xref: /linux-6.15/kernel/compat.c (revision d5b7ffbf)
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 compat_convert_timespec(struct timespec __user **kts,
204 			    const void __user *cts)
205 {
206 	struct timespec ts;
207 	struct timespec __user *uts;
208 
209 	if (!cts || COMPAT_USE_64BIT_TIME) {
210 		*kts = (struct timespec __user *)cts;
211 		return 0;
212 	}
213 
214 	uts = compat_alloc_user_space(sizeof(ts));
215 	if (!uts)
216 		return -EFAULT;
217 	if (compat_get_timespec(&ts, cts))
218 		return -EFAULT;
219 	if (copy_to_user(uts, &ts, sizeof(ts)))
220 		return -EFAULT;
221 
222 	*kts = uts;
223 	return 0;
224 }
225 
226 int get_compat_itimerval(struct itimerval *o, const struct compat_itimerval __user *i)
227 {
228 	struct compat_itimerval v32;
229 
230 	if (copy_from_user(&v32, i, sizeof(struct compat_itimerval)))
231 		return -EFAULT;
232 	o->it_interval.tv_sec = v32.it_interval.tv_sec;
233 	o->it_interval.tv_usec = v32.it_interval.tv_usec;
234 	o->it_value.tv_sec = v32.it_value.tv_sec;
235 	o->it_value.tv_usec = v32.it_value.tv_usec;
236 	return 0;
237 }
238 
239 int put_compat_itimerval(struct compat_itimerval __user *o, const struct itimerval *i)
240 {
241 	struct compat_itimerval v32;
242 
243 	v32.it_interval.tv_sec = i->it_interval.tv_sec;
244 	v32.it_interval.tv_usec = i->it_interval.tv_usec;
245 	v32.it_value.tv_sec = i->it_value.tv_sec;
246 	v32.it_value.tv_usec = i->it_value.tv_usec;
247 	return copy_to_user(o, &v32, sizeof(struct compat_itimerval)) ? -EFAULT : 0;
248 }
249 
250 static compat_clock_t clock_t_to_compat_clock_t(clock_t x)
251 {
252 	return compat_jiffies_to_clock_t(clock_t_to_jiffies(x));
253 }
254 
255 COMPAT_SYSCALL_DEFINE1(times, struct compat_tms __user *, tbuf)
256 {
257 	if (tbuf) {
258 		struct tms tms;
259 		struct compat_tms tmp;
260 
261 		do_sys_times(&tms);
262 		/* Convert our struct tms to the compat version. */
263 		tmp.tms_utime = clock_t_to_compat_clock_t(tms.tms_utime);
264 		tmp.tms_stime = clock_t_to_compat_clock_t(tms.tms_stime);
265 		tmp.tms_cutime = clock_t_to_compat_clock_t(tms.tms_cutime);
266 		tmp.tms_cstime = clock_t_to_compat_clock_t(tms.tms_cstime);
267 		if (copy_to_user(tbuf, &tmp, sizeof(tmp)))
268 			return -EFAULT;
269 	}
270 	force_successful_syscall_return();
271 	return compat_jiffies_to_clock_t(jiffies);
272 }
273 
274 #ifdef __ARCH_WANT_SYS_SIGPENDING
275 
276 /*
277  * Assumption: old_sigset_t and compat_old_sigset_t are both
278  * types that can be passed to put_user()/get_user().
