1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 1992 obz under the linux copyright
4 *
5 * Dynamic diacritical handling - aeb@cwi.nl - Dec 1993
6 * Dynamic keymap and string allocation - aeb@cwi.nl - May 1994
7 * Restrict VT switching via ioctl() - grif@cs.ucr.edu - Dec 1995
8 * Some code moved for less code duplication - Andi Kleen - Mar 1997
9 * Check put/get_user, cleanups - acme@conectiva.com.br - Jun 2001
10 */
11
12#include <linux/types.h>
13#include <linux/errno.h>
14#include <linux/sched/signal.h>
15#include <linux/tty.h>
16#include <linux/timer.h>
17#include <linux/kernel.h>
18#include <linux/compat.h>
19#include <linux/module.h>
20#include <linux/kd.h>
21#include <linux/vt.h>
22#include <linux/string.h>
23#include <linux/slab.h>
24#include <linux/major.h>
25#include <linux/fs.h>
26#include <linux/console.h>
27#include <linux/consolemap.h>
28#include <linux/signal.h>
29#include <linux/suspend.h>
30#include <linux/timex.h>
31
32#include <asm/io.h>
33#include <linux/uaccess.h>
34
35#include <linux/nospec.h>
36
37#include <linux/kbd_kern.h>
38#include <linux/vt_kern.h>
39#include <linux/kbd_diacr.h>
40#include <linux/selection.h>
41
42bool vt_dont_switch;
43
44static inline bool vt_in_use(unsigned int i)
45{
46 const struct vc_data *vc = vc_cons[i].d;
47
48 /*
49 * console_lock must be held to prevent the vc from being deallocated
50 * while we're checking whether it's in-use.
51 */
52 WARN_CONSOLE_UNLOCKED();
53
54 return vc && kref_read(kref: &vc->port.kref) > 1;
55}
56
57static inline bool vt_busy(int i)
58{
59 if (vt_in_use(i))
60 return true;
61 if (i == fg_console)
62 return true;
63 if (vc_is_sel(vc: vc_cons[i].d))
64 return true;
65
66 return false;
67}
68
69/*
70 * Console (vt and kd) routines, as defined by USL SVR4 manual, and by
71 * experimentation and study of X386 SYSV handling.
72 *
73 * One point of difference: SYSV vt's are /dev/vtX, which X >= 0, and
74 * /dev/console is a separate ttyp. Under Linux, /dev/tty0 is /dev/console,
75 * and the vc start at /dev/ttyX, X >= 1. We maintain that here, so we will
76 * always treat our set of vt as numbered 1..MAX_NR_CONSOLES (corresponding to
77 * ttys 0..MAX_NR_CONSOLES-1). Explicitly naming VT 0 is illegal, but using
78 * /dev/tty0 (fg_console) as a target is legal, since an implicit aliasing
79 * to the current console is done by the main ioctl code.
80 */
81
82#ifdef CONFIG_X86
83#include <asm/syscalls.h>
84#endif
85
86static void complete_change_console(struct vc_data *vc);
87
88/*
89 * User space VT_EVENT handlers
90 */
91
92struct vt_event_wait {
93 struct list_head list;
94 struct vt_event event;
95 int done;
96};
97
98static LIST_HEAD(vt_events);
99static DEFINE_SPINLOCK(vt_event_lock);
100static DECLARE_WAIT_QUEUE_HEAD(vt_event_waitqueue);
101
102/**
103 * vt_event_post
104 * @event: the event that occurred
105 * @old: old console
106 * @new: new console
107 *
108 * Post an VT event to interested VT handlers
109 */
110
111void vt_event_post(unsigned int event, unsigned int old, unsigned int new)
112{
113 struct list_head *pos, *head;
114 unsigned long flags;
115 int wake = 0;
116
117 spin_lock_irqsave(&vt_event_lock, flags);
118 head = &vt_events;
119
120 list_for_each(pos, head) {
121 struct vt_event_wait *ve = list_entry(pos,
122 struct vt_event_wait, list);
123 if (!(ve->event.event & event))
124 continue;
125 ve->event.event = event;
126 /* kernel view is consoles 0..n-1, user space view is
127 console 1..n with 0 meaning current, so we must bias */
128 ve->event.oldev = old + 1;
129 ve->event.newev = new + 1;
130 wake = 1;
131 ve->done = 1;
132 }
133 spin_unlock_irqrestore(lock: &vt_event_lock, flags);
134 if (wake)
135 wake_up_interruptible(&vt_event_waitqueue);
136}
137
138static void __vt_event_queue(struct vt_event_wait *vw)
139{
140 unsigned long flags;
141 /* Prepare the event */
142 INIT_LIST_HEAD(list: &vw->list);
143 vw->done = 0;
144 /* Queue our event */
145 spin_lock_irqsave(&vt_event_lock, flags);
146 list_add(new: &vw->list, head: &vt_events);
147 spin_unlock_irqrestore(lock: &vt_event_lock, flags);
148}
149
150static void __vt_event_wait(struct vt_event_wait *vw)
151{
152 /* Wait for it to pass */
153 wait_event_interruptible(vt_event_waitqueue, vw->done);
154}
155
156static void __vt_event_dequeue(struct vt_event_wait *vw)
157{
158 unsigned long flags;
159
160 /* Dequeue it */
161 spin_lock_irqsave(&vt_event_lock, flags);
162 list_del(entry: &vw->list);
163 spin_unlock_irqrestore(lock: &vt_event_lock, flags);
164}
165
166/**
167 * vt_event_wait - wait for an event
168 * @vw: our event
169 *
170 * Waits for an event to occur which completes our vt_event_wait
171 * structure. On return the structure has wv->done set to 1 for success
172 * or 0 if some event such as a signal ended the wait.
