From mboxrd@z Thu Jan  1 00:00:00 1970
To: 9fans@cse.psu.edu
Date: Fri, 16 Nov 2007 10:18:54 +0000
From: "Douglas A. Gwyn" <DAGwyn@null.net>
Message-ID: <473CA225.86119D3C@null.net>
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References: <15aabbdb3c4953608a4f19497b3bffb0@terzarima.net>,
	<815f4e4b0711091501v53a37569x5c5f576623fb9547@mail.gmail.com>
Subject: Re: [9fans] Bounds checking bug ifcall(2) functions
Topicbox-Message-UUID: fc734ec0-ead2-11e9-9d60-3106f5b1d025

Erik Dal=E9n wrote:
> On second thought I think you are correct. At the end of the function
> the pointer might be one byte past the buffer size, but then it won't
> do any reads or writes (But it could be a problem if the buffer is
> right at the end of the virtual memory space :).

The C standard requires that pointer arithmetic work properly
for one-past-the-end pointers.  On some architectures that may
mean that each data segment has to have an extra (unused) byte
allocated, but on most architectures nothing special has to be
done.