Adding upstream version 7.94+git20230807.3be01efb1+dfsg.upstream/7.94+git20230807.3be01efb1+dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 598 insertions, 0 deletions

diff --git a/nselib/snmp.lua b/nselib/snmp.lua
new file mode 100644
index 0000000..b732160
--- /dev/null
+++ b/nselib/snmp.lua
@@ -0,0 +1,598 @@
+---
+-- SNMP library.
+--
+-- @args snmp.version The SNMP protocol version. Use <code>"v1"</code> or <code>0</code> for SNMPv1 (default) and <code>"v2c"</code> or <code>1</code> for SNMPv2c.
+--
+-- @author Patrik Karlsson <patrik@cqure.net>
+-- @author Gioacchino Mazzurco <gmazzurco89@gmail.com>
+-- @copyright Same as Nmap--See https://nmap.org/book/man-legal.html
+
+-- 2015-06-11 Gioacchino Mazzurco - Use creds library to handle SNMP community
+
+local asn1 = require "asn1"
+local creds = require "creds"
+local math = require "math"
+local nmap = require "nmap"
+local stdnse = require "stdnse"
+local string = require "string"
+local table = require "table"
+_ENV = stdnse.module("snmp", stdnse.seeall)
+
+
+-- SNMP ASN.1 Encoders
+local tagEncoder = {}
+
+-- Override the boolean encoder
+tagEncoder['boolean'] = function(self, val)
+  return '\x05\x00'
+end
+
+-- Complex tag encoders
+tagEncoder['table'] = function(self, val)
+  if val._snmp == '\x06' then -- OID
+    local oidStr = string.char(val[1]*40 + val[2])
+    for i = 3, #val do
+      oidStr = oidStr .. self.encode_oid_component(val[i])
+    end
+    return val._snmp .. self.encodeLength(#oidStr) .. oidStr
+
+  elseif (val._snmp == '\x40') then -- ipAddress
+    return string.pack('Bs1', 0x40, string.pack('BBBB', table.unpack(val)))
+
+    -- counter or gauge or timeticks or opaque
+  elseif (val._snmp == '\x41' or val._snmp == '\x42' or val._snmp == '\x43' or val._snmp == '\x44') then
+    local val = self:encodeInt(val[1])
+    return val._snmp .. self.encodeLength(#val) .. val
+  end
+
+  local encVal = ""
+  for _, v in ipairs(val) do
+    encVal = encVal .. self:encode(v) -- todo: buffer?
+  end
+
+  local tableType = val._snmp or "\x30"
+  return tableType .. self.encodeLength(#encVal) .. encVal
+end
+
+---
+-- Encodes a given value according to ASN.1 basic encoding rules for SNMP
+-- packet creation.
+-- @param val Value to be encoded.
+-- @return Encoded value.
+function encode(val)
+  local vtype = type(val)
+  local encoder = asn1.ASN1Encoder:new()
+  encoder:registerTagEncoders( tagEncoder )
+
+
+  local encVal = encoder:encode(val)
+
+  if encVal then
+    return encVal
+  end
+
+  return ''
+end
+
+-- SNMP ASN.1 Decoders
+local tagDecoder = {}
+
+-- Application specific tags
+--
+-- IP Address
+
+-- Response-PDU
+-- TOOD: Figure out how to remove these dependencies
+tagDecoder["\xa2"] = function( self, encStr, elen, pos )
+   local seq = {}
+
+   seq, pos = self:decodeSeq(encStr, elen, pos)
+   seq._snmp = "\xa2"
+   return seq, pos
+end
+
+tagDecoder["\x40"] = function( self, encStr, elen, pos )
+  local ip = {}
+  -- TODO: possibly convert to ipOps.str_to_ip() if octets are not used separately elsewhere.
+  ip[1], ip[2], ip[3], ip[4], pos = string.unpack("BBBB", encStr, pos)
+  ip._snmp = '\x40'
+  return ip, pos
+end
+
+---
+-- Decodes an SNMP packet or a part of it according to ASN.1 basic encoding
+-- rules.
+-- @param encStr Encoded string.
+-- @param pos Current position in the string.
+-- @return The decoded value(s).
