1 /*
2 ** Copyright 2011, 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 // #define LOG_NDEBUG 0
18
19 #define LOG_TAG "qtaguid"
20
21 #include <errno.h>
22 #include <fcntl.h>
23 #include <inttypes.h>
24 #include <pthread.h>
25 #include <stdio.h>
26 #include <string.h>
27 #include <unistd.h>
28
29 #include <cutils/qtaguid.h>
30 #include <log/log.h>
31
32 static const char* CTRL_PROCPATH = "/proc/net/xt_qtaguid/ctrl";
33 static const int CTRL_MAX_INPUT_LEN = 128;
34 static const char *GLOBAL_PACIFIER_PARAM = "/sys/module/xt_qtaguid/parameters/passive";
35 static const char *TAG_PACIFIER_PARAM = "/sys/module/xt_qtaguid/parameters/tag_tracking_passive";
36
37 /*
38 * One per proccess.
39 * Once the device is open, this process will have its socket tags tracked.
40 * And on exit or untimely death, all socket tags will be removed.
41 * A process can only open /dev/xt_qtaguid once.
42 * It should not close it unless it is really done with all the socket tags.
43 * Failure to open it will be visible when socket tagging will be attempted.
44 */
45 static int resTrackFd = -1;
46 pthread_once_t resTrackInitDone = PTHREAD_ONCE_INIT;
47
48 /* Only call once per process. */
qtaguid_resTrack(void)49 void qtaguid_resTrack(void) {
50 resTrackFd = TEMP_FAILURE_RETRY(open("/dev/xt_qtaguid", O_RDONLY));
51 if (resTrackFd >=0) {
52 TEMP_FAILURE_RETRY(fcntl(resTrackFd, F_SETFD, FD_CLOEXEC));
53 }
54 }
55
56 /*
57 * Returns:
58 * 0 on success.
59 * -errno on failure.
60 */
write_ctrl(const char * cmd)61 static int write_ctrl(const char *cmd) {
62 int fd, res, savedErrno;
63
64 ALOGV("write_ctrl(%s)", cmd);
65
66 fd = TEMP_FAILURE_RETRY(open(CTRL_PROCPATH, O_WRONLY));
67 if (fd < 0) {
68 return -errno;
69 }
70
71 res = TEMP_FAILURE_RETRY(write(fd, cmd, strlen(cmd)));
72 if (res < 0) {
73 savedErrno = errno;
74 } else {
75 savedErrno = 0;
76 }
77 if (res < 0) {
78 // ALOGV is enough because all the callers also log failures
79 ALOGV("Failed write_ctrl(%s) res=%d errno=%d", cmd, res, savedErrno);
80 }
81 close(fd);
82 return -savedErrno;
83 }
84
write_param(const char * param_path,const char * value)85 static int write_param(const char *param_path, const char *value) {
86 int param_fd;
87 int res;
88
89 param_fd = TEMP_FAILURE_RETRY(open(param_path, O_WRONLY));
90 if (param_fd < 0) {
91 return -errno;
92 }
93 res = TEMP_FAILURE_RETRY(write(param_fd, value, strlen(value)));
94 if (res < 0) {
95 return -errno;
96 }
97 close(param_fd);
98 return 0;
99 }
100
qtaguid_tagSocket(int sockfd,int tag,uid_t uid)101 int qtaguid_tagSocket(int sockfd, int tag, uid_t uid) {
102 char lineBuf[CTRL_MAX_INPUT_LEN];
103 int res;
104 uint64_t kTag = ((uint64_t)tag << 32);
105
106 pthread_once(&resTrackInitDone, qtaguid_resTrack);
107
108 snprintf(lineBuf, sizeof(lineBuf), "t %d %" PRIu64 " %d", sockfd, kTag, uid);
109
110 ALOGV("Tagging socket %d with tag %" PRIx64 "{%u,0} for uid %d", sockfd, kTag, tag, uid);
111
112 res = write_ctrl(lineBuf);
113 if (res < 0) {
114 ALOGI("Tagging socket %d with tag %" PRIx64 "(%d) for uid %d failed errno=%d",
115 sockfd, kTag, tag, uid, res);
116 }
117
118 return res;
119 }
120
qtaguid_untagSocket(int sockfd)121 int qtaguid_untagSocket(int sockfd) {
122 char lineBuf[CTRL_MAX_INPUT_LEN];
123 int res;
124
125 ALOGV("Untagging socket %d", sockfd);
126
127 snprintf(lineBuf, sizeof(lineBuf), "u %d", sockfd);
128 res = write_ctrl(lineBuf);
129 if (res < 0) {
130 ALOGI("Untagging socket %d failed errno=%d", sockfd, res);
131 }
132
133 return res;
134 }
135
qtaguid_setCounterSet(int counterSetNum,uid_t uid)136 int qtaguid_setCounterSet(int counterSetNum, uid_t uid) {
137 char lineBuf[CTRL_MAX_INPUT_LEN];
138 int res;
139
140 ALOGV("Setting counters to set %d for uid %d", counterSetNum, uid);
141
142 snprintf(lineBuf, sizeof(lineBuf), "s %d %d", counterSetNum, uid);
143 res = write_ctrl(lineBuf);
144 return res;
145 }
146
qtaguid_deleteTagData(int tag,uid_t uid)147 int qtaguid_deleteTagData(int tag, uid_t uid) {
148 char lineBuf[CTRL_MAX_INPUT_LEN];
149 int cnt = 0, res = 0;
150 uint64_t kTag = (uint64_t)tag << 32;
151
152 ALOGV("Deleting tag data with tag %" PRIx64 "{%d,0} for uid %d", kTag, tag, uid);
153
154 pthread_once(&resTrackInitDone, qtaguid_resTrack);
155
156 snprintf(lineBuf, sizeof(lineBuf), "d %" PRIu64 " %d", kTag, uid);
157 res = write_ctrl(lineBuf);
158 if (res < 0) {
159 ALOGI("Deleting tag data with tag %" PRIx64 "/%d for uid %d failed with cnt=%d errno=%d",
160 kTag, tag, uid, cnt, errno);
161 }
162
163 return res;
164 }
165
qtaguid_setPacifier(int on)166 int qtaguid_setPacifier(int on) {
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