From: Jakub Kicinski <kuba@kernel.org>
To: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Cc: netdev@vger.kernel.org, linux-sctp@vger.kernel.org,
Xin Long <lucien.xin@gmail.com>,
Pietro Borrello <borrello@diag.uniroma1.it>
Subject: Re: [PATCH net] sctp: fail if no bound addresses can be used for a given scope
Date: Tue, 24 Jan 2023 18:14:16 -0800 [thread overview]
Message-ID: <20230124181416.6218adb7@kernel.org> (raw)
In-Reply-To: <9fcd182f1099f86c6661f3717f63712ddd1c676c.1674496737.git.marcelo.leitner@gmail.com>
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@diag.uniroma1.it>
> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Fixes tag?
next prev parent reply other threads:[~2023-01-25 2:14 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-23 17:59 [PATCH net] sctp: fail if no bound addresses can be used for a given scope Marcelo Ricardo Leitner
2023-01-23 19:57 ` Xin Long
2023-01-25 2:14 ` Jakub Kicinski [this message]
2023-01-25 2:30 ` Marcelo Ricardo Leitner
2023-01-25 2:32 ` Jakub Kicinski
2023-01-25 2:33 ` Marcelo Ricardo Leitner
2023-01-25 2:40 ` patchwork-bot+netdevbpf
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