linux/kernel/compat.c
Arnd Bergmann 9afc5eee65 y2038: globally rename compat_time to old_time32
Christoph Hellwig suggested a slightly different path for handling
backwards compatibility with the 32-bit time_t based system calls:

Rather than simply reusing the compat_sys_* entry points on 32-bit
architectures unchanged, we get rid of those entry points and the
compat_time types by renaming them to something that makes more sense
on 32-bit architectures (which don't have a compat mode otherwise),
and then share the entry points under the new name with the 64-bit
architectures that use them for implementing the compatibility.

The following types and interfaces are renamed here, and moved
from linux/compat_time.h to linux/time32.h:

old				new
---				---
compat_time_t			old_time32_t
struct compat_timeval		struct old_timeval32
struct compat_timespec		struct old_timespec32
struct compat_itimerspec	struct old_itimerspec32
ns_to_compat_timeval()		ns_to_old_timeval32()
get_compat_itimerspec64()	get_old_itimerspec32()
put_compat_itimerspec64()	put_old_itimerspec32()
compat_get_timespec64()		get_old_timespec32()
compat_put_timespec64()		put_old_timespec32()

As we already have aliases in place, this patch addresses only the
instances that are relevant to the system call interface in particular,
not those that occur in device drivers and other modules. Those
will get handled separately, while providing the 64-bit version
of the respective interfaces.

I'm not renaming the timex, rusage and itimerval structures, as we are
still debating what the new interface will look like, and whether we
will need a replacement at all.

This also doesn't change the names of the syscall entry points, which can
be done more easily when we actually switch over the 32-bit architectures
to use them, at that point we need to change COMPAT_SYSCALL_DEFINEx to
SYSCALL_DEFINEx with a new name, e.g. with a _time32 suffix.

Suggested-by: Christoph Hellwig <hch@infradead.org>
Link: https://lore.kernel.org/lkml/20180705222110.GA5698@infradead.org/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2018-08-27 14:48:48 +02:00

