Line data Source code
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 0 : static inline void compat_sig_setmask(sigset_t *blocked, compat_sigset_word set)
36 : {
37 0 : memcpy(blocked->sig, &set, sizeof(set));
38 0 : }
39 :
40 0 : COMPAT_SYSCALL_DEFINE3(sigprocmask, int, how,
41 : compat_old_sigset_t __user *, nset,
42 : compat_old_sigset_t __user *, oset)
43 : {
44 0 : old_sigset_t old_set, new_set;
45 0 : sigset_t new_blocked;
46 :
47 0 : old_set = current->blocked.sig[0];
48 :
49 0 : if (nset) {
50 0 : if (get_user(new_set, nset))
51 : return -EFAULT;
52 0 : new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
53 :
54 0 : new_blocked = current->blocked;
55 :
56 0 : switch (how) {
57 : case SIG_BLOCK:
58 0 : sigaddsetmask(&new_blocked, new_set);
59 : break;
60 : case SIG_UNBLOCK:
61 0 : sigdelsetmask(&new_blocked, new_set);
62 : break;
63 0 : case SIG_SETMASK:
64 0 : compat_sig_setmask(&new_blocked, new_set);
65 : break;
66 : default:
67 : return -EINVAL;
68 : }
69 :
70 0 : set_current_blocked(&new_blocked);
71 : }
72 :
73 0 : if (oset) {
74 0 : if (put_user(old_set, oset))
75 0 : return -EFAULT;
76 : }
77 :
78 : return 0;
79 : }
80 :
81 : #endif
82 :
83 0 : int put_compat_rusage(const struct rusage *r, struct compat_rusage __user *ru)
84 : {
85 0 : struct compat_rusage r32;
86 0 : memset(&r32, 0, sizeof(r32));
87 0 : r32.ru_utime.tv_sec = r->ru_utime.tv_sec;
88 0 : r32.ru_utime.tv_usec = r->ru_utime.tv_usec;
89 0 : r32.ru_stime.tv_sec = r->ru_stime.tv_sec;
90 0 : r32.ru_stime.tv_usec = r->ru_stime.tv_usec;
91 0 : r32.ru_maxrss = r->ru_maxrss;
92 0 : r32.ru_ixrss = r->ru_ixrss;
93 0 : r32.ru_idrss = r->ru_idrss;
94 0 : r32.ru_isrss = r->ru_isrss;
95 0 : r32.ru_minflt = r->ru_minflt;
96 0 : r32.ru_majflt = r->ru_majflt;
97 0 : r32.ru_nswap = r->ru_nswap;
98 0 : r32.ru_inblock = r->ru_inblock;
99 0 : r32.ru_oublock = r->ru_oublock;
100 0 : r32.ru_msgsnd = r->ru_msgsnd;
101 0 : r32.ru_msgrcv = r->ru_msgrcv;
102 0 : r32.ru_nsignals = r->ru_nsignals;
103 0 : r32.ru_nvcsw = r->ru_nvcsw;
104 0 : r32.ru_nivcsw = r->ru_nivcsw;
105 0 : if (copy_to_user(ru, &r32, sizeof(r32)))
106 0 : return -EFAULT;
107 : return 0;
108 : }
109 :
110 0 : static int compat_get_user_cpu_mask(compat_ulong_t __user *user_mask_ptr,
111 : unsigned len, struct cpumask *new_mask)
112 : {
113 0 : unsigned long *k;
114 :
115 0 : if (len < cpumask_size())
116 0 : memset(new_mask, 0, cpumask_size());
117 0 : else if (len > cpumask_size())
118 0 : len = cpumask_size();
119 :
120 0 : k = cpumask_bits(new_mask);
121 0 : return compat_get_bitmap(k, user_mask_ptr, len * 8);
122 : }
123 :
124 0 : COMPAT_SYSCALL_DEFINE3(sched_setaffinity, compat_pid_t, pid,
125 : unsigned int, len,
126 : compat_ulong_t __user *, user_mask_ptr)
127 : {
128 0 : cpumask_var_t new_mask;
129 0 : int retval;
130 :
131 0 : if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
132 : return -ENOMEM;
133 :
134 0 : retval = compat_get_user_cpu_mask(user_mask_ptr, len, new_mask);
135 0 : if (retval)
136 0 : goto out;
137 :
138 0 : retval = sched_setaffinity(pid, new_mask);
139 0 : out:
140 0 : free_cpumask_var(new_mask);
141 0 : return retval;
142 : }
143 :
144 0 : COMPAT_SYSCALL_DEFINE3(sched_getaffinity, compat_pid_t, pid, unsigned int, len,
145 : compat_ulong_t __user *, user_mask_ptr)
146 : {
147 0 : int ret;
148 0 : cpumask_var_t mask;
149 :
150 0 : if ((len * BITS_PER_BYTE) < nr_cpu_ids)
151 : return -EINVAL;
152 0 : if (len & (sizeof(compat_ulong_t)-1))
