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
  23
  24 luci.config.sauth = luci.config.sauth or {}
  25 sessionpath = luci.config.sauth.sessionpath
  26 sessiontime = tonumber(luci.config.sauth.sessiontime) or 15 * 60
  27
  28 --- Manually clean up expired sessions.
  29 function clean()
  30         local now   = os.time()
  31         local files = luci.fs.dir(sessionpath)
  32
  33         if not files then
  34                 return nil
  35         end
  36
  37         for i, file in pairs(files) do
  38                 local fname = sessionpath .. "/" .. file
  39                 local stat = luci.fs.stat(fname)
  40                 if stat and stat.type == "regular" and stat.atime + sessiontime < now then
  41                         luci.fs.unlink(fname)
  42                 end
  43         end
  44 end
  45
  46 --- Prepare session storage by creating the session directory.
  47 function prepare()
  48         luci.fs.mkdir(sessionpath)
  49         luci.fs.chmod(sessionpath, "a-rwx,u+rwx")
  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+$") then
  64                 error("Session ID is not sane!")
  65         end
  66         clean()
  67         if not sane(sessionpath .. "/" .. id) then
  68                 return
  69         end
  70         return luci.fs.readfile(sessionpath .. "/" .. id)
  71 end
  72
  73
  74 --- Check whether Session environment is sane.
  75 -- @return Boolean status
  76 function sane(file)
  77         return luci.sys.process.info("uid")
  78                         == luci.fs.stat(file or sessionpath, "uid")
  79                 and luci.fs.stat(file or sessionpath, "mode")
  80                         == (file and "rw-------" or "rwx------")
  81 end
  82
  83
  84 --- Write session data to a session file.
  85 -- @param id    Session identifier
  86 -- @param data  Session data
  87 function write(id, data)
  88         if not sane() then
  89                 prepare()
  90         end
  91         if not id:match("^%w+$") then
  92                 error("Session ID is not sane!")
  93         end
  94         luci.fs.writefile(sessionpath .. "/" .. id, data)
  95         luci.fs.chmod(sessionpath .. "/" .. id, "a-rwx,u+rw")
  96 end
  97
  98
  99 --- Kills a session
 100 -- @param id    Session identifier
 101 function kill(id)
 102         if not id:match("^%w+$") then
 103                 error("Session ID is not sane!")
 104         end
 105         luci.fs.unlink(sessionpath .. "/" .. id)
 106 end