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_skcipher *cipher;
  47         unsigned char *plain;
  48         s32 code;
  49
  50         dprintk("RPC:       %s:\n", __func__);
  51         cipher = crypto_alloc_skcipher(kctx->gk5e->encrypt_name, 0,
  52                                        CRYPTO_ALG_ASYNC);
  53         if (IS_ERR(cipher))
  54                 return PTR_ERR(cipher);
  55
  56         plain = kmalloc(8, GFP_NOFS);
  57         if (!plain)
  58                 return -ENOMEM;
  59
  60         plain[0] = (unsigned char) ((seqnum >> 24) & 0xff);
  61         plain[1] = (unsigned char) ((seqnum >> 16) & 0xff);
  62         plain[2] = (unsigned char) ((seqnum >> 8) & 0xff);
  63         plain[3] = (unsigned char) ((seqnum >> 0) & 0xff);
  64         plain[4] = direction;
  65         plain[5] = direction;
  66         plain[6] = direction;
  67         plain[7] = direction;
  68
  69         code = krb5_rc4_setup_seq_key(kctx, cipher, cksum);
  70         if (code)
  71                 goto out;
  72
  73         code = krb5_encrypt(cipher, cksum, plain, buf, 8);
  74 out:
  75         crypto_free_skcipher(cipher);
  76         kfree(plain);
  77         return code;
  78 }
  79 s32
  80 krb5_make_seq_num(struct krb5_ctx *kctx,
  81                 struct crypto_skcipher *key,
  82                 int direction,
  83                 u32 seqnum,
  84                 unsigned char *cksum, unsigned char *buf)
  85 {
  86         unsigned char *plain;
  87         s32 code;
  88
  89         if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC)
  90                 return krb5_make_rc4_seq_num(kctx, direction, seqnum,
  91                                              cksum, buf);
  92
  93         plain = kmalloc(8, GFP_NOFS);
  94         if (!plain)
  95                 return -ENOMEM;
  96
  97         plain[0] = (unsigned char) (seqnum & 0xff);
  98         plain[1] = (unsigned char) ((seqnum >> 8) & 0xff);
  99         plain[2] = (unsigned char) ((seqnum >> 16) & 0xff);
 100         plain[3] = (unsigned char) ((seqnum >> 24) & 0xff);
 101
 102         plain[4] = direction;
 103         plain[5] = direction;
 104         plain[6] = direction;
 105         plain[7] = direction;
 106
 107         code = krb5_encrypt(key, cksum, plain, buf, 8);
 108         kfree(plain);
 109         return code;
 110 }
 111
 112 static s32
 113 krb5_get_rc4_seq_num(struct krb5_ctx *kctx, unsigned char *cksum,
 114                      unsigned char *buf, int *direction, s32 *seqnum)
 115 {
 116         struct crypto_skcipher *cipher;
 117         unsigned char *plain;
 118         s32 code;
 119
 120         dprintk("RPC:       %s:\n", __func__);
 121         cipher = crypto_alloc_skcipher(kctx->gk5e->encrypt_name, 0,
 122                                        CRYPTO_ALG_ASYNC);
 123         if (IS_ERR(cipher))
 124                 return PTR_ERR(cipher);
 125
 126         code = krb5_rc4_setup_seq_key(kctx, cipher, cksum);
 127         if (code)
 128                 goto out;
 129
 130         plain = kmalloc(8, GFP_NOFS);
 131         if (!plain) {
 132                 code = -ENOMEM;
 133                 goto out;
 134         }
 135
 136         code = krb5_decrypt(cipher, cksum, buf, plain, 8);
 137         if (code)
 138                 goto out_plain;
 139
 140         if ((plain[4] != plain[5]) || (plain[4] != plain[6])
 141                                    || (plain[4] != plain[7])) {
 142                 code = (s32)KG_BAD_SEQ;
 143                 goto out_plain;
 144         }
 145
 146         *direction = plain[4];
 147
 148         *seqnum = ((plain[0] << 24) | (plain[1] << 16) |
 149                                         (plain[2] << 8) | (plain[3]));
 150 out_plain:
 151         kfree(plain);
 152 out:
 153         crypto_free_skcipher(cipher);
 154         return code;
 155 }
 156
 157 s32
 158 krb5_get_seq_num(struct krb5_ctx *kctx,
 159                unsigned char *cksum,
 160                unsigned char *buf,
 161                int *direction, u32 *seqnum)
 162 {
 163         s32 code;
 164         struct crypto_skcipher *key = kctx->seq;
 165         unsigned char *plain;
 166
 167         dprintk("RPC:       krb5_get_seq_num:\n");
 168
 169         if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC)
 170                 return krb5_get_rc4_seq_num(kctx, cksum, buf,
 171                                             direction, seqnum);
 172         plain = kmalloc(8, GFP_NOFS);
 173         if (!plain)
 174                 return -ENOMEM;
 175
 176         if ((code = krb5_decrypt(key, cksum, buf, plain, 8)))
 177                 goto out;
 178
 179         if ((plain[4] != plain[5]) || (plain[4] != plain[6]) ||
 180             (plain[4] != plain[7])) {
 181                 code = (s32)KG_BAD_SEQ;
 182                 goto out;
 183         }
 184
 185         *direction = plain[4];
 186
 187         *seqnum = ((plain[0]) |
 188                    (plain[1] << 8) | (plain[2] << 16) | (plain[3] << 24));
 189
 190 out:
 191         kfree(plain);
 192         return code;
 193 }