linux/tools/testing/selftests/landlock/base_test.c
Günther Noack a1a202a581
selftests/landlock: Test FD passing from restricted to unrestricted processes
A file descriptor created in a restricted process carries Landlock
restrictions with it which will apply even if the same opened file is
used from an unrestricted process.

This change extracts suitable FD-passing helpers from base_test.c and
moves them to common.h. We use the fixture variants from the ftruncate
fixture to exercise the same scenarios as in the open_and_ftruncate
test, but doing the Landlock restriction and open() in a different
process than the ftruncate() call.

Signed-off-by: Günther Noack <gnoack3000@gmail.com>
Link: https://lore.kernel.org/r/20221018182216.301684-9-gnoack3000@gmail.com
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2022-10-19 09:01:46 +02:00

330 lines
9.6 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Landlock tests - Common user space base
*
* Copyright © 2017-2020 Mickaël Salaün <mic@digikod.net>
* Copyright © 2019-2020 ANSSI
*/
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <linux/landlock.h>
#include <string.h>
#include <sys/prctl.h>
#include <sys/socket.h>
#include <sys/types.h>
#include "common.h"
#ifndef O_PATH
#define O_PATH 010000000
#endif
TEST(inconsistent_attr)
{
const long page_size = sysconf(_SC_PAGESIZE);
char *const buf = malloc(page_size + 1);
struct landlock_ruleset_attr *const ruleset_attr = (void *)buf;
ASSERT_NE(NULL, buf);
/* Checks copy_from_user(). */
ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, 0, 0));
/* The size if less than sizeof(struct landlock_attr_enforce). */
ASSERT_EQ(EINVAL, errno);
ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, 1, 0));
ASSERT_EQ(EINVAL, errno);
ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, 7, 0));
ASSERT_EQ(EINVAL, errno);
ASSERT_EQ(-1, landlock_create_ruleset(NULL, 1, 0));
/* The size if less than sizeof(struct landlock_attr_enforce). */
ASSERT_EQ(EFAULT, errno);
ASSERT_EQ(-1, landlock_create_ruleset(
NULL, sizeof(struct landlock_ruleset_attr), 0));
ASSERT_EQ(EFAULT, errno);
ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, page_size + 1, 0));
ASSERT_EQ(E2BIG, errno);
/* Checks minimal valid attribute size. */
ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, 8, 0));
ASSERT_EQ(ENOMSG, errno);
ASSERT_EQ(-1, landlock_create_ruleset(
ruleset_attr,
sizeof(struct landlock_ruleset_attr), 0));
ASSERT_EQ(ENOMSG, errno);
ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, page_size, 0));
ASSERT_EQ(ENOMSG, errno);
/* Checks non-zero value. */
buf[page_size - 2] = '.';
ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, page_size, 0));
ASSERT_EQ(E2BIG, errno);
ASSERT_EQ(-1, landlock_create_ruleset(ruleset_attr, page_size + 1, 0));
ASSERT_EQ(E2BIG, errno);
free(buf);
}
TEST(abi_version)
{
const struct landlock_ruleset_attr ruleset_attr = {
.handled_access_fs = LANDLOCK_ACCESS_FS_READ_FILE,
};
ASSERT_EQ(3, landlock_create_ruleset(NULL, 0,
LANDLOCK_CREATE_RULESET_VERSION));
ASSERT_EQ(-1, landlock_create_ruleset(&ruleset_attr, 0,
LANDLOCK_CREATE_RULESET_VERSION));
ASSERT_EQ(EINVAL, errno);
ASSERT_EQ(-1, landlock_create_ruleset(NULL, sizeof(ruleset_attr),
LANDLOCK_CREATE_RULESET_VERSION));
ASSERT_EQ(EINVAL, errno);
ASSERT_EQ(-1,
landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr),
LANDLOCK_CREATE_RULESET_VERSION));
ASSERT_EQ(EINVAL, errno);