+-- @return The position after decoding
+function decode(encStr, pos)
+  local decoder = asn1.ASN1Decoder:new()
+
+  if ( #tagDecoder == 0 ) then
+    decoder:registerBaseDecoders()
+    -- Application specific tags
+    -- tagDecoder["40"] = decoder.decoder["06"]  -- IP Address; same as OID
+    tagDecoder["\x41"] = decoder.decoder["\x02"]  -- Counter; same as Integer
+    tagDecoder["\x42"] = decoder.decoder["\x02"]  -- Gauge
+    tagDecoder["\x43"] = decoder.decoder["\x02"]  -- TimeTicks
+    tagDecoder["\x44"] = decoder.decoder["\x04"]  -- Opaque; same as Octet String
+    tagDecoder["\x45"] = decoder.decoder["\x06"]  -- NsapAddress
+    tagDecoder["\x46"] = decoder.decoder["\x02"]  -- Counter64
+    tagDecoder["\x47"] = decoder.decoder["\x02"]  -- UInteger32
+
+    -- Context specific tags
+    tagDecoder["\xa0"] = decoder.decoder["\x30"]  -- GetRequest-PDU
+    tagDecoder["\xa1"] = decoder.decoder["\x30"]  -- GetNextRequest-PDU
+    --tagDecoder["\xa2"] = decoder.decoder["\x30"]  -- Response-PDU
+    tagDecoder["\xa3"] = decoder.decoder["\x30"]  -- SetRequest-PDU
+    tagDecoder["\xa4"] = decoder.decoder["\x30"]  -- Trap-PDU
+    tagDecoder["\xa5"] = decoder.decoder["\x30"]  -- GetBulkRequest-PDU
+    tagDecoder["\xa6"] = decoder.decoder["\x30"]  -- InformRequest-PDU (not implemented here yet)
+    tagDecoder["\xa7"] = decoder.decoder["\x30"]  -- SNMPv2-Trap-PDU (not implemented here yet)
+    tagDecoder["\xa8"] = decoder.decoder["\x30"]  -- Report-PDU (not implemented here yet)
+  end
+
+
+  decoder:registerTagDecoders( tagDecoder )
+
+  return decoder:decode( encStr, pos )
+end
+
+local version_to_num = {v1=0, v2c=1}
+local num_to_version = {[0]="v1", [1]="v2c"}
+
+--- Returns the numerical value of a given SNMP protocol version
+--
+-- Numerical input is simply passed through, assuming it is valid.
+-- String input is translated to its corresponding numerical value.
+-- @param version of the SNMP protocol. See script argument <code>snmp.version</code> for valid codes
+-- @param default numerical version of the SNMP protocol if the <code>version</code> parameter is <code>nil</code> or its value is invalid.
+-- @return 0 or 1, depending on which protocol version was specified.
+local function getVersion (version, default)
+  if version then
+    version = version_to_num[version] or tonumber(version)
+    if num_to_version[version] then
+      return version
+    end
+    stdnse.debug1("Unrecognized SNMP version; proceeding with SNMP%s", num_to_version[default])
+  end
+  return default
+end
+
+-- the library functions will use this version of SNMP by default
+local default_version = getVersion(stdnse.get_script_args("snmp.version"), 0)
+
+---
+-- Create an SNMP packet.
+-- @param PDU SNMP Protocol Data Unit to be encapsulated in the packet.
+-- @param version SNMP version; defaults to script argument <code>snmp.version</code>
+-- @param commStr community string.
+function buildPacket(PDU, version, commStr)
+  local packet = {}
+  packet[1] = getVersion(version, default_version)
+  packet[2] = commStr
+  packet[3] = PDU
+  return packet
+end
+
+--- SNMP options table
+-- @class table
+-- @name snmp.options
+-- @field reqId Request ID.
+-- @field err Error.
+-- @field errIdx Error index.
+
+---
+-- Create an SNMP Get Request PDU.
+-- @param options SNMP options table
+-- @see snmp.options
+-- @param ... Object identifiers to be queried.
+-- @return Table representing PDU.
+function buildGetRequest(options, ...)
