Re: Another version of stacker.c (URL attached)

From: Chris Wright (chrisat_private)
Date: Mon Jul 22 2002 - 12:18:55 PDT

  • Next message: Greg KH: "[BK PATCH] LSM changes for 2.5.27"

    * Lachlan McIlroy (lachlanat_private) wrote:
    > 
    > There is a problem with unloading subordinate modules while
    > another process is executing one of its hooks.  This can even
    > happen on uniprocessor systems if a process is sleeping in a
    > hook.  When the module is removed from memory the other
    > process will cause an oops or panic when it continues.  One
    
    This problem exists w/out the multiplexor module.  You have two choices.
    Live with the danger.  Or MOD_INC_USE_COUNT upon module_init() (before
    loading the security_ops) so that you really can't unload the module.
    A scheme like you've outlined will work (in the multiplexor module), and
    in fact, can be generalized and optimized to work in the non-stacked case.
    But corner cases still exist, and the overhead isn't mitigated by the
    usefulness.  See Rusty's evil module unloading talk ;-)
    
    thanks,
    -chris
    -- 
    Linux Security Modules     http://lsm.immunix.org     http://lsm.bkbits.net
    _______________________________________________
    linux-security-module mailing list
    linux-security-moduleat_private
    http://mail.wirex.com/mailman/listinfo/linux-security-module
    



    This archive was generated by hypermail 2b30 : Mon Jul 22 2002 - 12:20:39 PDT