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--[[
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 function process_pdf_specific(task, part, specific)
local suspicious_factor = 0
if specific.encrypted then
task:insert_result('PDF_ENCRYPTED', 1.0, part:get_filename() or 'unknown')
suspicious_factor = suspicious_factor + 0.1
if specific.openaction then
suspicious_factor = suspicious_factor + 0.5
end
end
if specific.scripts then
task:insert_result('PDF_JAVASCRIPT', 1.0, part:get_filename() or 'unknown')
suspicious_factor = suspicious_factor + 0.1
end
if specific.suspicious then
suspicious_factor = suspicious_factor + 0.7
end
if suspicious_factor > 0.5 then
if suspicious_factor > 1.0 then suspicious_factor = 1.0 end
task:insert_result('PDF_SUSPICIOUS', suspicious_factor, part:get_filename() or 'unknown')
end
if specific.long_trailer then
task:insert_result('PDF_LONG_TRAILER', 1.0, string.format('%s:%d',
part:get_filename() or 'unknown', specific.long_trailer))
end
if specific.many_objects then
task:insert_result('PDF_MANY_OBJECTS', 1.0, string.format('%s:%d',
part:get_filename() or 'unknown', specific.many_objects))
end
if specific.timeout_processing then
task:insert_result('PDF_TIMEOUT', 1.0, string.format('%s:%.3f',
part:get_filename() or 'unknown', specific.timeout_processing))
end
end
local tags_processors = {
pdf = process_pdf_specific
}
local function process_specific_cb(task)
local parts = task:get_parts() or {}
for _,p in ipairs(parts) do
if p:is_specific() then
local data = p:get_specific()
if data and type(data) == 'table' and data.tag then
if tags_processors[data.tag] then
tags_processors[data.tag](task, p, data)
end
end
end
end
end
local id = rspamd_config:register_symbol{
type = 'callback',
name = 'SPECIFIC_CONTENT_CHECK',
callback = process_specific_cb
}
rspamd_config:register_symbol{
type = 'virtual',
name = 'PDF_ENCRYPTED',
parent = id,
groups = {"content", "pdf"},
}
rspamd_config:register_symbol{
type = 'virtual',
name = 'PDF_JAVASCRIPT',
parent = id,
groups = {"content", "pdf"},
}
rspamd_config:register_symbol{
type = 'virtual',
name = 'PDF_SUSPICIOUS',
parent = id,
groups = {"content", "pdf"},
}
rspamd_config:register_symbol{
type = 'virtual',
name = 'PDF_LONG_TRAILER',
parent = id,
groups = {"content", "pdf"},
}
rspamd_config:register_symbol{
type = 'virtual',
name = 'PDF_MANY_OBJECTS',
parent = id,
groups = {"content", "pdf"},
}
rspamd_config:register_symbol{
type = 'virtual',
name = 'PDF_TIMEOUT',
parent = id,
groups = {"content", "pdf"},
}
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