tools/testing/selftests/bpf/test_current_pid_tgid_new_ns.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2020 Carlos Neira cneirabustos@gmail.com */
   3 #define _GNU_SOURCE
   4 #include <sys/stat.h>
   5 #include <sys/types.h>
   6 #include <unistd.h>
   7 #include <sys/syscall.h>
   8 #include <sched.h>
   9 #include <sys/wait.h>
  10 #include <sys/mount.h>
  11 #include "test_progs.h"
  12
  13 #define CHECK_NEWNS(condition, tag, format...) ({               \
  14         int __ret = !!(condition);                      \
  15         if (__ret) {                                    \
  16                 printf("%s:FAIL:%s ", __func__, tag);   \
  17                 printf(format);                         \
  18         } else {                                        \
  19                 printf("%s:PASS:%s\n", __func__, tag);  \
  20         }                                               \
  21         __ret;                                          \
  22 })
  23
  24 struct bss {
  25         __u64 dev;
  26         __u64 ino;
  27         __u64 pid_tgid;
  28         __u64 user_pid_tgid;
  29 };
  30
  31 int main(int argc, char **argv)
  32 {
  33         pid_t pid;
  34         int exit_code = 1;
  35         struct stat st;
  36
  37         printf("Testing bpf_get_ns_current_pid_tgid helper in new ns\n");
  38
  39         if (stat("/proc/self/ns/pid", &st)) {
  40                 perror("stat failed on /proc/self/ns/pid ns\n");
  41                 printf("%s:FAILED\n", argv[0]);
  42                 return exit_code;
  43         }
  44
  45         if (CHECK_NEWNS(unshare(CLONE_NEWPID | CLONE_NEWNS),
  46                         "unshare CLONE_NEWPID | CLONE_NEWNS", "error errno=%d\n", errno))
  47                 return exit_code;
  48
  49         pid = fork();
  50         if (pid == -1) {
  51                 perror("Fork() failed\n");
  52                 printf("%s:FAILED\n", argv[0]);
  53                 return exit_code;
  54         }
  55
  56         if (pid > 0) {
  57                 int status;
  58
  59                 usleep(5);
  60                 waitpid(pid, &status, 0);
  61                 return 0;
  62         } else {
  63
  64                 pid = fork();
  65                 if (pid == -1) {
  66                         perror("Fork() failed\n");
  67                         printf("%s:FAILED\n", argv[0]);
  68                         return exit_code;
  69                 }
  70
  71                 if (pid > 0) {
  72                         int status;
  73                         waitpid(pid, &status, 0);
  74                         return 0;
  75                 } else {
  76                         if (CHECK_NEWNS(mount("none", "/proc", NULL, MS_PRIVATE|MS_REC, NULL),
  77                                 "Unmounting proc", "Cannot umount proc! errno=%d\n", errno))
  78                                 return exit_code;
  79
  80                         if (CHECK_NEWNS(mount("proc", "/proc", "proc", MS_NOSUID|MS_NOEXEC|MS_NODEV, NULL),
  81                                 "Mounting proc", "Cannot mount proc! errno=%d\n", errno))
  82                                 return exit_code;
  83
  84                         const char *probe_name = "raw_tracepoint/sys_enter";
  85                         const char *file = "test_ns_current_pid_tgid.o";
  86                         struct bpf_link *link = NULL;
  87                         struct bpf_program *prog;
  88                         struct bpf_map *bss_map;
  89                         struct bpf_object *obj;
  90                         int exit_code = 1;
  91                         int err, key = 0;
  92                         struct bss bss;
  93                         struct stat st;
  94                         __u64 id;
  95
  96                         obj = bpf_object__open_file(file, NULL);
  97                         if (CHECK_NEWNS(IS_ERR(obj), "obj_open", "err %ld\n", PTR_ERR(obj)))
  98                                 return exit_code;
  99
 100                         err = bpf_object__load(obj);
 101                         if (CHECK_NEWNS(err, "obj_load", "err %d errno %d\n", err, errno))
 102                                 goto cleanup;
 103
 104                         bss_map = bpf_object__find_map_by_name(obj, "test_ns_.bss");
 105                         if (CHECK_NEWNS(!bss_map, "find_bss_map", "failed\n"))
 106                                 goto cleanup;
 107
 108                         prog = bpf_object__find_program_by_title(obj, probe_name);
 109                         if (CHECK_NEWNS(!prog, "find_prog", "prog '%s' not found\n",
 110                                                 probe_name))
 111                                 goto cleanup;
 112
 113                         memset(&bss, 0, sizeof(bss));
 114                         pid_t tid = syscall(SYS_gettid);
 115                         pid_t pid = getpid();
 116
 117                         id = (__u64) tid << 32 | pid;
 118                         bss.user_pid_tgid = id;
 119
 120                         if (CHECK_NEWNS(stat("/proc/self/ns/pid", &st),
 121                                 "stat new ns", "Failed to stat /proc/self/ns/pid errno=%d\n", errno))
 122                                 goto cleanup;
 123
 124                         bss.dev = st.st_dev;
 125                         bss.ino = st.st_ino;
 126
 127                         err = bpf_map_update_elem(bpf_map__fd(bss_map), &key, &bss, 0);
 128                         if (CHECK_NEWNS(err, "setting_bss", "failed to set bss : %d\n", err))
 129                                 goto cleanup;
 130
 131                         link = bpf_program__attach_raw_tracepoint(prog, "sys_enter");
 132                         if (CHECK_NEWNS(IS_ERR(link), "attach_raw_tp", "err %ld\n",
 133                                                 PTR_ERR(link))) {
 134                                 link = NULL;
 135                                 goto cleanup;
 136                         }
 137
 138                         /* trigger some syscalls */
 139                         usleep(1);
 140
 141                         err = bpf_map_lookup_elem(bpf_map__fd(bss_map), &key, &bss);
 142                         if (CHECK_NEWNS(err, "set_bss", "failed to get bss : %d\n", err))
 143                                 goto cleanup;
 144
 145                         if (CHECK_NEWNS(id != bss.pid_tgid, "Compare user pid/tgid vs. bpf pid/tgid",
 146                                                 "User pid/tgid %llu BPF pid/tgid %llu\n", id, bss.pid_tgid))
 147                                 goto cleanup;
 148
 149                         exit_code = 0;
 150                         printf("%s:PASS\n", argv[0]);
 151 cleanup:
 152                         if (!link) {
 153                                 bpf_link__destroy(link);
 154                                 link = NULL;
 155                         }
 156                         bpf_object__close(obj);
 157                 }
 158         }
 159 }