PATCH 2.4.19: drivers/video/sbusfb.c

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integer overflow in index + count, leading to unbounded copies.

patch has not been tested or verified.

--
Silvio
diff -u  drivers/video/sbusfb.c.2.4.19 drivers/video/sbusfb.c 
--- drivers/video/sbusfb.c.2.4.19       Tue Aug  6 21:17:39 2002
+++ drivers/video/sbusfb.c      Tue Aug  6 21:21:50 2002
@@ -599,7 +599,8 @@
                break;
        case FBIOGETCMAP_SPARC: {
                char *rp, *gp, *bp;
-               int end, count, index;
+               int count, index;
+               unsigned int end;
                struct fbcmap *cmap;
 
                if (!fb->loadcmap)
@@ -612,7 +613,10 @@
                        return -EFAULT;
                if ((index < 0) || (index > 255))
                        return -EINVAL;
-               if (index + count > 256)
+               if ((count < 0) || (count > 256))
+                       return -EINVAL;
+               end = index + count;
+               if (end > 256)
                        count = 256 - index;
                if (__get_user(rp, &cmap->red) ||
                    __get_user(gp, &cmap->green) ||
@@ -624,7 +628,6 @@
                        return -EFAULT;
                if (verify_area (VERIFY_WRITE, bp, count))
                        return -EFAULT;
-               end = index + count;
                for (i = index; i < end; i++){
                        if (__put_user(fb->color_map CM(i,0), rp) ||
                            __put_user(fb->color_map CM(i,1), gp) ||
@@ -637,7 +640,8 @@
        }
        case FBIOPUTCMAP_SPARC: {       /* load color map entries */
                char *rp, *gp, *bp;
-               int end, count, index;
+               int count, index;
+               unsigned int end;
                struct fbcmap *cmap;
                
                if (!fb->loadcmap || !fb->color_map)
@@ -650,7 +654,10 @@
                        return -EFAULT;
                if ((index < 0) || (index > 255))
                        return -EINVAL;
-               if (index + count > 256)
+               if ((count < 0) || (count > 256))
+                       return -EINVAL;
+               end = index + count;
+               if (end > 256)
                        count = 256 - index;
                if (__get_user(rp, &cmap->red) ||
                    __get_user(gp, &cmap->green) ||
@@ -663,7 +670,6 @@
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• Next message: Martin J. Bligh: "Re: fix CONFIG_HIGHPTE"
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