// Copyright (C) 2016 The Android Open Source Project
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include <sys/capability.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <libminijail.h>
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#include <android-base/logging.h>
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#include <android-base/macros.h>
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const uid_t kSystemUid = 1000U;
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gid_t groups[] = {kSystemUid + 1, kSystemUid + 2};
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size_t getgroups_with_alloc(gid_t** plist) {
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*plist = NULL;
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int nsupp_groups = getgroups(0, NULL);
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if (nsupp_groups < 0) {
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PLOG(ERROR) << "getgroups(0)";
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return 0;
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}
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if (nsupp_groups == 0) {
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LOG(INFO) << "No supplementary groups.";
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return 0;
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}
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*plist = (gid_t*)calloc((size_t)nsupp_groups, sizeof(gid_t));
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nsupp_groups = getgroups(nsupp_groups, *plist);
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if (nsupp_groups < 0) {
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PLOG(ERROR) << "getgroups(nsupp_groups)";
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free(*plist);
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return 0;
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}
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return nsupp_groups;
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}
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bool check_ugid(uid_t expected_id) {
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bool success = true;
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uid_t ruid = getuid();
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if (ruid != expected_id) {
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LOG(ERROR) << "rUID " << ruid << " is not " << expected_id;
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success = false;
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}
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gid_t rgid = getgid();
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if (rgid != expected_id) {
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LOG(ERROR) << "rGID " << ruid << " is not " << expected_id;
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success = false;
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}
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return success;
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}
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bool check_groups(size_t expected_size, gid_t* expected_list) {
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bool success = true;
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gid_t* actual_list;
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size_t actual_size = getgroups_with_alloc(&actual_list);
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if (expected_size != actual_size) {
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LOG(ERROR) << "Mismatched supplementary group list size: expected "
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<< expected_size << ", actual " << actual_size;
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success = false;
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}
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for (size_t i = 0; i < expected_size; i++) {
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bool found = false;
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for (size_t j = 0; j < actual_size; j++) {
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if (expected_list[i] == actual_list[j]) {
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// Test next expected GID.
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found = true;
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break;
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}
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}
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if (!found) {
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LOG(ERROR) << "Expected GID " << expected_list[i] << " not found.";
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success = false;
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}
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}
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free(actual_list);
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return success;
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}
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void log_resugid() {
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uid_t ruid, euid, suid;
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gid_t rgid, egid, sgid;
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getresuid(&ruid, &euid, &suid);
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getresgid(&rgid, &egid, &sgid);
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LOG(INFO) << "ruid " << ruid << " euid " << euid << " suid " << suid;
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LOG(INFO) << "rgid " << rgid << " egid " << egid << " sgid " << sgid;
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gid_t* list;
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size_t nsupp_groups = getgroups_with_alloc(&list);
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for (size_t i = 0; i < (size_t)nsupp_groups; i++) {
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LOG(INFO) << "supp gid " << i + 1 << " " << list[i];
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}
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free(list);
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}
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int main(void) {
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minijail* j = minijail_new();
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minijail_change_user(j, "system");
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minijail_change_group(j, "system");
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size_t num_groups = arraysize(groups);
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minijail_set_supplementary_gids(j, num_groups, groups);
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minijail_use_caps(j, CAP_TO_MASK(CAP_SETUID) | CAP_TO_MASK(CAP_SETGID));
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minijail_enter(j);
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bool success = check_ugid(kSystemUid);
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success = success && check_groups(num_groups, groups);
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minijail_destroy(j);
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minijail* j2 = minijail_new();
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minijail_change_uid(j2, 5 * kSystemUid);
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minijail_change_gid(j2, 5 * kSystemUid);
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minijail_enter(j2);
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success = success && check_ugid(5 * kSystemUid);
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return success ? 0 : 1;
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}
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