1 // Copyright (C) 2016 The Android Open Source Project
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 #include <sys/types.h>
16 #include <sys/capability.h>
17 #include <unistd.h>
18
19 #include <libminijail.h>
20
21 #include <android-base/logging.h>
22
23 const uid_t kSystemUid = 1000U;
24
25 gid_t groups[] = { kSystemUid + 1, kSystemUid + 2 };
26
getgroups_with_alloc(gid_t ** plist)27 size_t getgroups_with_alloc(gid_t **plist) {
28 *plist = NULL;
29
30 int nsupp_groups = getgroups(0, NULL);
31 if (nsupp_groups < 0) {
32 PLOG(ERROR) << "getgroups(0)";
33 return 0;
34 }
35 if (nsupp_groups == 0) {
36 LOG(INFO) << "No supplementary groups.";
37 return 0;
38 }
39
40 *plist = (gid_t*)calloc((size_t)nsupp_groups, sizeof(gid_t));
41 nsupp_groups = getgroups(nsupp_groups, *plist);
42 if (nsupp_groups < 0) {
43 PLOG(ERROR) << "getgroups(nsupp_groups)";
44 free(*plist);
45 return 0;
46 }
47 return nsupp_groups;
48 }
49
check_ugid(uid_t expected_id)50 bool check_ugid(uid_t expected_id) {
51 bool success = true;
52
53 uid_t ruid = getuid();
54 if (ruid != expected_id) {
55 LOG(ERROR) << "rUID " << ruid << " is not " << expected_id;
56 success = false;
57 }
58 gid_t rgid = getgid();
59 if (rgid != expected_id) {
60 LOG(ERROR) << "rGID " << ruid << " is not " << expected_id;
61 success = false;
62 }
63 return success;
64 }
65
check_groups(size_t expected_size,gid_t * expected_list)66 bool check_groups(size_t expected_size, gid_t *expected_list) {
67 bool success = true;
68
69 gid_t *actual_list;
70 size_t actual_size = getgroups_with_alloc(&actual_list);
71
72 if (expected_size != actual_size) {
73 LOG(ERROR) << "Mismatched supplementary group list size: expected "
74 << expected_size << ", actual " << actual_size;
75 success = false;
76 }
77
78 for (size_t i = 0; i < expected_size; i++) {
79 bool found = false;
80 for (size_t j = 0; j < actual_size; j++) {
81 if (expected_list[i] == actual_list[j]) {
82 // Test next expected GID.
83 found = true;
84 break;
85 }
86 }
87 if (!found) {
88 LOG(ERROR) << "Expected GID " << expected_list[i] << " not found.";
89 success = false;
90 }
91 }
92 free(actual_list);
93 return success;
94 }
95
log_resugid()96 void log_resugid() {
97 uid_t ruid, euid, suid;
98 gid_t rgid, egid, sgid;
99 getresuid(&ruid, &euid, &suid);
100 getresgid(&rgid, &egid, &sgid);
101
102 LOG(INFO) << "ruid " << ruid << " euid " << euid << " suid " << suid;
103 LOG(INFO) << "rgid " << rgid << " egid " << egid << " sgid " << sgid;
104
105 gid_t *list;
106 size_t nsupp_groups = getgroups_with_alloc(&list);
107 for (size_t i = 0; i < (size_t)nsupp_groups; i++) {
108 LOG(INFO) << "supp gid " << i + 1 << " " << list[i];
109 }
110 free(list);
111 }
112
main(void)113 int main(void) {
114 minijail *j = minijail_new();
115 minijail_change_user(j, "system");
116 minijail_change_group(j, "system");
117 size_t num_groups = sizeof(groups) / sizeof(groups[0]);
118 minijail_set_supplementary_gids(j, num_groups, groups);
119 minijail_use_caps(j, CAP_TO_MASK(CAP_SETUID) | CAP_TO_MASK(CAP_SETGID));
120 minijail_enter(j);
121
122 bool success = check_ugid(kSystemUid);
123 success = success && check_groups(num_groups, groups);
124
125 minijail_destroy(j);
126 minijail *j2 = minijail_new();
127 minijail_change_uid(j2, 5 * kSystemUid);
128 minijail_change_gid(j2, 5 * kSystemUid);
129 minijail_enter(j2);
130
131 success = success && check_ugid(5 * kSystemUid);
132
133 return success? 0 : 1;
134 }
135