diff options
Diffstat (limited to 'CVE-2017-10971.patch')
| -rw-r--r-- | CVE-2017-10971.patch | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/CVE-2017-10971.patch b/CVE-2017-10971.patch new file mode 100644 index 000000000000..2696033e58c2 --- /dev/null +++ b/CVE-2017-10971.patch @@ -0,0 +1,153 @@ +From 215f894965df5fb0bb45b107d84524e700d2073c Mon Sep 17 00:00:00 2001 +From: Michal Srb <msrb@suse.com> +Date: Wed, 24 May 2017 15:54:40 +0300 +Subject: dix: Disallow GenericEvent in SendEvent request. + +The SendEvent request holds xEvent which is exactly 32 bytes long, no more, +no less. Both ProcSendEvent and SProcSendEvent verify that the received data +exactly match the request size. However nothing stops the client from passing +in event with xEvent::type = GenericEvent and any value of +xGenericEvent::length. + +In the case of ProcSendEvent, the event will be eventually passed to +WriteEventsToClient which will see that it is Generic event and copy the +arbitrary length from the receive buffer (and possibly past it) and send it to +the other client. This allows clients to copy unitialized heap memory out of X +server or to crash it. + +In case of SProcSendEvent, it will attempt to swap the incoming event by +calling a swapping function from the EventSwapVector array. The swapped event +is written to target buffer, which in this case is local xEvent variable. The +xEvent variable is 32 bytes long, but the swapping functions for GenericEvents +expect that the target buffer has size matching the size of the source +GenericEvent. This allows clients to cause stack buffer overflows. + +Signed-off-by: Michal Srb <msrb@suse.com> +Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net> +Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net> + +diff --git a/dix/events.c b/dix/events.c +index 3e3a01e..d3a33ea 100644 +--- a/dix/events.c ++++ b/dix/events.c +@@ -5366,6 +5366,12 @@ ProcSendEvent(ClientPtr client) + client->errorValue = stuff->event.u.u.type; + return BadValue; + } ++ /* Generic events can have variable size, but SendEvent request holds ++ exactly 32B of event data. */ ++ if (stuff->event.u.u.type == GenericEvent) { ++ client->errorValue = stuff->event.u.u.type; ++ return BadValue; ++ } + if (stuff->event.u.u.type == ClientMessage && + stuff->event.u.u.detail != 8 && + stuff->event.u.u.detail != 16 && stuff->event.u.u.detail != 32) { +diff --git a/dix/swapreq.c b/dix/swapreq.c +index 719e9b8..6785059 100644 +--- a/dix/swapreq.c ++++ b/dix/swapreq.c +@@ -292,6 +292,13 @@ SProcSendEvent(ClientPtr client) + swapl(&stuff->destination); + swapl(&stuff->eventMask); + ++ /* Generic events can have variable size, but SendEvent request holds ++ exactly 32B of event data. */ ++ if (stuff->event.u.u.type == GenericEvent) { ++ client->errorValue = stuff->event.u.u.type; ++ return BadValue; ++ } ++ + /* Swap event */ + proc = EventSwapVector[stuff->event.u.u.type & 0177]; + if (!proc || proc == NotImplemented) /* no swapping proc; invalid event type? */ +-- +cgit v0.10.2 + +From 8caed4df36b1f802b4992edcfd282cbeeec35d9d Mon Sep 17 00:00:00 2001 +From: Michal Srb <msrb@suse.com> +Date: Wed, 24 May 2017 15:54:41 +0300 +Subject: Xi: Verify all events in ProcXSendExtensionEvent. + +The requirement is that events have type in range +EXTENSION_EVENT_BASE..lastEvent, but it was tested +only for first event of all. + +Signed-off-by: Michal Srb <msrb@suse.com> +Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net> +Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net> + +diff --git a/Xi/sendexev.c b/Xi/sendexev.c +index 1cf118a..5e63bfc 100644 +--- a/Xi/sendexev.c ++++ b/Xi/sendexev.c +@@ -117,7 +117,7 @@ SProcXSendExtensionEvent(ClientPtr client) + int + ProcXSendExtensionEvent(ClientPtr client) + { +- int ret; ++ int ret, i; + DeviceIntPtr dev; + xEvent *first; + XEventClass *list; +@@ -141,10 +141,12 @@ ProcXSendExtensionEvent(ClientPtr client) + /* The client's event type must be one defined by an extension. */ + + first = ((xEvent *) &stuff[1]); +- if (!((EXTENSION_EVENT_BASE <= first->u.u.type) && +- (first->u.u.type < lastEvent))) { +- client->errorValue = first->u.u.type; +- return BadValue; ++ for (i = 0; i < stuff->num_events; i++) { ++ if (!((EXTENSION_EVENT_BASE <= first[i].u.u.type) && ++ (first[i].u.u.type < lastEvent))) { ++ client->errorValue = first[i].u.u.type; ++ return BadValue; ++ } + } + + list = (XEventClass *) (first + stuff->num_events); +-- +cgit v0.10.2 + +From ba336b24052122b136486961c82deac76bbde455 Mon Sep 17 00:00:00 2001 +From: Michal Srb <msrb@suse.com> +Date: Wed, 24 May 2017 15:54:42 +0300 +Subject: Xi: Do not try to swap GenericEvent. + +The SProcXSendExtensionEvent must not attempt to swap GenericEvent because +it is assuming that the event has fixed size and gives the swapping function +xEvent-sized buffer. + +A GenericEvent would be later rejected by ProcXSendExtensionEvent anyway. + +Signed-off-by: Michal Srb <msrb@suse.com> +Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net> +Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net> + +diff --git a/Xi/sendexev.c b/Xi/sendexev.c +index 5e63bfc..5c2e0fc 100644 +--- a/Xi/sendexev.c ++++ b/Xi/sendexev.c +@@ -95,9 +95,17 @@ SProcXSendExtensionEvent(ClientPtr client) + + eventP = (xEvent *) &stuff[1]; + for (i = 0; i < stuff->num_events; i++, eventP++) { ++ if (eventP->u.u.type == GenericEvent) { ++ client->errorValue = eventP->u.u.type; ++ return BadValue; ++ } ++ + proc = EventSwapVector[eventP->u.u.type & 0177]; +- if (proc == NotImplemented) /* no swapping proc; invalid event type? */ ++ /* no swapping proc; invalid event type? */ ++ if (proc == NotImplemented) { ++ client->errorValue = eventP->u.u.type; + return BadValue; ++ } + (*proc) (eventP, &eventT); + *eventP = eventT; + } +-- +cgit v0.10.2 + |