From 19a9cd607de73947fcfb104682f203ffe4e1f4e5 Mon Sep 17 00:00:00 2001
From: Tobias Stoeckmann <tobias@stoeckmann.org>
Date: Sun, 25 Sep 2016 22:31:34 +0200
Subject: [PATCH:libXi] Properly validate server responses.
By validating length fields from server responses, out of boundary
accesses and endless loops can be mitigated.
Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>
Reviewed-by: Matthieu Herrb <matthieu@herrb.eu>
---
src/XGMotion.c | 3 ++-
src/XGetBMap.c | 3 ++-
src/XGetDCtl.c | 6 ++++--
src/XGetFCtl.c | 7 ++++++-
src/XGetKMap.c | 14 +++++++++++---
src/XGetMMap.c | 11 +++++++++--
src/XIQueryDevice.c | 36 ++++++++++++++++++++++++++++++++++--
src/XListDev.c | 21 +++++++++++++++------
src/XOpenDev.c | 13 ++++++++++---
src/XQueryDv.c | 8 ++++++--
10 files changed, 99 insertions(+), 23 deletions(-)
diff --git a/src/XGMotion.c b/src/XGMotion.c
index 7785843..9433e29 100644
--- a/src/XGMotion.c
+++ b/src/XGMotion.c
@@ -114,7 +114,8 @@ XGetDeviceMotionEvents(
}
/* rep.axes is a CARD8, so assume max number of axes for bounds check */
if (rep.nEvents <
- (INT_MAX / (sizeof(XDeviceTimeCoord) + (UCHAR_MAX * sizeof(int))))) {
+ (INT_MAX / (sizeof(XDeviceTimeCoord) + (UCHAR_MAX * sizeof(int)))) &&
size_t bsize = rep.nEvents *
(sizeof(XDeviceTimeCoord) + (rep.axes * sizeof(int)));
bufp = Xmalloc(bsize);
diff --git a/src/XGetBMap.c b/src/XGetBMap.c
index 002daba..13bb8c6 100644
--- a/src/XGetBMap.c
+++ b/src/XGetBMap.c
@@ -92,7 +92,8 @@ XGetDeviceButtonMapping(
status = _XReply(dpy, (xReply *) & rep, 0, xFalse);
if (status == 1) {
- if (rep.length <= (sizeof(mapping) >> 2)) {
+ if (rep.length <= (sizeof(mapping) >> 2) &&
+ rep.nElts <= (rep.length << 2)) {
unsigned long nbytes = rep.length << 2;
_XRead(dpy, (char *)mapping, nbytes);
diff --git a/src/XGetDCtl.c b/src/XGetDCtl.c
index c5d3b53..7f6b396 100644
--- a/src/XGetDCtl.c
+++ b/src/XGetDCtl.c
@@ -93,7 +93,8 @@ XGetDeviceControl(
if (rep.length > 0) {
unsigned long nbytes;
size_t size = 0;
- if (rep.length < (INT_MAX >> 2)) {
+ if (rep.length < (INT_MAX >> 2) &&
+ (rep.length << 2) >= sizeof(xDeviceState)) {
nbytes = (unsigned long) rep.length << 2;
d = Xmalloc(nbytes);
}
@@ -117,7 +118,8 @@ XGetDeviceControl(
size_t val_size;
r = (xDeviceResolutionState *) d;
- if (r->num_valuators >= (INT_MAX / (3 * sizeof(int))))
+ if (sizeof(xDeviceResolutionState) > nbytes ||
+ r->num_valuators >= (INT_MAX / (3 * sizeof(int))))
goto out;
val_size = 3 * sizeof(int) * r->num_valuators;
if ((sizeof(xDeviceResolutionState) + val_size) > nbytes)
diff --git a/src/XGetFCtl.c b/src/XGetFCtl.c
index 7fd6d0e..82dcc64 100644
--- a/src/XGetFCtl.c
+++ b/src/XGetFCtl.c
@@ -73,6 +73,7 @@ XGetFeedbackControl(
XFeedbackState *Sav = NULL;
xFeedbackState *f = NULL;
xFeedbackState *sav = NULL;
