Subject: Re: xfrm: Fix initialize repl field of struct xfrm_state

From: Wei Yongjun <[email-masked]>
Date: Mon, 21 Mar 2011 17:18:18 +0800

>> On Sun, Mar 20, 2011 at 11:46:06PM -0700, David Miller wrote:
>>> Ok, thanks for the explanation.
>>>
>>> I think there is a simple way out of this:
>>>
>>> 1) Rename current xfrm_init_state to __xfrm_init_state, add
>>>    "bool init_replay" argument.  Add the xfrm_init_replay()
>>>    call, as in your patch, but conditionalized on this boolean.
>>>
>>> 2) Implement xfrm_init_state as inline, which calls
>>>    __xfrm_init_state(..., true)
>>>
>>> 3) Replace xfrm_init_state() call in xfrm_user.c with
>>>    __xfrm_init_state(..., false)
>>>
>>> This seems to avoid all the problems.  We don't need to touch every
>>> caller, and we avoid initializing the replay state twice in xfrm_user
>>>
>> Btw, looking a bit closer to this. I think it would look a bit cleaner
>> if we would add the xfrm_init_replay() call to xfrm_init_state() and
>> to move the xfrm_init_state() call in xfrm_state_construct() behind
>> the assign of the replay settings.
> The xfrm_init_replay() should be call after the call to
>   xfrm_update_ae_params(x, attrs);
> since xfrm_update_ae_params() may update the replay_esn.
>
> So we need move the xfrm_init_state()  call just before return x.

Oh, sorry, the memcpy looks like dup code since we used
kmemdup. It is the same attr XFRMA_REPLAY_ESN_VAL.

> The other issue:
> static void xfrm_update_ae_params()
> {
>         ...
>         memcpy(x->replay_esn, replay_esn,
>                        xfrm_replay_state_esn_len(replay_esn));
>        ...
> }
>
> the memcpy() may cause memory overlap if we build a special
> nl_data, we should free it and then do kmemdup()?
>
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