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/capability.h>
16 #include <sys/types.h>
17 #include <unistd.h>
18
19 #include <libminijail.h>
20
21 #include <android-base/logging.h>
22 #include <android-base/macros.h>
23
24 const uid_t kSystemUid = 1000U;
25
26 gid_t groups[] = {kSystemUid + 1, kSystemUid + 2};
27
getgroups_with_alloc(gid_t ** plist)28 size_t getgroups_with_alloc(gid_t** plist) {
29 *plist = NULL;
30
31 int nsupp_groups = getgroups(0, NULL);
32 if (nsupp_groups < 0) {
33 PLOG(ERROR) << "getgroups(0)";
34 return 0;
35 }
36 if (nsupp_groups == 0) {
37 LOG(INFO) << "No supplementary groups.";
38 return 0;
39 }
40
41 *plist = (gid_t*)calloc((size_t)nsupp_groups, sizeof(gid_t));
42 nsupp_groups = getgroups(nsupp_groups, *plist);
43 if (nsupp_groups < 0) {
44 PLOG(ERROR) << "getgroups(nsupp_groups)";
45 free(*plist);
46 return 0;
47 }
48 return nsupp_groups;
49 }
50
check_ugid(uid_t expected_id)51 bool check_ugid(uid_t expected_id) {
52 bool success = true;
53
54 uid_t ruid = getuid();
55 if (ruid != expected_id) {
56 LOG(ERROR) << "rUID " << ruid << " is not " << expected_id;
57 success = false;
58 }
59 gid_t rgid = getgid();
60 if (rgid != expected_id) {
61 LOG(ERROR) << "rGID " << ruid << " is not " << expected_id;
62 success = false;
63 }
64 return success;
65 }
66
check_groups(size_t expected_size,gid_t * expected_list)67 bool check_groups(size_t expected_size, gid_t* expected_list) {
68 bool success = true;
69
70 gid_t* actual_list;
71 size_t actual_size = getgroups_with_alloc(&actual_list);
72
73 if (expected_size != actual_size) {
74 LOG(ERROR) << "Mismatched supplementary group list size: expected "
75 << expected_size << ", actual " << actual_size;
76 success = false;
77 }
78
79 for (size_t i = 0; i < expected_size; i++) {
80 bool found = false;
81 for (size_t j = 0; j < actual_size; j++) {
82 if (expected_list[i] == actual_list[j]) {
83 // Test next expected GID.
84 found = true;
85 break;
86 }
87 }
88 if (!found) {
89 LOG(ERROR) << "Expected GID " << expected_list[i] << " not found.";
90 success = false;
91 }
92 }
93 free(actual_list);
94 return success;
95 }
96
log_resugid()97 void log_resugid() {
98 uid_t ruid, euid, suid;
99 gid_t rgid, egid, sgid;
100 getresuid(&ruid, &euid, &suid);
101 getresgid(&rgid, &egid, &sgid);
102
103 LOG(INFO) << "ruid " << ruid << " euid " << euid << " suid " << suid;
104 LOG(INFO) << "rgid " << rgid << " egid " << egid << " sgid " << sgid;
105
106 gid_t* list;
107 size_t nsupp_groups = getgroups_with_alloc(&list);
108 for (size_t i = 0; i < (size_t)nsupp_groups; i++) {
109 LOG(INFO) << "supp gid " << i + 1 << " " << list[i];
110 }
111 free(list);
112 }
113
main(void)114 int main(void) {
115 minijail* j = minijail_new();
116 minijail_change_user(j, "system");
117 minijail_change_group(j, "system");
118 size_t num_groups = arraysize(groups);
119 minijail_set_supplementary_gids(j, num_groups, groups);
120 minijail_use_caps(j, CAP_TO_MASK(CAP_SETUID) | CAP_TO_MASK(CAP_SETGID));
121 minijail_enter(j);
122
123 bool success = check_ugid(kSystemUid);
124 success = success && check_groups(num_groups, groups);
125
126 minijail_destroy(j);
127 minijail* j2 = minijail_new();
128 minijail_change_uid(j2, 5 * kSystemUid);
129 minijail_change_gid(j2, 5 * kSystemUid);
130 minijail_enter(j2);
131
132 success = success && check_ugid(5 * kSystemUid);
133
134 return success ? 0 : 1;
135 }
136