Revision 89c38422e072bb453e3045b8f1b962a344c3edea authored by John Garry on 08 November 2018, 10:17:03 UTC, committed by Rob Herring on 08 November 2018, 18:44:34 UTC
Currently the NUMA distance map parsing does not validate the distance
table for the distance-matrix rules 1-2 in [1].

However the arch NUMA code may enforce some of these rules, but not all.
Such is the case for the arm64 port, which does not enforce the rule that
the distance between separates nodes cannot equal LOCAL_DISTANCE.

The patch adds the following rules validation:
- distance of node to self equals LOCAL_DISTANCE
- distance of separate nodes > LOCAL_DISTANCE

This change avoids a yet-unresolved crash reported in [2].

A note on dealing with symmetrical distances between nodes:

Validating symmetrical distances between nodes is difficult. If it were
mandated in the bindings that every distance must be recorded in the
table, then it would be easy. However, it isn't.

In addition to this, it is also possible to record [b, a] distance only
(and not [a, b]). So, when processing the table for [b, a], we cannot
assert that current distance of [a, b] != [b, a] as invalid, as [a, b]
distance may not be present in the table and current distance would be
default at REMOTE_DISTANCE.

As such, we maintain the policy that we overwrite distance [a, b] = [b, a]
for b > a. This policy is different to kernel ACPI SLIT validation, which
allows non-symmetrical distances (ACPI spec SLIT rules allow it). However,
the distance debug message is dropped as it may be misleading (for a distance
which is later overwritten).

Some final notes on semantics:

- It is implied that it is the responsibility of the arch NUMA code to
  reset the NUMA distance map for an error in distance map parsing.

- It is the responsibility of the FW NUMA topology parsing (whether OF or
  ACPI) to enforce NUMA distance rules, and not arch NUMA code.

[1] Documents/devicetree/bindings/numa.txt
[2] https://www.spinics.net/lists/arm-kernel/msg683304.html

Cc: stable@vger.kernel.org # 4.7
Signed-off-by: John Garry <john.garry@huawei.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Rob Herring <robh@kernel.org>
1 parent 6778be4
Raw File
compat.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 compat_timeval __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 compat_timeval __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 compat_timespec __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 compat_timespec __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);
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