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      1 /*
      2  * Copyright (c) Huawei Technologies Co., Ltd., 2015
      3  * This program is free software; you can redistribute it and/or modify
      4  * it under the terms of the GNU General Public License as published by
      5  * the Free Software Foundation; either version 2 of the License, or
      6  *  (at your option) any later version.
      7  *
      8  * This program is distributed in the hope that it will be useful,
      9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
     11  * the GNU General Public License for more details.
     12  */
     13 
     14 /*
     15  * Verify that:
     16  * The kernel imposes a limit of at least 32 nested levels on user namespaces.
     17  */
     18 
     19 #define _GNU_SOURCE
     20 #include <sys/wait.h>
     21 #include <assert.h>
     22 #include <stdio.h>
     23 #include <stdlib.h>
     24 #include <unistd.h>
     25 #include <string.h>
     26 #include <errno.h>
     27 #include "userns_helper.h"
     28 #include "test.h"
     29 
     30 #define MAXNEST 32
     31 
     32 char *TCID = "userns07";
     33 int TST_TOTAL = 1;
     34 
     35 static void setup(void)
     36 {
     37 	check_newuser();
     38 	tst_tmpdir();
     39 	TST_CHECKPOINT_INIT(NULL);
     40 }
     41 
     42 static void cleanup(void)
     43 {
     44 	tst_rmdir();
     45 }
     46 
     47 static int child_fn1(void *arg)
     48 {
     49 	pid_t cpid1;
     50 	long level = (long)arg;
     51 	int status;
     52 	int parentuid;
     53 	int parentgid;
     54 
     55 	TST_SAFE_CHECKPOINT_WAIT(NULL, 0);
     56 
     57 	if (level == MAXNEST)
     58 		return 0;
     59 	cpid1 = ltp_clone_quick(CLONE_NEWUSER | SIGCHLD,
     60 		(void *)child_fn1, (void *)(level + 1));
     61 	if (cpid1 < 0) {
     62 		printf("level %ld:unexpected error: (%d) %s\n",
     63 			level, errno, strerror(errno));
     64 		return 1;
     65 	}
     66 
     67 	parentuid = geteuid();
     68 	parentgid = getegid();
     69 
     70 	updatemap(cpid1, UID_MAP, 0, parentuid, NULL);
     71 	updatemap(cpid1, GID_MAP, 0, parentgid, NULL);
     72 
     73 	TST_SAFE_CHECKPOINT_WAKE(cleanup, 0);
     74 
     75 	if (waitpid(cpid1, &status, 0) == -1)
     76 		return 1;
     77 
     78 	if (WIFEXITED(status) && WEXITSTATUS(status) != 0) {
     79 		printf("child exited abnormally\n");
     80 		return 1;
     81 	} else if (WIFSIGNALED(status)) {
     82 		printf("child was killed with signal = %d", WTERMSIG(status));
     83 		return 1;
     84 	}
     85 	return 0;
     86 }
     87 
     88 static void test_max_nest(void)
     89 {
     90 	pid_t cpid1;
     91 	int parentuid;
     92 	int parentgid;
     93 	int fd;
     94 	char path[BUFSIZ];
     95 
     96 	cpid1 = ltp_clone_quick(CLONE_NEWUSER | SIGCHLD,
     97 		(void *)child_fn1, (void *)0);
     98 	if (cpid1 < 0)
     99 		tst_brkm(TBROK | TERRNO, cleanup, "clone failed");
    100 
    101 	parentuid = geteuid();
    102 	parentgid = getegid();
    103 
    104 	if (access("/proc/self/setgroups", F_OK) == 0) {
    105 		sprintf(path, "/proc/%d/setgroups", cpid1);
    106 		fd = SAFE_OPEN(cleanup, path, O_WRONLY, 0644);
    107 		SAFE_WRITE(cleanup, 1, fd, "deny", 4);
    108 		SAFE_CLOSE(cleanup, fd);
    109 	}
    110 
    111 	updatemap(cpid1, UID_MAP, 0, parentuid, cleanup);
    112 	updatemap(cpid1, GID_MAP, 0, parentgid, cleanup);
    113 
    114 	TST_SAFE_CHECKPOINT_WAKE(cleanup, 0);
    115 	tst_record_childstatus(cleanup, cpid1);
    116 }
    117 
    118 int main(int argc, char *argv[])
    119 {
    120 	int lc;
    121 
    122 	setup();
    123 	tst_parse_opts(argc, argv, NULL, NULL);
    124 
    125 	for (lc = 0; TEST_LOOPING(lc); lc++) {
    126 		tst_count = 0;
    127 		test_max_nest();
    128 	}
    129 
    130 	cleanup();
    131 	tst_exit();
    132 }
    133 
    134