projects/linux·blob v5.16 · refs

271 lines · 6.8 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
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 */
35static inline void compat_sig_setmask(sigset_t *blocked, compat_sigset_word set)
36{
37 memcpy(blocked->sig, &set, sizeof(set));
38}
39
40COMPAT_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
83int 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
110static 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
124COMPAT_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);
139out:
140 free_cpumask_var(new_mask);
141 return retval;
142}
143
144COMPAT_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 */
179int 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
193long 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
217Efault:
218 user_read_access_end();
219 return -EFAULT;
220}
221
222long 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;
244Efault:
245 user_write_access_end();
246 return -EFAULT;
247}
248
249int
250get_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}
271EXPORT_SYMBOL_GPL(get_compat_sigset);