Re: KASAN: stack-out-of-bounds Read in xfrm_selector_match (2)

[Steffen Klassert]

On Thu, Sep 24, 2020 at 05:43:51PM +1000, Herbert Xu wrote:
> 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 sure it can be fixed to work with either ipv4 or ipv6.
If I understand that right, it should be possible to talk
ipv4 and ipv6 through that socket, but the policy will
accept only one address family.

> I'm working on a fix.

Thanks!