279  */
280 
281 COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set)
282 {
283 	old_sigset_t s;
284 	long ret;
285 	mm_segment_t old_fs = get_fs();
286 
287 	set_fs(KERNEL_DS);
288 	ret = sys_sigpending((old_sigset_t __user *) &s);
289 	set_fs(old_fs);
290 	if (ret == 0)
291 		ret = put_user(s, set);
292 	return ret;
293 }
294 
295 #endif
296 
297 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
298 
299 /*
300  * sys_sigprocmask SIG_SETMASK sets the first (compat) word of the
301  * blocked set of signals to the supplied signal set
302  */
303 static inline void compat_sig_setmask(sigset_t *blocked, compat_sigset_word set)
304 {
305 	memcpy(blocked->sig, &set, sizeof(set));
306 }
307 
308 COMPAT_SYSCALL_DEFINE3(sigprocmask, int, how,
309 		       compat_old_sigset_t __user *, nset,
310 		       compat_old_sigset_t __user *, oset)
311 {
312 	old_sigset_t old_set, new_set;
313 	sigset_t new_blocked;
314 
315 	old_set = current->blocked.sig[0];
316 
317 	if (nset) {
318 		if (get_user(new_set, nset))
319 			return -EFAULT;
320 		new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
321 
322 		new_blocked = current->blocked;
323 
324 		switch (how) {
325 		case SIG_BLOCK:
326 			sigaddsetmask(&new_blocked, new_set);
327 			break;
328 		case SIG_UNBLOCK:
329 			sigdelsetmask(&new_blocked, new_set);
330 			break;
331 		case SIG_SETMASK:
332 			compat_sig_setmask(&new_blocked, new_set);
333 			break;
334 		default:
335 			return -EINVAL;
336 		}
337 
338 		set_current_blocked(&new_blocked);
339 	}
340 
341 	if (oset) {
342 		if (put_user(old_set, oset))
343 			return -EFAULT;
344 	}
345 
346 	return 0;
347 }
348 
349 #endif
350 
351 COMPAT_SYSCALL_DEFINE2(setrlimit, unsigned int, resource,
352 		       struct compat_rlimit __user *, rlim)
353 {
354 	struct rlimit r;
355 
356 	if (!access_ok(VERIFY_READ, rlim, sizeof(*rlim)) ||
357 	    __get_user(r.rlim_cur, &rlim->rlim_cur) ||
358 	    __get_user(r.rlim_max, &rlim->rlim_max))
359 		return -EFAULT;
360 
361 	if (r.rlim_cur == COMPAT_RLIM_INFINITY)
362 		r.rlim_cur = RLIM_INFINITY;
363 	if (r.rlim_max == COMPAT_RLIM_INFINITY)
364 		r.rlim_max = RLIM_INFINITY;
365 	return do_prlimit(current, resource, &r, NULL);
366 }
367 
368 #ifdef COMPAT_RLIM_OLD_INFINITY
369 
370 COMPAT_SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
371 		       struct compat_rlimit __user *, rlim)
372 {
373 	struct rlimit r;
374 	int ret;
375 	mm_segment_t old_fs = get_fs();
376 
377 	set_fs(KERNEL_DS);
378 	ret = sys_old_getrlimit(resource, (struct rlimit __user *)&r);
379 	set_fs(old_fs);
380 
381 	if (!ret) {
382 		if (r.rlim_cur > COMPAT_RLIM_OLD_INFINITY)
383 			r.rlim_cur = COMPAT_RLIM_INFINITY;
384 		if (r.rlim_max > COMPAT_RLIM_OLD_INFINITY)
385 			r.rlim_max = COMPAT_RLIM_INFINITY;
386 
387 		if (!access_ok(VERIFY_WRITE, rlim, sizeof(*rlim)) ||
388 		    __put_user(r.rlim_cur, &rlim->rlim_cur) ||
389 		    __put_user(r.rlim_max, &rlim->rlim_max))
390 			return -EFAULT;
391 	}
392 	return ret;
393 }
394 
395 #endif
396 
397 COMPAT_SYSCALL_DEFINE2(getrlimit, unsigned int, resource,
398 		       struct compat_rlimit __user *, rlim)
399 {
400 	struct rlimit r;
401 	int ret;
402 
403 	ret = do_prlimit(current, resource, NULL, &r);
404 	if (!ret) {
405 		if (r.rlim_cur > COMPAT_RLIM_INFINITY)
