mDNSMacOSX/uDNSPathEvaluation.c

   1 /*
   2  * Copyright (c) 2013-2020 Apple Inc. All rights reserved.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     https://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include "mDNSMacOSX.h"
  18 #include <libproc.h>
  19 #include <nw/private.h>
  20
  21 #include "dns_sd_internal.h"
  22
  23 #if MDNSRESPONDER_SUPPORTS(APPLE, QUERIER)
  24 #include "QuerierSupport.h"
  25 #endif
  26
  27 #define _nw_forget(PTR)         \
  28     do                          \
  29     {                           \
  30         if (*(PTR))             \
  31         {                       \
  32             nw_release(*(PTR)); \
  33             *(PTR) = NULL;      \
  34         }                       \
  35     } while (0)
  36
  37 //Gets the DNSPolicy from NW PATH EVALUATOR
  38 mDNSexport void mDNSPlatformGetDNSRoutePolicy(DNSQuestion *q)
  39 {
  40     nw_endpoint_t host = NULL;
  41     nw_parameters_t parameters = NULL;
  42     nw_path_evaluator_t evaluator = NULL;
  43     nw_path_t path = NULL;
  44     mDNSBool isBlocked = mDNSfalse;
  45     q->ServiceID = -1; // initialize the ServiceID to default value of -1
  46
  47     // Return for non-unicast DNS queries, or invalid PID.
  48     if (mDNSOpaque16IsZero(q->TargetQID) || (q->pid < 0))
  49     {
  50         goto exit;
  51     }
  52
  53     mDNSs32 service_id;
  54     mDNSu32 client_ifindex, dnspol_ifindex;
  55     int retval;
  56     struct proc_uniqidentifierinfo info;
  57     mDNSBool isUUIDSet;
  58
  59     char unenc_name[MAX_ESCAPED_DOMAIN_NAME];
  60     ConvertDomainNameToCString(&q->qname, unenc_name);
  61
  62     host = nw_endpoint_create_host(unenc_name, "0");
  63     if (host == NULL)
  64     {
  65         LogRedact(MDNS_LOG_CATEGORY_DEFAULT, MDNS_LOG_ERROR,
  66             "[Q%u] mDNSPlatformGetDNSRoutePolicy: Query for " PRI_DM_NAME " (" PUB_S "), PID[%d], EUID[%d], ServiceID[%d]"
  67             " host is NULL",
  68             mDNSVal16(q->TargetQID), DM_NAME_PARAM(&q->qname), DNSTypeName(q->qtype), q->pid, q->euid, q->ServiceID);
  69         goto exit;
  70     }
  71     parameters = nw_parameters_create();
  72     if (parameters == NULL)
  73     {
  74         LogRedact(MDNS_LOG_CATEGORY_DEFAULT, MDNS_LOG_ERROR,
  75             "[Q%u] mDNSPlatformGetDNSRoutePolicy: Query for " PRI_DM_NAME " (" PUB_S "), PID[%d], EUID[%d], ServiceID[%d]"
  76             " parameters is NULL",
  77             mDNSVal16(q->TargetQID), DM_NAME_PARAM(&q->qname), DNSTypeName(q->qtype), q->pid, q->euid, q->ServiceID);
  78         goto exit;
  79     }
  80 #if TARGET_OS_WATCH
  81     static xpc_object_t prohibited_interface_subtypes = NULL;
  82     // Companion interface on watchOS does not support DNS, so we don't want path evalution to return it to us.