ASSERT_EQ(-1, landlock_create_ruleset(NULL, 0,
LANDLOCK_CREATE_RULESET_VERSION |
1 << 31));
ASSERT_EQ(EINVAL, errno);
}
/* Tests ordering of syscall argument checks. */
TEST(create_ruleset_checks_ordering)
{
const int last_flag = LANDLOCK_CREATE_RULESET_VERSION;
const int invalid_flag = last_flag << 1;
int ruleset_fd;
const struct landlock_ruleset_attr ruleset_attr = {
.handled_access_fs = LANDLOCK_ACCESS_FS_READ_FILE,
};
/* Checks priority for invalid flags. */
ASSERT_EQ(-1, landlock_create_ruleset(NULL, 0, invalid_flag));
ASSERT_EQ(EINVAL, errno);
ASSERT_EQ(-1, landlock_create_ruleset(&ruleset_attr, 0, invalid_flag));
ASSERT_EQ(EINVAL, errno);
ASSERT_EQ(-1, landlock_create_ruleset(NULL, sizeof(ruleset_attr),
invalid_flag));
ASSERT_EQ(EINVAL, errno);
ASSERT_EQ(-1,
landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr),
invalid_flag));
ASSERT_EQ(EINVAL, errno);
/* Checks too big ruleset_attr size. */
ASSERT_EQ(-1, landlock_create_ruleset(&ruleset_attr, -1, 0));
ASSERT_EQ(E2BIG, errno);
/* Checks too small ruleset_attr size. */
ASSERT_EQ(-1, landlock_create_ruleset(&ruleset_attr, 0, 0));
ASSERT_EQ(EINVAL, errno);
ASSERT_EQ(-1, landlock_create_ruleset(&ruleset_attr, 1, 0));
ASSERT_EQ(EINVAL, errno);
/* Checks valid call. */
ruleset_fd =
landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
ASSERT_LE(0, ruleset_fd);
ASSERT_EQ(0, close(ruleset_fd));
}
/* Tests ordering of syscall argument checks. */
TEST(add_rule_checks_ordering)
{
const struct landlock_ruleset_attr ruleset_attr = {
.handled_access_fs = LANDLOCK_ACCESS_FS_EXECUTE,
};
struct landlock_path_beneath_attr path_beneath_attr = {
.allowed_access = LANDLOCK_ACCESS_FS_EXECUTE,
.parent_fd = -1,
};
const int ruleset_fd =
landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
ASSERT_LE(0, ruleset_fd);
/* Checks invalid flags. */
ASSERT_EQ(-1, landlock_add_rule(-1, 0, NULL, 1));
ASSERT_EQ(EINVAL, errno);
/* Checks invalid ruleset FD. */
ASSERT_EQ(-1, landlock_add_rule(-1, 0, NULL, 0));
ASSERT_EQ(EBADF, errno);
/* Checks invalid rule type. */
ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, 0, NULL, 0));
ASSERT_EQ(EINVAL, errno);
/* Checks invalid rule attr. */
ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
NULL, 0));
ASSERT_EQ(EFAULT, errno);
/* Checks invalid path_beneath.parent_fd. */
ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
&path_beneath_attr, 0));
ASSERT_EQ(EBADF, errno);
/* Checks valid call. */
path_beneath_attr.parent_fd =
open("/tmp", O_PATH | O_NOFOLLOW | O_DIRECTORY | O_CLOEXEC);
ASSERT_LE(0, path_beneath_attr.parent_fd);
ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
&path_beneath_attr, 0));
ASSERT_EQ(0, close(path_beneath_attr.parent_fd));
ASSERT_EQ(0, close(ruleset_fd));
}
/* Tests ordering of syscall argument and permission checks. */
TEST(restrict_self_checks_ordering)
{
const struct landlock_ruleset_attr ruleset_attr = {
.handled_access_fs = LANDLOCK_ACCESS_FS_EXECUTE,
};
struct landlock_path_beneath_attr path_beneath_attr = {
.allowed_access = LANDLOCK_ACCESS_FS_EXECUTE,
.parent_fd = -1,
};
const int ruleset_fd =
landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
ASSERT_LE(0, ruleset_fd);
path_beneath_attr.parent_fd =
open("/tmp", O_PATH | O_NOFOLLOW | O_DIRECTORY | O_CLOEXEC);
ASSERT_LE(0, path_beneath_attr.parent_fd);
ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
&path_beneath_attr, 0));
