129 lines
2.8 KiB
C
129 lines
2.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (c) 2017 Fujitsu Ltd.
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* Author: Xiao Yang <yangx.jy@cn.fujitsu.com>
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*/
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/*
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* Description:
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* fcntl(2) manpage states that an unprivileged user could not set the
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* pipe capacity above the limit in /proc/sys/fs/pipe-max-size. However,
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* an unprivileged user could create a pipe whose initial capacity exceeds
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* the limit. We add a regression test to check that pipe-max-size caps
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* the initial allocation for a new pipe for unprivileged users, but not
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* for privileged users.
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*
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* This kernel bug has been fixed by:
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*
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* commit 086e774a57fba4695f14383c0818994c0b31da7c
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* Author: Michael Kerrisk (man-pages) <mtk.manpages@gmail.com>
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* Date: Tue Oct 11 13:53:43 2016 -0700
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*
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* pipe: cap initial pipe capacity according to pipe-max-size limit
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*/
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#include <errno.h>
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#include <sys/types.h>
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#include <pwd.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include "lapi/fcntl.h"
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#include "tst_test.h"
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static int pipe_max_unpriv;
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static int test_max_unpriv;
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static int test_max_priv;
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static struct passwd *pw;
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static struct tcase {
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int *exp_sz;
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int exp_usr;
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char *des;
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} tcases[] = {
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{&test_max_unpriv, 1, "an unprivileged user"},
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{&test_max_priv, 0, "a privileged user"}
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};
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static void setup(void)
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{
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test_max_unpriv = getpagesize();
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test_max_priv = test_max_unpriv * 16;
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if (!access("/proc/sys/fs/pipe-max-size", F_OK)) {
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SAFE_FILE_SCANF("/proc/sys/fs/pipe-max-size", "%d",
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&pipe_max_unpriv);
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SAFE_FILE_PRINTF("/proc/sys/fs/pipe-max-size", "%d",
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test_max_unpriv);
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} else {
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tst_brk(TCONF, "/proc/sys/fs/pipe-max-size doesn't exist");
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}
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pw = SAFE_GETPWNAM("nobody");
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}
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static void cleanup(void)
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{
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SAFE_FILE_PRINTF("/proc/sys/fs/pipe-max-size", "%d", pipe_max_unpriv);
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}
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static int verify_pipe_size(int exp_pip_sz, char *desp)
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{
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int get_size;
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int fds[2];
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SAFE_PIPE(fds);
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get_size = fcntl(fds[1], F_GETPIPE_SZ);
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if (get_size == -1) {
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tst_res(TFAIL | TERRNO, "fcntl(2) with F_GETPIPE_SZ failed");
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goto end;
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}
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if (get_size != exp_pip_sz) {
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tst_res(TFAIL, "%s init the capacity of a pipe to %d "
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"unexpectedly, expected %d", desp, get_size,
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exp_pip_sz);
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} else {
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tst_res(TPASS, "%s init the capacity of a pipe to %d "
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"successfully", desp, exp_pip_sz);
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}
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end:
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if (fds[0] > 0)
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SAFE_CLOSE(fds[0]);
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if (fds[1] > 0)
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SAFE_CLOSE(fds[1]);
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exit(0);
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}
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static void do_test(unsigned int n)
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{
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struct tcase *tc = &tcases[n];
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if (!SAFE_FORK()) {
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if (tc->exp_usr)
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SAFE_SETUID(pw->pw_uid);
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verify_pipe_size(*tc->exp_sz, tc->des);
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}
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tst_reap_children();
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}
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static struct tst_test test = {
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.min_kver = "2.6.35",
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.needs_root = 1,
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.forks_child = 1,
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.tcnt = ARRAY_SIZE(tcases),
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.setup = setup,
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.cleanup = cleanup,
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.test = do_test,
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.tags = (const struct tst_tag[]) {
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{"linux-git", "086e774a57fb"},
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{}
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}
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};
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