+ char *end = NULL;
xGetFeedbackControlReq *req;
xGetFeedbackControlReply rep;
XExtDisplayInfo *info = XInput_find_display(dpy);
@@ -105,10 +106,12 @@ XGetFeedbackControl(
goto out;
}
sav = f;
+ end = (char *)f + nbytes;
_XRead(dpy, (char *)f, nbytes);
for (i = 0; i < *num_feedbacks; i++) {
- if (f->length > nbytes)
+ if ((char *)f + sizeof(*f) > end ||
+ f->length == 0 || f->length > nbytes)
goto out;
nbytes -= f->length;
@@ -125,6 +128,8 @@ XGetFeedbackControl(
case StringFeedbackClass:
{
xStringFeedbackState *strf = (xStringFeedbackState *) f;
+ if ((char *)f + sizeof(*strf) > end)
+ goto out;
size += sizeof(XStringFeedbackState) +
(strf->num_syms_supported * sizeof(KeySym));
}
diff --git a/src/XGetKMap.c b/src/XGetKMap.c
index 0540ce4..008a72b 100644
--- a/src/XGetKMap.c
+++ b/src/XGetKMap.c
@@ -54,6 +54,7 @@ SOFTWARE.
#include <config.h>
#endif
+#include <limits.h>
#include <X11/extensions/XI.h>
#include <X11/extensions/XIproto.h>
#include <X11/Xlibint.h>
@@ -93,9 +94,16 @@ XGetDeviceKeyMapping(register Display * dpy, XDevice * dev,
return (KeySym *) NULL;
}
if (rep.length > 0) {
- *syms_per_code = rep.keySymsPerKeyCode;
- nbytes = (long)rep.length << 2;
- mapping = (KeySym *) Xmalloc((unsigned)nbytes);
+ if (rep.length < INT_MAX >> 2 &&
+ rep.length == rep.keySymsPerKeyCode * keycount) {
+ *syms_per_code = rep.keySymsPerKeyCode;
+ nbytes = (long)rep.length << 2;
+ mapping = (KeySym *) Xmalloc((unsigned)nbytes);
+ } else {
+ *syms_per_code = 0;
+ nbytes = 0;
+ mapping = NULL;
+ }
if (mapping)
_XRead(dpy, (char *)mapping, nbytes);
else
diff --git a/src/XGetMMap.c b/src/XGetMMap.c
index 246698c..33c114f 100644
--- a/src/XGetMMap.c
+++ b/src/XGetMMap.c
@@ -53,6 +53,7 @@ SOFTWARE.
#include <config.h>
#endif
+#include <limits.h>
#include <X11/extensions/XI.h>
#include <X11/extensions/XIproto.h>
#include <X11/Xlibint.h>
@@ -85,8 +86,14 @@ XGetDeviceModifierMapping(
SyncHandle();
return (XModifierKeymap *) NULL;
}
- nbytes = (unsigned long)rep.length << 2;
- res = (XModifierKeymap *) Xmalloc(sizeof(XModifierKeymap));
+ if (rep.length < (INT_MAX >> 2) &&
+ rep.numKeyPerModifier == rep.length >> 1) {
+ nbytes = (unsigned long)rep.length << 2;
+ res = (XModifierKeymap *) Xmalloc(sizeof(XModifierKeymap));
+ } else {
+ nbytes = 0;
+ res = NULL;
+ }
if (res) {
res->modifiermap = (KeyCode *) Xmalloc(nbytes);
if (res->modifiermap)
diff --git a/src/XIQueryDevice.c b/src/XIQueryDevice.c
index fb8504f..a457cd6 100644
@@ -26,6 +26,7 @@
#include <config.h>
#endif
+#include <limits.h>
#include <stdint.h>
#include <X11/Xlibint.h>
#include <X11/extensions/XI2proto.h>
@@ -43,6 +44,7 @@ XIQueryDevice(Display *dpy, int deviceid, int *ndevices_return)
xXIQueryDeviceReq *req;
xXIQueryDeviceReply reply;
char *ptr;
+ char *end;
