Merge tag 'sched-core-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6-microblaze.git] / kernel / compat.c
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
29 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
30
31 /*
32  * sys_sigprocmask SIG_SETMASK sets the first (compat) word of the
33  * blocked set of signals to the supplied signal set
34  */
35 static inline void compat_sig_setmask(sigset_t *blocked, compat_sigset_word set)
36 {
37         memcpy(blocked->sig, &set, sizeof(set));
38 }
39
40 COMPAT_SYSCALL_DEFINE3(sigprocmask, int, how,
41                        compat_old_sigset_t __user *, nset,
42                        compat_old_sigset_t __user *, oset)
43 {
44         old_sigset_t old_set, new_set;
45         sigset_t new_blocked;
46
47         old_set = current->blocked.sig[0];
48
49         if (nset) {
50                 if (get_user(new_set, nset))
51                         return -EFAULT;
52                 new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
53
54                 new_blocked = current->blocked;
55
56                 switch (how) {
57                 case SIG_BLOCK:
58                         sigaddsetmask(&new_blocked, new_set);
59                         break;
60                 case SIG_UNBLOCK:
61                         sigdelsetmask(&new_blocked, new_set);
62                         break;
63                 case SIG_SETMASK:
64                         compat_sig_setmask(&new_blocked, new_set);
65                         break;
66                 default:
67                         return -EINVAL;
68                 }
69
70                 set_current_blocked(&new_blocked);
71         }
72
73         if (oset) {
74                 if (put_user(old_set, oset))
75                         return -EFAULT;
76         }
77
78         return 0;
79 }
80
81 #endif
82
83 int put_compat_rusage(const struct rusage *r, struct compat_rusage __user *ru)
84 {
85         struct compat_rusage r32;
86         memset(&r32, 0, sizeof(r32));
87         r32.ru_utime.tv_sec = r->ru_utime.tv_sec;
88         r32.ru_utime.tv_usec = r->ru_utime.tv_usec;
89         r32.ru_stime.tv_sec = r->ru_stime.tv_sec;
90         r32.ru_stime.tv_usec = r->ru_stime.tv_usec;
91         r32.ru_maxrss = r->ru_maxrss;
92         r32.ru_ixrss = r->ru_ixrss;
93         r32.ru_idrss = r->ru_idrss;
94         r32.ru_isrss = r->ru_isrss;
95         r32.ru_minflt = r->ru_minflt;
96         r32.ru_majflt = r->ru_majflt;
97         r32.ru_nswap = r->ru_nswap;
98         r32.ru_inblock = r->ru_inblock;
99         r32.ru_oublock = r->ru_oublock;
100         r32.ru_msgsnd = r->ru_msgsnd;
101         r32.ru_msgrcv = r->ru_msgrcv;
102         r32.ru_nsignals = r->ru_nsignals;
103         r32.ru_nvcsw = r->ru_nvcsw;
104         r32.ru_nivcsw = r->ru_nivcsw;
105         if (copy_to_user(ru, &r32, sizeof(r32)))
106                 return -EFAULT;
107         return 0;
108 }
109
110 static int compat_get_user_cpu_mask(compat_ulong_t __user *user_mask_ptr,
111                                     unsigned len, struct cpumask *new_mask)
112 {
113         unsigned long *k;
114
115         if (len < cpumask_size())
116                 memset(new_mask, 0, cpumask_size());
117         else if (len > cpumask_size())
118                 len = cpumask_size();
119
120         k = cpumask_bits(new_mask);
121         return compat_get_bitmap(k, user_mask_ptr, len * 8);
122 }
123
124 COMPAT_SYSCALL_DEFINE3(sched_setaffinity, compat_pid_t, pid,
125                        unsigned int, len,
126                        compat_ulong_t __user *, user_mask_ptr)
127 {
128         cpumask_var_t new_mask;
129         int retval;
130
131         if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
132                 return -ENOMEM;
133
134         retval = compat_get_user_cpu_mask(user_mask_ptr, len, new_mask);
135         if (retval)
136                 goto out;
137
138         retval = sched_setaffinity(pid, new_mask);
139 out:
140         free_cpumask_var(new_mask);
141         return retval;
142 }
143
144 COMPAT_SYSCALL_DEFINE3(sched_getaffinity, compat_pid_t,  pid, unsigned int, len,
145                        compat_ulong_t __user *, user_mask_ptr)
146 {
147         int ret;
148         cpumask_var_t mask;
149
150         if ((len * BITS_PER_BYTE) < nr_cpu_ids)
151                 return -EINVAL;
152         if (len & (sizeof(compat_ulong_t)-1))
153                 return -EINVAL;
154
155         if (!alloc_cpumask_var(&mask, GFP_KERNEL))
156                 return -ENOMEM;
157
158         ret = sched_getaffinity(pid, mask);
159         if (ret == 0) {
160                 unsigned int retlen = min(len, cpumask_size());
161
162                 if (compat_put_bitmap(user_mask_ptr, cpumask_bits(mask), retlen * 8))
163                         ret = -EFAULT;
164                 else
165                         ret = retlen;
166         }
167         free_cpumask_var(mask);
168
169         return ret;
170 }
171
172 /*
173  * We currently only need the following fields from the sigevent
174  * structure: sigev_value, sigev_signo, sig_notify and (sometimes
175  * sigev_notify_thread_id).  The others are handled in user mode.
