libs/web: Add additional sanity checks to session mechanism

diff --git a/libs/web/luasrc/sauth.lua b/libs/web/luasrc/sauth.lua
index d25f287c5a030095a43a73171eb5c0ba7d387e5b..8182679ce78d2a7356990e4cb2ad7ed362879c5d 100644 (file)
--- a/libs/web/luasrc/sauth.lua
+++ b/libs/web/luasrc/sauth.lua
@@ -45,14 +45,16 @@ end
 --- Prepare session storage by creating the session directory.
 function prepare()
        luci.fs.mkdir(sessionpath)
-       luci.fs.chmod(sessionpath, "a-rwx,u+rwx")
+       if not luci.fs.chmod(sessionpath, "a-rwx,u+rwx") then
+               error("Security Exception: Session path is not sane!")
+       end
 end
 
 --- Read a session and return its content.
 -- @param id   Session identifier
 -- @return             Session data
 function read(id)
-       if not id then
+       if not id or not sane() then
                return
        end
        clean()
@@ -60,11 +62,18 @@ function read(id)
 end
 
 
+--- Check whether Session environment is sane.
+-- @return Boolean status
+function sane()
+       return luci.fs.stat(sessionpath, "mode") == "rwx------"
+end
+
+
 --- Write session data to a session file.
 -- @param id   Session identifier
 -- @param data Session data
 function write(id, data)
-       if not luci.fs.stat(sessionpath) then
+       if not sane() then
                prepare()
        end
        luci.fs.writefile(sessionpath .. "/" .. id, data)