276 lines · c
1// SPDX-License-Identifier: GPL-2.02 3#include <linux/limits.h>4#include <signal.h>5 6#include "../kselftest.h"7#include "cgroup_util.h"8 9static int idle_process_fn(const char *cgroup, void *arg)10{11 (void)pause();12 return 0;13}14 15static int do_migration_fn(const char *cgroup, void *arg)16{17 int object_pid = (int)(size_t)arg;18 19 if (setuid(TEST_UID))20 return EXIT_FAILURE;21 22 // XXX checking /proc/$pid/cgroup would be quicker than wait23 if (cg_enter(cgroup, object_pid) ||24 cg_wait_for_proc_count(cgroup, 1))25 return EXIT_FAILURE;26 27 return EXIT_SUCCESS;28}29 30static int do_controller_fn(const char *cgroup, void *arg)31{32 const char *child = cgroup;33 const char *parent = arg;34 35 if (setuid(TEST_UID))36 return EXIT_FAILURE;37 38 if (!cg_read_strstr(child, "cgroup.controllers", "cpuset"))39 return EXIT_FAILURE;40 41 if (cg_write(parent, "cgroup.subtree_control", "+cpuset"))42 return EXIT_FAILURE;43 44 if (cg_read_strstr(child, "cgroup.controllers", "cpuset"))45 return EXIT_FAILURE;46 47 if (cg_write(parent, "cgroup.subtree_control", "-cpuset"))48 return EXIT_FAILURE;49 50 if (!cg_read_strstr(child, "cgroup.controllers", "cpuset"))51 return EXIT_FAILURE;52 53 return EXIT_SUCCESS;54}55 56/*57 * Migrate a process between two sibling cgroups.58 * The success should only depend on the parent cgroup permissions and not the59 * migrated process itself (cpuset controller is in place because it uses60 * security_task_setscheduler() in cgroup v1).61 *62 * Deliberately don't set cpuset.cpus in children to avoid definining migration63 * permissions between two different cpusets.64 */65static int test_cpuset_perms_object(const char *root, bool allow)66{67 char *parent = NULL, *child_src = NULL, *child_dst = NULL;68 char *parent_procs = NULL, *child_src_procs = NULL, *child_dst_procs = NULL;69 const uid_t test_euid = TEST_UID;70 int object_pid = 0;71 int ret = KSFT_FAIL;72 73 parent = cg_name(root, "cpuset_test_0");74 if (!parent)75 goto cleanup;76 parent_procs = cg_name(parent, "cgroup.procs");77 if (!parent_procs)78 goto cleanup;79 if (cg_create(parent))80 goto cleanup;81 82 child_src = cg_name(parent, "cpuset_test_1");83 if (!child_src)84 goto cleanup;85 child_src_procs = cg_name(child_src, "cgroup.procs");86 if (!child_src_procs)87 goto cleanup;88 if (cg_create(child_src))89 goto cleanup;90 91 child_dst = cg_name(parent, "cpuset_test_2");92 if (!child_dst)93 goto cleanup;94 child_dst_procs = cg_name(child_dst, "cgroup.procs");95 if (!child_dst_procs)96 goto cleanup;97 if (cg_create(child_dst))98 goto cleanup;99 100 if (cg_write(parent, "cgroup.subtree_control", "+cpuset"))101 goto cleanup;102 103 if (cg_read_strstr(child_src, "cgroup.controllers", "cpuset") ||104 cg_read_strstr(child_dst, "cgroup.controllers", "cpuset"))105 goto cleanup;106 107 /* Enable permissions along src->dst tree path */108 if (chown(child_src_procs, test_euid, -1) ||109 chown(child_dst_procs, test_euid, -1))110 goto cleanup;111 112 if (allow && chown(parent_procs, test_euid, -1))113 goto cleanup;114 115 /* Fork a privileged child as a test object */116 object_pid = cg_run_nowait(child_src, idle_process_fn, NULL);117 if (object_pid < 0)118 goto cleanup;119 120 /* Carry out migration in a child process that can drop all privileges121 * (including capabilities), the main process must remain privileged for122 * cleanup.123 * Child process's cgroup is irrelevant but we place it into child_dst124 * as hacky way to pass information about migration target to the child.125 */126 if (allow ^ (cg_run(child_dst, do_migration_fn, (void *)(size_t)object_pid) == EXIT_SUCCESS))127 goto cleanup;128 129 ret = KSFT_PASS;130 131cleanup:132 if (object_pid > 0) {133 (void)kill(object_pid, SIGTERM);134 (void)clone_reap(object_pid, WEXITED);135 }136 137 cg_destroy(child_dst);138 free(child_dst_procs);139 free(child_dst);140 141 cg_destroy(child_src);142 free(child_src_procs);143 free(child_src);144 145 cg_destroy(parent);146 free(parent_procs);147 free(parent);148 149 return ret;150}151 152static int test_cpuset_perms_object_allow(const char *root)153{154 return test_cpuset_perms_object(root, true);155}156 157static int test_cpuset_perms_object_deny(const char *root)158{159 return test_cpuset_perms_object(root, false);160}161 162/*163 * Migrate a process between parent and child implicitely164 * Implicit migration happens when a controller is enabled/disabled.165 *166 */167static int test_cpuset_perms_subtree(const char *root)168{169 char *parent = NULL, *child = NULL;170 char *parent_procs = NULL, *parent_subctl = NULL, *child_procs = NULL;171 const uid_t test_euid = TEST_UID;172 int object_pid = 0;173 int ret = KSFT_FAIL;174 175 parent = cg_name(root, "cpuset_test_0");176 if (!parent)177 goto cleanup;178 parent_procs = cg_name(parent, "cgroup.procs");179 if (!parent_procs)180 goto cleanup;181 parent_subctl = cg_name(parent, "cgroup.subtree_control");182 if (!parent_subctl)183 goto cleanup;184 if (cg_create(parent))185 goto cleanup;186 187 child = cg_name(parent, "cpuset_test_1");188 if (!child)189 goto cleanup;190 child_procs = cg_name(child, "cgroup.procs");191 if (!child_procs)192 goto cleanup;193 if (cg_create(child))194 goto cleanup;195 196 /* Enable permissions as in a delegated subtree */197 if (chown(parent_procs, test_euid, -1) ||198 chown(parent_subctl, test_euid, -1) ||199 chown(child_procs, test_euid, -1))200 goto cleanup;201 202 /* Put a privileged child in the subtree and modify controller state203 * from an unprivileged process, the main process remains privileged204 * for cleanup.205 * The unprivileged child runs in subtree too to avoid parent and206 * internal-node constraing violation.207 */208 object_pid = cg_run_nowait(child, idle_process_fn, NULL);209 if (object_pid < 0)210 goto cleanup;211 212 if (cg_run(child, do_controller_fn, parent) != EXIT_SUCCESS)213 goto cleanup;214 215 ret = KSFT_PASS;216 217cleanup:218 if (object_pid > 0) {219 (void)kill(object_pid, SIGTERM);220 (void)clone_reap(object_pid, WEXITED);221 }222 223 cg_destroy(child);224 free(child_procs);225 free(child);226 227 cg_destroy(parent);228 free(parent_subctl);229 free(parent_procs);230 free(parent);231 232 return ret;233}234 235 236#define T(x) { x, #x }237struct cpuset_test {238 int (*fn)(const char *root);239 const char *name;240} tests[] = {241 T(test_cpuset_perms_object_allow),242 T(test_cpuset_perms_object_deny),243 T(test_cpuset_perms_subtree),244};245#undef T246 247int main(int argc, char *argv[])248{249 char root[PATH_MAX];250 int i, ret = EXIT_SUCCESS;251 252 if (cg_find_unified_root(root, sizeof(root), NULL))253 ksft_exit_skip("cgroup v2 isn't mounted\n");254 255 if (cg_read_strstr(root, "cgroup.subtree_control", "cpuset"))256 if (cg_write(root, "cgroup.subtree_control", "+cpuset"))257 ksft_exit_skip("Failed to set cpuset controller\n");258 259 for (i = 0; i < ARRAY_SIZE(tests); i++) {260 switch (tests[i].fn(root)) {261 case KSFT_PASS:262 ksft_test_result_pass("%s\n", tests[i].name);263 break;264 case KSFT_SKIP:265 ksft_test_result_skip("%s\n", tests[i].name);266 break;267 default:268 ret = EXIT_FAILURE;269 ksft_test_result_fail("%s\n", tests[i].name);270 break;271 }272 }273 274 return ret;275}276