  83     if (prohibited_interface_subtypes == NULL)
  84     {
  85         prohibited_interface_subtypes = xpc_array_create(NULL, 0);
  86         if (prohibited_interface_subtypes != NULL)
  87         {
  88             xpc_array_set_uint64(prohibited_interface_subtypes, XPC_ARRAY_APPEND, nw_interface_subtype_companion);
  89         }
  90     }
  91     if (prohibited_interface_subtypes == NULL)
  92     {
  93         LogRedact(MDNS_LOG_CATEGORY_UDNS, MDNS_LOG_ERROR,
  94                   "mDNSPlatformGetDNSRoutePolicy: DNS Route Policy: prohibited_interface_subtypes returned by xpc_array_create() is NULL");
  95     }
  96     else
  97     {
  98         nw_parameters_set_prohibited_interface_subtypes(parameters, prohibited_interface_subtypes);
  99     }
 100 #endif // TARGET_OS_WATCH
 101
 102     // Check for all the special (negative) internal value interface indices before initializing client_ifindex
 103     if (   (q->InterfaceID == mDNSInterface_Any)
 104         || (q->InterfaceID == mDNSInterface_LocalOnly)
 105         || (q->InterfaceID == mDNSInterfaceMark)
 106         || (q->InterfaceID == mDNSInterface_P2P)
 107         || (q->InterfaceID == mDNSInterface_BLE)
 108         || (q->InterfaceID == uDNSInterfaceMark))
 109     {
 110         client_ifindex = 0;
 111     }
 112     else
 113     {
 114         client_ifindex = (mDNSu32)(uintptr_t)q->InterfaceID;
 115     }
 116
 117     if (client_ifindex > 0)
 118     {
 119         nw_interface_t client_intf = nw_interface_create_with_index(client_ifindex);
 120         if (client_intf)
 121         {
 122             nw_parameters_require_interface(parameters, client_intf);
 123             _nw_forget(&client_intf);
 124         }
 125         else
 126         {
 127             LogRedact(MDNS_LOG_CATEGORY_DEFAULT, MDNS_LOG_INFO,
 128                 "[Q%u] mDNSPlatformGetDNSRoutePolicy: nw_interface_create_with_index() returned NULL for index %u",
 129                 mDNSVal16(q->TargetQID), client_ifindex);
 130         }
 131     }
 132
 133     nw_parameters_set_uid(parameters,(uid_t)q->euid);
 134
 135     if (q->pid != 0)
 136     {
 137         nw_parameters_set_pid(parameters, q->pid);
 138         retval = proc_pidinfo(q->pid, PROC_PIDUNIQIDENTIFIERINFO, 1, &info, sizeof(info));
 139         if (retval == (int)sizeof(info))
 140         {
 141             nw_parameters_set_e_proc_uuid(parameters, info.p_uuid);
 142             isUUIDSet = mDNStrue;
 143         }
 144         else
 145         {
 146             debugf("mDNSPlatformGetDNSRoutePolicy: proc_pidinfo returned %d", retval);
 147             isUUIDSet = mDNSfalse;
 148         }
 149     }
 150     else
 151     {
 152         nw_parameters_set_e_proc_uuid(parameters, q->uuid);
 153         isUUIDSet = mDNStrue;
 154     }
 155
 156     evaluator = nw_path_create_evaluator_for_endpoint(host, parameters);
 157     if (evaluator == NULL)
 158     {
 159         LogRedact(MDNS_LOG_CATEGORY_DEFAULT, MDNS_LOG_ERROR,
 160             "[Q%u] mDNSPlatformGetDNSRoutePolicy: Query for " PRI_DM_NAME " (" PUB_S "), PID[%d], EUID[%d], ServiceID[%d]"
 161             " evaluator is NULL",
 162             mDNSVal16(q->TargetQID), DM_NAME_PARAM(&q->qname), DNSTypeName(q->qtype), q->pid, q->euid, q->ServiceID);
 163         goto exit;
 164     }
 165     _nw_forget(&host);
 166     _nw_forget(&parameters);
 167
 168     path = nw_path_evaluator_copy_path(evaluator);
 169     if (path == NULL)
 170     {
 171         LogRedact(MDNS_LOG_CATEGORY_DEFAULT, MDNS_LOG_ERROR,
