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/slab.h>
  38 #include <linux/jiffies.h>
  39 #include <linux/sunrpc/gss_spkm3.h>
  40 #include <linux/random.h>
  41 #include <linux/crypto.h>
  42 #include <linux/pagemap.h>
  43 #include <linux/scatterlist.h>
  44 #include <linux/sunrpc/xdr.h>
  45
  46 #ifdef RPC_DEBUG
  47 # define RPCDBG_FACILITY        RPCDBG_AUTH
  48 #endif
  49
  50 const struct xdr_netobj hmac_md5_oid = { 8, "\x2B\x06\x01\x05\x05\x08\x01\x01"};
  51 const struct xdr_netobj cast5_cbc_oid = {9, "\x2A\x86\x48\x86\xF6\x7D\x07\x42\x0A"};
  52
  53 /*
  54  * spkm3_make_token()
  55  *
  56  * Only SPKM_MIC_TOK with md5 intg-alg is supported
  57  */
  58
  59 u32
  60 spkm3_make_token(struct spkm3_ctx *ctx,
  61                    struct xdr_buf * text, struct xdr_netobj * token,
  62                    int toktype)
  63 {
  64         s32                     checksum_type;
  65         char                    tokhdrbuf[25];
  66         char                    cksumdata[16];
  67         struct xdr_netobj       md5cksum = {.len = 0, .data = cksumdata};
  68         struct xdr_netobj       mic_hdr = {.len = 0, .data = tokhdrbuf};
  69         int                     tokenlen = 0;
  70         unsigned char           *ptr;
  71         s32                     now;
  72         int                     ctxelen = 0, ctxzbit = 0;
  73         int                     md5elen = 0, md5zbit = 0;
  74
  75         now = jiffies;
  76
  77         if (ctx->ctx_id.len != 16) {
  78                 dprintk("RPC:       spkm3_make_token BAD ctx_id.len %d\n",
  79                                 ctx->ctx_id.len);
  80                 goto out_err;
  81         }
  82
  83         if (!g_OID_equal(&ctx->intg_alg, &hmac_md5_oid)) {
  84                 dprintk("RPC:       gss_spkm3_seal: unsupported I-ALG "
  85                                 "algorithm.  only support hmac-md5 I-ALG.\n");
  86                 goto out_err;
  87         } else
  88                 checksum_type = CKSUMTYPE_HMAC_MD5;
  89
  90         if (!g_OID_equal(&ctx->conf_alg, &cast5_cbc_oid)) {
  91                 dprintk("RPC:       gss_spkm3_seal: unsupported C-ALG "
  92                                 "algorithm\n");
  93                 goto out_err;
  94         }
  95
  96         if (toktype == SPKM_MIC_TOK) {
  97                 /* Calculate checksum over the mic-header */
  98                 asn1_bitstring_len(&ctx->ctx_id, &ctxelen, &ctxzbit);
  99                 spkm3_mic_header(&mic_hdr.data, &mic_hdr.len, ctx->ctx_id.data,
 100                                 ctxelen, ctxzbit);
 101                 if (make_spkm3_checksum(checksum_type, &ctx->derived_integ_key,
 102                                         (char *)mic_hdr.data, mic_hdr.len,
 103                                         text, 0, &md5cksum))
 104                         goto out_err;
 105
 106                 asn1_bitstring_len(&md5cksum, &md5elen, &md5zbit);
 107                 tokenlen = 10 + ctxelen + 1 + md5elen + 1;
 108
 109                 /* Create token header using generic routines */
 110                 token->len = g_token_size(&ctx->mech_used, tokenlen);
 111
 112                 ptr = token->data;
 113                 g_make_token_header(&ctx->mech_used, tokenlen, &ptr);
 114
 115                 spkm3_make_mic_token(&ptr, tokenlen, &mic_hdr, &md5cksum, md5elen, md5zbit);
 116         } else if (toktype == SPKM_WRAP_TOK) { /* Not Supported */
 117                 dprintk("RPC:       gss_spkm3_seal: SPKM_WRAP_TOK "
 118                                 "not supported\n");
 119                 goto out_err;
 120         }
 121
 122         /* XXX need to implement sequence numbers, and ctx->expired */
 123
 124         return  GSS_S_COMPLETE;
 125 out_err:
 126         token->data = NULL;
 127         token->len = 0;
 128         return GSS_S_FAILURE;
 129 }
 130
 131 static int
 132 spkm3_checksummer(struct scatterlist *sg, void *data)
 133 {
 134         struct hash_desc *desc = data;
 135
 136         return crypto_hash_update(desc, sg, sg->length);
 137 }
 138
 139 /* checksum the plaintext data and hdrlen bytes of the token header */
 140 s32
 141 make_spkm3_checksum(s32 cksumtype, struct xdr_netobj *key, char *header,
 142                     unsigned int hdrlen, struct xdr_buf *body,
 143                     unsigned int body_offset, struct xdr_netobj *cksum)
 144 {
 145         char                            *cksumname;
 146         struct hash_desc                desc; /* XXX add to ctx? */
 147         struct scatterlist              sg[1];
 148         int err;
 149
 150         switch (cksumtype) {
 151                 case CKSUMTYPE_HMAC_MD5:
 152                         cksumname = "hmac(md5)";
 153                         break;
 154                 default:
 155                         dprintk("RPC:       spkm3_make_checksum:"
 156                                         " unsupported checksum %d", cksumtype);
 157                         return GSS_S_FAILURE;
 158         }
 159
 160         if (key->data == NULL || key->len <= 0) return GSS_S_FAILURE;
 161
 162         desc.tfm = crypto_alloc_hash(cksumname, 0, CRYPTO_ALG_ASYNC);
 163         if (IS_ERR(desc.tfm))
 164                 return GSS_S_FAILURE;
 165         cksum->len = crypto_hash_digestsize(desc.tfm);
 166         desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 167
 168         err = crypto_hash_setkey(desc.tfm, key->data, key->len);
 169         if (err)
 170                 goto out;
 171
 172         err = crypto_hash_init(&desc);
 173         if (err)
 174                 goto out;
 175
 176         sg_init_one(sg, header, hdrlen);
 177         crypto_hash_update(&desc, sg, sg->length);
 178
 179         xdr_process_buf(body, body_offset, body->len - body_offset,
 180                         spkm3_checksummer, &desc);
 181         crypto_hash_final(&desc, cksum->data);
 182
 183 out:
 184         crypto_free_hash(desc.tfm);
 185
 186         return err ? GSS_S_FAILURE : 0;
 187 }