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// SPDX-License-Identifier: GPL-2.0
/*
* Landlock tests - Signal Scoping
*
* Copyright © 2024 Tahera Fahimi <fahimitahera@gmail.com>
*/
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <linux/landlock.h>
#include <signal.h>
#include <sys/prctl.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include "common.h"
#include "scoped_common.h"
/* This variable is used for handling several signals. */
static volatile sig_atomic_t is_signaled;
/* clang-format off */
FIXTURE(scoping_signals) {};
/* clang-format on */
FIXTURE_VARIANT(scoping_signals)
{
int sig;
};
/* clang-format off */
FIXTURE_VARIANT_ADD(scoping_signals, sigtrap) {
/* clang-format on */
.sig = SIGTRAP,
};
/* clang-format off */
FIXTURE_VARIANT_ADD(scoping_signals, sigurg) {
/* clang-format on */
.sig = SIGURG,
};
/* clang-format off */
FIXTURE_VARIANT_ADD(scoping_signals, sighup) {
/* clang-format on */
.sig = SIGHUP,
};
/* clang-format off */
FIXTURE_VARIANT_ADD(scoping_signals, sigtstp) {
/* clang-format on */
.sig = SIGTSTP,
};
FIXTURE_SETUP(scoping_signals)
{
drop_caps(_metadata);
is_signaled = 0;
}
FIXTURE_TEARDOWN(scoping_signals)
{
}
static void scope_signal_handler(int sig, siginfo_t *info, void *ucontext)
{
if (sig == SIGTRAP || sig == SIGURG || sig == SIGHUP || sig == SIGTSTP)
is_signaled = 1;
}
/*
* In this test, a child process sends a signal to parent before and
* after getting scoped.
*/
TEST_F(scoping_signals, send_sig_to_parent)
{
int pipe_parent[2];
int status;
pid_t child;
pid_t parent = getpid();
struct sigaction action = {
.sa_sigaction = scope_signal_handler,
.sa_flags = SA_SIGINFO,
};
ASSERT_EQ(0, pipe2(pipe_parent, O_CLOEXEC));
ASSERT_LE(0, sigaction(variant->sig, &action, NULL));
/* The process should not have already been signaled. */
EXPECT_EQ(0, is_signaled);
child = fork();
ASSERT_LE(0, child);
if (child == 0) {
char buf_child;
int err;
EXPECT_EQ(0, close(pipe_parent[1]));
/*
* The child process can send signal to parent when
* domain is not scoped.
*/
err = kill(parent, variant->sig);
ASSERT_EQ(0, err);
ASSERT_EQ(1, read(pipe_parent[0], &buf_child, 1));
EXPECT_EQ(0, close(pipe_parent[0]));
create_scoped_domain(_metadata, LANDLOCK_SCOPE_SIGNAL);
/*
* The child process cannot send signal to the parent
* anymore.
*/
err = kill(parent, variant->sig);
ASSERT_EQ(-1, err);
ASSERT_EQ(EPERM, errno);
/*
* No matter of the domain, a process should be able to
* send a signal to itself.
*/
ASSERT_EQ(0, is_signaled);
ASSERT_EQ(0, raise(variant->sig));
ASSERT_EQ(1, is_signaled);
_exit(_metadata->exit_code);
return;
}
EXPECT_EQ(0, close(pipe_parent[0]));
/* Waits for a first signal to be received, without race condition. */
while (!is_signaled && !usleep(1))
;
ASSERT_EQ(1, is_signaled);
ASSERT_EQ(1, write(pipe_parent[1], ".", 1));
EXPECT_EQ(0, close(pipe_parent[1]));
is_signaled = 0;
ASSERT_EQ(child, waitpid(child, &status, 0));
if (WIFSIGNALED(status) || !WIFEXITED(status) ||
WEXITSTATUS(status) != EXIT_SUCCESS)
_metadata->exit_code = KSFT_FAIL;
EXPECT_EQ(0, is_signaled);
}
/* clang-format off */
FIXTURE(scoped_domains) {};
/* clang-format on */
#include "scoped_base_variants.h"
FIXTURE_SETUP(scoped_domains)
{
drop_caps(_metadata);
}
FIXTURE_TEARDOWN(scoped_domains)
{
}
/*
* This test ensures that a scoped process cannot send signal out of
* scoped domain.
*/
TEST_F(scoped_domains, check_access_signal)
{
pid_t child;
pid_t parent = getpid();
int status;
bool can_signal_child, can_signal_parent;
int pipe_parent[2], pipe_child[2];
char buf_parent;
int err;
can_signal_parent = !variant->domain_child;
can_signal_child = !variant->domain_parent;
if (variant->domain_both)
create_scoped_domain(_metadata, LANDLOCK_SCOPE_SIGNAL);
ASSERT_EQ(0, pipe2(pipe_parent, O_CLOEXEC));
ASSERT_EQ(0, pipe2(pipe_child, O_CLOEXEC));
child = fork();
ASSERT_LE(0, child);
if (child == 0) {
char buf_child;
EXPECT_EQ(0, close(pipe_child[0]));
EXPECT_EQ(0, close(pipe_parent[1]));
if (variant->domain_child)
create_scoped_domain(_metadata, LANDLOCK_SCOPE_SIGNAL);
ASSERT_EQ(1, write(pipe_child[1], ".", 1));
EXPECT_EQ(0, close(pipe_child[1]));
/* Waits for the parent to send signals. */
ASSERT_EQ(1, read(pipe_parent[0], &buf_child, 1));
EXPECT_EQ(0, close(pipe_parent[0]));
err = kill(parent, 0);
if (can_signal_parent) {
ASSERT_EQ(0, err);
} else {
ASSERT_EQ(-1, err);
ASSERT_EQ(EPERM, errno);
}
/*
* No matter of the domain, a process should be able to
* send a signal to itself.
*/
ASSERT_EQ(0, raise(0));
_exit(_metadata->exit_code);
return;
}
EXPECT_EQ(0, close(pipe_parent[0]));
EXPECT_EQ(0, close(pipe_child[1]));
if (variant->domain_parent)
create_scoped_domain(_metadata, LANDLOCK_SCOPE_SIGNAL);
ASSERT_EQ(1, read(pipe_child[0], &buf_parent, 1));
EXPECT_EQ(0, close(pipe_child[0]));
err = kill(child, 0);
if (can_signal_child) {
ASSERT_EQ(0, err);
} else {
ASSERT_EQ(-1, err);
ASSERT_EQ(EPERM, errno);
}
ASSERT_EQ(0, raise(0));
ASSERT_EQ(1, write(pipe_parent[1], ".", 1));
EXPECT_EQ(0, close(pipe_parent[1]));
ASSERT_EQ(child, waitpid(child, &status, 0));
if (WIFSIGNALED(status) || !WIFEXITED(status) ||
WEXITSTATUS(status) != EXIT_SUCCESS)
_metadata->exit_code = KSFT_FAIL;
}
TEST_HARNESS_MAIN
|
