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- --[[
- Copyright (c) 2022, Vsevolod Stakhov <vsevolod@rspamd.com>
-
- Licensed under the Apache License, Version 2.0 (the "License");
- you may not use this file except in compliance with the License.
- You may obtain a copy of the License at
-
- http://www.apache.org/licenses/LICENSE-2.0
-
- Unless required by applicable law or agreed to in writing, software
- distributed under the License is distributed on an "AS IS" BASIS,
- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- See the License for the specific language governing permissions and
- limitations under the License.
- ]]--
-
- --[[[
- -- @module clamav
- -- This module contains clamav access functions
- --]]
-
- local lua_util = require "lua_util"
- local tcp = require "rspamd_tcp"
- local upstream_list = require "rspamd_upstream_list"
- local rspamd_util = require "rspamd_util"
- local rspamd_logger = require "rspamd_logger"
- local common = require "lua_scanners/common"
-
- local N = "clamav"
-
- local default_message = '${SCANNER}: virus found: "${VIRUS}"'
-
- local function clamav_config(opts)
- local clamav_conf = {
- name = N,
- scan_mime_parts = true,
- scan_text_mime = false,
- scan_image_mime = false,
- default_port = 3310,
- log_clean = false,
- timeout = 5.0, -- FIXME: this will break task_timeout!
- detection_category = "virus",
- retransmits = 2,
- cache_expire = 3600, -- expire redis in one hour
- message = default_message,
- }
-
- clamav_conf = lua_util.override_defaults(clamav_conf, opts)
-
- if not clamav_conf.prefix then
- clamav_conf.prefix = 'rs_' .. clamav_conf.name .. '_'
- end
-
- if not clamav_conf.log_prefix then
- if clamav_conf.name:lower() == clamav_conf.type:lower() then
- clamav_conf.log_prefix = clamav_conf.name
- else
- clamav_conf.log_prefix = clamav_conf.name .. ' (' .. clamav_conf.type .. ')'
- end
- end
-
- if not clamav_conf['servers'] then
- rspamd_logger.errx(rspamd_config, 'no servers defined')
-
- return nil
- end
-
- clamav_conf['upstreams'] = upstream_list.create(rspamd_config,
- clamav_conf['servers'],
- clamav_conf.default_port)
-
- if clamav_conf['upstreams'] then
- lua_util.add_debug_alias('antivirus', clamav_conf.name)
- return clamav_conf
- end
-
- rspamd_logger.errx(rspamd_config, 'cannot parse servers %s',
- clamav_conf['servers'])
- return nil
- end
-
- local function clamav_check(task, content, digest, rule, maybe_part)
- local function clamav_check_uncached ()
- local upstream = rule.upstreams:get_upstream_round_robin()
- local addr = upstream:get_addr()
- local retransmits = rule.retransmits
- local header = rspamd_util.pack("c9 c1 >I4", "zINSTREAM", "\0",
- #content)
- local footer = rspamd_util.pack(">I4", 0)
-
- local function clamav_callback(err, data)
- if err then
-
- -- retry with another upstream until retransmits exceeds
- if retransmits > 0 then
-
- retransmits = retransmits - 1
-
- -- Select a different upstream!
- upstream = rule.upstreams:get_upstream_round_robin()
- addr = upstream:get_addr()
-
- lua_util.debugm(rule.name, task, '%s: error: %s; retry IP: %s; retries left: %s',
- rule.log_prefix, err, addr, retransmits)
-
- tcp.request({
- task = task,
- host = addr:to_string(),
- port = addr:get_port(),
- upstream = upstream,
- timeout = rule['timeout'],
- callback = clamav_callback,
- data = { header, content, footer },
- stop_pattern = '\0'
- })
- else
- rspamd_logger.errx(task, '%s: failed to scan, maximum retransmits exceed', rule.log_prefix)
- common.yield_result(task, rule,
- 'failed to scan and retransmits exceed', 0.0, 'fail',
- maybe_part)
- end
-
- else
- data = tostring(data)
- local cached
- lua_util.debugm(rule.name, task, '%s: got reply: %s',
- rule.log_prefix, data)
- if data == 'stream: OK' then
- cached = 'OK'
- if rule['log_clean'] then
- rspamd_logger.infox(task, '%s: message or mime_part is clean',
- rule.log_prefix)
- else
- lua_util.debugm(rule.name, task, '%s: message or mime_part is clean', rule.log_prefix)
- end
- else
- local vname = string.match(data, 'stream: (.+) FOUND')
- if string.find(vname, '^Heuristics%.Encrypted') then
- rspamd_logger.errx(task, '%s: File is encrypted', rule.log_prefix)
- common.yield_result(task, rule, 'File is encrypted: ' .. vname,
- 0.0, 'encrypted', maybe_part)
- cached = 'ENCRYPTED'
- elseif string.find(vname, '^Heuristics%.OLE2%.ContainsMacros') then
- rspamd_logger.errx(task, '%s: ClamAV Found an OLE2 Office Macro', rule.log_prefix)
- common.yield_result(task, rule, vname, 0.0, 'macro', maybe_part)
- cached = 'MACRO'
- elseif string.find(vname, '^Heuristics%.Limits%.Exceeded') then
- rspamd_logger.errx(task, '%s: ClamAV Limits Exceeded', rule.log_prefix)
- common.yield_result(task, rule, 'Limits Exceeded: ' .. vname, 0.0,
- 'fail', maybe_part)
- elseif vname then
- common.yield_result(task, rule, vname, 1.0, nil, maybe_part)
- cached = vname
- else
- rspamd_logger.errx(task, '%s: unhandled response: %s', rule.log_prefix, data)
- common.yield_result(task, rule, 'unhandled response:' .. vname, 0.0,
- 'fail', maybe_part)
- end
- end
- if cached then
- common.save_cache(task, digest, rule, cached, 1.0, maybe_part)
- end
- end
- end
-
- tcp.request({
- task = task,
- host = addr:to_string(),
- port = addr:get_port(),
- timeout = rule['timeout'],
- callback = clamav_callback,
- upstream = upstream,
- data = { header, content, footer },
- stop_pattern = '\0'
- })
- end
-
- if common.condition_check_and_continue(task, content, rule, digest,
- clamav_check_uncached, maybe_part) then
- return
- else
- clamav_check_uncached()
- end
-
- end
-
- return {
- type = 'antivirus',
- description = 'clamav antivirus',
- configure = clamav_config,
- check = clamav_check,
- name = N
- }
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