+  if not options then options = {} end
+
+  if not options.reqId then options.reqId = math.fmod(nmap.clock_ms(), 65000) end
+  if not options.err then options.err = 0 end
+  if not options.errIdx then options.errIdx = 0 end
+
+  local req = {}
+  req._snmp = '\xa0'
+  req[1] = options.reqId
+  req[2] = options.err
+  req[3] = options.errIdx
+
+  local payload = {}
+  for i=1, select('#', ...) do
+    payload[i] = {}
+    payload[i][1] = select(i, ...)
+    if type(payload[i][1]) == "string" then
+      payload[i][1] = str2oid(payload[i][1])
+    end
+    payload[i][2] = false
+  end
+  req[4] = payload
+  return req
+end
+
+
+---
+-- Create an SNMP Get Next Request PDU.
+-- @param options SNMP options table
+-- @see snmp.options
+-- @param ... Object identifiers to be queried.
+-- @return Table representing PDU.
+function buildGetNextRequest(options, ...)
+  options = options or {}
+  options.reqId = options.reqId or math.fmod(nmap.clock_ms(), 65000)
+  options.err = options.err or 0
+  options.errIdx = options.errIdx or 0
+
+  local req = {}
+  req._snmp = '\xa1'
+  req[1] = options.reqId
+  req[2] = options.err
+  req[3] = options.errIdx
+
+  local payload = {}
+  for i=1, select('#', ...) do
+    payload[i] = {}
+    payload[i][1] = select(i, ...)
+    if type(payload[i][1]) == "string" then
+      payload[i][1] = str2oid(payload[i][1])
+    end
+    payload[i][2] = false
+  end
+  req[4] = payload
+  return req
+end
+
+---
+-- Create an SNMP Set Request PDU.
+--
+-- Takes one OID/value pair or an already prepared table.
+-- @param options SNMP options table
+-- @see snmp.options
+-- @param oid Object identifiers of object to be set.
+-- @param value To which value object should be set. If given a table, use the
+-- table instead of OID/value pair.
+-- @return Table representing PDU.
+function buildSetRequest(options, oid, value)
+  if not options then options = {} end
+
+  if not options.reqId then options.reqId = math.fmod(nmap.clock_ms(), 65000) end
+  if not options.err then options.err = 0 end
+  if not options.errIdx then options.errIdx = 0 end
+
+  local req = {}
+  req._snmp = '\xa3'
+  req[1] = options.reqId
+  req[2] = options.err
+  req[3] = options.errIdx
+
+  if (type(value) == "table") then
+    req[4] = value
+  else
+    local payload = {}
+    if (type(oid) == "string") then
+      payload[1] = str2oid(oid)
+    else
+      payload[1] = oid
+    end
+    payload[2] = value
+    req[4] = {}
+    req[4][1] = payload
+  end
+  return req
+end
+
+---
+-- Create an SNMP Trap PDU.
+-- @return Table representing PDU
+function buildTrap(enterpriseOid, agentIp, genTrap, specTrap, timeStamp)
+  local req = {}
+  req._snmp = '\xa4'
+  if (type(enterpriseOid) == "string") then
+    req[1] = str2oid(enterpriseOid)
+  else
+    req[1] = enterpriseOid
+  end
+  req[2] = {}
+  req[2]._snmp = '\x40'
+  for n in string.gmatch(agentIp, "%d+") do
+    table.insert(req[2], tonumber(n))
+  end
+  req[3] = genTrap
+  req[4] = specTrap
+
+  req[5] = {}
+  req[5]._snmp = '\x43'
+  req[5][1] = timeStamp
+
+  req[6] = {}
+
+  return req
+end
+
+---
+-- Create an SNMP Get Response PDU.
+--
+-- Takes one OID/value pair or an already prepared table.
+-- @param options SNMP options table
+-- @see snmp.options
+-- @param oid Object identifiers of object to be sent back.
+-- @param value If given a table, use the table instead of OID/value pair.
+-- @return Table representing PDU.
+function buildGetResponse(options, oid, value)
+  if not options then options = {} end
+
+  -- if really a response, should use reqId of request!
