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authorVsevolod Stakhov <vsevolod@highsecure.ru>2019-11-26 16:30:48 +0000
committerVsevolod Stakhov <vsevolod@highsecure.ru>2019-11-26 16:30:48 +0000
commit69b1c2e53f9427a6529f4a1b296de8f8f1ee7322 (patch)
tree834d81f279fef1aa9546fdcc8722950f28fe9f63
parentd055682d58ee60a67cb4efcb7448309935fd50db (diff)
downloadrspamd-69b1c2e53f9427a6529f4a1b296de8f8f1ee7322.tar.gz
rspamd-69b1c2e53f9427a6529f4a1b296de8f8f1ee7322.zip
[Project] Lua_content: Add some pdf support
-rw-r--r--lualib/lua_content/init.lua6
-rw-r--r--lualib/lua_content/pdf.lua126
2 files changed, 132 insertions, 0 deletions
diff --git a/lualib/lua_content/init.lua b/lualib/lua_content/init.lua
index 06d509e00..c23ca9d09 100644
--- a/lualib/lua_content/init.lua
+++ b/lualib/lua_content/init.lua
@@ -31,6 +31,12 @@ local content_modules = {
extensions = {'ical'},
output = "text"
},
+ pdf = {
+ mime_type = "application/pdf",
+ module = require "lua_content/pdf",
+ extensions = {'pdf'},
+ output = "table"
+ },
}
local modules_by_mime_type
diff --git a/lualib/lua_content/pdf.lua b/lualib/lua_content/pdf.lua
new file mode 100644
index 000000000..9ff3d0260
--- /dev/null
+++ b/lualib/lua_content/pdf.lua
@@ -0,0 +1,126 @@
+--[[
+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.
+]]--
+
+--[[[
+-- @module lua_content/pdf
+-- This module contains some heuristics for PDF files
+--]]
+
+local rspamd_trie = require "rspamd_trie"
+local bit = require "bit"
+local pdf_trie
+local N = "lua_content"
+local lua_util = require "lua_util"
+local pdf_patterns = {
+ trailer = {
+ patterns = {
+ [[\ntrailer\r?\n]]
+ }
+ }
+}
+
+-- index[n] ->
+-- t[1] - pattern,
+-- t[2] - key in patterns table,
+-- t[3] - value in patterns table
+-- t[4] - local pattern index
+local pdf_indexes = {}
+local exports = {}
+
+-- Used to process patterns found in PDF
+-- positions for functional processors should be a iter/table from trie matcher in form
+---- [{n1, pat_idx1}, ... {nn, pat_idxn}] where
+---- pat_idxn is pattern index and n1 ... nn are match positions
+local processors = {}
+
+local function compile_tries()
+ local default_compile_flags = bit.bor(rspamd_trie.flags.re,
+ rspamd_trie.flags.dot_all,
+ rspamd_trie.flags.single_match,
+ rspamd_trie.flags.no_start)
+ local function compile_pats(patterns, indexes, compile_flags)
+ local strs = {}
+ for what,data in pairs(patterns) do
+ for i,pat in ipairs(data.patterns) do
+ strs[#strs + 1] = pat
+ indexes[#indexes + 1] = {what, data, pat, i}
+ end
+ end
+
+ return rspamd_trie.create(strs, compile_flags or default_compile_flags)
+ end
+
+ if not pdf_trie then
+ pdf_trie = compile_pats(pdf_patterns, pdf_indexes)
+ end
+end
+
+-- Call immediately on require
+compile_tries()
+
+local function process_pdf(input, _, task)
+ local matches = pdf_trie:match(input)
+ local pdf_output = {}
+
+ if matches then
+ local grouped_processors = {}
+ for npat,matched_positions in pairs(matches) do
+ local index = pdf_indexes[npat]
+
+ local proc_key,loc_npat = index[1], index[4]
+
+ if not grouped_processors[proc_key] then
+ grouped_processors[proc_key] = {
+ processor_func = processors[proc_key],
+ offsets = {},
+ }
+ end
+ local proc = grouped_processors[proc_key]
+ -- Fill offsets
+ for _,pos in ipairs(matched_positions) do
+ proc.offsets[#proc.offsets + 1] = {pos, loc_npat}
+ end
+ end
+
+ for name,processor in pairs(grouped_processors) do
+ -- Sort by offset
+ lua_util.debugm(N, task, "pdf: process group %s with %s matches",
+ name, #processor.offsets)
+ table.sort(processor.offsets, function(e1, e2) return e1[1] < e2[1] end)
+ processor.processor_func(input, task, processor.offsets, pdf_output)
+ end
+
+ return pdf_output
+ end
+end
+
+-- Processes the PDF trailer
+processors.trailer = function(input, task, positions, output)
+ local last_pos = positions[#positions]
+
+ local last_span = input:span(last_pos[1])
+ for line in last_span:lines(true) do
+ if line:find('/Encrypt ') then
+ lua_util.debugm(N, task, "pdf: found encrypted line in trailer: %s",
+ line)
+ output.encrypted = true
+ end
+ end
+end
+
+exports.process = process_pdf
+
+return exports \ No newline at end of file