406 			r.rlim_cur = COMPAT_RLIM_INFINITY;
407 		if (r.rlim_max > COMPAT_RLIM_INFINITY)
408 			r.rlim_max = COMPAT_RLIM_INFINITY;
409 
410 		if (!access_ok(VERIFY_WRITE, rlim, sizeof(*rlim)) ||
411 		    __put_user(r.rlim_cur, &rlim->rlim_cur) ||
412 		    __put_user(r.rlim_max, &rlim->rlim_max))
413 			return -EFAULT;
414 	}
415 	return ret;
416 }
417 
418 int put_compat_rusage(const struct rusage *r, struct compat_rusage __user *ru)
419 {
420 	if (!access_ok(VERIFY_WRITE, ru, sizeof(*ru)) ||
421 	    __put_user(r->ru_utime.tv_sec, &ru->ru_utime.tv_sec) ||
422 	    __put_user(r->ru_utime.tv_usec, &ru->ru_utime.tv_usec) ||
423 	    __put_user(r->ru_stime.tv_sec, &ru->ru_stime.tv_sec) ||
424 	    __put_user(r->ru_stime.tv_usec, &ru->ru_stime.tv_usec) ||
425 	    __put_user(r->ru_maxrss, &ru->ru_maxrss) ||
426 	    __put_user(r->ru_ixrss, &ru->ru_ixrss) ||
427 	    __put_user(r->ru_idrss, &ru->ru_idrss) ||
428 	    __put_user(r->ru_isrss, &ru->ru_isrss) ||
429 	    __put_user(r->ru_minflt, &ru->ru_minflt) ||
430 	    __put_user(r->ru_majflt, &ru->ru_majflt) ||
431 	    __put_user(r->ru_nswap, &ru->ru_nswap) ||
432 	    __put_user(r->ru_inblock, &ru->ru_inblock) ||
433 	    __put_user(r->ru_oublock, &ru->ru_oublock) ||
434 	    __put_user(r->ru_msgsnd, &ru->ru_msgsnd) ||
435 	    __put_user(r->ru_msgrcv, &ru->ru_msgrcv) ||
436 	    __put_user(r->ru_nsignals, &ru->ru_nsignals) ||
437 	    __put_user(r->ru_nvcsw, &ru->ru_nvcsw) ||
438 	    __put_user(r->ru_nivcsw, &ru->ru_nivcsw))
439 		return -EFAULT;
440 	return 0;
441 }
442 
443 COMPAT_SYSCALL_DEFINE4(wait4,
444 	compat_pid_t, pid,
445 	compat_uint_t __user *, stat_addr,
446 	int, options,
447 	struct compat_rusage __user *, ru)
448 {
449 	if (!ru) {
450 		return sys_wait4(pid, stat_addr, options, NULL);
451 	} else {
452 		struct rusage r;
453 		int ret;
454 		unsigned int status;
455 		mm_segment_t old_fs = get_fs();
456 
457 		set_fs (KERNEL_DS);
458 		ret = sys_wait4(pid,
459 				(stat_addr ?
460 				 (unsigned int __user *) &status : NULL),
461 				options, (struct rusage __user *) &r);
462 		set_fs (old_fs);
463 
464 		if (ret > 0) {
465 			if (put_compat_rusage(&r, ru))
466 				return -EFAULT;
467 			if (stat_addr && put_user(status, stat_addr))
468 				return -EFAULT;
469 		}
470 		return ret;
471 	}
472 }
473 
474 COMPAT_SYSCALL_DEFINE5(waitid,
475 		int, which, compat_pid_t, pid,
476 		struct compat_siginfo __user *, uinfo, int, options,
477 		struct compat_rusage __user *, uru)
478 {
479 	siginfo_t info;
480 	struct rusage ru;
481 	long ret;
482 	mm_segment_t old_fs = get_fs();
483 
484 	memset(&info, 0, sizeof(info));
485 
486 	set_fs(KERNEL_DS);
487 	ret = sys_waitid(which, pid, (siginfo_t __user *)&info, options,
488 			 uru ? (struct rusage __user *)&ru : NULL);
489 	set_fs(old_fs);
490 
491 	if ((ret < 0) || (info.si_signo == 0))
492 		return ret;
493 
494 	if (uru) {
495 		/* sys_waitid() overwrites everything in ru */
496 		if (COMPAT_USE_64BIT_TIME)
497 			ret = copy_to_user(uru, &ru, sizeof(ru));
498 		else
499 			ret = put_compat_rusage(&ru, uru);
500 		if (ret)
501 			return -EFAULT;
502 	}
503 
504 	BUG_ON(info.si_code & __SI_MASK);
505 	info.si_code |= __SI_CHLD;
506 	return copy_siginfo_to_user32(uinfo, &info);
507 }
508 
