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From: Xi Wang <xi.wang@gmail.com>
To: David Laight <David.Laight@ACULAB.COM>
Cc: David Miller <davem@davemloft.net>, netdev@vger.kernel.org
Subject: Re: [PATCH] ipv4: avoid undefined behavior in do_ip_setsockopt()
Date: Mon, 12 Nov 2012 12:00:54 -0500	[thread overview]
Message-ID: <50A12B46.4010805@gmail.com> (raw)
In-Reply-To: <AE90C24D6B3A694183C094C60CF0A2F6026B709E@saturn3.aculab.com>

On 11/12/12 8:54 AM, David Laight wrote:
> 'All modern' is probably an overstatement, 'recent gcc' might be valid.

I agree if you consider gcc 3.4 released 8 years ago as "recent gcc",
or if you use a compiler other than gcc/clang/icc to compile the kernel.

> The 'switch' version will have an extra conditional to detect
> 'out of range' values - even though we know they can't happen.
> I'm not sure you can avoid that - even for an enum.

This out-of-range check is exactly what this patch wanted to add:
optname is a syscall parameter, and we should reject invalid optname
values before doing (1<<optname).

- xi

      reply	other threads:[~2012-11-12 17:01 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-11 21:20 [PATCH] ipv4: avoid undefined behavior in do_ip_setsockopt() Xi Wang
2012-11-11 22:02 ` David Miller
2012-11-11 22:18   ` Xi Wang
2012-11-11 22:50     ` David Miller
2012-11-12 13:54       ` David Laight
2012-11-12 17:00         ` Xi Wang [this message]

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