io/tst-lstat-nofollow.c

   1 /* Test that lstat does not follow symbolic links.
   2    Copyright (C) 2024-2025 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <string.h>
  20 #include <support/check.h>
  21 #include <support/fuse.h>
  22 #include <support/support.h>
  23 #include <sys/stat.h>
  24 #include <unistd.h>
  25
  26 static void
  27 fuse_thread (struct support_fuse *f, void *closure)
  28 {
  29   struct fuse_in_header *inh;
  30   while ((inh = support_fuse_next (f)) != NULL)
  31     {
  32       if (support_fuse_handle_mountpoint (f)
  33           || (inh->nodeid == 1 && support_fuse_handle_directory (f)))
  34         continue;
  35       switch (inh->opcode)
  36         {
  37         case FUSE_LOOKUP:
  38           {
  39             TEST_COMPARE (inh->nodeid, 1);
  40             TEST_COMPARE_STRING (support_fuse_cast (LOOKUP, inh), "symlink");
  41             struct fuse_entry_out *out = support_fuse_prepare_entry (f, 2);
  42             out->attr.mode = S_IFLNK | 0777;
  43             out->attr.size = strlen ("target");
  44             support_fuse_reply_prepared (f);
  45           }
  46           break;
  47         case FUSE_GETATTR:
  48           {
  49             TEST_COMPARE (inh->nodeid, 2);
  50             struct fuse_attr_out *out = support_fuse_prepare_attr (f);
  51             out->attr.mode = S_IFLNK | 0777;
  52             out->attr.size = strlen ("target");
  53             support_fuse_reply_prepared (f);
  54           }
  55           break;
  56         case FUSE_READLINK:
  57           /* The lstat operation must not attempt to look at the
  58              symbolic link target.  */
  59           FAIL ("attempt to obtain target of symblic link for node %llu",
  60                 (unsigned long long int) inh->nodeid);
  61           break;
  62         default:
  63           FAIL ("unexpected event %s", support_fuse_opcode (inh->opcode));
  64         }
  65     }
  66 }
  67
  68 static int
  69 do_test (void)
  70 {
  71   support_fuse_init ();
  72   struct support_fuse *f = support_fuse_mount (fuse_thread, NULL);
  73   char *symlink_path = xasprintf ("%s/symlink", support_fuse_mountpoint (f));
  74
  75   {
  76     struct stat st = { 0, };
  77     TEST_COMPARE (lstat (symlink_path, &st), 0);
  78     TEST_COMPARE (st.st_uid, getuid ());
  79     TEST_COMPARE (st.st_gid, getgid ());
  80     TEST_COMPARE (st.st_size, 6);
  81     TEST_COMPARE (st.st_mode, S_IFLNK | 0777);
  82   }
  83
  84   {
  85     struct stat64 st = { 0, };
  86     TEST_COMPARE (lstat64 (symlink_path, &st), 0);
  87     TEST_COMPARE (st.st_uid, getuid ());
  88     TEST_COMPARE (st.st_gid, getgid ());
  89     TEST_COMPARE (st.st_size, 6);
  90     TEST_COMPARE (st.st_mode, S_IFLNK | 0777);
  91   }
  92
  93   free (symlink_path);
  94   support_fuse_unmount (f);
  95   return 0;
  96 }
  97
  98 #include <support/test-driver.c>