Fix CVE-2016-7945: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-7945 Patch copied from upstream source repository: https://cgit.freedesktop.org/xorg/lib/libXi/commit/?id=19a9cd607de73947fcfb104682f203ffe4e1f4e5 From 19a9cd607de73947fcfb104682f203ffe4e1f4e5 Mon Sep 17 00:00:00 2001 From: Tobias Stoeckmann Date: Sun, 25 Sep 2016 22:31:34 +0200 Subject: [PATCH] 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 Reviewed-by: Matthieu Herrb --- 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)))) && + rep.nEvents * (rep.axes + 1) <= rep.length) { 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 #endif +#include #include #include #include @@ -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 #endif +#include #include #include #include @@ -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 --- a/src/XIQueryDevice.c +++ b/src/XIQueryDevice.c @@ -26,6 +26,7 @@ #include #endif +#include #include #include #include @@ -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 #endif +#include #include #include #include @@ -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))); } -- 2.10.1