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Date:   Wed, 30 Oct 2019 11:59:00 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Iurii Zaikin <yzaikin@google.com>
Cc:     Brendan Higgins <brendanhiggins@google.com>,
        shuah <shuah@kernel.org>, john.johansen@canonical.com,
        jmorris@namei.org, serge@hallyn.com, alan.maguire@oracle.com,
        davidgow@google.com, Luis Chamberlain <mcgrof@kernel.org>,
        Theodore Ts'o <tytso@mit.edu>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-security-module@vger.kernel.org,
        KUnit Development <kunit-dev@googlegroups.com>,
        "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@vger.kernel.org>,
        Mike Salvatore <mike.salvatore@canonical.com>
Subject: Re: [PATCH linux-kselftest/test v1] apparmor: add AppArmor KUnit
 tests for policy unpack
Message-ID: <201910301157.58D0CE4D3@keescook>
References: <20191018001816.94460-1-brendanhiggins@google.com>
 <CAAXuY3rLEt9nqOBSNaWjLMHNg6pDHdjtg7hFiYx-KCDhyfnkcg@mail.gmail.com>
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On Thu, Oct 17, 2019 at 05:33:56PM -0700, Iurii Zaikin wrote:
> On Thu, Oct 17, 2019 at 5:19 PM Brendan Higgins
> <brendanhiggins@google.com> wrote:
> 
> > +config SECURITY_APPARMOR_TEST
> > +       bool "Build KUnit tests for policy_unpack.c"
> > +       default n

New options already already default n, this can be left off.

> > +       depends on KUNIT && SECURITY_APPARMOR
> > +       help
> >
> select SECURITY_APPARMOR ?

"select" doesn't enforce dependencies, so just a "depends ..." is
correct.

> > +       KUNIT_EXPECT_EQ(test, size, TEST_BLOB_DATA_SIZE);
> > +       KUNIT_EXPECT_TRUE(test,
> > +               memcmp(blob, TEST_BLOB_DATA, TEST_BLOB_DATA_SIZE) == 0);
> I think this must be  KUNIT_ASSERT_EQ(test, size, TEST_BLOB_DATA_SIZE);,
> otherwise there could be a buffer overflow in memcmp. All tests that
> follow such pattern

Agreed.

> are suspect. Also, not sure about your stylistic preference for
> KUNIT_EXPECT_TRUE(test,
>                memcmp(blob, TEST_BLOB_DATA, TEST_BLOB_DATA_SIZE) == 0);
> vs
> KUNIT_EXPECT_EQ(test,
>                0,
>                memcmp(blob, TEST_BLOB_DATA, TEST_BLOB_DATA_SIZE));

I like == 0.

-- 
Kees Cook