net/sunrpc/auth_gss/gss_spkm3_seal.c

   1 /*
   2  *  linux/net/sunrpc/gss_spkm3_seal.c
   3  *
   4  *  Copyright (c) 2003 The Regents of the University of Michigan.
   5  *  All rights reserved.
   6  *
   7  *  Andy Adamson <andros@umich.edu>
   8  *
   9  *  Redistribution and use in source and binary forms, with or without
  10  *  modification, are permitted provided that the following conditions
  11  *  are met:
  12  *
  13  *  1. Redistributions of source code must retain the above copyright
  14  *     notice, this list of conditions and the following disclaimer.
  15  *  2. Redistributions in binary form must reproduce the above copyright
  16  *     notice, this list of conditions and the following disclaimer in the
  17  *     documentation and/or other materials provided with the distribution.
  18  *  3. Neither the name of the University nor the names of its
  19  *     contributors may be used to endorse or promote products derived
  20  *     from this software without specific prior written permission.
  21  *
  22  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  23  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  24  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  25  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  27  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  28  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  29  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  30  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  31  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  32  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  33  *
  34  */
  35
  36 #include <linux/types.h>
  37 #include <linux/jiffies.h>
  38 #include <linux/sunrpc/gss_spkm3.h>
  39 #include <linux/random.h>
  40 #include <linux/crypto.h>
  41 #include <linux/pagemap.h>
  42 #include <linux/scatterlist.h>
  43 #include <linux/sunrpc/xdr.h>
  44
  45 #ifdef RPC_DEBUG
  46 # define RPCDBG_FACILITY        RPCDBG_AUTH
  47 #endif
  48
  49 const struct xdr_netobj hmac_md5_oid = { 8, "\x2B\x06\x01\x05\x05\x08\x01\x01"};
  50 const struct xdr_netobj cast5_cbc_oid = {9, "\x2A\x86\x48\x86\xF6\x7D\x07\x42\x0A"};
  51
  52 /*
  53  * spkm3_make_token()
  54  *
  55  * Only SPKM_MIC_TOK with md5 intg-alg is supported
  56  */
  57
  58 u32
  59 spkm3_make_token(struct spkm3_ctx *ctx,
  60                    struct xdr_buf * text, struct xdr_netobj * token,
  61                    int toktype)
  62 {
  63         s32                     checksum_type;
  64         char                    tokhdrbuf[25];
  65         char                    cksumdata[16];
  66         struct xdr_netobj       md5cksum = {.len = 0, .data = cksumdata};
  67         struct xdr_netobj       mic_hdr = {.len = 0, .data = tokhdrbuf};
  68         int                     tokenlen = 0;
  69         unsigned char           *ptr;
  70         s32                     now;
  71         int                     ctxelen = 0, ctxzbit = 0;
  72         int                     md5elen = 0, md5zbit = 0;
  73
  74         now = jiffies;
  75
  76         if (ctx->ctx_id.len != 16) {
  77                 dprintk("RPC:       spkm3_make_token BAD ctx_id.len %d\n",
  78                                 ctx->ctx_id.len);
  79                 goto out_err;
  80         }
  81
  82         if (!g_OID_equal(&ctx->intg_alg, &hmac_md5_oid)) {
  83                 dprintk("RPC:       gss_spkm3_seal: unsupported I-ALG "
  84                                 "algorithm.  only support hmac-md5 I-ALG.\n");
  85                 goto out_err;
  86         } else
  87                 checksum_type = CKSUMTYPE_HMAC_MD5;
  88
  89         if (!g_OID_equal(&ctx->conf_alg, &cast5_cbc_oid)) {
  90                 dprintk("RPC:       gss_spkm3_seal: unsupported C-ALG "
  91                                 "algorithm\n");
