457 lines · c
1// SPDX-License-Identifier: GPL-2.02#define _GNU_SOURCE3 4#include <cap-ng.h>5#include <linux/capability.h>6#include <stdbool.h>7#include <string.h>8#include <stdio.h>9#include <fcntl.h>10#include <errno.h>11#include <stdarg.h>12#include <sched.h>13#include <sys/mount.h>14#include <limits.h>15#include <libgen.h>16#include <malloc.h>17#include <sys/wait.h>18#include <sys/prctl.h>19#include <sys/stat.h>20 21#include "../kselftest.h"22 23static int nerrs;24static pid_t mpid; /* main() pid is used to avoid duplicate test counts */25 26static void vmaybe_write_file(bool enoent_ok, char *filename, char *fmt, va_list ap)27{28 char buf[4096];29 int fd;30 ssize_t written;31 int buf_len;32 33 buf_len = vsnprintf(buf, sizeof(buf), fmt, ap);34 if (buf_len < 0)35 ksft_exit_fail_msg("vsnprintf failed - %s\n", strerror(errno));36 37 if (buf_len >= sizeof(buf))38 ksft_exit_fail_msg("vsnprintf output truncated\n");39 40 41 fd = open(filename, O_WRONLY);42 if (fd < 0) {43 if ((errno == ENOENT) && enoent_ok)44 return;45 ksft_exit_fail_msg("open of %s failed - %s\n",46 filename, strerror(errno));47 }48 written = write(fd, buf, buf_len);49 if (written != buf_len) {50 if (written >= 0) {51 ksft_exit_fail_msg("short write to %s\n", filename);52 } else {53 ksft_exit_fail_msg("write to %s failed - %s\n",54 filename, strerror(errno));55 }56 }57 if (close(fd) != 0) {58 ksft_exit_fail_msg("close of %s failed - %s\n",59 filename, strerror(errno));60 }61}62 63static void maybe_write_file(char *filename, char *fmt, ...)64{65 va_list ap;66 67 va_start(ap, fmt);68 vmaybe_write_file(true, filename, fmt, ap);69 va_end(ap);70}71 72static void write_file(char *filename, char *fmt, ...)73{74 va_list ap;75 76 va_start(ap, fmt);77 vmaybe_write_file(false, filename, fmt, ap);78 va_end(ap);79}80 81static bool create_and_enter_ns(uid_t inner_uid)82{83 uid_t outer_uid;84 gid_t outer_gid;85 int i, ret;86 bool have_outer_privilege;87 88 outer_uid = getuid();89 outer_gid = getgid();90 91 if (outer_uid == 0 && unshare(CLONE_NEWNS) == 0) {92 ksft_print_msg("[NOTE]\tUsing global UIDs for tests\n");93 if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) != 0)94 ksft_exit_fail_msg("PR_SET_KEEPCAPS - %s\n",95 strerror(errno));96 if (setresuid(inner_uid, inner_uid, -1) != 0)97 ksft_exit_fail_msg("setresuid - %s\n", strerror(errno));98 99 // Re-enable effective caps100 ret = capng_get_caps_process();101 if (ret == -1)102 ksft_exit_fail_msg("capng_get_caps_process failed\n");103 104 for (i = 0; i < CAP_LAST_CAP; i++)105 if (capng_have_capability(CAPNG_PERMITTED, i))106 capng_update(CAPNG_ADD, CAPNG_EFFECTIVE, i);107 if (capng_apply(CAPNG_SELECT_CAPS) != 0)108 ksft_exit_fail_msg(109 "capng_apply - %s\n", strerror(errno));110 111 have_outer_privilege = true;112 } else if (unshare(CLONE_NEWUSER | CLONE_NEWNS) == 0) {113 ksft_print_msg("[NOTE]\tUsing a user namespace for tests\n");114 maybe_write_file("/proc/self/setgroups", "deny");115 write_file("/proc/self/uid_map", "%d %d 1", inner_uid, outer_uid);116 write_file("/proc/self/gid_map", "0 %d 1", outer_gid);117 118 have_outer_privilege = false;119 } else {120 ksft_exit_skip("must be root or be able to create a userns\n");121 }122 123 if (mount("none", "/", NULL, MS_REC | MS_PRIVATE, NULL) != 0)124 ksft_exit_fail_msg("remount everything private - %s\n",125 strerror(errno));126 127 return