linux-kernel - Re: [PATCH 1/3] tools/hv: Fix for long file names from readdir

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Date:	Tue, 27 Nov 2012 15:28:25 -0500 (EST)
From:	Tomas Hozza <thozza@...hat.com>
To:	Ben Hutchings <ben@...adent.org.uk>
Cc:	gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
	devel@...uxdriverproject.org, olaf@...fle.de, apw@...onical.com,
	jasowang@...hat.com, kys@...rosoft.com
Subject: Re: [PATCH 1/3] tools/hv: Fix for long file names from readdir



----- Original Message -----
> On Tue, 2012-11-27 at 08:56 +0100, Tomas Hozza wrote:
> > kvp_get_if_name and kvp_mac_to_if_name copy strings into statically
> > sized buffers which could be too small to store really long names.
> >
> > Buffer sizes have been changed to PATH_MAX, include "limits.h"
> > where
> > PATH_MAX is defined was added and length checks ware added via
> > snprintf.
> [...]
> 
> PATH_MAX has nothing to do with any actual kernel limit; it's no more
> meaningful than the current value of 256.  Network interface names
> are
> limited to 15 characters, thus the current array is more than long
> enough.  So I think this is entirely unnecessary.

This is just for sanity. The value PATH_MAX was chosen after discussion
with K. Y. Srinivasan and Olaf Hering instead of some "magic" number like
256 or 512.

> Using snprintf() is a good idea, but you need to check the return
> value and handle the truncation case somehow.

By using PATH_MAX sized buffer there is no need for handling the truncation
case.


Tomas Hozza
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