libs/web/luasrc/sauth.lua

   1 --[[
   2
   3 Session authentication
   4 (c) 2008 Steven Barth <steven@midlink.org>
   5
   6 Licensed under the Apache License, Version 2.0 (the "License");
   7 you may not use this file except in compliance with the License.
   8 You may obtain a copy of the License at
   9
  10         http://www.apache.org/licenses/LICENSE-2.0
  11
  12 $Id$
  13
  14 ]]--
  15
  16 --- LuCI session library.
  17 module("luci.sauth", package.seeall)
  18 require("luci.util")
  19 require("luci.sys")
  20 require("luci.config")
  21 local nixio = require "nixio", require "nixio.util"
  22 local fs = require "nixio.fs"
  23
  24
  25 luci.config.sauth = luci.config.sauth or {}
  26 sessionpath = luci.config.sauth.sessionpath
  27 sessiontime = tonumber(luci.config.sauth.sessiontime) or 15 * 60
  28
  29 --- Manually clean up expired sessions.
  30 function clean()
  31         local now   = os.time()
  32         local files = fs.dir(sessionpath)
  33
  34         if not files then
  35                 return nil
  36         end
  37
  38         for file in files do
  39                 local fname = sessionpath .. "/" .. file
  40                 local stat = fs.stat(fname)
  41                 if stat and stat.type == "reg" and stat.mtime + sessiontime < now then
  42                         fs.unlink(fname)
  43                 end
  44         end
  45 end
  46
  47 --- Prepare session storage by creating the session directory.
  48 function prepare()
  49         fs.mkdir(sessionpath, 700)
  50
  51         if not sane() then
  52                 error("Security Exception: Session path is not sane!")
  53         end
  54 end
  55
  56 --- Read a session and return its content.
  57 -- @param id    Session identifier
  58 -- @return              Session data
  59 function read(id)
  60         if not id then
  61                 return
  62         end
  63         if not id:match("^%w+$") then
  64                 error("Session ID is not sane!")
  65         end
  66         clean()
  67         if not sane(sessionpath .. "/" .. id) then
  68                 return
  69         end
  70         fs.utimes(sessionpath .. "/" .. id)
  71         return fs.readfile(sessionpath .. "/" .. id)
  72 end
  73
  74
  75 --- Check whether Session environment is sane.
  76 -- @return Boolean status
  77 function sane(file)
  78         return luci.sys.process.info("uid")
  79                         == fs.stat(file or sessionpath, "uid")
  80                 and fs.stat(file or sessionpath, "modestr")
  81                         == (file and "rw-------" or "rwx------")
  82 end
  83
  84
  85 --- Write session data to a session file.
  86 -- @param id    Session identifier
  87 -- @param data  Session data
  88 function write(id, data)
  89         if not sane() then
  90                 prepare()
  91         end
  92         if not id:match("^%w+$") then
  93                 error("Session ID is not sane!")
  94         end
  95
  96         local f = nixio.open(sessionpath .. "/" .. id, "w", 600)
  97         f:writeall(data)
  98         f:close()
  99 end
 100
 101
 102 --- Kills a session
 103 -- @param id    Session identifier
 104 function kill(id)
 105         if not id:match("^%w+$") then
 106                 error("Session ID is not sane!")
 107         end
 108         fs.unlink(sessionpath .. "/" .. id)
 109 end