netdev - Re: [PATCH v1 net 2/2] dccp/tcp: Call security_inet_conn

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Message-ID: <CAHC9VhTrm2shkh=FHcjnqFpDLFCoBwGfsyoSuDH3UFSOeZt+HA@mail.gmail.com>
Date: Mon, 30 Oct 2023 17:12:33 -0400
From: Paul Moore <paul@...l-moore.com>
To: Kuniyuki Iwashima <kuniyu@...zon.com>
Cc: "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, David Ahern <dsahern@...nel.org>, 
	Kuniyuki Iwashima <kuni1840@...il.com>, netdev@...r.kernel.org, dccp@...r.kernel.org, 
	Huw Davies <huw@...eweavers.com>, linux-security-module@...r.kernel.org
Subject: Re: [PATCH v1 net 2/2] dccp/tcp: Call security_inet_conn_request()
 after setting IPv6 addresses.

On Mon, Oct 30, 2023 at 4:12 PM Kuniyuki Iwashima <kuniyu@...zon.com> wrote:
>
> Initially, commit 4237c75c0a35 ("[MLSXFRM]: Auto-labeling of child
> sockets") introduced security_inet_conn_request() in some functions
> where reqsk is allocated.  The hook is added just after the allocation,
> so reqsk's IPv6 remote address was not initialised then.
>
> However, SELinux/Smack started to read it in netlbl_req_setattr()
> after commit e1adea927080 ("calipso: Allow request sockets to be
> relabelled by the lsm.").
>
> Commit 284904aa7946 ("lsm: Relocate the IPv4 security_inet_conn_request()
> hooks") fixed that kind of issue only in TCPv4 because IPv6 labeling was
> not supported at that time.  Finally, the same issue was introduced again
> in IPv6.
>
> Let's apply the same fix on DCCPv6 and TCPv6.
>
> Fixes: e1adea927080 ("calipso: Allow request sockets to be relabelled by the lsm.")
> Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.com>
> ---
> Cc: Huw Davies <huw@...eweavers.com>
> Cc: Paul Moore <paul@...l-moore.com>
> ---
>  net/dccp/ipv6.c       | 6 +++---
>  net/ipv6/syncookies.c | 7 ++++---
>  2 files changed, 7 insertions(+), 6 deletions(-)

Thanks for catching this and submitting a patch!

It seems like we should also update dccp_v4_conn_request(), what do you think?

> diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
> index 8d344b219f84..4550b680665a 100644
> --- a/net/dccp/ipv6.c
> +++ b/net/dccp/ipv6.c
> @@ -360,15 +360,15 @@ static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
>         if (dccp_parse_options(sk, dreq, skb))
>                 goto drop_and_free;
>
> -       if (security_inet_conn_request(sk, skb, req))
> -               goto drop_and_free;
> -
>         ireq = inet_rsk(req);
>         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
>         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
>         ireq->ireq_family = AF_INET6;
>         ireq->ir_mark = inet_request_mark(sk, skb);
>
> +       if (security_inet_conn_request(sk, skb, req))
> +               goto drop_and_free;
> +
>         if (ipv6_opt_accepted(sk, skb, IP6CB(skb)) ||
>             np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
>             np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
> diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
> index 500f6ed3b8cf..12eedc6ca2cc 100644
> --- a/net/ipv6/syncookies.c
> +++ b/net/ipv6/syncookies.c
> @@ -181,14 +181,15 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
>         treq = tcp_rsk(req);
>         treq->tfo_listener = false;
>
> -       if (security_inet_conn_request(sk, skb, req))
> -               goto out_free;
> -
>         req->mss = mss;
>         ireq->ir_rmt_port = th->source;
>         ireq->ir_num = ntohs(th->dest);
>         ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
>         ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
> +
> +       if (security_inet_conn_request(sk, skb, req))
> +               goto out_free;
> +
>         if (ipv6_opt_accepted(sk, skb, &TCP_SKB_CB(skb)->header.h6) ||
>             np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
>             np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
> --
> 2.30.2

-- 
paul-moore.com