fs/compat.c

   1 /*
   2  *  linux/fs/compat.c
   3  *
   4  *  Kernel compatibililty routines for e.g. 32 bit syscall support
   5  *  on 64 bit kernels.
   6  *
   7  *  Copyright (C) 2002       Stephen Rothwell, IBM Corporation
   8  *  Copyright (C) 1997-2000  Jakub Jelinek  (jakub@redhat.com)
   9  *  Copyright (C) 1998       Eddie C. Dost  (ecd@skynet.be)
  10  *  Copyright (C) 2001,2002  Andi Kleen, SuSE Labs
  11  *  Copyright (C) 2003       Pavel Machek (pavel@ucw.cz)
  12  *
  13  *  This program is free software; you can redistribute it and/or modify
  14  *  it under the terms of the GNU General Public License version 2 as
  15  *  published by the Free Software Foundation.
  16  */
  17
  18 #include <linux/compat.h>
  19 #include <linux/nfs4_mount.h>
  20 #include <linux/syscalls.h>
  21 #include <linux/slab.h>
  22 #include <linux/uaccess.h>
  23 #include "internal.h"
  24
  25 struct compat_nfs_string {
  26         compat_uint_t len;
  27         compat_uptr_t data;
  28 };
  29
  30 static inline void compat_nfs_string(struct nfs_string *dst,
  31                                      struct compat_nfs_string *src)
  32 {
  33         dst->data = compat_ptr(src->data);
  34         dst->len = src->len;
  35 }
  36
  37 struct compat_nfs4_mount_data_v1 {
  38         compat_int_t version;
  39         compat_int_t flags;
  40         compat_int_t rsize;
  41         compat_int_t wsize;
  42         compat_int_t timeo;
  43         compat_int_t retrans;
  44         compat_int_t acregmin;
  45         compat_int_t acregmax;
  46         compat_int_t acdirmin;
  47         compat_int_t acdirmax;
  48         struct compat_nfs_string client_addr;
  49         struct compat_nfs_string mnt_path;
  50         struct compat_nfs_string hostname;
  51         compat_uint_t host_addrlen;
  52         compat_uptr_t host_addr;
  53         compat_int_t proto;
  54         compat_int_t auth_flavourlen;
  55         compat_uptr_t auth_flavours;
  56 };
  57
  58 static int do_nfs4_super_data_conv(void *raw_data)
  59 {
  60         int version = *(compat_uint_t *) raw_data;
  61
  62         if (version == 1) {
  63                 struct compat_nfs4_mount_data_v1 *raw = raw_data;
  64                 struct nfs4_mount_data *real = raw_data;
  65
  66                 /* copy the fields backwards */
  67                 real->auth_flavours = compat_ptr(raw->auth_flavours);
  68                 real->auth_flavourlen = raw->auth_flavourlen;
  69                 real->proto = raw->proto;
  70                 real->host_addr = compat_ptr(raw->host_addr);
  71                 real->host_addrlen = raw->host_addrlen;
  72                 compat_nfs_string(&real->hostname, &raw->hostname);
  73                 compat_nfs_string(&real->mnt_path, &raw->mnt_path);
  74                 compat_nfs_string(&real->client_addr, &raw->client_addr);
  75                 real->acdirmax = raw->acdirmax;
  76                 real->acdirmin = raw->acdirmin;
  77                 real->acregmax = raw->acregmax;
  78                 real->acregmin = raw->acregmin;
  79                 real->retrans = raw->retrans;
  80                 real->timeo = raw->timeo;
  81                 real->wsize = raw->wsize;
  82                 real->rsize = raw->rsize;
  83                 real->flags = raw->flags;
  84                 real->version = raw->version;
  85         }
  86
  87         return 0;
  88 }
  89
  90 #define NFS4_NAME       "nfs4"
  91
  92 COMPAT_SYSCALL_DEFINE5(mount, const char __user *, dev_name,
  93                        const char __user *, dir_name,
  94                        const char __user *, type, compat_ulong_t, flags,
  95                        const void __user *, data)
  96 {
  97         char *kernel_type;
  98         void *options;
  99         char *kernel_dev;
 100         int retval;
 101
 102         kernel_type = copy_mount_string(type);
 103         retval = PTR_ERR(kernel_type);
 104         if (IS_ERR(kernel_type))
 105                 goto out;
 106
 107         kernel_dev = copy_mount_string(dev_name);
 108         retval = PTR_ERR(kernel_dev);
 109         if (IS_ERR(kernel_dev))
 110                 goto out1;
 111
 112         options = copy_mount_options(data);
 113         retval = PTR_ERR(options);
 114         if (IS_ERR(options))
 115                 goto out2;
 116
 117         if (kernel_type && options) {
 118                 if (!strcmp(kernel_type, NFS4_NAME)) {
 119                         retval = -EINVAL;
 120                         if (do_nfs4_super_data_conv(options))
 121                                 goto out3;
 122                 }
 123         }
 124
 125         retval = do_mount(kernel_dev, dir_name, kernel_type, flags, options);
 126
 127  out3:
 128         kfree(options);
 129  out2:
 130         kfree(kernel_dev);
 131  out1:
 132         kfree(kernel_type);
 133  out:
 134         return retval;
 135 }