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 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/slab.h>
  63 #include <linux/jiffies.h>
  64 #include <linux/sunrpc/gss_krb5.h>
  65 #include <linux/random.h>
  66 #include <asm/scatterlist.h>
  67 #include <linux/crypto.h>
  68
  69 #ifdef RPC_DEBUG
  70 # define RPCDBG_FACILITY        RPCDBG_AUTH
  71 #endif
  72
  73 static inline int
  74 gss_krb5_padding(int blocksize, int length) {
  75         /* Most of the code is block-size independent but in practice we
  76          * use only 8: */
  77         BUG_ON(blocksize != 8);
  78         return 8 - (length & 7);
  79 }
  80
  81 u32
  82 krb5_make_token(struct krb5_ctx *ctx, int qop_req,
  83                    struct xdr_buf *text, struct xdr_netobj *token,
  84                    int toktype)
  85 {
  86         s32                     checksum_type;
  87         struct xdr_netobj       md5cksum = {.len = 0, .data = NULL};
  88         int                     blocksize = 0, tmsglen;
  89         unsigned char           *ptr, *krb5_hdr, *msg_start;
  90         s32                     now;
  91
  92         dprintk("RPC:     gss_krb5_seal\n");
  93
  94         now = get_seconds();
  95
  96         if (qop_req != 0)
  97                 goto out_err;
  98
  99         switch (ctx->signalg) {
 100                 case SGN_ALG_DES_MAC_MD5:
 101                         checksum_type = CKSUMTYPE_RSA_MD5;
 102                         break;
 103                 default:
 104                         dprintk("RPC:      gss_krb5_seal: ctx->signalg %d not"
 105                                 " supported\n", ctx->signalg);
 106                         goto out_err;
 107         }
 108         if (ctx->sealalg != SEAL_ALG_NONE && ctx->sealalg != SEAL_ALG_DES) {
 109                 dprintk("RPC:      gss_krb5_seal: ctx->sealalg %d not supported\n",
 110                         ctx->sealalg);
 111                 goto out_err;
 112         }
 113
 114         if (toktype == KG_TOK_WRAP_MSG) {
 115                 blocksize = crypto_tfm_alg_blocksize(ctx->enc);
 116                 tmsglen = blocksize + text->len
 117                         + gss_krb5_padding(blocksize, blocksize + text->len);
 118         } else {
 119                 tmsglen = 0;
 120         }
 121
 122         token->len = g_token_size(&ctx->mech_used, 22 + tmsglen);
 123
 124         ptr = token->data;
 125         g_make_token_header(&ctx->mech_used, 22 + tmsglen, &ptr);
 126
 127         *ptr++ = (unsigned char) ((toktype>>8)&0xff);
 128         *ptr++ = (unsigned char) (toktype&0xff);
 129
 130         /* ptr now at byte 2 of header described in rfc 1964, section 1.2.1: */
 131         krb5_hdr = ptr - 2;
 132         msg_start = krb5_hdr + 24;
 133
 134         *(u16 *)(krb5_hdr + 2) = htons(ctx->signalg);
 135         memset(krb5_hdr + 4, 0xff, 4);
 136         if (toktype == KG_TOK_WRAP_MSG)
 137                 *(u16 *)(krb5_hdr + 4) = htons(ctx->sealalg);
 138
 139         if (toktype == KG_TOK_WRAP_MSG) {
 140                 /* XXX removing support for now */
 141                 goto out_err;
 142         } else { /* Sign only.  */
 143                 if (make_checksum(checksum_type, krb5_hdr, 8, text,
 144                                        &md5cksum))
 145                         goto out_err;
 146         }
 147
 148         switch (ctx->signalg) {
 149         case SGN_ALG_DES_MAC_MD5:
 150                 if (krb5_encrypt(ctx->seq, NULL, md5cksum.data,
 151                                   md5cksum.data, md5cksum.len))
 152                         goto out_err;
 153                 memcpy(krb5_hdr + 16,
 154                        md5cksum.data + md5cksum.len - KRB5_CKSUM_LENGTH,
 155                        KRB5_CKSUM_LENGTH);
 156
 157                 dprintk("RPC:      make_seal_token: cksum data: \n");
 158                 print_hexl((u32 *) (krb5_hdr + 16), KRB5_CKSUM_LENGTH, 0);
 159                 break;
 160         default:
 161                 BUG();
 162         }
 163
 164         kfree(md5cksum.data);
 165
 166         if ((krb5_make_seq_num(ctx->seq, ctx->initiate ? 0 : 0xff,
 167                                ctx->seq_send, krb5_hdr + 16, krb5_hdr + 8)))
 168                 goto out_err;
 169
 170         ctx->seq_send++;
 171
 172         return ((ctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE);
 173 out_err:
 174         if (md5cksum.data) kfree(md5cksum.data);
 175         return GSS_S_FAILURE;
 176 }