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      1 /*
      2  *  This program is free software; you can redistribute it and/or modify
      3  *  it under the terms of the GNU General Public License version 2.
      4  *
      5  *  This program is distributed in the hope that it will be useful,
      6  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
      7  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      8  *  GNU General Public License for more details.
      9  *
     10  * Test that the mlock() function sets errno = EPERM if the calling process
     11  * does not have the appropriate privilege to perform the requested operation
     12  * (Linux 2.6.9 and later) and its RLIMIT_MEMLOCK soft resource limit set to 0.
     13  */
     14 
     15 #define _XOPEN_SOURCE 600
     16 
     17 #include <sys/mman.h>
     18 #include <stdio.h>
     19 #include <unistd.h>
     20 #include <stdlib.h>
     21 #include <errno.h>
     22 #include <sys/types.h>
     23 #include <pwd.h>
     24 #include <string.h>
     25 #include <sys/resource.h>
     26 #include "posixtest.h"
     27 
     28 #define BUFSIZE 8
     29 
     30 /** Set the euid of this process to a non-root uid */
     31 int set_nonroot()
     32 {
     33 	struct passwd *pw;
     34 	struct rlimit rlim;
     35 	int ret = 0;
     36 
     37 	setpwent();
     38 	/* search for the first user which is non root */
     39 	while ((pw = getpwent()) != NULL)
     40 		if (strcmp(pw->pw_name, "root"))
     41 			break;
     42 	endpwent();
     43 	if (pw == NULL) {
     44 		printf("There is no other user than current and root.\n");
     45 		return 1;
     46 	}
     47 
     48 	/*
     49 	 * mlock()
     50 	 * EPERM:
     51 	 * (Linux 2.6.9 and later) the caller was not privileged (CAP_IPC_LOCK)
     52 	 * and its RLIMIT_MEMLOCK soft resource limit was 0.
     53 	 */
     54 
     55 	rlim.rlim_cur = 0;
     56 	rlim.rlim_max = 0;
     57 	if ((ret = setrlimit(RLIMIT_MEMLOCK, &rlim)) != 0)
     58 		printf("Failed at setrlimit() return %d \n", ret);
     59 
     60 	if (seteuid(pw->pw_uid) != 0) {
     61 		if (errno == EPERM) {
     62 			printf
     63 			    ("You don't have permission to change your UID.\n");
     64 			return 1;
     65 		}
     66 		perror("An error occurs when calling seteuid()");
     67 		return 1;
     68 	}
     69 
     70 	printf("Testing with user '%s' (uid: %d)\n",
     71 	       pw->pw_name, (int)geteuid());
     72 	return 0;
     73 }
     74 
     75 int main(void)
     76 {
     77 	int result;
     78 	void *ptr;
     79 
     80 	/* This test should be run under standard user permissions */
     81 	if (getuid() == 0) {
     82 		if (set_nonroot() != 0) {
     83 			printf("Cannot run this test as non-root user\n");
     84 			return PTS_UNTESTED;
     85 		}
     86 	}
     87 
     88 	ptr = malloc(BUFSIZE);
     89 	if (ptr == NULL) {
     90 		printf("Can not allocate memory.\n");
     91 		return PTS_UNRESOLVED;
     92 	}
     93 
     94 	result = mlock(ptr, BUFSIZE);
     95 
     96 	if (result == -1 && errno == EPERM) {
     97 		printf("Test PASSED\n");
     98 		return PTS_PASS;
     99 	} else if (result == 0) {
    100 		printf("You have the right to call mlock\n");
    101 		return PTS_FAIL;
    102 	} else {
    103 		perror("Unexpected error");
    104 		return PTS_UNRESOLVED;
    105 	}
    106 
    107 }
    108