// SPDX-License-Identifier: GPL-2.0-only
/*
* arch/arm/kernel/sys_oabi-compat.c
*
* Compatibility wrappers for syscalls that are used from
* old ABI user space binaries with an EABI kernel.
*
* Author: Nicolas Pitre
* Created: Oct 7, 2005
* Copyright: MontaVista Software, Inc.
*/
#include <asm/syscalls.h>
/*
* The legacy ABI and the new ARM EABI have different rules making some
* syscalls incompatible especially with structure arguments.
* Most notably, Eabi says 64-bit members should be 64-bit aligned instead of
* simply word aligned. EABI also pads structures to the size of the largest
* member it contains instead of the invariant 32-bit.
*
* The following syscalls are affected:
*
* sys_stat64:
* sys_lstat64:
* sys_fstat64:
* sys_fstatat64:
*
* struct stat64 has different sizes and some members are shifted
* Compatibility wrappers are needed for them and provided below.
*
* sys_fcntl64:
*
* struct flock64 has different sizes and some members are shifted
* A compatibility wrapper is needed and provided below.
*
* sys_statfs64:
* sys_fstatfs64:
*
* struct statfs64 has extra padding with EABI growing its size from
* 84 to 88. This struct is now __attribute__((packed,aligned(4)))
* with a small assembly wrapper to force the sz argument to 84 if it is 88
* to avoid copying the extra padding over user space unexpecting it.
*
* sys_newuname:
*
* struct new_utsname has no padding with EABI. No problem there.
*
* sys_epoll_ctl:
* sys_epoll_wait:
*
* struct epoll_event has its second member shifted also affecting the
* structure size. Compatibility wrappers are needed and provided below.
*
* sys_ipc:
* sys_semop:
* sys_semtimedop:
*
* struct sembuf loses its padding with EABI. Since arrays of them are
* used they have to be copyed to remove the padding. Compatibility wrappers
* provided below.
*
* sys_bind:
* sys_connect:
* sys_sendmsg:
* sys_sendto:
* sys_socketcall:
*
* struct sockaddr_un loses its padding with EABI. Since the size of the
* structure is used as a validation test in unix_mkname(), we need to
* change the length argument to 110 whenever it is 112. Compatibility
* wrappers provided below.
*/
#include <linux/syscalls.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/filelock.h>
#include <linux/cred.h>
#include <linux/fcntl.h>
#include <linux/eventpoll.h>
#include <linux/sem.h>
#include <linux/socket.h>
#include <linux/net.h>
#include <linux/ipc.h>
#include <linux/ipc_namespace.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <asm/syscall.h>
struct oldabi_stat64 {
unsigned long long st_dev;
unsigned int __pad1;
unsigned long __st_ino;
unsigned int st_mode;
unsigned int st_nlink;
unsigned long st_uid;
unsigned long st_gid;
unsigned long long st_rdev;
unsigned int __pad2;
long long st_size;
unsigned long st_blksize;
unsigned long long st_blocks;
unsigned long st_atime;
unsigned long st_atime_nsec;
unsigned long st_mtime;
unsigned long st_mtime_nsec;
unsigned long st_ctime;
unsigned long st_ctime_nsec;
unsigned long long st_ino;
} __attribute__ ((packed,aligned(4)));
static long cp_oldabi_stat64(struct kstat *stat,
struct oldabi_stat64 __user *statbuf)
{
struct oldabi_stat64 tmp;
tmp.st_dev = huge_encode_dev(stat->dev);
tmp.__pad1 = 0;
tmp.__st_ino = stat->ino;
tmp.st_mode = stat->mode;
tmp.st_nlink = stat->nlink;
tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
tmp.st_rdev = huge_encode_dev(stat->rdev);
tmp.st_size = stat->size;
tmp.st_blocks = stat->blocks;
tmp.__pad2 = 0;
tmp.st_blksize = stat->blksize;
tmp.st_atime = stat->atime.tv_sec;
tmp.st_atime_nsec = stat->atime.tv_nsec;
tmp.st_mtime = stat->mtime.tv_sec;
tmp.st_mtime_nsec = stat->mtime.tv_nsec;
tmp.st_ctime = stat->ctime.tv_sec;
tmp.st_ctime_nsec = stat->ctime.tv_nsec;
tmp.st_ino = stat->ino;
return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
}
asmlinkage long sys_oabi_stat64(const char __user * filename,
struct oldabi_stat64 __user * statbuf)
{
struct kstat stat;
int error = vfs_stat(filename, &stat);
if (!error)