int i;
char *buf;
@@ -60,14 +62,24 @@ XIQueryDevice(Display *dpy, int deviceid, int *ndevices_return)
if (!_XReply(dpy, (xReply*) &reply, 0, xFalse))
goto error;
- *ndevices_return = reply.num_devices;
- info = Xmalloc((reply.num_devices + 1) * sizeof(XIDeviceInfo));
+ if (reply.length < INT_MAX / 4)
+ {
+ *ndevices_return = reply.num_devices;
+ info = Xmalloc((reply.num_devices + 1) * sizeof(XIDeviceInfo));
+ }
+ else
+ {
+ *ndevices_return = 0;
+ info = NULL;
+ }
+
if (!info)
goto error;
buf = Xmalloc(reply.length * 4);
_XRead(dpy, buf, reply.length * 4);
ptr = buf;
+ end = buf + reply.length * 4;
/* info is a null-terminated array */
info[reply.num_devices].name = NULL;
@@ -79,6 +91,9 @@ XIQueryDevice(Display *dpy, int deviceid, int *ndevices_return)
XIDeviceInfo *lib = &info[i];
xXIDeviceInfo *wire = (xXIDeviceInfo*)ptr;
+ if (ptr + sizeof(xXIDeviceInfo) > end)
+ goto error_loop;
+
lib->deviceid = wire->deviceid;
lib->use = wire->use;
lib->attachment = wire->attachment;
@@ -87,12 +102,23 @@ XIQueryDevice(Display *dpy, int deviceid, int *ndevices_return)
ptr += sizeof(xXIDeviceInfo);
+ if (ptr + wire->name_len > end)
+ goto error_loop;
+
lib->name = Xcalloc(wire->name_len + 1, 1);
+ if (lib->name == NULL)
+ goto error_loop;
strncpy(lib->name, ptr, wire->name_len);
+ lib->name[wire->name_len] = '\0';
ptr += ((wire->name_len + 3)/4) * 4;
sz = size_classes((xXIAnyInfo*)ptr, nclasses);
lib->classes = Xmalloc(sz);
+ if (lib->classes == NULL)
+ {
+ Xfree(lib->name);
+ goto error_loop;
+ }
ptr += copy_classes(lib, (xXIAnyInfo*)ptr, &nclasses);
/* We skip over unused classes */
lib->num_classes = nclasses;
@@ -103,6 +129,12 @@ XIQueryDevice(Display *dpy, int deviceid, int *ndevices_return)
SyncHandle();
return info;
+error_loop:
+ while (--i >= 0)
+ {
+ Xfree(info[i].name);
+ Xfree(info[i].classes);
+ }
error:
UnlockDisplay(dpy);
error_unlocked:
diff --git a/src/XListDev.c b/src/XListDev.c
index b85ff3c..f850cd0 100644
--- a/src/XListDev.c
+++ b/src/XListDev.c
@@ -74,7 +74,7 @@ static int pad_to_xid(int base_size)
}
static size_t
-SizeClassInfo(xAnyClassPtr *any, int num_classes)
+SizeClassInfo(xAnyClassPtr *any, size_t len, int num_classes)
{
int size = 0;
int j;
@@ -90,6 +90,8 @@ SizeClassInfo(xAnyClassPtr *any, int num_classes)
{
xValuatorInfoPtr v;
+ if (len < sizeof(v))
+ return 0;
v = (xValuatorInfoPtr) *any;
size += pad_to_xid(sizeof(XValuatorInfo) +
(v->num_axes * sizeof(XAxisInfo)));
@@ -98,6 +100,8 @@ SizeClassInfo(xAnyClassPtr *any, int num_classes)
default:
break;
}
+ if ((*any)->length > len)
+ return 0;
*any = (xAnyClassPtr) ((char *)(*any) + (*any)->length);
}
@@ -170,7 +174,7 @@ XListInputDevices(
register Display *dpy,
int *ndevices)
{
- size_t size;
+ size_t s, size;
xListInputDevicesReq *req;
