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); 293