error = cp_oldabi_stat64(&stat, statbuf);
return error;
}
asmlinkage long sys_oabi_lstat64(const char __user * filename,
struct oldabi_stat64 __user * statbuf)
{
struct kstat stat;
int error = vfs_lstat(filename, &stat);
if (!error)
error = cp_oldabi_stat64(&stat, statbuf);
return error;
}
asmlinkage long sys_oabi_fstat64(unsigned long fd,
struct oldabi_stat64 __user * statbuf)
{
struct kstat stat;
int error = vfs_fstat(fd, &stat);
if (!error)
error = cp_oldabi_stat64(&stat, statbuf);
return error;
}
asmlinkage long sys_oabi_fstatat64(int dfd,
const char __user *filename,
struct oldabi_stat64 __user *statbuf,
int flag)
{
struct kstat stat;
int error;
error = vfs_fstatat(dfd, filename, &stat, flag);
if (error)
return error;
return cp_oldabi_stat64(&stat, statbuf);
}
struct oabi_flock64 {
short l_type;
short l_whence;
loff_t l_start;
loff_t l_len;
pid_t l_pid;
} __attribute__ ((packed,aligned(4)));
static int get_oabi_flock(struct flock64 *kernel, struct oabi_flock64 __user *arg)
{
struct oabi_flock64 user;
if (copy_from_user(&user, (struct oabi_flock64 __user *)arg,
sizeof(user)))
return -EFAULT;
kernel->l_type = user.l_type;
kernel->l_whence = user.l_whence;
kernel->l_start = user.l_start;
kernel->l_len = user.l_len;
kernel->l_pid = user.l_pid;
return 0;
}
static int put_oabi_flock(struct flock64 *kernel, struct oabi_flock64 __user *arg)
{
struct oabi_flock64 user;
user.l_type = kernel->l_type;
user.l_whence = kernel->l_whence;
user.l_start = kernel->l_start;
user.l_len = kernel->l_len;
user.l_pid = kernel->l_pid;
if (copy_to_user((struct oabi_flock64 __user *)arg,
&user, sizeof(user)))
return -EFAULT;
return 0;
}
asmlinkage long sys_oabi_fcntl64(unsigned int fd, unsigned int cmd,
unsigned long arg)
{
void __user *argp = (void __user *)arg;
struct fd f = fdget_raw(fd);
struct flock64 flock;
long err = -EBADF;
if (!f.file)
goto out;
switch (cmd) {
case F_GETLK64:
case F_OFD_GETLK:
err = security_file_fcntl(f.file, cmd, arg);
if (err)
break;
err = get_oabi_flock(&flock, argp);
if (err)
break;
err = fcntl_getlk64(f.file, cmd, &flock);
if (!err)
err = put_oabi_flock(&flock, argp);
break;
case F_SETLK64:
case F_SETLKW64:
case F_OFD_SETLK:
case F_OFD_SETLKW:
err = security_file_fcntl(f.file, cmd, arg);
if (err)
break;
err = get_oabi_flock(&flock, argp);
if (err)
break;
err = fcntl_setlk64(fd, f.file, cmd, &flock);
break;
default:
err = sys_fcntl64(fd, cmd, arg);
break;
}
fdput(f);
out:
return err;
}
struct oabi_epoll_event {
__poll_t events;
__u64 data;
} __attribute__ ((packed,aligned(4)));
#ifdef CONFIG_EPOLL
asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
struct oabi_epoll_event __user *event)
{
struct oabi_epoll_event user;
struct epoll_event kernel;
if (ep_op_has_event(op) &&
copy_from_user(&user, event, sizeof(user)))
return -EFAULT;
kernel.events = user.events;
kernel.data = user.data;
return do_epoll_ctl(epfd, op, fd, &kernel, false);
}
#else
asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
struct oabi_epoll_event __user *event)
{
return -EINVAL;
}
#endif
struct epoll_event __user *
epoll_put_uevent(__poll_t revents, __u64 data,
struct epoll_event __user *uevent)
{
if (in_oabi_syscall()) {
struct oabi_epoll_event __user *oevent = (void __user *)uevent;
if (__put_user(revents, &oevent->events) ||
__put_user(data, &oevent->data))
return NULL;
return (void __user *)(oevent+1);
}
if (__put_user(revents, &uevent->events) ||
__put_user(data, &uevent->data))
return NULL;
return uevent+1;
}
struct oabi_sembuf {
unsigned short sem_num;
short sem_op;
short sem_flg;
unsigned short __pad;
};
#define sc_semopm sem_ctls[2]
#ifdef CONFIG_SYSVIPC
asmlinkage long sys_oabi_semtimedop(int semid,
struct oabi_sembuf __user *tsops,
unsigned nsops,
const struct old_timespec32 __user *timeout)
{
struct ipc_namespace *ns;
struct sembuf *sops;
long err;
int i;
ns = current->nsproxy->ipc_ns;
if (nsops > ns->sc_semopm)
return -E2BIG;
if (nsops < 1 || nsops > SEMOPM)
return -EINVAL;
