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From: Andi Kleen <ak@linux.intel.com>
To: js1304@gmail.com
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Alexander Potapenko <glider@google.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	kasan-dev@googlegroups.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, Namhyung Kim <namhyung@kernel.org>,
	Wengang Wang <wen.gang.wang@oracle.com>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: Re: [PATCH 02/18] vchecker: introduce the valid access checker
Date: Tue, 28 Nov 2017 11:41:08 -0800	[thread overview]
Message-ID: <87k1yajinf.fsf@linux.intel.com> (raw)
In-Reply-To: <1511855333-3570-3-git-send-email-iamjoonsoo.kim@lge.com> (js's message of "Tue, 28 Nov 2017 16:48:37 +0900")

js1304@gmail.com writes:

> From: Joonsoo Kim <iamjoonsoo.kim@lge.com>

Looks useful. Essentially unlimited hardware break points, combined
with slab.

Didn't do a full review, but noticed some things below.
> +
> +	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
> +	if (!buf)
> +		return -ENOMEM;
> +
> +	if (copy_from_user(buf, ubuf, cnt)) {
> +		kfree(buf);
> +		return -EFAULT;
> +	}
> +
> +	if (isspace(buf[0]))
> +		remove = true;

and that may be uninitialized.

and the space changes the operation? That's a strange syntax.


> +	buf[cnt - 1] = '\0';

That's an underflow of one byte if cnt is 0.


-Andi

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WARNING: multiple messages have this Message-ID (diff)
From: Andi Kleen <ak@linux.intel.com>
To: js1304@gmail.com
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Alexander Potapenko <glider@google.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	kasan-dev@googlegroups.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, Namhyung Kim <namhyung@kernel.org>,
	Wengang Wang <wen.gang.wang@oracle.com>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: Re: [PATCH 02/18] vchecker: introduce the valid access checker
Date: Tue, 28 Nov 2017 11:41:08 -0800	[thread overview]
Message-ID: <87k1yajinf.fsf@linux.intel.com> (raw)
In-Reply-To: <1511855333-3570-3-git-send-email-iamjoonsoo.kim@lge.com> (js's message of "Tue, 28 Nov 2017 16:48:37 +0900")

js1304@gmail.com writes:

> From: Joonsoo Kim <iamjoonsoo.kim@lge.com>

Looks useful. Essentially unlimited hardware break points, combined
with slab.

Didn't do a full review, but noticed some things below.
> +
> +	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
> +	if (!buf)
> +		return -ENOMEM;
> +
> +	if (copy_from_user(buf, ubuf, cnt)) {
> +		kfree(buf);
> +		return -EFAULT;
> +	}
> +
> +	if (isspace(buf[0]))
> +		remove = true;

and that may be uninitialized.

and the space changes the operation? That's a strange syntax.


> +	buf[cnt - 1] = '\0';

That's an underflow of one byte if cnt is 0.


-Andi

  reply	other threads:[~2017-11-28 19:41 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-28  7:48 [PATCH 00/18] introduce a new tool, valid access checker js1304
2017-11-28  7:48 ` js1304
2017-11-28  7:48 ` [PATCH 01/18] mm/kasan: make some kasan functions global js1304
2017-11-28  7:48   ` js1304
2017-11-28  7:48 ` [PATCH 02/18] vchecker: introduce the valid access checker js1304
2017-11-28  7:48   ` js1304
2017-11-28 19:41   ` Andi Kleen [this message]
2017-11-28 19:41     ` Andi Kleen
2017-11-29  5:36     ` Joonsoo Kim
2017-11-29  5:36       ` Joonsoo Kim
2017-12-01  5:08   ` kbuild test robot
2017-12-01  8:01     ` Joonsoo Kim
2017-12-01  8:01       ` Joonsoo Kim
2017-11-28  7:48 ` [PATCH 03/18] vchecker: mark/unmark the shadow of the allocated objects js1304
2017-11-28  7:48   ` js1304
2017-11-28  7:48 ` [PATCH 04/18] vchecker: prepare per object memory for vchecker js1304
2017-11-28  7:48   ` js1304
2017-11-28  7:48 ` [PATCH 05/18] vchecker: store/report callstack of value writer js1304
2017-11-28  7:48   ` js1304
2017-11-28  7:48 ` [PATCH 06/18] lib/stackdepot: Add is_new arg to depot_save_stack js1304
2017-11-28  7:48   ` js1304
2017-11-28  7:48 ` [PATCH 07/18] lib/stackdepot: extend stackdepot API to support per-user stackdepot js1304
2017-11-28  7:48   ` js1304
2017-11-28  7:48 ` [PATCH 08/18] vchecker: Add 'callstack' checker js1304
2017-11-28  7:48   ` js1304
2017-11-28  7:48 ` [PATCH 09/18] vchecker: Support toggle on/off of callstack check js1304
2017-11-28  7:48   ` js1304
2017-11-28  7:48 ` [PATCH 10/18] vchecker: Use __GFP_ATOMIC to save stacktrace js1304
2017-11-28  7:48   ` js1304
2017-11-28  7:48 ` [PATCH 11/18] vchecker: consistently exclude vchecker's stacktrace js1304
2017-11-28  7:48   ` js1304
2017-11-28  7:48 ` [PATCH 12/18] vchecker: fix 'remove' handling on callstack checker js1304
2017-11-28  7:48   ` js1304
2017-11-28  7:48 ` [PATCH 13/18] mm/vchecker: support inline KASAN build js1304
2017-11-28  7:48   ` js1304
2017-11-28  7:48 ` [PATCH 14/18] mm/vchecker: make callstack depth configurable js1304
2017-11-28  7:48   ` js1304
2017-11-28  7:48 ` [PATCH 15/18] mm/vchecker: pass allocation caller address to vchecker hook js1304
2017-11-28  7:48   ` js1304
2017-12-01  2:39   ` kbuild test robot
2017-12-01  3:01   ` kbuild test robot
2017-11-28  7:48 ` [PATCH 16/18] mm/vchecker: support allocation caller filter js1304
2017-11-28  7:48   ` js1304
2017-11-28  7:48 ` [PATCH 17/18] lib/vchecker_test: introduce a sample for vchecker test js1304
2017-11-28  7:48   ` js1304
2017-11-28  7:48 ` [PATCH 18/18] doc: add vchecker document js1304
2017-11-28  7:48   ` js1304
2017-11-29  9:27 ` [PATCH 00/18] introduce a new tool, valid access checker Dmitry Vyukov
2017-11-29  9:27   ` Dmitry Vyukov
2017-12-01  7:46   ` Joonsoo Kim
2017-12-01  7:46     ` Joonsoo Kim
2017-12-22  1:51 ` Joonsoo Kim
2017-12-22  1:51   ` Joonsoo Kim
2018-01-18 22:39   ` Andrew Morton
2018-01-18 22:39     ` Andrew Morton

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