sbin/dhclient/privsep.c

   1 /*      $OpenBSD: privsep.c,v 1.14 2007/02/15 15:22:27 stevesk Exp $ */
   2 /*      $DragonFly: src/sbin/dhclient/privsep.c,v 1.1 2008/08/30 16:07:58 hasso Exp $   */
   3
   4 /*
   5  * Copyright (c) 2004 Henning Brauer <henning@openbsd.org>
   6  *
   7  * Permission to use, copy, modify, and distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  15  * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER IN
  16  * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  17  * OF OR IN CONNECTION WITH THE USE, ABUSE OR PERFORMANCE OF THIS SOFTWARE.
  18  */
  19
  20 #include "dhcpd.h"
  21 #include "privsep.h"
  22
  23 struct buf *
  24 buf_open(size_t len)
  25 {
  26         struct buf      *buf;
  27
  28         if ((buf = calloc(1, sizeof(struct buf))) == NULL)
  29                 error("buf_open: %m");
  30         if ((buf->buf = malloc(len)) == NULL) {
  31                 free(buf);
  32                 error("buf_open: %m");
  33         }
  34         buf->size = len;
  35
  36         return (buf);
  37 }
  38
  39 void
  40 buf_add(struct buf *buf, void *data, size_t len)
  41 {
  42         if (len == 0)
  43                 return;
  44
  45         if (buf->wpos + len > buf->size)
  46                 error("buf_add: %m");
  47
  48         memcpy(buf->buf + buf->wpos, data, len);
  49         buf->wpos += len;
  50 }
  51
  52 void
  53 buf_close(int sock, struct buf *buf)
  54 {
  55         ssize_t n;
  56
  57         do {
  58                 n = write(sock, buf->buf + buf->rpos, buf->size - buf->rpos);
  59                 if (n == 0)                     /* connection closed */
  60                         error("buf_close (connection closed)");
  61                 if (n != -1 && n < buf->size - buf->rpos)
  62                         error("buf_close (short write): %m");
  63
  64         } while (n == -1 && (errno == EAGAIN || errno == EINTR));
  65
  66         if (n == -1)
  67                 error("buf_close: %m");
  68
  69         free(buf->buf);
  70         free(buf);
  71 }
  72
  73 void
  74 buf_read(int sock, void *buf, size_t nbytes)
  75 {
  76         ssize_t n;
  77
  78         do {
  79                 n = read(sock, buf, nbytes);
  80                 if (n == 0) {                   /* connection closed */
  81                         debug("buf_read (connection closed)");
  82                         exit(1);
  83                 }
  84                 if (n != -1 && n < nbytes)
  85                         error("buf_read (short read): %m");
  86         } while (n == -1 && (errno == EINTR || errno == EAGAIN));
  87
  88         if (n == -1)
  89                 error("buf_read: %m");
  90 }
  91
  92 void
  93 dispatch_imsg(int fd)
  94 {
  95         struct imsg_hdr          hdr;
  96         char                    *medium, *reason, *filename,
  97                                 *servername, *prefix;
  98         size_t                   medium_len, reason_len, filename_len,
  99                                  servername_len, prefix_len, totlen;
 100         struct client_lease      lease;
 101         int                      ret, i, optlen;
 102         struct buf              *buf;
 103
 104         buf_read(fd, &hdr, sizeof(hdr));
 105
 106         switch (hdr.code) {
 107         case IMSG_SCRIPT_INIT:
 108                 if (hdr.len < sizeof(hdr) + sizeof(size_t))
 109                         error("corrupted message received");
 110                 buf_read(fd, &medium_len, sizeof(medium_len));
 111                 if (hdr.len < medium_len + sizeof(size_t) + sizeof(hdr)
 112                     + sizeof(size_t) || medium_len == SIZE_T_MAX)
 113                         error("corrupted message received");
 114                 if (medium_len > 0) {
 115                         if ((medium = calloc(1, medium_len + 1)) == NULL)
 116                                 error("%m");
 117                         buf_read(fd, medium, medium_len);
 118                 } else
 119                         medium = NULL;
 120
 121                 buf_read(fd, &reason_len, sizeof(reason_len));
 122                 if (hdr.len < medium_len + reason_len + sizeof(hdr) ||
 123                     reason_len == SIZE_T_MAX)
 124                         error("corrupted message received");
 125                 if (reason_len > 0) {
 126                         if ((reason = calloc(1, reason_len + 1)) == NULL)
 127                                 error("%m");
 128                         buf_read(fd, reason, reason_len);
 129                 } else
