projects/linux·blob v5.4-rc2 · refs

380 lines · 10.0 KiB

1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/kernel/compat.c
4 *
5 * Kernel compatibililty routines for e.g. 32 bit syscall support
6 * on 64 bit kernels.
7 *
8 * Copyright (C) 2002-2003 Stephen Rothwell, IBM Corporation
9 */
10
11#include <linux/linkage.h>
12#include <linux/compat.h>
13#include <linux/errno.h>
14#include <linux/time.h>
15#include <linux/signal.h>
16#include <linux/sched.h> /* for MAX_SCHEDULE_TIMEOUT */
17#include <linux/syscalls.h>
18#include <linux/unistd.h>
19#include <linux/security.h>
20#include <linux/export.h>
21#include <linux/migrate.h>
22#include <linux/posix-timers.h>
23#include <linux/times.h>
24#include <linux/ptrace.h>
25#include <linux/gfp.h>
26
27#include <linux/uaccess.h>
28
29static int __compat_get_timeval(struct timeval *tv, const struct old_timeval32 __user *ctv)
30{
31 return (!access_ok(ctv, sizeof(*ctv)) ||
32 __get_user(tv->tv_sec, &ctv->tv_sec) ||
33 __get_user(tv->tv_usec, &ctv->tv_usec)) ? -EFAULT : 0;
34}
35
36static int __compat_put_timeval(const struct timeval *tv, struct old_timeval32 __user *ctv)
37{
38 return (!access_ok(ctv, sizeof(*ctv)) ||
39 __put_user(tv->tv_sec, &ctv->tv_sec) ||
40 __put_user(tv->tv_usec, &ctv->tv_usec)) ? -EFAULT : 0;
41}
42
43static int __compat_get_timespec(struct timespec *ts, const struct old_timespec32 __user *cts)
44{
45 return (!access_ok(cts, sizeof(*cts)) ||
46 __get_user(ts->tv_sec, &cts->tv_sec) ||
47 __get_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
48}
49
50static int __compat_put_timespec(const struct timespec *ts, struct old_timespec32 __user *cts)
51{
52 return (!access_ok(cts, sizeof(*cts)) ||
53 __put_user(ts->tv_sec, &cts->tv_sec) ||
54 __put_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
55}
56
57int compat_get_timeval(struct timeval *tv, const void __user *utv)
58{
59 if (COMPAT_USE_64BIT_TIME)
60 return copy_from_user(tv, utv, sizeof(*tv)) ? -EFAULT : 0;
61 else
62 return __compat_get_timeval(tv, utv);
63}
64EXPORT_SYMBOL_GPL(compat_get_timeval);
65
66int compat_put_timeval(const struct timeval *tv, void __user *utv)
67{
68 if (COMPAT_USE_64BIT_TIME)
69 return copy_to_user(utv, tv, sizeof(*tv)) ? -EFAULT : 0;
70 else
71 return __compat_put_timeval(tv, utv);
72}
73EXPORT_SYMBOL_GPL(compat_put_timeval);
74
75int compat_get_timespec(struct timespec *ts, const void __user *uts)
76{
77 if (COMPAT_USE_64BIT_TIME)
78 return copy_from_user(ts, uts, sizeof(*ts)) ? -EFAULT : 0;
79 else
80 return __compat_get_timespec(ts, uts);
81}
82EXPORT_SYMBOL_GPL(compat_get_timespec);
83
84int compat_put_timespec(const struct timespec *ts, void __user *uts)
85{
86 if (COMPAT_USE_64BIT_TIME)
87 return copy_to_user(uts, ts, sizeof(*ts)) ? -EFAULT : 0;
88 else
89 return __compat_put_timespec(ts, uts);
90}
91EXPORT_SYMBOL_GPL(compat_put_timespec);
92
93int get_compat_itimerval(struct itimerval *o, const struct compat_itimerval __user *i)
94{
95 struct compat_itimerval v32;
96
97 if (copy_from_user(&v32, i, sizeof(struct compat_itimerval)))
98 return -EFAULT;
99 o->it_interval.tv_sec = v32.it_interval.tv_sec;
100 o->it_interval.tv_usec = v32.it_interval.tv_usec;
101 o->it_value.tv_sec = v32.it_value.tv_sec;
102 o->it_value.tv_usec = v32.it_value.tv_usec;
103 return 0;
104}
105
106int put_compat_itimerval(struct compat_itimerval __user *o, const struct itimerval *i)
107{
108 struct compat_itimerval v32;
109
110 v32.it_interval.tv_sec = i->it_interval.tv_sec;
111 v32.it_interval.tv_usec = i->it_interval.tv_usec;
112 v32.it_value.tv_sec = i->it_value.tv_sec;
113 v32.it_value.tv_usec = i->it_value.tv_usec;
114 return copy_to_user(o, &v32, sizeof(struct compat_itimerval)) ? -EFAULT : 0;
115}
116
117#ifdef __ARCH_WANT_SYS_SIGPROCMASK
118
119/*
