103 lines
2.5 KiB
C
103 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (c) International Business Machines Corp., 2001
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* Copyright (c) 2018 Xiao Yang <yangx.jy@cn.fujitsu.com>
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*/
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/*
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* DESCRIPTION
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* 1) Call sysctl(2) as a root user, and attempt to write data
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* to the kernel_table[]. Since the table does not have write
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* permissions even for the root, it should fail EPERM.
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* 2) Call sysctl(2) as a non-root user, and attempt to write data
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* to the kernel_table[]. Since the table does not have write
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* permission for the regular user, it should fail with EPERM.
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*
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* NOTE: There is a documentation bug in 2.6.33-rc1 where unfortunately
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* the behavior of sysctl(2) isn't properly documented, as discussed
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* in detail in the following thread:
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* http://sourceforge.net/mailarchive/message.php?msg_name=4B7BA24F.2010705%40linux.vnet.ibm.com.
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*
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* The documentation bug is filed as:
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* https://bugzilla.kernel.org/show_bug.cgi?id=15446 . If you want the
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* message removed, please ask your fellow kernel maintainer to fix their
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* documentation.
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*
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* Thanks!
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* -Ngie
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*/
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <stdio.h>
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#include <errno.h>
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#include <unistd.h>
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#include <linux/unistd.h>
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#include <linux/sysctl.h>
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#include <pwd.h>
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#include "tst_test.h"
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#include "lapi/syscalls.h"
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static int exp_eno;
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static void verify_sysctl(void)
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{
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char *osname = "Linux";
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int name[] = {CTL_KERN, KERN_OSTYPE};
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struct __sysctl_args args = {
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.name = name,
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.nlen = ARRAY_SIZE(name),
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.newval = osname,
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.newlen = sizeof(osname),
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};
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TEST(tst_syscall(__NR__sysctl, &args));
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if (TST_RET != -1) {
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tst_res(TFAIL, "sysctl(2) succeeded unexpectedly");
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return;
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}
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if (TST_ERR == exp_eno) {
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tst_res(TPASS | TTERRNO, "Got expected error");
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} else {
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tst_res(TFAIL | TTERRNO, "Got unexpected error, expected %s",
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tst_strerrno(exp_eno));
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}
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}
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static void setup(void)
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{
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if ((tst_kvercmp(2, 6, 32)) <= 0) {
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exp_eno = EPERM;
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} else {
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/* Look above this warning. */
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tst_res(TINFO,
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"this test's results are based on potentially undocumented behavior in the kernel. read the NOTE in the source file for more details");
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exp_eno = EACCES;
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}
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}
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static void do_test(void)
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{
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pid_t pid;
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struct passwd *ltpuser;
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pid = SAFE_FORK();
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if (!pid) {
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ltpuser = SAFE_GETPWNAM("nobody");
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SAFE_SETUID(ltpuser->pw_uid);
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verify_sysctl();
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} else {
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verify_sysctl();
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tst_reap_children();
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}
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}
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static struct tst_test test = {
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.needs_root = 1,
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.forks_child = 1,
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.setup = setup,
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.test_all = do_test,
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};
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