509 static int compat_get_user_cpu_mask(compat_ulong_t __user *user_mask_ptr,
510 				    unsigned len, struct cpumask *new_mask)
511 {
512 	unsigned long *k;
513 
514 	if (len < cpumask_size())
515 		memset(new_mask, 0, cpumask_size());
516 	else if (len > cpumask_size())
517 		len = cpumask_size();
518 
519 	k = cpumask_bits(new_mask);
520 	return compat_get_bitmap(k, user_mask_ptr, len * 8);
521 }
522 
523 COMPAT_SYSCALL_DEFINE3(sched_setaffinity, compat_pid_t, pid,
524 		       unsigned int, len,
525 		       compat_ulong_t __user *, user_mask_ptr)
526 {
527 	cpumask_var_t new_mask;
528 	int retval;
529 
530 	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
531 		return -ENOMEM;
532 
533 	retval = compat_get_user_cpu_mask(user_mask_ptr, len, new_mask);
534 	if (retval)
535 		goto out;
536 
537 	retval = sched_setaffinity(pid, new_mask);
538 out:
539 	free_cpumask_var(new_mask);
540 	return retval;
541 }
542 
543 COMPAT_SYSCALL_DEFINE3(sched_getaffinity, compat_pid_t,  pid, unsigned int, len,
544 		       compat_ulong_t __user *, user_mask_ptr)
545 {
546 	int ret;
547 	cpumask_var_t mask;
548 
549 	if ((len * BITS_PER_BYTE) < nr_cpu_ids)
550 		return -EINVAL;
551 	if (len & (sizeof(compat_ulong_t)-1))
552 		return -EINVAL;
553 
554 	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
555 		return -ENOMEM;
556 
557 	ret = sched_getaffinity(pid, mask);
558 	if (ret == 0) {
559 		size_t retlen = min_t(size_t, len, cpumask_size());
560 
561 		if (compat_put_bitmap(user_mask_ptr, cpumask_bits(mask), retlen * 8))
562 			ret = -EFAULT;
563 		else
564 			ret = retlen;
565 	}
566 	free_cpumask_var(mask);
567 
568 	return ret;
569 }
570 
571 int get_compat_itimerspec(struct itimerspec *dst,
572 			  const struct compat_itimerspec __user *src)
573 {
574 	if (__compat_get_timespec(&dst->it_interval, &src->it_interval) ||
575 	    __compat_get_timespec(&dst->it_value, &src->it_value))
576 		return -EFAULT;
577 	return 0;
578 }
579 
580 int put_compat_itimerspec(struct compat_itimerspec __user *dst,
581 			  const struct itimerspec *src)
582 {
583 	if (__compat_put_timespec(&src->it_interval, &dst->it_interval) ||
584 	    __compat_put_timespec(&src->it_value, &dst->it_value))
585 		return -EFAULT;
586 	return 0;
587 }
588 
589 int get_compat_itimerspec64(struct itimerspec64 *its,
590 			const struct compat_itimerspec __user *uits)
591 {
592 
593 	if (__compat_get_timespec64(&its->it_interval, &uits->it_interval) ||
594 	    __compat_get_timespec64(&its->it_value, &uits->it_value))
595 		return -EFAULT;
596 	return 0;
597 }
598 EXPORT_SYMBOL_GPL(get_compat_itimerspec64);
599 
600 int put_compat_itimerspec64(const struct itimerspec64 *its,
601 			struct compat_itimerspec __user *uits)
602 {
603 	if (__compat_put_timespec64(&its->it_interval, &uits->it_interval) ||
604 	    __compat_put_timespec64(&its->it_value, &uits->it_value))
605 		return -EFAULT;
606 	return 0;
607 }
608 EXPORT_SYMBOL_GPL(put_compat_itimerspec64);
609 
610 /*
611  * We currently only need the following fields from the sigevent
612  * structure: sigev_value, sigev_signo, sig_notify and (sometimes
613  * sigev_notify_thread_id).  The others are handled in user mode.
614  * We also assume that copying sigev_value.sival_int is sufficient
615  * to keep all the bits of sigev_value.sival_ptr intact.
