selftests: add clone3() CAP_CHECKPOINT_RESTORE test (1d27a0be) · Commits · 戴 / test

tools/testing/selftests/clone3/.gitignore

+1 −0

Original line number	Diff line number	Diff line
		@@ -2,3 +2,4 @@
		clone3
		clone3_clear_sighand
		clone3_set_tid
		clone3_cap_checkpoint_restore

tools/testing/selftests/clone3/Makefile

+3 −1

Original line number	Diff line number	Diff line
		# SPDX-License-Identifier: GPL-2.0
		CFLAGS += -g -I../../../../usr/include/
		LDLIBS += -lcap

		TEST_GEN_PROGS := clone3 clone3_clear_sighand clone3_set_tid
		TEST_GEN_PROGS := clone3 clone3_clear_sighand clone3_set_tid \
		clone3_cap_checkpoint_restore

		include ../lib.mk

tools/testing/selftests/clone3/clone3_cap_checkpoint_restore.c

0 → 100644

+182 −0

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0

		/*
		* Based on Christian Brauner's clone3() example.
		* These tests are assuming to be running in the host's
		* PID namespace.
		*/

		/* capabilities related code based on selftests/bpf/test_verifier.c */

		#define _GNU_SOURCE
		#include <errno.h>
		#include <linux/types.h>
		#include <linux/sched.h>
		#include <stdio.h>
		#include <stdlib.h>
		#include <stdbool.h>
		#include <sys/capability.h>
		#include <sys/prctl.h>
		#include <sys/syscall.h>
		#include <sys/types.h>
		#include <sys/un.h>
		#include <sys/wait.h>
		#include <unistd.h>
		#include <sched.h>

		#include "../kselftest_harness.h"
		#include "clone3_selftests.h"

		#ifndef MAX_PID_NS_LEVEL
		#define MAX_PID_NS_LEVEL 32
		#endif

		static void child_exit(int ret)
		{
		fflush(stdout);
		fflush(stderr);
		_exit(ret);
		}

		static int call_clone3_set_tid(struct __test_metadata *_metadata,
		pid_t *set_tid, size_t set_tid_size)
		{
		int status;
		pid_t pid = -1;

		struct clone_args args = {
		.exit_signal = SIGCHLD,
		.set_tid = ptr_to_u64(set_tid),
		.set_tid_size = set_tid_size,
		};

		pid = sys_clone3(&args, sizeof(struct clone_args));
		if (pid < 0) {
		TH_LOG("%s - Failed to create new process", strerror(errno));
		return -errno;
		}

		if (pid == 0) {
		int ret;
		char tmp = 0;

		TH_LOG("I am the child, my PID is %d (expected %d)", getpid(), set_tid[0]);

		if (set_tid[0] != getpid())
		child_exit(EXIT_FAILURE);
		child_exit(EXIT_SUCCESS);
		}

		TH_LOG("I am the parent (%d). My child's pid is %d", getpid(), pid);

		if (waitpid(pid, &status, 0) < 0) {
		TH_LOG("Child returned %s", strerror(errno));
		return -errno;
		}

		if (!WIFEXITED(status))
		return -1;

		return WEXITSTATUS(status);
		}

		static int test_clone3_set_tid(struct __test_metadata *_metadata,
		pid_t *set_tid, size_t set_tid_size)
		{
		int ret;

		TH_LOG("[%d] Trying clone3() with CLONE_SET_TID to %d", getpid(), set_tid[0]);
		ret = call_clone3_set_tid(_metadata, set_tid, set_tid_size);
		TH_LOG("[%d] clone3() with CLONE_SET_TID %d says:%d", getpid(), set_tid[0], ret);
		return ret;
		}

		struct libcap {
		struct __user_cap_header_struct hdr;
		struct __user_cap_data_struct data[2];
		};

		static int set_capability(void)
		{
		cap_value_t cap_values[] = { CAP_SETUID, CAP_SETGID };
		struct libcap *cap;
		int ret = -1;
		cap_t caps;

		caps = cap_get_proc();
		if (!caps) {
		perror("cap_get_proc");
		return -1;
		}

		/* Drop all capabilities */
		if (cap_clear(caps)) {
		perror("cap_clear");
		goto out;
		}

		cap_set_flag(caps, CAP_EFFECTIVE, 2, cap_values, CAP_SET);
		cap_set_flag(caps, CAP_PERMITTED, 2, cap_values, CAP_SET);

		cap = (struct libcap *) caps;

		/* 40 -> CAP_CHECKPOINT_RESTORE */
		cap->data[1].effective \|= 1 << (40 - 32);
		cap->data[1].permitted \|= 1 << (40 - 32);

		if (cap_set_proc(caps)) {
		perror("cap_set_proc");
		goto out;
		}
		ret = 0;
		out:
		if (cap_free(caps))
		perror("cap_free");
		return ret;
		}

		TEST(clone3_cap_checkpoint_restore)
		{
		pid_t pid;
		int status;
		int ret = 0;
		pid_t set_tid[1];

		test_clone3_supported();

		EXPECT_EQ(getuid(), 0)
		XFAIL(return, "Skipping all tests as non-root\n");

		memset(&set_tid, 0, sizeof(set_tid));

		/* Find the current active PID */
		pid = fork();
		if (pid == 0) {
		TH_LOG("Child has PID %d", getpid());
		child_exit(EXIT_SUCCESS);
		}
		ASSERT_GT(waitpid(pid, &status, 0), 0)
		TH_LOG("Waiting for child %d failed", pid);

		/* After the child has finished, its PID should be free. */
		set_tid[0] = pid;

		ASSERT_EQ(set_capability(), 0)
		TH_LOG("Could not set CAP_CHECKPOINT_RESTORE");

		ASSERT_EQ(prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0), 0);

		EXPECT_EQ(setgid(65534), 0)
		TH_LOG("Failed to setgid(65534)");
		ASSERT_EQ(setuid(65534), 0);

		set_tid[0] = pid;
		/* This would fail without CAP_CHECKPOINT_RESTORE */
		ASSERT_EQ(test_clone3_set_tid(_metadata, set_tid, 1), -EPERM);
		ASSERT_EQ(set_capability(), 0)
		TH_LOG("Could not set CAP_CHECKPOINT_RESTORE");
		/* This should work as we have CAP_CHECKPOINT_RESTORE as non-root */
		ASSERT_EQ(test_clone3_set_tid(_metadata, set_tid, 1), 0);
		}

		TEST_HARNESS_MAIN

Admin message