120 * sys_sigprocmask SIG_SETMASK sets the first (compat) word of the
121 * blocked set of signals to the supplied signal set
122 */
123static inline void compat_sig_setmask(sigset_t *blocked, compat_sigset_word set)
124{
125 memcpy(blocked->sig, &set, sizeof(set));
126}
127
128COMPAT_SYSCALL_DEFINE3(sigprocmask, int, how,
129 compat_old_sigset_t __user *, nset,
130 compat_old_sigset_t __user *, oset)
131{
132 old_sigset_t old_set, new_set;
133 sigset_t new_blocked;
134
135 old_set = current->blocked.sig[0];
136
137 if (nset) {
138 if (get_user(new_set, nset))
139 return -EFAULT;
140 new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
141
142 new_blocked = current->blocked;
143
144 switch (how) {
145 case SIG_BLOCK:
146 sigaddsetmask(&new_blocked, new_set);
147 break;
148 case SIG_UNBLOCK:
149 sigdelsetmask(&new_blocked, new_set);
150 break;
151 case SIG_SETMASK:
152 compat_sig_setmask(&new_blocked, new_set);
153 break;
154 default:
155 return -EINVAL;
156 }
157
158 set_current_blocked(&new_blocked);
159 }
160
161 if (oset) {
162 if (put_user(old_set, oset))
163 return -EFAULT;
164 }
165
166 return 0;
167}
168
169#endif
170
171int put_compat_rusage(const struct rusage *r, struct compat_rusage __user *ru)
172{
173 struct compat_rusage r32;
174 memset(&r32, 0, sizeof(r32));
175 r32.ru_utime.tv_sec = r->ru_utime.tv_sec;
176 r32.ru_utime.tv_usec = r->ru_utime.tv_usec;
177 r32.ru_stime.tv_sec = r->ru_stime.tv_sec;
178 r32.ru_stime.tv_usec = r->ru_stime.tv_usec;
179 r32.ru_maxrss = r->ru_maxrss;
180 r32.ru_ixrss = r->ru_ixrss;
181 r32.ru_idrss = r->ru_idrss;
182 r32.ru_isrss = r->ru_isrss;
183 r32.ru_minflt = r->ru_minflt;
184 r32.ru_majflt = r->ru_majflt;
185 r32.ru_nswap = r->ru_nswap;
186 r32.ru_inblock = r->ru_inblock;
187 r32.ru_oublock = r->ru_oublock;
188 r32.ru_msgsnd = r->ru_msgsnd;
189 r32.ru_msgrcv = r->ru_msgrcv;
190 r32.ru_nsignals = r->ru_nsignals;
191 r32.ru_nvcsw = r->ru_nvcsw;
192 r32.ru_nivcsw = r->ru_nivcsw;
193 if (copy_to_user(ru, &r32, sizeof(r32)))
194 return -EFAULT;
195 return 0;
196}
197
198static int compat_get_user_cpu_mask(compat_ulong_t __user *user_mask_ptr,
199 unsigned len, struct cpumask *new_mask)
200{
201 unsigned long *k;
202
203 if (len < cpumask_size())
204 memset(new_mask, 0, cpumask_size());
205 else if (len > cpumask_size())
206 len = cpumask_size();
207
208 k = cpumask_bits(new_mask);
209 return compat_get_bitmap(k, user_mask_ptr, len * 8);
210}
211
212COMPAT_SYSCALL_DEFINE3(sched_setaffinity, compat_pid_t, pid,
213 unsigned int, len,
214 compat_ulong_t __user *, user_mask_ptr)
215{
216 cpumask_var_t new_mask;
217 int retval;
218
219 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
220 return -ENOMEM;
221
222 retval = compat_get_user_cpu_mask(user_mask_ptr, len, new_mask);
223 if (retval)
224 goto out;
225
226 retval = sched_setaffinity(pid, new_mask);
227out:
228 free_cpumask_var(new_mask);
229 return retval;
230}
231
232COMPAT_SYSCALL_DEFINE3(sched_getaffinity, compat_pid_t, pid, unsigned int, len,
233 compat_ulong_t __user *, user_mask_ptr)
234{
235 int ret;
236 cpumask_var_t mask;
237
238 if ((len * BITS_PER_BYTE) < nr_cpu_ids)
239 return -EINVAL;
240 if (len & (sizeof(compat_ulong_t)-1))
241 return -EINVAL;
242
243 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
244 return -ENOMEM;
245
246 ret = sched_getaffinity(pid, mask);
247 if (ret == 0) {
248 unsigned int retlen = min(len, cpumask_size());
249
250 if (compat_put_bitmap(user_mask_ptr, cpumask_bits(mask), retlen * 8))
251 ret = -EFAULT;
252 else
253 ret = retlen;
254 }
255 free_cpumask_var(mask);
256
257 return ret;
258}
259
260/*
261 * We currently only need the following fields from the sigevent
262 * structure: sigev_value, sigev_signo, sig_notify and (sometimes
263 * sigev_notify_thread_id). The others are handled in user mode.