173 */
174
175static void vt_event_wait(struct vt_event_wait *vw)
176{
177 __vt_event_queue(vw);
178 __vt_event_wait(vw);
179 __vt_event_dequeue(vw);
180}
181
182/**
183 * vt_event_wait_ioctl - event ioctl handler
184 * @event: argument to ioctl (the event)
185 *
186 * Implement the VT_WAITEVENT ioctl using the VT event interface
187 */
188
189static int vt_event_wait_ioctl(struct vt_event __user *event)
190{
191 struct vt_event_wait vw;
192
193 if (copy_from_user(to: &vw.event, from: event, n: sizeof(struct vt_event)))
194 return -EFAULT;
195 /* Highest supported event for now */
196 if (vw.event.event & ~VT_MAX_EVENT)
197 return -EINVAL;
198
199 vt_event_wait(vw: &vw);
200 /* If it occurred report it */
201 if (vw.done) {
202 if (copy_to_user(to: event, from: &vw.event, n: sizeof(struct vt_event)))
203 return -EFAULT;
204 return 0;
205 }
206 return -EINTR;
207}
208
209/**
210 * vt_waitactive - active console wait
211 * @n: new console
212 *
213 * Helper for event waits. Used to implement the legacy
214 * event waiting ioctls in terms of events
215 */
216
217int vt_waitactive(int n)
218{
219 struct vt_event_wait vw;
220 do {
221 vw.event.event = VT_EVENT_SWITCH;
222 __vt_event_queue(vw: &vw);
223 if (n == fg_console + 1) {
224 __vt_event_dequeue(vw: &vw);
225 break;
226 }
227 __vt_event_wait(vw: &vw);
228 __vt_event_dequeue(vw: &vw);
229 if (vw.done == 0)
230 return -EINTR;
231 } while (vw.event.newev != n);
232 return 0;
233}
234
235/*
236 * these are the valid i/o ports we're allowed to change. they map all the
237 * video ports
238 */
239#define GPFIRST 0x3b4
240#define GPLAST 0x3df
241#define GPNUM (GPLAST - GPFIRST + 1)
242
243/*
244 * currently, setting the mode from KD_TEXT to KD_GRAPHICS doesn't do a whole
245 * lot. i'm not sure if it should do any restoration of modes or what...
246 *
247 * XXX It should at least call into the driver, fbdev's definitely need to
248 * restore their engine state. --BenH
249 *
250 * Called with the console lock held.
251 */
252static int vt_kdsetmode(struct vc_data *vc, unsigned long mode)
253{
254 switch (mode) {
255 case KD_GRAPHICS:
256 break;
257 case KD_TEXT0:
258 case KD_TEXT1:
259 mode = KD_TEXT;
260 fallthrough;
261 case KD_TEXT:
262 break;
263 default:
264 return -EINVAL;
265 }
266
267 if (vc->vc_mode == mode)
268 return 0;
269
270 vc->vc_mode = mode;
271 if (vc->vc_num != fg_console)
272 return 0;
273
274 /* explicitly blank/unblank the screen if switching modes */
275 if (mode == KD_TEXT)
276 do_unblank_screen(leaving_gfx: 1);
277 else
278 do_blank_screen(entering_gfx: 1);
279
280 return 0;
281}
282
283static int vt_k_ioctl(struct tty_struct *tty, unsigned int cmd,
284 unsigned long arg, bool perm)
285{
286 struct vc_data *vc = tty->driver_data;
287 void __user *up = (void __user *)arg;
288 unsigned int console = vc->vc_num;
289 int ret;
290
291 switch (cmd) {
292 case KIOCSOUND:
293 if (!perm)
294 return -EPERM;
295 /*
296 * The use of PIT_TICK_RATE is historic, it used to be
297 * the platform-dependent CLOCK_TICK_RATE between 2.6.12
298 * and 2.6.36, which was a minor but unfortunate ABI
299 * change. kd_mksound is locked by the input layer.
300 */
301 if (arg)
302 arg = PIT_TICK_RATE / arg;
303 kd_mksound(hz: arg, ticks: 0);
304 break;
305
306 case KDMKTONE:
307 if (!perm)
308 return -EPERM;
309 {
310 unsigned int ticks, count;
311
312 /*
313 * Generate the tone for the appropriate number of ticks.
314 * If the time is zero, turn off sound ourselves.
315 */
316 ticks = msecs_to_jiffies(m: (arg >> 16) & 0xffff);
317 count = ticks ? (arg & 0xffff) : 0;
318 if (count)
319 count = PIT_TICK_RATE / count;
320 kd_mksound(hz: count, ticks);
321 break;
322 }
323
324 case KDGKBTYPE:
325 /*
326 * this is naïve.
327 */
328 return put_user(KB_101, (char __user *)arg);
329
330 /*
331 * These cannot be implemented on any machine that implements
332 * ioperm() in user level (such as Alpha PCs) or not at all.
333 *
334 * XXX: you should never use these, just call ioperm directly..
335 */
336#ifdef CONFIG_X86
337 case KDADDIO:
338 case KDDELIO:
339 /*
340 * KDADDIO and KDDELIO may be able to add ports beyond what
341 * we reject here, but to be safe...
