Fix for CVE-2007-6429 - MIT-SHM and EVI extensions integer overflows.

3 files changed, 76 insertions, 14 deletions

diff --git a/Xext/EVI.c b/Xext/EVI.c
index 4bd050ca7..a637bae5d 100644
--- a/Xext/EVI.c
+++ b/Xext/EVI.c
@@ -34,6 +34,7 @@ THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include <X11/extensions/XEVIstr.h>
 #include "EVIstruct.h"
 #include "modinit.h"
+#include "scrnintstr.h"
 
 static EviPrivPtr eviPriv;
 
@@ -84,10 +85,22 @@ ProcEVIGetVisualInfo(ClientPtr client)
 {
     REQUEST(xEVIGetVisualInfoReq);
     xEVIGetVisualInfoReply rep;
-    int n, n_conflict, n_info, sz_info, sz_conflict;
+    int i, n, n_conflict, n_info, sz_info, sz_conflict;
     VisualID32 *conflict;
+    unsigned int total_visuals = 0;
     xExtendedVisualInfo *eviInfo;
     int status;
+
+    /*
+     * do this first, otherwise REQUEST_FIXED_SIZE can overflow.  we assume
+     * here that you don't have more than 2^32 visuals over all your screens;
+     * this seems like a safe assumption.
+     */
+    for (i = 0; i < screenInfo.numScreens; i++)
+	total_visuals += screenInfo.screens[i]->numVisuals;
+    if (stuff->n_visual > total_visuals)
+	return BadValue;
+
     REQUEST_FIXED_SIZE(xEVIGetVisualInfoReq, stuff->n_visual * sz_VisualID32);
     status = eviPriv->getVisualInfo((VisualID32 *)&stuff[1], (int)stuff->n_visual,
 		&eviInfo, &n_info, &conflict, &n_conflict);
diff --git a/Xext/sampleEVI.c b/Xext/sampleEVI.c
index 7508aa773..b871bfd74 100644
--- a/Xext/sampleEVI.c
+++ b/Xext/sampleEVI.c
@@ -34,6 +34,13 @@ THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include <X11/extensions/XEVIstr.h>
 #include "EVIstruct.h"
 #include "scrnintstr.h"
+
+#if HAVE_STDINT_H
+#include <stdint.h>
+#elif !defined(UINT32_MAX)
+#define UINT32_MAX 0xffffffffU
+#endif
+
 static int sampleGetVisualInfo(
     VisualID32 *visual,
     int n_visual,
@@ -42,24 +49,36 @@ static int sampleGetVisualInfo(
     VisualID32 **conflict_rn,
     int *n_conflict_rn)
 {
-    int max_sz_evi = n_visual * sz_xExtendedVisualInfo * screenInfo.numScreens;
+    unsigned int max_sz_evi;
     VisualID32 *temp_conflict;
     xExtendedVisualInfo *evi;
-    int max_visuals = 0, max_sz_conflict, sz_conflict = 0;
+    unsigned int max_visuals = 0, max_sz_conflict, sz_conflict = 0;
     register int visualI, scrI, sz_evi = 0, conflictI, n_conflict;
-    *evi_rn = evi = (xExtendedVisualInfo *)xalloc(max_sz_evi);
-    if (!*evi_rn)
-         return BadAlloc;
+
+    if (n_visual > UINT32_MAX/(sz_xExtendedVisualInfo * screenInfo.numScreens))
+	return BadAlloc;
+    max_sz_evi = n_visual * sz_xExtendedVisualInfo * screenInfo.numScreens;
+    
     for (scrI = 0; scrI < screenInfo.numScreens; scrI++) {
         if (screenInfo.screens[scrI]->numVisuals > max_visuals)
             max_visuals = screenInfo.screens[scrI]->numVisuals;
     }
+
+    if (n_visual > UINT32_MAX/(sz_VisualID32 * screenInfo.numScreens 
+			       * max_visuals)) 
+	return BadAlloc;
     max_sz_conflict = n_visual * sz_VisualID32 * screenInfo.numScreens * max_visuals;
+
+    *evi_rn = evi = (xExtendedVisualInfo *)xalloc(max_sz_evi);
+    if (!*evi_rn)
+         return BadAlloc;
+
     temp_conflict = (VisualID32 *)xalloc(max_sz_conflict);
     if (!temp_conflict) {
         xfree(*evi_rn);
         return BadAlloc;
     }
+
     for (scrI = 0; scrI < screenInfo.numScreens; scrI++) {
         for (visualI = 0; visualI < n_visual; visualI++) {
 	    evi[sz_evi].core_visual_id = visual[visualI];
diff --git a/Xext/shm.c b/Xext/shm.c
index e3d7a23ff..c545e4919 100644
--- a/Xext/shm.c
+++ b/Xext/shm.c
@@ -757,6 +757,8 @@ ProcPanoramiXShmCreatePixmap(
     int i, j, result, rc;
     ShmDescPtr shmdesc;
     REQUEST(xShmCreatePixmapReq);
+    unsigned int width, height, depth;
+    unsigned long size;
     PanoramiXRes *newPix;
 
