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pf: support SCTP multihoming

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SCTP may announce additional IP addresses it'll use in the INIT/INIT_ACK
chunks, or in ASCONF chunks at any time during the connection. Parse these
parameters, evaluate the ruleset for the new connection and if allowed
create the corresponding states.

MFC after:	3 weeks
Sponsored by:	Orange Business Services
Differential Revision:	https://reviews.freebsd.org/D41637
This commit is contained in:
Kristof Provost 2023-08-02 19:05:00 +02:00
parent 5449d0144d
commit 10aa9ddb4d
3 changed files with 231 additions and 11 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

22
sys/net/pfvar.h
View file

@ -1531,6 +1531,9 @@ struct pfi_kkif {
#define PFI_IFLAG_SKIP 0x0100 /* skip filtering on interface */
#ifdef _KERNEL
struct pf_sctp_multihome_job;
TAILQ_HEAD(pf_sctp_multihome_jobs, pf_sctp_multihome_job);
struct pf_pdesc {
struct {
int done;
@ -1578,10 +1581,22 @@ struct pf_pdesc {
#define PFDESC_SCTP_SHUTDOWN 0x0010
#define PFDESC_SCTP_SHUTDOWN_COMPLETE 0x0020
#define PFDESC_SCTP_DATA 0x0040
#define PFDESC_SCTP_OTHER 0x0080
#define PFDESC_SCTP_ASCONF 0x0080
#define PFDESC_SCTP_OTHER 0x0100
u_int16_t sctp_flags;
u_int32_t sctp_initiate_tag;
struct pf_sctp_multihome_jobs sctp_multihome_jobs;
};
struct pf_sctp_multihome_job {
TAILQ_ENTRY(pf_sctp_multihome_job) next;
struct pf_pdesc pd;
struct pf_addr src;
struct pf_addr dst;
struct mbuf *m;
};
#endif
/* flags for RDR options */
@ -2249,6 +2264,11 @@ void pf_addr_inc(struct pf_addr *, sa_family_t);
int pf_refragment6(struct ifnet *, struct mbuf **, struct m_tag *, bool);
#endif /* INET6 */
int pf_multihome_scan_init(struct mbuf *, int, int, struct pf_pdesc *,
struct pfi_kkif *);
int pf_multihome_scan_asconf(struct mbuf *, int, int, struct pf_pdesc *,
struct pfi_kkif *);
u_int32_t pf_new_isn(struct pf_kstate *);
void *pf_pull_hdr(struct mbuf *, int, void *, int, u_short *, u_short *,
sa_family_t);

