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      1 /*
      2  * Copyright (C) 2018 The Android Open Source Project
      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  *      http://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 "socket_peer_is_trusted.h"
     18 
     19 #if !defined(_WIN32)
     20 #include <pwd.h>
     21 #include <sys/socket.h>
     22 #endif
     23 
     24 #include <android-base/logging.h>
     25 
     26 namespace art {
     27 
     28 // Returns true if the user on the other end of the socket is root or shell.
     29 #ifdef ART_TARGET_ANDROID
     30 bool SocketPeerIsTrusted(int fd) {
     31   ucred cr;
     32   socklen_t cr_length = sizeof(cr);
     33   if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &cr, &cr_length) != 0) {
     34     PLOG(ERROR) << "couldn't get socket credentials";
     35     return false;
     36   }
     37 
     38   passwd* shell = getpwnam("shell");
     39   if (cr.uid != 0 && cr.uid != shell->pw_uid) {
     40     LOG(ERROR) << "untrusted uid " << cr.uid << " on other end of socket";
     41     return false;
     42   }
     43 
     44   return true;
     45 }
     46 #else
     47 bool SocketPeerIsTrusted(int /* fd */) {
     48   return true;
     49 }
     50 #endif
     51 
     52 }  // namespace art
     53