 130                         reason = NULL;
 131
 132                 priv_script_init(reason, medium);
 133                 free(reason);
 134                 free(medium);
 135                 break;
 136         case IMSG_SCRIPT_WRITE_PARAMS:
 137                 bzero(&lease, sizeof lease);
 138                 totlen = sizeof(hdr) + sizeof(lease) + sizeof(size_t);
 139                 if (hdr.len < totlen)
 140                         error("corrupted message received");
 141                 buf_read(fd, &lease, sizeof(lease));
 142
 143                 buf_read(fd, &filename_len, sizeof(filename_len));
 144                 totlen += filename_len + sizeof(size_t);
 145                 if (hdr.len < totlen || filename_len == SIZE_T_MAX)
 146                         error("corrupted message received");
 147                 if (filename_len > 0) {
 148                         if ((filename = calloc(1, filename_len + 1)) == NULL)
 149                                 error("%m");
 150                         buf_read(fd, filename, filename_len);
 151                 } else
 152                         filename = NULL;
 153
 154                 buf_read(fd, &servername_len, sizeof(servername_len));
 155                 totlen += servername_len + sizeof(size_t);
 156                 if (hdr.len < totlen || servername_len == SIZE_T_MAX)
 157                         error("corrupted message received");
 158                 if (servername_len > 0) {
 159                         if ((servername =
 160                             calloc(1, servername_len + 1)) == NULL)
 161                                 error("%m");
 162                         buf_read(fd, servername, servername_len);
 163                 } else
 164                         servername = NULL;
 165
 166                 buf_read(fd, &prefix_len, sizeof(prefix_len));
 167                 totlen += prefix_len;
 168                 if (hdr.len < totlen || prefix_len == SIZE_T_MAX)
 169                         error("corrupted message received");
 170                 if (prefix_len > 0) {
 171                         if ((prefix = calloc(1, prefix_len + 1)) == NULL)
 172                                 error("%m");
 173                         buf_read(fd, prefix, prefix_len);
 174                 } else
 175                         prefix = NULL;
 176
 177                 for (i = 0; i < 256; i++) {
 178                         totlen += sizeof(optlen);
 179                         if (hdr.len < totlen)
 180                                 error("corrupted message received");
 181                         buf_read(fd, &optlen, sizeof(optlen));
 182                         lease.options[i].data = NULL;
 183                         lease.options[i].len = optlen;
 184                         if (optlen > 0) {
 185                                 totlen += optlen;
 186                                 if (hdr.len < totlen || optlen == SIZE_T_MAX)
 187                                         error("corrupted message received");
 188                                 lease.options[i].data =
 189                                     calloc(1, optlen + 1);
 190                                 if (lease.options[i].data == NULL)
 191                                     error("%m");
 192                                 buf_read(fd, lease.options[i].data, optlen);
 193                         }
 194                 }
 195                 lease.server_name = servername;
 196                 lease.filename = filename;
 197
 198                 priv_script_write_params(prefix, &lease);
 199
 200                 free(servername);
 201                 free(filename);
 202                 free(prefix);
 203                 for (i = 0; i < 256; i++)
 204                         if (lease.options[i].len > 0)
 205                                 free(lease.options[i].data);
 206                 break;
 207         case IMSG_SCRIPT_GO:
 208                 if (hdr.len != sizeof(hdr))
 209                         error("corrupted message received");
 210
 211                 ret = priv_script_go();
 212
 213                 hdr.code = IMSG_SCRIPT_GO_RET;
 214                 hdr.len = sizeof(struct imsg_hdr) + sizeof(int);
 215                 if ((buf = buf_open(hdr.len)) == NULL)
 216                         error("buf_open: %m");
 217                 buf_add(buf, &hdr, sizeof(hdr));
 218                 buf_add(buf, &ret, sizeof(ret));
 219                 buf_close(fd, buf);
 220                 break;
 221         default:
 222                 error("received unknown message, code %d", hdr.code);
 223         }
 224 }