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