linux-kernel - RE: [PATCH v2 5/9] selinux: services: update type for number of class permissions

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Message-ID: <764b3d9f340e403084fb44877d4a73b6@AcuMS.aculab.com>
Date:   Fri, 4 Aug 2023 15:21:31 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Paul Moore' <paul@...l-moore.com>,
        Christian Göttsche <cgzones@...glemail.com>,
        "selinux@...r.kernel.org" <selinux@...r.kernel.org>
CC:     Stephen Smalley <stephen.smalley.work@...il.com>,
        Eric Paris <eparis@...isplace.org>,
        Ondrej Mosnacek <omosnace@...hat.com>,
        "GONG, Ruiqi" <gongruiqi1@...wei.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v2 5/9] selinux: services: update type for number of class
  permissions

From: Paul Moore
> Sent: 04 August 2023 03:20
> 
> On Jul 28, 2023 =?UTF-8?q?Christian=20G=C3=B6ttsche?= <cgzones@...glemail.com> wrote:
> >
...
> > +		u16 i, n = mapping->num_perms;
...
> >  		for (; i < (sizeof(u32)*8); i++)

Don't dop arithmetic on types smaller than int.
You are pretty much requesting the compiler add code to mask the
result down to 16 bits after very operations.

	David

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