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
  67 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
  68 # define RPCDBG_FACILITY        RPCDBG_AUTH
  69 #endif
  70
  71 DEFINE_SPINLOCK(krb5_seq_lock);
  72
  73 static void *
  74 setup_token(struct krb5_ctx *ctx, struct xdr_netobj *token)
  75 {
  76         u16 *ptr;
  77         void *krb5_hdr;
  78         int body_size = GSS_KRB5_TOK_HDR_LEN + ctx->gk5e->cksumlength;
  79
  80         token->len = g_token_size(&ctx->mech_used, body_size);
  81
  82         ptr = (u16 *)token->data;
  83         g_make_token_header(&ctx->mech_used, body_size, (unsigned char **)&ptr);
  84
  85         /* ptr now at start of header described in rfc 1964, section 1.2.1: */
  86         krb5_hdr = ptr;
  87         *ptr++ = KG_TOK_MIC_MSG;
  88         /*
  89          * signalg is stored as if it were converted from LE to host endian, even
  90          * though it's an opaque pair of bytes according to the RFC.
  91          */
  92         *ptr++ = (__force u16)cpu_to_le16(ctx->gk5e->signalg);
  93         *ptr++ = SEAL_ALG_NONE;
  94         *ptr = 0xffff;
  95
  96         return krb5_hdr;
  97 }
  98
  99 static void *
 100 setup_token_v2(struct krb5_ctx *ctx, struct xdr_netobj *token)
 101 {
 102         u16 *ptr;
 103         void *krb5_hdr;
 104         u8 *p, flags = 0x00;
 105
 106         if ((ctx->flags & KRB5_CTX_FLAG_INITIATOR) == 0)
 107                 flags |= 0x01;
 108         if (ctx->flags & KRB5_CTX_FLAG_ACCEPTOR_SUBKEY)
 109                 flags |= 0x04;
 110
 111         /* Per rfc 4121, sec 4.2.6.1, there is no header,
 112          * just start the token */
 113         krb5_hdr = ptr = (u16 *)token->data;
 114
 115         *ptr++ = KG2_TOK_MIC;
 116         p = (u8 *)ptr;
 117         *p++ = flags;
 118         *p++ = 0xff;
 119         ptr = (u16 *)p;
 120         *ptr++ = 0xffff;
 121         *ptr = 0xffff;
 122
 123         token->len = GSS_KRB5_TOK_HDR_LEN + ctx->gk5e->cksumlength;
 124         return krb5_hdr;
 125 }
 126
 127 static u32
 128 gss_get_mic_v1(struct krb5_ctx *ctx, struct xdr_buf *text,
 129                 struct xdr_netobj *token)
 130 {
 131         char                    cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
 132         struct xdr_netobj       md5cksum = {.len = sizeof(cksumdata),
 133                                             .data = cksumdata};
 134         void                    *ptr;
 135         s32                     now;
 136         u32                     seq_send;
 137         u8                      *cksumkey;
 138
 139         dprintk("RPC:       %s\n", __func__);
 140         BUG_ON(ctx == NULL);
 141
 142         now = get_seconds();
 143
 144         ptr = setup_token(ctx, token);
 145
 146         if (ctx->gk5e->keyed_cksum)
 147                 cksumkey = ctx->cksum;
 148         else
 149                 cksumkey = NULL;
 150
 151         if (make_checksum(ctx, ptr, 8, text, 0, cksumkey,
 152                           KG_USAGE_SIGN, &md5cksum))
 153                 return GSS_S_FAILURE;
 154
 155         memcpy(ptr + GSS_KRB5_TOK_HDR_LEN, md5cksum.data, md5cksum.len);
 156
 157         spin_lock(&krb5_seq_lock);
 158         seq_send = ctx->seq_send++;
 159         spin_unlock(&krb5_seq_lock);
 160
 161         if (krb5_make_seq_num(ctx, ctx->seq, ctx->initiate ? 0 : 0xff,
 162                               seq_send, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8))
 163                 return GSS_S_FAILURE;
 164
 165         return (ctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
 166 }
 167
 168 static u32
 169 gss_get_mic_v2(struct krb5_ctx *ctx, struct xdr_buf *text,
 170                 struct xdr_netobj *token)
 171 {
 172         char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
 173         struct xdr_netobj cksumobj = { .len = sizeof(cksumdata),
 174                                        .data = cksumdata};
 175         void *krb5_hdr;
 176         s32 now;
 177         u64 seq_send;
 178         u8 *cksumkey;
 179         unsigned int cksum_usage;
 180
 181         dprintk("RPC:       %s\n", __func__);
 182
 183         krb5_hdr = setup_token_v2(ctx, token);
 184
 185         /* Set up the sequence number. Now 64-bits in clear
 186          * text and w/o direction indicator */
 187         spin_lock(&krb5_seq_lock);
 188         seq_send = ctx->seq_send64++;
 189         spin_unlock(&krb5_seq_lock);
 190         *((__be64 *)(krb5_hdr + 8)) = cpu_to_be64(seq_send);
 191
 192         if (ctx->initiate) {
 193                 cksumkey = ctx->initiator_sign;
 194                 cksum_usage = KG_USAGE_INITIATOR_SIGN;
 195         } else {
 196                 cksumkey = ctx->acceptor_sign;
 197                 cksum_usage = KG_USAGE_ACCEPTOR_SIGN;
 198         }
 199
 200         if (make_checksum_v2(ctx, krb5_hdr, GSS_KRB5_TOK_HDR_LEN,
 201                              text, 0, cksumkey, cksum_usage, &cksumobj))
 202                 return GSS_S_FAILURE;
 203
 204         memcpy(krb5_hdr + GSS_KRB5_TOK_HDR_LEN, cksumobj.data, cksumobj.len);
 205
 206         now = get_seconds();
 207
 208         return (ctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
 209 }
 210
 211 u32
 212 gss_get_mic_kerberos(struct gss_ctx *gss_ctx, struct xdr_buf *text,
 213                      struct xdr_netobj *token)
 214 {
 215         struct krb5_ctx         *ctx = gss_ctx->internal_ctx_id;
 216
 217         switch (ctx->enctype) {
 218         default:
 219                 BUG();
 220         case ENCTYPE_DES_CBC_RAW:
 221         case ENCTYPE_DES3_CBC_RAW:
 222         case ENCTYPE_ARCFOUR_HMAC:
 223                 return gss_get_mic_v1(ctx, text, token);
 224         case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
 225         case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
 226                 return gss_get_mic_v2(ctx, text, token);
 227         }
 228 }
 229