1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/kernel/compat.c
5 * Kernel compatibililty routines for e.g. 32 bit syscall support
8 * Copyright (C) 2002-2003 Stephen Rothwell, IBM Corporation
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>
27 #include <linux/uaccess.h>
29 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
32 * sys_sigprocmask SIG_SETMASK sets the first (compat) word of the
33 * blocked set of signals to the supplied signal set
35 static inline void compat_sig_setmask(sigset_t *blocked, compat_sigset_word set)
37 memcpy(blocked->sig, &set, sizeof(set));
40 COMPAT_SYSCALL_DEFINE3(sigprocmask, int, how,
41 compat_old_sigset_t __user *, nset,
42 compat_old_sigset_t __user *, oset)
44 old_sigset_t old_set, new_set;
47 old_set = current->blocked.sig[0];
50 if (get_user(new_set, nset))
52 new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
54 new_blocked = current->blocked;
58 sigaddsetmask(&new_blocked, new_set);
61 sigdelsetmask(&new_blocked, new_set);
64 compat_sig_setmask(&new_blocked, new_set);
70 set_current_blocked(&new_blocked);
74 if (put_user(old_set, oset))
83 int put_compat_rusage(const struct rusage *r, struct compat_rusage __user *ru)
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)))
110 static int compat_get_user_cpu_mask(compat_ulong_t __user *user_mask_ptr,
111 unsigned len, struct cpumask *new_mask)
115 if (len < cpumask_size())
116 memset(new_mask, 0, cpumask_size());
117 else if (len > cpumask_size())
118 len = cpumask_size();
120 k = cpumask_bits(new_mask);
121 return compat_get_bitmap(k, user_mask_ptr, len * 8);
124 COMPAT_SYSCALL_DEFINE3(sched_setaffinity, compat_pid_t, pid,
126 compat_ulong_t __user *, user_mask_ptr)
128 cpumask_var_t new_mask;
131 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
134 retval = compat_get_user_cpu_mask(user_mask_ptr, len, new_mask);
138 retval = sched_setaffinity(pid, new_mask);
140 free_cpumask_var(new_mask);
144 COMPAT_SYSCALL_DEFINE3(sched_getaffinity, compat_pid_t, pid, unsigned int, len,
145 compat_ulong_t __user *, user_mask_ptr)
150 if ((len * BITS_PER_BYTE) < nr_cpu_ids)
152 if (len & (sizeof(compat_ulong_t)-1))
155 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
158 ret = sched_getaffinity(pid, mask);
160 unsigned int retlen = min(len, cpumask_size());
162 if (compat_put_bitmap(user_mask_ptr, cpumask_bits(mask), retlen * 8))
167 free_cpumask_var(mask);
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.
179 int get_compat_sigevent(struct sigevent *event,
180 const struct compat_sigevent __user *u_event)
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))
193 long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask,
194 unsigned long bitmap_size)
196 unsigned long nr_compat_longs;
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);
202 if (!user_read_access_begin(umask, bitmap_size / 8))
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;
213 unsafe_get_user(*mask, umask++, Efault);
214 user_read_access_end();
218 user_read_access_end();
222 long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
223 unsigned long bitmap_size)
225 unsigned long nr_compat_longs;
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);
231 if (!user_write_access_begin(umask, bitmap_size / 8))
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;
241 unsafe_put_user((compat_ulong_t)*mask, umask++, Efault);
242 user_write_access_end();
245 user_write_access_end();
250 get_compat_sigset(sigset_t *set, const compat_sigset_t __user *compat)
254 if (copy_from_user(&v, compat, sizeof(compat_sigset_t)))
256 switch (_NSIG_WORDS) {
257 case 4: set->sig[3] = v.sig[6] | (((long)v.sig[7]) << 32 );
259 case 3: set->sig[2] = v.sig[4] | (((long)v.sig[5]) << 32 );
261 case 2: set->sig[1] = v.sig[2] | (((long)v.sig[3]) << 32 );
263 case 1: set->sig[0] = v.sig[0] | (((long)v.sig[1]) << 32 );
266 if (copy_from_user(set, compat, sizeof(compat_sigset_t)))
271 EXPORT_SYMBOL_GPL(get_compat_sigset);
274 * Allocate user-space memory for the duration of a single system call,
275 * in order to marshall parameters inside a compat thunk.
277 void __user *compat_alloc_user_space(unsigned long len)
281 /* If len would occupy more than half of the entire compat space... */
282 if (unlikely(len > (((compat_uptr_t)~0) >> 1)))
285 ptr = arch_compat_alloc_user_space(len);
287 if (unlikely(!access_ok(ptr, len)))
292 EXPORT_SYMBOL_GPL(compat_alloc_user_space);