lkml.org 
[lkml]   [2002]   [Apr]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH] module locking
    At 08:30 29/04/02, Rolf Fokkens wrote:
    >On Monday 29 April 2002 09:23, Thomas 'Dent' Mirlacher wrote:
    > > the capable call is sthell there, but with the module_lock
    > > kind or redundant.
    >
    >once set module_lock cannot be cleared, not even by root. This differs from
    >the CAP_SYS_MODULE which can be activated by root, if I'm correct.
    >
    >module_lock is only a suggestion, w/o /dev/kmem write locking or even
    >locking writes on other /dev/.. or doing mounts it won't be full proof.

    *sigh*

    RTFM man 2 sysctl

    With your patch applied AND module_lock set to 1, anyone with sufficient
    privileges could still do:

    #include <linux/unistd.h>
    #include <linux/types.h>
    #include <linux/sysctl.h>

    _syscall1(int, _sysctl, struct __sysctl_args *, args);
    #define SIZE(x) sizeof(x)/sizeof(x[0])

    int main(void)
    {
    int name[] = { CTL_KERN, KERN_MODPROBE };
    int hack = 0;
    struct __sysctl_args args = { name, SIZE(name), 0, 0,
    &hack, sizeof(hack) };

    if (_sysctl(&args)) {
    perror("sysctl failed");
    exit(1);
    }
    printf("module_lock has been zeroed! Muahaha!");
    return 0;
    }

    Good bye module_lock! /me waves

    What was that about not being able to zero it again...?

    Best regards,

    Anton


    --
    "I've not lost my mind. It's backed up on tape somewhere." - Unknown
    --
    Anton Altaparmakov <aia21 at cantab.net> (replace at with @)
    Linux NTFS Maintainer / IRC: #ntfs on irc.openprojects.net
    WWW: http://linux-ntfs.sf.net/ & http://www-stu.christs.cam.ac.uk/~aia21/

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 13:25    [W:0.031 / U:60.036 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site