186
sys/netpfil/pf/pf.c
View file

@ -126,6 +126,8 @@ SDT_PROBE_DEFINE4(pf, ip, test6, done, "int", "int", "struct pf_krule *",
SDT_PROBE_DEFINE5(pf, ip, state, lookup, "struct pfi_kkif *",
"struct pf_state_key_cmp *", "int", "struct pf_pdesc *",
"struct pf_kstate *");
SDT_PROBE_DEFINE4(pf, sctp, multihome, test, "struct pfi_kkif *",
"struct pf_krule *", "struct mbuf *", "int");
SDT_PROBE_DEFINE3(pf, eth, test_rule, entry, "int", "struct ifnet *",
"struct mbuf *");
@ -307,6 +309,8 @@ static int pf_test_state_udp(struct pf_kstate **,
static int pf_test_state_icmp(struct pf_kstate **,
struct pfi_kkif *, struct mbuf *, int,
void *, struct pf_pdesc *, u_short *);
static void pf_sctp_multihome_delayed(struct pf_pdesc *, int,
struct pfi_kkif *, struct pf_kstate *);
static int pf_test_state_sctp(struct pf_kstate **,
struct pfi_kkif *, struct mbuf *, int,
void *, struct pf_pdesc *, u_short *);
@ -5912,6 +5916,174 @@ pf_test_state_sctp(struct pf_kstate **state, struct pfi_kkif *kif,
return (PF_PASS);
}
static void
pf_sctp_multihome_delayed(struct pf_pdesc *pd, int off, struct pfi_kkif *kif,
struct pf_kstate *s)
{
struct pf_sctp_multihome_job *j, *tmp;
int action;;
struct pf_kstate *sm = NULL;
struct pf_krule *ra = NULL;
struct pf_krule *r = &V_pf_default_rule;
struct pf_kruleset *rs = NULL;
PF_RULES_RLOCK_TRACKER;
TAILQ_FOREACH_SAFE(j, &pd->sctp_multihome_jobs, next, tmp) {
PF_RULES_RLOCK();
action = pf_test_rule(&r, &sm, kif,
j->m, off, &j->pd, &ra, &rs, NULL);
PF_RULES_RUNLOCK();
SDT_PROBE4(pf, sctp, multihome, test, kif, r, j->m, action);
if (sm)
PF_STATE_UNLOCK(sm);
free(j, M_PFTEMP);
}
}
static int
pf_multihome_scan(struct mbuf *m, int start, int len, struct pf_pdesc *pd,
struct pfi_kkif *kif)
{
int off = 0;
struct pf_sctp_multihome_job *job;
while (off < len) {
struct sctp_paramhdr h;
if (!pf_pull_hdr(m, start + off, &h, sizeof(h), NULL, NULL,
pd->af))
return (PF_DROP);
/* Parameters are at least 4 bytes. */
if (ntohs(h.param_length) < 4)
return (PF_DROP);
switch (ntohs(h.param_type)) {
case SCTP_IPV4_ADDRESS: {
struct in_addr t;
if (ntohs(h.param_length) !=
(sizeof(struct sctp_paramhdr) + sizeof(t)))
return (PF_DROP);
if (!pf_pull_hdr(m, start + off + sizeof(h), &t, sizeof(t),
NULL, NULL, pd->af))
return (PF_DROP);
/*
* Avoid duplicating states. We'll already have
* created a state based on the source address of
* the packet, but SCTP endpoints may also list this
* address again in the INIT(_ACK) parameters.
*/
if (t.s_addr == pd->src->v4.s_addr)
break;
if (in_nullhost(t))
t.s_addr = pd->src->v4.s_addr;
/*
* We hold the state lock (idhash) here, which means
* that we can't acquire the keyhash, or we'll get a
* LOR (and potentially double-lock things too). We also
* can't release the state lock here, so instead we'll
* enqueue this for async handling.
* There's a relatively small race here, in that a
* packet using the new addresses could arrive already,
* but that's just though luck for it.
*/
job = malloc(sizeof(*job), M_PFTEMP, M_NOWAIT | M_ZERO);
if (! job)
return (PF_DROP);
memcpy(&job->pd, pd, sizeof(*pd));
// New source address!
memcpy(&job->src, &t, sizeof(t));
job->pd.src = &job->src;
memcpy(&job->dst, pd->dst, sizeof(job->dst));
job->pd.dst = &job->dst;
job->m = m;
TAILQ_INSERT_TAIL(&pd->sctp_multihome_jobs, job, next);
break;
}
#ifdef INET6
case SCTP_IPV6_ADDRESS: {
struct in6_addr t;
if (ntohs(h.param_length) !=
(sizeof(struct sctp_paramhdr) + sizeof(t)))
return (PF_DROP);
if (!pf_pull_hdr(m, start + off + sizeof(h), &t, sizeof(t),
