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    SubjectRe: [PATCH] Patch for invisible threads
    On Thu, Sep 15, 2005 at 07:54:56PM -0500, Sripathi Kodi wrote:
    > proc_root_link and proc_task_root_link still have some duplicated code. I
    > could have split these functions further to avoid duplication completely,
    > but that would move incrementing and decrementing fs->lock to two different
    > functions, which I think will be confusing.
    > The other way of implementing this that I could think of was to have a flag
    > to indicate that the call is from ->permission path and pass it all along.
    > This will avoid having to change many existing functions, but it will
    > defeat the purpose of limiting this kludge code to ->permission path.
    > Please let me know how it is looking now.

    Ugh... Considering that all of that is _only_ for /proc/<pid>/task and
    that proc_permission() is a couple of function calls, why bother with
    proc_task_check_root() instead of just adding proc_task_permission() with

    struct dentry *root;
    struct vfsmount *vfsmnt;

    if (generic_permission(inode, mask, NULL) != 0)
    return -EACCES;

    /* or just open-code it here, for that matter */
    if (proc_task_root_link(inode, &root, &vfsmnt))
    return -ENOENT;

    return proc_check_chroot(root, vfsmnt);

    for a body and leaving proc_permission() without any changes at all?

    > Further, about actual permission checks that we are doing, can we say: "A
    > process should be able to see /proc/<pid>/task/* of another process only if
    > they both belong to same uid or reader is root"? But any such change will
    > change the behavior of commands like 'ps', right?

    Right. The real question is whether the current behaviour makes any sense.
    I've no objections to your patch + modification above, but I really wonder
    if we should keep current rules in that area.
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      Last update: 2005-09-16 09:49    [W:1.338 / U:2.480 seconds]
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