From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Colin Ian King <colin.king@canonical.com>,
Sathya Prakash <sathya.prakash@broadcom.com>,
Chaitra P B <chaitra.basappa@broadcom.com>,
Suganath Prabu Subramani <suganath-prabu.subramani@broadcom.com>,
MPT-FusionLinux.pdl@broadcom.com, linux-scsi@vger.kernel.org
Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mptsas: fix undefined behaviour of a shift of an int by more than 31 places
Date: Wed, 08 May 2019 14:24:28 +0000 [thread overview]
Message-ID: <1557325468.3196.2.camel@HansenPartnership.com> (raw)
In-Reply-To: <de7e3aaf-0155-5007-c228-510f0d0de428@canonical.com>
On Wed, 2019-05-08 at 14:07 +0100, Colin Ian King wrote:
> On 05/05/2019 04:34, James Bottomley wrote:
> > On Sat, 2019-05-04 at 17:40 +0100, Colin King wrote:
> > > From: Colin Ian King <colin.king@canonical.com>
> > >
> > > Currently the shift of int value 1 by more than 31 places can
> > > result in undefined behaviour. Fix this by making the 1 a ULL
> > > value before the shift operation.
> >
> > Fusion SAS is pretty ancient. I thought the largest one ever
> > produced had four phys, so how did you produce the overflow?
>
> This was an issue found by static analysis with Coverity; so I guess
> won't happen in the wild, in which case the patch could be ignored.
The point I was more making is that if we thought this could ever
happen in practice, we'd need more error handling than simply this:
we'd be setting the phy_bitmap to zero which would be every bit as bad
as some random illegal value.
James
WARNING: multiple messages have this Message-ID (diff)
From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Colin Ian King <colin.king@canonical.com>,
Sathya Prakash <sathya.prakash@broadcom.com>,
Chaitra P B <chaitra.basappa@broadcom.com>,
Suganath Prabu Subramani <suganath-prabu.subramani@broadcom.com>,
MPT-FusionLinux.pdl@broadcom.com, linux-scsi@vger.kernel.org
Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mptsas: fix undefined behaviour of a shift of an int by more than 31 places
Date: Wed, 08 May 2019 07:24:28 -0700 [thread overview]
Message-ID: <1557325468.3196.2.camel@HansenPartnership.com> (raw)
In-Reply-To: <de7e3aaf-0155-5007-c228-510f0d0de428@canonical.com>
On Wed, 2019-05-08 at 14:07 +0100, Colin Ian King wrote:
> On 05/05/2019 04:34, James Bottomley wrote:
> > On Sat, 2019-05-04 at 17:40 +0100, Colin King wrote:
> > > From: Colin Ian King <colin.king@canonical.com>
> > >
> > > Currently the shift of int value 1 by more than 31 places can
> > > result in undefined behaviour. Fix this by making the 1 a ULL
> > > value before the shift operation.
> >
> > Fusion SAS is pretty ancient. I thought the largest one ever
> > produced had four phys, so how did you produce the overflow?
>
> This was an issue found by static analysis with Coverity; so I guess
> won't happen in the wild, in which case the patch could be ignored.
The point I was more making is that if we thought this could ever
happen in practice, we'd need more error handling than simply this:
we'd be setting the phy_bitmap to zero which would be every bit as bad
as some random illegal value.
James
next prev parent reply other threads:[~2019-05-08 14:24 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-04 16:40 [PATCH] mptsas: fix undefined behaviour of a shift of an int by more than 31 places Colin King
2019-05-04 16:40 ` Colin King
2019-05-05 3:34 ` James Bottomley
2019-05-05 3:34 ` James Bottomley
2019-05-08 13:07 ` Colin Ian King
2019-05-08 13:07 ` Colin Ian King
2019-05-08 14:24 ` James Bottomley [this message]
2019-05-08 14:24 ` James Bottomley
2019-05-09 15:30 ` Hannes Reinecke
2019-05-09 15:30 ` Hannes Reinecke
2019-05-09 15:42 ` James Bottomley
2019-05-09 15:42 ` James Bottomley
2019-05-09 15:58 ` Colin Ian King
2019-05-09 15:58 ` Colin Ian King
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