The branch main has been updated by kp:
URL:
https://cgit.FreeBSD.org/src/commit/?id=cd0169c9379c400ec75b77e87ca770e37f964276
commit cd0169c9379c400ec75b77e87ca770e37f964276
Author: Kristof Provost <k...@freebsd.org>
AuthorDate: 2025-06-21 09:13:22 +0000
Commit: Kristof Provost <k...@freebsd.org>
CommitDate: 2025-06-25 20:04:15 +0000
pf: limit extra SCTP states
For SCTP we create states for all combinations of endpoints, to allow
multihoming to work.
Malicious users could abuse this to fill our state table more easily
than they otherwise could, because we create states between all
combinations of endpoints. Limit this to no more than 8 extra endpoints
for each side of the connection.
MFC after: 2 weeks
Sponsored by: Orange Business Services
---
sys/netpfil/pf/pf.c | 11 +++++++++++
tests/sys/netpfil/pf/sctp.py | 28 ++++++++++++++++++++++++++++
2 files changed, 39 insertions(+)
diff --git a/sys/netpfil/pf/pf.c b/sys/netpfil/pf/pf.c
index 908f1b83e542..c162b3dd8b3c 100644
--- a/sys/netpfil/pf/pf.c
+++ b/sys/netpfil/pf/pf.c
@@ -205,6 +205,8 @@ VNET_DEFINE(size_t, pf_allrulecount);
VNET_DEFINE(struct pf_krule *, pf_rulemarker);
#endif
+#define PF_SCTP_MAX_ENDPOINTS 8
+
struct pf_sctp_endpoint;
RB_HEAD(pf_sctp_endpoints, pf_sctp_endpoint);
struct pf_sctp_source {
@@ -7297,6 +7299,7 @@ pf_sctp_multihome_add_addr(struct pf_pdesc *pd, struct
pf_addr *a, uint32_t v_ta
};
struct pf_sctp_source *i;
struct pf_sctp_endpoint *ep;
+ int count;
PF_SCTP_ENDPOINTS_LOCK();
@@ -7315,13 +7318,21 @@ pf_sctp_multihome_add_addr(struct pf_pdesc *pd, struct
pf_addr *a, uint32_t v_ta
}
/* Avoid inserting duplicates. */
+ count = 0;
TAILQ_FOREACH(i, &ep->sources, entry) {
+ count++;
if (pf_addr_cmp(&i->addr, a, pd->af) == 0) {
PF_SCTP_ENDPOINTS_UNLOCK();
return;
}
}
+ /* Limit the number of addresses per endpoint. */
+ if (count >= PF_SCTP_MAX_ENDPOINTS) {
+ PF_SCTP_ENDPOINTS_UNLOCK();
+ return;
+ }
+
i = malloc(sizeof(*i), M_PFTEMP, M_NOWAIT);
if (i == NULL) {
PF_SCTP_ENDPOINTS_UNLOCK();
diff --git a/tests/sys/netpfil/pf/sctp.py b/tests/sys/netpfil/pf/sctp.py
index 230dbae0d327..da42ce527195 100644
--- a/tests/sys/netpfil/pf/sctp.py
+++ b/tests/sys/netpfil/pf/sctp.py
@@ -426,6 +426,34 @@ class TestSCTP(VnetTestTemplate):
assert re.search(r"all sctp 192.0.2.4:.*192.0.2.3:1234", states)
assert re.search(r"all sctp 192.0.2.4:.*192.0.2.2:1234", states)
+ @pytest.mark.require_user("root")
+ def test_limit_addresses(self):
+ srv_vnet = self.vnet_map["vnet2"]
+
+ ifname = self.vnet_map["vnet1"].iface_alias_map["if1"].name
+ for i in range(0, 16):
+ ToolsHelper.print_output("/sbin/ifconfig %s inet alias
192.0.2.%d/24" % (ifname, 4 + i))
+
+ ToolsHelper.print_output("/sbin/pfctl -e")
+ ToolsHelper.pf_rules([
+ "block proto sctp",
+ "pass on lo",
+ "pass inet proto sctp to 192.0.2.0/24"])
+
+ # Set up a connection, which will try to create states for all
addresses
+ # we have assigned
+ client = SCTPClient("192.0.2.3", 1234)
+ client.send(b"hello", 0)
+ rcvd = self.wait_object(srv_vnet.pipe)
+ print(rcvd)
+ assert rcvd['ppid'] == 0
+ assert rcvd['data'] == "hello"
+
+ # But the number should be limited to 9 (original + 8 extra)
+ states = ToolsHelper.get_output("/sbin/pfctl -ss | grep 192.0.2.2")
+ print(states)
+ assert(states.count('\n') <= 9)
+
@pytest.mark.require_user("root")
def test_disallow_related(self):
srv_vnet = self.vnet_map["vnet2"]
