LXR linux/net/sunrpc/auth_gss/gss_krb5

   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
  72static void *
  73setup_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
  98static void *
  99setup_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
 126static u32
 127gss_get_mic_v1(struct krb5_ctx *ctx, struct xdr_buf *text,
 128                struct xdr_netobj *token)
 129{
 130        char                    cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
 131        struct xdr_netobj       md5cksum = {.len = sizeof(cksumdata),
 132                                            .data = cksumdata};
 133        void                    *ptr;
 134        time64_t                now;
 135        u32                     seq_send;
 136        u8                      *cksumkey;
 137
 138        dprintk("RPC:       %s\n", __func__);
 139        BUG_ON(ctx == NULL);
 140
 141        now = ktime_get_real_seconds();
 142
 143        ptr = setup_token(ctx, token);
 144
 145        if (ctx->gk5e->keyed_cksum)
 146                cksumkey = ctx->cksum;
 147        else
 148                cksumkey = NULL;
 149
 150        if (make_checksum(ctx, ptr, 8, text, 0, cksumkey,
 151                          KG_USAGE_SIGN, &md5cksum))
 152                return GSS_S_FAILURE;
 153
 154        memcpy(ptr + GSS_KRB5_TOK_HDR_LEN, md5cksum.data, md5cksum.len);
 155
 156        seq_send = atomic_fetch_inc(&ctx->seq_send);
 157
 158        if (krb5_make_seq_num(ctx, ctx->seq, ctx->initiate ? 0 : 0xff,
 159                              seq_send, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8))
 160                return GSS_S_FAILURE;
 161
 162        return (ctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
 163}
 164
 165static u32
 166gss_get_mic_v2(struct krb5_ctx *ctx, struct xdr_buf *text,
 167                struct xdr_netobj *token)
 168{
 169        char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
 170        struct xdr_netobj cksumobj = { .len = sizeof(cksumdata),
 171                                       .data = cksumdata};
 172        void *krb5_hdr;
 173        time64_t now;
 174        u8 *cksumkey;
 175        unsigned int cksum_usage;
 176        __be64 seq_send_be64;
 177
 178        dprintk("RPC:       %s\n", __func__);
 179
 180        krb5_hdr = setup_token_v2(ctx, token);
 181
 182        /* Set up the sequence number. Now 64-bits in clear
 183         * text and w/o direction indicator */
 184        seq_send_be64 = cpu_to_be64(atomic64_fetch_inc(&ctx->seq_send64));
 185        memcpy(krb5_hdr + 8, (char *) &seq_send_be64, 8);
 186
 187        if (ctx->initiate) {
 188                cksumkey = ctx->initiator_sign;
 189                cksum_usage = KG_USAGE_INITIATOR_SIGN;
 190        } else {
 191                cksumkey = ctx->acceptor_sign;
 192                cksum_usage = KG_USAGE_ACCEPTOR_SIGN;
 193        }
 194
 195        if (make_checksum_v2(ctx, krb5_hdr, GSS_KRB5_TOK_HDR_LEN,
 196                             text, 0, cksumkey, cksum_usage, &cksumobj))
 197                return GSS_S_FAILURE;
 198
 199        memcpy(krb5_hdr + GSS_KRB5_TOK_HDR_LEN, cksumobj.data, cksumobj.len);
 200
 201        now = ktime_get_real_seconds();
 202
 203        return (ctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
 204}
 205
 206u32
 207gss_get_mic_kerberos(struct gss_ctx *gss_ctx, struct xdr_buf *text,
 208                     struct xdr_netobj *token)
 209{
 210        struct krb5_ctx         *ctx = gss_ctx->internal_ctx_id;
 211
 212        switch (ctx->enctype) {
 213        default:
 214                BUG();
 215        case ENCTYPE_DES_CBC_RAW:
 216        case ENCTYPE_DES3_CBC_RAW:
 217                return gss_get_mic_v1(ctx, text, token);
 218        case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
 219        case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
 220                return gss_get_mic_v2(ctx, text, token);
 221        }
 222}
 223