePropertiesReq);
     return (ProcXListDeviceProperties(client));
 }
 
@@ -1037,10 +1036,10 @@ int
 SProcXDeleteDeviceProperty(ClientPtr client)
 {
     REQUEST(xDeleteDevicePropertyReq);
+    REQUEST_SIZE_MATCH(xDeleteDevicePropertyReq);
 
     swaps(&stuff->length);
     swapl(&stuff->property);
-    REQUEST_SIZE_MATCH(xDeleteDevicePropertyReq);
     return (ProcXDeleteDeviceProperty(client));
 }
 
@@ -1048,13 +1047,13 @@ int
 SProcXGetDeviceProperty(ClientPtr client)
 {
     REQUEST(xGetDevicePropertyReq);
+    REQUEST_SIZE_MATCH(xGetDevicePropertyReq);
 
     swaps(&stuff->length);
     swapl(&stuff->property);
     swapl(&stuff->type);
     swapl(&stuff->longOffset);
     swapl(&stuff->longLength);
-    REQUEST_SIZE_MATCH(xGetDevicePropertyReq);
     return (ProcXGetDeviceProperty(client));
 }
 
@@ -1253,11 +1252,10 @@ int
 SProcXIListProperties(ClientPtr client)
 {
     REQUEST(xXIListPropertiesReq);
+    REQUEST_SIZE_MATCH(xXIListPropertiesReq);
 
     swaps(&stuff->length);
     swaps(&stuff->deviceid);
-
-    REQUEST_SIZE_MATCH(xXIListPropertiesReq);
     return (ProcXIListProperties(client));
 }
 
@@ -1279,11 +1277,11 @@ int
 SProcXIDeleteProperty(ClientPtr client)
 {
     REQUEST(xXIDeletePropertyReq);
+    REQUEST_SIZE_MATCH(xXIDeletePropertyReq);
 
     swaps(&stuff->length);
     swaps(&stuff->deviceid);
     swapl(&stuff->property);
-    REQUEST_SIZE_MATCH(xXIDeletePropertyReq);
     return (ProcXIDeleteProperty(client));
 }
 
@@ -1291,6 +1289,7 @@ int
 SProcXIGetProperty(ClientPtr client)
 {
     REQUEST(xXIGetPropertyReq);
+    REQUEST_SIZE_MATCH(xXIGetPropertyReq);
 
     swaps(&stuff->length);
     swaps(&stuff->deviceid);
@@ -1298,7 +1297,6 @@ SProcXIGetProperty(ClientPtr client)
     swapl(&stuff->type);
     swapl(&stuff->offset);
     swapl(&stuff->len);
-    REQUEST_SIZE_MATCH(xXIGetPropertyReq);
     return (ProcXIGetProperty(client));
 }
 
diff --git a/Xi/xiquerydevice.c b/Xi/xiquerydevice.c
index 4e544f0f5..67a9a4f3f 100644
--- a/Xi/xiquerydevice.c
+++ b/Xi/xiquerydevice.c
@@ -54,6 +54,7 @@ int
 SProcXIQueryDevice(ClientPtr client)
 {
     REQUEST(xXIQueryDeviceReq);
+    REQUEST_SIZE_MATCH(xXIQueryDeviceReq);
 
     swaps(&stuff->length);
     swaps(&stuff->deviceid);
diff --git a/Xi/xiquerypointer.c b/Xi/xiquerypointer.c
index e9bdd428d..7ec0c851d 100644
--- a/Xi/xiquerypointer.c
+++ b/Xi/xiquerypointer.c
@@ -63,6 +63,8 @@ int
 SProcXIQueryPointer(ClientPtr client)
 {
     REQUEST(xXIQueryPointerReq);
+    REQUEST_SIZE_MATCH(xXIQueryPointerReq);
+
     swaps(&stuff->length);
     swaps(&stuff->deviceid);
     swapl(&stuff->win);
diff --git a/Xi/xiselectev.c b/Xi/xiselectev.c
index 45a996e4c..168579f5b 100644
--- a/Xi/xiselectev.c
+++ b/Xi/xiselectev.c
@@ -114,6 +114,7 @@ int
 SProcXISelectEvents(ClientPtr client)
 {
     int i;
+    int len;
     xXIEventMask *evmask;
 
