source/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
  22 #ifdef HAVE_LDAP_SASL_WRAPPING
  23
  24 static int ads_saslwrap_setup(Sockbuf_IO_Desc *sbiod, void *arg)
  25 {
  26         ADS_STRUCT *ads = (ADS_STRUCT *)arg;
  27
  28         ads->ldap.sbiod = sbiod;
  29
  30         sbiod->sbiod_pvt = ads;
  31
  32         return 0;
  33 }
  34
  35 static int ads_saslwrap_remove(Sockbuf_IO_Desc *sbiod)
  36 {
  37         return 0;
  38 }
  39
  40 static ber_slen_t ads_saslwrap_prepare_inbuf(ADS_STRUCT *ads)
  41 {
  42         ads->ldap.in.ofs        = 0;
  43         ads->ldap.in.needed     = 0;
  44         ads->ldap.in.left       = 0;
  45         ads->ldap.in.size       = 4 + ads->ldap.in.min_wrapped;
  46         ads->ldap.in.buf        = talloc_array(ads->ldap.mem_ctx,
  47                                                uint8, ads->ldap.in.size);
  48         if (!ads->ldap.in.buf) {
  49                 return -1;
  50         }
  51
  52         return 0;
  53 }
  54
  55 static ber_slen_t ads_saslwrap_grow_inbuf(ADS_STRUCT *ads)
  56 {
  57         if (ads->ldap.in.size == (4 + ads->ldap.in.needed)) {
  58                 return 0;
  59         }
  60
  61         ads->ldap.in.size       = 4 + ads->ldap.in.needed;
  62         ads->ldap.in.buf        = talloc_realloc(ads->ldap.mem_ctx,
  63                                                  ads->ldap.in.buf,
  64                                                  uint8, ads->ldap.in.size);
  65         if (!ads->ldap.in.buf) {
  66                 return -1;
  67         }
  68
  69         return 0;
  70 }
  71
  72 static void ads_saslwrap_shrink_inbuf(ADS_STRUCT *ads)
  73 {
  74         talloc_free(ads->ldap.in.buf);
  75
  76         ads->ldap.in.buf        = NULL;
  77         ads->ldap.in.size       = 0;
  78         ads->ldap.in.ofs        = 0;
  79         ads->ldap.in.needed     = 0;
  80         ads->ldap.in.left       = 0;
  81 }
  82
  83 static ber_slen_t ads_saslwrap_read(Sockbuf_IO_Desc *sbiod, void *buf, ber_len_t len)
  84 {
  85         ADS_STRUCT *ads = (ADS_STRUCT *)sbiod->sbiod_pvt;
  86         ber_slen_t ret;
  87
  88         /* If ofs < 4 it means we don't have read the length header yet */
  89         if (ads->ldap.in.ofs < 4) {
  90                 ret = ads_saslwrap_prepare_inbuf(ads);
  91                 if (ret < 0) return ret;
  92
  93                 ret = LBER_SBIOD_READ_NEXT(sbiod,
  94                                            ads->ldap.in.buf + ads->ldap.in.ofs,
  95                                            4 - ads->ldap.in.ofs);
  96                 if (ret <= 0) return ret;
  97                 ads->ldap.in.ofs += ret;
  98
  99                 if (ads->ldap.in.ofs < 4) goto eagain;
 100
 101                 ads->ldap.in.needed = RIVAL(ads->ldap.in.buf, 0);
 102                 if (ads->ldap.in.needed > ads->ldap.in.max_wrapped) {
 103                         errno = EINVAL;
 104                         return -1;
 105                 }
 106                 if (ads->ldap.in.needed < ads->ldap.in.min_wrapped) {
 107                         errno = EINVAL;
 108                         return -1;
 109                 }
 110
 111                 ret = ads_saslwrap_grow_inbuf(ads);
 112                 if (ret < 0) return ret;
 113         }
 114
 115         /*
 116          * if there's more data needed from the remote end,
 117          * we need to read more
 118          */