ASSERT_EQ(0, close(path_beneath_attr.parent_fd));
/* Checks unprivileged enforcement without no_new_privs. */
drop_caps(_metadata);
ASSERT_EQ(-1, landlock_restrict_self(-1, -1));
ASSERT_EQ(EPERM, errno);
ASSERT_EQ(-1, landlock_restrict_self(-1, 0));
ASSERT_EQ(EPERM, errno);
ASSERT_EQ(-1, landlock_restrict_self(ruleset_fd, 0));
ASSERT_EQ(EPERM, errno);
ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0));
/* Checks invalid flags. */
ASSERT_EQ(-1, landlock_restrict_self(-1, -1));
ASSERT_EQ(EINVAL, errno);
/* Checks invalid ruleset FD. */
ASSERT_EQ(-1, landlock_restrict_self(-1, 0));
ASSERT_EQ(EBADF, errno);
/* Checks valid call. */
ASSERT_EQ(0, landlock_restrict_self(ruleset_fd, 0));
ASSERT_EQ(0, close(ruleset_fd));
}
TEST(ruleset_fd_io)
{
struct landlock_ruleset_attr ruleset_attr = {
.handled_access_fs = LANDLOCK_ACCESS_FS_READ_FILE,
};
int ruleset_fd;
char buf;
drop_caps(_metadata);
ruleset_fd =
landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
ASSERT_LE(0, ruleset_fd);
ASSERT_EQ(-1, write(ruleset_fd, ".", 1));
ASSERT_EQ(EINVAL, errno);
ASSERT_EQ(-1, read(ruleset_fd, &buf, 1));
ASSERT_EQ(EINVAL, errno);
ASSERT_EQ(0, close(ruleset_fd));
}
/* Tests enforcement of a ruleset FD transferred through a UNIX socket. */
TEST(ruleset_fd_transfer)
{
struct landlock_ruleset_attr ruleset_attr = {
.handled_access_fs = LANDLOCK_ACCESS_FS_READ_DIR,
};
struct landlock_path_beneath_attr path_beneath_attr = {
.allowed_access = LANDLOCK_ACCESS_FS_READ_DIR,
};
int ruleset_fd_tx, dir_fd;
int socket_fds[2];
pid_t child;
int status;
drop_caps(_metadata);
/* Creates a test ruleset with a simple rule. */
ruleset_fd_tx =
landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
ASSERT_LE(0, ruleset_fd_tx);
path_beneath_attr.parent_fd =
open("/tmp", O_PATH | O_NOFOLLOW | O_DIRECTORY | O_CLOEXEC);
ASSERT_LE(0, path_beneath_attr.parent_fd);
ASSERT_EQ(0,
landlock_add_rule(ruleset_fd_tx, LANDLOCK_RULE_PATH_BENEATH,
&path_beneath_attr, 0));
ASSERT_EQ(0, close(path_beneath_attr.parent_fd));
/* Sends the ruleset FD over a socketpair and then close it. */
ASSERT_EQ(0, socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0,
socket_fds));
ASSERT_EQ(0, send_fd(socket_fds[0], ruleset_fd_tx));
ASSERT_EQ(0, close(socket_fds[0]));
ASSERT_EQ(0, close(ruleset_fd_tx));
child = fork();
ASSERT_LE(0, child);
if (child == 0) {
const int ruleset_fd_rx = recv_fd(socket_fds[1]);
ASSERT_LE(0, ruleset_fd_rx);
ASSERT_EQ(0, close(socket_fds[1]));
/* Enforces the received ruleset on the child. */
ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0));
ASSERT_EQ(0, landlock_restrict_self(ruleset_fd_rx, 0));
ASSERT_EQ(0, close(ruleset_fd_rx));
/* Checks that the ruleset enforcement. */
ASSERT_EQ(-1, open("/", O_RDONLY | O_DIRECTORY | O_CLOEXEC));
ASSERT_EQ(EACCES, errno);
dir_fd = open("/tmp", O_RDONLY | O_DIRECTORY | O_CLOEXEC);
ASSERT_LE(0, dir_fd);
ASSERT_EQ(0, close(dir_fd));
_exit(_metadata->passed ? EXIT_SUCCESS : EXIT_FAILURE);
return;
}
ASSERT_EQ(0, close(socket_fds[1]));
/* Checks that the parent is unrestricted. */
dir_fd = open("/", O_RDONLY | O_DIRECTORY | O_CLOEXEC);
ASSERT_LE(0, dir_fd);
ASSERT_EQ(0, close(dir_fd));
dir_fd = open("/tmp", O_RDONLY | O_DIRECTORY | O_CLOEXEC);
ASSERT_LE(0, dir_fd);
ASSERT_EQ(0, close(dir_fd));
ASSERT_EQ(child, waitpid(child, &status, 0));
ASSERT_EQ(1, WIFEXITED(status));
ASSERT_EQ(EXIT_SUCCESS, WEXITSTATUS(status));
}
TEST_HARNESS_MAIN