[lkml]   [2006]   [Oct]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [patch] honour MNT_NOEXEC for access()
    Stas Sergeev  wrote:
    >Ulrich Drepper wrote:
    >>> Now, as the access(X_OK) is fixed, would it be
    >>> feasible for to start using it?
    >> Just must be kidding. No access control can be reliably implemented at
    >> userlevel. There is no point starting something as stupid as this.
    >But in this case how can you ever solve the
    >problem of executing the binaries for which
    >the user does not have an exec permission?

    By using the kernel's existing access control -- not trying to roll
    your own access control at the user level. This is a standard recommendation
    in the security world, and it is good advice.

    For instance, in this case, this advice might mean that you just call
    execve() and check whether it succeeded or failed, and let the kernel
    do the access control check on whether the exec is permitted. That tends
    to be more fool-proof (or at least fool-resistant) than the alternatives.

    >Yes, the userspace apps usually should not enforce
    >the kernel's access control, but seems to be
    >the special case - it is a kernel helper after all,
    >so it have to be carefull and check what it does.

    Perhaps. But it seems to me that there would need to be a persuasive
    argument before it makes sense to violate the general advice listed above.
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2006-10-07 21:39    [W:0.021 / U:53.996 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site