153 : return -EINVAL;
154 :
155 0 : if (!alloc_cpumask_var(&mask, GFP_KERNEL))
156 : return -ENOMEM;
157 :
158 0 : ret = sched_getaffinity(pid, mask);
159 0 : if (ret == 0) {
160 0 : unsigned int retlen = min(len, cpumask_size());
161 :
162 0 : if (compat_put_bitmap(user_mask_ptr, cpumask_bits(mask), retlen * 8))
163 : ret = -EFAULT;
164 : else
165 0 : ret = retlen;
166 : }
167 0 : free_cpumask_var(mask);
168 :
169 0 : 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 0 : int get_compat_sigevent(struct sigevent *event,
180 : const struct compat_sigevent __user *u_event)
181 : {
182 0 : memset(event, 0, sizeof(*event));
183 0 : return (!access_ok(u_event, sizeof(*u_event)) ||
184 0 : __get_user(event->sigev_value.sival_int,
185 0 : &u_event->sigev_value.sival_int) ||
186 0 : __get_user(event->sigev_signo, &u_event->sigev_signo) ||
187 0 : __get_user(event->sigev_notify, &u_event->sigev_notify) ||
188 0 : __get_user(event->sigev_notify_thread_id,
189 : &u_event->sigev_notify_thread_id))
190 0 : ? -EFAULT : 0;
191 : }
192 :
193 0 : long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask,
194 : unsigned long bitmap_size)
195 : {
196 0 : unsigned long nr_compat_longs;
197 :
198 : /* align bitmap up to nearest compat_long_t boundary */
199 0 : bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
200 0 : nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
201 :
202 0 : if (!user_read_access_begin(umask, bitmap_size / 8))
203 : return -EFAULT;
204 :
205 0 : while (nr_compat_longs > 1) {
206 0 : compat_ulong_t l1, l2;
207 0 : unsafe_get_user(l1, umask++, Efault);
208 0 : unsafe_get_user(l2, umask++, Efault);
209 0 : *mask++ = ((unsigned long)l2 << BITS_PER_COMPAT_LONG) | l1;
210 0 : nr_compat_longs -= 2;
211 : }
212 0 : if (nr_compat_longs)
213 0 : 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 0 : long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
223 : unsigned long bitmap_size)
224 : {
225 0 : unsigned long nr_compat_longs;
226 :
227 : /* align bitmap up to nearest compat_long_t boundary */
228 0 : bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
229 0 : nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
230 :
231 0 : if (!user_write_access_begin(umask, bitmap_size / 8))
232 : return -EFAULT;
233 :
234 0 : while (nr_compat_longs > 1) {
235 0 : unsigned long m = *mask++;
236 0 : unsafe_put_user((compat_ulong_t)m, umask++, Efault);
237 0 : unsafe_put_user(m >> BITS_PER_COMPAT_LONG, umask++, Efault);
238 0 : nr_compat_longs -= 2;
239 : }
240 0 : if (nr_compat_longs)
241 0 : unsafe_put_user((compat_ulong_t)*mask, umask++, Efault);
242 : user_write_access_end();
243 : return 0;
244 0 : Efault:
245 : user_write_access_end();
246 : return -EFAULT;
247 : }
248 :
249 : int
250 0 : 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 0 : if (copy_from_user(set, compat, sizeof(compat_sigset_t)))
267 0 : 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 0 : void __user *compat_alloc_user_space(unsigned long len)
278 : {
279 0 : void __user *ptr;
280 :
281 : /* If len would occupy more than half of the entire compat space... */
282 0 : if (unlikely(len > (((compat_uptr_t)~0) >> 1)))
283 : return NULL;
284 :
285 0 : ptr = arch_compat_alloc_user_space(len);
286 :
287 0 : if (unlikely(!access_ok(ptr, len)))
288 0 : return NULL;
289 :
290 : return ptr;
291 : }
292 : EXPORT_SYMBOL_GPL(compat_alloc_user_space);
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