source3/libads/sasl_wrapping.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    ads sasl wrapping code
   4    Copyright (C) Stefan Metzmacher 2007
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "includes.h"
  21 #include "ads.h"
  22
  23 void ndr_print_ads_saslwrap_struct(struct ndr_print *ndr, const char *name, const struct ads_saslwrap *r)
  24 {
  25         ndr_print_struct(ndr, name, "saslwrap");
  26         ndr->depth++;
  27         ndr_print_uint16(ndr, "wrap_type", r->wrap_type);
  28 #ifdef HAVE_LDAP_SASL_WRAPPING
  29         ndr_print_ptr(ndr, "sbiod", r->sbiod);
  30 #endif /* HAVE_LDAP_SASL_WRAPPING */
  31         ndr_print_ptr(ndr, "mem_ctx", r->mem_ctx);
  32         ndr_print_ptr(ndr, "wrap_ops", r->wrap_ops);
  33         ndr_print_ptr(ndr, "wrap_private_data", r->wrap_private_data);
  34         ndr_print_struct(ndr, name, "in");
  35         ndr->depth++;
  36         ndr_print_uint32(ndr, "ofs", r->in.ofs);
  37         ndr_print_uint32(ndr, "needed", r->in.needed);
  38         ndr_print_uint32(ndr, "left", r->in.left);
  39         ndr_print_uint32(ndr, "max_wrapped", r->in.max_wrapped);
  40         ndr_print_uint32(ndr, "min_wrapped", r->in.min_wrapped);
  41         ndr_print_uint32(ndr, "size", r->in.size);
  42         ndr_print_array_uint8(ndr, "buf", r->in.buf, r->in.size);
  43         ndr->depth--;
  44         ndr_print_struct(ndr, name, "out");
  45         ndr->depth++;
  46         ndr_print_uint32(ndr, "ofs", r->out.ofs);
  47         ndr_print_uint32(ndr, "left", r->out.left);
  48         ndr_print_uint32(ndr, "max_unwrapped", r->out.max_unwrapped);
  49         ndr_print_uint32(ndr, "sig_size", r->out.sig_size);
  50         ndr_print_uint32(ndr, "size", r->out.size);
  51         ndr_print_array_uint8(ndr, "buf", r->out.buf, r->out.size);
  52         ndr->depth--;
  53 }
  54
  55 #ifdef HAVE_LDAP_SASL_WRAPPING
  56
  57 static int ads_saslwrap_setup(Sockbuf_IO_Desc *sbiod, void *arg)
  58 {
  59         struct ads_saslwrap *wrap = (struct ads_saslwrap *)arg;
  60
  61         wrap->sbiod     = sbiod;
  62
  63         sbiod->sbiod_pvt = wrap;
  64
  65         return 0;
  66 }
  67
  68 static int ads_saslwrap_remove(Sockbuf_IO_Desc *sbiod)
  69 {
  70         return 0;
  71 }
  72
  73 static ber_slen_t ads_saslwrap_prepare_inbuf(struct ads_saslwrap *wrap)
  74 {
  75         wrap->in.ofs    = 0;
  76         wrap->in.needed = 0;
  77         wrap->in.left   = 0;
  78         wrap->in.size   = 4 + wrap->in.min_wrapped;
  79         wrap->in.buf    = talloc_array(wrap->mem_ctx,
  80                                        uint8_t, wrap->in.size);
  81         if (!wrap->in.buf) {
  82                 return -1;
  83         }
  84
  85         return 0;
  86 }
  87
  88 static ber_slen_t ads_saslwrap_grow_inbuf(struct ads_saslwrap *wrap)
  89 {
  90         if (wrap->in.size == (4 + wrap->in.needed)) {
  91                 return 0;
  92         }
  93
  94         wrap->in.size   = 4 + wrap->in.needed;
  95         wrap->in.buf    = talloc_realloc(wrap->mem_ctx,
  96                                          wrap->in.buf,
  97                                          uint8_t, wrap->in.size);
  98         if (!wrap->in.buf) {
  99                 return -1;
 100         }
 101
 102         return 0;
 103 }
 104
 105 static void ads_saslwrap_shrink_inbuf(struct ads_saslwrap *wrap)
 106 {
 107         talloc_free(wrap->in.buf);
 108
 109         wrap->in.buf    = NULL;
 110         wrap->in.size   = 0;
 111         wrap->in.ofs    = 0;
 112         wrap->in.needed = 0;
 113         wrap->in.left   = 0;
 114 }
 115
 116 static ber_slen_t ads_saslwrap_read(Sockbuf_IO_Desc *sbiod,
 117                                     void *buf, ber_len_t len)
 118 {
 119         struct ads_saslwrap *wrap =
 120                         (struct ads_saslwrap *)sbiod->sbiod_pvt;
 121         ber_slen_t ret;
 122
 123         /* If ofs < 4 it means we don't have read the length header yet */
 124         if (wrap->in.ofs < 4) {
