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 
42 bool vt_dont_switch;
43 
vt_in_use(unsigned int i)44 static 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(&vc->port.kref) > 1;
55 }
56 
vt_busy(int i)57 static 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_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 
86 static void complete_change_console(struct vc_data *vc);
87 
88 /*
89  *	User space VT_EVENT handlers
90  */
91 
92 struct vt_event_wait {
93 	struct list_head list;
94 	struct vt_event event;
95 	int done;
96 };
97 
98 static LIST_HEAD(vt_events);
99 static DEFINE_SPINLOCK(vt_event_lock);
100 static 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 
vt_event_post(unsigned int event,unsigned int old,unsigned int new)111 void 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(&vt_event_lock, flags);
134 	if (wake)
135 		wake_up_interruptible(&vt_event_waitqueue);
136 }
137 
__vt_event_queue(struct vt_event_wait * vw)138 static void __vt_event_queue(struct vt_event_wait *vw)
139 {
140 	unsigned long flags;
141 	/* Prepare the event */
142 	INIT_LIST_HEAD(&vw->list);
143 	vw->done = 0;
144 	/* Queue our event */
145 	spin_lock_irqsave(&vt_event_lock, flags);
146 	list_add(&vw->list, &vt_events);
147 	spin_unlock_irqrestore(&vt_event_lock, flags);
148 }
149 
__vt_event_wait(struct vt_event_wait * vw)150 static 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 
__vt_event_dequeue(struct vt_event_wait * vw)156 static 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(&vw->list);
163 	spin_unlock_irqrestore(&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 
vt_event_wait(struct vt_event_wait * vw)175 static 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 
vt_event_wait_ioctl(struct vt_event __user * event)189 static int vt_event_wait_ioctl(struct vt_event __user *event)
190 {
191 	struct vt_event_wait vw;
192 
193 	if (copy_from_user(&vw.event, event, 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);
200 	/* If it occurred report it */
201 	if (vw.done) {
202 		if (copy_to_user(event, &vw.event, 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 
vt_waitactive(int n)217 int 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);
223 		if (n == fg_console + 1) {
224 			__vt_event_dequeue(&vw);
225 			break;
226 		}
227 		__vt_event_wait(&vw);
228 		__vt_event_dequeue(&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  */
vt_kdsetmode(struct vc_data * vc,unsigned long mode)252 static 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(1);
277 	else
278 		do_blank_screen(1);
279 
280 	return 0;
281 }
282 
vt_k_ioctl(struct tty_struct * tty,unsigned int cmd,unsigned long arg,bool perm)283 static 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(arg, 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((arg >> 16) & 0xffff);
317 		count = ticks ? (arg & 0xffff) : 0;
318 		if (count)
319 			count = PIT_TICK_RATE / count;
320 		kd_mksound(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(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;
349 
350 	case KDENABIO:
351 	case KDDISABIO:
352 		return ksys_ioperm(GPFIRST, GPNUM,
353 				  (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(&kbrep, up, sizeof(struct kbd_repeat)))
366 			return -EFAULT;
367 
368 		ret = kbd_rate(&kbrep);
369 		if (ret)
370 			return ret;
371 		if (copy_to_user(up, &kbrep, sizeof(struct kbd_repeat)))
372 			return -EFAULT;
373 		break;
374 	}
375 
376 	case KDSETMODE:
377 		if (!perm)
378 			return -EPERM;
379 
380 		console_lock();
381 		ret = vt_kdsetmode(vc, arg);
382 		console_unlock();
383 		return ret;
384 
385 	case KDGETMODE:
386 		return put_user(vc->vc_mode, (int __user *)arg);
387 
388 	case KDMAPDISP:
389 	case KDUNMAPDISP:
390 		/*
391 		 * these work like a combination of mmap and KDENABIO.
392 		 * this could be easily finished.
393 		 */
394 		return -EINVAL;
395 
396 	case KDSKBMODE:
397 		if (!perm)
398 			return -EPERM;
399 		ret = vt_do_kdskbmode(console, arg);
400 		if (ret)
401 			return ret;
402 		tty_ldisc_flush(tty);
403 		break;
404 
405 	case KDGKBMODE:
406 		return put_user(vt_do_kdgkbmode(console), (int __user *)arg);
407 
408 	/* this could be folded into KDSKBMODE, but for compatibility
409 	   reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */
410 	case KDSKBMETA:
411 		return vt_do_kdskbmeta(console, arg);
412 
413 	case KDGKBMETA:
414 		/* FIXME: should review whether this is worth locking */
415 		return put_user(vt_do_kdgkbmeta(console), (int __user *)arg);
416 
417 	case KDGETKEYCODE:
418 	case KDSETKEYCODE:
419 		if(!capable(CAP_SYS_TTY_CONFIG))
420 			perm = 0;
421 		return vt_do_kbkeycode_ioctl(cmd, up, perm);
422 
423 	case KDGKBENT:
424 	case KDSKBENT:
425 		return vt_do_kdsk_ioctl(cmd, up, perm, console);
426 
427 	case KDGKBSENT:
428 	case KDSKBSENT:
429 		return vt_do_kdgkb_ioctl(cmd, up, perm);
430 
431 	/* Diacritical processing. Handled in keyboard.c as it has
432 	   to operate on the keyboard locks and structures */
433 	case KDGKBDIACR:
434 	case KDGKBDIACRUC:
435 	case KDSKBDIACR:
436 	case KDSKBDIACRUC:
437 		return vt_do_diacrit(cmd, up, perm);
438 
439 	/* the ioctls below read/set the flags usually shown in the leds */
440 	/* don't use them - they will go away without warning */
441 	case KDGKBLED:
442 	case KDSKBLED:
443 	case KDGETLED:
444 	case KDSETLED:
445 		return vt_do_kdskled(console, cmd, arg, perm);
446 
447 	/*
448 	 * A process can indicate its willingness to accept signals
449 	 * generated by pressing an appropriate key combination.
450 	 * Thus, one can have a daemon that e.g. spawns a new console
451 	 * upon a keypress and then changes to it.
452 	 * See also the kbrequest field of inittab(5).
453 	 */
454 	case KDSIGACCEPT:
455 		if (!perm || !capable(CAP_KILL))
456 			return -EPERM;
457 		if (!valid_signal(arg) || arg < 1 || arg == SIGKILL)
458 			return -EINVAL;
459 
460 		spin_lock_irq(&vt_spawn_con.lock);
461 		put_pid(vt_spawn_con.pid);
462 		vt_spawn_con.pid = get_pid(task_pid(current));
463 		vt_spawn_con.sig = arg;
464 		spin_unlock_irq(&vt_spawn_con.lock);
465 		break;
466 
467 	case KDFONTOP: {
468 		struct console_font_op op;
469 
470 		if (copy_from_user(&op, up, sizeof(op)))
471 			return -EFAULT;
472 		if (!perm && op.op != KD_FONT_OP_GET)
473 			return -EPERM;
474 		ret = con_font_op(vc, &op);
475 		if (ret)
476 			return ret;
477 		if (copy_to_user(up, &op, sizeof(op)))
478 			return -EFAULT;
479 		break;
480 	}
481 
482 	default:
483 		return -ENOIOCTLCMD;
484 	}
485 
486 	return 0;
487 }
488 
do_unimap_ioctl(int cmd,struct unimapdesc __user * user_ud,bool perm,struct vc_data * vc)489 static inline int do_unimap_ioctl(int cmd, struct unimapdesc __user *user_ud,
490 		bool perm, struct vc_data *vc)
491 {
492 	struct unimapdesc tmp;
493 
494 	if (copy_from_user(&tmp, user_ud, sizeof tmp))
495 		return -EFAULT;
496 	switch (cmd) {
497 	case PIO_UNIMAP:
498 		if (!perm)
499 			return -EPERM;
500 		return con_set_unimap(vc, tmp.entry_ct, tmp.entries);
501 	case GIO_UNIMAP:
502 		if (!perm && fg_console != vc->vc_num)
503 			return -EPERM;
504 		return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct),
505 				tmp.entries);
506 	}
507 	return 0;
508 }
509 
vt_io_ioctl(struct vc_data * vc,unsigned int cmd,void __user * up,bool perm)510 static int vt_io_ioctl(struct vc_data *vc, unsigned int cmd, void __user *up,
511 		bool perm)
512 {
513 	switch (cmd) {
514 	case PIO_CMAP:
515 		if (!perm)
516 			return -EPERM;
517 		return con_set_cmap(up);
518 
519 	case GIO_CMAP:
520 		return con_get_cmap(up);
521 
522 	case PIO_SCRNMAP:
523 		if (!perm)
524 			return -EPERM;
525 		return con_set_trans_old(up);
526 
527 	case GIO_SCRNMAP:
528 		return con_get_trans_old(up);
529 
530 	case PIO_UNISCRNMAP:
531 		if (!perm)
532 			return -EPERM;
533 		return con_set_trans_new(up);
534 
535 	case GIO_UNISCRNMAP:
536 		return con_get_trans_new(up);
537 
538 	case PIO_UNIMAPCLR:
539 		if (!perm)
540 			return -EPERM;
541 		con_clear_unimap(vc);
542 		break;
543 
544 	case PIO_UNIMAP:
545 	case GIO_UNIMAP:
546 		return do_unimap_ioctl(cmd, up, perm, vc);
547 
548 	default:
549 		return -ENOIOCTLCMD;
550 	}
551 
552 	return 0;
553 }
554 
vt_reldisp(struct vc_data * vc,unsigned int swtch)555 static int vt_reldisp(struct vc_data *vc, unsigned int swtch)
556 {
557 	int newvt, ret;
558 
559 	if (vc->vt_mode.mode != VT_PROCESS)
560 		return -EINVAL;
561 
562 	/* Switched-to response */
563 	if (vc->vt_newvt < 0) {
564 		 /* If it's just an ACK, ignore it */
565 		return swtch == VT_ACKACQ ? 0 : -EINVAL;
566 	}
567 
568 	/* Switching-from response */
569 	if (swtch == 0) {
570 		/* Switch disallowed, so forget we were trying to do it. */
571 		vc->vt_newvt = -1;
572 		return 0;
573 	}
574 
575 	/* The current vt has been released, so complete the switch. */
576 	newvt = vc->vt_newvt;
577 	vc->vt_newvt = -1;
578 	ret = vc_allocate(newvt);
579 	if (ret)
580 		return ret;
581 
582 	/*
583 	 * When we actually do the console switch, make sure we are atomic with
584 	 * respect to other console switches..
585 	 */
586 	complete_change_console(vc_cons[newvt].d);
587 
588 	return 0;
589 }
590 
vt_setactivate(struct vt_setactivate __user * sa)591 static int vt_setactivate(struct vt_setactivate __user *sa)
592 {
593 	struct vt_setactivate vsa;
594 	struct vc_data *nvc;
595 	int ret;
596 
597 	if (copy_from_user(&vsa, sa, sizeof(vsa)))
598 		return -EFAULT;
599 	if (vsa.console == 0 || vsa.console > MAX_NR_CONSOLES)
600 		return -ENXIO;
601 
602 	vsa.console--;
603 	vsa.console = array_index_nospec(vsa.console, MAX_NR_CONSOLES);
604 	console_lock();
605 	ret = vc_allocate(vsa.console);
606 	if (ret) {
607 		console_unlock();
608 		return ret;
609 	}
610 
611 	/*
612 	 * This is safe providing we don't drop the console sem between
613 	 * vc_allocate and finishing referencing nvc.
614 	 */
615 	nvc = vc_cons[vsa.console].d;
616 	nvc->vt_mode = vsa.mode;
617 	nvc->vt_mode.frsig = 0;
618 	put_pid(nvc->vt_pid);
619 	nvc->vt_pid = get_pid(task_pid(current));
620 	console_unlock();
621 
622 	/* Commence switch and lock */
623 	/* Review set_console locks */
624 	set_console(vsa.console);
625 
626 	return 0;
627 }
628 
629 /* deallocate a single console, if possible (leave 0) */
vt_disallocate(unsigned int vc_num)630 static int vt_disallocate(unsigned int vc_num)
631 {
632 	struct vc_data *vc = NULL;
633 	int ret = 0;
634 
635 	console_lock();
636 	if (vt_busy(vc_num))
637 		ret = -EBUSY;
638 	else if (vc_num)
639 		vc = vc_deallocate(vc_num);
640 	console_unlock();
641 
642 	if (vc && vc_num >= MIN_NR_CONSOLES)
643 		tty_port_put(&vc->port);
644 
645 	return ret;
646 }
647 
648 /* deallocate all unused consoles, but leave 0 */
vt_disallocate_all(void)649 static void vt_disallocate_all(void)
650 {
651 	struct vc_data *vc[MAX_NR_CONSOLES];
652 	int i;
653 
654 	console_lock();
655 	for (i = 1; i < MAX_NR_CONSOLES; i++)
656 		if (!vt_busy(i))
657 			vc[i] = vc_deallocate(i);
658 		else
659 			vc[i] = NULL;
660 	console_unlock();
661 
662 	for (i = 1; i < MAX_NR_CONSOLES; i++) {
663 		if (vc[i] && i >= MIN_NR_CONSOLES)
664 			tty_port_put(&vc[i]->port);
665 	}
666 }
667 
vt_resizex(struct vc_data * vc,struct vt_consize __user * cs)668 static int vt_resizex(struct vc_data *vc, struct vt_consize __user *cs)
669 {
670 	struct vt_consize v;
671 	int i;
672 
673 	if (copy_from_user(&v, cs, sizeof(struct vt_consize)))
674 		return -EFAULT;
675 
676 	/* FIXME: Should check the copies properly */
677 	if (!v.v_vlin)
678 		v.v_vlin = vc->vc_scan_lines;
679 
680 	if (v.v_clin) {
681 		int rows = v.v_vlin / v.v_clin;
682 		if (v.v_rows != rows) {
683 			if (v.v_rows) /* Parameters don't add up */
684 				return -EINVAL;
685 			v.v_rows = rows;
686 		}
687 	}
688 
689 	if (v.v_vcol && v.v_ccol) {
690 		int cols = v.v_vcol / v.v_ccol;
691 		if (v.v_cols != cols) {
692 			if (v.v_cols)
693 				return -EINVAL;
694 			v.v_cols = cols;
695 		}
696 	}
697 
698 	if (v.v_clin > 32)
699 		return -EINVAL;
700 
701 	for (i = 0; i < MAX_NR_CONSOLES; i++) {
702 		struct vc_data *vcp;
703 
704 		if (!vc_cons[i].d)
705 			continue;
706 		console_lock();
707 		vcp = vc_cons[i].d;
708 		if (vcp) {
709 			int ret;
710 			int save_scan_lines = vcp->vc_scan_lines;
711 			int save_cell_height = vcp->vc_cell_height;
712 
713 			if (v.v_vlin)
714 				vcp->vc_scan_lines = v.v_vlin;
715 			if (v.v_clin)
716 				vcp->vc_cell_height = v.v_clin;
717 			vcp->vc_resize_user = 1;
718 			ret = vc_resize(vcp, v.v_cols, v.v_rows);
719 			if (ret) {
720 				vcp->vc_scan_lines = save_scan_lines;
721 				vcp->vc_cell_height = save_cell_height;
722 				console_unlock();
723 				return ret;
724 			}
725 		}
726 		console_unlock();
727 	}
728 
729 	return 0;
730 }
731 
732 /*
733  * We handle the console-specific ioctl's here.  We allow the
734  * capability to modify any console, not just the fg_console.
735  */
vt_ioctl(struct tty_struct * tty,unsigned int cmd,unsigned long arg)736 int vt_ioctl(struct tty_struct *tty,
737 	     unsigned int cmd, unsigned long arg)
738 {
739 	struct vc_data *vc = tty->driver_data;
740 	void __user *up = (void __user *)arg;
741 	int i, perm;
742 	int ret;
743 
744 	/*
745 	 * To have permissions to do most of the vt ioctls, we either have
746 	 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
747 	 */
748 	perm = 0;
749 	if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
750 		perm = 1;
751 
752 	ret = vt_k_ioctl(tty, cmd, arg, perm);
753 	if (ret != -ENOIOCTLCMD)
754 		return ret;
755 
756 	ret = vt_io_ioctl(vc, cmd, up, perm);
757 	if (ret != -ENOIOCTLCMD)
758 		return ret;
759 
760 	switch (cmd) {
761 	case TIOCLINUX:
762 		return tioclinux(tty, arg);
763 	case VT_SETMODE:
764 	{
765 		struct vt_mode tmp;
766 
767 		if (!perm)
768 			return -EPERM;
769 		if (copy_from_user(&tmp, up, sizeof(struct vt_mode)))
770 			return -EFAULT;
771 		if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS)
772 			return -EINVAL;
773 
774 		console_lock();
775 		vc->vt_mode = tmp;
776 		/* the frsig is ignored, so we set it to 0 */
777 		vc->vt_mode.frsig = 0;
778 		put_pid(vc->vt_pid);
779 		vc->vt_pid = get_pid(task_pid(current));
780 		/* no switch is required -- saw@shade.msu.ru */
781 		vc->vt_newvt = -1;
782 		console_unlock();
783 		break;
784 	}
785 
786 	case VT_GETMODE:
787 	{
788 		struct vt_mode tmp;
789 		int rc;
790 
791 		console_lock();
792 		memcpy(&tmp, &vc->vt_mode, sizeof(struct vt_mode));
793 		console_unlock();
794 
795 		rc = copy_to_user(up, &tmp, sizeof(struct vt_mode));
796 		if (rc)
797 			return -EFAULT;
798 		break;
799 	}
800 
801 	/*
802 	 * Returns global vt state. Note that VT 0 is always open, since
803 	 * it's an alias for the current VT, and people can't use it here.
804 	 * We cannot return state for more than 16 VTs, since v_state is short.
805 	 */
806 	case VT_GETSTATE:
807 	{
808 		struct vt_stat __user *vtstat = up;
809 		unsigned short state, mask;
810 
811 		if (put_user(fg_console + 1, &vtstat->v_active))
812 			return -EFAULT;
813 
814 		state = 1;	/* /dev/tty0 is always open */
815 		console_lock(); /* required by vt_in_use() */
816 		for (i = 0, mask = 2; i < MAX_NR_CONSOLES && mask;
817 				++i, mask <<= 1)
818 			if (vt_in_use(i))
819 				state |= mask;
820 		console_unlock();
821 		return put_user(state, &vtstat->v_state);
822 	}
823 
824 	/*
825 	 * Returns the first available (non-opened) console.
826 	 */
827 	case VT_OPENQRY:
828 		console_lock(); /* required by vt_in_use() */
829 		for (i = 0; i < MAX_NR_CONSOLES; ++i)
830 			if (!vt_in_use(i))
831 				break;
832 		console_unlock();
833 		i = i < MAX_NR_CONSOLES ? (i+1) : -1;
834 		return put_user(i, (int __user *)arg);
835 
836 	/*
837 	 * ioctl(fd, VT_ACTIVATE, num) will cause us to switch to vt # num,
838 	 * with num >= 1 (switches to vt 0, our console, are not allowed, just
839 	 * to preserve sanity).
840 	 */
841 	case VT_ACTIVATE:
842 		if (!perm)
843 			return -EPERM;
844 		if (arg == 0 || arg > MAX_NR_CONSOLES)
845 			return -ENXIO;
846 
847 		arg--;
848 		arg = array_index_nospec(arg, MAX_NR_CONSOLES);
849 		console_lock();
850 		ret = vc_allocate(arg);
851 		console_unlock();
852 		if (ret)
853 			return ret;
854 		set_console(arg);
855 		break;
856 
857 	case VT_SETACTIVATE:
858 		if (!perm)
859 			return -EPERM;
860 
861 		return vt_setactivate(up);
862 
863 	/*
864 	 * wait until the specified VT has been activated
865 	 */
866 	case VT_WAITACTIVE:
867 		if (!perm)
868 			return -EPERM;
869 		if (arg == 0 || arg > MAX_NR_CONSOLES)
870 			return -ENXIO;
871 		return vt_waitactive(arg);
872 
873 	/*
874 	 * If a vt is under process control, the kernel will not switch to it
875 	 * immediately, but postpone the operation until the process calls this
876 	 * ioctl, allowing the switch to complete.
877 	 *
878 	 * According to the X sources this is the behavior:
879 	 *	0:	pending switch-from not OK
880 	 *	1:	pending switch-from OK
881 	 *	2:	completed switch-to OK
882 	 */
883 	case VT_RELDISP:
884 		if (!perm)
885 			return -EPERM;
886 
887 		console_lock();
888 		ret = vt_reldisp(vc, arg);
889 		console_unlock();
890 
891 		return ret;
892 
893 
894 	 /*
895 	  * Disallocate memory associated to VT (but leave VT1)
896 	  */
897 	 case VT_DISALLOCATE:
898 		if (arg > MAX_NR_CONSOLES)
899 			return -ENXIO;
900 
901 		if (arg == 0) {
902 			vt_disallocate_all();
903 			break;
904 		}
905 
906 		arg = array_index_nospec(arg - 1, MAX_NR_CONSOLES);
907 		return vt_disallocate(arg);
908 
909 	case VT_RESIZE:
910 	{
911 		struct vt_sizes __user *vtsizes = up;
912 		struct vc_data *vc;
913 		ushort ll,cc;
914 
915 		if (!perm)
916 			return -EPERM;
917 		if (get_user(ll, &vtsizes->v_rows) ||
918 		    get_user(cc, &vtsizes->v_cols))
919 			return -EFAULT;
920 
921 		console_lock();
922 		for (i = 0; i < MAX_NR_CONSOLES; i++) {
923 			vc = vc_cons[i].d;
924 
925 			if (vc) {
926 				vc->vc_resize_user = 1;
927 				/* FIXME: review v tty lock */
928 				vc_resize(vc_cons[i].d, cc, ll);
929 			}
930 		}
931 		console_unlock();
932 		break;
933 	}
934 
935 	case VT_RESIZEX:
936 		if (!perm)
937 			return -EPERM;
938 
939 		return vt_resizex(vc, up);
940 
941 	case VT_LOCKSWITCH:
942 		if (!capable(CAP_SYS_TTY_CONFIG))
943 			return -EPERM;
944 		vt_dont_switch = true;
945 		break;
946 	case VT_UNLOCKSWITCH:
947 		if (!capable(CAP_SYS_TTY_CONFIG))
948 			return -EPERM;
949 		vt_dont_switch = false;
950 		break;
951 	case VT_GETHIFONTMASK:
952 		return put_user(vc->vc_hi_font_mask,
953 					(unsigned short __user *)arg);
954 	case VT_WAITEVENT:
955 		return vt_event_wait_ioctl((struct vt_event __user *)arg);
956 	default:
957 		return -ENOIOCTLCMD;
958 	}
959 
960 	return 0;
961 }
962 
reset_vc(struct vc_data * vc)963 void reset_vc(struct vc_data *vc)
964 {
965 	vc->vc_mode = KD_TEXT;
966 	vt_reset_unicode(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(vc->vt_pid);
973 	vc->vt_pid = NULL;
974 	vc->vt_newvt = -1;
975 	reset_palette(vc);
976 }
977 
vc_SAK(struct work_struct * work)978 void 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 	console_lock();
986 	vc = vc_con->d;
987 	if (vc) {
988 		/* FIXME: review tty ref counting */
989 		tty = vc->port.tty;
990 		/*
991 		 * SAK should also work in all raw modes and reset
992 		 * them properly.
993 		 */
994 		if (tty)
995 			__do_SAK(tty);
996 		reset_vc(vc);
997 	}
998 	console_unlock();
999 }
1000 
1001 #ifdef CONFIG_COMPAT
1002 
1003 struct compat_console_font_op {
1004 	compat_uint_t op;        /* operation code KD_FONT_OP_* */
1005 	compat_uint_t flags;     /* KD_FONT_FLAG_* */
1006 	compat_uint_t width, height;     /* font size */
1007 	compat_uint_t charcount;
1008 	compat_caddr_t data;    /* font data with height fixed to 32 */
1009 };
1010 
1011 static inline int
compat_kdfontop_ioctl(struct compat_console_font_op __user * fontop,int perm,struct console_font_op * op,struct vc_data * vc)1012 compat_kdfontop_ioctl(struct compat_console_font_op __user *fontop,
1013 			 int perm, struct console_font_op *op, struct vc_data *vc)
1014 {
1015 	int i;
1016 
1017 	if (copy_from_user(op, fontop, sizeof(struct compat_console_font_op)))
1018 		return -EFAULT;
1019 	if (!perm && op->op != KD_FONT_OP_GET)
1020 		return -EPERM;
1021 	op->data = compat_ptr(((struct compat_console_font_op *)op)->data);
1022 	i = con_font_op(vc, op);
1023 	if (i)
1024 		return i;
1025 	((struct compat_console_font_op *)op)->data = (unsigned long)op->data;
1026 	if (copy_to_user(fontop, op, sizeof(struct compat_console_font_op)))
1027 		return -EFAULT;
1028 	return 0;
1029 }
1030 
1031 struct compat_unimapdesc {
1032 	unsigned short entry_ct;
1033 	compat_caddr_t entries;
1034 };
1035 
1036 static inline int
compat_unimap_ioctl(unsigned int cmd,struct compat_unimapdesc __user * user_ud,int perm,struct vc_data * vc)1037 compat_unimap_ioctl(unsigned int cmd, struct compat_unimapdesc __user *user_ud,
1038 			 int perm, struct vc_data *vc)
1039 {
1040 	struct compat_unimapdesc tmp;
1041 	struct unipair __user *tmp_entries;
1042 
1043 	if (copy_from_user(&tmp, user_ud, sizeof tmp))
1044 		return -EFAULT;
1045 	tmp_entries = compat_ptr(tmp.entries);
1046 	switch (cmd) {
1047 	case PIO_UNIMAP:
1048 		if (!perm)
1049 			return -EPERM;
1050 		return con_set_unimap(vc, tmp.entry_ct, tmp_entries);
1051 	case GIO_UNIMAP:
1052 		if (!perm && fg_console != vc->vc_num)
1053 			return -EPERM;
1054 		return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), tmp_entries);
1055 	}
1056 	return 0;
1057 }
1058 
vt_compat_ioctl(struct tty_struct * tty,unsigned int cmd,unsigned long arg)1059 long vt_compat_ioctl(struct tty_struct *tty,
1060 	     unsigned int cmd, unsigned long arg)
1061 {
1062 	struct vc_data *vc = tty->driver_data;
1063 	struct console_font_op op;	/* used in multiple places here */
1064 	void __user *up = compat_ptr(arg);
1065 	int perm;
1066 
1067 	/*
1068 	 * To have permissions to do most of the vt ioctls, we either have
1069 	 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
1070 	 */
1071 	perm = 0;
1072 	if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
1073 		perm = 1;
1074 
1075 	switch (cmd) {
1076 	/*
1077 	 * these need special handlers for incompatible data structures
1078 	 */
1079 
1080 	case KDFONTOP:
1081 		return compat_kdfontop_ioctl(up, perm, &op, vc);
1082 
1083 	case PIO_UNIMAP:
1084 	case GIO_UNIMAP:
1085 		return compat_unimap_ioctl(cmd, up, perm, vc);
1086 
1087 	/*
1088 	 * all these treat 'arg' as an integer
1089 	 */
1090 	case KIOCSOUND:
1091 	case KDMKTONE:
1092 #ifdef CONFIG_X86
1093 	case KDADDIO:
1094 	case KDDELIO:
1095 #endif
1096 	case KDSETMODE:
1097 	case KDMAPDISP:
1098 	case KDUNMAPDISP:
1099 	case KDSKBMODE:
1100 	case KDSKBMETA:
1101 	case KDSKBLED:
1102 	case KDSETLED:
1103 	case KDSIGACCEPT:
1104 	case VT_ACTIVATE:
1105 	case VT_WAITACTIVE:
1106 	case VT_RELDISP:
1107 	case VT_DISALLOCATE:
1108 	case VT_RESIZE:
1109 	case VT_RESIZEX:
1110 		return vt_ioctl(tty, cmd, arg);
1111 
1112 	/*
1113 	 * the rest has a compatible data structure behind arg,
1114 	 * but we have to convert it to a proper 64 bit pointer.
