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Message-ID: <20171031170606.GD3675@localhost.localdomain>
Date: Tue, 31 Oct 2017 15:06:06 -0200
From: Marcelo Ricardo Leitner <marcelo.leitner@...il.com>
To: Richard Haines <richard_c_haines@...nternet.com>
Cc: selinux@...ho.nsa.gov, netdev@...r.kernel.org,
linux-sctp@...r.kernel.org, linux-security-module@...r.kernel.org,
paul@...l-moore.com, vyasevich@...il.com, nhorman@...driver.com,
sds@...ho.nsa.gov, eparis@...isplace.org
Subject: Re: [RFC PATCH 2/5] sctp: Add ip option support
Hello,
On Tue, Oct 17, 2017 at 02:58:06PM +0100, Richard Haines wrote:
> Add ip option support to allow LSM security modules to utilise CIPSO/IPv4
> and CALIPSO/IPv6 services.
>
> Signed-off-by: Richard Haines <richard_c_haines@...nternet.com>
> ---
> include/net/sctp/structs.h | 2 ++
> net/sctp/chunk.c | 7 ++++---
> net/sctp/ipv6.c | 37 ++++++++++++++++++++++++++++++-------
> net/sctp/output.c | 3 ++-
> net/sctp/protocol.c | 36 ++++++++++++++++++++++++++++++++++++
> net/sctp/socket.c | 5 ++++-
> 6 files changed, 78 insertions(+), 12 deletions(-)
>
> diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
> index 5ab29af..7767577 100644
> --- a/include/net/sctp/structs.h
> +++ b/include/net/sctp/structs.h
> @@ -461,6 +461,7 @@ struct sctp_af {
> void (*ecn_capable)(struct sock *sk);
> __u16 net_header_len;
> int sockaddr_len;
> + int (*ip_options_len)(struct sock *sk);
> sa_family_t sa_family;
> struct list_head list;
> };
> @@ -485,6 +486,7 @@ struct sctp_pf {
> int (*addr_to_user)(struct sctp_sock *sk, union sctp_addr *addr);
> void (*to_sk_saddr)(union sctp_addr *, struct sock *sk);
> void (*to_sk_daddr)(union sctp_addr *, struct sock *sk);
> + void (*copy_ip_options)(struct sock *sk, struct sock *newsk);
> struct sctp_af *af;
> };
>
> diff --git a/net/sctp/chunk.c b/net/sctp/chunk.c
> index 1323d41..e49e240 100644
> --- a/net/sctp/chunk.c
> +++ b/net/sctp/chunk.c
> @@ -153,7 +153,6 @@ static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chu
> chunk->msg = msg;
> }
>
> -
> /* A data chunk can have a maximum payload of (2^16 - 20). Break
> * down any such message into smaller chunks. Opportunistically, fragment
> * the chunks down to the current MTU constraints. We may get refragmented
> @@ -190,7 +189,10 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
> */
> max_data = asoc->pathmtu -
> sctp_sk(asoc->base.sk)->pf->af->net_header_len -
^^^^^^^^
> - sizeof(struct sctphdr) - sizeof(struct sctp_data_chunk);
> + sizeof(struct sctphdr) - sizeof(struct sctp_data_chunk) -
> + sctp_sk(asoc->base.sk)->pf->af->
^^^^^^^^
> + ip_options_len(asoc->base.sk);
Please add a var for sctp_sk(asoc->base.sk)->pf->af. That should also
help to not break the dereferencing into multiple lines.
> +
> max_data = SCTP_TRUNC4(max_data);
>
> /* If the the peer requested that we authenticate DATA chunks
> @@ -210,7 +212,6 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
>
> /* Set first_len and then account for possible bundles on first frag */
> first_len = max_data;
> -
> /* Check to see if we have a pending SACK and try to let it be bundled
> * with this message. Do this if we don't have any data queued already.
> * To check that, look at out_qlen and retransmit list.
> diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
> index a4b6ffb..49c9011 100644
> --- a/net/sctp/ipv6.c
> +++ b/net/sctp/ipv6.c
> @@ -423,6 +423,33 @@ static void sctp_v6_copy_addrlist(struct list_head *addrlist,
> rcu_read_unlock();
> }
>
> +/* Copy over any ip options */
> +static void sctp_v6_copy_ip_options(struct sock *sk, struct sock *newsk)
> +{
> + struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
> + struct ipv6_txoptions *opt;
> +
> + newnp = inet6_sk(newsk);
> +
> + rcu_read_lock();
> + opt = rcu_dereference(np->opt);
> + if (opt)
> + opt = ipv6_dup_options(newsk, opt);
> + RCU_INIT_POINTER(newnp->opt, opt);
> + rcu_read_unlock();
> +}
> +
> +/* Account for the IP options */
> +static int sctp_v6_ip_options_len(struct sock *sk)
> +{
> + struct ipv6_pinfo *inet6 = inet6_sk(sk);
> +
> + if (inet6->opt)
> + return inet6->opt->opt_flen + inet6->opt->opt_nflen;
Seems we need RCU protection here.
And please add a var for inet6->opt.
> + else
> + return 0;
> +}
> +
> /* Initialize a sockaddr_storage from in incoming skb. */
> static void sctp_v6_from_skb(union sctp_addr *addr, struct sk_buff *skb,
> int is_saddr)
> @@ -662,7 +689,6 @@ static struct sock *sctp_v6_create_accept_sk(struct sock *sk,
> struct sock *newsk;
> struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
> struct sctp6_sock *newsctp6sk;
> - struct ipv6_txoptions *opt;
>
> newsk = sk_alloc(sock_net(sk), PF_INET6, GFP_KERNEL, sk->sk_prot, kern);
> if (!newsk)
> @@ -685,12 +711,7 @@ static struct sock *sctp_v6_create_accept_sk(struct sock *sk,
> newnp->ipv6_ac_list = NULL;
> newnp->ipv6_fl_list = NULL;
>
> - rcu_read_lock();
> - opt = rcu_dereference(np->opt);
> - if (opt)
> - opt = ipv6_dup_options(newsk, opt);
> - RCU_INIT_POINTER(newnp->opt, opt);
> - rcu_read_unlock();
> + sctp_v6_copy_ip_options(sk, newsk);
>
> /* Initialize sk's sport, dport, rcv_saddr and daddr for getsockname()
> * and getpeername().
> @@ -1033,6 +1054,7 @@ static struct sctp_af sctp_af_inet6 = {
> .ecn_capable = sctp_v6_ecn_capable,
> .net_header_len = sizeof(struct ipv6hdr),
> .sockaddr_len = sizeof(struct sockaddr_in6),
> + .ip_options_len = sctp_v6_ip_options_len,
> #ifdef CONFIG_COMPAT
> .compat_setsockopt = compat_ipv6_setsockopt,
> .compat_getsockopt = compat_ipv6_getsockopt,
> @@ -1051,6 +1073,7 @@ static struct sctp_pf sctp_pf_inet6 = {
> .addr_to_user = sctp_v6_addr_to_user,
> .to_sk_saddr = sctp_v6_to_sk_saddr,
> .to_sk_daddr = sctp_v6_to_sk_daddr,
> + .copy_ip_options = sctp_v6_copy_ip_options,
> .af = &sctp_af_inet6,
> };
>
> diff --git a/net/sctp/output.c b/net/sctp/output.c
> index 9d85049..85bcd5b 100644
> --- a/net/sctp/output.c
> +++ b/net/sctp/output.c
> @@ -151,7 +151,8 @@ void sctp_packet_init(struct sctp_packet *packet,
> INIT_LIST_HEAD(&packet->chunk_list);
> if (asoc) {
> struct sctp_sock *sp = sctp_sk(asoc->base.sk);
> - overhead = sp->pf->af->net_header_len;
> + overhead = sp->pf->af->net_header_len +
> + sp->pf->af->ip_options_len(asoc->base.sk);
Here you may also add a var for sp->pf->af.