+  if not options.reqId then options.reqId = math.fmod(nmap.clock_ms(), 65000) end
+  if not options.err then options.err = 0 end
+  if not options.errIdx then options.errIdx = 0 end
+
+  local resp = {}
+  resp._snmp = '\xa2'
+  resp[1] = options.reqId
+  resp[2] = options.err
+  resp[3] = options.errIdx
+
+  if (type(value) == "table") then
+    resp[4] = value
+  else
+
+    local payload = {}
+    if (type(oid) == "string") then
+      payload[1] = str2oid(oid)
+    else
+      payload[1] = oid
+    end
+    payload[2] = value
+    resp[4] = {}
+    resp[4][1] = payload
+  end
+  return resp
+end
+
+---
+-- Transforms a string into an object identifier table.
+-- @param oidStr Object identifier as string, for example
+-- <code>"1.3.6.1.2.1.1.1.0"</code>.
+-- @return Table representing OID.
+function str2oid(oidStr)
+  local oid = {}
+  for n in string.gmatch(oidStr, "%d+") do
+    table.insert(oid, tonumber(n))
+  end
+  oid._snmp = '\x06'
+  return oid
+end
+
+---
+-- Transforms a table representing an object identifier to a string.
+-- @param oid Object identifier table.
+-- @return OID string.
+function oid2str(oid)
+  if (type(oid) ~= "table") then return 'invalid oid' end
+  return table.concat(oid, '.')
+end
+
+---
+-- Transforms a table representing an IP to a string.
+-- @param ip IP table.
+-- @return IP string.
+function ip2str(ip)
+  if (type(ip) ~= "table") then return 'invalid ip' end
+  return table.concat(ip, '.')
+end
+
+
+---
+-- Transforms a string into an IP table.
+-- @param ipStr IP as string.
+-- @return Table representing IP.
+function str2ip(ipStr)
+  local ip = {}
+  for n in string.gmatch(ipStr, "%d+") do
+    table.insert(ip, tonumber(n))
+  end
+  ip._snmp = '\x40'
+  return ip
+end
+
+
+---
+-- Fetches values from a SNMP response.
+-- @param resp SNMP Response (will be decoded if necessary).
+-- @return Table with all decoded responses and their OIDs.
+function fetchResponseValues(resp)
+  if (type(resp) == "string") then
+    resp = decode(resp)
+  end
+
+  if (type(resp) ~= "table") then
+    return {}
+  end
+
+  local varBind
+  if (resp._snmp and resp._snmp == '\xa2') then
+    varBind = resp[4]
+  elseif (resp[3] and resp[3]._snmp and resp[3]._snmp == '\xa2') then
+    varBind = resp[3][4]
+  end
+
+  if (varBind and type(varBind) == "table") then
+    local result = {}
+    for k, v in ipairs(varBind) do
+      local val = v[2]
+      if (type(v[2]) == "table") then
+        if (v[2]._snmp == '\x40') then
+          val = v[2][1] .. '.' .. v[2][2] .. '.' .. v[2][3] .. '.' .. v[2][4]
+        elseif (v[2]._snmp == '\x41') then
+          val = v[2][1]
+        elseif (v[2]._snmp == '\x42') then
+          val = v[2][1]
+        elseif (v[2]._snmp == '\x43') then
+          val = v[2][1]
+        elseif (v[2]._snmp == '\x44') then
+          val = v[2][1]
+        end
+      end
+      table.insert(result, {val, oid2str(v[1]), v[1]})
+    end
+    return result
+  end
+  return {}
+end
+
+
+--- SNMP Helper class
+--
+-- Handles socket communication, parsing, and setting of community strings
+Helper = {
+
+  --- Creates a new Helper instance
+  --
+  -- @param host string containing the host name or ip
+  -- @param port table containing the port details to connect to
+  -- @param community string containing SNMP community
+  -- @param options A table with appropriate options:
+  --  * timeout - the timeout in milliseconds (Default: 5000)
+  --  * version - the SNMP version; defaults to script argument <code>snmp.version</code>.
