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From: Arnd Bergmann <arnd@arndb.de>
To: Mimi Zohar <zohar@linux.ibm.com>
Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>,
	James Morris <jmorris@namei.org>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	Stefan Berger <stefanb@linux.vnet.ibm.com>,
	linux-integrity@vger.kernel.org,
	LSM List <linux-security-module@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] ima: dynamically allocate shash_desc
Date: Mon, 17 Jun 2019 22:08:02 +0200	[thread overview]
Message-ID: <CAK8P3a1Q2JG3KBYNYgWg0_XtGUufNc6zuqcUBqiGSaBRp+au-w@mail.gmail.com> (raw)
In-Reply-To: <1560794826.4072.169.camel@linux.ibm.com>

On Mon, Jun 17, 2019 at 8:08 PM Mimi Zohar <zohar@linux.ibm.com> wrote:
>
> On Mon, 2019-06-17 at 11:55 -0400, Mimi Zohar wrote:
> > On Mon, 2019-06-17 at 13:20 +0200, Arnd Bergmann wrote:
> > > On 32-bit ARM, we get a warning about excessive stack usage when
> > > building with clang.
> > >
> > > security/integrity/ima/ima_crypto.c:504:5: error: stack frame size
> > > of 1152 bytes in function 'ima_calc_field_array_hash' [-Werror,-
> > > Wframe-larger-than=]
> >
> > I'm definitely not seeing this.  Is this problem a result of non
> > upstreamed patches?  For sha1, currently the only possible hash
> > algorithm, I'm seeing 664.

You won't see it with gcc, only with clang in some randconfig builds,
I suppose only when KASAN is enabled.

> Every time a measurement is added to the measurement list, the memory
> would be allocated/freed.  The frequency of new measurements is policy
> dependent.  For performance reasons, I'd prefer if the allocation
> remains on the stack.

Is there a way to preallocate the shash_desc instead? That would
avoid the overhead.

        Arnd

  reply	other threads:[~2019-06-17 20:08 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-17 11:20 [PATCH] ima: dynamically allocate shash_desc Arnd Bergmann
2019-06-17 15:55 ` Mimi Zohar
2019-06-17 18:07   ` Mimi Zohar
2019-06-17 20:08     ` Arnd Bergmann [this message]
2019-06-18 12:44       ` Mimi Zohar
2019-06-18 18:06         ` Arnd Bergmann
2019-06-18 18:53           ` Mimi Zohar

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