1/* libcutils/qtaguid.c
2**
3** Copyright 2011, The Android Open Source Project
4**
5** Licensed under the Apache License, Version 2.0 (the "License");
6** you may not use this file except in compliance with the License.
7** You may obtain a copy of the License at
8**
9**     http://www.apache.org/licenses/LICENSE-2.0
10**
11** Unless required by applicable law or agreed to in writing, software
12** distributed under the License is distributed on an "AS IS" BASIS,
13** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14** See the License for the specific language governing permissions and
15** limitations under the License.
16*/
17
18// #define LOG_NDEBUG 0
19
20#define LOG_TAG "qtaguid"
21
22#include <cutils/qtaguid.h>
23#include <cutils/log.h>
24#include <errno.h>
25#include <fcntl.h>
26#include <stdio.h>
27#include <string.h>
28#include <unistd.h>
29#include <pthread.h>
30
31static const char* CTRL_PROCPATH = "/proc/net/xt_qtaguid/ctrl";
32static const int CTRL_MAX_INPUT_LEN = 128;
33static const char *GLOBAL_PACIFIER_PARAM = "/sys/module/xt_qtaguid/parameters/passive";
34static const char *TAG_PACIFIER_PARAM = "/sys/module/xt_qtaguid/parameters/tag_tracking_passive";
35
36/*
37 * One per proccess.
38 * Once the device is open, this process will have its socket tags tracked.
39 * And on exit or untimely death, all socket tags will be removed.
40 * A process can only open /dev/xt_qtaguid once.
41 * It should not close it unless it is really done with all the socket tags.
42 * Failure to open it will be visible when socket tagging will be attempted.
43 */
44static int resTrackFd = -1;
45pthread_once_t resTrackInitDone = PTHREAD_ONCE_INIT;
46
47/* Only call once per process. */
48void qtaguid_resTrack(void) {
49    resTrackFd = TEMP_FAILURE_RETRY(open("/dev/xt_qtaguid", O_RDONLY));
50    if (resTrackFd >=0) {
51        TEMP_FAILURE_RETRY(fcntl(resTrackFd, F_SETFD, FD_CLOEXEC));
52    }
53}
54
55/*
56 * Returns:
57 *   0 on success.
58 *   -errno on failure.
59 */
60static int write_ctrl(const char *cmd) {
61    int fd, res, savedErrno;
62
63    ALOGV("write_ctrl(%s)", cmd);
64
65    fd = TEMP_FAILURE_RETRY(open(CTRL_PROCPATH, O_WRONLY));
66    if (fd < 0) {
67        return -errno;
68    }
69
70    res = TEMP_FAILURE_RETRY(write(fd, cmd, strlen(cmd)));
71    if (res < 0) {
72        savedErrno = errno;
73    } else {
74        savedErrno = 0;
75    }
76    if (res < 0) {
77        ALOGI("Failed write_ctrl(%s) res=%d errno=%d", cmd, res, savedErrno);
78    }
79    close(fd);
80    return -savedErrno;
81}
82
83static int write_param(const char *param_path, const char *value) {
84    int param_fd;
85    int res;
86
87    param_fd = TEMP_FAILURE_RETRY(open(param_path, O_WRONLY));
88    if (param_fd < 0) {
89        return -errno;
90    }
91    res = TEMP_FAILURE_RETRY(write(param_fd, value, strlen(value)));
92    if (res < 0) {
93        return -errno;
94    }
95    close(param_fd);
96    return 0;
97}
98
99int qtaguid_tagSocket(int sockfd, int tag, uid_t uid) {
100    char lineBuf[CTRL_MAX_INPUT_LEN];
101    int res;
102    uint64_t kTag = ((uint64_t)tag << 32);
103
104    pthread_once(&resTrackInitDone, qtaguid_resTrack);
105
106    snprintf(lineBuf, sizeof(lineBuf), "t %d %llu %d", sockfd, kTag, uid);
107
108    ALOGV("Tagging socket %d with tag %llx{%u,0} for uid %d", sockfd, kTag, tag, uid);
109
110    res = write_ctrl(lineBuf);
111    if (res < 0) {
112        ALOGI("Tagging socket %d with tag %llx(%d) for uid %d failed errno=%d",
113             sockfd, kTag, tag, uid, res);
114    }
115
116    return res;
117}
118
119int qtaguid_untagSocket(int sockfd) {
120    char lineBuf[CTRL_MAX_INPUT_LEN];
121    int res;
122
123    ALOGV("Untagging socket %d", sockfd);
124
125    snprintf(lineBuf, sizeof(lineBuf), "u %d", sockfd);
126    res = write_ctrl(lineBuf);
127    if (res < 0) {
128        ALOGI("Untagging socket %d failed errno=%d", sockfd, res);
129    }
130
131    return res;
132}
133
134int qtaguid_setCounterSet(int counterSetNum, uid_t uid) {
135    char lineBuf[CTRL_MAX_INPUT_LEN];
136    int res;
137
138    ALOGV("Setting counters to set %d for uid %d", counterSetNum, uid);
139
140    snprintf(lineBuf, sizeof(lineBuf), "s %d %d", counterSetNum, uid);
141    res = write_ctrl(lineBuf);
142    return res;
143}
144
145int qtaguid_deleteTagData(int tag, uid_t uid) {
146    char lineBuf[CTRL_MAX_INPUT_LEN];
147    int fd, cnt = 0, res = 0;
148    uint64_t kTag = (uint64_t)tag << 32;
149
150    ALOGV("Deleting tag data with tag %llx{%d,0} for uid %d", kTag, tag, uid);
151
152    pthread_once(&resTrackInitDone, qtaguid_resTrack);
153
154    snprintf(lineBuf, sizeof(lineBuf), "d %llu %d", kTag, uid);
155    res = write_ctrl(lineBuf);
156    if (res < 0) {
157        ALOGI("Deleteing tag data with tag %llx/%d for uid %d failed with cnt=%d errno=%d",
158             kTag, tag, uid, cnt, errno);
159    }
160
161    return res;
162}
163
164int qtaguid_setPacifier(int on) {
165    int param_fd;
166    int res;
167    const char *value;
168
169    value = on ? "Y" : "N";
170    if (write_param(GLOBAL_PACIFIER_PARAM, value) < 0) {
171        return -errno;
172    }
173    if (write_param(TAG_PACIFIER_PARAM, value) < 0) {
174        return -errno;
175    }
176    return 0;
177}
178