sops = kvmalloc_array(nsops, sizeof(*sops), GFP_KERNEL);
if (!sops)
return -ENOMEM;
err = 0;
for (i = 0; i < nsops; i++) {
struct oabi_sembuf osb;
err |= copy_from_user(&osb, tsops, sizeof(osb));
sops[i].sem_num = osb.sem_num;
sops[i].sem_op = osb.sem_op;
sops[i].sem_flg = osb.sem_flg;
tsops++;
}
if (err) {
err = -EFAULT;
goto out;
}
if (timeout) {
struct timespec64 ts;
err = get_old_timespec32(&ts, timeout);
if (err)
goto out;
err = __do_semtimedop(semid, sops, nsops, &ts, ns);
goto out;
}
err = __do_semtimedop(semid, sops, nsops, NULL, ns);
out:
kvfree(sops);
return err;
}
asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops,
unsigned nsops)
{
return sys_oabi_semtimedop(semid, tsops, nsops, NULL);
}
asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third,
void __user *ptr, long fifth)
{
switch (call & 0xffff) {
case SEMOP:
return sys_oabi_semtimedop(first,
(struct oabi_sembuf __user *)ptr,
second, NULL);
case SEMTIMEDOP:
return sys_oabi_semtimedop(first,
(struct oabi_sembuf __user *)ptr,
second,
(const struct old_timespec32 __user *)fifth);
default:
return sys_ipc(call, first, second, third, ptr, fifth);
}
}
#else
asmlinkage long sys_oabi_semtimedop(int semid,
struct oabi_sembuf __user *tsops,
unsigned nsops,
const struct old_timespec32 __user *timeout)
{
return -ENOSYS;
}
asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops,
unsigned nsops)
{
return -ENOSYS;
}
asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third,
void __user *ptr, long fifth)
{
return -ENOSYS;
}
#endif
asmlinkage long sys_oabi_bind(int fd, struct sockaddr __user *addr, int addrlen)
{
sa_family_t sa_family;
if (addrlen == 112 &&
get_user(sa_family, &addr->sa_family) == 0 &&
sa_family == AF_UNIX)
addrlen = 110;
return sys_bind(fd, addr, addrlen);
}
asmlinkage long sys_oabi_connect(int fd, struct sockaddr __user *addr, int addrlen)
{
sa_family_t sa_family;
if (addrlen == 112 &&
get_user(sa_family, &addr->sa_family) == 0 &&
sa_family == AF_UNIX)
addrlen = 110;
return sys_connect(fd, addr, addrlen);
}
asmlinkage long sys_oabi_sendto(int fd, void __user *buff,
size_t len, unsigned flags,
struct sockaddr __user *addr,
int addrlen)
{
sa_family_t sa_family;
if (addrlen == 112 &&
get_user(sa_family, &addr->sa_family) == 0 &&
sa_family == AF_UNIX)
addrlen = 110;
return sys_sendto(fd, buff, len, flags, addr, addrlen);
}
asmlinkage long sys_oabi_sendmsg(int fd, struct user_msghdr __user *msg, unsigned flags)
{
struct sockaddr __user *addr;
int msg_namelen;
sa_family_t sa_family;
if (msg &&
get_user(msg_namelen, &msg->msg_namelen) == 0 &&
msg_namelen == 112 &&
get_user(addr, &msg->msg_name) == 0 &&
get_user(sa_family, &addr->sa_family) == 0 &&
sa_family == AF_UNIX)
{
/*
* HACK ALERT: there is a limit to how much backward bending
* we should do for what is actually a transitional
* compatibility layer. This already has known flaws with
* a few ioctls that we don't intend to fix. Therefore
* consider this blatent hack as another one... and take care
* to run for cover. In most cases it will "just work fine".
* If it doesn't, well, tough.
*/
put_user(110, &msg->msg_namelen);
}
return sys_sendmsg(fd, msg, flags);
}
asmlinkage long sys_oabi_socketcall(int call, unsigned long __user *args)
{
unsigned long r = -EFAULT, a[6];
switch (call) {
case SYS_BIND:
if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
r = sys_oabi_bind(a[0], (struct sockaddr __user *)a[1], a[2]);
break;
case SYS_CONNECT:
if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
r = sys_oabi_connect(a[0], (struct sockaddr __user *)a[1], a[2]);
break;
case SYS_SENDTO:
if (copy_from_user(a, args, 6 * sizeof(long)) == 0)
r = sys_oabi_sendto(a[0], (void __user *)a[1], a[2], a[3],
(struct sockaddr __user *)a[4], a[5]);
break;
case SYS_SENDMSG:
if (copy_from_user(a, args, 3 * sizeof(long)) == 0)
r = sys_oabi_sendmsg(a[0], (struct user_msghdr __user *)a[1], a[2]);
break;
default:
r = sys_socketcall(call, args);
}
return r;
}
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