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Message-ID: <1509571753.2954.3.camel@btinternet.com>
Date: Wed, 01 Nov 2017 21:29:13 +0000
From: Richard Haines <richard_c_haines@...nternet.com>
To: Marcelo Ricardo Leitner <marcelo.leitner@...il.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
On Tue, 2017-10-31 at 15:06 -0200, Marcelo Ricardo Leitner wrote:
> 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.
DONE
>
> > +
> > 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.
I've changed and tested the following:
/* Account for the IP options */
static int sctp_v6_ip_options_len(struct sock *sk)
{
struct ipv6_pinfo *np = inet6_sk(sk);
struct ipv6_txoptions *opt;
int len = 0;
rcu_read_lock();
opt = rcu_dereference(np->opt);
if (opt)
len = opt->opt_flen + opt->opt_nflen;
rcu_read_unlock();
return len;
}
>
> > + 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.
DONE
>
> > } 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.
DONE
>
> 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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> > sctp" in
> > the body of a message to majordomo@...r.kernel.org
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> >
>
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