authd/dns.c

   1 /* authd/dns.h - header for authd DNS functions
   2  * Copyright (c) 2016 William Pitcock <nenolod@dereferenced.org>
   3  *
   4  * Permission to use, copy, modify, and/or distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice is present in all copies.
   7  *
   8  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   9  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  10  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  11  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
  12  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  13  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  14  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  15  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  16  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  17  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  18  * POSSIBILITY OF SUCH DAMAGE.
  19  */
  20
  21 #include "authd.h"
  22 #include "dns.h"
  23
  24 static void
  25 submit_dns_answer(void *userdata, struct DNSReply *reply)
  26 {
  27         struct dns_request *req = userdata;
  28         char response[64] = "*";
  29         char status = 'E';
  30
  31         if (reply == NULL)
  32         {
  33                 rb_helper_write(authd_helper, "E %s E %c *", req->reqid, req->type);
  34                 goto cleanup;
  35         }
  36
  37         switch (req->type)
  38         {
  39         case '4':
  40                 if (GET_SS_FAMILY(&reply->addr) == AF_INET)
  41                 {
  42                         status = 'O';
  43                         rb_inet_ntop_sock((struct sockaddr *) &reply->addr, response, sizeof(response));
  44                 }
  45                 break;
  46 #ifdef RB_IPV6
  47         case '6':
  48                 if (GET_SS_FAMILY(&reply->addr) == AF_INET6)
  49                 {
  50                         char tmpres[63];
  51                         rb_inet_ntop_sock((struct sockaddr *) &reply->addr, tmpres, sizeof(tmpres));
  52
  53                         if (*tmpres == ':')
  54                         {
  55                                 rb_strlcpy(response, "0", sizeof(response));
  56                                 rb_strlcat(response, tmpres, sizeof(response));
  57                         }
  58                         else
  59                                 rb_strlcpy(response, tmpres, sizeof(response));
  60
  61                         status = 'O';
  62                 }
  63                 break;
  64 #endif
  65         case 'R':
  66                 {
  67                         struct sockaddr_in *ip, *ip_fwd;
  68                         ip = (struct sockaddr_in *) &req->addr;
  69                         ip_fwd = (struct sockaddr_in *) &reply->addr;
  70
  71                         if(ip->sin_addr.s_addr == ip_fwd->sin_addr.s_addr && strlen(reply->h_name) < 63)
  72                         {
  73                                 rb_strlcpy(response, reply->h_name, sizeof(response));
  74                                 status = 'O';
  75                         }
  76                 }
  77                 break;
  78 #ifdef RB_IPV6
  79         case 'S':
  80                 {
  81                         struct sockaddr_in6 *ip, *ip_fwd;
  82                         ip = (struct sockaddr_in6 *) &req->addr;
  83                         ip_fwd = (struct sockaddr_in6 *) &reply->addr;
  84
  85                         if(memcmp(&ip->sin6_addr, &ip_fwd->sin6_addr, sizeof(struct in6_addr)) == 0 && strlen(reply->h_name) < 63)
  86                         {
  87                                 rb_strlcpy(response, reply->h_name, sizeof(response));
  88                                 status = 'O';
  89                         }
  90                 }
  91                 break;
  92 #endif
  93         default:
  94                 exit(7);
  95         }
  96
  97         rb_helper_write(authd_helper, "E %s %c %c %s", req->reqid, status, req->type, response);
  98 cleanup:
  99         rb_free(req);
 100 }
 101
 102 void
 103 resolve_dns(int parc, char *parv[])
 104 {
 105         struct dns_request *req;
 106         char *requestid = parv[1];
 107         char *qtype = parv[2];
 108         char *rec = parv[3];
 109         int type;
 110
 111         req = rb_malloc(sizeof(*req));
 112         rb_strlcpy(req->reqid, requestid, sizeof(req->reqid));
 113         req->type = *qtype;
 114
 115         switch (req->type)
 116         {
 117         case '4':
 118                 type = T_A;
 119                 break;
 120         case '6':
 121                 type = T_AAAA;
 122                 break;
 123         case 'R':
 124         case 'S':
 125                 if(!rb_inet_pton_sock(rec, (struct sockaddr *) &req->addr))
 126                         exit(6);
 127                 type = T_PTR;
 128                 break;
 129         }
 130
 131         req->query.ptr = req;
 132         req->query.callback = submit_dns_answer;
 133
 134         if (type != T_PTR)
 135                 gethost_byname_type(rec, &req->query, type);
 136         else
 137                 gethost_byaddr(&req->addr, &req->query);
 138 }