[Feature] Plugins: Add preliminary version of the external services plugin

diff --git a/src/plugins/lua/external_services.lua b/src/plugins/lua/external_services.lua
new file mode 100644 (file)
index 0000000..1b6c9b7
--- /dev/null
+++ b/src/plugins/lua/external_services.lua
@@ -0,0 +1,196 @@
+--[[
+Copyright (c) 2019, Vsevolod Stakhov <vsevolod@highsecure.ru>
+
+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.
+]] --
+
+local rspamd_logger = require "rspamd_logger"
+local rspamd_regexp = require "rspamd_regexp"
+local lua_util = require "lua_util"
+local lua_scanners = require("lua_scanners").filter('scanner')
+local redis_params
+
+local N = "external_services"
+
+if confighelp then
+  rspamd_config:add_example(nil, 'external_services',
+    "Check messages using external services (e.g. OEM AS engines, DCC, Pyzor etc)",
+    [[
+external_services {
+  # multiple scanners could be checked, for each we create a configuration block with an arbitrary name
+  dcc {
+    # If set force this action if any virus is found (default unset: no action is forced)
+    # action = "reject";
+    # If set, then rejection message is set to this value (mention single quotes)
+    # If `max_size` is set, messages > n bytes in size are not scanned
+    max_size = 20000000;
+    servers = "127.0.0.1:3310";
+    # if `patterns` is specified virus name will be matched against provided regexes and the related
+    # symbol will be yielded if a match is found. If no match is found, default symbol is yielded.
+    patterns {
+      # symbol_name = "pattern";
+      JUST_EICAR = "^Eicar-Test-Signature$";
+    }
+    # `whitelist` points to a map of IP addresses. Mail from these addresses is not scanned.
+    whitelist = "/etc/rspamd/antivirus.wl";
+  }
+}
+]])
+  return
+end
+
+
+local function add_scanner_rule(sym, opts)
+  if not opts['type'] then
+    rspamd_logger.errx(rspamd_config, 'unknown type for external scanner rule %s', sym)
+    return nil
+  end
+
+  if not opts['symbol'] then opts['symbol'] = sym:upper() end
+  local cfg = lua_scanners[opts['type']]
+
+  if not cfg then
+    rspamd_logger.errx(rspamd_config, 'unknown antivirus type: %s',
+        opts['type'])
+    return nil
+  end
+
+  if not opts['symbol_fail'] then
+    opts['symbol_fail'] = string.upper(opts['type']) .. '_FAIL'
+  end
+
+  local rule = cfg.configure(opts)
+  rule.type = opts.type
+  rule.symbol_fail = opts.symbol_fail
+  rule.redis_params = redis_params
+
+  if not rule then
+    rspamd_logger.errx(rspamd_config, 'cannot configure %s for %s',
+      opts['type'], opts['symbol'])
+    return nil
+  end
+
+  if type(opts['patterns']) == 'table' then
+    rule['patterns'] = {}
+    if opts['patterns'][1] then
+      for i, p in ipairs(opts['patterns']) do
+        if type(p) == 'table' then
+          local new_set = {}
+          for k, v in pairs(p) do
+            new_set[k] = rspamd_regexp.create_cached(v)
+          end
+          rule['patterns'][i] = new_set
+        else
+          rule['patterns'][i] = {}
+        end
+      end
+    else
+      for k, v in pairs(opts['patterns']) do
+        rule['patterns'][k] = rspamd_regexp.create_cached(v)
+      end
+    end
+  end
+
+  if opts['whitelist'] then
+    rule['whitelist'] = rspamd_config:add_hash_map(opts['whitelist'])
+  end
+
+  return function(task)
+    cfg.check(task, task:get_content(), task:get_digest(), rule)
+  end
+end
+
+-- Registration
+local opts = rspamd_config:get_all_opt(N)
+if opts and type(opts) == 'table' then
+  redis_params = rspamd_parse_redis_server(N)
+  local has_valid = false
+  for k, m in pairs(opts) do
+    if type(m) == 'table' and m.servers then
+      if not m.type then m.type = k end
+      local cb = add_scanner_rule(k, m)
+
+      if not cb then
+        rspamd_logger.errx(rspamd_config, 'cannot add rule: "' .. k .. '"')
+      else
+        local id = rspamd_config:register_symbol({
+          type = 'normal',
+          name = m['symbol'],
+          callback = cb,
+          score = 0.0,
+          group = N
+        })
+        rspamd_config:register_symbol({
+          type = 'virtual',
+          name = m['symbol_fail'],
+          parent = id,
+          score = 0.0,
+          group = N
+        })
+        has_valid = true
+        if type(m['patterns']) == 'table' then
+          if m['patterns'][1] then
+            for _, p in ipairs(m['patterns']) do
+              if type(p) == 'table' then
+                for sym in pairs(p) do
+                  rspamd_logger.debugm(N, rspamd_config, 'registering: %1', {
+                    type = 'virtual',
+                    name = sym,
+                    parent = m['symbol'],
+                    parent_id = id,
+                  })
+                  rspamd_config:register_symbol({
+                    type = 'virtual',
+                    name = sym,
+                    parent = id,
+                    group = N
+                  })
+                end
+              end
+            end
+          else
+            for sym in pairs(m['patterns']) do
+              rspamd_config:register_symbol({
+                type = 'virtual',
+                name = sym,
+                parent = id,
+                group = N
+              })
+            end
+          end
+        end
+        if m['score'] then
+          -- Register metric symbol
+          local description = 'external services symbol'
+          local group = N
+          if m['description'] then
+            description = m['description']
+          end
+          if m['group'] then
+            group = m['group']
+          end
+          rspamd_config:set_metric_symbol({
+            name = m['symbol'],
+            score = m['score'],
+            description = description,
+            group = group
+          })
+        end
+      end
+    end
+  end
+
+  if not has_valid then
+    lua_util.disable_module(N, 'config')
+  end
+end