[Bug 206678] OGIO_KEYMAP command does not restore priority level

bugzilla-noreply at freebsd.org bugzilla-noreply at freebsd.org
Wed Jan 27 15:05:42 UTC 2016


            Bug ID: 206678
           Summary: OGIO_KEYMAP command does not restore priority level
           Product: Base System
           Version: 11.0-CURRENT
          Hardware: Any
                OS: Any
            Status: New
          Severity: Affects Only Me
          Priority: ---
         Component: kern
          Assignee: freebsd-bugs at FreeBSD.org
          Reporter: ecturt at gmail.com

`genkbd_commonioctl` function from `sys/dev/kbd/kbd.c` begins by calling
`spltty()` to block hard interrupts from TTY:

genkbd_commonioctl(keyboard_t *kbd, u_long cmd, caddr_t arg)
        keymap_t *mapp;
        okeymap_t *omapp;
        keyarg_t *keyp;
        fkeyarg_t *fkeyp;splx
        int s;
        int i, j;
        int error;

        s = spltty();
        switch (cmd) {

It should always restore the original priority level using the `splx` function
before returning. For example at the end of the function:

        return (0);

And for any commands which need to return early:

        case GIO_KEYMAP:        /* get keyboard translation table */
                error = copyout(kbd->kb_keymap, *(void **)arg,
                return (error);

The problem is that for the `OGIO_KEYMAP` command, this does not happen:

        case OGIO_KEYMAP:       /* get keyboard translation table (compat) */
                mapp = kbd->kb_keymap;
                omapp = (okeymap_t *)arg;
                omapp->n_keys = mapp->n_keys;
                for (i = 0; i < NUM_KEYS; i++) {
                        for (j = 0; j < NUM_STATES; j++)
                                omapp->key[i].map[j] =
                        omapp->key[i].spcl = mapp->key[i].spcl;
                        omapp->key[i].flgs = mapp->key[i].flgs;
                return (0);

My guess is that since this is a compatibility command, it was copied into here
from somewhere else, which is why the call to `splx` is missing.

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