342 *
343 * These are locked internally via sys_ioperm
344 */
345 if (arg < GPFIRST || arg > GPLAST)
346 return -EINVAL;
347
348 return ksys_ioperm(from: arg, num: 1, turn_on: (cmd == KDADDIO)) ? -ENXIO : 0;
349
350 case KDENABIO:
351 case KDDISABIO:
352 return ksys_ioperm(GPFIRST, GPNUM,
353 turn_on: (cmd == KDENABIO)) ? -ENXIO : 0;
354#endif
355
356 /* Linux m68k/i386 interface for setting the keyboard delay/repeat rate */
357
358 case KDKBDREP:
359 {
360 struct kbd_repeat kbrep;
361
362 if (!capable(CAP_SYS_TTY_CONFIG))
363 return -EPERM;
364
365 if (copy_from_user(to: &kbrep, from: up, n: sizeof(struct kbd_repeat)))
366 return -EFAULT;
367
368 ret = kbd_rate(rep: &kbrep);
369 if (ret)
370 return ret;
371 if (copy_to_user(to: up, from: &kbrep, n: sizeof(struct kbd_repeat)))
372 return -EFAULT;
373 break;
374 }
375
376 case KDSETMODE: {
377 if (!perm)
378 return -EPERM;
379
380 guard(console_lock)();
381 return vt_kdsetmode(vc, mode: arg);
382 }
383 case KDGETMODE:
384 return put_user(vc->vc_mode, (int __user *)arg);
385
386 case KDMAPDISP:
387 case KDUNMAPDISP:
388 /*
389 * these work like a combination of mmap and KDENABIO.
390 * this could be easily finished.
391 */
392 return -EINVAL;
393
394 case KDSKBMODE:
395 if (!perm)
396 return -EPERM;
397 ret = vt_do_kdskbmode(console, arg);
398 if (ret)
399 return ret;
400 tty_ldisc_flush(tty);
401 break;
402
403 case KDGKBMODE:
404 return put_user(vt_do_kdgkbmode(console), (int __user *)arg);
405
406 /* this could be folded into KDSKBMODE, but for compatibility
407 reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */
408 case KDSKBMETA:
409 return vt_do_kdskbmeta(console, arg);
410
411 case KDGKBMETA:
412 /* FIXME: should review whether this is worth locking */
413 return put_user(vt_do_kdgkbmeta(console), (int __user *)arg);
414
415 case KDGETKEYCODE:
416 case KDSETKEYCODE:
417 if(!capable(CAP_SYS_TTY_CONFIG))
418 perm = 0;
419 return vt_do_kbkeycode_ioctl(cmd, user_kbkc: up, perm);
420
421 case KDGKBENT:
422 case KDSKBENT:
423 return vt_do_kdsk_ioctl(cmd, user_kbe: up, perm, console);
424
425 case KDGKBSENT:
426 case KDSKBSENT:
427 return vt_do_kdgkb_ioctl(cmd, user_kdgkb: up, perm);
428
429 /* Diacritical processing. Handled in keyboard.c as it has
430 to operate on the keyboard locks and structures */
431 case KDGKBDIACR:
432 case KDGKBDIACRUC:
433 case KDSKBDIACR:
434 case KDSKBDIACRUC:
435 return vt_do_diacrit(cmd, up, eperm: perm);
436
437 /* the ioctls below read/set the flags usually shown in the leds */
438 /* don't use them - they will go away without warning */
439 case KDGKBLED:
440 case KDSKBLED:
441 case KDGETLED:
442 case KDSETLED:
443 return vt_do_kdskled(console, cmd, arg, perm);
444
445 /*
446 * A process can indicate its willingness to accept signals
447 * generated by pressing an appropriate key combination.
448 * Thus, one can have a daemon that e.g. spawns a new console
449 * upon a keypress and then changes to it.
450 * See also the kbrequest field of inittab(5).