NULL, NULL, pd->af))
return (PF_DROP);
if (memcmp(&t, &pd->src->v6, sizeof(t)) == 0)
break;
if (memcmp(&t, &in6addr_any, sizeof(t)) == 0)
memcpy(&t, &pd->src->v6, sizeof(t));
job = malloc(sizeof(*job), M_PFTEMP, M_NOWAIT | M_ZERO);
if (! job)
return (PF_DROP);
memcpy(&job->pd, pd, sizeof(*pd));
memcpy(&job->src, &t, sizeof(t));
job->pd.src = &job->src;
memcpy(&job->dst, pd->dst, sizeof(job->dst));
job->pd.dst = &job->dst;
job->m = m;
TAILQ_INSERT_TAIL(&pd->sctp_multihome_jobs, job, next);
break;
}
#endif
case SCTP_ADD_IP_ADDRESS: {
int ret;
struct sctp_asconf_paramhdr ah;
if (!pf_pull_hdr(m, start + off, &ah, sizeof(ah),
NULL, NULL, pd->af))
return (PF_DROP);
ret = pf_multihome_scan(m, start + off + sizeof(ah),
ntohs(ah.ph.param_length) - sizeof(ah), pd, kif);
if (ret != PF_PASS)
return (ret);
break;
}
default:
break;
}
off += roundup(ntohs(h.param_length), 4);
}
return (PF_PASS);
}
int
pf_multihome_scan_init(struct mbuf *m, int start, int len, struct pf_pdesc *pd,
struct pfi_kkif *kif)
{
start += sizeof(struct sctp_init_chunk);
len -= sizeof(struct sctp_init_chunk);
return (pf_multihome_scan(m, start, len, pd, kif));
}
int
pf_multihome_scan_asconf(struct mbuf *m, int start, int len,
struct pf_pdesc *pd, struct pfi_kkif *kif)
{
start += sizeof(struct sctp_asconf_chunk);
len -= sizeof(struct sctp_asconf_chunk);
return (pf_multihome_scan(m, start, len, pd, kif));
}
static int
pf_test_state_icmp(struct pf_kstate **state, struct pfi_kkif *kif,
struct mbuf *m, int off, void *h, struct pf_pdesc *pd, u_short *reason)
@ -7412,6 +7584,7 @@ pf_test(int dir, int pflags, struct ifnet *ifp, struct mbuf **m0,
}
memset(&pd, 0, sizeof(pd));
TAILQ_INIT(&pd.sctp_multihome_jobs);
if (default_actions != NULL)
memcpy(&pd.act, default_actions, sizeof(pd.act));
pd.pf_mtag = pf_find_mtag(m);
@ -7613,6 +7786,8 @@ pf_test(int dir, int pflags, struct ifnet *ifp, struct mbuf **m0,
pd.act.log |= PF_LOG_FORCE;
goto done;
}
pd.p_len = pd.tot_len - off;
pd.sport = &pd.hdr.sctp.src_port;
pd.dport = &pd.hdr.sctp.dest_port;
if (pd.hdr.sctp.src_port == 0 || pd.hdr.sctp.dest_port == 0) {
@ -7896,7 +8071,7 @@ pf_test(int dir, int pflags, struct ifnet *ifp, struct mbuf **m0,
/* pf_route() returns unlocked. */
if (rt) {
pf_route(m0, r, kif->pfik_ifp, s, &pd, inp);
return (action);
goto out;
}
if (pf_dummynet(&pd, s, r, m0) != 0) {
action = PF_DROP;
@ -7910,6 +8085,9 @@ pf_test(int dir, int pflags, struct ifnet *ifp, struct mbuf **m0,
if (s)
PF_STATE_UNLOCK(s);
out:
pf_sctp_multihome_delayed(&pd, off, kif, s);
return (action);
}
#endif /* INET */
@ -7959,6 +8137,7 @@ pf_test6(int dir, int pflags, struct ifnet *ifp, struct mbuf **m0, struct inpcb
}
memset(&pd, 0, sizeof(pd));
TAILQ_INIT(&pd.sctp_multihome_jobs);
if (default_actions != NULL)
memcpy(&pd.act, default_actions, sizeof(pd.act));
pd.pf_mtag = pf_find_mtag(m);
@ -8441,7 +8620,7 @@ pf_test6(int dir, int pflags, struct ifnet *ifp, struct mbuf **m0, struct inpcb
/* pf_route6() returns unlocked. */
if (rt) {
pf_route6(m0, r, kif->pfik_ifp, s, &pd, inp);
return (action);
goto out;
}
if (pf_dummynet(&pd, s, r, m0) != 0) {
action = PF_DROP;
@ -8458,8 +8637,11 @@ pf_test6(int dir, int pflags, struct ifnet *ifp, struct mbuf **m0, struct inpcb
(mtag = m_tag_find(m, PACKET_TAG_PF_REASSEMBLED, NULL)) != NULL)
action = pf_refragment6(ifp, m0, mtag, pflags & PFIL_FWD);
out:
SDT_PROBE4(pf, ip, test6, done, action, reason, r, s);
pf_sctp_multihome_delayed(&pd, off, kif, s);
return (action);
}
#endif /* INET6 */

