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Date:   Thu, 24 Sep 2020 17:43:51 +1000
From:   Herbert Xu <herbert@gondor.apana.org.au>
To:     Steffen Klassert <steffen.klassert@secunet.com>
Cc:     syzbot <syzbot+577fbac3145a6eb2e7a5@syzkaller.appspotmail.com>,
        davem@davemloft.net, kuba@kernel.org, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: Re: KASAN: stack-out-of-bounds Read in xfrm_selector_match (2)
Message-ID: <20200924074351.GB9879@gondor.apana.org.au>
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 <20200924074026.GC20687@gauss3.secunet.de>
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On Thu, Sep 24, 2020 at 09:40:26AM +0200, Steffen Klassert wrote:
>
> This is yet another ipv4 mapped ipv6 address with IPsec socket policy
> combination bug, and I'm sure it is not the last one. We could fix this
> one by adding another check to match the address family of the policy
> and the SA selector, but maybe it is better to think about how this
> should work at all.
> 
> We can have only one socket policy for each direction and that
> policy accepts either ipv4 or ipv6. We treat this ipv4 mapped ipv6
> address as ipv4 and pass it down the ipv4 stack, so this dual usage
> will not work with a socket policy. Maybe we can require IPV6_V6ONLY
> for sockets with policy attached. Thoughts?

I'm looking at the history of this and it used to work at the start
because you'd always interpret the flow object with a family.  This
appears to have been lost with 8444cf712c5f71845cba9dc30d8f530ff0d5ff83. 

I'm working on a fix.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt