xref: /openbmc/linux/kernel/compat.c (revision 4a3fad70) 
1 /*
2  *  linux/kernel/compat.c
3  *
4  *  Kernel compatibililty routines for e.g. 32 bit syscall support
5  *  on 64 bit kernels.
6  *
7  *  Copyright (C) 2002-2003 Stephen Rothwell, IBM Corporation
8  *
9  *  This program is free software; you can redistribute it and/or modify
10  *  it under the terms of the GNU General Public License version 2 as
11  *  published by the Free Software Foundation.
12  */
13 
14 #include <linux/linkage.h>
15 #include <linux/compat.h>
16 #include <linux/errno.h>
17 #include <linux/time.h>
18 #include <linux/signal.h>
19 #include <linux/sched.h>	/* for MAX_SCHEDULE_TIMEOUT */
20 #include <linux/syscalls.h>
21 #include <linux/unistd.h>
22 #include <linux/security.h>
23 #include <linux/timex.h>
24 #include <linux/export.h>
25 #include <linux/migrate.h>
26 #include <linux/posix-timers.h>
27 #include <linux/times.h>
28 #include <linux/ptrace.h>
29 #include <linux/gfp.h>
30 
31 #include <linux/uaccess.h>
32 
33 int compat_get_timex(struct timex *txc, const struct compat_timex __user *utp)
34 {
35 	struct compat_timex tx32;
36 
37 	if (copy_from_user(&tx32, utp, sizeof(struct compat_timex)))
38 		return -EFAULT;
39 
40 	txc->modes = tx32.modes;
41 	txc->offset = tx32.offset;
42 	txc->freq = tx32.freq;
43 	txc->maxerror = tx32.maxerror;
44 	txc->esterror = tx32.esterror;
45 	txc->status = tx32.status;
46 	txc->constant = tx32.constant;
47 	txc->precision = tx32.precision;
48 	txc->tolerance = tx32.tolerance;
49 	txc->time.tv_sec = tx32.time.tv_sec;
50 	txc->time.tv_usec = tx32.time.tv_usec;
51 	txc->tick = tx32.tick;
52 	txc->ppsfreq = tx32.ppsfreq;
53 	txc->jitter = tx32.jitter;
54 	txc->shift = tx32.shift;
55 	txc->stabil = tx32.stabil;
56 	txc->jitcnt = tx32.jitcnt;
57 	txc->calcnt = tx32.calcnt;
58 	txc->errcnt = tx32.errcnt;
59 	txc->stbcnt = tx32.stbcnt;
60 
61 	return 0;
62 }
63 
64 int compat_put_timex(struct compat_timex __user *utp, const struct timex *txc)
65 {
66 	struct compat_timex tx32;
67 
68 	memset(&tx32, 0, sizeof(struct compat_timex));
69 	tx32.modes = txc->modes;
70 	tx32.offset = txc->offset;
71 	tx32.freq = txc->freq;
72 	tx32.maxerror = txc->maxerror;
73 	tx32.esterror = txc->esterror;
74 	tx32.status = txc->status;
75 	tx32.constant = txc->constant;
76 	tx32.precision = txc->precision;
77 	tx32.tolerance = txc->tolerance;
78 	tx32.time.tv_sec = txc->time.tv_sec;
79 	tx32.time.tv_usec = txc->time.tv_usec;
80 	tx32.tick = txc->tick;
81 	tx32.ppsfreq = txc->ppsfreq;
82 	tx32.jitter = txc->jitter;
83 	tx32.shift = txc->shift;
84 	tx32.stabil = txc->stabil;
85 	tx32.jitcnt = txc->jitcnt;
86 	tx32.calcnt = txc->calcnt;
87 	tx32.errcnt = txc->errcnt;
88 	tx32.stbcnt = txc->stbcnt;
89 	tx32.tai = txc->tai;
90 	if (copy_to_user(utp, &tx32, sizeof(struct compat_timex)))
91 		return -EFAULT;
92 	return 0;
93 }
94 
95 static int __compat_get_timeval(struct timeval *tv, const struct compat_timeval __user *ctv)
96 {
97 	return (!access_ok(VERIFY_READ, ctv, sizeof(*ctv)) ||
98 			__get_user(tv->tv_sec, &ctv->tv_sec) ||
99 			__get_user(tv->tv_usec, &ctv->tv_usec)) ? -EFAULT : 0;
100 }
101 
102 static int __compat_put_timeval(const struct timeval *tv, struct compat_timeval __user *ctv)
103 {
104 	return (!access_ok(VERIFY_WRITE, ctv, sizeof(*ctv)) ||
105 			__put_user(tv->tv_sec, &ctv->tv_sec) ||
106 			__put_user(tv->tv_usec, &ctv->tv_usec)) ? -EFAULT : 0;
107 }
108 
109 static int __compat_get_timespec(struct timespec *ts, const struct compat_timespec __user *cts)
110 {
111 	return (!access_ok(VERIFY_READ, cts, sizeof(*cts)) ||
112 			__get_user(ts->tv_sec, &cts->tv_sec) ||
113 			__get_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
114 }
115 
116 static int __compat_put_timespec(const struct timespec *ts, struct compat_timespec __user *cts)
117 {
118 	return (!access_ok(VERIFY_WRITE, cts, sizeof(*cts)) ||
119 			__put_user(ts->tv_sec, &cts->tv_sec) ||
120 			__put_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
121 }
122 
123 static int __compat_get_timespec64(struct timespec64 *ts64,
124 				   const struct compat_timespec __user *cts)
125 {
126 	struct compat_timespec ts;
127 	int ret;
128 
129 	ret = copy_from_user(&ts, cts, sizeof(ts));
130 	if (ret)
131 		return -EFAULT;
132 
133 	ts64->tv_sec = ts.tv_sec;
134 	ts64->tv_nsec = ts.tv_nsec;
135 
136 	return 0;
137 }
138 
139 static int __compat_put_timespec64(const struct timespec64 *ts64,
140 				   struct compat_timespec __user *cts)
141 {
142 	struct compat_timespec ts = {
143 		.tv_sec = ts64->tv_sec,
144 		.tv_nsec = ts64->tv_nsec
145 	};
146 	return copy_to_user(cts, &ts, sizeof(ts)) ? -EFAULT : 0;
147 }
148 
149 int compat_get_timespec64(struct timespec64 *ts, const void __user *uts)
150 {
151 	if (COMPAT_USE_64BIT_TIME)
152 		return copy_from_user(ts, uts, sizeof(*ts)) ? -EFAULT : 0;
153 	else
154 		return __compat_get_timespec64(ts, uts);
155 }
156 EXPORT_SYMBOL_GPL(compat_get_timespec64);
157 
158 int compat_put_timespec64(const struct timespec64 *ts, void __user *uts)
159 {
160 	if (COMPAT_USE_64BIT_TIME)
161 		return copy_to_user(uts, ts, sizeof(*ts)) ? -EFAULT : 0;
162 	else
163 		return __compat_put_timespec64(ts, uts);
164 }
165 EXPORT_SYMBOL_GPL(compat_put_timespec64);
166 
167 int compat_get_timeval(struct timeval *tv, const void __user *utv)
168 {
169 	if (COMPAT_USE_64BIT_TIME)
170 		return copy_from_user(tv, utv, sizeof(*tv)) ? -EFAULT : 0;
171 	else
172 		return __compat_get_timeval(tv, utv);
173 }
174 EXPORT_SYMBOL_GPL(compat_get_timeval);
175 
176 int compat_put_timeval(const struct timeval *tv, void __user *utv)
177 {
178 	if (COMPAT_USE_64BIT_TIME)
179 		return copy_to_user(utv, tv, sizeof(*tv)) ? -EFAULT : 0;
180 	else
181 		return __compat_put_timeval(tv, utv);
182 }
183 EXPORT_SYMBOL_GPL(compat_put_timeval);
184 
185 int compat_get_timespec(struct timespec *ts, const void __user *uts)
186 {
187 	if (COMPAT_USE_64BIT_TIME)
188 		return copy_from_user(ts, uts, sizeof(*ts)) ? -EFAULT : 0;
189 	else
190 		return __compat_get_timespec(ts, uts);
191 }
192 EXPORT_SYMBOL_GPL(compat_get_timespec);
193 
194 int compat_put_timespec(const struct timespec *ts, void __user *uts)
195 {
196 	if (COMPAT_USE_64BIT_TIME)
197 		return copy_to_user(uts, ts, sizeof(*ts)) ? -EFAULT : 0;
198 	else
199 		return __compat_put_timespec(ts, uts);
200 }
201 EXPORT_SYMBOL_GPL(compat_put_timespec);
202 
203 int get_compat_itimerval(struct itimerval *o, const struct compat_itimerval __user *i)
204 {
205 	struct compat_itimerval v32;
206 
207 	if (copy_from_user(&v32, i, sizeof(struct compat_itimerval)))
208 		return -EFAULT;
209 	o->it_interval.tv_sec = v32.it_interval.tv_sec;
210 	o->it_interval.tv_usec = v32.it_interval.tv_usec;
211 	o->it_value.tv_sec = v32.it_value.tv_sec;
212 	o->it_value.tv_usec = v32.it_value.tv_usec;
213 	return 0;
214 }
215 
216 int put_compat_itimerval(struct compat_itimerval __user *o, const struct itimerval *i)
217 {
218 	struct compat_itimerval v32;
219 
220 	v32.it_interval.tv_sec = i->it_interval.tv_sec;
221 	v32.it_interval.tv_usec = i->it_interval.tv_usec;
222 	v32.it_value.tv_sec = i->it_value.tv_sec;
223 	v32.it_value.tv_usec = i->it_value.tv_usec;
224 	return copy_to_user(o, &v32, sizeof(struct compat_itimerval)) ? -EFAULT : 0;
225 }
226 
227 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
228 
229 /*
230  * sys_sigprocmask SIG_SETMASK sets the first (compat) word of the
231  * blocked set of signals to the supplied signal set
232  */
233 static inline void compat_sig_setmask(sigset_t *blocked, compat_sigset_word set)
234 {
235 	memcpy(blocked->sig, &set, sizeof(set));
236 }
237 
238 COMPAT_SYSCALL_DEFINE3(sigprocmask, int, how,
239 		       compat_old_sigset_t __user *, nset,
240 		       compat_old_sigset_t __user *, oset)
241 {
242 	old_sigset_t old_set, new_set;
243 	sigset_t new_blocked;
244 
245 	old_set = current->blocked.sig[0];
246 
247 	if (nset) {
248 		if (get_user(new_set, nset))
249 			return -EFAULT;
250 		new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
251 
252 		new_blocked = current->blocked;
253 
254 		switch (how) {
255 		case SIG_BLOCK:
256 			sigaddsetmask(&new_blocked, new_set);
257 			break;
258 		case SIG_UNBLOCK:
259 			sigdelsetmask(&new_blocked, new_set);
260 			break;
261 		case SIG_SETMASK:
262 			compat_sig_setmask(&new_blocked, new_set);
263 			break;
264 		default:
265 			return -EINVAL;
266 		}
267 
268 		set_current_blocked(&new_blocked);
269 	}
270 
271 	if (oset) {
272 		if (put_user(old_set, oset))
273 			return -EFAULT;
274 	}
275 
276 	return 0;
277 }
278 
279 #endif
280 
281 int put_compat_rusage(const struct rusage *r, struct compat_rusage __user *ru)
282 {
283 	struct compat_rusage r32;
284 	memset(&r32, 0, sizeof(r32));
285 	r32.ru_utime.tv_sec = r->ru_utime.tv_sec;
286 	r32.ru_utime.tv_usec = r->ru_utime.tv_usec;
287 	r32.ru_stime.tv_sec = r->ru_stime.tv_sec;
288 	r32.ru_stime.tv_usec = r->ru_stime.tv_usec;
289 	r32.ru_maxrss = r->ru_maxrss;
290 	r32.ru_ixrss = r->ru_ixrss;
291 	r32.ru_idrss = r->ru_idrss;
292 	r32.ru_isrss = r->ru_isrss;
293 	r32.ru_minflt = r->ru_minflt;
294 	r32.ru_majflt = r->ru_majflt;
295 	r32.ru_nswap = r->ru_nswap;
296 	r32.ru_inblock = r->ru_inblock;
297 	r32.ru_oublock = r->ru_oublock;
298 	r32.ru_msgsnd = r->ru_msgsnd;
299 	r32.ru_msgrcv = r->ru_msgrcv;
300 	r32.ru_nsignals = r->ru_nsignals;
301 	r32.ru_nvcsw = r->ru_nvcsw;
302 	r32.ru_nivcsw = r->ru_nivcsw;
303 	if (copy_to_user(ru, &r32, sizeof(r32)))
304 		return -EFAULT;
305 	return 0;
306 }
307 
308 static int compat_get_user_cpu_mask(compat_ulong_t __user *user_mask_ptr,
309 				    unsigned len, struct cpumask *new_mask)
310 {
311 	unsigned long *k;
312 
313 	if (len < cpumask_size())
314 		memset(new_mask, 0, cpumask_size());
315 	else if (len > cpumask_size())
316 		len = cpumask_size();
317 
318 	k = cpumask_bits(new_mask);
319 	return compat_get_bitmap(k, user_mask_ptr, len * 8);
320 }
321 
322 COMPAT_SYSCALL_DEFINE3(sched_setaffinity, compat_pid_t, pid,
323 		       unsigned int, len,
324 		       compat_ulong_t __user *, user_mask_ptr)
325 {
326 	cpumask_var_t new_mask;
327 	int retval;
328 
329 	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
330 		return -ENOMEM;
331 
332 	retval = compat_get_user_cpu_mask(user_mask_ptr, len, new_mask);
333 	if (retval)
334 		goto out;
335 
336 	retval = sched_setaffinity(pid, new_mask);
337 out:
338 	free_cpumask_var(new_mask);
339 	return retval;
340 }
341 
342 COMPAT_SYSCALL_DEFINE3(sched_getaffinity, compat_pid_t,  pid, unsigned int, len,
343 		       compat_ulong_t __user *, user_mask_ptr)
344 {
345 	int ret;
346 	cpumask_var_t mask;
347 
348 	if ((len * BITS_PER_BYTE) < nr_cpu_ids)
349 		return -EINVAL;
350 	if (len & (sizeof(compat_ulong_t)-1))
351 		return -EINVAL;
352 
353 	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
354 		return -ENOMEM;
355 
356 	ret = sched_getaffinity(pid, mask);
357 	if (ret == 0) {
358 		size_t retlen = min_t(size_t, len, cpumask_size());
359 
360 		if (compat_put_bitmap(user_mask_ptr, cpumask_bits(mask), retlen * 8))
361 			ret = -EFAULT;
362 		else
363 			ret = retlen;
364 	}
365 	free_cpumask_var(mask);
366 
367 	return ret;
368 }
369 
370 int get_compat_itimerspec64(struct itimerspec64 *its,
371 			const struct compat_itimerspec __user *uits)
372 {
373 
374 	if (__compat_get_timespec64(&its->it_interval, &uits->it_interval) ||
375 	    __compat_get_timespec64(&its->it_value, &uits->it_value))
376 		return -EFAULT;
377 	return 0;
378 }
379 EXPORT_SYMBOL_GPL(get_compat_itimerspec64);
380 
381 int put_compat_itimerspec64(const struct itimerspec64 *its,
382 			struct compat_itimerspec __user *uits)
383 {
384 	if (__compat_put_timespec64(&its->it_interval, &uits->it_interval) ||
385 	    __compat_put_timespec64(&its->it_value, &uits->it_value))
386 		return -EFAULT;
387 	return 0;
388 }
389 EXPORT_SYMBOL_GPL(put_compat_itimerspec64);
390 
391 /*
392  * We currently only need the following fields from the sigevent
393  * structure: sigev_value, sigev_signo, sig_notify and (sometimes
394  * sigev_notify_thread_id).  The others are handled in user mode.
395  * We also assume that copying sigev_value.sival_int is sufficient
396  * to keep all the bits of sigev_value.sival_ptr intact.
397  */
398 int get_compat_sigevent(struct sigevent *event,
399 		const struct compat_sigevent __user *u_event)
400 {
401 	memset(event, 0, sizeof(*event));
402 	return (!access_ok(VERIFY_READ, u_event, sizeof(*u_event)) ||
403 		__get_user(event->sigev_value.sival_int,
404 			&u_event->sigev_value.sival_int) ||
405 		__get_user(event->sigev_signo, &u_event->sigev_signo) ||
406 		__get_user(event->sigev_notify, &u_event->sigev_notify) ||
407 		__get_user(event->sigev_notify_thread_id,
408 			&u_event->sigev_notify_thread_id))
409 		? -EFAULT : 0;
410 }
411 
412 long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask,
413 		       unsigned long bitmap_size)
414 {
415 	unsigned long nr_compat_longs;
416 
417 	/* align bitmap up to nearest compat_long_t boundary */
418 	bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
419 	nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
420 
421 	if (!access_ok(VERIFY_READ, umask, bitmap_size / 8))
422 		return -EFAULT;
423 
424 	user_access_begin();
425 	while (nr_compat_longs > 1) {
426 		compat_ulong_t l1, l2;
427 		unsafe_get_user(l1, umask++, Efault);
428 		unsafe_get_user(l2, umask++, Efault);
429 		*mask++ = ((unsigned long)l2 << BITS_PER_COMPAT_LONG) | l1;
430 		nr_compat_longs -= 2;
431 	}
432 	if (nr_compat_longs)
433 		unsafe_get_user(*mask, umask++, Efault);
434 	user_access_end();
435 	return 0;
436 
437 Efault:
438 	user_access_end();
439 	return -EFAULT;
440 }
441 
442 long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
443 		       unsigned long bitmap_size)
444 {
445 	unsigned long nr_compat_longs;
446 
447 	/* align bitmap up to nearest compat_long_t boundary */
448 	bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
449 	nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
450 
451 	if (!access_ok(VERIFY_WRITE, umask, bitmap_size / 8))
452 		return -EFAULT;
453 
454 	user_access_begin();
455 	while (nr_compat_longs > 1) {
456 		unsigned long m = *mask++;
457 		unsafe_put_user((compat_ulong_t)m, umask++, Efault);
458 		unsafe_put_user(m >> BITS_PER_COMPAT_LONG, umask++, Efault);
459 		nr_compat_longs -= 2;
460 	}
461 	if (nr_compat_longs)
462 		unsafe_put_user((compat_ulong_t)*mask, umask++, Efault);
463 	user_access_end();
464 	return 0;
465 Efault:
466 	user_access_end();
467 	return -EFAULT;
468 }
469 
470 int
471 get_compat_sigset(sigset_t *set, const compat_sigset_t __user *compat)
472 {
473 #ifdef __BIG_ENDIAN
474 	compat_sigset_t v;
475 	if (copy_from_user(&v, compat, sizeof(compat_sigset_t)))
476 		return -EFAULT;
477 	switch (_NSIG_WORDS) {
478 	case 4: set->sig[3] = v.sig[6] | (((long)v.sig[7]) << 32 );
479 	case 3: set->sig[2] = v.sig[4] | (((long)v.sig[5]) << 32 );
480 	case 2: set->sig[1] = v.sig[2] | (((long)v.sig[3]) << 32 );
481 	case 1: set->sig[0] = v.sig[0] | (((long)v.sig[1]) << 32 );
482 	}
483 #else
484 	if (copy_from_user(set, compat, sizeof(compat_sigset_t)))
485 		return -EFAULT;
486 #endif
487 	return 0;
488 }
489 EXPORT_SYMBOL_GPL(get_compat_sigset);
490 
491 int
492 put_compat_sigset(compat_sigset_t __user *compat, const sigset_t *set,
493 		  unsigned int size)
494 {
495 	/* size <= sizeof(compat_sigset_t) <= sizeof(sigset_t) */
496 #ifdef __BIG_ENDIAN
497 	compat_sigset_t v;
498 	switch (_NSIG_WORDS) {
499 	case 4: v.sig[7] = (set->sig[3] >> 32); v.sig[6] = set->sig[3];
500 	case 3: v.sig[5] = (set->sig[2] >> 32); v.sig[4] = set->sig[2];
501 	case 2: v.sig[3] = (set->sig[1] >> 32); v.sig[2] = set->sig[1];
502 	case 1: v.sig[1] = (set->sig[0] >> 32); v.sig[0] = set->sig[0];
503 	}
504 	return copy_to_user(compat, &v, size) ? -EFAULT : 0;
505 #else
506 	return copy_to_user(compat, set, size) ? -EFAULT : 0;
507 #endif
508 }
509 
510 #ifdef CONFIG_NUMA
511 COMPAT_SYSCALL_DEFINE6(move_pages, pid_t, pid, compat_ulong_t, nr_pages,
512 		       compat_uptr_t __user *, pages32,
513 		       const int __user *, nodes,
514 		       int __user *, status,
515 		       int, flags)
516 {
517 	const void __user * __user *pages;
518 	int i;
519 
520 	pages = compat_alloc_user_space(nr_pages * sizeof(void *));
521 	for (i = 0; i < nr_pages; i++) {
522 		compat_uptr_t p;
523 
524 		if (get_user(p, pages32 + i) ||
525 			put_user(compat_ptr(p), pages + i))
526 			return -EFAULT;
527 	}
528 	return sys_move_pages(pid, nr_pages, pages, nodes, status, flags);
529 }
530 
531 COMPAT_SYSCALL_DEFINE4(migrate_pages, compat_pid_t, pid,
532 		       compat_ulong_t, maxnode,
533 		       const compat_ulong_t __user *, old_nodes,
534 		       const compat_ulong_t __user *, new_nodes)
535 {
536 	unsigned long __user *old = NULL;
537 	unsigned long __user *new = NULL;
538 	nodemask_t tmp_mask;
539 	unsigned long nr_bits;
540 	unsigned long size;
541 
542 	nr_bits = min_t(unsigned long, maxnode - 1, MAX_NUMNODES);
543 	size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
544 	if (old_nodes) {
545 		if (compat_get_bitmap(nodes_addr(tmp_mask), old_nodes, nr_bits))
546 			return -EFAULT;
547 		old = compat_alloc_user_space(new_nodes ? size * 2 : size);
548 		if (new_nodes)
549 			new = old + size / sizeof(unsigned long);
550 		if (copy_to_user(old, nodes_addr(tmp_mask), size))
551 			return -EFAULT;
552 	}
553 	if (new_nodes) {
554 		if (compat_get_bitmap(nodes_addr(tmp_mask), new_nodes, nr_bits))
555 			return -EFAULT;
556 		if (new == NULL)
557 			new = compat_alloc_user_space(size);
558 		if (copy_to_user(new, nodes_addr(tmp_mask), size))
559 			return -EFAULT;
560 	}
561 	return sys_migrate_pages(pid, nr_bits + 1, old, new);
562 }
563 #endif
564 
565 /*
566  * Allocate user-space memory for the duration of a single system call,
567  * in order to marshall parameters inside a compat thunk.
568  */
569 void __user *compat_alloc_user_space(unsigned long len)
570 {
571 	void __user *ptr;
572 
573 	/* If len would occupy more than half of the entire compat space... */
574 	if (unlikely(len > (((compat_uptr_t)~0) >> 1)))
575 		return NULL;
576 
577 	ptr = arch_compat_alloc_user_space(len);
578 
579 	if (unlikely(!access_ok(VERIFY_WRITE, ptr, len)))
580 		return NULL;
581 
582 	return ptr;
583 }
584 EXPORT_SYMBOL_GPL(compat_alloc_user_space);
585