net/sunrpc/auth_gss/gss_krb5_seal.c

   1 /*
   2  *  linux/net/sunrpc/gss_krb5_seal.c
   3  *
   4  *  Adapted from MIT Kerberos 5-1.2.1 lib/gssapi/krb5/k5seal.c
   5  *
   6  *  Copyright (c) 2000-2008 The Regents of the University of Michigan.
   7  *  All rights reserved.
   8  *
   9  *  Andy Adamson        <andros@umich.edu>
  10  *  J. Bruce Fields     <bfields@umich.edu>
  11  */
  12
  13 /*
  14  * Copyright 1993 by OpenVision Technologies, Inc.
  15  *
  16  * Permission to use, copy, modify, distribute, and sell this software
  17  * and its documentation for any purpose is hereby granted without fee,
  18  * provided that the above copyright notice appears in all copies and
  19  * that both that copyright notice and this permission notice appear in
  20  * supporting documentation, and that the name of OpenVision not be used
  21  * in advertising or publicity pertaining to distribution of the software
  22  * without specific, written prior permission. OpenVision makes no
  23  * representations about the suitability of this software for any
  24  * purpose.  It is provided "as is" without express or implied warranty.
  25  *
  26  * OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  27  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  28  * EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  29  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
  30  * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
  31  * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  32  * PERFORMANCE OF THIS SOFTWARE.
  33  */
  34
  35 /*
  36  * Copyright (C) 1998 by the FundsXpress, INC.
  37  *
  38  * All rights reserved.
  39  *
  40  * Export of this software from the United States of America may require
  41  * a specific license from the United States Government.  It is the
  42  * responsibility of any person or organization contemplating export to
  43  * obtain such a license before exporting.
  44  *
  45  * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
  46  * distribute this software and its documentation for any purpose and
  47  * without fee is hereby granted, provided that the above copyright
  48  * notice appear in all copies and that both that copyright notice and
  49  * this permission notice appear in supporting documentation, and that
  50  * the name of FundsXpress. not be used in advertising or publicity pertaining
  51  * to distribution of the software without specific, written prior
  52  * permission.  FundsXpress makes no representations about the suitability of
  53  * this software for any purpose.  It is provided "as is" without express
  54  * or implied warranty.
  55  *
  56  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  57  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  58  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  59  */
  60
  61 #include <linux/types.h>
  62 #include <linux/jiffies.h>
  63 #include <linux/sunrpc/gss_krb5.h>
  64 #include <linux/random.h>
  65 #include <linux/crypto.h>
  66 #include <linux/atomic.h>
  67
  68 #include "gss_krb5_internal.h"
  69
  70 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
  71 # define RPCDBG_FACILITY        RPCDBG_AUTH
  72 #endif
  73
  74 static void *
  75 setup_token_v2(struct krb5_ctx *ctx, struct xdr_netobj *token)
  76 {
  77         u16 *ptr;
  78         void *krb5_hdr;
  79         u8 *p, flags = 0x00;
  80
  81         if ((ctx->flags & KRB5_CTX_FLAG_INITIATOR) == 0)
  82                 flags |= 0x01;
  83         if (ctx->flags & KRB5_CTX_FLAG_ACCEPTOR_SUBKEY)
  84                 flags |= 0x04;
  85
  86         /* Per rfc 4121, sec 4.2.6.1, there is no header,
  87          * just start the token.
  88          */
  89         krb5_hdr = (u16 *)token->data;
  90         ptr = krb5_hdr;
  91
  92         *ptr++ = KG2_TOK_MIC;
  93         p = (u8 *)ptr;
  94         *p++ = flags;
  95         *p++ = 0xff;
  96         ptr = (u16 *)p;
  97         *ptr++ = 0xffff;
  98         *ptr = 0xffff;
  99
 100         token->len = GSS_KRB5_TOK_HDR_LEN + ctx->gk5e->cksumlength;
 101         return krb5_hdr;
 102 }
 103
 104 u32
 105 gss_krb5_get_mic_v2(struct krb5_ctx *ctx, struct xdr_buf *text,
 106                     struct xdr_netobj *token)
 107 {
 108         struct crypto_ahash *tfm = ctx->initiate ?
 109                                    ctx->initiator_sign : ctx->acceptor_sign;
 110         struct xdr_netobj cksumobj = {
 111                 .len =  ctx->gk5e->cksumlength,
 112         };
 113         __be64 seq_send_be64;
 114         void *krb5_hdr;
 115         time64_t now;
 116
 117         dprintk("RPC:       %s\n", __func__);
 118
 119         krb5_hdr = setup_token_v2(ctx, token);
 120
 121         /* Set up the sequence number. Now 64-bits in clear
 122          * text and w/o direction indicator */
 123         seq_send_be64 = cpu_to_be64(atomic64_fetch_inc(&ctx->seq_send64));
 124         memcpy(krb5_hdr + 8, (char *) &seq_send_be64, 8);
 125
 126         cksumobj.data = krb5_hdr + GSS_KRB5_TOK_HDR_LEN;
 127         if (gss_krb5_checksum(tfm, krb5_hdr, GSS_KRB5_TOK_HDR_LEN,
 128                               text, 0, &cksumobj))
 129                 return GSS_S_FAILURE;
 130
 131         now = ktime_get_real_seconds();
 132         return (ctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
 133 }