 119         if (ads->ldap.in.needed > 0) {
 120                 ret = LBER_SBIOD_READ_NEXT(sbiod,
 121                                            ads->ldap.in.buf + ads->ldap.in.ofs,
 122                                            ads->ldap.in.needed);
 123                 if (ret <= 0) return ret;
 124                 ads->ldap.in.ofs += ret;
 125                 ads->ldap.in.needed -= ret;
 126
 127                 if (ads->ldap.in.needed > 0) goto eagain;
 128         }
 129
 130         /*
 131          * if we have a complete packet and have not yet unwrapped it
 132          * we need to call the mech specific unwrap() hook
 133          */
 134         if (ads->ldap.in.needed == 0 && ads->ldap.in.left == 0) {
 135                 ADS_STATUS status;
 136                 status = ads->ldap.wrap_ops->unwrap(ads);
 137                 if (!ADS_ERR_OK(status)) {
 138                         errno = EACCES;
 139                         return -1;
 140                 }
 141         }
 142
 143         /*
 144          * if we have unwrapped data give it to the caller
 145          */
 146         if (ads->ldap.in.left > 0) {
 147                 ret = MIN(ads->ldap.in.left, len);
 148                 memcpy(buf, ads->ldap.in.buf + ads->ldap.in.ofs, ret);
 149                 ads->ldap.in.ofs += ret;
 150                 ads->ldap.in.left -= ret;
 151
 152                 /*
 153                  * if no more is left shrink the inbuf,
 154                  * this will trigger reading a new SASL packet
 155                  * from the remote stream in the next call
 156                  */
 157                 if (ads->ldap.in.left == 0) {
 158                         ads_saslwrap_shrink_inbuf(ads);
 159                 }
 160
 161                 return ret;
 162         }
 163
 164         /*
 165          * if we don't have anything for the caller yet,
 166          * tell him to ask again
 167          */
 168 eagain:
 169         errno = EAGAIN;
 170         return -1;
 171 }
 172
 173 static ber_slen_t ads_saslwrap_prepare_outbuf(ADS_STRUCT *ads, uint32 len)
 174 {
 175         ads->ldap.out.ofs       = 0;
 176         ads->ldap.out.left      = 0;
 177         ads->ldap.out.size      = 4 + ads->ldap.out.sig_size + len;
 178         ads->ldap.out.buf       = talloc_array(ads->ldap.mem_ctx,
 179                                                uint8, ads->ldap.out.size);
 180         if (!ads->ldap.out.buf) {
 181                 return -1;
 182         }
 183
 184         return 0;
 185 }
 186
 187 static void ads_saslwrap_shrink_outbuf(ADS_STRUCT *ads)
 188 {
 189         talloc_free(ads->ldap.out.buf);
 190
 191         ads->ldap.out.buf       = NULL;
 192         ads->ldap.out.size      = 0;
 193         ads->ldap.out.ofs       = 0;
 194         ads->ldap.out.left      = 0;
 195 }
 196
 197 static ber_slen_t ads_saslwrap_write(Sockbuf_IO_Desc *sbiod, void *buf, ber_len_t len)
 198 {
 199         ADS_STRUCT *ads = (ADS_STRUCT *)sbiod->sbiod_pvt;
 200         ber_slen_t ret, rlen;
 201
 202         /* if the buffer is empty, we need to wrap in incoming buffer */
 203         if (ads->ldap.out.left == 0) {
 204                 ADS_STATUS status;
 205
 206                 if (len == 0) {
 207                         errno = EINVAL;
 208                         return -1;
 209                 }
 210
 211                 rlen = MIN(len, ads->ldap.out.max_unwrapped);
 212
