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 <log/log.h>
30 #include <qtaguid/qtaguid.h>
31
32 static const char* CTRL_PROCPATH = "/proc/net/xt_qtaguid/ctrl";
33 static const int CTRL_MAX_INPUT_LEN = 128;
34
35 /*
36 * One per proccess.
37 * Once the device is open, this process will have its socket tags tracked.
38 * And on exit or untimely death, all socket tags will be removed.
39 * A process can only open /dev/xt_qtaguid once.
40 * It should not close it unless it is really done with all the socket tags.
41 * Failure to open it will be visible when socket tagging will be attempted.
42 */
43 static int resTrackFd = -1;
44 pthread_once_t resTrackInitDone = PTHREAD_ONCE_INIT;
45
46 /* Only call once per process. */
legacy_resTrack(void)47 void legacy_resTrack(void) {
48 resTrackFd = TEMP_FAILURE_RETRY(open("/dev/xt_qtaguid", O_RDONLY | O_CLOEXEC));
49 }
50
51 /*
52 * Returns:
53 * 0 on success.
54 * -errno on failure.
55 */
write_ctrl(const char * cmd)56 static int write_ctrl(const char* cmd) {
57 int fd, res, savedErrno;
58
59 ALOGV("write_ctrl(%s)", cmd);
60
61 fd = TEMP_FAILURE_RETRY(open(CTRL_PROCPATH, O_WRONLY | O_CLOEXEC));
62 if (fd < 0) {
63 return -errno;
64 }
65
66 res = TEMP_FAILURE_RETRY(write(fd, cmd, strlen(cmd)));
67 if (res < 0) {
68 savedErrno = errno;
69 } else {
70 savedErrno = 0;
71 }
72 if (res < 0) {
73 // ALOGV is enough because all the callers also log failures
74 ALOGV("Failed write_ctrl(%s) res=%d errno=%d", cmd, res, savedErrno);
75 }
76 close(fd);
77 return -savedErrno;
78 }
79
legacy_tagSocket(int sockfd,int tag,uid_t uid)80 int legacy_tagSocket(int sockfd, int tag, uid_t uid) {
81 char lineBuf[CTRL_MAX_INPUT_LEN];
82 int res;
83 uint64_t kTag = ((uint64_t)tag << 32);
84
85 pthread_once(&resTrackInitDone, legacy_resTrack);
86
87 snprintf(lineBuf, sizeof(lineBuf), "t %d %" PRIu64 " %d", sockfd, kTag, uid);
88
89 ALOGV("Tagging socket %d with tag %" PRIx64 "{%u,0} for uid %d", sockfd, kTag, tag, uid);
90
91 res = write_ctrl(lineBuf);
92 if (res < 0) {
93 ALOGI("Tagging socket %d with tag %" PRIx64 "(%d) for uid %d failed errno=%d", sockfd, kTag,
94 tag, uid, res);
95 }
96
97 return res;
98 }
99
legacy_untagSocket(int sockfd)100 int legacy_untagSocket(int sockfd) {
101 char lineBuf[CTRL_MAX_INPUT_LEN];
102 int res;
103
104 ALOGV("Untagging socket %d", sockfd);
105
106 snprintf(lineBuf, sizeof(lineBuf), "u %d", sockfd);
107 res = write_ctrl(lineBuf);
108 if (res < 0) {
109 ALOGI("Untagging socket %d failed errno=%d", sockfd, res);
110 }
111
112 return res;
113 }
114
legacy_setCounterSet(int counterSetNum,uid_t uid)115 int legacy_setCounterSet(int counterSetNum, uid_t uid) {
116 char lineBuf[CTRL_MAX_INPUT_LEN];
117 int res;
118
119 ALOGV("Setting counters to set %d for uid %d", counterSetNum, uid);
120
121 snprintf(lineBuf, sizeof(lineBuf), "s %d %d", counterSetNum, uid);
122 res = write_ctrl(lineBuf);
123 return res;
124 }
125
legacy_deleteTagData(int tag,uid_t uid)126 int legacy_deleteTagData(int tag, uid_t uid) {
127 char lineBuf[CTRL_MAX_INPUT_LEN];
128 int cnt = 0, res = 0;
129 uint64_t kTag = (uint64_t)tag << 32;
130
131 ALOGV("Deleting tag data with tag %" PRIx64 "{%d,0} for uid %d", kTag, tag, uid);
132
133 pthread_once(&resTrackInitDone, legacy_resTrack);
134
135 snprintf(lineBuf, sizeof(lineBuf), "d %" PRIu64 " %d", kTag, uid);
136 res = write_ctrl(lineBuf);
137 if (res < 0) {
138 ALOGI("Deleting tag data with tag %" PRIx64 "/%d for uid %d failed with cnt=%d errno=%d",
139 kTag, tag, uid, cnt, errno);
140 }
141
142 return res;
143 }
144