From: Paul Moore <paul@paul-moore.com>
To: Nazarov Sergey <s-nazarov@yandex.ru>
Cc: "linux-security-module@vger.kernel.org"
<linux-security-module@vger.kernel.org>,
"selinux@vger.kernel.org" <selinux@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
Casey Schaufler <casey@schaufler-ca.com>
Subject: Re: Kernel memory corruption in CIPSO labeled TCP packets processing.
Date: Wed, 30 Jan 2019 21:10:16 -0500 [thread overview]
Message-ID: <CAHC9VhQcrnXmjcVw_ppwM-fGcwhJq9SafTnZKjgpQpxK0ie+Jw@mail.gmail.com> (raw)
In-Reply-To: <3191601548853902@myt6-23299ba78d64.qloud-c.yandex.net>
On Wed, Jan 30, 2019 at 8:11 AM Nazarov Sergey <s-nazarov@yandex.ru> wrote:
> 30.01.2019, 01:42, "Paul Moore" <paul@paul-moore.com>:
> > There are several cases where the stack ends up calling icmp_send()
> > after the skb has been through ip_options_compile(), that should be
> > okay.
> >
> > --
> > paul moore
> > www.paul-moore.com
>
> In those cases precompiled ip_options struct used, without the need to reuse ip_options_compile.
> I think, for error ICMP packet, we can discard all other options except CIPSO. It will be better, than
> send packet, contains wrong option's data. Modified patch 2:
> ---
> net/ipv4/cipso_ipv4.c | 24 ++++++++++++++++++++++--
> 1 files changed, 22 insertions(+), 2 deletions(-)
This isn't how the rest of the stack works, look at
ip_local_deliver_finish() for one example. Perhaps the behavior you
are proposing is correct, but please show me where in the various RFC
specs it is defined so that I can better understand why it should work
this way.
> diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
> index 777fa3b..797826c 100644
> --- a/net/ipv4/cipso_ipv4.c
> +++ b/net/ipv4/cipso_ipv4.c
> @@ -1735,13 +1735,33 @@ int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option)
> */
> void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway)
> {
> + struct ip_options opt;
> + unsigned char *optptr;
> +
> if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES)
> return;
>
> + /*
> + * We might be called above the IP layer,
> + * so we can not use icmp_send and IPCB here.
> + *
> + * For the generated ICMP packet, we create a
> + * temporary ip _options structure, contains
> + * the CIPSO option only, since the other options data
> + * could be modified when the original packet receiving.
> + */
> +
> + memset(&opt, 0, sizeof(struct ip_options));
> + optptr = cipso_v4_optptr(skb);
> + if (optptr) {
> + opt.optlen = optptr[1];
> + opt.cipso = optptr - skb_network_header(skb);
> + }
> +
> if (gateway)
> - icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0);
> + __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0, &opt);
> else
> - icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0);
> + __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0, &opt);
> }
>
> /**
>
--
paul moore
www.paul-moore.com
next prev parent reply other threads:[~2019-01-31 2:10 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-15 17:06 Kernel memory corruption in CIPSO labeled TCP packets processing Nazarov Sergey
2019-01-15 17:55 ` Casey Schaufler
2019-01-15 19:52 ` Paul Moore
2019-01-18 14:53 ` Paul Moore
2019-01-18 16:34 ` Nazarov Sergey
2019-01-18 17:17 ` Paul Moore
2019-01-21 17:11 ` Nazarov Sergey
2019-01-22 16:49 ` Paul Moore
2019-01-22 17:35 ` Nazarov Sergey
2019-01-22 17:48 ` Paul Moore
2019-01-24 14:46 ` Nazarov Sergey
2019-01-25 16:45 ` Paul Moore
2019-01-28 13:10 ` Nazarov Sergey
2019-01-28 22:18 ` Paul Moore
2019-01-29 7:23 ` Nazarov Sergey
2019-01-29 22:42 ` Paul Moore
2019-01-30 13:11 ` Nazarov Sergey
2019-01-31 2:10 ` Paul Moore [this message]
2019-01-31 13:20 ` Nazarov Sergey
2019-02-11 20:37 ` Paul Moore
2019-02-11 21:21 ` Nazarov Sergey
2019-02-11 23:43 ` Paul Moore
2019-02-12 15:10 ` [PATCH] NETWORKING: avoid use IPCB in cipso_v4_error Nazarov Sergey
2019-02-13 21:41 ` Paul Moore
2019-02-14 18:00 ` Nazarov Sergey
2019-02-14 18:59 ` Stephen Smalley
2019-02-14 16:43 ` David Miller
2019-02-14 18:14 ` Nazarov Sergey
2019-02-15 19:02 ` Paul Moore
2019-02-15 20:00 ` David Miller
2019-02-15 20:04 ` Paul Moore
2019-02-18 13:39 ` Nazarov Sergey
2019-02-19 1:25 ` David Miller
2019-02-22 16:35 ` Nazarov Sergey
2019-02-22 17:39 ` [PATCH v2 0/2] " Nazarov Sergey
2019-02-25 1:33 ` David Miller
2019-02-25 16:24 ` [PATCH v2 1/2] " Nazarov Sergey
2019-02-25 22:07 ` Paul Moore
2019-02-25 22:33 ` David Miller
2019-02-25 23:30 ` Paul Moore
2019-02-25 16:27 ` [PATCH v2 2/2] " Nazarov Sergey
2019-02-25 22:06 ` Paul Moore
2019-02-25 22:34 ` David Miller
2019-02-22 17:43 ` [PATCH v2 1/2] " Nazarov Sergey
2019-02-22 17:50 ` [PATCH v2 2/2] " Nazarov Sergey
2019-02-25 1:33 ` [PATCH] " David Miller
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