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-- Licensed to the Apache Software Foundation (ASF) under one or more
-- contributor license agreements. See the NOTICE file distributed with
-- this work for additional information regarding copyright ownership.
-- The ASF licenses this file to you 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 reconf = config['regexp']
local rspamd_regexp = require "rspamd_regexp"
local rspamd_logger = require "rspamd_logger"
-- Messages that have only HTML part
reconf['MIME_HTML_ONLY'] = 'has_only_html_part()'
local function check_html_image(task, min, max)
local tp = task:get_text_parts()
for _,p in ipairs(tp) do
if p:is_html() then
local hc = p:get_html()
local len = p:get_length()
if hc and len >= min and len < max then
local images = hc:get_images()
if images then
for _,i in ipairs(images) do
local tag = i['tag']
if tag then
local parent = tag:get_parent()
if parent then
if parent:get_type() == 'a' then
-- do not trigger on small and unknown size images
if i['height'] + i['width'] >= 210 or not i['embedded'] then
return true
end
end
end
end
end
end
end
end
end
end
rspamd_config.HTML_SHORT_LINK_IMG_1 = {
callback = function(task)
return check_html_image(task, 0, 1024)
end,
score = 3.0,
group = 'html',
description = 'Short html part (0..1K) with a link to an image'
}
rspamd_config.HTML_SHORT_LINK_IMG_2 = {
callback = function(task)
return check_html_image(task, 1024, 1536)
end,
score = 1.0,
group = 'html',
description = 'Short html part (1K..1.5K) with a link to an image'
}
rspamd_config.HTML_SHORT_LINK_IMG_3 = {
callback = function(task)
return check_html_image(task, 1536, 2048)
end,
score = 0.5,
group = 'html',
description = 'Short html part (1.5K..2K) with a link to an image'
}
rspamd_config.R_EMPTY_IMAGE = {
callback = function(task)
local tp = task:get_text_parts() -- get text parts in a message
for _,p in ipairs(tp) do -- iterate over text parts array using `ipairs`
if p:is_html() then -- if the current part is html part
local hc = p:get_html() -- we get HTML context
local len = p:get_length() -- and part's length
if hc and len < 50 then -- if we have a part that has less than 50 bytes of text
local images = hc:get_images() -- then we check for HTML images
if images then -- if there are images
for _,i in ipairs(images) do -- then iterate over images in the part
if i['height'] + i['width'] >= 400 then -- if we have a large image
local tag = i['tag']
if tag then
local parent = tag:get_parent()
if parent then
if parent:get_type() ~= 'a' then
return true
end
end
end
end
end
end
end
end
end
end,
score = 2.0,
group = 'html',
description = 'Message contains empty parts and image'
}
rspamd_config.R_SUSPICIOUS_IMAGES = {
callback = function(task)
local tp = task:get_text_parts() -- get text parts in a message
for _, p in ipairs(tp) do
local h = p:get_html()
if h then
local l = p:get_words_count()
local img = h:get_images()
local pic_words = 0
if img then
for _, i in ipairs(img) do
local dim = i['width'] + i['height']
local tag = i['tag']
if tag then
local parent = tag:get_parent()
if parent then
if parent:get_type() == 'a' then
-- do not trigger on small and large images
if dim > 100 and dim < 3000 then
-- We assume that a single picture 100x200 contains approx 3 words of text
pic_words = pic_words + dim / 100
end
end
end
end
end
end
if l + pic_words > 0 then
local rel = pic_words / (l + pic_words)
if rel > 0.5 then
return true, (rel - 0.5) * 2
end
end
end
end
return false
end,
score = 5.0,
group = 'html',
description = 'Message contains many suspicious messages'
}
rspamd_config.R_WHITE_ON_WHITE = {
callback = function(task)
local tp = task:get_text_parts() -- get text parts in a message
local ret = false
local diff = 0.0
local normal_len = 0
local transp_len = 0
local arg
for _,p in ipairs(tp) do -- iterate over text parts array using `ipairs`
if p:is_html() and p:get_html() then -- if the current part is html part
normal_len = p:get_length()
local hc = p:get_html() -- we get HTML context
hc:foreach_tag('font', function(tag, len)
local bl = tag:get_extra()
if bl then
if bl['bgcolor'] and bl['color'] then
local color = bl['color']
local bgcolor = bl['bgcolor']
-- Should use visual approach here some day
local diff_r = math.abs(color[1] - bgcolor[1]) / 255.0
local diff_g = math.abs(color[2] - bgcolor[2]) / 255.0
local diff_b = math.abs(color[3] - bgcolor[3]) / 255.0
diff = (diff_r + diff_g + diff_b) / 3.0
if diff < 0.1 then
ret = true
transp_len = (transp_len + tag:get_content_length()) *
(0.1 - diff) * 5.0
normal_len = normal_len - tag:get_content_length()
if not arg then
arg = string.format('%s color #%x%x%x bgcolor #%x%x%x',
tostring(tag:get_type()),
color[1], color[2], color[3],
bgcolor[1], bgcolor[2], bgcolor[3])
end
else
end
end
end
return false -- Continue search
end)
end
end
if ret then
if normal_len < 0 then normal_len = 0 end
local transp_rate = transp_len / (normal_len + transp_len)
if transp_rate > 0.1 then
return true,(transp_rate * 2.0),arg
end
end
return false
end,
score = 6.0,
group = 'html',
description = 'Message contains low contrast text'
}
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