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      1 /*
      2  * Copyright 2017, 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 <cutils/qtaguid.h>
     18 
     19 // #define LOG_NDEBUG 0
     20 
     21 #define LOG_TAG "qtaguid"
     22 
     23 #include <dlfcn.h>
     24 #include <errno.h>
     25 #include <fcntl.h>
     26 #include <inttypes.h>
     27 #include <stdio.h>
     28 #include <string.h>
     29 #include <unistd.h>
     30 
     31 #include <log/log.h>
     32 
     33 class netdHandler {
     34   public:
     35     int (*netdTagSocket)(int, uint32_t, uid_t);
     36     int (*netdUntagSocket)(int);
     37     int (*netdSetCounterSet)(uint32_t, uid_t);
     38     int (*netdDeleteTagData)(uint32_t, uid_t);
     39 };
     40 
     41 int dummyTagSocket(int, uint32_t, uid_t) {
     42     return -EREMOTEIO;
     43 }
     44 
     45 int dummyUntagSocket(int) {
     46     return -EREMOTEIO;
     47 }
     48 
     49 int dummySetCounterSet(uint32_t, uid_t) {
     50     return -EREMOTEIO;
     51 }
     52 
     53 int dummyDeleteTagData(uint32_t, uid_t) {
     54     return -EREMOTEIO;
     55 }
     56 
     57 netdHandler initHandler(void) {
     58     netdHandler handler = {dummyTagSocket, dummyUntagSocket, dummySetCounterSet, dummyDeleteTagData};
     59 
     60     void* netdClientHandle = dlopen("libnetd_client.so", RTLD_NOW);
     61     if (!netdClientHandle) {
     62         ALOGE("Failed to open libnetd_client.so: %s", dlerror());
     63         return handler;
     64     }
     65 
     66     handler.netdTagSocket = (int (*)(int, uint32_t, uid_t))dlsym(netdClientHandle, "tagSocket");
     67     if (!handler.netdTagSocket) {
     68         ALOGE("load netdTagSocket handler failed: %s", dlerror());
     69     }
     70 
     71     handler.netdUntagSocket = (int (*)(int))dlsym(netdClientHandle, "untagSocket");
     72     if (!handler.netdUntagSocket) {
     73         ALOGE("load netdUntagSocket handler failed: %s", dlerror());
     74     }
     75 
     76     handler.netdSetCounterSet = (int (*)(uint32_t, uid_t))dlsym(netdClientHandle, "setCounterSet");
     77     if (!handler.netdSetCounterSet) {
     78         ALOGE("load netdSetCounterSet handler failed: %s", dlerror());
     79     }
     80 
     81     handler.netdDeleteTagData = (int (*)(uint32_t, uid_t))dlsym(netdClientHandle, "deleteTagData");
     82     if (!handler.netdDeleteTagData) {
     83         ALOGE("load netdDeleteTagData handler failed: %s", dlerror());
     84     }
     85     return handler;
     86 }
     87 
     88 // The language guarantees that this object will be initialized in a thread-safe way.
     89 static netdHandler& getHandler() {
     90     static netdHandler instance = initHandler();
     91     return instance;
     92 }
     93 
     94 int qtaguid_tagSocket(int sockfd, int tag, uid_t uid) {
     95     // Check the socket fd passed to us is still valid before we load the netd
     96     // client. Pass a already closed socket fd to netd client may let netd open
     97     // the unix socket with the same fd number and pass it to server for
     98     // tagging.
     99     // TODO: move the check into netdTagSocket.
    100     int res = fcntl(sockfd, F_GETFD);
    101     if (res < 0) return res;
    102 
    103     ALOGV("Tagging socket %d with tag %u for uid %d", sockfd, tag, uid);
    104     return getHandler().netdTagSocket(sockfd, tag, uid);
    105 }
    106 
    107 int qtaguid_untagSocket(int sockfd) {
    108     // Similiar to tag socket. We need a check before untag to make sure untag a closed socket fail
    109     // as expected.
    110     // TODO: move the check into netdTagSocket.
    111     int res = fcntl(sockfd, F_GETFD);
    112     if (res < 0) return res;
    113 
    114     ALOGV("Untagging socket %d", sockfd);
    115     return getHandler().netdUntagSocket(sockfd);
    116 }
    117 
    118 int qtaguid_setCounterSet(int counterSetNum, uid_t uid) {
    119     ALOGV("Setting counters to set %d for uid %d", counterSetNum, uid);
    120     return getHandler().netdSetCounterSet(counterSetNum, uid);
    121 }
    122 
    123 int qtaguid_deleteTagData(int tag, uid_t uid) {
    124     ALOGV("Deleting tag data with tag %u for uid %d", tag, uid);
    125     return getHandler().netdDeleteTagData(tag, uid);
    126 }
    127