elf/tst-env-setuid-tunables.c

   1 /* Copyright (C) 2017-2023 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 /* Verify that tunables correctly filter out unsafe tunables like
  19    glibc.malloc.check and glibc.malloc.mmap_threshold but also retain
  20    glibc.malloc.mmap_threshold in an unprivileged child.  */
  21
  22 #define _LIBC 1
  23 #include "config.h"
  24 #undef _LIBC
  25
  26 #include <errno.h>
  27 #include <fcntl.h>
  28 #include <stdlib.h>
  29 #include <stdint.h>
  30 #include <stdio.h>
  31 #include <string.h>
  32 #include <sys/stat.h>
  33 #include <sys/wait.h>
  34 #include <unistd.h>
  35 #include <intprops.h>
  36 #include <array_length.h>
  37
  38 #include <support/check.h>
  39 #include <support/support.h>
  40 #include <support/test-driver.h>
  41 #include <support/capture_subprocess.h>
  42
  43 const char *teststrings[] =
  44 {
  45   "glibc.malloc.check=2:glibc.malloc.mmap_threshold=4096",
  46   "glibc.malloc.check=2:glibc.malloc.check=2:glibc.malloc.mmap_threshold=4096",
  47   "glibc.malloc.check=2:glibc.malloc.mmap_threshold=4096:glibc.malloc.check=2",
  48   "glibc.malloc.perturb=0x800",
  49   "glibc.malloc.perturb=0x800:glibc.malloc.mmap_threshold=4096",
  50   "glibc.malloc.perturb=0x800:not_valid.malloc.check=2:glibc.malloc.mmap_threshold=4096",
  51   "glibc.not_valid.check=2:glibc.malloc.mmap_threshold=4096",
  52   "not_valid.malloc.check=2:glibc.malloc.mmap_threshold=4096",
  53   "glibc.malloc.mmap_threshold=glibc.malloc.mmap_threshold=4096",
  54   "glibc.malloc.check=2",
  55   "glibc.malloc.garbage=2:glibc.maoc.mmap_threshold=4096:glibc.malloc.check=2",
  56   "glibc.malloc.check=4:glibc.malloc.garbage=2:glibc.maoc.mmap_threshold=4096",
  57   ":glibc.malloc.garbage=2:glibc.malloc.check=1",
  58   "glibc.malloc.check=1:glibc.malloc.check=2",
  59   "not_valid.malloc.check=2",
  60   "glibc.not_valid.check=2",
  61 };
  62
  63 const char *resultstrings[] =
  64 {
  65   "glibc.malloc.mmap_threshold=4096",
  66   "glibc.malloc.mmap_threshold=4096",
  67   "glibc.malloc.mmap_threshold=4096",
  68   "glibc.malloc.perturb=0x800",
  69   "glibc.malloc.perturb=0x800:glibc.malloc.mmap_threshold=4096",
  70   "glibc.malloc.perturb=0x800:glibc.malloc.mmap_threshold=4096",
  71   "glibc.malloc.mmap_threshold=4096",
  72   "glibc.malloc.mmap_threshold=4096",
  73   "glibc.malloc.mmap_threshold=glibc.malloc.mmap_threshold=4096",
  74   "",
  75   "",
  76   "",
  77   "",
  78   "",
  79   "",
  80   "",
  81 };
  82
  83 static int
  84 test_child (int off)
  85 {
  86   const char *val = getenv ("GLIBC_TUNABLES");
  87
  88   printf ("    [%d] GLIBC_TUNABLES is %s\n", off, val);
  89   fflush (stdout);
  90   if (val != NULL && strcmp (val, resultstrings[off]) == 0)
  91     return 0;
  92
  93   if (val != NULL)
  94     printf ("    [%d] Unexpected GLIBC_TUNABLES VALUE %s, expected %s\n",
  95             off, val, resultstrings[off]);
  96   else
  97     printf ("    [%d] GLIBC_TUNABLES environment variable absent\n", off);
  98
  99   fflush (stdout);
 100
 101   return 1;
 102 }
 103
 104 static int
 105 do_test (int argc, char **argv)
 106 {
 107   /* Setgid child process.  */
 108   if (argc == 2)
 109     {
 110       if (getgid () == getegid ())
 111         /* This can happen if the file system is mounted nosuid.  */
 112         FAIL_UNSUPPORTED ("SGID failed: GID and EGID match (%jd)\n",
 113                           (intmax_t) getgid ());
 114
 115       int ret = test_child (atoi (argv[1]));
 116
 117       if (ret != 0)
 118         exit (1);
 119
 120       /* Special return code to make sure that the child executed all the way
 121          through.  */
 122       exit (42);
 123     }
 124   else
 125     {
 126       /* Spawn tests.  */
 127       for (int i = 0; i < array_length (teststrings); i++)
 128         {
 129           char buf[INT_BUFSIZE_BOUND (int)];
 130
 131           printf ("[%d] Spawned test for %s\n", i, teststrings[i]);
 132           snprintf (buf, sizeof (buf), "%d\n", i);
 133           fflush (stdout);
 134           if (setenv ("GLIBC_TUNABLES", teststrings[i], 1) != 0)
 135             {
 136               printf ("    [%d] Failed to set GLIBC_TUNABLES: %m", i);
 137               support_record_failure ();
 138               continue;
 139             }
 140
 141           int status = support_capture_subprogram_self_sgid (buf);
 142
 143           /* Bail out early if unsupported.  */
 144           if (WEXITSTATUS (status) == EXIT_UNSUPPORTED)
 145             return EXIT_UNSUPPORTED;
 146
 147           if (WEXITSTATUS (status) != 42)
 148             {
 149               printf ("    [%d] child failed with status %d\n", i,
 150                       WEXITSTATUS (status));
 151               support_record_failure ();
 152             }
 153         }
 154       return 0;
 155     }
 156 }
 157
 158 #define TEST_FUNCTION_ARGV do_test
 159 #include <support/test-driver.c>