451 */
452 case KDSIGACCEPT:
453 if (!perm || !capable(CAP_KILL))
454 return -EPERM;
455 if (!valid_signal(sig: arg) || arg < 1 || arg == SIGKILL)
456 return -EINVAL;
457
458 spin_lock_irq(lock: &vt_spawn_con.lock);
459 put_pid(pid: vt_spawn_con.pid);
460 vt_spawn_con.pid = get_pid(pid: task_pid(current));
461 vt_spawn_con.sig = arg;
462 spin_unlock_irq(lock: &vt_spawn_con.lock);
463 break;
464
465 case KDFONTOP: {
466 struct console_font_op op;
467
468 if (copy_from_user(to: &op, from: up, n: sizeof(op)))
469 return -EFAULT;
470 if (!perm && op.op != KD_FONT_OP_GET)
471 return -EPERM;
472 ret = con_font_op(vc, op: &op);
473 if (ret)
474 return ret;
475 if (copy_to_user(to: up, from: &op, n: sizeof(op)))
476 return -EFAULT;
477 break;
478 }
479
480 default:
481 return -ENOIOCTLCMD;
482 }
483
484 return 0;
485}
486
487static inline int do_unimap_ioctl(int cmd, struct unimapdesc __user *user_ud,
488 bool perm, struct vc_data *vc)
489{
490 struct unimapdesc tmp;
491
492 if (copy_from_user(to: &tmp, from: user_ud, n: sizeof tmp))
493 return -EFAULT;
494 switch (cmd) {
495 case PIO_UNIMAP:
496 if (!perm)
497 return -EPERM;
498 return con_set_unimap(vc, ct: tmp.entry_ct, list: tmp.entries);
499 case GIO_UNIMAP:
500 if (!perm && fg_console != vc->vc_num)
501 return -EPERM;
502 return con_get_unimap(vc, ct: tmp.entry_ct, uct: &(user_ud->entry_ct),
503 list: tmp.entries);
504 }
505 return 0;
506}
507
508static int vt_io_ioctl(struct vc_data *vc, unsigned int cmd, void __user *up,
509 bool perm)
510{
511 switch (cmd) {
512 case PIO_CMAP:
513 if (!perm)
514 return -EPERM;
515 return con_set_cmap(cmap: up);
516
517 case GIO_CMAP:
518 return con_get_cmap(cmap: up);
519
520 case PIO_SCRNMAP:
521 if (!perm)
522 return -EPERM;
523 return con_set_trans_old(table: up);
524
525 case GIO_SCRNMAP:
526 return con_get_trans_old(table: up);
527
528 case PIO_UNISCRNMAP:
529 if (!perm)
530 return -EPERM;
531 return con_set_trans_new(table: up);
532
533 case GIO_UNISCRNMAP:
534 return con_get_trans_new(table: up);
535
536 case PIO_UNIMAPCLR:
537 if (!perm)
538 return -EPERM;
539 con_clear_unimap(vc);
540 break;
541
542 case PIO_UNIMAP:
543 case GIO_UNIMAP:
544 return do_unimap_ioctl(cmd, user_ud: up, perm, vc);
545
546 default:
547 return -ENOIOCTLCMD;
548 }
549
550 return 0;
551}
552
553static int vt_reldisp(struct vc_data *vc, unsigned int swtch)
554{
555 int newvt, ret;
556
557 if (vc->vt_mode.mode != VT_PROCESS)
558 return -EINVAL;
559
560 /* Switched-to response */
561 if (vc->vt_newvt < 0) {
562 /* If it's just an ACK, ignore it */
563 return swtch == VT_ACKACQ ? 0 : -EINVAL;
564 }
565
566 /* Switching-from response */
567 if (swtch == 0) {
568 /* Switch disallowed, so forget we were trying to do it. */
569 vc->vt_newvt = -1;
570 return 0;
571 }
572
573 /* The current vt has been released, so complete the switch. */
574 newvt = vc->vt_newvt;
575 vc->vt_newvt = -1;
576 ret = vc_allocate(console: newvt);
577 if (ret)
578 return ret;
579
580 /*
581 * When we actually do the console switch, make sure we are atomic with
582 * respect to other console switches..
583 */
584 complete_change_console(vc: vc_cons[newvt].d);
585
586 return 0;
587}
588
589static int vt_setactivate(struct vt_setactivate __user *sa)
590{
591 struct vt_setactivate vsa;
592 struct vc_data *nvc;
593 int ret;
594
595 if (copy_from_user(to: &vsa, from: sa, n: sizeof(vsa)))
596 return -EFAULT;
597 if (vsa.console == 0 || vsa.console > MAX_NR_CONSOLES)
598 return -ENXIO;
599
600 vsa.console--;
601 vsa.console = array_index_nospec(vsa.console, MAX_NR_CONSOLES);
602 scoped_guard(console_lock) {
603 ret = vc_allocate(console: vsa.console);
604 if (ret)
605 return ret;
606
607 /*
608 * This is safe providing we don't drop the console sem between
609 * vc_allocate and finishing referencing nvc.
610 */
611 nvc = vc_cons[vsa.console].d;
612 nvc->vt_mode = vsa.mode;
613 nvc->vt_mode.frsig = 0;
614 put_pid(pid: nvc->vt_pid);
615 nvc->vt_pid = get_pid(pid: task_pid(current));
616 }
617
618 /* Commence switch and lock */
619 /* Review set_console locks */
620 set_console(vsa.console);
621
622 return 0;
623}
624
625/* deallocate a single console, if possible (leave 0) */
626static int vt_disallocate(unsigned int vc_num)
627{
628 struct vc_data *vc = NULL;
629
630 scoped_guard(console_lock) {
631 if (vt_busy(i: vc_num))
632 return -EBUSY;
633 if (vc_num)
634 vc = vc_deallocate(console: vc_num);
635 }
636
637 if (vc && vc_num >= MIN_NR_CONSOLES)
638 tty_port_put(port: &vc->port);
639
640 return 0;
641}
642
643/* deallocate all unused consoles, but leave 0 */
644static void vt_disallocate_all(void)
