linux-kernel - Re: [PATCH 1/1] initramfs: strcpy destination string overflow

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Message-ID: <AANLkTinoCgO56O1kPNW3vjd9Nd1kY2SU34UH2RQa9qkE@mail.gmail.com>
Date:	Tue, 5 Oct 2010 08:55:01 -0700
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	Evgeny Kuznetsov <EXT-Eugeny.Kuznetsov@...ia.com>,
	"H. Peter Anvin" <hpa@...or.com>
Cc:	akpm@...ux-foundation.org, phillip@...gher.demon.co.uk,
	hsweeten@...ionengravers.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] initramfs: strcpy destination string overflow

On Tue, Oct 5, 2010 at 1:44 AM, Evgeny Kuznetsov
<EXT-Eugeny.Kuznetsov@...ia.com> wrote:
> From: Evgeny Kuznetsov <ext-eugeny.kuznetsov@...ia.com>
>
> Function "strcpy()" is used without check for maximum allowed
> source string length and could cause destination string overflow.
> "strcpy()" is replaced by "strlcpy()" to prevent destination
> string overflow.

I think this is wrong.

If the name is too long to fit in the hash table, we should not create
a new hash entry at all, because we'd be returning the wrong
(truncated) name when we find it next time.

So it would be much better to just do

   if (strlen(name) >= sizeof(q->name))
      return NULL;

in find_link(), because as far as I can tell, the hard-linking is
always just an optimization.

Comments? Peter?

                         Linus
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