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.fs")
  19 require("luci.util")
  20 require("luci.sys")
  21 require("luci.config")
  22 local nixio = require "nixio", require "nixio.util"
  23 local fs = require "nixio.fs"
  24
  25
  26 luci.config.sauth = luci.config.sauth or {}
  27 sessionpath = luci.config.sauth.sessionpath
  28 sessiontime = tonumber(luci.config.sauth.sessiontime) or 15 * 60
  29
  30 --- Manually clean up expired sessions.
  31 function clean()
  32         local now   = os.time()
  33         local files = luci.fs.dir(sessionpath)
  34
  35         if not files then
  36                 return nil
  37         end
  38
  39         for i, file in pairs(files) do
  40                 local fname = sessionpath .. "/" .. file
  41                 local stat = luci.fs.stat(fname)
  42                 if stat and stat.type == "reg" and stat.mtime + sessiontime < now then
  43                         luci.fs.unlink(fname)
  44                 end
  45         end
  46 end
  47
  48 --- Prepare session storage by creating the session directory.
  49 function prepare()
  50         fs.mkdir(sessionpath, 700)
  51
  52         if not sane() then
  53                 error("Security Exception: Session path is not sane!")
  54         end
  55 end
  56
  57 --- Read a session and return its content.
  58 -- @param id    Session identifier
  59 -- @return              Session data
  60 function read(id)
  61         if not id then
  62                 return
  63         end
  64         if not id:match("^%w+$") then
  65                 error("Session ID is not sane!")
  66         end
  67         clean()
  68         if not sane(sessionpath .. "/" .. id) then
  69                 return
  70         end
  71         luci.fs.utime(sessionpath .. "/" .. id)
  72         return luci.fs.readfile(sessionpath .. "/" .. id)
  73 end
  74
  75
  76 --- Check whether Session environment is sane.
  77 -- @return Boolean status
  78 function sane(file)
  79         return luci.sys.process.info("uid")
  80                         == luci.fs.stat(file or sessionpath, "uid")
  81                 and luci.fs.stat(file or sessionpath, "modestr")
  82                         == (file and "rw-------" or "rwx------")
  83 end
  84
  85
  86 --- Write session data to a session file.
  87 -- @param id    Session identifier
  88 -- @param data  Session data
  89 function write(id, data)
  90         if not sane() then
  91                 prepare()
  92         end
  93         if not id:match("^%w+$") then
  94                 error("Session ID is not sane!")
  95         end
  96
  97         local f = nixio.open(sessionpath .. "/" .. id, "w", 600)
  98         f:writeall(data)
  99         f:close()
 100 end
 101
 102
 103 --- Kills a session
 104 -- @param id    Session identifier
 105 function kill(id)
 106         if not id:match("^%w+$") then
 107                 error("Session ID is not sane!")
 108         end
 109         luci.fs.unlink(sessionpath .. "/" .. id)
 110 end