From: Walter Wu <walter-zh.wu@mediatek.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Matthias Brugger <matthias.bgg@gmail.com>,
<kasan-dev@googlegroups.com>, <linux-mm@kvack.org>,
<linux-kernel@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-mediatek@lists.infradead.org>, <wsd_upstream@mediatek.com>
Subject: Re: [PATCH 2/2] kasan: add test for invalid size in memmove
Date: Mon, 14 Oct 2019 23:57:11 +0800 [thread overview]
Message-ID: <1571068631.8898.8.camel@mtksdccf07> (raw)
In-Reply-To: <20191014150710.GY32665@bombadil.infradead.org>
On Mon, 2019-10-14 at 08:07 -0700, Matthew Wilcox wrote:
> On Mon, Oct 14, 2019 at 06:36:54PM +0800, Walter Wu wrote:
> > Test size is negative numbers in memmove in order to verify
> > whether it correctly get KASAN report.
>
> You're not testing negative numbers, though. memmove() takes an unsigned
> type, so you're testing a very large number.
>
Casting negative numbers to size_t would indeed turn up as a "large"
size_t and its value will be larger than ULONG_MAX/2. We mainly want to
express this case. Maybe we can add some descriptions. Thanks for your
reminder.
WARNING: multiple messages have this Message-ID (diff)
From: Walter Wu <walter-zh.wu@mediatek.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: wsd_upstream@mediatek.com, linux-mediatek@lists.infradead.org,
linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
linux-mm@kvack.org, Alexander Potapenko <glider@google.com>,
linux-arm-kernel@lists.infradead.org,
Matthias Brugger <matthias.bgg@gmail.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [PATCH 2/2] kasan: add test for invalid size in memmove
Date: Mon, 14 Oct 2019 23:57:11 +0800 [thread overview]
Message-ID: <1571068631.8898.8.camel@mtksdccf07> (raw)
In-Reply-To: <20191014150710.GY32665@bombadil.infradead.org>
On Mon, 2019-10-14 at 08:07 -0700, Matthew Wilcox wrote:
> On Mon, Oct 14, 2019 at 06:36:54PM +0800, Walter Wu wrote:
> > Test size is negative numbers in memmove in order to verify
> > whether it correctly get KASAN report.
>
> You're not testing negative numbers, though. memmove() takes an unsigned
> type, so you're testing a very large number.
>
Casting negative numbers to size_t would indeed turn up as a "large"
size_t and its value will be larger than ULONG_MAX/2. We mainly want to
express this case. Maybe we can add some descriptions. Thanks for your
reminder.
WARNING: multiple messages have this Message-ID (diff)
From: Walter Wu <walter-zh.wu@mediatek.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: wsd_upstream@mediatek.com, linux-mediatek@lists.infradead.org,
linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
linux-mm@kvack.org, Alexander Potapenko <glider@google.com>,
linux-arm-kernel@lists.infradead.org,
Matthias Brugger <matthias.bgg@gmail.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [PATCH 2/2] kasan: add test for invalid size in memmove
Date: Mon, 14 Oct 2019 23:57:11 +0800 [thread overview]
Message-ID: <1571068631.8898.8.camel@mtksdccf07> (raw)
In-Reply-To: <20191014150710.GY32665@bombadil.infradead.org>
On Mon, 2019-10-14 at 08:07 -0700, Matthew Wilcox wrote:
> On Mon, Oct 14, 2019 at 06:36:54PM +0800, Walter Wu wrote:
> > Test size is negative numbers in memmove in order to verify
> > whether it correctly get KASAN report.
>
> You're not testing negative numbers, though. memmove() takes an unsigned
> type, so you're testing a very large number.
>
Casting negative numbers to size_t would indeed turn up as a "large"
size_t and its value will be larger than ULONG_MAX/2. We mainly want to
express this case. Maybe we can add some descriptions. Thanks for your
reminder.
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-10-14 15:57 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-14 10:36 [PATCH 2/2] kasan: add test for invalid size in memmove Walter Wu
2019-10-14 10:36 ` Walter Wu
2019-10-14 10:36 ` Walter Wu
2019-10-14 10:41 ` Dmitry Vyukov
2019-10-14 10:41 ` Dmitry Vyukov
2019-10-14 10:41 ` Dmitry Vyukov
2019-10-14 15:07 ` Matthew Wilcox
2019-10-14 15:07 ` Matthew Wilcox
2019-10-14 15:57 ` Walter Wu [this message]
2019-10-14 15:57 ` Walter Wu
2019-10-14 15:57 ` Walter Wu
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