// SPDX-License-Identifier: GPL-2.0-only /* * linux/kernel/compat.c * * Kernel compatibililty routines for e.g. 32 bit syscall support * on 64 bit kernels. * * Copyright (C) 2002-2003 Stephen Rothwell, IBM Corporation */ #include <linux/linkage.h> #include <linux/compat.h> #include <linux/errno.h> #include <linux/time.h> #include <linux/signal.h> #include <linux/sched.h> /* for MAX_SCHEDULE_TIMEOUT */ #include <linux/syscalls.h> #include <linux/unistd.h> #include <linux/security.h> #include <linux/export.h> #include <linux/migrate.h> #include <linux/posix-timers.h> #include <linux/times.h> #include <linux/ptrace.h> #include <linux/gfp.h> #include <linux/uaccess.h> #ifdef __ARCH_WANT_SYS_SIGPROCMASK /* * sys_sigprocmask SIG_SETMASK sets the first (compat) word of the * blocked set of signals to the supplied signal set */ static inline void compat_sig_setmask(sigset_t *blocked, compat_sigset_word set) { memcpy(blocked->sig, &set, sizeof(set)); } COMPAT_SYSCALL_DEFINE3(sigprocmask, int, how, compat_old_sigset_t __user *, nset, compat_old_sigset_t __user *, oset) { old_sigset_t old_set, new_set; sigset_t new_blocked; old_set = current->blocked.sig[0]; if (nset) { if (get_user(new_set, nset)) return -EFAULT; new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP)); new_blocked = current->blocked; switch (how) { case SIG_BLOCK: sigaddsetmask(&new_blocked, new_set); break; case SIG_UNBLOCK: sigdelsetmask(&new_blocked, new_set); break; case SIG_SETMASK: compat_sig_setmask(&new_blocked, new_set); break; default: return -EINVAL; } set_current_blocked(&new_blocked); } if (oset) { if (put_user(old_set, oset)) return -EFAULT; } return 0; } #endif int put_compat_rusage(const struct rusage *r, struct compat_rusage __user *ru) { struct compat_rusage r32; memset(&r32, 0, sizeof(r32)); r32.ru_utime.tv_sec = r->ru_utime.tv_sec; r32.ru_utime.tv_usec = r->ru_utime.tv_usec; r32.ru_stime.tv_sec = r->ru_stime.tv_sec; r32.ru_stime.tv_usec = r->ru_stime.tv_usec; r32.ru_maxrss = r->ru_maxrss; r32.ru_ixrss = r->ru_ixrss; r32.ru_idrss = r->ru_idrss; r32.ru_isrss = r->ru_isrss; r32.ru_minflt = r->ru_minflt; r32.ru_majflt = r->ru_majflt; r32.ru_nswap = r->ru_nswap; r32.ru_inblock = r->ru_inblock; r32.ru_oublock = r->ru_oublock; r32.ru_msgsnd = r->ru_msgsnd; r32.ru_msgrcv = r->ru_msgrcv; r32.ru_nsignals = r->ru_nsignals; r32.ru_nvcsw = r->ru_nvcsw; r32.ru_nivcsw = r->ru_nivcsw; if (copy_to_user(ru, &r32, sizeof(r32))) return -EFAULT; return 0; } static int compat_get_user_cpu_mask(compat_ulong_t __user *user_mask_ptr, unsigned len, struct cpumask *new_mask) { unsigned long *k; if (len < cpumask_size()) memset(new_mask, 0, cpumask_size()); else if (len > cpumask_size()) len = cpumask_size(); k = cpumask_bits(new_mask); return compat_get_bitmap(k, user_mask_ptr, len * 8); } COMPAT_SYSCALL_DEFINE3(sched_setaffinity, compat_pid_t, pid, unsigned int, len, compat_ulong_t __user *, user_mask_ptr) { cpumask_var_t new_mask; int retval; if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) return -ENOMEM; retval = compat_get_user_cpu_mask(user_mask_ptr, len, new_mask); if (retval) goto out; retval = sched_setaffinity(pid, new_mask); out: free_cpumask_var(new_mask); return retval; } COMPAT_SYSCALL_DEFINE3(sched_getaffinity, compat_pid_t, pid, unsigned int, len, compat_ulong_t __user *, user_mask_ptr) { int ret; cpumask_var_t mask; if ((len * BITS_PER_BYTE) < nr_cpu_ids) return -EINVAL; if (len & (sizeof(compat_ulong_t)-1)) return -EINVAL; if (!alloc_cpumask_var(&mask, GFP_KERNEL)) return -ENOMEM; ret = sched_getaffinity(pid, mask); if (ret == 0) { unsigned int retlen = min(len, cpumask_size()); if (compat_put_bitmap(user_mask_ptr, cpumask_bits(mask), retlen * 8)) ret = -EFAULT; else ret = retlen; } free_cpumask_var(mask); return ret; } /* * We currently only need the following fields from the sigevent * structure: sigev_value, sigev_signo, sig_notify and (sometimes * sigev_notify_thread_id). The others are handled in user mode. * We also assume that copying sigev_value.sival_int is sufficient * to keep all the bits of sigev_value.sival_ptr intact. */ int get_compat_sigevent(struct sigevent *event, const struct compat_sigevent __user *u_event) { memset(event, 0, sizeof(*event)); return (!access_ok(u_event, sizeof(*u_event)) || __get_user(event->sigev_value.sival_int, &u_event->sigev_value.sival_int) || __get_user(event->sigev_signo, &u_event->sigev_signo) || __get_user(event->sigev_notify, &u_event->sigev_notify) || __get_user(event->sigev_notify_thread_id, &u_event->sigev_notify_thread_id)) ? -EFAULT : 0; } long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask, unsigned long bitmap_size) { unsigned long nr_compat_longs; /* align bitmap up to nearest compat_long_t boundary */ bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG); nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size); if (!user_read_access_begin(umask, bitmap_size / 8)) return -EFAULT; while (nr_compat_longs > 1) { compat_ulong_t l1, l2; unsafe_get_user(l1, umask++, Efault); unsafe_get_user(l2, umask++, Efault); *mask++ = ((unsigned long)l2 << BITS_PER_COMPAT_LONG) | l1; nr_compat_longs -= 2; } if (nr_compat_longs) unsafe_get_user(*mask, umask++, Efault); user_read_access_end(); return 0; Efault: user_read_access_end(); return -EFAULT; } long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask, unsigned long bitmap_size) { unsigned long nr_compat_longs; /* align bitmap up to nearest compat_long_t boundary */ bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG); nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size); if (!user_write_access_begin(umask, bitmap_size / 8)) return -EFAULT; while (nr_compat_longs > 1) { unsigned long m = *mask++; unsafe_put_user((compat_ulong_t)m, umask++, Efault); unsafe_put_user(m >> BITS_PER_COMPAT_LONG, umask++, Efault); nr_compat_longs -= 2; } if (nr_compat_longs) unsafe_put_user((compat_ulong_t)*mask, umask++, Efault); user_write_access_end(); return 0; Efault: user_write_access_end(); return -EFAULT; } int get_compat_sigset(sigset_t *set, const compat_sigset_t __user *compat) { #ifdef __BIG_ENDIAN compat_sigset_t v; if (copy_from_user(&v, compat, sizeof(compat_sigset_t))) return -EFAULT; switch (_NSIG_WORDS) { case 4: set->sig[3] = v.sig[6] | (((long)v.sig[7]) << 32 ); fallthrough; case 3: set->sig[2] = v.sig[4] | (((long)v.sig[5]) << 32 ); fallthrough; case 2: set->sig[1] = v.sig[2] | (((long)v.sig[3]) << 32 ); fallthrough; case 1: set->sig[0] = v.sig[0] | (((long)v.sig[1]) << 32 ); } #else if (copy_from_user(set, compat, sizeof(compat_sigset_t))) return -EFAULT; #endif return 0; } EXPORT_SYMBOL_GPL(get_compat_sigset); /* * Allocate user-space memory for the duration of a single system call, * in order to marshall parameters inside a compat thunk. */ void __user *compat_alloc_user_space(unsigned long len) { void __user *ptr; /* If len would occupy more than half of the entire compat space... */ if (unlikely(len > (((compat_uptr_t)~0) >> 1))) return NULL; ptr = arch_compat_alloc_user_space(len); if (unlikely(!access_ok(ptr, len))) return NULL; return ptr; } EXPORT_SYMBOL_GPL(compat_alloc_user_space);