     REQUEST_SIZE_MATCH(xShmCreatePixmapReq);
@@ -770,11 +772,26 @@ ProcPanoramiXShmCreatePixmap(
 	return rc;
 
     VERIFY_SHMPTR(stuff->shmseg, stuff->offset, TRUE, shmdesc, client);
-    if (!stuff->width || !stuff->height)
+
+    width = stuff->width;
+    height = stuff->height;
+    depth = stuff->depth;
+    if (!width || !height || !depth)
     {
 	client->errorValue = 0;
         return BadValue;
     }
+    if (width > 32767 || height > 32767)
+        return BadAlloc;
+    size = PixmapBytePad(width, depth) * height;
+    if (sizeof(size) == 4) {
+        if (size < width * height)
+            return BadAlloc;
+        /* thankfully, offset is unsigned */
+        if (stuff->offset + size < size)
+            return BadAlloc;
+    }
+
     if (stuff->depth != 1)
     {
         pDepth = pDraw->pScreen->allowedDepths;
@@ -785,9 +802,7 @@ ProcPanoramiXShmCreatePixmap(
         return BadValue;
     }
 CreatePmap:
-    VERIFY_SHMSIZE(shmdesc, stuff->offset,
-		   PixmapBytePad(stuff->width, stuff->depth) * stuff->height,
-		   client);
+    VERIFY_SHMSIZE(shmdesc, stuff->offset, size, client);
 
     if(!(newPix = (PanoramiXRes *) xalloc(sizeof(PanoramiXRes))))
 	return BadAlloc;
@@ -1086,6 +1101,8 @@ ProcShmCreatePixmap(client)
     register int i, rc;
     ShmDescPtr shmdesc;
     REQUEST(xShmCreatePixmapReq);
+    unsigned int width, height, depth;
+    unsigned long size;
 
     REQUEST_SIZE_MATCH(xShmCreatePixmapReq);
     client->errorValue = stuff->pid;
@@ -1098,11 +1115,26 @@ ProcShmCreatePixmap(client)
 	return rc;
 
     VERIFY_SHMPTR(stuff->shmseg, stuff->offset, TRUE, shmdesc, client);
-    if (!stuff->width || !stuff->height)
+    
+    width = stuff->width;
+    height = stuff->height;
+    depth = stuff->depth;
+    if (!width || !height || !depth)
     {
 	client->errorValue = 0;
         return BadValue;
     }
+    if (width > 32767 || height > 32767)
+	return BadAlloc;
+    size = PixmapBytePad(width, depth) * height;
+    if (sizeof(size) == 4) {
+	if (size < width * height)
+	    return BadAlloc;
+	/* thankfully, offset is unsigned */
+	if (stuff->offset + size < size)
+	    return BadAlloc;
+    }
+
     if (stuff->depth != 1)
     {
         pDepth = pDraw->pScreen->allowedDepths;
@@ -1113,9 +1145,7 @@ ProcShmCreatePixmap(client)
         return BadValue;
     }
 CreatePmap:
-    VERIFY_SHMSIZE(shmdesc, stuff->offset,
-		   PixmapBytePad(stuff->width, stuff->depth) * stuff->height,
-		   client);
+    VERIFY_SHMSIZE(shmdesc, stuff->offset, size, client);
     pMap = (*shmFuncs[pDraw->pScreen->myNum]->CreatePixmap)(
 			    pDraw->pScreen, stuff->width,
 			    stuff->height, stuff->depth,