 172             "[Q%u] mDNSPlatformGetDNSRoutePolicy: Query for " PRI_DM_NAME " (" PUB_S "), PID[%d], EUID[%d], ServiceID[%d]"
 173             " path is NULL",
 174             mDNSVal16(q->TargetQID), DM_NAME_PARAM(&q->qname), DNSTypeName(q->qtype), q->pid, q->euid, q->ServiceID);
 175         goto exit;
 176     }
 177     service_id = nw_path_get_flow_divert_unit(path);
 178     if (service_id != 0)
 179     {
 180         q->ServiceID = service_id;
 181         LogRedact(MDNS_LOG_CATEGORY_DEFAULT, MDNS_LOG_INFO,
 182             "[Q%u] mDNSPlatformGetDNSRoutePolicy: Query for " PRI_DM_NAME " service ID is set ->service_ID:[%d] ",
 183             mDNSVal16(q->TargetQID), DM_NAME_PARAM(&q->qname), service_id);
 184     }
 185     else
 186     {
 187         nw_interface_t nwpath_intf = nw_path_copy_scoped_interface(path);
 188         if (nwpath_intf != NULL)
 189         {
 190             // Use the new scoped interface given by NW PATH EVALUATOR
 191             dnspol_ifindex = nw_interface_get_index(nwpath_intf);
 192             q->InterfaceID = (mDNSInterfaceID)(uintptr_t)dnspol_ifindex;
 193
 194             _nw_forget(&nwpath_intf);
 195
 196             if (dnspol_ifindex != client_ifindex)
 197             {
 198                 LogRedact(MDNS_LOG_CATEGORY_DEFAULT, MDNS_LOG_INFO,
 199                     "[Q%u] mDNSPlatformGetDNSRoutePolicy: DNS Route Policy has changed the scoped ifindex from [%d] to [%d]",
 200                     mDNSVal16(q->TargetQID), client_ifindex, dnspol_ifindex);
 201             }
 202         }
 203         else
 204         {
 205             debugf("mDNSPlatformGetDNSRoutePolicy: Query for %##s (%s), PID[%d], EUID[%d], ServiceID[%d] nw_interface_t nwpath_intf is NULL ", q->qname.c, DNSTypeName(q->qtype), q->pid, q->euid, q->ServiceID);
 206         }
 207     }
 208
 209 #if MDNSRESPONDER_SUPPORTS(APPLE, QUERIER)
 210     uuid_clear(q->ResolverUUID);
 211     if (__builtin_available(macOS 10.16, iOS 14.0, watchOS 7.0, tvOS 14.0, *))
 212     {
 213         if (path != NULL)
 214         {
 215             __block nw_resolver_config_t best_config = NULL;
 216             __block nw_resolver_class_t best_class = nw_resolver_class_default_direct;
 217             nw_path_enumerate_resolver_configs(path,
 218             ^bool(nw_resolver_config_t config)
 219             {
 220                 const nw_resolver_class_t class = nw_resolver_config_get_class(config);
 221                 if (class != nw_resolver_class_default_direct &&
 222                     (best_class == nw_resolver_class_default_direct || class < best_class))
 223                 {
 224                     best_class = class;
 225                     best_config = config;
 226                 }
 227                 return true;
 228             });
 229             if (best_config != NULL)
 230             {
 231                 nw_resolver_config_get_identifier(best_config, q->ResolverUUID);
 232             }
 233         }
 234     }
 235     if (!uuid_is_null(q->ResolverUUID))
 236     {
 237         Querier_RegisterPathResolver(q->ResolverUUID);
 238     }
 239 #endif
 240     if (isUUIDSet && path && (nw_path_get_status(path) == nw_path_status_unsatisfied) && (nw_path_get_reason(path) != nw_path_reason_no_route))
 241     {
 242         isBlocked = mDNStrue;
 243     }
 244
 245 exit:
 246     _nw_forget(&host);
 247     _nw_forget(&parameters);
 248     _nw_forget(&path);
 249     _nw_forget(&evaluator);
 250     q->BlockedByPolicy = isBlocked;
 251 }