> } else {
> overhead = sizeof(struct ipv6hdr);
> }
> diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
> index 989a900..a9e54ac 100644
> --- a/net/sctp/protocol.c
> +++ b/net/sctp/protocol.c
> @@ -237,6 +237,38 @@ int sctp_copy_local_addr_list(struct net *net, struct sctp_bind_addr *bp,
> return error;
> }
>
> +/* Copy over any ip options */
> +static void sctp_v4_copy_ip_options(struct sock *sk, struct sock *newsk)
> +{
> + struct inet_sock *newinet, *inet = inet_sk(sk);
> + struct ip_options_rcu *inet_opt, *newopt = NULL;
> +
> + newinet = inet_sk(newsk);
> +
> + rcu_read_lock();
> + inet_opt = rcu_dereference(inet->inet_opt);
> + if (inet_opt) {
> + newopt = sock_kmalloc(newsk, sizeof(*inet_opt) +
> + inet_opt->opt.optlen, GFP_ATOMIC);
> + if (newopt)
> + memcpy(newopt, inet_opt, sizeof(*inet_opt) +
> + inet_opt->opt.optlen);
> + }
> + RCU_INIT_POINTER(newinet->inet_opt, newopt);
> + rcu_read_unlock();
> +}
> +
> +/* Account for the IP options */
> +static int sctp_v4_ip_options_len(struct sock *sk)
> +{
> + struct inet_sock *inet = inet_sk(sk);
> +
> + if (inet->inet_opt)
> + return inet->inet_opt->opt.optlen;
> + else
> + return 0;
> +}
> +
> /* Initialize a sctp_addr from in incoming skb. */
> static void sctp_v4_from_skb(union sctp_addr *addr, struct sk_buff *skb,
> int is_saddr)
> @@ -590,6 +622,8 @@ static struct sock *sctp_v4_create_accept_sk(struct sock *sk,
> sctp_copy_sock(newsk, sk, asoc);
> sock_reset_flag(newsk, SOCK_ZAPPED);
>
> + sctp_v4_copy_ip_options(sk, newsk);
> +
> newinet = inet_sk(newsk);
>
> newinet->inet_daddr = asoc->peer.primary_addr.v4.sin_addr.s_addr;
> @@ -1008,6 +1042,7 @@ static struct sctp_pf sctp_pf_inet = {
> .addr_to_user = sctp_v4_addr_to_user,
> .to_sk_saddr = sctp_v4_to_sk_saddr,
> .to_sk_daddr = sctp_v4_to_sk_daddr,
> + .copy_ip_options = sctp_v4_copy_ip_options,
> .af = &sctp_af_inet
> };
>
> @@ -1092,6 +1127,7 @@ static struct sctp_af sctp_af_inet = {
> .ecn_capable = sctp_v4_ecn_capable,
> .net_header_len = sizeof(struct iphdr),
> .sockaddr_len = sizeof(struct sockaddr_in),
> + .ip_options_len = sctp_v4_ip_options_len,
> #ifdef CONFIG_COMPAT
> .compat_setsockopt = compat_ip_setsockopt,
> .compat_getsockopt = compat_ip_getsockopt,
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index 8d76086..70355a0 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -3124,6 +3124,7 @@ static int sctp_setsockopt_maxseg(struct sock *sk, char __user *optval, unsigned
> if (asoc) {
> if (val == 0) {
> val = asoc->pathmtu;
> + val -= sp->pf->af->ip_options_len(asoc->base.sk);
> val -= sp->pf->af->net_header_len;
Also here. May even be inside the if() block.
Thanks
> val -= sizeof(struct sctphdr) +
> sizeof(struct sctp_data_chunk);
> @@ -4917,9 +4918,11 @@ int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp)
> sctp_copy_sock(sock->sk, sk, asoc);
>
> /* Make peeled-off sockets more like 1-1 accepted sockets.
> - * Set the daddr and initialize id to something more random
> + * Set the daddr and initialize id to something more random and also
> + * copy over any ip options.
> */
> sp->pf->to_sk_daddr(&asoc->peer.primary_addr, sk);
> + sp->pf->copy_ip_options(sk, sock->sk);
>
> /* Populate the fields of the newsk from the oldsk and migrate the
> * asoc to the newsk.
> --
> 2.13.6
>
> --
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