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Date:   Mon, 7 Jun 2021 11:34:16 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Liangyan <liangyan.peng@linux.alibaba.com>
Cc:     linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
        Xunlei Pang <xlpang@linux.alibaba.com>,
        yinbinbin@alibabacloud.com, wetp <wetp.zy@linux.alibaba.com>,
        jnwang@linux.alibaba.com, stable@vger.kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH] tracing: Correct the length check which causes memory
 corruption
Message-ID: <20210607113416.603c72d3@oasis.local.home>
In-Reply-To: <20210607125734.1770447-1-liangyan.peng@linux.alibaba.com>
References: <20210607125734.1770447-1-liangyan.peng@linux.alibaba.com>
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On Mon,  7 Jun 2021 20:57:34 +0800
Liangyan <liangyan.peng@linux.alibaba.com> wrote:

> commit b220c049d519 ("tracing: Check length before giving out
> the filter buffer") adds length check to protect trace data
> overflow introduced in 0fc1b09ff1ff, seems that this fix can't prevent
> overflow entirely, the length check should also take the sizeof
> entry->array[0] into account, since this array[0] is filled the
> length of trace data and occupy addtional space and risk overflow.

Bah, you're right! I didn't take into account that when the event is
this big, array[] will have content.

I queued the patch and will start testing it.

Thanks!

-- Steve