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 static 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 36 static 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 43 static 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 50 static 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 57 int 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 } 64 EXPORT_SYMBOL_GPL(compat_get_timeval); 65 66 int 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 } 73 EXPORT_SYMBOL_GPL(compat_put_timeval); 74 75 int 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 } 82 EXPORT_SYMBOL_GPL(compat_get_timespec); 83 84 int 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 } 91 EXPORT_SYMBOL_GPL(compat_put_timespec); 92 93 int 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 } 105 106 int 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 */ 123 static inline void compat_sig_setmask(sigset_t *blocked, compat_sigset_word set) 124 { 125 memcpy(blocked->sig, &set, sizeof(set)); 126 } 127 128 COMPAT_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 170 171 int 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 } 197 198 static 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 } 211 212 COMPAT_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); 227 out: 228 free_cpumask_var(new_mask); 229 return retval; 230 } 231 232 COMPAT_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 */ 267 int 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 } 280 281 long 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; 304 305 Efault: 306 user_access_end(); 307 return -EFAULT; 308 } 309 310 long 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; 332 Efault: 333 user_access_end(); 334 return -EFAULT; 335 } 336 337 int 338 get_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 } 359 EXPORT_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 */ 365 void __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 } 380 EXPORT_SYMBOL_GPL(compat_alloc_user_space); 381