cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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clone3_cap_checkpoint_restore.c (4000B)

      1// SPDX-License-Identifier: GPL-2.0
      2
      3/*
      4 * Based on Christian Brauner's clone3() example.
      5 * These tests are assuming to be running in the host's
      6 * PID namespace.
      7 */
      8
      9/* capabilities related code based on selftests/bpf/test_verifier.c */
     10
     11#define _GNU_SOURCE
     12#include <errno.h>
     13#include <linux/types.h>
     14#include <linux/sched.h>
     15#include <stdio.h>
     16#include <stdlib.h>
     17#include <stdbool.h>
     18#include <sys/capability.h>
     19#include <sys/prctl.h>
     20#include <sys/syscall.h>
     21#include <sys/types.h>
     22#include <sys/un.h>
     23#include <sys/wait.h>
     24#include <unistd.h>
     25#include <sched.h>
     26
     27#include "../kselftest_harness.h"
     28#include "clone3_selftests.h"
     29
     30#ifndef MAX_PID_NS_LEVEL
     31#define MAX_PID_NS_LEVEL 32
     32#endif
     33
     34static void child_exit(int ret)
     35{
     36	fflush(stdout);
     37	fflush(stderr);
     38	_exit(ret);
     39}
     40
     41static int call_clone3_set_tid(struct __test_metadata *_metadata,
     42			       pid_t *set_tid, size_t set_tid_size)
     43{
     44	int status;
     45	pid_t pid = -1;
     46
     47	struct __clone_args args = {
     48		.exit_signal = SIGCHLD,
     49		.set_tid = ptr_to_u64(set_tid),
     50		.set_tid_size = set_tid_size,
     51	};
     52
     53	pid = sys_clone3(&args, sizeof(args));
     54	if (pid < 0) {
     55		TH_LOG("%s - Failed to create new process", strerror(errno));
     56		return -errno;
     57	}
     58
     59	if (pid == 0) {
     60		int ret;
     61		char tmp = 0;
     62
     63		TH_LOG("I am the child, my PID is %d (expected %d)", getpid(), set_tid[0]);
     64
     65		if (set_tid[0] != getpid())
     66			child_exit(EXIT_FAILURE);
     67		child_exit(EXIT_SUCCESS);
     68	}
     69
     70	TH_LOG("I am the parent (%d). My child's pid is %d", getpid(), pid);
     71
     72	if (waitpid(pid, &status, 0) < 0) {
     73		TH_LOG("Child returned %s", strerror(errno));
     74		return -errno;
     75	}
     76
     77	if (!WIFEXITED(status))
     78		return -1;
     79
     80	return WEXITSTATUS(status);
     81}
     82
     83static int test_clone3_set_tid(struct __test_metadata *_metadata,
     84			       pid_t *set_tid, size_t set_tid_size)
     85{
     86	int ret;
     87
     88	TH_LOG("[%d] Trying clone3() with CLONE_SET_TID to %d", getpid(), set_tid[0]);
     89	ret = call_clone3_set_tid(_metadata, set_tid, set_tid_size);
     90	TH_LOG("[%d] clone3() with CLONE_SET_TID %d says:%d", getpid(), set_tid[0], ret);
     91	return ret;
     92}
     93
     94struct libcap {
     95	struct __user_cap_header_struct hdr;
     96	struct __user_cap_data_struct data[2];
     97};
     98
     99static int set_capability(void)
    100{
    101	cap_value_t cap_values[] = { CAP_SETUID, CAP_SETGID };
    102	struct libcap *cap;
    103	int ret = -1;
    104	cap_t caps;
    105
    106	caps = cap_get_proc();
    107	if (!caps) {
    108		perror("cap_get_proc");
    109		return -1;
    110	}
    111
    112	/* Drop all capabilities */
    113	if (cap_clear(caps)) {
    114		perror("cap_clear");
    115		goto out;
    116	}
    117
    118	cap_set_flag(caps, CAP_EFFECTIVE, 2, cap_values, CAP_SET);
    119	cap_set_flag(caps, CAP_PERMITTED, 2, cap_values, CAP_SET);
    120
    121	cap = (struct libcap *) caps;
    122
    123	/* 40 -> CAP_CHECKPOINT_RESTORE */
    124	cap->data[1].effective |= 1 << (40 - 32);
    125	cap->data[1].permitted |= 1 << (40 - 32);
    126
    127	if (cap_set_proc(caps)) {
    128		perror("cap_set_proc");
    129		goto out;
    130	}
    131	ret = 0;
    132out:
    133	if (cap_free(caps))
    134		perror("cap_free");
    135	return ret;
    136}
    137
    138TEST(clone3_cap_checkpoint_restore)
    139{
    140	pid_t pid;
    141	int status;
    142	int ret = 0;
    143	pid_t set_tid[1];
    144
    145	test_clone3_supported();
    146
    147	EXPECT_EQ(getuid(), 0)
    148		SKIP(return, "Skipping all tests as non-root");
    149
    150	memset(&set_tid, 0, sizeof(set_tid));
    151
    152	/* Find the current active PID */
    153	pid = fork();
    154	if (pid == 0) {
    155		TH_LOG("Child has PID %d", getpid());
    156		child_exit(EXIT_SUCCESS);
    157	}
    158	ASSERT_GT(waitpid(pid, &status, 0), 0)
    159		TH_LOG("Waiting for child %d failed", pid);
    160
    161	/* After the child has finished, its PID should be free. */
    162	set_tid[0] = pid;
    163
    164	ASSERT_EQ(set_capability(), 0)
    165		TH_LOG("Could not set CAP_CHECKPOINT_RESTORE");
    166
    167	ASSERT_EQ(prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0), 0);
    168
    169	EXPECT_EQ(setgid(65534), 0)
    170		TH_LOG("Failed to setgid(65534)");
    171	ASSERT_EQ(setuid(65534), 0);
    172
    173	set_tid[0] = pid;
    174	/* This would fail without CAP_CHECKPOINT_RESTORE */
    175	ASSERT_EQ(test_clone3_set_tid(_metadata, set_tid, 1), -EPERM);
    176	ASSERT_EQ(set_capability(), 0)
    177		TH_LOG("Could not set CAP_CHECKPOINT_RESTORE");
    178	/* This should work as we have CAP_CHECKPOINT_RESTORE as non-root */
    179	ASSERT_EQ(test_clone3_set_tid(_metadata, set_tid, 1), 0);
    180}
    181
    182TEST_HARNESS_MAIN