645{
646 struct vc_data *vc[MAX_NR_CONSOLES];
647 int i;
648
649 scoped_guard(console_lock)
650 for (i = 1; i < MAX_NR_CONSOLES; i++)
651 if (!vt_busy(i))
652 vc[i] = vc_deallocate(console: i);
653 else
654 vc[i] = NULL;
655
656 for (i = 1; i < MAX_NR_CONSOLES; i++) {
657 if (vc[i] && i >= MIN_NR_CONSOLES)
658 tty_port_put(port: &vc[i]->port);
659 }
660}
661
662static int vt_resizex(struct vc_data *vc, struct vt_consize __user *cs)
663{
664 struct vt_consize v;
665 int i;
666
667 if (copy_from_user(to: &v, from: cs, n: sizeof(struct vt_consize)))
668 return -EFAULT;
669
670 /* FIXME: Should check the copies properly */
671 if (!v.v_vlin)
672 v.v_vlin = vc->vc_scan_lines;
673
674 if (v.v_clin) {
675 int rows = v.v_vlin / v.v_clin;
676 if (v.v_rows != rows) {
677 if (v.v_rows) /* Parameters don't add up */
678 return -EINVAL;
679 v.v_rows = rows;
680 }
681 }
682
683 if (v.v_vcol && v.v_ccol) {
684 int cols = v.v_vcol / v.v_ccol;
685 if (v.v_cols != cols) {
686 if (v.v_cols)
687 return -EINVAL;
688 v.v_cols = cols;
689 }
690 }
691
692 if (v.v_clin > 32)
693 return -EINVAL;
694
695 for (i = 0; i < MAX_NR_CONSOLES; i++) {
696 struct vc_data *vcp;
697
698 if (!vc_cons[i].d)
699 continue;
700 guard(console_lock)();
701 vcp = vc_cons[i].d;
702 if (vcp) {
703 int ret;
704 int save_scan_lines = vcp->vc_scan_lines;
705 int save_cell_height = vcp->vc_cell_height;
706
707 if (v.v_vlin)
708 vcp->vc_scan_lines = v.v_vlin;
709 if (v.v_clin)
710 vcp->vc_cell_height = v.v_clin;
711 ret = __vc_resize(vc: vcp, cols: v.v_cols, lines: v.v_rows, from_user: true);
712 if (ret) {
713 vcp->vc_scan_lines = save_scan_lines;
714 vcp->vc_cell_height = save_cell_height;
715 return ret;
716 }
717 }
718 }
719
720 return 0;
721}
722
723/*
724 * We handle the console-specific ioctl's here. We allow the
725 * capability to modify any console, not just the fg_console.
726 */
727int vt_ioctl(struct tty_struct *tty,
728 unsigned int cmd, unsigned long arg)
729{
730 struct vc_data *vc = tty->driver_data;
731 void __user *up = (void __user *)arg;
732 int i, perm;
733 int ret;
734
735 /*
736 * To have permissions to do most of the vt ioctls, we either have
737 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
738 */
739 perm = 0;
740 if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
741 perm = 1;
742
743 ret = vt_k_ioctl(tty, cmd, arg, perm);
744 if (ret != -ENOIOCTLCMD)
745 return ret;
746
747 ret = vt_io_ioctl(vc, cmd, up, perm);
748 if (ret != -ENOIOCTLCMD)
749 return ret;
750
751 switch (cmd) {
752 case TIOCLINUX:
753 return tioclinux(tty, arg);
754 case VT_SETMODE:
755 {
756 struct vt_mode tmp;
757
758 if (!perm)
759 return -EPERM;
760 if (copy_from_user(to: &tmp, from: up, n: sizeof(struct vt_mode)))
761 return -EFAULT;
762 if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS)
763 return -EINVAL;
764
765 guard(console_lock)();
766 vc->vt_mode = tmp;
767 /* the frsig is ignored, so we set it to 0 */
768 vc->vt_mode.frsig = 0;
769 put_pid(pid: vc->vt_pid);
770 vc->vt_pid = get_pid(pid: task_pid(current));
771 /* no switch is required -- saw@shade.msu.ru */
772 vc->vt_newvt = -1;
773 break;
774 }
775
776 case VT_GETMODE:
777 {
778 struct vt_mode tmp;
779 int rc;
780
781 scoped_guard(console_lock)
782 memcpy(to: &tmp, from: &vc->vt_mode, len: sizeof(struct vt_mode));
783
784 rc = copy_to_user(to: up, from: &tmp, n: sizeof(struct vt_mode));
785 if (rc)
786 return -EFAULT;
787 break;
788 }
789
790 /*
791 * Returns global vt state. Note that VT 0 is always open, since
792 * it's an alias for the current VT, and people can't use it here.
793 * We cannot return state for more than 16 VTs, since v_state is short.
794 */
795 case VT_GETSTATE:
796 {
797 struct vt_stat __user *vtstat = up;
798 unsigned short state, mask;
799
800 if (put_user(fg_console + 1, &vtstat->v_active))
801 return -EFAULT;
802
803 state = 1; /* /dev/tty0 is always open */
804 scoped_guard(console_lock) /* required by vt_in_use() */
805 for (i = 0, mask = 2; i < MAX_NR_CONSOLES && mask; ++i, mask <<= 1)
806 if (vt_in_use(i))
807 state |= mask;
808 return put_user(state, &vtstat->v_state);
809 }
810
811 /*
812 * Returns the first available (non-opened) console.
813 */
814 case VT_OPENQRY:
815 scoped_guard(console_lock) /* required by vt_in_use() */
816 for (i = 0; i < MAX_NR_CONSOLES; ++i)
817 if (!vt_in_use(i))
818 break;
819 i = i < MAX_NR_CONSOLES ? (i+1) : -1;
820 return put_user(i, (int __user *)arg);
821
822 /*
823 * ioctl(fd, VT_ACTIVATE, num) will cause us to switch to vt # num,
824 * with num >= 1 (switches to vt 0, our console, are not allowed, just
825 * to preserve sanity).