  92                 goto out_err;
  93         }
  94
  95         if (toktype == SPKM_MIC_TOK) {
  96                 /* Calculate checksum over the mic-header */
  97                 asn1_bitstring_len(&ctx->ctx_id, &ctxelen, &ctxzbit);
  98                 spkm3_mic_header(&mic_hdr.data, &mic_hdr.len, ctx->ctx_id.data,
  99                                 ctxelen, ctxzbit);
 100                 if (make_spkm3_checksum(checksum_type, &ctx->derived_integ_key,
 101                                         (char *)mic_hdr.data, mic_hdr.len,
 102                                         text, 0, &md5cksum))
 103                         goto out_err;
 104
 105                 asn1_bitstring_len(&md5cksum, &md5elen, &md5zbit);
 106                 tokenlen = 10 + ctxelen + 1 + md5elen + 1;
 107
 108                 /* Create token header using generic routines */
 109                 token->len = g_token_size(&ctx->mech_used, tokenlen + 2);
 110
 111                 ptr = token->data;
 112                 g_make_token_header(&ctx->mech_used, tokenlen + 2, &ptr);
 113
 114                 spkm3_make_mic_token(&ptr, tokenlen, &mic_hdr, &md5cksum, md5elen, md5zbit);
 115         } else if (toktype == SPKM_WRAP_TOK) { /* Not Supported */
 116                 dprintk("RPC:       gss_spkm3_seal: SPKM_WRAP_TOK "
 117                                 "not supported\n");
 118                 goto out_err;
 119         }
 120
 121         /* XXX need to implement sequence numbers, and ctx->expired */
 122
 123         return  GSS_S_COMPLETE;
 124 out_err:
 125         token->data = NULL;
 126         token->len = 0;
 127         return GSS_S_FAILURE;
 128 }
 129
 130 static int
 131 spkm3_checksummer(struct scatterlist *sg, void *data)
 132 {
 133         struct hash_desc *desc = data;
 134
 135         return crypto_hash_update(desc, sg, sg->length);
 136 }
 137
 138 /* checksum the plaintext data and hdrlen bytes of the token header */
 139 s32
 140 make_spkm3_checksum(s32 cksumtype, struct xdr_netobj *key, char *header,
 141                     unsigned int hdrlen, struct xdr_buf *body,
 142                     unsigned int body_offset, struct xdr_netobj *cksum)
 143 {
 144         char                            *cksumname;
 145         struct hash_desc                desc; /* XXX add to ctx? */
 146         struct scatterlist              sg[1];
 147         int err;
 148
 149         switch (cksumtype) {
 150                 case CKSUMTYPE_HMAC_MD5:
 151                         cksumname = "hmac(md5)";
 152                         break;
 153                 default:
 154                         dprintk("RPC:       spkm3_make_checksum:"
 155                                         " unsupported checksum %d", cksumtype);
 156                         return GSS_S_FAILURE;
 157         }
 158
 159         if (key->data == NULL || key->len <= 0) return GSS_S_FAILURE;
 160
 161         desc.tfm = crypto_alloc_hash(cksumname, 0, CRYPTO_ALG_ASYNC);
 162         if (IS_ERR(desc.tfm))
 163                 return GSS_S_FAILURE;
 164         cksum->len = crypto_hash_digestsize(desc.tfm);
 165         desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 166
 167         err = crypto_hash_setkey(desc.tfm, key->data, key->len);
 168         if (err)
 169                 goto out;
 170
 171         err = crypto_hash_init(&desc);
 172         if (err)
 173                 goto out;
 174
 175         sg_init_one(sg, header, hdrlen);
 176         crypto_hash_update(&desc, sg, sg->length);
 177
 178         xdr_process_buf(body, body_offset, body->len - body_offset,
 179                         spkm3_checksummer, &desc);
 180         crypto_hash_final(&desc, cksum->data);
 181
 182 out:
 183         crypto_free_hash(desc.tfm);
 184
 185         return err ? GSS_S_FAILURE : 0;
 186 }