1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) 2018 FUJITSU LIMITED. All rights reserved.
4 * Author: Xiao Yang <yangx.jy@cn.fujitsu.com>
5 */
6 /*
7 * Description:
8 * Check various errnos for mlock2(2) since kernel v2.6.9:
9 * 1) mlock2() fails and returns EINVAL if unknown flag is specified.
10 * 2) mlock2() fails and returns ENOMEM if the caller is not
11 * privileged(CAP_IPC_LOCK) and tries to lock more memory than the
12 * RLIMIT_MEMLOCK limit.
13 * 3) mlock2() fails and returns EPERM if the caller is not
14 * privileged(CAP_IPC_LOCK) and its RLIMIT_MEMLOCK limit is 0.
15 * 4) mlock2() fails and returns ENOMEM if some of the specified address
16 * range does not correspond to mapped pages in the address space
17 * of the caller.
18 */
19 #include <errno.h>
20 #include <unistd.h>
21 #include <sys/mman.h>
22 #include <sys/time.h>
23 #include <sys/resource.h>
24 #include <pwd.h>
25
26 #include "tst_test.h"
27 #include "lapi/syscalls.h"
28
29 #define PAGES 8
30
31 static size_t pgsz;
32 static size_t max_sz1, max_sz2;
33 static char *addr, *unmapped_addr;
34 static struct passwd *nobody;
35
36 static struct tcase {
37 char **taddr;
38 int flag;
39 size_t *max_size;
40 /* 1: nobody 0: root */
41 int user;
42 int exp_err;
43 } tcases[] = {
44 {&addr, -1, NULL, 0, EINVAL},
45 {&addr, 0, &max_sz1, 1, ENOMEM},
46 {&addr, 0, &max_sz2, 1, EPERM},
47 {&unmapped_addr, 0, NULL, 0, ENOMEM},
48 };
49
verify_mlock2(unsigned int n)50 static void verify_mlock2(unsigned int n)
51 {
52 struct tcase *tc = &tcases[n];
53 struct rlimit orig_limit, new_limit;
54
55 if (tc->user) {
56 SAFE_GETRLIMIT(RLIMIT_MEMLOCK, &orig_limit);
57 new_limit.rlim_cur = *tc->max_size;
58 new_limit.rlim_max = *tc->max_size;
59 SAFE_SETRLIMIT(RLIMIT_MEMLOCK, &new_limit);
60 SAFE_SETEUID(nobody->pw_uid);
61 }
62
63 TEST(tst_syscall(__NR_mlock2, *tc->taddr, pgsz, tc->flag));
64 if (TST_RET != -1) {
65 tst_res(TFAIL, "mlock2() succeeded");
66 SAFE_MUNLOCK(*tc->taddr, pgsz);
67 goto end;
68 }
69
70 if (TST_ERR != tc->exp_err) {
71 tst_res(TFAIL | TTERRNO,
72 "mlock2() failed unexpectedly, expected %s",
73 tst_strerrno(tc->exp_err));
74 } else {
75 tst_res(TPASS | TTERRNO, "mlock2() failed as expected");
76 }
77
78 end:
79 if (tc->user) {
80 SAFE_SETEUID(0);
81 SAFE_SETRLIMIT(RLIMIT_MEMLOCK, &orig_limit);
82 }
83 }
84
setup(void)85 static void setup(void)
86 {
87 pgsz = getpagesize();
88 nobody = SAFE_GETPWNAM("nobody");
89
90 addr = SAFE_MMAP(NULL, pgsz, PROT_WRITE,
91 MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
92 unmapped_addr = SAFE_MMAP(NULL, pgsz * PAGES, PROT_READ,
93 MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
94 SAFE_MUNMAP(unmapped_addr, pgsz * PAGES);
95 unmapped_addr = unmapped_addr + pgsz * PAGES / 2;
96
97 max_sz1 = pgsz - 1;
98 }
99
cleanup(void)100 static void cleanup(void)
101 {
102 if (addr)
103 SAFE_MUNMAP(addr, pgsz);
104 }
105
106 static struct tst_test test = {
107 .tcnt = ARRAY_SIZE(tcases),
108 .test = verify_mlock2,
109 .setup = setup,
110 .cleanup = cleanup,
111 .needs_root = 1,
112 .min_kver = "2.6.9",
113 };
114