have_outer_privilege;128}129 130static void chdir_to_tmpfs(void)131{132 char cwd[PATH_MAX];133 if (getcwd(cwd, sizeof(cwd)) != cwd)134 ksft_exit_fail_msg("getcwd - %s\n", strerror(errno));135 136 if (mount("private_tmp", ".", "tmpfs", 0, "mode=0777") != 0)137 ksft_exit_fail_msg("mount private tmpfs - %s\n",138 strerror(errno));139 140 if (chdir(cwd) != 0)141 ksft_exit_fail_msg("chdir to private tmpfs - %s\n",142 strerror(errno));143}144 145static void copy_fromat_to(int fromfd, const char *fromname, const char *toname)146{147 int from = openat(fromfd, fromname, O_RDONLY);148 if (from == -1)149 ksft_exit_fail_msg("open copy source - %s\n", strerror(errno));150 151 int to = open(toname, O_CREAT | O_WRONLY | O_EXCL, 0700);152 153 while (true) {154 char buf[4096];155 ssize_t sz = read(from, buf, sizeof(buf));156 if (sz == 0)157 break;158 if (sz < 0)159 ksft_exit_fail_msg("read - %s\n", strerror(errno));160 161 if (write(to, buf, sz) != sz)162 /* no short writes on tmpfs */163 ksft_exit_fail_msg("write - %s\n", strerror(errno));164 }165 166 close(from);167 close(to);168}169 170static bool fork_wait(void)171{172 pid_t child = fork();173 if (child == 0) {174 nerrs = 0;175 return true;176 } else if (child > 0) {177 int status;178 if (waitpid(child, &status, 0) != child ||179 !WIFEXITED(status)) {180 ksft_print_msg("Child died\n");181 nerrs++;182 } else if (WEXITSTATUS(status) != 0) {183 ksft_print_msg("Child failed\n");184 nerrs++;185 } else {186 /* don't print this message for mpid */187 if (getpid() != mpid)188 ksft_test_result_pass("Passed\n");189 }190 return false;191 } else {192 ksft_exit_fail_msg("fork - %s\n", strerror(errno));193 return false;194 }195}196 197static void exec_other_validate_cap(const char *name,198 bool eff, bool perm, bool inh, bool ambient)199{200 execl(name, name, (eff ? "1" : "0"),201 (perm ? "1" : "0"), (inh ? "1" : "0"), (ambient ? "1" : "0"),202 NULL);203 ksft_exit_fail_msg("execl - %s\n", strerror(errno));204}205 206static void exec_validate_cap(bool eff, bool perm, bool inh, bool ambient)207{208 exec_other_validate_cap("./validate_cap", eff, perm, inh, ambient);209}210 211static int do_tests(int uid, const char *our_path)212{213 int ret;214 bool have_outer_privilege = create_and_enter_ns(uid);215 216 int ourpath_fd = open(our_path, O_RDONLY | O_DIRECTORY);217 if (ourpath_fd == -1)218 ksft_exit_fail_msg("open '%s' - %s\n",219 our_path, strerror(errno));220 221 chdir_to_tmpfs();222 223 copy_fromat_to(ourpath_fd, "validate_cap", "validate_cap");224 225 if (have_outer_privilege) {226 uid_t gid = getegid();227 228 copy_fromat_to(ourpath_fd, "validate_cap",229 "validate_cap_suidroot");230 if (chown("validate_cap_suidroot", 0, -1) != 0)231 ksft_exit_fail_msg("chown - %s\n", strerror(errno));232 if (chmod("validate_cap_suidroot", S_ISUID | 0700) != 0)233 ksft_exit_fail_msg("chmod - %s\n", strerror(errno));234 235 copy_fromat_to(ourpath_fd, "validate_cap",236 "validate_cap_suidnonroot");237 if (chown("validate_cap_suidnonroot", uid + 1, -1) != 0)238 ksft_exit_fail_msg("chown - %s\n", strerror(errno));239 if (chmod("validate_cap_suidnonroot", S_ISUID | 0700) != 0)240 ksft_exit_fail_msg("chmod - %s\n", strerror(errno));241 242 copy_fromat_to(ourpath_fd, "validate_cap",243 "validate_cap_sgidroot");244 if (chown("validate_cap_sgidroot", -1, 0) != 0)245 ksft_exit_fail_msg("chown - %s\n", strerror(errno));246 if (chmod("validate_cap_sgidroot", S_ISGID | 0710) != 0)247 ksft_exit_fail_msg("chmod - %s\n", strerror(errno));248 249 copy_fromat_to(ourpath_fd, "validate_cap",250 "validate_cap_sgidnonroot");251 if (chown("validate_cap_sgidnonroot", -1, gid + 1) != 0)252 ksft_exit_fail_msg("chown - %s\n", strerror(errno));253 if (chmod("validate_cap_sgidnonroot", S_ISGID | 0710) != 0)254 ksft_exit_fail_msg("chmod - %s\n", strerror(errno));255 }256 257 ret = capng_get_caps_process();258 if (ret == -1)259 ksft_exit_fail_msg("capng_get_caps_process failed\n");260 261 /* Make sure that i starts out clear */262 capng_update(CAPNG_DROP, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);263 if (capng_apply(CAPNG_SELECT_CAPS) != 0)264 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));265 266 if (uid == 0) {267 ksft_print_msg("[RUN]\tRoot => ep\n");268 if (fork_wait())269 exec_validate_cap(true, true, false, false);270 } else {271 ksft_print_msg("[RUN]\tNon-root => no caps\n");272 if (fork_wait())273 exec_validate_cap(false, false, false, false);274 }275 276 ksft_print_msg("Check cap_ambient manipulation rules\n");277 278 /* We should not be able to add ambient caps yet. */279 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != -1 || errno != EPERM) {280 if (errno == EINVAL)281 ksft_test_result_fail(282 "PR_CAP_AMBIENT_RAISE isn't supported\n");283 else284 ksft_test_result_fail(285 "PR_CAP_AMBIENT_RAISE should have failed eith EPERM on a non-inheritable cap\n");286 return 1;287 }288 ksft_test_result_pass(289 "PR_CAP_AMBIENT_RAISE failed on non-inheritable cap\n");290 291 capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_RAW);292 capng_update(CAPNG_DROP, CAPNG_PERMITTED, CAP_NET_RAW);293 capng_update(CAPNG_DROP, CAPNG_EFFECTIVE, CAP_NET_RAW);294 if (capng_apply(CAPNG_SELECT_CAPS) != 0)295 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));296 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_RAW, 0, 0, 0) != -1 || errno != EPERM) {297 ksft_test_result_fail(298 "PR_CAP_AMBIENT_RAISE should have failed on a non-permitted cap\n");299 return 1;300 }301 ksft_test_result_pass(302 "PR_CAP_AMBIENT_RAISE failed on non-permitted cap\n");303 304 capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);305 if (capng_apply(CAPNG_SELECT_CAPS) != 0)306 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));307 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) {308 ksft_test_result_fail(309 "PR_CAP_AMBIENT_RAISE should have succeeded\n");310 return 1;311 }312 ksft_test_result_pass("PR_CAP_AMBIENT_RAISE worked\n");313 314 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 1) {315 ksft_test_result_fail("PR_CAP_AMBIENT_IS_SET is broken\n");316 return 1;317 }318 319 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_CLEAR_ALL, 0, 0, 0, 0) != 0)320 ksft_exit_fail_msg("PR_CAP_AMBIENT_CLEAR_ALL - %s\n",321 strerror(errno));322 323 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) {324 ksft_test_result_fail(325 "PR_CAP_AMBIENT_CLEAR_ALL didn't work\n");326 return 1;327 }328 329 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0)330 ksft_exit_fail_msg("PR_CAP_AMBIENT_RAISE - %s\n",331 strerror(errno));332 333 capng_update(CAPNG_DROP, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);334 if (capng_apply(CAPNG_SELECT_CAPS) != 0)335 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));336 337 