826 */
827 case VT_ACTIVATE:
828 if (!perm)
829 return -EPERM;
830 if (arg == 0 || arg > MAX_NR_CONSOLES)
831 return -ENXIO;
832
833 arg--;
834 arg = array_index_nospec(arg, MAX_NR_CONSOLES);
835 scoped_guard(console_lock) {
836 ret = vc_allocate(console: arg);
837 if (ret)
838 return ret;
839 }
840 set_console(arg);
841 break;
842
843 case VT_SETACTIVATE:
844 if (!perm)
845 return -EPERM;
846
847 return vt_setactivate(sa: up);
848
849 /*
850 * wait until the specified VT has been activated
851 */
852 case VT_WAITACTIVE:
853 if (!perm)
854 return -EPERM;
855 if (arg == 0 || arg > MAX_NR_CONSOLES)
856 return -ENXIO;
857 return vt_waitactive(n: arg);
858
859 /*
860 * If a vt is under process control, the kernel will not switch to it
861 * immediately, but postpone the operation until the process calls this
862 * ioctl, allowing the switch to complete.
863 *
864 * According to the X sources this is the behavior:
865 * 0: pending switch-from not OK
866 * 1: pending switch-from OK
867 * 2: completed switch-to OK
868 */
869 case VT_RELDISP:
870 {
871 if (!perm)
872 return -EPERM;
873
874 guard(console_lock)();
875 return vt_reldisp(vc, swtch: arg);
876 }
877
878 /*
879 * Disallocate memory associated to VT (but leave VT1)
880 */
881 case VT_DISALLOCATE:
882 if (arg > MAX_NR_CONSOLES)
883 return -ENXIO;
884
885 if (arg == 0) {
886 vt_disallocate_all();
887 break;
888 }
889
890 arg = array_index_nospec(arg - 1, MAX_NR_CONSOLES);
891 return vt_disallocate(vc_num: arg);
892
893 case VT_RESIZE:
894 {
895 struct vt_sizes __user *vtsizes = up;
896 struct vc_data *vc;
897 ushort ll,cc;
898
899 if (!perm)
900 return -EPERM;
901 if (get_user(ll, &vtsizes->v_rows) ||
902 get_user(cc, &vtsizes->v_cols))
903 return -EFAULT;
904
905 guard(console_lock)();
906 for (i = 0; i < MAX_NR_CONSOLES; i++) {
907 vc = vc_cons[i].d;
908
909 if (vc) {
910 /* FIXME: review v tty lock */
911 ret = __vc_resize(vc: vc_cons[i].d, cols: cc, lines: ll, from_user: true);
912 if (ret)
913 return ret;
914 }
915 }
916 break;
917 }
918
919 case VT_RESIZEX:
920 if (!perm)
921 return -EPERM;
922
923 return vt_resizex(vc, cs: up);
924
925 case VT_LOCKSWITCH:
926 if (!capable(CAP_SYS_TTY_CONFIG))
927 return -EPERM;
928 vt_dont_switch = true;
929 break;
930 case VT_UNLOCKSWITCH:
931 if (!capable(CAP_SYS_TTY_CONFIG))
932 return -EPERM;
933 vt_dont_switch = false;
934 break;
935 case VT_GETHIFONTMASK:
936 return put_user(vc->vc_hi_font_mask,
937 (unsigned short __user *)arg);
938 case VT_WAITEVENT:
939 return vt_event_wait_ioctl(event: (struct vt_event __user *)arg);
940
941 case VT_GETCONSIZECSRPOS:
942 {
943 struct vt_consizecsrpos concsr;
944
945 console_lock();
946 concsr.con_cols = vc->vc_cols;
947 concsr.con_rows = vc->vc_rows;
948 concsr.csr_col = vc->state.x;
949 concsr.csr_row = vc->state.y;
950 console_unlock();
951 if (copy_to_user(to: up, from: &concsr, n: sizeof(concsr)))
952 return -EFAULT;
953 return 0;
954 }
955
956 default:
957 return -ENOIOCTLCMD;
958 }
959
960 return 0;
961}
962
963void reset_vc(struct vc_data *vc)
964{
965 vc->vc_mode = KD_TEXT;
966 vt_reset_unicode(console: vc->vc_num);
967 vc->vt_mode.mode = VT_AUTO;
968 vc->vt_mode.waitv = 0;
969 vc->vt_mode.relsig = 0;
970 vc->vt_mode.acqsig = 0;
971 vc->vt_mode.frsig = 0;
972 put_pid(pid: vc->vt_pid);
973 vc->vt_pid = NULL;
974 vc->vt_newvt = -1;
975 reset_palette(vc);
976}
977
978void vc_SAK(struct work_struct *work)
979{
980 struct vc *vc_con =
981 container_of(work, struct vc, SAK_work);
982 struct vc_data *vc;
983 struct tty_struct *tty;
984
985 guard(console_lock)();
986 vc = vc_con->d;
987 if (!vc)
988 return;
989
990 /* FIXME: review tty ref counting */
991 tty = vc->port.tty;
992 /* SAK should also work in all raw modes and reset them properly. */
993 if (tty)
994 __do_SAK(tty);
995 reset_vc(vc);
996}
997
998#ifdef CONFIG_COMPAT
999
1000struct compat_console_font_op {
1001 compat_uint_t op; /* operation code KD_FONT_OP_* */
1002 compat_uint_t flags; /* KD_FONT_FLAG_* */
1003 compat_uint_t width, height; /* font size */
1004 compat_uint_t charcount;
1005 compat_caddr_t data; /* font data with height fixed to 32 */