 125                 ret = ads_saslwrap_prepare_inbuf(wrap);
 126                 if (ret < 0) return ret;
 127
 128                 ret = LBER_SBIOD_READ_NEXT(sbiod,
 129                                            wrap->in.buf + wrap->in.ofs,
 130                                            4 - wrap->in.ofs);
 131                 if (ret <= 0) return ret;
 132                 wrap->in.ofs += ret;
 133
 134                 if (wrap->in.ofs < 4) goto eagain;
 135
 136                 wrap->in.needed = RIVAL(wrap->in.buf, 0);
 137                 if (wrap->in.needed > wrap->in.max_wrapped) {
 138                         errno = EINVAL;
 139                         return -1;
 140                 }
 141                 if (wrap->in.needed < wrap->in.min_wrapped) {
 142                         errno = EINVAL;
 143                         return -1;
 144                 }
 145
 146                 ret = ads_saslwrap_grow_inbuf(wrap);
 147                 if (ret < 0) return ret;
 148         }
 149
 150         /*
 151          * if there's more data needed from the remote end,
 152          * we need to read more
 153          */
 154         if (wrap->in.needed > 0) {
 155                 ret = LBER_SBIOD_READ_NEXT(sbiod,
 156                                            wrap->in.buf + wrap->in.ofs,
 157                                            wrap->in.needed);
 158                 if (ret <= 0) return ret;
 159                 wrap->in.ofs += ret;
 160                 wrap->in.needed -= ret;
 161
 162                 if (wrap->in.needed > 0) goto eagain;
 163         }
 164
 165         /*
 166          * if we have a complete packet and have not yet unwrapped it
 167          * we need to call the mech specific unwrap() hook
 168          */
 169         if (wrap->in.needed == 0 && wrap->in.left == 0) {
 170                 ADS_STATUS status;
 171                 status = wrap->wrap_ops->unwrap(wrap);
 172                 if (!ADS_ERR_OK(status)) {
 173                         errno = EACCES;
 174                         return -1;
 175                 }
 176         }
 177
 178         /*
 179          * if we have unwrapped data give it to the caller
 180          */
 181         if (wrap->in.left > 0) {
 182                 ret = MIN(wrap->in.left, len);
 183                 memcpy(buf, wrap->in.buf + wrap->in.ofs, ret);
 184                 wrap->in.ofs += ret;
 185                 wrap->in.left -= ret;
 186
 187                 /*
 188                  * if no more is left shrink the inbuf,
 189                  * this will trigger reading a new SASL packet
 190                  * from the remote stream in the next call
 191                  */
 192                 if (wrap->in.left == 0) {
 193                         ads_saslwrap_shrink_inbuf(wrap);
 194                 }
 195
 196                 return ret;
 197         }
 198
 199         /*
 200          * if we don't have anything for the caller yet,
 201          * tell him to ask again
 202          */
 203 eagain:
 204         errno = EAGAIN;
 205         return -1;
 206 }
 207
 208 static ber_slen_t ads_saslwrap_prepare_outbuf(struct ads_saslwrap *wrap,
 209                                               uint32_t len)
 210 {
 211         wrap->out.ofs   = 0;
 212         wrap->out.left  = 0;
 213         wrap->out.size  = 4 + wrap->out.sig_size + len;
 214         wrap->out.buf   = talloc_array(wrap->mem_ctx,
 215                                                uint8_t, wrap->out.size);
 216         if (!wrap->out.buf) {
 217                 return -1;
 218         }
 219
 220         return 0;
 221 }
 222
 223 static void ads_saslwrap_shrink_outbuf(struct ads_saslwrap *wrap)
 224 {
 225         talloc_free(wrap->out.buf);
 226
 227         wrap->out.buf   = NULL;
 228         wrap->out.size  = 0;
 229         wrap->out.ofs   = 0;
 230         wrap->out.left  = 0;
 231 }
 232
 233 static ber_slen_t ads_saslwrap_write(Sockbuf_IO_Desc *sbiod,
 234                                      void *buf, ber_len_t len)
 235 {
