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From: David Howells on 22 Mar 2010 08:10
Dan Carpenter <error27(a)gmail.com> wrote:

> It seems clear from the surrounding code that xpermits is allowed to be
> NULL here.

Interesting. The memcpy() won't oops due to this because if it is given a
NULL pointer, it will also be given a zero count. I wonder if this means the
if-statement your patch adds is actually unnecessary...

David
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From: Dan Carpenter on 22 Mar 2010 09:00
On Mon, Mar 22, 2010 at 12:05:20PM +0000, David Howells wrote:
> Dan Carpenter <error27(a)gmail.com> wrote:
>
> > It seems clear from the surrounding code that xpermits is allowed to be
> > NULL here.
>
> Interesting. The memcpy() won't oops due to this because if it is given a
> NULL pointer, it will also be given a zero count. I wonder if this means the
> if-statement your patch adds is actually unnecessary...
>

I was concerned about the dereference here:

+ if (xpermits)
+ memcpy(permits->permits, xpermits->permits,
^^^^^^^^^^^^^^^^^
+ count * sizeof(struct afs_permit));

This code has been there for three years, so yeah, you would think if it
were a problem someone would have complained. My theory was "xpermits"
was almost always non-null.

regards,
dan carpenter

> David
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From: David Howells on 22 Mar 2010 09:10
Dan Carpenter <error27(a)gmail.com> wrote:

> I was concerned about the dereference here:
>
> + if (xpermits)
> + memcpy(permits->permits, xpermits->permits,
> ^^^^^^^^^^^^^^^^^
> + count * sizeof(struct afs_permit));

That's a good point - in which case your patch should definitely go in.

David
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