     REQUEST(xXISelectEventsReq);
@@ -122,10 +123,17 @@ SProcXISelectEvents(ClientPtr client)
     swapl(&stuff->win);
     swaps(&stuff->num_masks);
 
+    len = stuff->length - bytes_to_int32(sizeof(xXISelectEventsReq));
     evmask = (xXIEventMask *) &stuff[1];
     for (i = 0; i < stuff->num_masks; i++) {
+        if (len < bytes_to_int32(sizeof(xXIEventMask)))
+            return BadLength;
+        len -= bytes_to_int32(sizeof(xXIEventMask));
         swaps(&evmask->deviceid);
         swaps(&evmask->mask_len);
+        if (len < evmask->mask_len)
+            return BadLength;
+        len -= evmask->mask_len;
         evmask =
             (xXIEventMask *) (((char *) &evmask[1]) + evmask->mask_len * 4);
     }
diff --git a/Xi/xisetclientpointer.c b/Xi/xisetclientpointer.c
index 38ff51e86..24d4a5379 100644
--- a/Xi/xisetclientpointer.c
+++ b/Xi/xisetclientpointer.c
@@ -51,10 +51,11 @@ int
 SProcXISetClientPointer(ClientPtr client)
 {
     REQUEST(xXISetClientPointerReq);
+    REQUEST_SIZE_MATCH(xXISetClientPointerReq);
+
     swaps(&stuff->length);
     swapl(&stuff->win);
     swaps(&stuff->deviceid);
-    REQUEST_SIZE_MATCH(xXISetClientPointerReq);
     return (ProcXISetClientPointer(client));
 }
 
diff --git a/Xi/xisetdevfocus.c b/Xi/xisetdevfocus.c
index 372ec248a..96a9a16e4 100644
--- a/Xi/xisetdevfocus.c
+++ b/Xi/xisetdevfocus.c
@@ -44,6 +44,8 @@ int
 SProcXISetFocus(ClientPtr client)
 {
     REQUEST(xXISetFocusReq);
+    REQUEST_AT_LEAST_SIZE(xXISetFocusReq);
+
     swaps(&stuff->length);
     swaps(&stuff->deviceid);
     swapl(&stuff->focus);
@@ -56,6 +58,8 @@ int
 SProcXIGetFocus(ClientPtr client)
 {
     REQUEST(xXIGetFocusReq);
+    REQUEST_AT_LEAST_SIZE(xXIGetFocusReq);
+
     swaps(&stuff->length);
     swaps(&stuff->deviceid);
 
diff --git a/Xi/xiwarppointer.c b/Xi/xiwarppointer.c
index 3f051f759..780758a9e 100644
--- a/Xi/xiwarppointer.c
+++ b/Xi/xiwarppointer.c
@@ -56,6 +56,8 @@ int
 SProcXIWarpPointer(ClientPtr client)
 {
     REQUEST(xXIWarpPointerReq);
+    REQUEST_SIZE_MATCH(xXIWarpPointerReq);
+
     swaps(&stuff->length);
     swapl(&stuff->src_win);
     swapl(&stuff->dst_win);
diff --git a/include/dix.h b/include/dix.h
index e0c6ed84f..21176a8c3 100644
--- a/include/dix.h
+++ b/include/dix.h
@@ -74,6 +74,10 @@ SOFTWARE.
     if ((sizeof(req) >> 2) > client->req_len )\
          return(BadLength)
 
+#define REQUEST_AT_LEAST_EXTRA_SIZE(req, extra)  \
+    if (((sizeof(req) + ((uint64_t) extra)) >> 2) > client->req_len ) \
+         return(BadLength)
+
 #define REQUEST_FIXED_SIZE(req, n)\
     if (((sizeof(req) >> 2) > client->req_len) || \
         ((n >> 2) >= client->req_len) || \