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) {338 ksft_test_result_fail("Dropping I should have dropped A\n");339 return 1;340 }341 342 ksft_test_result_pass("Basic manipulation appears to work\n");343 344 capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);345 if (capng_apply(CAPNG_SELECT_CAPS) != 0)346 ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));347 if (uid == 0) {348 ksft_print_msg("[RUN]\tRoot +i => eip\n");349 if (fork_wait())350 exec_validate_cap(true, true, true, false);351 } else {352 ksft_print_msg("[RUN]\tNon-root +i => i\n");353 if (fork_wait())354 exec_validate_cap(false, false, true, false);355 }356 357 if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0)358 ksft_exit_fail_msg("PR_CAP_AMBIENT_RAISE - %s\n",359 strerror(errno));360 361 ksft_print_msg("[RUN]\tUID %d +ia => eipa\n", uid);362 if (fork_wait())363 exec_validate_cap(true, true, true, true);364 365 /* The remaining tests need real privilege */366 367 if (!have_outer_privilege) {368 ksft_test_result_skip("SUID/SGID tests (needs privilege)\n");369 goto done;370 }371 372 if (uid == 0) {373 ksft_print_msg("[RUN]\tRoot +ia, suidroot => eipa\n");374 if (fork_wait())375 exec_other_validate_cap("./validate_cap_suidroot",376 true, true, true, true);377 378 ksft_print_msg("[RUN]\tRoot +ia, suidnonroot => ip\n");379 if (fork_wait())380 exec_other_validate_cap("./validate_cap_suidnonroot",381 false, true, true, false);382 383 ksft_print_msg("[RUN]\tRoot +ia, sgidroot => eipa\n");384 if (fork_wait())385 exec_other_validate_cap("./validate_cap_sgidroot",386 true, true, true, true);387 388 if (fork_wait()) {389 ksft_print_msg(390 "[RUN]\tRoot, gid != 0, +ia, sgidroot => eip\n");391 if (setresgid(1, 1, 1) != 0)392 ksft_exit_fail_msg("setresgid - %s\n",393 strerror(errno));394 exec_other_validate_cap("./validate_cap_sgidroot",395 true, true, true, false);396 }397 398 ksft_print_msg("[RUN]\tRoot +ia, sgidnonroot => eip\n");399 if (fork_wait())400 exec_other_validate_cap("./validate_cap_sgidnonroot",401 true, true, true, false);402 } else {403 ksft_print_msg("[RUN]\tNon-root +ia, sgidnonroot => i\n");404 if (fork_wait())405 exec_other_validate_cap("./validate_cap_sgidnonroot",406 false, false, true, false);407 408 if (fork_wait()) {409 ksft_print_msg("[RUN]\tNon-root +ia, sgidroot => i\n");410 if (setresgid(1, 1, 1) != 0)411 ksft_exit_fail_msg("setresgid - %s\n",412 strerror(errno));413 exec_other_validate_cap("./validate_cap_sgidroot",414 false, false, true, false);415 }416 }417 418done:419 ksft_print_cnts();420 return nerrs ? 1 : 0;421}422 423int main(int argc, char **argv)424{425 char *tmp1, *tmp2, *our_path;426 427 /* Find our path */428 tmp1 = strdup(argv[0]);429 if (!tmp1)430 ksft_exit_fail_msg("strdup - %s\n", strerror(errno));431 tmp2 = dirname(tmp1);432 our_path = strdup(tmp2);433 if (!our_path)434 ksft_exit_fail_msg("strdup - %s\n", strerror(errno));435 free(tmp1);436 437 mpid = getpid();438 439 if (fork_wait()) {440 ksft_print_header();441 ksft_set_plan(12);442 ksft_print_msg("[RUN]\t+++ Tests with uid == 0 +++\n");443 return do_tests(0, our_path);444 }445 446 ksft_print_msg("==================================================\n");447 448 if (fork_wait()) {449 ksft_print_header();450 ksft_set_plan(9);451 ksft_print_msg("[RUN]\t+++ Tests with uid != 0 +++\n");452 return do_tests(1, our_path);453 }454 455 return nerrs ? 1 : 0;456}457