Merge pull request #282 from alegacy/master

vxlan: fixed incorrect field layout specification
secdev · Aug 31, 2016 · 8a81780 · 8a81780
2 parents 6280482 + 9e276ec
commit 8a81780
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Showing 2 changed files with 34 additions and 12 deletions.
diff --git a/scapy/layers/vxlan.py b/scapy/layers/vxlan.py
@@ -12,7 +12,7 @@
 from scapy.layers.inet import IP, UDP
 from scapy.layers.inet6 import IPv6
 from scapy.fields import FlagsField, XByteField, ThreeBytesField, \
-        ConditionalField, ShortField, ByteEnumField, X3BytesField
+    ConditionalField, ShortField, ByteEnumField, X3BytesField
 
 _GP_FLAGS = ["R", "R", "R", "A", "R", "R", "D", "R"]
 
@@ -24,15 +24,22 @@ class VXLAN(Packet):
         FlagsField("flags", 0x8, 8,
                    ['OAM', 'R', 'NextProtocol', 'Instance',
                     'V1', 'V2', 'R', 'G']),
-        ByteEnumField('NextProtocol', 0,
-                      {0: 'NotDefined',
-                       1: 'IPv4',
-                       2: 'IPv6',
-                       3: 'Ethernet',
-                       4: 'NSH'}),
+        ConditionalField(
+            ShortField("reserved0", 0),
+            lambda pkt: pkt.flags & 0x04,
+        ),
+        ConditionalField(
+            ByteEnumField('NextProtocol', 0,
+                          {0: 'NotDefined',
+                           1: 'IPv4',
+                           2: 'IPv6',
+                           3: 'Ethernet',
+                           4: 'NSH'}),
+            lambda pkt: pkt.flags & 0x04,
+        ),
         ConditionalField(
             ThreeBytesField("reserved1", 0x000000),
-            lambda pkt: not pkt.flags & 0x80,
+            lambda pkt: (not pkt.flags & 0x80) and (not pkt.flags & 0x04),
         ),
         ConditionalField(
             FlagsField("gpflags", 0x0, 8, _GP_FLAGS),
@@ -58,9 +65,11 @@ def mysummary(self):
             return self.sprintf("VXLAN (vni=%VXLAN.vni%)")
 
 bind_layers(UDP, VXLAN, dport=4789)  # RFC standard port
-bind_layers(UDP, VXLAN, dport=6633)  # New IANA assigned port when used with NSH
+bind_layers(UDP, VXLAN, dport=6633)  # New IANA assigned port for use with NSH
 bind_layers(UDP, VXLAN, dport=8472)  # Linux implementation port
-bind_layers(VXLAN, Ether, {'flags': 0x8}, NextProtocol=0)
+bind_layers(VXLAN, Ether, {'flags': 0x8})
+bind_layers(VXLAN, Ether, {'flags': 0x88})
+bind_layers(VXLAN, Ether, {'flags': 0xC, 'NextProtocol': 0}, NextProtocol=0)
 bind_layers(VXLAN, IP, {'flags': 0xC, 'NextProtocol': 1}, NextProtocol=1)
 bind_layers(VXLAN, IPv6, {'flags': 0xC, 'NextProtocol': 2}, NextProtocol=2)
 bind_layers(VXLAN, Ether, {'flags': 0xC, 'NextProtocol': 3}, NextProtocol=3)
diff --git a/test/regression.uts b/test/regression.uts
@@ -6123,17 +6123,28 @@ assert(p.data[0].ifname.startswith("lo"))
 + VXLAN layer
 
 = Build a VXLAN packet with VNI of 42
-str(UDP(sport=1024, dport=4789, len=None, chksum=None)/VXLAN(flags=0x08, vni=42)) == '\x04\x00\x12\xb5\x00\x11\x00\x00\x08\x00\x00\x00\x00\x00\x00\x2a\x00'
+str(UDP(sport=1024, dport=4789, len=None, chksum=None)/VXLAN(flags=0x08, vni=42)) == '\x04\x00\x12\xb5\x00\x10\x00\x00\x08\x00\x00\x00\x00\x00\x2a\x00'
 
 = Verify VXLAN Ethernet Binding
-str(VXLAN(vni=23)/Ether(dst="11:11:11:11:11:11", src="11:11:11:11:11:11", type=0x800)) == '\x0c\x03\x00\x00\x00\x00\x00\x17\x00\x11\x11\x11\x11\x11\x11\x11\x11\x11\x11\x11\x11\x08\x00'
+str(VXLAN(vni=23)/Ether(dst="11:11:11:11:11:11", src="11:11:11:11:11:11", type=0x800)) == '\x0c\x00\x00\x03\x00\x00\x17\x00\x11\x11\x11\x11\x11\x11\x11\x11\x11\x11\x11\x11\x08\x00'
 
 = Verify UDP dport overloading
 p = Ether(dst="11:11:11:11:11:11", src="22:22:22:22:22:22")
 p /= IP(src="1.1.1.1", dst="2.2.2.2") / UDP(sport=1111)
 p /= VXLAN(flags=0x8, vni=42) / Ether() / IP()
 p = Ether(str(p))
 assert(p[UDP].dport == 8472)
+assert(p[Ether:2].type == 0x800)
+
+= Build a VXLAN packet with next protocol field
+p = Ether(dst="11:11:11:11:11:11", src="22:22:22:22:22:22")
+p /= IP(src="1.1.1.1", dst="2.2.2.2") / UDP(sport=1111)
+p /= VXLAN(flags=0xC, vni=42, NextProtocol=3) / Ether() / IP()
+p = Ether(str(p))
+assert(p[UDP].dport == 8472)
+assert(p[VXLAN].reserved0 == 0x0)
+assert(p[VXLAN].NextProtocol == 3)
+assert(p[Ether:2].type == 0x800)
 
 = Build a VXLAN packet with no group policy ID
 p = Ether(dst="11:11:11:11:11:11", src="22:22:22:22:22:22")
@@ -6142,6 +6153,7 @@ p /= VXLAN(flags=0x8, vni=42) / Ether() / IP()
 p = Ether(str(p))
 assert(p[VXLAN].reserved1 == 0x0)
 assert(p[VXLAN].gpid is None)
+assert(p[Ether:2].type == 0x800)
 
 = Build a VXLAN packet with group policy ID = 42
 p = Ether(dst="11:11:11:11:11:11", src="22:22:22:22:22:22")
@@ -6150,3 +6162,4 @@ p /= VXLAN(flags=0x88, gpid=42, vni=42) / Ether() / IP()
 p = Ether(str(p))
 assert(p[VXLAN].gpid == 42)
 assert(p[VXLAN].reserved1 is None)
+assert(p[Ether:2].type == 0x800)