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package/x11r7/xserver_xorg-server: add upstream security fixes for CVE-2020-14360 / 25712

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Fixes the following security issues:

* CVE-2020-14360 / ZDI CAN 11572 XkbSetMap Out-Of-Bounds Access

  Insufficient checks on the lengths of the XkbSetMap request can lead to
  out of bounds memory accesses in the X server.

* CVE-2020-25712 / ZDI-CAN-11839 XkbSetDeviceInfo Heap-based Buffer Overflow

  Insufficient checks on input of the XkbSetDeviceInfo request can lead to a
  buffer overflow on the head in the X server.

For more details, see the advisory:
https://www.openwall.com/lists/oss-security/2020/12/01/3

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
This commit is contained in:
Peter Korsgaard 2020-12-01 18:49:03 +01:00
parent 692829d967
commit c773336463
2 changed files with 231 additions and 0 deletions
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100
package/x11r7/xserver_xorg-server/0007-Fix-XkbSetDeviceInfo-and-SetDeviceIndicators-heap-ov.patch Normal file
View File

@ -0,0 +1,100 @@
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>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
---
xkb/xkb.c | 26 +++++++++++++++++++++++---
1 file changed, 23 insertions(+), 3 deletions(-)
diff --git a/xkb/xkb.c b/xkb/xkb.c
index 8e016cd74..f54cc97f8 100644
--- a/xkb/xkb.c
+++ b/xkb/xkb.c
@@ -6536,7 +6536,9 @@ SetDeviceIndicators(char *wire,
unsigned changed,
int num,
int *status_rtrn,
- ClientPtr client, xkbExtensionDeviceNotify * ev)
+ ClientPtr client,
+ xkbExtensionDeviceNotify * ev,
+ xkbSetDeviceInfoReq * stuff)
{
xkbDeviceLedsWireDesc *ledWire;
int i;
@@ -6557,6 +6559,11 @@ 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);
@@ -6575,6 +6582,10 @@ 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;
@@ -6592,6 +6603,10 @@ 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;
@@ -6671,7 +6686,7 @@ _XkbSetDeviceInfoCheck(ClientPtr client, DeviceIntPtr dev,
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;
@@ -6683,7 +6698,11 @@ _XkbSetDeviceInfoCheck(ClientPtr client, DeviceIntPtr dev,
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;
@@ -6704,7 +6723,8 @@ _XkbSetDeviceInfoCheck(ClientPtr client, DeviceIntPtr dev,
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;
}
--
2.20.1

