From 8f82f69e9e4b76b01b9f5fe06d1ea86851d951c4 Mon Sep 17 00:00:00 2001
From: Alan Coopersmith <alan.coopersmith@oracle.com>
Date: Wed, 22 Jan 2014 22:37:15 -0800
Subject: [PATCH 04/31] dix: integer overflow in RegionSizeof() [CVE-2014-8092
3/4]
RegionSizeof contains several integer overflows if a large length
value is passed in. Once we fix it to return 0 on overflow, we
also have to fix the callers to handle this error condition
v2: Fixed limit calculation in RegionSizeof as pointed out by jcristau.
Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Julien Cristau <jcristau@debian.org>
Signed-off-by: Fedora X Ninjas <x@fedoraproject.org>
---
dix/region.c | 20 +++++++++++++-------
include/regionstr.h | 10 +++++++---
2 files changed, 20 insertions(+), 10 deletions(-)
diff --git a/dix/region.c b/dix/region.c
index 737d2a8..76c4e29 100644
--- a/dix/region.c
+++ b/dix/region.c
@@ -169,7 +169,6 @@ Equipment Corporation.
((r1)->y1 <= (r2)->y1) && \
((r1)->y2 >= (r2)->y2) )
-#define xallocData(n) malloc(RegionSizeof(n))
#define xfreeData(reg) if ((reg)->data && (reg)->data->size) free((reg)->data)
#define RECTALLOC_BAIL(pReg,n,bail) \
@@ -205,8 +204,9 @@ if (!(pReg)->data || (((pReg)->data->numRects + (n)) > (pReg)->data->size)) \
#define DOWNSIZE(reg,numRects) \
if (((numRects) < ((reg)->data->size >> 1)) && ((reg)->data->size > 50)) \
{ \
- RegDataPtr NewData; \
- NewData = (RegDataPtr)realloc((reg)->data, RegionSizeof(numRects)); \
+ size_t NewSize = RegionSizeof(numRects); \
+ RegDataPtr NewData = \
+ (NewSize > 0) ? realloc((reg)->data, NewSize) : NULL ; \
if (NewData) \
{ \
NewData->size = (numRects); \
@@ -330,17 +330,20 @@ Bool
RegionRectAlloc(RegionPtr pRgn, int n)
{
RegDataPtr data;
+ size_t rgnSize;
if (!pRgn->data) {
n++;
- pRgn->data = xallocData(n);
+ rgnSize = RegionSizeof(n);
+ pRgn->data = (rgnSize > 0) ? malloc(rgnSize) : NULL;
if (!pRgn->data)
return RegionBreak(pRgn);
pRgn->data->numRects = 1;
*RegionBoxptr(pRgn) = pRgn->extents;
}
else if (!pRgn->data->size) {
- pRgn->data = xallocData(n);
+ rgnSize = RegionSizeof(n);
+ pRgn->data = (rgnSize > 0) ? malloc(rgnSize) : NULL;
if (!pRgn->data)
return RegionBreak(pRgn);
pRgn->data->numRects = 0;
@@ -352,7 +355,8 @@ RegionRectAlloc(RegionPtr pRgn, int n)
n = 250;
}
n += pRgn->data->numRects;
- data = (RegDataPtr) realloc(pRgn->data, RegionSizeof(n));
+ rgnSize = RegionSizeof(n);
+ data = (rgnSize > 0) ? realloc(pRgn->data, rgnSize) : NULL;
if (!data)
return RegionBreak(pRgn);
pRgn->data = data;
@@ -1297,6 +1301,7 @@ RegionFromRects(int nrects, xRectangle *prect, int ctype)
{
RegionPtr pRgn;
+ size_t rgnSize;
RegDataPtr pData;
BoxPtr pBox;
int i;
@@ -1323,7 +1328,8 @@ RegionFromRects(int nrects, xRectangle *prect, int ctype)
}
return pRgn;
}
- pData = xallocData(nrects);
+ rgnSize = RegionSizeof(nrects);
+ pData = (rgnSize > 0) ? malloc(rgnSize) : NULL;
if (!pData) {
RegionBreak(pRgn);
return pRgn;
diff --git a/include/regionstr.h b/include/regionstr.h
index 805257b..5006207 100644
--- a/include/regionstr.h
+++ b/include/regionstr.h
@@ -127,7 +127,10 @@ RegionEnd(RegionPtr reg)
static inline size_t
RegionSizeof(int n)
{
- return (sizeof(RegDataRec) + ((n) * sizeof(BoxRec)));
+ if (n < ((INT_MAX - sizeof(RegDataRec)) / sizeof(BoxRec)))
+ return (sizeof(RegDataRec) + ((n) * sizeof(BoxRec)));
+ else
+ return 0;
}
static inline void
@@ -138,9 +141,10 @@ RegionInit(RegionPtr _pReg, BoxPtr _rect, int _size)
(_pReg)->data = (RegDataPtr) NULL;
}
else {
+ size_t rgnSize;
(_pReg)->extents = RegionEmptyBox;
- if (((_size) > 1) && ((_pReg)->data =
- (RegDataPtr) malloc(RegionSizeof(_size)))) {
+ if (((_size) > 1) && ((rgnSize = RegionSizeof(_size)) > 0) &&
+ (((_pReg)->data = malloc(rgnSize)) != NULL)) {
(_pReg)->data->size = (_size);
(_pReg)->data->numRects = 0;
}
--
1.9.3