1115 	 */
1116 	default:
1117 		return vt_ioctl(tty, cmd, (unsigned long)up);
1118 	}
1119 }
1120 
1121 
1122 #endif /* CONFIG_COMPAT */
1123 
1124 
1125 /*
1126  * Performs the back end of a vt switch. Called under the console
1127  * semaphore.
1128  */
complete_change_console(struct vc_data * vc)1129 static void complete_change_console(struct vc_data *vc)
1130 {
1131 	unsigned char old_vc_mode;
1132 	int old = fg_console;
1133 
1134 	last_console = fg_console;
1135 
1136 	/*
1137 	 * If we're switching, we could be going from KD_GRAPHICS to
1138 	 * KD_TEXT mode or vice versa, which means we need to blank or
1139 	 * unblank the screen later.
1140 	 */
1141 	old_vc_mode = vc_cons[fg_console].d->vc_mode;
1142 	switch_screen(vc);
1143 
1144 	/*
1145 	 * This can't appear below a successful kill_pid().  If it did,
1146 	 * then the *blank_screen operation could occur while X, having
1147 	 * received acqsig, is waking up on another processor.  This
1148 	 * condition can lead to overlapping accesses to the VGA range
1149 	 * and the framebuffer (causing system lockups).
1150 	 *
1151 	 * To account for this we duplicate this code below only if the
1152 	 * controlling process is gone and we've called reset_vc.
1153 	 */
1154 	if (old_vc_mode != vc->vc_mode) {
1155 		if (vc->vc_mode == KD_TEXT)
1156 			do_unblank_screen(1);
1157 		else
1158 			do_blank_screen(1);
1159 	}
1160 
1161 	/*
1162 	 * If this new console is under process control, send it a signal
1163 	 * telling it that it has acquired. Also check if it has died and
1164 	 * clean up (similar to logic employed in change_console())
1165 	 */
1166 	if (vc->vt_mode.mode == VT_PROCESS) {
1167 		/*
1168 		 * Send the signal as privileged - kill_pid() will
1169 		 * tell us if the process has gone or something else
1170 		 * is awry
1171 		 */
1172 		if (kill_pid(vc->vt_pid, vc->vt_mode.acqsig, 1) != 0) {
1173 		/*
1174 		 * The controlling process has died, so we revert back to
1175 		 * normal operation. In this case, we'll also change back
1176 		 * to KD_TEXT mode. I'm not sure if this is strictly correct
1177 		 * but it saves the agony when the X server dies and the screen
1178 		 * remains blanked due to KD_GRAPHICS! It would be nice to do
1179 		 * this outside of VT_PROCESS but there is no single process
1180 		 * to account for and tracking tty count may be undesirable.
1181 		 */
1182 			reset_vc(vc);
1183 
1184 			if (old_vc_mode != vc->vc_mode) {
1185 				if (vc->vc_mode == KD_TEXT)
1186 					do_unblank_screen(1);
1187 				else
1188 					do_blank_screen(1);
1189 			}
1190 		}
1191 	}
1192 
1193 	/*
1194 	 * Wake anyone waiting for their VT to activate
1195 	 */
1196 	vt_event_post(VT_EVENT_SWITCH, old, vc->vc_num);
1197 	return;
1198 }
1199 
1200 /*
1201  * Performs the front-end of a vt switch
1202  */
change_console(struct vc_data * new_vc)1203 void change_console(struct vc_data *new_vc)
1204 {
1205 	struct vc_data *vc;
1206 
1207 	if (!new_vc || new_vc->vc_num == fg_console || vt_dont_switch)
1208 		return;
1209 
1210 	/*
1211 	 * If this vt is in process mode, then we need to handshake with
1212 	 * that process before switching. Essentially, we store where that
1213 	 * vt wants to switch to and wait for it to tell us when it's done
1214 	 * (via VT_RELDISP ioctl).
