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From 87c64fc5b0db9f62f4e361444f4b60501ebf67b9 Mon Sep 17 00:00:00 2001
From: Matthieu Herrb <matthieu@herrb.eu>
Date: Sun, 11 Oct 2020 17:05:09 +0200
Subject: [PATCH] Fix XkbSetDeviceInfo() and SetDeviceIndicators() heap
overflows
ZDI-CAN 11389 / CVE-2020-25712
This vulnerability was discovered by:
Jan-Niklas Sohn working with Trend Micro Zero Day Initiative
Signed-off-by: Matthieu Herrb <matthieu@herrb.eu>
Upstream-Status: Backport
https://gitlab.freedesktop.org/xorg/xserver/-/commit/87c64fc5b0db9f62f4e361444f4b60501ebf67b9
CVE: CVE-2020-25712
Signed-off-by: Armin Kuster <akuster@mvista.com>
---
xkb/xkb.c | 26 +++++++++++++++++++++++---
1 file changed, 23 insertions(+), 3 deletions(-)
Index: xorg-server-1.20.8/xkb/xkb.c
===================================================================
--- xorg-server-1.20.8.orig/xkb/xkb.c
+++ xorg-server-1.20.8/xkb/xkb.c
@@ -6625,7 +6625,9 @@ SetDeviceIndicators(char *wire,
unsigned changed,
int num,
int *status_rtrn,
- ClientPtr client, xkbExtensionDeviceNotify * ev)
+ ClientPtr client,
+ xkbExtensionDeviceNotify * ev,
+ xkbSetDeviceInfoReq * stuff)
{
xkbDeviceLedsWireDesc *ledWire;
int i;
@@ -6646,6 +6648,11 @@ SetDeviceIndicators(char *wire,
xkbIndicatorMapWireDesc *mapWire;
XkbSrvLedInfoPtr sli;
+ if (!_XkbCheckRequestBounds(client, stuff, ledWire, ledWire + 1)) {
+ *status_rtrn = BadLength;
+ return (char *) ledWire;
+ }
+
namec = mapc = statec = 0;
sli = XkbFindSrvLedInfo(dev, ledWire->ledClass, ledWire->ledID,
XkbXI_IndicatorMapsMask);
@@ -6664,6 +6671,10 @@ SetDeviceIndicators(char *wire,
memset((char *) sli->names, 0, XkbNumIndicators * sizeof(Atom));
for (n = 0, bit = 1; n < XkbNumIndicators; n++, bit <<= 1) {
if (ledWire->namesPresent & bit) {
+ if (!_XkbCheckRequestBounds(client, stuff, atomWire, atomWire + 1)) {
+ *status_rtrn = BadLength;
+ return (char *) atomWire;
+ }
sli->names[n] = (Atom) *atomWire;
if (sli->names[n] == None)
ledWire->namesPresent &= ~bit;
@@ -6681,6 +6692,10 @@ SetDeviceIndicators(char *wire,
if (ledWire->mapsPresent) {
for (n = 0, bit = 1; n < XkbNumIndicators; n++, bit <<= 1) {
if (ledWire->mapsPresent & bit) {
+ if (!_XkbCheckRequestBounds(client, stuff, mapWire, mapWire + 1)) {
+ *status_rtrn = BadLength;
+ return (char *) mapWire;
+ }
sli->maps[n].flags = mapWire->flags;
sli->maps[n].which_groups = mapWire->whichGroups;
sli->maps[n].groups = mapWire->groups;
@@ -6760,7 +6775,7 @@ _XkbSetDeviceInfoCheck(ClientPtr client,
ed.deviceID = dev->id;
wire = (char *) &stuff[1];
if (stuff->change & XkbXI_ButtonActionsMask) {
- int nBtns, sz, i;
+ int nBtns, sz, i;
XkbAction *acts;
DeviceIntPtr kbd;
@@ -6772,7 +6787,11 @@ _XkbSetDeviceInfoCheck(ClientPtr client,
return BadAlloc;
dev->button->xkb_acts = acts;
}
+ if (stuff->firstBtn + stuff->nBtns > nBtns)
+ return BadValue;
sz = stuff->nBtns * SIZEOF(xkbActionWireDesc);
+ if (!_XkbCheckRequestBounds(client, stuff, wire, (char *) wire + sz))
+ return BadLength;
memcpy((char *) &acts[stuff->firstBtn], (char *) wire, sz);
wire += sz;
ed.reason |= XkbXI_ButtonActionsMask;
@@ -6793,7 +6812,8 @@ _XkbSetDeviceInfoCheck(ClientPtr client,
int status = Success;
wire = SetDeviceIndicators(wire, dev, stuff->change,
- stuff->nDeviceLedFBs, &status, client, &ed);
+ stuff->nDeviceLedFBs, &status, client, &ed,
+ stuff);
if (status != Success)
return status;
}
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