131
package/x11r7/xserver_xorg-server/0008-Check-SetMap-request-length-carefully.patch Normal file
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@ -0,0 +1,131 @@
From 446ff2d3177087b8173fa779fa5b77a2a128988b Mon Sep 17 00:00:00 2001
From: Matthieu Herrb <matthieu@herrb.eu>
Date: Thu, 12 Nov 2020 19:15:07 +0100
Subject: [PATCH] Check SetMap request length carefully.
Avoid out of bounds memory accesses on too short request.
ZDI-CAN 11572 / CVE-2020-14360
This vulnerability was discovered by:
Jan-Niklas Sohn working with Trend Micro Zero Day Initiative
Signed-off-by: Matthieu Herrb <matthieu@herrb.eu>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
---
xkb/xkb.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 92 insertions(+)
diff --git a/xkb/xkb.c b/xkb/xkb.c
index f54cc97f8..d056c698c 100644
--- a/xkb/xkb.c
+++ b/xkb/xkb.c
@@ -2382,6 +2382,93 @@ SetVirtualModMap(XkbSrvInfoPtr xkbi,
return (char *) wire;
}
+#define _add_check_len(new) \
+ if (len > UINT32_MAX - (new) || len > req_len - (new)) goto bad; \
+ else len += new
+
+/**
+ * Check the length of the SetMap request
+ */
+static int
+_XkbSetMapCheckLength(xkbSetMapReq *req)
+{
+ size_t len = sz_xkbSetMapReq, req_len = req->length << 2;
+ xkbKeyTypeWireDesc *keytype;
+ xkbSymMapWireDesc *symmap;
+ BOOL preserve;
+ int i, map_count, nSyms;
+
+ if (req_len < len)
+ goto bad;
+ /* types */
+ if (req->present & XkbKeyTypesMask) {
+ keytype = (xkbKeyTypeWireDesc *)(req + 1);
+ for (i = 0; i < req->nTypes; i++) {
+ _add_check_len(XkbPaddedSize(sz_xkbKeyTypeWireDesc));
+ if (req->flags & XkbSetMapResizeTypes) {
+ _add_check_len(keytype->nMapEntries
+ * sz_xkbKTSetMapEntryWireDesc);
+ preserve = keytype->preserve;
+ map_count = keytype->nMapEntries;
+ if (preserve) {
+ _add_check_len(map_count * sz_xkbModsWireDesc);
+ }
+ keytype += 1;
+ keytype = (xkbKeyTypeWireDesc *)
+ ((xkbKTSetMapEntryWireDesc *)keytype + map_count);
+ if (preserve)
+ keytype = (xkbKeyTypeWireDesc *)
+ ((xkbModsWireDesc *)keytype + map_count);
+ }
+ }
+ }
+ /* syms */
+ if (req->present & XkbKeySymsMask) {
+ symmap = (xkbSymMapWireDesc *)((char *)req + len);
+ for (i = 0; i < req->nKeySyms; i++) {
+ _add_check_len(sz_xkbSymMapWireDesc);
+ nSyms = symmap->nSyms;
+ _add_check_len(nSyms*sizeof(CARD32));
+ symmap += 1;
+ symmap = (xkbSymMapWireDesc *)((CARD32 *)symmap + nSyms);
+ }
+ }
+ /* actions */
+ if (req->present & XkbKeyActionsMask) {
+ _add_check_len(req->totalActs * sz_xkbActionWireDesc
+ + XkbPaddedSize(req->nKeyActs));
+ }
+ /* behaviours */
+ if (req->present & XkbKeyBehaviorsMask) {
+ _add_check_len(req->totalKeyBehaviors * sz_xkbBehaviorWireDesc);
+ }
+ /* vmods */
+ if (req->present & XkbVirtualModsMask) {
+ _add_check_len(XkbPaddedSize(Ones(req->virtualMods)));
+ }
+ /* explicit */
+ if (req->present & XkbExplicitComponentsMask) {
+ /* two bytes per non-zero explicit componen */
+ _add_check_len(XkbPaddedSize(req->totalKeyExplicit * sizeof(CARD16)));
+ }
+ /* modmap */
+ if (req->present & XkbModifierMapMask) {
+ /* two bytes per non-zero modmap component */
+ _add_check_len(XkbPaddedSize(req->totalModMapKeys * sizeof(CARD16)));
+ }
+ /* vmodmap */
+ if (req->present & XkbVirtualModMapMask) {
+ _add_check_len(req->totalVModMapKeys * sz_xkbVModMapWireDesc);
+ }
+ if (len == req_len)
+ return Success;
+bad:
+ ErrorF("[xkb] BOGUS LENGTH in SetMap: expected %ld got %ld\n",
+ len, req_len);
+ return BadLength;
+}
+
+
/**
* Check if the given request can be applied to the given device but don't
* actually do anything, except swap values when client->swapped and doswap are both true.
@@ -2642,6 +2729,11 @@ ProcXkbSetMap(ClientPtr client)
CHK_KBD_DEVICE(dev, stuff->deviceSpec, client, DixManageAccess);
CHK_MASK_LEGAL(0x01, stuff->present, XkbAllMapComponentsMask);
+ /* first verify the request length carefully */
+ rc = _XkbSetMapCheckLength(stuff);
+ if (rc != Success)
+ return rc;
+
tmp = (char *) &stuff[1];
/* Check if we can to the SetMap on the requested device. If this
--
2.20.1