netdev - Re: [PATCH net] sctp: fail if no bound addresses can be used for a given scope

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Message-ID: <Y9CUPsuuYgdr/g+s@t14s.localdomain>
Date:   Tue, 24 Jan 2023 23:30:22 -0300
From:   Marcelo Ricardo Leitner <marcelo.leitner@...il.com>
To:     Jakub Kicinski <kuba@...nel.org>
Cc:     netdev@...r.kernel.org, linux-sctp@...r.kernel.org,
        Xin Long <lucien.xin@...il.com>,
        Pietro Borrello <borrello@...g.uniroma1.it>
Subject: Re: [PATCH net] sctp: fail if no bound addresses can be used for a
 given scope

On Tue, Jan 24, 2023 at 06:14:16PM -0800, Jakub Kicinski wrote:
> On Mon, 23 Jan 2023 14:59:33 -0300 Marcelo Ricardo Leitner wrote:
> > Currently, if you bind the socket to something like:
> >         servaddr.sin6_family = AF_INET6;
> >         servaddr.sin6_port = htons(0);
> >         servaddr.sin6_scope_id = 0;
> >         inet_pton(AF_INET6, "::1", &servaddr.sin6_addr);
> > 
> > And then request a connect to:
> >         connaddr.sin6_family = AF_INET6;
> >         connaddr.sin6_port = htons(20000);
> >         connaddr.sin6_scope_id = if_nametoindex("lo");
> >         inet_pton(AF_INET6, "fe88::1", &connaddr.sin6_addr);
> > 
> > What the stack does is:
> >  - bind the socket
> >  - create a new asoc
> >  - to handle the connect
> >    - copy the addresses that can be used for the given scope
> >    - try to connect
> > 
> > But the copy returns 0 addresses, and the effect is that it ends up
> > trying to connect as if the socket wasn't bound, which is not the
> > desired behavior. This unexpected behavior also allows KASLR leaks
> > through SCTP diag interface.
> > 
> > The fix here then is, if when trying to copy the addresses that can
> > be used for the scope used in connect() it returns 0 addresses, bail
> > out. This is what TCP does with a similar reproducer.
> > 
> > Reported-by: Pietro Borrello <borrello@...g.uniroma1.it>
> > Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@...il.com>
> 
> Fixes tag?

Lost in Narnia again, I suppose. :)

Ok, I had forgot it, but now checking, it predates git.
What should I have used in this case again please? Perhaps just:

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")