1006};
1007
1008static inline int
1009compat_kdfontop_ioctl(struct compat_console_font_op __user *fontop,
1010 int perm, struct console_font_op *op, struct vc_data *vc)
1011{
1012 int i;
1013
1014 if (copy_from_user(to: op, from: fontop, n: sizeof(struct compat_console_font_op)))
1015 return -EFAULT;
1016 if (!perm && op->op != KD_FONT_OP_GET)
1017 return -EPERM;
1018 op->data = compat_ptr(uptr: ((struct compat_console_font_op *)op)->data);
1019 i = con_font_op(vc, op);
1020 if (i)
1021 return i;
1022 ((struct compat_console_font_op *)op)->data = (unsigned long)op->data;
1023 if (copy_to_user(to: fontop, from: op, n: sizeof(struct compat_console_font_op)))
1024 return -EFAULT;
1025 return 0;
1026}
1027
1028struct compat_unimapdesc {
1029 unsigned short entry_ct;
1030 compat_caddr_t entries;
1031};
1032
1033static inline int
1034compat_unimap_ioctl(unsigned int cmd, struct compat_unimapdesc __user *user_ud,
1035 int perm, struct vc_data *vc)
1036{
1037 struct compat_unimapdesc tmp;
1038 struct unipair __user *tmp_entries;
1039
1040 if (copy_from_user(to: &tmp, from: user_ud, n: sizeof tmp))
1041 return -EFAULT;
1042 tmp_entries = compat_ptr(uptr: tmp.entries);
1043 switch (cmd) {
1044 case PIO_UNIMAP:
1045 if (!perm)
1046 return -EPERM;
1047 return con_set_unimap(vc, ct: tmp.entry_ct, list: tmp_entries);
1048 case GIO_UNIMAP:
1049 if (!perm && fg_console != vc->vc_num)
1050 return -EPERM;
1051 return con_get_unimap(vc, ct: tmp.entry_ct, uct: &(user_ud->entry_ct), list: tmp_entries);
1052 }
1053 return 0;
1054}
1055
1056long vt_compat_ioctl(struct tty_struct *tty,
1057 unsigned int cmd, unsigned long arg)
1058{
1059 struct vc_data *vc = tty->driver_data;
1060 struct console_font_op op; /* used in multiple places here */
1061 void __user *up = compat_ptr(uptr: arg);
1062 int perm;
1063
1064 /*
1065 * To have permissions to do most of the vt ioctls, we either have
1066 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
1067 */
1068 perm = 0;
1069 if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
1070 perm = 1;
1071
1072 switch (cmd) {
1073 /*
1074 * these need special handlers for incompatible data structures
1075 */
1076
1077 case KDFONTOP:
1078 return compat_kdfontop_ioctl(fontop: up, perm, op: &op, vc);
1079
1080 case PIO_UNIMAP:
1081 case GIO_UNIMAP:
1082 return compat_unimap_ioctl(cmd, user_ud: up, perm, vc);
1083
1084 /*
1085 * all these treat 'arg' as an integer
1086 */
1087 case KIOCSOUND:
1088 case KDMKTONE:
1089#ifdef CONFIG_X86
1090 case KDADDIO:
1091 case KDDELIO:
1092#endif
1093 case KDSETMODE:
1094 case KDMAPDISP:
1095 case KDUNMAPDISP:
1096 case KDSKBMODE:
1097 case KDSKBMETA:
1098 case KDSKBLED:
1099 case KDSETLED:
1100 case KDSIGACCEPT:
1101 case VT_ACTIVATE:
1102 case VT_WAITACTIVE:
1103 case VT_RELDISP:
1104 case VT_DISALLOCATE:
1105 return vt_ioctl(tty, cmd, arg);
1106
1107 /*
1108 * the rest has a compatible data structure behind arg,
1109 * but we have to convert it to a proper 64 bit pointer.
1110 */
1111 default:
1112 return vt_ioctl(tty, cmd, arg: (unsigned long)up);
1113 }
1114}
1115
1116
1117#endif /* CONFIG_COMPAT */
1118
1119
1120/*
1121 * Performs the back end of a vt switch. Called under the console
1122 * semaphore.
1123 */
1124static void complete_change_console(struct vc_data *vc)
1125{
1126 unsigned char old_vc_mode;
1127 int old = fg_console;
1128
1129 last_console = fg_console;
1130
1131 /*
1132 * If we're switching, we could be going from KD_GRAPHICS to
1133 * KD_TEXT mode or vice versa, which means we need to blank or
1134 * unblank the screen later.
1135 */
1136 old_vc_mode = vc_cons[fg_console].d->vc_mode;
1137 switch_screen(vc);
1138
1139 /*
1140 * This can't appear below a successful kill_pid(). If it did,
1141 * then the *blank_screen operation could occur while X, having
1142 * received acqsig, is waking up on another processor. This
1143 * condition can lead to overlapping accesses to the VGA range
1144 * and the framebuffer (causing system lockups).
1145 *
1146 * To account for this we duplicate this code below only if the
1147 * controlling process is gone and we've called reset_vc.
