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Message-Id: <20100115.173044.102257749.davem@davemloft.net>
Date: Fri, 15 Jan 2010 17:30:44 -0800 (PST)
From: David Miller <davem@...emloft.net>
To: hartleys@...ionengravers.com
Cc: linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
kuznet@....inr.ac.ru, pekkas@...core.fi, jmorris@...ei.org,
yoshfuji@...ux-ipv6.org, kaber@...sh.net
Subject: Re: [PATCH] ipv4/ip_sockglue.c: copy msg_control optval from user
to kernel space
From: H Hartley Sweeten <hartleys@...ionengravers.com>
Date: Fri, 15 Jan 2010 10:24:59 -0700
> ipv4/ip_sockglue.c: copy msg_control optval from user to kernel space
>
> In do_ip_getsockopt the char __user *optval is used directly in
> IP_PKTOPTIONS for the msg.msg_control and not copied from
> user to kernel address space. This produces a sparse warning:
>
> warning: incorrect type in assignment (different address spaces)
> expected void *msg_control
> got char [noderef] <asn:1>*optval
>
> Fix this by using copy _from_user to set msg.msg_control.
>
> Signed-off-by: H Hartley Sweeten <hsweeten@...ionengravers.com>
This isn't right.
We want the 'optval' pointer itself, not the data it points to, stored
in msg.msg_control
And 'msg_control' is, in this case a user pointer.
It just isn't annotated (along with the rest of struct msghdr) with
"__user" because we mix the usage of this object with kernel and user
pointers.
How did you test your change?
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