616  */
617 int get_compat_sigevent(struct sigevent *event,
618 		const struct compat_sigevent __user *u_event)
619 {
620 	memset(event, 0, sizeof(*event));
621 	return (!access_ok(VERIFY_READ, u_event, sizeof(*u_event)) ||
622 		__get_user(event->sigev_value.sival_int,
623 			&u_event->sigev_value.sival_int) ||
624 		__get_user(event->sigev_signo, &u_event->sigev_signo) ||
625 		__get_user(event->sigev_notify, &u_event->sigev_notify) ||
626 		__get_user(event->sigev_notify_thread_id,
627 			&u_event->sigev_notify_thread_id))
628 		? -EFAULT : 0;
629 }
630 
631 long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask,
632 		       unsigned long bitmap_size)
633 {
634 	int i, j;
635 	unsigned long m;
636 	compat_ulong_t um;
637 	unsigned long nr_compat_longs;
638 
639 	/* align bitmap up to nearest compat_long_t boundary */
640 	bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
641 
642 	if (!access_ok(VERIFY_READ, umask, bitmap_size / 8))
643 		return -EFAULT;
644 
645 	nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
646 
647 	for (i = 0; i < BITS_TO_LONGS(bitmap_size); i++) {
648 		m = 0;
649 
650 		for (j = 0; j < sizeof(m)/sizeof(um); j++) {
651 			/*
652 			 * We dont want to read past the end of the userspace
653 			 * bitmap. We must however ensure the end of the
654 			 * kernel bitmap is zeroed.
655 			 */
656 			if (nr_compat_longs) {
657 				nr_compat_longs--;
658 				if (__get_user(um, umask))
659 					return -EFAULT;
660 			} else {
661 				um = 0;
662 			}
663 
664 			umask++;
665 			m |= (long)um << (j * BITS_PER_COMPAT_LONG);
666 		}
667 		*mask++ = m;
668 	}
669 
670 	return 0;
671 }
672 
673 long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
674 		       unsigned long bitmap_size)
675 {
676 	int i, j;
677 	unsigned long m;
678 	compat_ulong_t um;
679 	unsigned long nr_compat_longs;
680 
681 	/* align bitmap up to nearest compat_long_t boundary */
682 	bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
683 
684 	if (!access_ok(VERIFY_WRITE, umask, bitmap_size / 8))
685 		return -EFAULT;
686 
687 	nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
688 
689 	for (i = 0; i < BITS_TO_LONGS(bitmap_size); i++) {
690 		m = *mask++;
691 
692 		for (j = 0; j < sizeof(m)/sizeof(um); j++) {
693 			um = m;
694 
695 			/*
696 			 * We dont want to write past the end of the userspace
697 			 * bitmap.
698 			 */
699 			if (nr_compat_longs) {
700 				nr_compat_longs--;
701 				if (__put_user(um, umask))
702 					return -EFAULT;
703 			}
704 
705 			umask++;
706 			m >>= 4*sizeof(um);
707 			m >>= 4*sizeof(um);
708 		}
709 	}
710 
711 	return 0;
712 }
713 
714 void
715 sigset_from_compat(sigset_t *set, const compat_sigset_t *compat)
716 {
717 	switch (_NSIG_WORDS) {
718 	case 4: set->sig[3] = compat->sig[6] | (((long)compat->sig[7]) << 32 );
719 	case 3: set->sig[2] = compat->sig[4] | (((long)compat->sig[5]) << 32 );
720 	case 2: set->sig[1] = compat->sig[2] | (((long)compat->sig[3]) << 32 );
721 	case 1: set->sig[0] = compat->sig[0] | (((long)compat->sig[1]) << 32 );
722 	}
723 }
724 EXPORT_SYMBOL_GPL(sigset_from_compat);
725 
726 void
727 sigset_to_compat(compat_sigset_t *compat, const sigset_t *set)
728 {
729 	switch (_NSIG_WORDS) {
730 	case 4: compat->sig[7] = (set->sig[3] >> 32); compat->sig[6] = set->sig[3];
731 	case 3: compat->sig[5] = (set->sig[2] >> 32); compat->sig[4] = set->sig[2];
732 	case 2: compat->sig[3] = (set->sig[1] >> 32); compat->sig[2] = set->sig[1];
733 	case 1: compat->sig[1] = (set->sig[0] >> 32); compat->sig[0] = set->sig[0];
734 	}
735 }
736 
737 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait, compat_sigset_t __user *, uthese,
