linux-stable/ipc/syscall.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

199 lines
4.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* sys_ipc() is the old de-multiplexer for the SysV IPC calls.
*
* This is really horribly ugly, and new architectures should just wire up
* the individual syscalls instead.
*/
#include <linux/unistd.h>
#include <linux/syscalls.h>
#include <linux/security.h>
#include <linux/ipc_namespace.h>
#include "util.h"
#ifdef __ARCH_WANT_SYS_IPC
#include <linux/errno.h>
#include <linux/ipc.h>
#include <linux/shm.h>
#include <linux/uaccess.h>
SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second,
unsigned long, third, void __user *, ptr, long, fifth)
{
int version, ret;
version = call >> 16; /* hack for backward compatibility */
call &= 0xffff;
switch (call) {
case SEMOP:
return ksys_semtimedop(first, (struct sembuf __user *)ptr,
second, NULL);
case SEMTIMEDOP:
if (IS_ENABLED(CONFIG_64BIT) || !IS_ENABLED(CONFIG_64BIT_TIME))
return ksys_semtimedop(first, ptr, second,
(const struct __kernel_timespec __user *)fifth);
else if (IS_ENABLED(CONFIG_COMPAT_32BIT_TIME))
return compat_ksys_semtimedop(first, ptr, second,
(const struct old_timespec32 __user *)fifth);
else
return -ENOSYS;
case SEMGET:
return ksys_semget(first, second, third);
case SEMCTL: {
unsigned long arg;
if (!ptr)
return -EINVAL;
if (get_user(arg, (unsigned long __user *) ptr))
return -EFAULT;
return ksys_semctl(first, second, third, arg);
}
case MSGSND:
return ksys_msgsnd(first, (struct msgbuf __user *) ptr,
second, third);
case MSGRCV:
switch (version) {
case 0: {
struct ipc_kludge tmp;
if (!ptr)
return -EINVAL;
if (copy_from_user(&tmp,
(struct ipc_kludge __user *) ptr,
sizeof(tmp)))
return -EFAULT;
return ksys_msgrcv(first, tmp.msgp, second,
tmp.msgtyp, third);
}
default:
return ksys_msgrcv(first,
(struct msgbuf __user *) ptr,
second, fifth, third);
}
case MSGGET:
return ksys_msgget((key_t) first, second);
case MSGCTL:
return ksys_msgctl(first, second,
(struct msqid_ds __user *)ptr);
case SHMAT:
switch (version) {
default: {
unsigned long raddr;
ret = do_shmat(first, (char __user *)ptr,
second, &raddr, SHMLBA);
if (ret)
return ret;
return put_user(raddr, (unsigned long __user *) third);
}
case 1:
/*
* This was the entry point for kernel-originating calls
* from iBCS2 in 2.2 days.
*/
return -EINVAL;
}
case SHMDT:
return ksys_shmdt((char __user *)ptr);
case SHMGET:
return ksys_shmget(first, second, third);
case SHMCTL:
return ksys_shmctl(first, second,
(struct shmid_ds __user *) ptr);
default:
return -ENOSYS;
}
}
#endif
#ifdef CONFIG_COMPAT
#include <linux/compat.h>
#ifndef COMPAT_SHMLBA
#define COMPAT_SHMLBA SHMLBA
#endif
struct compat_ipc_kludge {
compat_uptr_t msgp;
compat_long_t msgtyp;
};
#ifdef CONFIG_ARCH_WANT_OLD_COMPAT_IPC
COMPAT_SYSCALL_DEFINE6(ipc, u32, call, int, first, int, second,
u32, third, compat_uptr_t, ptr, u32, fifth)
{
int version;
u32 pad;
version = call >> 16; /* hack for backward compatibility */
call &= 0xffff;
switch (call) {
case SEMOP:
/* struct sembuf is the same on 32 and 64bit :)) */
return ksys_semtimedop(first, compat_ptr(ptr), second, NULL);
case SEMTIMEDOP:
if (!IS_ENABLED(CONFIG_COMPAT_32BIT_TIME))
return -ENOSYS;
return compat_ksys_semtimedop(first, compat_ptr(ptr), second,
compat_ptr(fifth));
case SEMGET:
return ksys_semget(first, second, third);
case SEMCTL:
if (!ptr)
return -EINVAL;
if (get_user(pad, (u32 __user *) compat_ptr(ptr)))
return -EFAULT;
return compat_ksys_semctl(first, second, third, pad);
case MSGSND:
return compat_ksys_msgsnd(first, ptr, second, third);
case MSGRCV: {
void __user *uptr = compat_ptr(ptr);
if (first < 0 || second < 0)
return -EINVAL;
if (!version) {
struct compat_ipc_kludge ipck;
if (!uptr)
return -EINVAL;
if (copy_from_user(&ipck, uptr, sizeof(ipck)))
return -EFAULT;
return compat_ksys_msgrcv(first, ipck.msgp, second,
ipck.msgtyp, third);
}
return compat_ksys_msgrcv(first, ptr, second, fifth, third);
}
case MSGGET:
return ksys_msgget(first, second);
case MSGCTL:
return compat_ksys_msgctl(first, second, compat_ptr(ptr));
case SHMAT: {
int err;
unsigned long raddr;
if (version == 1)
return -EINVAL;
err = do_shmat(first, compat_ptr(ptr), second, &raddr,
COMPAT_SHMLBA);
if (err < 0)
return err;
return put_user(raddr, (compat_ulong_t __user *)compat_ptr(third));
}
case SHMDT:
return ksys_shmdt(compat_ptr(ptr));
case SHMGET:
return ksys_shmget(first, (unsigned int)second, third);
case SHMCTL:
return compat_ksys_shmctl(first, second, compat_ptr(ptr));
}
return -ENOSYS;
}
#endif
#endif