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 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
  69 # define RPCDBG_FACILITY        RPCDBG_AUTH
  70 #endif
  71
  72 static void *
  73 setup_token(struct krb5_ctx *ctx, struct xdr_netobj *token)
  74 {
  75         u16 *ptr;
  76         void *krb5_hdr;
  77         int body_size = GSS_KRB5_TOK_HDR_LEN + ctx->gk5e->cksumlength;
  78
  79         token->len = g_token_size(&ctx->mech_used, body_size);
  80
  81         ptr = (u16 *)token->data;
  82         g_make_token_header(&ctx->mech_used, body_size, (unsigned char **)&ptr);
  83
  84         /* ptr now at start of header described in rfc 1964, section 1.2.1: */
  85         krb5_hdr = ptr;
  86         *ptr++ = KG_TOK_MIC_MSG;
  87         /*
  88          * signalg is stored as if it were converted from LE to host endian, even
  89          * though it's an opaque pair of bytes according to the RFC.
  90          */
  91         *ptr++ = (__force u16)cpu_to_le16(ctx->gk5e->signalg);
  92         *ptr++ = SEAL_ALG_NONE;
  93         *ptr = 0xffff;
  94
  95         return krb5_hdr;
  96 }
  97
  98 static void *
  99 setup_token_v2(struct krb5_ctx *ctx, struct xdr_netobj *token)
 100 {
 101         u16 *ptr;
 102         void *krb5_hdr;
 103         u8 *p, flags = 0x00;
 104
 105         if ((ctx->flags & KRB5_CTX_FLAG_INITIATOR) == 0)
 106                 flags |= 0x01;
 107         if (ctx->flags & KRB5_CTX_FLAG_ACCEPTOR_SUBKEY)
 108                 flags |= 0x04;
 109
 110         /* Per rfc 4121, sec 4.2.6.1, there is no header,
 111          * just start the token */
 112         krb5_hdr = ptr = (u16 *)token->data;
 113
 114         *ptr++ = KG2_TOK_MIC;
 115         p = (u8 *)ptr;
 116         *p++ = flags;
 117         *p++ = 0xff;
 118         ptr = (u16 *)p;
 119         *ptr++ = 0xffff;
 120         *ptr = 0xffff;
 121
 122         token->len = GSS_KRB5_TOK_HDR_LEN + ctx->gk5e->cksumlength;
 123         return krb5_hdr;
 124 }
 125
 126 u32
 127 gss_seq_send_fetch_and_inc(struct krb5_ctx *ctx)
 128 {
 129         u32 old, seq_send = READ_ONCE(ctx->seq_send);
 130
 131         do {
 132                 old = seq_send;
 133                 seq_send = cmpxchg(&ctx->seq_send, old, old + 1);
 134         } while (old != seq_send);
 135         return seq_send;
 136 }
 137
 138 u64
 139 gss_seq_send64_fetch_and_inc(struct krb5_ctx *ctx)
 140 {
 141         u64 old, seq_send = READ_ONCE(ctx->seq_send);
 142
 143         do {
 144                 old = seq_send;
 145                 seq_send = cmpxchg64(&ctx->seq_send64, old, old + 1);
 146         } while (old != seq_send);
 147         return seq_send;
 148 }
 149
 150 static u32
 151 gss_get_mic_v1(struct krb5_ctx *ctx, struct xdr_buf *text,
 152                 struct xdr_netobj *token)
 153 {
 154         char                    cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
 155         struct xdr_netobj       md5cksum = {.len = sizeof(cksumdata),
 156                                             .data = cksumdata};
 157         void                    *ptr;
 158         s32                     now;
 159         u32                     seq_send;
 160         u8                      *cksumkey;
 161
 162         dprintk("RPC:       %s\n", __func__);
 163         BUG_ON(ctx == NULL);
 164
 165         now = get_seconds();
 166
 167         ptr = setup_token(ctx, token);
 168
 169         if (ctx->gk5e->keyed_cksum)
 170                 cksumkey = ctx->cksum;
 171         else
 172                 cksumkey = NULL;
 173
 174         if (make_checksum(ctx, ptr, 8, text, 0, cksumkey,
 175                           KG_USAGE_SIGN, &md5cksum))
 176                 return GSS_S_FAILURE;
 177
 178         memcpy(ptr + GSS_KRB5_TOK_HDR_LEN, md5cksum.data, md5cksum.len);
 179
 180         seq_send = gss_seq_send_fetch_and_inc(ctx);
 181
 182         if (krb5_make_seq_num(ctx, ctx->seq, ctx->initiate ? 0 : 0xff,
 183                               seq_send, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8))
 184                 return GSS_S_FAILURE;
 185
 186         return (ctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
 187 }
 188
 189 static u32
 190 gss_get_mic_v2(struct krb5_ctx *ctx, struct xdr_buf *text,
 191                 struct xdr_netobj *token)
 192 {
 193         char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
 194         struct xdr_netobj cksumobj = { .len = sizeof(cksumdata),
 195                                        .data = cksumdata};
 196         void *krb5_hdr;
 197         s32 now;
 198         u8 *cksumkey;
 199         unsigned int cksum_usage;
 200         __be64 seq_send_be64;
 201
 202         dprintk("RPC:       %s\n", __func__);
 203
 204         krb5_hdr = setup_token_v2(ctx, token);
 205
 206         /* Set up the sequence number. Now 64-bits in clear
 207          * text and w/o direction indicator */
 208         seq_send_be64 = cpu_to_be64(gss_seq_send64_fetch_and_inc(ctx));
 209         memcpy(krb5_hdr + 8, (char *) &seq_send_be64, 8);
 210
 211         if (ctx->initiate) {
 212                 cksumkey = ctx->initiator_sign;
 213                 cksum_usage = KG_USAGE_INITIATOR_SIGN;
 214         } else {
 215                 cksumkey = ctx->acceptor_sign;
 216                 cksum_usage = KG_USAGE_ACCEPTOR_SIGN;
 217         }
 218
 219         if (make_checksum_v2(ctx, krb5_hdr, GSS_KRB5_TOK_HDR_LEN,
 220                              text, 0, cksumkey, cksum_usage, &cksumobj))
 221                 return GSS_S_FAILURE;
 222
 223         memcpy(krb5_hdr + GSS_KRB5_TOK_HDR_LEN, cksumobj.data, cksumobj.len);
 224
 225         now = get_seconds();
 226
 227         return (ctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
 228 }
 229
 230 u32
 231 gss_get_mic_kerberos(struct gss_ctx *gss_ctx, struct xdr_buf *text,
 232                      struct xdr_netobj *token)
 233 {
 234         struct krb5_ctx         *ctx = gss_ctx->internal_ctx_id;
 235
 236         switch (ctx->enctype) {
 237         default:
 238                 BUG();
 239         case ENCTYPE_DES_CBC_RAW:
 240         case ENCTYPE_DES3_CBC_RAW:
 241         case ENCTYPE_ARCFOUR_HMAC:
 242                 return gss_get_mic_v1(ctx, text, token);
 243         case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
 244         case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
 245                 return gss_get_mic_v2(ctx, text, token);
 246         }
 247 }