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    Subject[RFLART] kdev_t in ioctls
    	Linus, at least some ioctls (e.g. lvm ones) pass kdev_t from/to
    userland. While the common policy with ioctls is "anything goes", this
    kind of abuse is IMNSHO over the top.

    Example: ioctl(fd, VG_CREATE, ptr) expects the following:
    at ptr -
    struct {
    /* bunch of sane fields */
    struct proc_dir_entry *proc; /* ignored */
    pv_t *pv[ABS_MAX_PV + 1];
    lv_t *lv[ABS_MAX_LV + 1];
    /* bunch of stuff */

    and pointers in the second array are to the following:
    struct {
    /* lots of stuff */
    kdev_t lv_dev;
    /* lots of other stuff */

    They _are_ dereferenced and values of ptr->lv[i]->lv_dev are stored in
    kernel data structures. And used afterwards. As kdev_t.

    The same goes for the rest of LVM ioctls - pretty much all of them
    pull such stunts. I'm not going to comment on harmless gross indecencies
    like struct proc_dir_entry * passed from the userland (and fortunately
    ignored), but kdev_t instances are _not_ harmless.

    Public statement along the lines "any API that passes kdev_t values
    across the kernel boundary is unacceptable" would be a nice thing...

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      Last update: 2005-03-22 13:15    [W:0.022 / U:1.748 seconds]
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