176  * We also assume that copying sigev_value.sival_int is sufficient
177  * to keep all the bits of sigev_value.sival_ptr intact.
178  */
179 int get_compat_sigevent(struct sigevent *event,
180                 const struct compat_sigevent __user *u_event)
181 {
182         memset(event, 0, sizeof(*event));
183         return (!access_ok(u_event, sizeof(*u_event)) ||
184                 __get_user(event->sigev_value.sival_int,
185                         &u_event->sigev_value.sival_int) ||
186                 __get_user(event->sigev_signo, &u_event->sigev_signo) ||
187                 __get_user(event->sigev_notify, &u_event->sigev_notify) ||
188                 __get_user(event->sigev_notify_thread_id,
189                         &u_event->sigev_notify_thread_id))
190                 ? -EFAULT : 0;
191 }
192
193 long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask,
194                        unsigned long bitmap_size)
195 {
196         unsigned long nr_compat_longs;
197
198         /* align bitmap up to nearest compat_long_t boundary */
199         bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
200         nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
201
202         if (!user_read_access_begin(umask, bitmap_size / 8))
203                 return -EFAULT;
204
205         while (nr_compat_longs > 1) {
206                 compat_ulong_t l1, l2;
207                 unsafe_get_user(l1, umask++, Efault);
208                 unsafe_get_user(l2, umask++, Efault);
209                 *mask++ = ((unsigned long)l2 << BITS_PER_COMPAT_LONG) | l1;
210                 nr_compat_longs -= 2;
211         }
212         if (nr_compat_longs)
213                 unsafe_get_user(*mask, umask++, Efault);
214         user_read_access_end();
215         return 0;
216
217 Efault:
218         user_read_access_end();
219         return -EFAULT;
220 }
221
222 long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
223                        unsigned long bitmap_size)
224 {
225         unsigned long nr_compat_longs;
226
227         /* align bitmap up to nearest compat_long_t boundary */
228         bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
229         nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
230
231         if (!user_write_access_begin(umask, bitmap_size / 8))
232                 return -EFAULT;
233
234         while (nr_compat_longs > 1) {
235                 unsigned long m = *mask++;
236                 unsafe_put_user((compat_ulong_t)m, umask++, Efault);
237                 unsafe_put_user(m >> BITS_PER_COMPAT_LONG, umask++, Efault);
238                 nr_compat_longs -= 2;
239         }
240         if (nr_compat_longs)
241                 unsafe_put_user((compat_ulong_t)*mask, umask++, Efault);
242         user_write_access_end();
243         return 0;
244 Efault:
245         user_write_access_end();
246         return -EFAULT;
247 }
248
249 int
250 get_compat_sigset(sigset_t *set, const compat_sigset_t __user *compat)
251 {
252 #ifdef __BIG_ENDIAN
253         compat_sigset_t v;
254         if (copy_from_user(&v, compat, sizeof(compat_sigset_t)))
255                 return -EFAULT;
256         switch (_NSIG_WORDS) {
257         case 4: set->sig[3] = v.sig[6] | (((long)v.sig[7]) << 32 );
258                 fallthrough;
259         case 3: set->sig[2] = v.sig[4] | (((long)v.sig[5]) << 32 );
260                 fallthrough;
261         case 2: set->sig[1] = v.sig[2] | (((long)v.sig[3]) << 32 );
262                 fallthrough;
263         case 1: set->sig[0] = v.sig[0] | (((long)v.sig[1]) << 32 );
264         }
265 #else
266         if (copy_from_user(set, compat, sizeof(compat_sigset_t)))
267                 return -EFAULT;
268 #endif
269         return 0;
270 }
271 EXPORT_SYMBOL_GPL(get_compat_sigset);
272
273 /*
274  * Allocate user-space memory for the duration of a single system call,
275  * in order to marshall parameters inside a compat thunk.
276  */
277 void __user *compat_alloc_user_space(unsigned long len)
278 {
279         void __user *ptr;
280
281         /* If len would occupy more than half of the entire compat space... */
282         if (unlikely(len > (((compat_uptr_t)~0) >> 1)))
283                 return NULL;
284
285         ptr = arch_compat_alloc_user_space(len);
286
287         if (unlikely(!access_ok(ptr, len)))
288                 return NULL;
289
290         return ptr;
291 }
292 EXPORT_SYMBOL_GPL(compat_alloc_user_space);