Date: Tue, 25 Nov 2025 15:04:43 +0000 From: Kristof Provost <kp@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: bc3b72ff4895 - main - pf: relax sctp v_tag verification Message-ID: <6925c58b.348ed.7b222851@gitrepo.freebsd.org>
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The branch main has been updated by kp: URL: https://cgit.FreeBSD.org/src/commit/?id=bc3b72ff48953551e0e8bd6e5a2c718ecd973285 commit bc3b72ff48953551e0e8bd6e5a2c718ecd973285 Author: Kristof Provost <kp@FreeBSD.org> AuthorDate: 2025-11-25 09:59:02 +0000 Commit: Kristof Provost <kp@FreeBSD.org> CommitDate: 2025-11-25 14:59:55 +0000 pf: relax sctp v_tag verification pf was too strict when validating SCTP tags. When a server receives a retransmitted INIT it will reply with a random initiate tag every time. However, pf saves the first initiate tag and expects every subsequent INIT_ACK retransmission to have the same tag. This is not the case, leading to endless INIT/INIT_ACK cycles. Allow the tag to be updated as long as we've not gone past COOKIE_WAIT. Add a test case to verify this. MFC after: 2 weeks See also: https://redmine.pfsense.org/issues/16516 Sponsored by: Rubicon Communications, LLC ("Netgate") --- sys/netpfil/pf/pf.c | 6 +++- tests/sys/netpfil/pf/sctp.py | 67 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 72 insertions(+), 1 deletion(-) diff --git a/sys/netpfil/pf/pf.c b/sys/netpfil/pf/pf.c index 5e919e35b07b..74d2182fe77b 100644 --- a/sys/netpfil/pf/pf.c +++ b/sys/netpfil/pf/pf.c @@ -7396,7 +7396,11 @@ pf_sctp_track(struct pf_kstate *state, struct pf_pdesc *pd, } if (src->scrub != NULL) { - if (src->scrub->pfss_v_tag == 0) + /* + * Allow tags to be updated, in case of retransmission of + * INIT/INIT_ACK chunks. + **/ + if (src->state <= SCTP_COOKIE_WAIT) src->scrub->pfss_v_tag = pd->hdr.sctp.v_tag; else if (src->scrub->pfss_v_tag != pd->hdr.sctp.v_tag) return (PF_DROP); diff --git a/tests/sys/netpfil/pf/sctp.py b/tests/sys/netpfil/pf/sctp.py index f492f26b63a1..9f1d7dea4ef6 100644 --- a/tests/sys/netpfil/pf/sctp.py +++ b/tests/sys/netpfil/pf/sctp.py @@ -551,6 +551,73 @@ class TestSCTP(VnetTestTemplate): assert re.search(r"epair.*sctp 192.0.2.1:.*192.0.2.3:1234", states) assert re.search(r"epair.*sctp 192.0.2.1:.*192.0.2.2:1234", states) +class TestSCTP_SRV(VnetTestTemplate): + REQUIRED_MODULES = ["sctp", "pf"] + TOPOLOGY = { + "vnet1": {"ifaces": ["if1"]}, + "vnet2": {"ifaces": ["if1"]}, + "if1": {"prefixes4": [("192.0.2.1/24", "192.0.2.2/24")]}, + } + + def vnet2_handler(self, vnet): + ToolsHelper.print_output("/sbin/pfctl -e") + ToolsHelper.pf_rules([ + "set state-policy if-bound", + "pass inet proto sctp", + "pass on lo"]) + + # Start an SCTP server process, pipe the ppid + data back to the other vnet? + srv = SCTPServer(socket.AF_INET, port=1234) + while True: + srv.accept(vnet) + + @pytest.mark.require_user("root") + @pytest.mark.require_progs(["scapy"]) + def test_initiate_tag_check(self): + # Ensure we don't send ABORTs in response to the other end's INIT_ACK + # That'd interfere with our test. + ToolsHelper.print_output("/sbin/sysctl net.inet.sctp.blackhole=2") + + import scapy.all as sp + + packet = sp.IP(src="192.0.2.1", dst="192.0.2.2") \ + / sp.SCTP(sport=1234, dport=1234) \ + / sp.SCTPChunkInit(init_tag=1, n_in_streams=1, n_out_streams=1, a_rwnd=1500) + packet.show() + + r = sp.sr1(packet, timeout=3) + assert r + r.show() + assert r.getlayer(sp.SCTP) + assert r.getlayer(sp.SCTPChunkInitAck) + assert r.getlayer(sp.SCTP).tag == 1 + + # Send another INIT with the same initiate tag, expect another init ack + packet = sp.IP(src="192.0.2.1", dst="192.0.2.2") \ + / sp.SCTP(sport=1234, dport=1234) \ + / sp.SCTPChunkInit(init_tag=1, n_in_streams=1, n_out_streams=1, a_rwnd=1500) + packet.show() + + r = sp.sr1(packet, timeout=3) + assert r + r.show() + assert r.getlayer(sp.SCTP) + assert r.getlayer(sp.SCTPChunkInitAck) + assert r.getlayer(sp.SCTP).tag == 1 + + # Send an INIT with a different initiate tag, expect another init ack + packet = sp.IP(src="192.0.2.1", dst="192.0.2.2") \ + / sp.SCTP(sport=1234, dport=1234) \ + / sp.SCTPChunkInit(init_tag=42, n_in_streams=1, n_out_streams=1, a_rwnd=1500) + packet.show() + + r = sp.sr1(packet, timeout=3) + assert r + r.show() + assert r.getlayer(sp.SCTP) + assert r.getlayer(sp.SCTPChunkInitAck) + assert r.getlayer(sp.SCTP).tag == 42 + class TestSCTPv6(VnetTestTemplate): REQUIRED_MODULES = ["sctp", "pf"] TOPOLOGY = {help
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