 213                 ret = ads_saslwrap_prepare_outbuf(ads, rlen);
 214                 if (ret < 0) return ret;
 215
 216                 status = ads->ldap.wrap_ops->wrap(ads, (uint8 *)buf, rlen);
 217                 if (!ADS_ERR_OK(status)) {
 218                         errno = EACCES;
 219                         return -1;
 220                 }
 221
 222                 RSIVAL(ads->ldap.out.buf, 0, ads->ldap.out.left - 4);
 223         } else {
 224                 rlen = -1;
 225         }
 226
 227         ret = LBER_SBIOD_WRITE_NEXT(sbiod,
 228                                     ads->ldap.out.buf + ads->ldap.out.ofs,
 229                                     ads->ldap.out.left);
 230         if (ret <= 0) return ret;
 231         ads->ldap.out.ofs += ret;
 232         ads->ldap.out.left -= ret;
 233
 234         if (ads->ldap.out.left == 0) {
 235                 ads_saslwrap_shrink_outbuf(ads);
 236         }
 237
 238         if (rlen > 0) return rlen;
 239
 240         errno = EAGAIN;
 241         return -1;
 242 }
 243
 244 static int ads_saslwrap_ctrl(Sockbuf_IO_Desc *sbiod, int opt, void *arg)
 245 {
 246         ADS_STRUCT *ads = (ADS_STRUCT *)sbiod->sbiod_pvt;
 247         int ret;
 248
 249         switch (opt) {
 250         case LBER_SB_OPT_DATA_READY:
 251                 if (ads->ldap.in.left > 0) {
 252                         return 1;
 253                 }
 254                 ret = LBER_SBIOD_CTRL_NEXT(sbiod, opt, arg);
 255                 break;
 256         default:
 257                 ret = LBER_SBIOD_CTRL_NEXT(sbiod, opt, arg);
 258                 break;
 259         }
 260
 261         return ret;
 262 }
 263
 264 static int ads_saslwrap_close(Sockbuf_IO_Desc *sbiod)
 265 {
 266         return 0;
 267 }
 268
 269 static const Sockbuf_IO ads_saslwrap_sockbuf_io = {
 270         ads_saslwrap_setup,     /* sbi_setup */
 271         ads_saslwrap_remove,    /* sbi_remove */
 272         ads_saslwrap_ctrl,      /* sbi_ctrl */
 273         ads_saslwrap_read,      /* sbi_read */
 274         ads_saslwrap_write,     /* sbi_write */
 275         ads_saslwrap_close      /* sbi_close */
 276 };
 277
 278 ADS_STATUS ads_setup_sasl_wrapping(ADS_STRUCT *ads,
 279                                    const struct ads_saslwrap_ops *ops,
 280                                    void *private_data)
 281 {
 282         ADS_STATUS status;
 283         Sockbuf *sb;
 284         Sockbuf_IO *io = discard_const_p(Sockbuf_IO, &ads_saslwrap_sockbuf_io);
 285         int rc;
 286
 287         rc = ldap_get_option(ads->ldap.ld, LDAP_OPT_SOCKBUF, &sb);
 288         status = ADS_ERROR_LDAP(rc);
 289         if (!ADS_ERR_OK(status)) {
 290                 return status;
 291         }
 292
 293         /* setup the real wrapping callbacks */
 294         rc = ber_sockbuf_add_io(sb, io, LBER_SBIOD_LEVEL_TRANSPORT, ads);
 295         status = ADS_ERROR_LDAP(rc);
 296         if (!ADS_ERR_OK(status)) {
 297                 return status;
 298         }
 299
 300         ads->ldap.wrap_ops              = ops;
 301         ads->ldap.wrap_private_data     = private_data;
 302
 303         return ADS_SUCCESS;
 304 }
 305 #else
 306 ADS_STATUS ads_setup_sasl_wrapping(ADS_STRUCT *ads,
 307                                    const struct ads_saslwrap_ops *ops,
 308                                    void *private_data)
 309 {
 310         return ADS_ERROR_NT(NT_STATUS_NOT_SUPPORTED);
 311 }
 312 #endif /* HAVE_LDAP_SASL_WRAPPING */