This file is indexed.

/usr/share/lua/5.1/socket/smtp.lua is in lua-socket 3.0~rc1-3.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
-----------------------------------------------------------------------------
-- SMTP client support for the Lua language.
-- LuaSocket toolkit.
-- Author: Diego Nehab
-----------------------------------------------------------------------------

-----------------------------------------------------------------------------
-- Declare module and import dependencies
-----------------------------------------------------------------------------
local base = _G
local coroutine = require("coroutine")
local string = require("string")
local math = require("math")
local os = require("os")
local socket = require("socket")
local tp = require("socket.tp")
local ltn12 = require("ltn12")
local headers = require("socket.headers")
local mime = require("mime")

socket.smtp = {}
local _M = socket.smtp

-----------------------------------------------------------------------------
-- Program constants
-----------------------------------------------------------------------------
-- timeout for connection
_M.TIMEOUT = 60
-- default server used to send e-mails
_M.SERVER = "localhost"
-- default port
_M.PORT = 25
-- domain used in HELO command and default sendmail
-- If we are under a CGI, try to get from environment
_M.DOMAIN = os.getenv("SERVER_NAME") or "localhost"
-- default time zone (means we don't know)
_M.ZONE = "-0000"

---------------------------------------------------------------------------
-- Low level SMTP API
-----------------------------------------------------------------------------
local metat = { __index = {} }

function metat.__index:greet(domain)
    self.try(self.tp:check("2.."))
    self.try(self.tp:command("EHLO", domain or _M.DOMAIN))
    return socket.skip(1, self.try(self.tp:check("2..")))
end

function metat.__index:mail(from)
    self.try(self.tp:command("MAIL", "FROM:" .. from))
    return self.try(self.tp:check("2.."))
end

function metat.__index:rcpt(to)
    self.try(self.tp:command("RCPT", "TO:" .. to))
    return self.try(self.tp:check("2.."))
end

function metat.__index:data(src, step)
    self.try(self.tp:command("DATA"))
    self.try(self.tp:check("3.."))
    self.try(self.tp:source(src, step))
    self.try(self.tp:send("\r\n.\r\n"))
    return self.try(self.tp:check("2.."))
end

function metat.__index:quit()
    self.try(self.tp:command("QUIT"))
    return self.try(self.tp:check("2.."))
end

function metat.__index:close()
    return self.tp:close()
end

function metat.__index:login(user, password)
    self.try(self.tp:command("AUTH", "LOGIN"))
    self.try(self.tp:check("3.."))
    self.try(self.tp:send(mime.b64(user) .. "\r\n"))
    self.try(self.tp:check("3.."))
    self.try(self.tp:send(mime.b64(password) .. "\r\n"))
    return self.try(self.tp:check("2.."))
end

function metat.__index:plain(user, password)
    local auth = "PLAIN " .. mime.b64("\0" .. user .. "\0" .. password)
    self.try(self.tp:command("AUTH", auth))
    return self.try(self.tp:check("2.."))
end

function metat.__index:auth(user, password, ext)
    if not user or not password then return 1 end
    if string.find(ext, "AUTH[^\n]+LOGIN") then
        return self:login(user, password)
    elseif string.find(ext, "AUTH[^\n]+PLAIN") then
        return self:plain(user, password)
    else
        self.try(nil, "authentication not supported")
    end
end

-- send message or throw an exception
function metat.__index:send(mailt)
    self:mail(mailt.from)
    if base.type(mailt.rcpt) == "table" then
        for i,v in base.ipairs(mailt.rcpt) do
            self:rcpt(v)
        end
    else
        self:rcpt(mailt.rcpt)
    end
    self:data(ltn12.source.chain(mailt.source, mime.stuff()), mailt.step)
end

function _M.open(server, port, create)
    local tp = socket.try(tp.connect(server or _M.SERVER, port or _M.PORT,
        _M.TIMEOUT, create))
    local s = base.setmetatable({tp = tp}, metat)
    -- make sure tp is closed if we get an exception
    s.try = socket.newtry(function()
        s:close()
    end)
    return s
end