 236         struct ads_saslwrap *wrap =
 237                         (struct ads_saslwrap *)sbiod->sbiod_pvt;
 238         ber_slen_t ret, rlen;
 239
 240         /* if the buffer is empty, we need to wrap in incoming buffer */
 241         if (wrap->out.left == 0) {
 242                 ADS_STATUS status;
 243
 244                 if (len == 0) {
 245                         errno = EINVAL;
 246                         return -1;
 247                 }
 248
 249                 rlen = MIN(len, wrap->out.max_unwrapped);
 250
 251                 ret = ads_saslwrap_prepare_outbuf(wrap, rlen);
 252                 if (ret < 0) return ret;
 253
 254                 status = wrap->wrap_ops->wrap(wrap, (uint8_t *)buf, rlen);
 255                 if (!ADS_ERR_OK(status)) {
 256                         errno = EACCES;
 257                         return -1;
 258                 }
 259
 260                 RSIVAL(wrap->out.buf, 0, wrap->out.left - 4);
 261         } else {
 262                 rlen = -1;
 263         }
 264
 265         ret = LBER_SBIOD_WRITE_NEXT(sbiod,
 266                                     wrap->out.buf + wrap->out.ofs,
 267                                     wrap->out.left);
 268         if (ret <= 0) return ret;
 269         wrap->out.ofs += ret;
 270         wrap->out.left -= ret;
 271
 272         if (wrap->out.left == 0) {
 273                 ads_saslwrap_shrink_outbuf(wrap);
 274         }
 275
 276         if (rlen > 0) return rlen;
 277
 278         errno = EAGAIN;
 279         return -1;
 280 }
 281
 282 static int ads_saslwrap_ctrl(Sockbuf_IO_Desc *sbiod, int opt, void *arg)
 283 {
 284         struct ads_saslwrap *wrap =
 285                         (struct ads_saslwrap *)sbiod->sbiod_pvt;
 286         int ret;
 287
 288         switch (opt) {
 289         case LBER_SB_OPT_DATA_READY:
 290                 if (wrap->in.left > 0) {
 291                         return 1;
 292                 }
 293                 ret = LBER_SBIOD_CTRL_NEXT(sbiod, opt, arg);
 294                 break;
 295         default:
 296                 ret = LBER_SBIOD_CTRL_NEXT(sbiod, opt, arg);
 297                 break;
 298         }
 299
 300         return ret;
 301 }
 302
 303 static int ads_saslwrap_close(Sockbuf_IO_Desc *sbiod)
 304 {
 305         return 0;
 306 }
 307
 308 static const Sockbuf_IO ads_saslwrap_sockbuf_io = {
 309         ads_saslwrap_setup,     /* sbi_setup */
 310         ads_saslwrap_remove,    /* sbi_remove */
 311         ads_saslwrap_ctrl,      /* sbi_ctrl */
 312         ads_saslwrap_read,      /* sbi_read */
 313         ads_saslwrap_write,     /* sbi_write */
 314         ads_saslwrap_close      /* sbi_close */
 315 };
 316
 317 ADS_STATUS ads_setup_sasl_wrapping(struct ads_saslwrap *wrap, LDAP *ld,
 318                                    const struct ads_saslwrap_ops *ops,
 319                                    void *private_data)
 320 {
 321         ADS_STATUS status;
 322         Sockbuf *sb;
 323         Sockbuf_IO *io = discard_const_p(Sockbuf_IO, &ads_saslwrap_sockbuf_io);
 324         int rc;
 325
 326         rc = ldap_get_option(ld, LDAP_OPT_SOCKBUF, &sb);
 327         status = ADS_ERROR_LDAP(rc);
 328         if (!ADS_ERR_OK(status)) {
 329                 return status;
 330         }
 331
 332         /* setup the real wrapping callbacks */
 333         rc = ber_sockbuf_add_io(sb, io, LBER_SBIOD_LEVEL_TRANSPORT, wrap);
 334         status = ADS_ERROR_LDAP(rc);
 335         if (!ADS_ERR_OK(status)) {
 336                 return status;
 337         }
 338
 339         wrap->wrap_ops          = ops;
 340         wrap->wrap_private_data = private_data;
 341
 342         return ADS_SUCCESS;
 343 }
 344 #else
 345 ADS_STATUS ads_setup_sasl_wrapping(struct ads_saslwrap *wrap, LDAP *ld,
 346                                    const struct ads_saslwrap_ops *ops,
 347                                    void *private_data)
 348 {
 349         return ADS_ERROR_NT(NT_STATUS_NOT_SUPPORTED);
 350 }
 351 #endif /* HAVE_LDAP_SASL_WRAPPING */