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[8];
  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[0] = (unsigned char) ((seqnum >> 24) & 0xff);
  56         plain[1] = (unsigned char) ((seqnum >> 16) & 0xff);
  57         plain[2] = (unsigned char) ((seqnum >> 8) & 0xff);
  58         plain[3] = (unsigned char) ((seqnum >> 0) & 0xff);
  59         plain[4] = direction;
  60         plain[5] = direction;
  61         plain[6] = direction;
  62         plain[7] = direction;
  63
  64         code = krb5_rc4_setup_seq_key(kctx, cipher, cksum);
  65         if (code)
  66                 goto out;
  67
  68         code = krb5_encrypt(cipher, cksum, plain, buf, 8);
  69 out:
  70         crypto_free_sync_skcipher(cipher);
  71         return code;
  72 }
  73 s32
  74 krb5_make_seq_num(struct krb5_ctx *kctx,
  75                 struct crypto_sync_skcipher *key,
  76                 int direction,
  77                 u32 seqnum,
  78                 unsigned char *cksum, unsigned char *buf)
  79 {
  80         unsigned char plain[8];
  81
  82         if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC)
  83                 return krb5_make_rc4_seq_num(kctx, direction, seqnum,
  84                                              cksum, buf);
  85
  86         plain[0] = (unsigned char) (seqnum & 0xff);
  87         plain[1] = (unsigned char) ((seqnum >> 8) & 0xff);
  88         plain[2] = (unsigned char) ((seqnum >> 16) & 0xff);
  89         plain[3] = (unsigned char) ((seqnum >> 24) & 0xff);
  90
  91         plain[4] = direction;
  92         plain[5] = direction;
  93         plain[6] = direction;
  94         plain[7] = direction;
  95
  96         return krb5_encrypt(key, cksum, plain, buf, 8);
  97 }
  98
  99 static s32
 100 krb5_get_rc4_seq_num(struct krb5_ctx *kctx, unsigned char *cksum,
 101                      unsigned char *buf, int *direction, s32 *seqnum)
 102 {
 103         struct crypto_sync_skcipher *cipher;
 104         unsigned char plain[8];
 105         s32 code;
 106
 107         dprintk("RPC:       %s:\n", __func__);
 108         cipher = crypto_alloc_sync_skcipher(kctx->gk5e->encrypt_name, 0, 0);
 109         if (IS_ERR(cipher))
 110                 return PTR_ERR(cipher);
 111
 112         code = krb5_rc4_setup_seq_key(kctx, cipher, cksum);
 113         if (code)
 114                 goto out;
 115
 116         code = krb5_decrypt(cipher, cksum, buf, plain, 8);
 117         if (code)
 118                 goto out;
 119
 120         if ((plain[4] != plain[5]) || (plain[4] != plain[6])
 121                                    || (plain[4] != plain[7])) {
 122                 code = (s32)KG_BAD_SEQ;
 123                 goto out;
 124         }
 125
 126         *direction = plain[4];
 127
 128         *seqnum = ((plain[0] << 24) | (plain[1] << 16) |
 129                                         (plain[2] << 8) | (plain[3]));
 130 out:
 131         crypto_free_sync_skcipher(cipher);
 132         return code;
 133 }
 134
 135 s32
 136 krb5_get_seq_num(struct krb5_ctx *kctx,
 137                unsigned char *cksum,
 138                unsigned char *buf,
 139                int *direction, u32 *seqnum)
 140 {
 141         s32 code;
 142         unsigned char plain[8];
 143         struct crypto_sync_skcipher *key = kctx->seq;
 144
 145         dprintk("RPC:       krb5_get_seq_num:\n");
 146
 147         if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC)
 148                 return krb5_get_rc4_seq_num(kctx, cksum, buf,
 149                                             direction, seqnum);
 150
 151         if ((code = krb5_decrypt(key, cksum, buf, plain, 8)))
 152                 return code;
 153
 154         if ((plain[4] != plain[5]) || (plain[4] != plain[6]) ||
 155             (plain[4] != plain[7]))
 156                 return (s32)KG_BAD_SEQ;
 157
 158         *direction = plain[4];
 159
 160         *seqnum = ((plain[0]) |
 161                    (plain[1] << 8) | (plain[2] << 16) | (plain[3] << 24));
 162
 163         return 0;
 164 }