From: David Miller <davem@davemloft.net>
To: sasha.levin@oracle.com
Cc: a.ryabinin@samsung.com, pablo@netfilter.org, mschmidt@redhat.com,
akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
netdev@vger.kernel.org
Subject: Re: [PATCH] netlink: don't copy over empty attribute data
Date: Sun, 26 Oct 2014 22:03:50 -0400 (EDT) [thread overview]
Message-ID: <20141026.220350.2098346782596904995.davem@davemloft.net> (raw)
In-Reply-To: <544D849A.4040304@oracle.com>
From: Sasha Levin <sasha.levin@oracle.com>
Date: Sun, 26 Oct 2014 19:32:42 -0400
> How so? GCC states clearly that you should *never* pass a NULL
> pointer there:
>
> "The pointers passed to memmove (and similar functions in <string.h>) must
> be non-null even when nbytes==0" (https://gcc.gnu.org/gcc-4.9/porting_to.html).
>
> Even if it doesn't dereference it, it can break somehow in a subtle way. Leaving
> the kernel code assuming that gcc (or any other compiler) would always behave
> the same in a situation that shouldn't occur.
Show me a legal way in which one could legally dereference the pointer
when length is zero, and I'll entertain this patch.
next prev parent reply other threads:[~2014-10-27 2:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-21 20:51 [PATCH] netlink: don't copy over empty attribute data Sasha Levin
2014-10-22 1:39 ` David Miller
2014-10-22 2:19 ` Sasha Levin
2014-10-22 6:15 ` David Miller
2014-10-26 23:32 ` Sasha Levin
2014-10-27 2:03 ` David Miller [this message]
2014-10-27 14:42 ` Sasha Levin
2014-10-27 16:46 ` Andrey Ryabinin
2014-10-22 8:55 ` David Laight
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