security/keys/compat_dh.c

   1 /* 32-bit compatibility syscall for 64-bit systems for DH operations
   2  *
   3  * Copyright (C) 2016 Stephan Mueller <smueller@chronox.de>
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; either version
   8  * 2 of the License, or (at your option) any later version.
   9  */
  10
  11 #include <linux/uaccess.h>
  12
  13 #include "internal.h"
  14
  15 /*
  16  * Perform the DH computation or DH based key derivation.
  17  *
  18  * If successful, 0 will be returned.
  19  */
  20 long compat_keyctl_dh_compute(struct keyctl_dh_params __user *params,
  21                               char __user *buffer, size_t buflen,
  22                               struct compat_keyctl_kdf_params __user *kdf)
  23 {
  24         struct keyctl_kdf_params kdfcopy;
  25         struct compat_keyctl_kdf_params compat_kdfcopy;
  26
  27         if (!kdf)
  28                 return __keyctl_dh_compute(params, buffer, buflen, NULL);
  29
  30         if (copy_from_user(&compat_kdfcopy, kdf, sizeof(compat_kdfcopy)) != 0)
  31                 return -EFAULT;
  32
  33         kdfcopy.hashname = compat_ptr(compat_kdfcopy.hashname);
  34         kdfcopy.otherinfo = compat_ptr(compat_kdfcopy.otherinfo);
  35         kdfcopy.otherinfolen = compat_kdfcopy.otherinfolen;
  36         memcpy(kdfcopy.__spare, compat_kdfcopy.__spare,
  37                sizeof(kdfcopy.__spare));
  38
  39         return __keyctl_dh_compute(params, buffer, buflen, &kdfcopy);
  40 }