1215 	 *
1216 	 * We also check to see if the controlling process still exists.
1217 	 * If it doesn't, we reset this vt to auto mode and continue.
1218 	 * This is a cheap way to track process control. The worst thing
1219 	 * that can happen is: we send a signal to a process, it dies, and
1220 	 * the switch gets "lost" waiting for a response; hopefully, the
1221 	 * user will try again, we'll detect the process is gone (unless
1222 	 * the user waits just the right amount of time :-) and revert the
1223 	 * vt to auto control.
1224 	 */
1225 	vc = vc_cons[fg_console].d;
1226 	if (vc->vt_mode.mode == VT_PROCESS) {
1227 		/*
1228 		 * Send the signal as privileged - kill_pid() will
1229 		 * tell us if the process has gone or something else
1230 		 * is awry.
1231 		 *
1232 		 * We need to set vt_newvt *before* sending the signal or we
1233 		 * have a race.
1234 		 */
1235 		vc->vt_newvt = new_vc->vc_num;
1236 		if (kill_pid(vc->vt_pid, vc->vt_mode.relsig, 1) == 0) {
1237 			/*
1238 			 * It worked. Mark the vt to switch to and
1239 			 * return. The process needs to send us a
1240 			 * VT_RELDISP ioctl to complete the switch.
1241 			 */
1242 			return;
1243 		}
1244 
1245 		/*
1246 		 * The controlling process has died, so we revert back to
1247 		 * normal operation. In this case, we'll also change back
1248 		 * to KD_TEXT mode. I'm not sure if this is strictly correct
1249 		 * but it saves the agony when the X server dies and the screen
1250 		 * remains blanked due to KD_GRAPHICS! It would be nice to do
1251 		 * this outside of VT_PROCESS but there is no single process
1252 		 * to account for and tracking tty count may be undesirable.
1253 		 */
1254 		reset_vc(vc);
1255 
1256 		/*
1257 		 * Fall through to normal (VT_AUTO) handling of the switch...
1258 		 */
1259 	}
1260 
1261 	/*
1262 	 * Ignore all switches in KD_GRAPHICS+VT_AUTO mode
1263 	 */
1264 	if (vc->vc_mode == KD_GRAPHICS)
1265 		return;
1266 
1267 	complete_change_console(new_vc);
1268 }
1269 
1270 /* Perform a kernel triggered VT switch for suspend/resume */
1271 
1272 static int disable_vt_switch;
1273 
vt_move_to_console(unsigned int vt,int alloc)1274 int vt_move_to_console(unsigned int vt, int alloc)
1275 {
1276 	int prev;
1277 
1278 	console_lock();
1279 	/* Graphics mode - up to X */
1280 	if (disable_vt_switch) {
1281 		console_unlock();
1282 		return 0;
1283 	}
1284 	prev = fg_console;
1285 
1286 	if (alloc && vc_allocate(vt)) {
1287 		/* we can't have a free VC for now. Too bad,
1288 		 * we don't want to mess the screen for now. */
1289 		console_unlock();
1290 		return -ENOSPC;
1291 	}
1292 
1293 	if (set_console(vt)) {
1294 		/*
1295 		 * We're unable to switch to the SUSPEND_CONSOLE.
1296 		 * Let the calling function know so it can decide
1297 		 * what to do.
1298 		 */
1299 		console_unlock();
1300 		return -EIO;
1301 	}
1302 	console_unlock();
1303 	if (vt_waitactive(vt + 1)) {
1304 		pr_debug("Suspend: Can't switch VCs.");
1305 		return -EINTR;
1306 	}
1307 	return prev;
1308 }
1309 
1310 /*
1311  * Normally during a suspend, we allocate a new console and switch to it.
1312  * When we resume, we switch back to the original console.  This switch
1313  * can be slow, so on systems where the framebuffer can handle restoration
1314  * of video registers anyways, there's little point in doing the console
1315  * switch.  This function allows you to disable it by passing it '0'.
1316  */
pm_set_vt_switch(int do_switch)1317 void pm_set_vt_switch(int do_switch)
1318 {
1319 	console_lock();
1320 	disable_vt_switch = !do_switch;
1321 	console_unlock();
1322 }
1323 EXPORT_SYMBOL(pm_set_vt_switch);
1324