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

Miquel Raynal miquel.raynal at bootlin.com
Mon Apr 8 13:42:06 UTC 2019


Hi Tom,

Tom Rini <trini at konsulko.com> wrote on Mon, 8 Apr 2019 07:52:16 -0400:

> On Mon, Apr 08, 2019 at 11:43:59AM +0200, Miquel Raynal wrote:
> > Hello,
> > 
> > Miquel Raynal <miquel.raynal at bootlin.com> wrote on Sun, 18 Nov 2018
> > 21:13:47 +0100:
> >   
> > > 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  
> > 
> > Gentle ping on this series (patch 1 & 2). They do apply cleanly on
> > current master.
> > 
> > Tom, shall I expect you to take it or is it Jagan's mission?  
> 
> My current feeling is this goes via Jagan's tree and I wasn't expecting
> them in for this release.  Thanks!
> 

No problem, I know we are late in the merge process, these are just
Coverity fixes, they are not urgent, I just am cleaning my branches and
I discover many patches which I thought were merged but actually only
exist in my local tree, which is sad :)


Thanks,
Miquèl
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