These values come from the user in kyrofb_ioctl(). There are a couple
potential divide by zero problems and I have added tests for them.
There were a couple tests to prevent divide by zero bugs already in the
code that I moved next to the assignments.
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
diff --git a/drivers/video/kyro/STG4000OverlayDevice.c b/drivers/video/kyro/STG4000OverlayDevice.c
index 84b6ea8..d03a1e4 100644
--- a/drivers/video/kyro/STG4000OverlayDevice.c
+++ b/drivers/video/kyro/STG4000OverlayDevice.c
@@ -365,15 +365,18 @@ int SetOverlayViewPort(volatile STG4000REG __iomem *pSTGReg,
ulSrcBottom = srcDest.ulSrcY2;
ulSrc = ulSrcBottom - ulSrcTop;
- ulDest = srcDest.lDstY2 - srcDest.lDstY1; /* on-screen overlay */
-
if (ulSrc <= 1)
return -EINVAL;
+ ulDest = srcDest.lDstY2 - srcDest.lDstY1; /* on-screen overlay */
+ if (ulDest == -1)
+ return -EINVAL;
/* First work out the position we are to display as offset from the
* source of the buffer
*/
ulFxScale = (ulDest << 11) / ulSrc; /* fixed point scale factor */
+ if (ulFxScale == 0)
+ return -EINVAL;
ulFxOffset = (srcDest.lDstY2 - srcDest.ulDstY2) << 11;
ulSrcBottom = ulSrcBottom - (ulFxOffset / ulFxScale);
@@ -430,6 +433,8 @@ int SetOverlayViewPort(volatile STG4000REG __iomem *pSTGReg,
*/
ulSrc = srcDest.ulSrcX2 - srcDest.ulSrcX1;
ulDest = srcDest.lDstX2 - srcDest.lDstX1;
+ if (ulDest == 0)
+ return -EINVAL;
if (srcDest.ulDstX1 > 2) {
ulLeft = srcDest.ulDstX1 + 2;
@@ -438,14 +443,14 @@ int SetOverlayViewPort(volatile STG4000REG __iomem *pSTGReg,
ulLeft = srcDest.ulDstX1;
ulRight = srcDest.ulDstX2 + 1;
}
+ if (ulRight - ulLeft + 2 == 0)
+ return -EINVAL;
+
/* first work out the position we are to display as offset from the source of the buffer */
bResult = 1;
do {
- if (ulDest == 0)
- return -EINVAL;
-
/* source pixels per dest pixel <<11 */
ulFxScale = ((ulSrc - 1) << 11) / (ulDest);
--
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