git: 6f9ddb329b07 - main - pf: improve SCTP validation

The branch main has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=6f9ddb329b07099e392c78b6e4fef1c6252de0dc

commit 6f9ddb329b07099e392c78b6e4fef1c6252de0dc
Author:     Kristof Provost <kp@FreeBSD.org>
AuthorDate: 2026-04-26 09:34:55 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2026-04-29 14:39:28 +0000

    pf: improve SCTP validation
    
    As per RFC5061 "4.2.  New Parameter Types" the add/delete IP address
    parameters (0xc001, 0xc002) may not be present in an INIT or INIT-ACK
    chunk. They are only allowed to be present in an ASCONF chunk.
    
    This also prevents unbounded recursion while parsing an SCTP packet.
    
    Approved by:    so
    Security:       FreeBSD-SA-26:14.pf
    Security:       CVE-2026-7164
    PR:             294799
    Reported by:    Igor Gabriel Sousa e Souza
    Sponsored by:   Orange Business Services
---
 sys/netpfil/pf/pf.c          | 16 +++++++++++-----
 tests/sys/netpfil/pf/sctp.py | 23 +++++++++++++++++++++++
 2 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/sys/netpfil/pf/pf.c b/sys/netpfil/pf/pf.c
index 53f74271e268..27d03b688937 100644
--- a/sys/netpfil/pf/pf.c
+++ b/sys/netpfil/pf/pf.c
@@ -8353,7 +8353,7 @@ again:
 }
 
 static int
-pf_multihome_scan(int start, int len, struct pf_pdesc *pd, int op)
+pf_multihome_scan(int start, int len, struct pf_pdesc *pd, int op, bool asconf)
 {
 	int			 off = 0;
 	struct pf_sctp_multihome_job	*job;
@@ -8458,6 +8458,9 @@ pf_multihome_scan(int start, int len, struct pf_pdesc *pd, int op)
 			int ret;
 			struct sctp_asconf_paramhdr ah;
 
+			if (asconf)
+				return (PF_DROP);
+
 			if (!pf_pull_hdr(pd->m, start + off, &ah, sizeof(ah),
 			    NULL, pd->af))
 				return (PF_DROP);
@@ -8467,7 +8470,7 @@ pf_multihome_scan(int start, int len, struct pf_pdesc *pd, int op)
 
 			ret = pf_multihome_scan(start + off + sizeof(ah),
 			    ntohs(ah.ph.param_length) - sizeof(ah), pd,
-			    SCTP_ADD_IP_ADDRESS);
+			    SCTP_ADD_IP_ADDRESS, true);
 			if (ret != PF_PASS)
 				return (ret);
 			break;
@@ -8476,6 +8479,9 @@ pf_multihome_scan(int start, int len, struct pf_pdesc *pd, int op)
 			int ret;
 			struct sctp_asconf_paramhdr ah;
 
+			if (asconf)
+				return (PF_DROP);
+
 			if (!pf_pull_hdr(pd->m, start + off, &ah, sizeof(ah),
 			    NULL, pd->af))
 				return (PF_DROP);
@@ -8485,7 +8491,7 @@ pf_multihome_scan(int start, int len, struct pf_pdesc *pd, int op)
 
 			ret = pf_multihome_scan(start + off + sizeof(ah),
 			    ntohs(ah.ph.param_length) - sizeof(ah), pd,
-			    SCTP_DEL_IP_ADDRESS);
+			    SCTP_DEL_IP_ADDRESS, true);
 			if (ret != PF_PASS)
 				return (ret);
 			break;
@@ -8506,7 +8512,7 @@ pf_multihome_scan_init(int start, int len, struct pf_pdesc *pd)
 	start += sizeof(struct sctp_init_chunk);
 	len -= sizeof(struct sctp_init_chunk);
 
-	return (pf_multihome_scan(start, len, pd, SCTP_ADD_IP_ADDRESS));
+	return (pf_multihome_scan(start, len, pd, SCTP_ADD_IP_ADDRESS, false));
 }
 
 int
@@ -8515,7 +8521,7 @@ pf_multihome_scan_asconf(int start, int len, struct pf_pdesc *pd)
 	start += sizeof(struct sctp_asconf_chunk);
 	len -= sizeof(struct sctp_asconf_chunk);
 
-	return (pf_multihome_scan(start, len, pd, SCTP_ADD_IP_ADDRESS));
+	return (pf_multihome_scan(start, len, pd, SCTP_ADD_IP_ADDRESS, false));
 }
 
 int
diff --git a/tests/sys/netpfil/pf/sctp.py b/tests/sys/netpfil/pf/sctp.py
index 9f1d7dea4ef6..722f7777a305 100644
--- a/tests/sys/netpfil/pf/sctp.py
+++ b/tests/sys/netpfil/pf/sctp.py
@@ -618,6 +618,29 @@ class TestSCTP_SRV(VnetTestTemplate):
         assert r.getlayer(sp.SCTPChunkInitAck)
         assert r.getlayer(sp.SCTP).tag == 42
 
+    @pytest.mark.require_user("root")
+    @pytest.mark.require_progs(["scapy"])
+    def test_too_many_add_ip(self):
+        import scapy.all as sp
+        DEPTH=90
+        params=[]
+        for i in range(0, DEPTH):
+            ch = sp.SCTPChunkParamAddIPAddr(len=(DEPTH - i) * 8)
+            params.append(ch)
+        packet = sp.IP(src="192.0.2.1", dst="192.0.2.2") \
+            / sp.SCTP(sport=4321, dport=1234) \
+            / sp.SCTPChunkInit(init_tag=1, n_in_streams=1, n_out_streams=1, a_rwnd=1500,
+                params=params)
+        packet.show()
+        sp.hexdump(packet)
+        print("len %d" % len(packet))
+
+        r = sp.sr1(packet, timeout=3)
+        # We should not get a reply to this
+        if r:
+            r.show()
+        assert not r
+
 class TestSCTPv6(VnetTestTemplate):
     REQUIRED_MODULES = ["sctp", "pf"]
     TOPOLOGY = {