+  -- @return o a new instance of Helper
+  new = function( self, host, port, community, options )
+    local o = {}
+    setmetatable(o, self)
+    self.__index = self
+    o.host = host
+    o.port = port
+
+    o.community = community or "public"
+    if community == nil then
+      local creds_store = creds.Credentials:new(creds.ALL_DATA, host, port)
+      for _,cs in ipairs({creds.State.PARAM, creds.State.VALID}) do
+        local account = creds_store:getCredentials(cs)()
+        if account then
+          if account.pass and account.pass ~= "<empty>" and account.pass ~= "" then
+            o.community = account.pass
+            break
+          elseif account.user then
+            o.community = account.user
+            break
+          end
+        end
+      end
+    end
+
+    o.options = options or {
+      timeout = 5000,
+      version = default_version
+    }
+
+    return o
+  end,
+
+  --- Connect to the server
+  -- For UDP ports, this doesn't send any packets, but it creates the
+  -- socket and locks in the timeout.
+  -- @return status true on success, false on failure
+  connect = function( self )
+    self.socket = nmap.new_socket()
+    self.socket:set_timeout(self.options.timeout)
+    local status, err = self.socket:connect(self.host, self.port)
+    if ( not(status) ) then return false, err end
+
+    return true
+  end,
+
+  --- Communications helper
+  -- Sends an SNMP message and receives a response.
+  -- @param message the result of one of the build*Request functions
+  -- @return status False if there was an error, true otherwise.
+  -- @return response The raw response read from the socket.
+  request = function (self, message)
+    local payload = encode( buildPacket(
+        message,
+        self.options.version,
+        self.community
+      ) )
+
+    local status, err = self.socket:send(payload)
+    if not status then
+      stdnse.debug2("snmp.Helper.request: Send to %s failed: %s", self.host.ip, err)
+      return false, err
+    end
+
+    return self.socket:receive_bytes(1)
+  end,
+
+  --- Sends an SNMP Get Next request
+  -- @param options SNMP options table
+  -- @see snmp.options
+  -- @param ... Object identifiers to be queried.
+  -- @return status False if error, true otherwise
+  -- @return Table with all decoded responses and their OIDs.
+  getnext = function (self, options, ...)
+    local status, response = self:request(buildGetNextRequest(options or {}, ...))
+    if not status then
+      return status, response
+    end
+    return status, fetchResponseValues(response)
+  end,
+
+  --- Sends an SNMP Get request
+  -- @param options SNMP options table
+  -- @see snmp.options
+  -- @param ... Object identifiers to be queried.
+  -- @return status False if error, true otherwise
+  -- @return Table with all decoded responses and their OIDs.
+  get = function (self, options, ...)
+    local status, response = self:request(buildGetRequest(options or {}, ...))
+    if not status then
+      return status, response
+    end
+    return status, fetchResponseValues(response)
+  end,
+
+  --- Sends an SNMP Set request
+  -- @param options SNMP options table
+  -- @see snmp.options
+  -- @param oid Object identifiers of object to be set.
+  -- @param value To which value object should be set. If given a table,
+  --              use the table instead of OID/value pair.
+  -- @return status False if error, true otherwise
+  -- @return Table with all decoded responses and their OIDs.
+  set = function (self, options, oid, setparam)
+    local status, response = self:request(buildSetRequest(options or {}, oid, setparam))
+    if not status then
+      return status, response
+    end
+    return status, fetchResponseValues(response)
+  end,
+
+  --- Walks the MIB Tree
+  --
+  -- @param base_oid string containing the base object ID to walk
+  -- @return status true on success, false on failure
+  -- @return table containing <code>oid</code> and <code>value</code>
+  walk = function (self, base_oid)
+
+    local snmp_table = { baseoid = base_oid }
+    local oid = base_oid
+    local options = {}
+
+    local status, snmpdata = self:getnext(options, oid)
+    while ( snmpdata and snmpdata[1] and snmpdata[1][1] and snmpdata[1][2] ) do
+      oid  = snmpdata[1][2]
+      if not oid:match(base_oid) or base_oid == oid then break end
+
+      table.insert(snmp_table, { oid = oid, value = snmpdata[1][1] })
+      local _ -- NSE don't want you to use global even if it is _
+      _, snmpdata = self:getnext(options, oid)
+    end
+
+    return status, snmp_table
+  end
+}
+
+return _ENV;