1148 */
1149 if (old_vc_mode != vc->vc_mode) {
1150 if (vc->vc_mode == KD_TEXT)
1151 do_unblank_screen(leaving_gfx: 1);
1152 else
1153 do_blank_screen(entering_gfx: 1);
1154 }
1155
1156 /*
1157 * If this new console is under process control, send it a signal
1158 * telling it that it has acquired. Also check if it has died and
1159 * clean up (similar to logic employed in change_console())
1160 */
1161 if (vc->vt_mode.mode == VT_PROCESS) {
1162 /*
1163 * Send the signal as privileged - kill_pid() will
1164 * tell us if the process has gone or something else
1165 * is awry
1166 */
1167 if (kill_pid(pid: vc->vt_pid, sig: vc->vt_mode.acqsig, priv: 1) != 0) {
1168 /*
1169 * The controlling process has died, so we revert back to
1170 * normal operation. In this case, we'll also change back
1171 * to KD_TEXT mode. I'm not sure if this is strictly correct
1172 * but it saves the agony when the X server dies and the screen
1173 * remains blanked due to KD_GRAPHICS! It would be nice to do
1174 * this outside of VT_PROCESS but there is no single process
1175 * to account for and tracking tty count may be undesirable.
1176 */
1177 reset_vc(vc);
1178
1179 if (old_vc_mode != vc->vc_mode) {
1180 if (vc->vc_mode == KD_TEXT)
1181 do_unblank_screen(leaving_gfx: 1);
1182 else
1183 do_blank_screen(entering_gfx: 1);
1184 }
1185 }
1186 }
1187
1188 /*
1189 * Wake anyone waiting for their VT to activate
1190 */
1191 vt_event_post(VT_EVENT_SWITCH, old, new: vc->vc_num);
1192 return;
1193}
1194
1195/*
1196 * Performs the front-end of a vt switch
1197 */
1198void change_console(struct vc_data *new_vc)
1199{
1200 struct vc_data *vc;
1201
1202 if (!new_vc || new_vc->vc_num == fg_console || vt_dont_switch)
1203 return;
1204
1205 /*
1206 * If this vt is in process mode, then we need to handshake with
1207 * that process before switching. Essentially, we store where that
1208 * vt wants to switch to and wait for it to tell us when it's done
1209 * (via VT_RELDISP ioctl).
1210 *
1211 * We also check to see if the controlling process still exists.
1212 * If it doesn't, we reset this vt to auto mode and continue.
1213 * This is a cheap way to track process control. The worst thing
1214 * that can happen is: we send a signal to a process, it dies, and
1215 * the switch gets "lost" waiting for a response; hopefully, the
1216 * user will try again, we'll detect the process is gone (unless
1217 * the user waits just the right amount of time :-) and revert the
1218 * vt to auto control.
1219 */
1220 vc = vc_cons[fg_console].d;
1221 if (vc->vt_mode.mode == VT_PROCESS) {
1222 /*
1223 * Send the signal as privileged - kill_pid() will
1224 * tell us if the process has gone or something else
1225 * is awry.
1226 *
1227 * We need to set vt_newvt *before* sending the signal or we
1228 * have a race.
1229 */
1230 vc->vt_newvt = new_vc->vc_num;
1231 if (kill_pid(pid: vc->vt_pid, sig: vc->vt_mode.relsig, priv: 1) == 0) {
1232 /*
1233 * It worked. Mark the vt to switch to and
1234 * return. The process needs to send us a
1235 * VT_RELDISP ioctl to complete the switch.
1236 */
1237 return;
1238 }
1239
1240 /*
1241 * The controlling process has died, so we revert back to
1242 * normal operation. In this case, we'll also change back
1243 * to KD_TEXT mode. I'm not sure if this is strictly correct
1244 * but it saves the agony when the X server dies and the screen
1245 * remains blanked due to KD_GRAPHICS! It would be nice to do
1246 * this outside of VT_PROCESS but there is no single process
1247 * to account for and tracking tty count may be undesirable.
1248 */
1249 reset_vc(vc);
1250
1251 /*
1252 * Fall through to normal (VT_AUTO) handling of the switch...
1253 */
1254 }
1255
1256 /*
1257 * Ignore all switches in KD_GRAPHICS+VT_AUTO mode
1258 */
1259 if (vc->vc_mode == KD_GRAPHICS)
1260 return;
1261
1262 complete_change_console(vc: new_vc);
1263}
1264
1265/* Perform a kernel triggered VT switch for suspend/resume */
1266
1267static int disable_vt_switch;
1268
1269int vt_move_to_console(unsigned int vt, int alloc)
1270{
1271 int prev;
1272
1273 scoped_guard(console_lock) {
1274 /* Graphics mode - up to X */
1275 if (disable_vt_switch)
1276 return 0;
1277
1278 prev = fg_console;
1279
1280 if (alloc && vc_allocate(console: vt)) {
1281 /*
1282 * We can't have a free VC for now. Too bad, we don't want to mess the
1283 * screen for now.
1284 */
1285 return -ENOSPC;
1286 }
1287
1288 if (set_console(vt)) {
1289 /*
1290 * We're unable to switch to the SUSPEND_CONSOLE. Let the calling function
1291 * know so it can decide what to do.
1292 */
1293 return -EIO;
1294 }
1295 }
1296 if (vt_waitactive(n: vt + 1)) {
1297 pr_debug("Suspend: Can't switch VCs.");
1298 return -EINTR;
1299 }
1300 return prev;
1301}
1302
1303/*
1304 * Normally during a suspend, we allocate a new console and switch to it.
1305 * When we resume, we switch back to the original console. This switch
1306 * can be slow, so on systems where the framebuffer can handle restoration
1307 * of video registers anyways, there's little point in doing the console
1308 * switch. This function allows you to disable it by passing it '0'.
1309 */
1310void pm_set_vt_switch(int do_switch)
1311{
1312 guard(console_lock)();
1313 disable_vt_switch = !do_switch;
1314}
1315EXPORT_SYMBOL(pm_set_vt_switch);
1316