-- convert headers to lowercase
local function lower_headers(headers)
    local lower = {}
    for i,v in base.pairs(headers or lower) do
        lower[string.lower(i)] = v
    end
    return lower
end

---------------------------------------------------------------------------
-- Multipart message source
-----------------------------------------------------------------------------
-- returns a hopefully unique mime boundary
local seqno = 0
local function newboundary()
    seqno = seqno + 1
    return string.format('%s%05d==%05u', os.date('%d%m%Y%H%M%S'),
        math.random(0, 99999), seqno)
end

-- send_message forward declaration
local send_message

-- yield the headers all at once, it's faster
local function send_headers(tosend)
    local canonic = headers.canonic
    local h = "\r\n"
    for f,v in base.pairs(tosend) do
        h = (canonic[f] or f) .. ': ' .. v .. "\r\n" .. h
    end
    coroutine.yield(h)
end

-- yield multipart message body from a multipart message table
local function send_multipart(mesgt)
    -- make sure we have our boundary and send headers
    local bd = newboundary()
    local headers = lower_headers(mesgt.headers or {})
    headers['content-type'] = headers['content-type'] or 'multipart/mixed'
    headers['content-type'] = headers['content-type'] ..
        '; boundary="' ..  bd .. '"'
    send_headers(headers)
    -- send preamble
    if mesgt.body.preamble then
        coroutine.yield(mesgt.body.preamble)
        coroutine.yield("\r\n")
    end
    -- send each part separated by a boundary
    for i, m in base.ipairs(mesgt.body) do
        coroutine.yield("\r\n--" .. bd .. "\r\n")
        send_message(m)
    end
    -- send last boundary
    coroutine.yield("\r\n--" .. bd .. "--\r\n\r\n")
    -- send epilogue
    if mesgt.body.epilogue then
        coroutine.yield(mesgt.body.epilogue)
        coroutine.yield("\r\n")
    end
end

-- yield message body from a source
local function send_source(mesgt)
    -- make sure we have a content-type
    local headers = lower_headers(mesgt.headers or {})
    headers['content-type'] = headers['content-type'] or
        'text/plain; charset="iso-8859-1"'
    send_headers(headers)
    -- send body from source
    while true do
        local chunk, err = mesgt.body()
        if err then coroutine.yield(nil, err)
        elseif chunk then coroutine.yield(chunk)
        else break end
    end
end

-- yield message body from a string
local function send_string(mesgt)
    -- make sure we have a content-type
    local headers = lower_headers(mesgt.headers or {})
    headers['content-type'] = headers['content-type'] or
        'text/plain; charset="iso-8859-1"'
    send_headers(headers)
    -- send body from string
    coroutine.yield(mesgt.body)
end

-- message source
function send_message(mesgt)
    if base.type(mesgt.body) == "table" then send_multipart(mesgt)
    elseif base.type(mesgt.body) == "function" then send_source(mesgt)
    else send_string(mesgt) end
end

-- set defaul headers
local function adjust_headers(mesgt)
    local lower = lower_headers(mesgt.headers)
    lower["date"] = lower["date"] or
        os.date("!%a, %d %b %Y %H:%M:%S ") .. (mesgt.zone or _M.ZONE)
    lower["x-mailer"] = lower["x-mailer"] or socket._VERSION
    -- this can't be overriden
    lower["mime-version"] = "1.0"
    return lower
end

function _M.message(mesgt)
    mesgt.headers = adjust_headers(mesgt)
    -- create and return message source
    local co = coroutine.create(function() send_message(mesgt) end)
    return function()
        local ret, a, b = coroutine.resume(co)
        if ret then return a, b
        else return nil, a end
    end
end

---------------------------------------------------------------------------
-- High level SMTP API
-----------------------------------------------------------------------------
_M.send = socket.protect(function(mailt)
    local s = _M.open(mailt.server, mailt.port, mailt.create)
    local ext = s:greet(mailt.domain)
    s:auth(mailt.user, mailt.password, ext)
    s:send(mailt)
    s:quit()
    return s:close()
end)

return _M