34
sys/netpfil/pf/pf_norm.c
View file

@ -2021,11 +2021,13 @@ pf_normalize_mss(struct mbuf *m, int off, struct pf_pdesc *pd)
}
static int
pf_scan_sctp(struct mbuf *m, int ipoff, int off, struct pf_pdesc *pd)
pf_scan_sctp(struct mbuf *m, int ipoff, int off, struct pf_pdesc *pd,
struct pfi_kkif *kif)
{
struct sctp_chunkhdr ch = { };
int chunk_off = sizeof(struct sctphdr);
int chunk_start;
int ret;
while (off + chunk_off < pd->tot_len) {
if (!pf_pull_hdr(m, off + chunk_off, &ch, sizeof(ch), NULL,
@ -2040,7 +2042,8 @@ pf_scan_sctp(struct mbuf *m, int ipoff, int off, struct pf_pdesc *pd)
chunk_off += roundup(ntohs(ch.chunk_length), 4);
switch (ch.chunk_type) {
case SCTP_INITIATION: {
case SCTP_INITIATION:
case SCTP_INITIATION_ACK: {
struct sctp_init_chunk init;
if (!pf_pull_hdr(m, off + chunk_start, &init,
@ -2064,17 +2067,24 @@ pf_scan_sctp(struct mbuf *m, int ipoff, int off, struct pf_pdesc *pd)
* RFC 9260, Section 3.1, INIT chunks MUST have zero
* verification tag.
*/
if (pd->hdr.sctp.v_tag != 0)
if (ch.chunk_type == SCTP_INITIATION &&
pd->hdr.sctp.v_tag != 0)
return (PF_DROP);
pd->sctp_initiate_tag = init.init.initiate_tag;
pd->sctp_flags |= PFDESC_SCTP_INIT;
if (ch.chunk_type == SCTP_INITIATION)
pd->sctp_flags |= PFDESC_SCTP_INIT;
else
pd->sctp_flags |= PFDESC_SCTP_INIT_ACK;
ret = pf_multihome_scan_init(m, off + chunk_start,
ntohs(init.ch.chunk_length), pd, kif);
if (ret != PF_PASS)
return (ret);
break;
}
case SCTP_INITIATION_ACK:
pd->sctp_flags |= PFDESC_SCTP_INIT_ACK;
break;
case SCTP_ABORT_ASSOCIATION:
pd->sctp_flags |= PFDESC_SCTP_ABORT;
break;
@ -2092,6 +2102,14 @@ pf_scan_sctp(struct mbuf *m, int ipoff, int off, struct pf_pdesc *pd)
case SCTP_DATA:
pd->sctp_flags |= PFDESC_SCTP_DATA;
break;
case SCTP_ASCONF:
pd->sctp_flags |= PFDESC_SCTP_ASCONF;
ret = pf_multihome_scan_asconf(m, off + chunk_start,
ntohs(ch.chunk_length), pd, kif);
if (ret != PF_PASS)
return (ret);
break;
default:
pd->sctp_flags |= PFDESC_SCTP_OTHER;
break;
@ -2133,7 +2151,7 @@ pf_normalize_sctp(int dir, struct pfi_kkif *kif, struct mbuf *m, int ipoff,
/* Unconditionally scan the SCTP packet, because we need to look for
* things like shutdown and asconf chunks. */
if (pf_scan_sctp(m, ipoff, off, pd) != PF_PASS)
if (pf_scan_sctp(m, ipoff, off, pd, kif) != PF_PASS)
goto sctp_drop;
r = TAILQ_FIRST(pf_main_ruleset.rules[PF_RULESET_SCRUB].active.ptr);