tools/testing/selftests/bpf/prog_tests/d_path.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #define _GNU_SOURCE
   3 #include <test_progs.h>
   4 #include <sys/stat.h>
   5 #include <linux/sched.h>
   6 #include <sys/syscall.h>
   7
   8 #define MAX_PATH_LEN            128
   9 #define MAX_FILES               7
  10
  11 #include "test_d_path.skel.h"
  12
  13 static int duration;
  14
  15 static struct {
  16         __u32 cnt;
  17         char paths[MAX_FILES][MAX_PATH_LEN];
  18 } src;
  19
  20 static int set_pathname(int fd, pid_t pid)
  21 {
  22         char buf[MAX_PATH_LEN];
  23
  24         snprintf(buf, MAX_PATH_LEN, "/proc/%d/fd/%d", pid, fd);
  25         return readlink(buf, src.paths[src.cnt++], MAX_PATH_LEN);
  26 }
  27
  28 static int trigger_fstat_events(pid_t pid)
  29 {
  30         int sockfd = -1, procfd = -1, devfd = -1;
  31         int localfd = -1, indicatorfd = -1;
  32         int pipefd[2] = { -1, -1 };
  33         struct stat fileStat;
  34         int ret = -1;
  35
  36         /* unmountable pseudo-filesystems */
  37         if (CHECK(pipe(pipefd) < 0, "trigger", "pipe failed\n"))
  38                 return ret;
  39         /* unmountable pseudo-filesystems */
  40         sockfd = socket(AF_INET, SOCK_STREAM, 0);
  41         if (CHECK(sockfd < 0, "trigger", "socket failed\n"))
  42                 goto out_close;
  43         /* mountable pseudo-filesystems */
  44         procfd = open("/proc/self/comm", O_RDONLY);
  45         if (CHECK(procfd < 0, "trigger", "open /proc/self/comm failed\n"))
  46                 goto out_close;
  47         devfd = open("/dev/urandom", O_RDONLY);
  48         if (CHECK(devfd < 0, "trigger", "open /dev/urandom failed\n"))
  49                 goto out_close;
  50         localfd = open("/tmp/d_path_loadgen.txt", O_CREAT | O_RDONLY, 0644);
  51         if (CHECK(localfd < 0, "trigger", "open /tmp/d_path_loadgen.txt failed\n"))
  52                 goto out_close;
  53         /* bpf_d_path will return path with (deleted) */
  54         remove("/tmp/d_path_loadgen.txt");
  55         indicatorfd = open("/tmp/", O_PATH);
  56         if (CHECK(indicatorfd < 0, "trigger", "open /tmp/ failed\n"))
  57                 goto out_close;
  58
  59         ret = set_pathname(pipefd[0], pid);
  60         if (CHECK(ret < 0, "trigger", "set_pathname failed for pipe[0]\n"))
  61                 goto out_close;
  62         ret = set_pathname(pipefd[1], pid);
  63         if (CHECK(ret < 0, "trigger", "set_pathname failed for pipe[1]\n"))
  64                 goto out_close;
  65         ret = set_pathname(sockfd, pid);
  66         if (CHECK(ret < 0, "trigger", "set_pathname failed for socket\n"))
  67                 goto out_close;
  68         ret = set_pathname(procfd, pid);
  69         if (CHECK(ret < 0, "trigger", "set_pathname failed for proc\n"))
  70                 goto out_close;
  71         ret = set_pathname(devfd, pid);
  72         if (CHECK(ret < 0, "trigger", "set_pathname failed for dev\n"))
  73                 goto out_close;
  74         ret = set_pathname(localfd, pid);
  75         if (CHECK(ret < 0, "trigger", "set_pathname failed for file\n"))
  76                 goto out_close;
  77         ret = set_pathname(indicatorfd, pid);
  78         if (CHECK(ret < 0, "trigger", "set_pathname failed for dir\n"))
  79                 goto out_close;
  80
  81         /* triggers vfs_getattr */
  82         fstat(pipefd[0], &fileStat);
  83         fstat(pipefd[1], &fileStat);
  84         fstat(sockfd, &fileStat);
  85         fstat(procfd, &fileStat);
  86         fstat(devfd, &fileStat);
  87         fstat(localfd, &fileStat);
  88         fstat(indicatorfd, &fileStat);
  89
  90 out_close:
  91         /* triggers filp_close */
  92         close(pipefd[0]);
  93         close(pipefd[1]);
  94         close(sockfd);
  95         close(procfd);
  96         close(devfd);
  97         close(localfd);
  98         close(indicatorfd);
  99         return ret;
 100 }
 101
 102 void test_d_path(void)
 103 {
 104         struct test_d_path__bss *bss;
 105         struct test_d_path *skel;
 106         int err;
 107
 108         skel = test_d_path__open_and_load();
 109         if (CHECK(!skel, "setup", "d_path skeleton failed\n"))
 110                 goto cleanup;
 111
 112         err = test_d_path__attach(skel);
 113         if (CHECK(err, "setup", "attach failed: %d\n", err))
 114                 goto cleanup;
 115
 116         bss = skel->bss;
 117         bss->my_pid = getpid();
 118
 119         err = trigger_fstat_events(bss->my_pid);
 120         if (err < 0)
 121                 goto cleanup;
 122
 123         if (CHECK(!bss->called_stat,
 124                   "stat",
 125                   "trampoline for security_inode_getattr was not called\n"))
 126                 goto cleanup;
 127
 128         if (CHECK(!bss->called_close,
 129                   "close",
 130                   "trampoline for filp_close was not called\n"))
 131                 goto cleanup;
 132
 133         for (int i = 0; i < MAX_FILES; i++) {
 134                 CHECK(strncmp(src.paths[i], bss->paths_stat[i], MAX_PATH_LEN),
 135                       "check",
 136                       "failed to get stat path[%d]: %s vs %s\n",
 137                       i, src.paths[i], bss->paths_stat[i]);
 138                 CHECK(strncmp(src.paths[i], bss->paths_close[i], MAX_PATH_LEN),
 139                       "check",
 140                       "failed to get close path[%d]: %s vs %s\n",
 141                       i, src.paths[i], bss->paths_close[i]);
 142                 /* The d_path helper returns size plus NUL char, hence + 1 */
 143                 CHECK(bss->rets_stat[i] != strlen(bss->paths_stat[i]) + 1,
 144                       "check",
 145                       "failed to match stat return [%d]: %d vs %zd [%s]\n",
 146                       i, bss->rets_stat[i], strlen(bss->paths_stat[i]) + 1,
 147                       bss->paths_stat[i]);
 148                 CHECK(bss->rets_close[i] != strlen(bss->paths_stat[i]) + 1,
 149                       "check",
 150                       "failed to match stat return [%d]: %d vs %zd [%s]\n",
 151                       i, bss->rets_close[i], strlen(bss->paths_close[i]) + 1,
 152                       bss->paths_stat[i]);
 153         }
 154
 155 cleanup:
 156         test_d_path__destroy(skel);
 157 }