264 * We also assume that copying sigev_value.sival_int is sufficient
265 * to keep all the bits of sigev_value.sival_ptr intact.
266 */
267int get_compat_sigevent(struct sigevent *event,
268 const struct compat_sigevent __user *u_event)
269{
270 memset(event, 0, sizeof(*event));
271 return (!access_ok(u_event, sizeof(*u_event)) ||
272 __get_user(event->sigev_value.sival_int,
273 &u_event->sigev_value.sival_int) ||
274 __get_user(event->sigev_signo, &u_event->sigev_signo) ||
275 __get_user(event->sigev_notify, &u_event->sigev_notify) ||
276 __get_user(event->sigev_notify_thread_id,
277 &u_event->sigev_notify_thread_id))
278 ? -EFAULT : 0;
279}
280
281long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask,
282 unsigned long bitmap_size)
283{
284 unsigned long nr_compat_longs;
285
286 /* align bitmap up to nearest compat_long_t boundary */
287 bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
288 nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
289
290 if (!user_access_begin(umask, bitmap_size / 8))
291 return -EFAULT;
292
293 while (nr_compat_longs > 1) {
294 compat_ulong_t l1, l2;
295 unsafe_get_user(l1, umask++, Efault);
296 unsafe_get_user(l2, umask++, Efault);
297 *mask++ = ((unsigned long)l2 << BITS_PER_COMPAT_LONG) | l1;
298 nr_compat_longs -= 2;
299 }
300 if (nr_compat_longs)
301 unsafe_get_user(*mask, umask++, Efault);
302 user_access_end();
303 return 0;
304
305Efault:
306 user_access_end();
307 return -EFAULT;
308}
309
310long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
311 unsigned long bitmap_size)
312{
313 unsigned long nr_compat_longs;
314
315 /* align bitmap up to nearest compat_long_t boundary */
316 bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
317 nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
318
319 if (!user_access_begin(umask, bitmap_size / 8))
320 return -EFAULT;
321
322 while (nr_compat_longs > 1) {
323 unsigned long m = *mask++;
324 unsafe_put_user((compat_ulong_t)m, umask++, Efault);
325 unsafe_put_user(m >> BITS_PER_COMPAT_LONG, umask++, Efault);
326 nr_compat_longs -= 2;
327 }
328 if (nr_compat_longs)
329 unsafe_put_user((compat_ulong_t)*mask, umask++, Efault);
330 user_access_end();
331 return 0;
332Efault:
333 user_access_end();
334 return -EFAULT;
335}
336
337int
338get_compat_sigset(sigset_t *set, const compat_sigset_t __user *compat)
339{
340#ifdef __BIG_ENDIAN
341 compat_sigset_t v;
342 if (copy_from_user(&v, compat, sizeof(compat_sigset_t)))
343 return -EFAULT;
344 switch (_NSIG_WORDS) {
345 case 4: set->sig[3] = v.sig[6] | (((long)v.sig[7]) << 32 );
346 /* fall through */
347 case 3: set->sig[2] = v.sig[4] | (((long)v.sig[5]) << 32 );
348 /* fall through */
349 case 2: set->sig[1] = v.sig[2] | (((long)v.sig[3]) << 32 );
350 /* fall through */
351 case 1: set->sig[0] = v.sig[0] | (((long)v.sig[1]) << 32 );
352 }
353#else
354 if (copy_from_user(set, compat, sizeof(compat_sigset_t)))
355 return -EFAULT;
356#endif
357 return 0;
358}
359EXPORT_SYMBOL_GPL(get_compat_sigset);
360
361/*
362 * Allocate user-space memory for the duration of a single system call,
363 * in order to marshall parameters inside a compat thunk.
364 */
365void __user *compat_alloc_user_space(unsigned long len)
366{
367 void __user *ptr;
368
369 /* If len would occupy more than half of the entire compat space... */
370 if (unlikely(len > (((compat_uptr_t)~0) >> 1)))
371 return NULL;
372
373 ptr = arch_compat_alloc_user_space(len);
374
375 if (unlikely(!access_ok(ptr, len)))
376 return NULL;
377
378 return ptr;
379}
380EXPORT_SYMBOL_GPL(compat_alloc_user_space);