Re: xfrm: Fix initialize repl field of struct xfrm_state

[David Miller <davem@davemloft.net>]

From: Wei Yongjun <yjwei@cn.fujitsu.com>
Date: Mon, 21 Mar 2011 14:36:45 +0800

> Sorry for not said clearly, at the first time I want to do like this. 
> But when I grep 'xfrm_init_state', it be used in many place, not
> any pf_key, but also XFRM MIGRATE, ipcomp, ipcomp6. So I did this ugly
> patch by add this to xfrm_init_state() to avoid dup code.
> 
> Not sure whether the other case like ipcomp/ipcomp6 etc can cause panic, if
> it panic, maybe we can fix by introduce new xfrm_init_replay() function
> like to assign the default reply function.
>   int xfrm_init_replay(struct xfrm_state *x)
>   {
>   	x->repl = &xfrm_replay_legacy;
>   	return 0;
>   }
> and change the orig xfrm_init_replay to xfrm_update_replay()? 
> Or dup those code to all used place?
> 
> If I was wrong, I will fix this by adding the necessary call to af_key.c.

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

Ok?