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Check for tcp th_off < 5 (NSE)

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dmiller 2026-06-26 22:06:06 +00:00
parent b5c54d9687
commit aed330325b
1 changed files with 8 additions and 0 deletions
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8
nselib/packet.lua
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@ -534,6 +534,10 @@ function Packet:ip_parse(force_continue)
stdnse.debug2("Packet.ip_parse: Not IPv4")
return false
end
if self.ip_hl < 5 then
stdnse.debug2("Packet.ip_parse: Header length bad")
return false
end
self.ip = true
self.ip_tos = self:u8(self.ip_offset + 1)
self.ip_len = self:u16(self.ip_offset + 2)
@ -796,6 +800,10 @@ function Packet:tcp_parse(force_continue)
self.tcp_seq = self:u32(self.tcp_offset + 4)
self.tcp_ack = self:u32(self.tcp_offset + 8)
self.tcp_hl = (self:u8(self.tcp_offset+12) & 0xF0) >> 4 -- header_length or data_offset
if self.tcp_hl < 5 then
stdnse.debug2("Packet.tcp_parse: Header length bad")
return false
end
self.tcp_x2 = (self:u8(self.tcp_offset+12) & 0x0F)
self.tcp_flags = self:u8(self.tcp_offset + 13)
self.tcp_th_fin = (self.tcp_flags & 0x01)~=0 -- true/false