[U-Boot] [PATCH 2/2] mtd: fix Coverity integer handling issue

Miquel Raynal miquel.raynal at bootlin.com
Sun Nov 18 20:13:47 UTC 2018


Hello,

Miquel Raynal <miquel.raynal at bootlin.com> wrote on Sun, 18 Nov 2018
21:11:47 +0100:

> A Coverity robot reported an integer handling issue
> (OVERFLOW_BEFORE_WIDEN) in the potentially overflowing expression:
> 
>     (mtd_div_by_ws(mtd->size, mtd) - mtd_div_by_ws(offs, mtd)) *
>     mtd_oobavail(mtd, ops)
> 
> While such overflow will certainly never happen due to the numbers
> handled, it is cleaner to fix this operation anyway.
> 
> The problem is that all the maths include 32-bit quantities, while the
> result is stored in an explicit 64-bit value.
> 
> As maxooblen will just be compared with a size_t, let's change the
> type of the variable to a size_t. This will not fix anything but will
> clarify a bit the situation. Then, do an explicit cast to fix Coverity
> warning.
> 
> Addresses-Coverity-ID: 184180 ("Integer handling issues")
> Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
> ---

I forgot to add the link to the corresponding Travis-CI job:
https://travis-ci.org/miquelraynal/u-boot/builds/456679982

Thanks,
Miquèl


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