linux/ipc/syscall.c
Dominik Brodowski d969c6fa72 ipc: add semctl syscall/compat_syscall wrappers
Provide ksys_semctl() and compat_ksys_semctl() wrappers to avoid in-kernel
calls to these syscalls. The ksys_ prefix denotes that these functions are
meant as a drop-in replacement for the syscalls. In particular, they use
the same calling convention as sys_semctl() and compat_sys_semctl().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02 20:15:22 +02:00

192 lines
4.4 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:
return ksys_semtimedop(first, (struct sembuf __user *)ptr,
second,
(const struct timespec __user *)fifth);
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 sys_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 sys_msgrcv(first, tmp.msgp, second,
tmp.msgtyp, third);
}
default:
return sys_msgrcv(first,
(struct msgbuf __user *) ptr,
second, fifth, third);
}
case MSGGET:
return sys_msgget((key_t) first, second);
case MSGCTL:
return sys_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 sys_shmdt((char __user *)ptr);
case SHMGET:
return sys_shmget(first, second, third);
case SHMCTL:
return sys_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:
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_sys_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_sys_msgrcv(first, ipck.msgp, second,
ipck.msgtyp, third);
}
return compat_sys_msgrcv(first, ptr, second, fifth, third);
}
case MSGGET:
return sys_msgget(first, second);
case MSGCTL:
return compat_sys_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 sys_shmdt(compat_ptr(ptr));
case SHMGET:
return sys_shmget(first, (unsigned)second, third);
case SHMCTL:
return compat_sys_shmctl(first, second, compat_ptr(ptr));
}
return -ENOSYS;
}
#endif
#endif