738 		struct compat_siginfo __user *, uinfo,
739 		struct compat_timespec __user *, uts, compat_size_t, sigsetsize)
740 {
741 	compat_sigset_t s32;
742 	sigset_t s;
743 	struct timespec t;
744 	siginfo_t info;
745 	long ret;
746 
747 	if (sigsetsize != sizeof(sigset_t))
748 		return -EINVAL;
749 
750 	if (copy_from_user(&s32, uthese, sizeof(compat_sigset_t)))
751 		return -EFAULT;
752 	sigset_from_compat(&s, &s32);
753 
754 	if (uts) {
755 		if (compat_get_timespec(&t, uts))
756 			return -EFAULT;
757 	}
758 
759 	ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
760 
761 	if (ret > 0 && uinfo) {
762 		if (copy_siginfo_to_user32(uinfo, &info))
763 			ret = -EFAULT;
764 	}
765 
766 	return ret;
767 }
768 
769 #ifdef CONFIG_NUMA
770 COMPAT_SYSCALL_DEFINE6(move_pages, pid_t, pid, compat_ulong_t, nr_pages,
771 		       compat_uptr_t __user *, pages32,
772 		       const int __user *, nodes,
773 		       int __user *, status,
774 		       int, flags)
775 {
776 	const void __user * __user *pages;
777 	int i;
778 
779 	pages = compat_alloc_user_space(nr_pages * sizeof(void *));
780 	for (i = 0; i < nr_pages; i++) {
781 		compat_uptr_t p;
782 
783 		if (get_user(p, pages32 + i) ||
784 			put_user(compat_ptr(p), pages + i))
785 			return -EFAULT;
786 	}
787 	return sys_move_pages(pid, nr_pages, pages, nodes, status, flags);
788 }
789 
790 COMPAT_SYSCALL_DEFINE4(migrate_pages, compat_pid_t, pid,
791 		       compat_ulong_t, maxnode,
792 		       const compat_ulong_t __user *, old_nodes,
793 		       const compat_ulong_t __user *, new_nodes)
794 {
795 	unsigned long __user *old = NULL;
796 	unsigned long __user *new = NULL;
797 	nodemask_t tmp_mask;
798 	unsigned long nr_bits;
799 	unsigned long size;
800 
801 	nr_bits = min_t(unsigned long, maxnode - 1, MAX_NUMNODES);
802 	size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
803 	if (old_nodes) {
804 		if (compat_get_bitmap(nodes_addr(tmp_mask), old_nodes, nr_bits))
805 			return -EFAULT;
806 		old = compat_alloc_user_space(new_nodes ? size * 2 : size);
807 		if (new_nodes)
808 			new = old + size / sizeof(unsigned long);
809 		if (copy_to_user(old, nodes_addr(tmp_mask), size))
810 			return -EFAULT;
811 	}
812 	if (new_nodes) {
813 		if (compat_get_bitmap(nodes_addr(tmp_mask), new_nodes, nr_bits))
814 			return -EFAULT;
815 		if (new == NULL)
816 			new = compat_alloc_user_space(size);
817 		if (copy_to_user(new, nodes_addr(tmp_mask), size))
818 			return -EFAULT;
819 	}
820 	return sys_migrate_pages(pid, nr_bits + 1, old, new);
821 }
822 #endif
823 
824 COMPAT_SYSCALL_DEFINE2(sched_rr_get_interval,
825 		       compat_pid_t, pid,
826 		       struct compat_timespec __user *, interval)
827 {
828 	struct timespec t;
829 	int ret;
830 	mm_segment_t old_fs = get_fs();
831 
832 	set_fs(KERNEL_DS);
833 	ret = sys_sched_rr_get_interval(pid, (struct timespec __user *)&t);
834 	set_fs(old_fs);
835 	if (compat_put_timespec(&t, interval))
836 		return -EFAULT;
837 	return ret;
838 }
839 
840 /*
841  * Allocate user-space memory for the duration of a single system call,
842  * in order to marshall parameters inside a compat thunk.
843  */
844 void __user *compat_alloc_user_space(unsigned long len)
845 {
846 	void __user *ptr;
847 
848 	/* If len would occupy more than half of the entire compat space... */
849 	if (unlikely(len > (((compat_uptr_t)~0) >> 1)))
850 		return NULL;
851 
852 	ptr = arch_compat_alloc_user_space(len);
853 
854 	if (unlikely(!access_ok(VERIFY_WRITE, ptr, len)))
855 		return NULL;
856 
857 	return ptr;
858 }
859 EXPORT_SYMBOL_GPL(compat_alloc_user_space);
860