net/sunrpc/auth_gss/gss_krb5_seqnum.c

   1 /*
   2  *  linux/net/sunrpc/gss_krb5_seqnum.c
   3  *
   4  *  Adapted from MIT Kerberos 5-1.2.1 lib/gssapi/krb5/util_seqnum.c
   5  *
   6  *  Copyright (c) 2000 The Regents of the University of Michigan.
   7  *  All rights reserved.
   8  *
   9  *  Andy Adamson   <andros@umich.edu>
  10  */
  11
  12 /*
  13  * Copyright 1993 by OpenVision Technologies, Inc.
  14  *
  15  * Permission to use, copy, modify, distribute, and sell this software
  16  * and its documentation for any purpose is hereby granted without fee,
  17  * provided that the above copyright notice appears in all copies and
  18  * that both that copyright notice and this permission notice appear in
  19  * supporting documentation, and that the name of OpenVision not be used
  20  * in advertising or publicity pertaining to distribution of the software
  21  * without specific, written prior permission. OpenVision makes no
  22  * representations about the suitability of this software for any
  23  * purpose.  It is provided "as is" without express or implied warranty.
  24  *
  25  * OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  26  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  27  * EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  28  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
  29  * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
  30  * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  31  * PERFORMANCE OF THIS SOFTWARE.
  32  */
  33
  34 #include <crypto/skcipher.h>
  35 #include <linux/types.h>
  36 #include <linux/sunrpc/gss_krb5.h>
  37
  38 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
  39 # define RPCDBG_FACILITY        RPCDBG_AUTH
  40 #endif
  41
  42 static s32
  43 krb5_make_rc4_seq_num(struct krb5_ctx *kctx, int direction, s32 seqnum,
  44                       unsigned char *cksum, unsigned char *buf)
  45 {
  46         struct crypto_sync_skcipher *cipher;
  47         unsigned char *plain;
  48         s32 code;
  49
  50         dprintk("RPC:       %s:\n", __func__);
  51         cipher = crypto_alloc_sync_skcipher(kctx->gk5e->encrypt_name, 0, 0);
  52         if (IS_ERR(cipher))
  53                 return PTR_ERR(cipher);
  54
  55         plain = kmalloc(8, GFP_NOFS);
  56         if (!plain)
  57                 return -ENOMEM;
  58
  59         plain[0] = (unsigned char) ((seqnum >> 24) & 0xff);
  60         plain[1] = (unsigned char) ((seqnum >> 16) & 0xff);
  61         plain[2] = (unsigned char) ((seqnum >> 8) & 0xff);
  62         plain[3] = (unsigned char) ((seqnum >> 0) & 0xff);
  63         plain[4] = direction;
  64         plain[5] = direction;
  65         plain[6] = direction;
  66         plain[7] = direction;
  67
  68         code = krb5_rc4_setup_seq_key(kctx, cipher, cksum);
  69         if (code)
  70                 goto out;
  71
  72         code = krb5_encrypt(cipher, cksum, plain, buf, 8);
  73 out:
  74         kfree(plain);
  75         crypto_free_sync_skcipher(cipher);
  76         return code;
  77 }
  78 s32
  79 krb5_make_seq_num(struct krb5_ctx *kctx,
  80                 struct crypto_sync_skcipher *key,
  81                 int direction,
  82                 u32 seqnum,
  83                 unsigned char *cksum, unsigned char *buf)
  84 {
  85         unsigned char *plain;
  86         s32 code;
  87
  88         if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC)
  89                 return krb5_make_rc4_seq_num(kctx, direction, seqnum,
  90                                              cksum, buf);
  91
  92         plain = kmalloc(8, GFP_NOFS);
  93         if (!plain)
  94                 return -ENOMEM;
  95
  96         plain[0] = (unsigned char) (seqnum & 0xff);
  97         plain[1] = (unsigned char) ((seqnum >> 8) & 0xff);
  98         plain[2] = (unsigned char) ((seqnum >> 16) & 0xff);
  99         plain[3] = (unsigned char) ((seqnum >> 24) & 0xff);
 100
 101         plain[4] = direction;
 102         plain[5] = direction;
 103         plain[6] = direction;
 104         plain[7] = direction;
 105
 106         code = krb5_encrypt(key, cksum, plain, buf, 8);
 107         kfree(plain);
 108         return code;
 109 }
 110
 111 static s32
 112 krb5_get_rc4_seq_num(struct krb5_ctx *kctx, unsigned char *cksum,
 113                      unsigned char *buf, int *direction, s32 *seqnum)
 114 {
 115         struct crypto_sync_skcipher *cipher;
 116         unsigned char *plain;
 117         s32 code;
 118
 119         dprintk("RPC:       %s:\n", __func__);
 120         cipher = crypto_alloc_sync_skcipher(kctx->gk5e->encrypt_name, 0, 0);
 121         if (IS_ERR(cipher))
 122                 return PTR_ERR(cipher);
 123
 124         code = krb5_rc4_setup_seq_key(kctx, cipher, cksum);
 125         if (code)
 126                 goto out;
 127
 128         plain = kmalloc(8, GFP_NOFS);
 129         if (!plain) {
 130                 code = -ENOMEM;
 131                 goto out;
 132         }
 133
 134         code = krb5_decrypt(cipher, cksum, buf, plain, 8);
 135         if (code)
 136                 goto out_plain;
 137
 138         if ((plain[4] != plain[5]) || (plain[4] != plain[6])
 139                                    || (plain[4] != plain[7])) {
 140                 code = (s32)KG_BAD_SEQ;
 141                 goto out_plain;
 142         }
 143
 144         *direction = plain[4];
 145
 146         *seqnum = ((plain[0] << 24) | (plain[1] << 16) |
 147                                         (plain[2] << 8) | (plain[3]));
 148 out_plain:
 149         kfree(plain);
 150 out:
 151         crypto_free_sync_skcipher(cipher);
 152         return code;
 153 }
 154
 155 s32
 156 krb5_get_seq_num(struct krb5_ctx *kctx,
 157                unsigned char *cksum,
 158                unsigned char *buf,
 159                int *direction, u32 *seqnum)
 160 {
 161         s32 code;
 162         unsigned char *plain;
 163         struct crypto_sync_skcipher *key = kctx->seq;
 164
 165         dprintk("RPC:       krb5_get_seq_num:\n");
 166
 167         if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC)
 168                 return krb5_get_rc4_seq_num(kctx, cksum, buf,
 169                                             direction, seqnum);
 170         plain = kmalloc(8, GFP_NOFS);
 171         if (!plain)
 172                 return -ENOMEM;
 173
 174         if ((code = krb5_decrypt(key, cksum, buf, plain, 8)))
 175                 goto out;
 176
 177         if ((plain[4] != plain[5]) || (plain[4] != plain[6]) ||
 178             (plain[4] != plain[7])) {
 179                 code = (s32)KG_BAD_SEQ;
 180                 goto out;
 181         }
 182
 183         *direction = plain[4];
 184
 185         *seqnum = ((plain[0]) |
 186                    (plain[1] << 8) | (plain[2] << 16) | (plain[3] << 24));
 187
 188 out:
 189         kfree(plain);
 190         return code;
 191 }