447 lines
12 KiB
C

/*
* 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
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#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/timex.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>
int compat_get_timex(struct timex *txc, const struct compat_timex __user *utp)
{
struct compat_timex tx32;
memset(txc, 0, sizeof(struct timex));
if (copy_from_user(&tx32, utp, sizeof(struct compat_timex)))
return -EFAULT;
txc->modes = tx32.modes;
txc->offset = tx32.offset;
txc->freq = tx32.freq;
txc->maxerror = tx32.maxerror;
txc->esterror = tx32.esterror;
txc->status = tx32.status;
txc->constant = tx32.constant;
txc->precision = tx32.precision;
txc->tolerance = tx32.tolerance;
txc->time.tv_sec = tx32.time.tv_sec;
txc->time.tv_usec = tx32.time.tv_usec;
txc->tick = tx32.tick;
txc->ppsfreq = tx32.ppsfreq;
txc->jitter = tx32.jitter;
txc->shift = tx32.shift;
txc->stabil = tx32.stabil;
txc->jitcnt = tx32.jitcnt;
txc->calcnt = tx32.calcnt;
txc->errcnt = tx32.errcnt;
txc->stbcnt = tx32.stbcnt;
return 0;
}
int compat_put_timex(struct compat_timex __user *utp, const struct timex *txc)
{
struct compat_timex tx32;
memset(&tx32, 0, sizeof(struct compat_timex));
tx32.modes = txc->modes;
tx32.offset = txc->offset;
tx32.freq = txc->freq;
tx32.maxerror = txc->maxerror;
tx32.esterror = txc->esterror;
tx32.status = txc->status;
tx32.constant = txc->constant;
tx32.precision = txc->precision;
tx32.tolerance = txc->tolerance;
tx32.time.tv_sec = txc->time.tv_sec;
tx32.time.tv_usec = txc->time.tv_usec;
tx32.tick = txc->tick;
tx32.ppsfreq = txc->ppsfreq;
tx32.jitter = txc->jitter;
tx32.shift = txc->shift;
tx32.stabil = txc->stabil;
tx32.jitcnt = txc->jitcnt;
tx32.calcnt = txc->calcnt;
tx32.errcnt = txc->errcnt;
tx32.stbcnt = txc->stbcnt;
tx32.tai = txc->tai;
if (copy_to_user(utp, &tx32, sizeof(struct compat_timex)))
return -EFAULT;
return 0;
}
static int __compat_get_timeval(struct timeval *tv, const struct old_timeval32 __user *ctv)
{
return (!access_ok(VERIFY_READ, ctv, sizeof(*ctv)) ||
__get_user(tv->tv_sec, &ctv->tv_sec) ||
__get_user(tv->tv_usec, &ctv->tv_usec)) ? -EFAULT : 0;
}
static int __compat_put_timeval(const struct timeval *tv, struct old_timeval32 __user *ctv)
{
return (!access_ok(VERIFY_WRITE, ctv, sizeof(*ctv)) ||
__put_user(tv->tv_sec, &ctv->tv_sec) ||
__put_user(tv->tv_usec, &ctv->tv_usec)) ? -EFAULT : 0;
}
static int __compat_get_timespec(struct timespec *ts, const struct old_timespec32 __user *cts)
{
return (!access_ok(VERIFY_READ, cts, sizeof(*cts)) ||
__get_user(ts->tv_sec, &cts->tv_sec) ||
__get_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
}
static int __compat_put_timespec(const struct timespec *ts, struct old_timespec32 __user *cts)
{
return (!access_ok(VERIFY_WRITE, cts, sizeof(*cts)) ||
__put_user(ts->tv_sec, &cts->tv_sec) ||
__put_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
}
int compat_get_timeval(struct timeval *tv, const void __user *utv)
{
if (COMPAT_USE_64BIT_TIME)
return copy_from_user(tv, utv, sizeof(*tv)) ? -EFAULT : 0;
else
return __compat_get_timeval(tv, utv);
}
EXPORT_SYMBOL_GPL(compat_get_timeval);
int compat_put_timeval(const struct timeval *tv, void __user *utv)
{
if (COMPAT_USE_64BIT_TIME)
return copy_to_user(utv, tv, sizeof(*tv)) ? -EFAULT : 0;
else
return __compat_put_timeval(tv, utv);
}
EXPORT_SYMBOL_GPL(compat_put_timeval);
int compat_get_timespec(struct timespec *ts, const void __user *uts)
{
if (COMPAT_USE_64BIT_TIME)
return copy_from_user(ts, uts, sizeof(*ts)) ? -EFAULT : 0;
else
return __compat_get_timespec(ts, uts);
}
EXPORT_SYMBOL_GPL(compat_get_timespec);
int compat_put_timespec(const struct timespec *ts, void __user *uts)
{
if (COMPAT_USE_64BIT_TIME)
return copy_to_user(uts, ts, sizeof(*ts)) ? -EFAULT : 0;
else
return __compat_put_timespec(ts, uts);
}
EXPORT_SYMBOL_GPL(compat_put_timespec);
int get_compat_itimerval(struct itimerval *o, const struct compat_itimerval __user *i)
{
struct compat_itimerval v32;
if (copy_from_user(&v32, i, sizeof(struct compat_itimerval)))
return -EFAULT;
o->it_interval.tv_sec = v32.it_interval.tv_sec;
o->it_interval.tv_usec = v32.it_interval.tv_usec;
o->it_value.tv_sec = v32.it_value.tv_sec;
o->it_value.tv_usec = v32.it_value.tv_usec;
return 0;
}
int put_compat_itimerval(struct compat_itimerval __user *o, const struct itimerval *i)
{
struct compat_itimerval v32;
v32.it_interval.tv_sec = i->it_interval.tv_sec;
v32.it_interval.tv_usec = i->it_interval.tv_usec;
v32.it_value.tv_sec = i->it_value.tv_sec;
v32.it_value.tv_usec = i->it_value.tv_usec;
return copy_to_user(o, &v32, sizeof(struct compat_itimerval)) ? -EFAULT : 0;
}
#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(VERIFY_READ, 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 (!access_ok(VERIFY_READ, umask, bitmap_size / 8))
return -EFAULT;
user_access_begin();
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_access_end();
return 0;
Efault:
user_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 (!access_ok(VERIFY_WRITE, umask, bitmap_size / 8))
return -EFAULT;
user_access_begin();
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_access_end();
return 0;
Efault:
user_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 );
case 3: set->sig[2] = v.sig[4] | (((long)v.sig[5]) << 32 );
case 2: set->sig[1] = v.sig[2] | (((long)v.sig[3]) << 32 );
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(VERIFY_WRITE, ptr, len)))
return NULL;
return ptr;
}
EXPORT_SYMBOL_GPL(compat_alloc_user_space);