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    Subjectmodule loading with CAP_NET_ADMIN
    Hi netdev folks,

    I'd like to discuss the ability to load any modules from /lib/modules/
    by a process with CAP_NET_ADMIN. Since Linux 2.6.32 [1] there is such
    possibility:

    root@albatros:~# grep Cap /proc/$$/status
    CapInh: 0000000000000000
    CapPrm: fffffffc00001000
    CapEff: fffffffc00001000
    CapBnd: fffffffc00001000
    root@albatros:~# lsmod | grep xfs
    root@albatros:~# ifconfig xfs
    xfs: error fetching interface information: Device not found
    root@albatros:~# lsmod | grep xfs
    xfs 767011 0
    exportfs 4226 2 xfs,nfsd

    Ability of CAP_NET_ADMIN to load the driver to work with a particular
    network device is rational; however, one may load any module not even
    related to network this way. Hopefully, this is not equal to
    CAP_SYS_MODULE since the module set is restricted to /lib/modules
    (additionally may be disabled with /proc/sys/kernel/modules_disabled),
    but the idea of non-netdev module loading is weird.

    My proposal is changing request_module("%s", name) to something like
    request_module("netdev-%s", name) inside of dev_load() and adding
    aliases to related drivers. This would allow to load only netdev
    modules via these ioctls. I'm not sure what modules should be patches -
    at least real physical netdevices have names different from drivers'
    names, so they don't need patching. I suppose the list is not big.

    Any comments are welcome.


    [1] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=a8f80e8ff94ecba629542d9b4b5f5a8ee3eb565c


    Thanks,

    --
    Vasiliy Kulikov
    http://www.openwall.com - bringing security into open computing environments


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