xListInputDevicesReply rep;
xDeviceInfo *list, *slist = NULL;
@@ -178,6 +182,7 @@ XListInputDevices(
XDeviceInfo *clist = NULL;
xAnyClassPtr any, sav_any;
XAnyClassPtr Any;
+ char *end = NULL;
unsigned char *nptr, *Nptr;
int i;
unsigned long rlen;
@@ -213,16 +218,20 @@ XListInputDevices(
any = (xAnyClassPtr) ((char *)list + (*ndevices * sizeof(xDeviceInfo)));
sav_any = any;
+ end = (char *)list + rlen;
for (i = 0; i < *ndevices; i++, list++) {
- size += SizeClassInfo(&any, (int)list->num_classes);
+ s = SizeClassInfo(&any, end - (char *)any, (int)list->num_classes);
+ if (!s)
+ goto out;
+ size += s;
}
- Nptr = ((unsigned char *)list) + rlen + 1;
+ Nptr = ((unsigned char *)list) + rlen;
for (i = 0, nptr = (unsigned char *)any; i < *ndevices; i++) {
+ if (nptr >= Nptr)
+ goto out;
size += *nptr + 1;
nptr += (*nptr + 1);
- if (nptr > Nptr)
- goto out;
}
clist = (XDeviceInfoPtr) Xmalloc(size);
diff --git a/src/XOpenDev.c b/src/XOpenDev.c
index 029dec2..4b3c460 100644
--- a/src/XOpenDev.c
+++ b/src/XOpenDev.c
@@ -53,6 +53,7 @@ SOFTWARE.
#include <config.h>
#endif
+#include <limits.h>
#include <X11/extensions/XI.h>
#include <X11/extensions/XIproto.h>
#include <X11/Xlibint.h>
@@ -86,9 +87,15 @@ XOpenDevice(
return (XDevice *) NULL;
}
- rlen = rep.length << 2;
- dev = (XDevice *) Xmalloc(sizeof(XDevice) + rep.num_classes *
- sizeof(XInputClassInfo));
+ if (rep.length < INT_MAX >> 2 &&
+ (rep.length << 2) >= rep.num_classes * sizeof(xInputClassInfo)) {
+ rlen = rep.length << 2;
+ dev = (XDevice *) Xmalloc(sizeof(XDevice) + rep.num_classes *
+ sizeof(XInputClassInfo));
+ } else {
+ rlen = 0;
+ dev = NULL;
+ }
if (dev) {
int dlen; /* data length */
diff --git a/src/XQueryDv.c b/src/XQueryDv.c
index de1c0e5..7ee2272 100644
--- a/src/XQueryDv.c
+++ b/src/XQueryDv.c
@@ -73,7 +73,7 @@ XQueryDeviceState(
xQueryDeviceStateReply rep;
XDeviceState *state = NULL;
XInputClass *any, *Any;
- char *data = NULL;
+ char *data = NULL, *end = NULL;
XExtDisplayInfo *info = XInput_find_display(dpy);
LockDisplay(dpy);
@@ -92,6 +92,7 @@ XQueryDeviceState(
if (rep.length < (INT_MAX >> 2)) {
rlen = (unsigned long) rep.length << 2;
data = Xmalloc(rlen);
+ end = data + rlen;
}
if (!data) {
_XEatDataWords(dpy, rep.length);
@@ -100,7 +101,8 @@ XQueryDeviceState(
_XRead(dpy, data, rlen);
for (i = 0, any = (XInputClass *) data; i < (int)rep.num_classes; i++) {
- if (any->length > rlen)
+ if ((char *)any + sizeof(XInputClass) > end ||
+ any->length == 0 || any->length > rlen)
goto out;
rlen -= any->length;
@@ -114,6 +116,8 @@ XQueryDeviceState(
case ValuatorClass:
{
xValuatorState *v = (xValuatorState *) any;
+ if ((char *)any + sizeof(xValuatorState) > end)
+ goto out;
size += (sizeof(XValuatorState) +
(v->num_valuators * sizeof(int)));
}
--
2.7.4