[patch 2/2] video/kyro: some potential divide by zero bugs
From: Dan Carpenter <hidden>
Date: 2013-01-25 06:42:59
Also in:
kernel-janitors
Subsystem:
framebuffer layer, the rest · Maintainers:
Helge Deller, Linus Torvalds
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 <redacted>
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);