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Re: [PATCH] elf: Add tst-ldconfig-bad-aux-cache test [BZ #18093]


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On Mon, Apr 15, 2019 at 8:18 PM Alexandra Hájková
<alexandra.khirnova@gmail.com> wrote:
>
> From: Alexandra Hájková <ahajkova@redhat.com>
>
>       This test corrupts /var/cache/ldconfig/aux-cache and executes ldconfig
>       to check it will not segfault using the corrupted aux_cache. The test
>       uses the test-in-container framework. Verified no regressions on
>       x86_64.
>
> ChangeLog:
> 2019-04-15  Alexandra Hajkova  <ahajkova@redhat.com>
>
>         * elf/Makefile (test-container): Add tst-ldconfig-bad-aux-cache.
>         * elf/tst-ldconfig-bad-aux-cache.c: New file.
>         * elf/tst-ldconfig_aux-cache.root: New directory.
>         * elf/tst-ldconfig_aux-cache.root/var: Likewise.
>         * elf/tst-ldconfig_aux-cache.root/var/cache: Likewise.
>         * elf/tst-ldconfig_aux-cache.root/var/cache/.gitignore: New file.
>
> ---
>  elf/Makefile                                  |   3 +
>  elf/tst-ldconfig-bad-aux-cache.c              | 123 ++++++++++++++++++
>  .../var/cache/.gitignore                      |   0
>  3 files changed, 126 insertions(+)
>  create mode 100644 elf/tst-ldconfig-bad-aux-cache.c
>  create mode 100644 elf/tst-ldconfig-bad-aux-cache.root/var/cache/.gitignore
>
> diff --git a/elf/Makefile b/elf/Makefile
> index 310a37cc13..35052b2768 100644
> --- a/elf/Makefile
> +++ b/elf/Makefile
> @@ -155,6 +155,9 @@ tests-static-internal := tst-tls1-static tst-tls2-static \
>  CRT-tst-tls1-static-non-pie := $(csu-objpfx)crt1.o
>  tst-tls1-static-non-pie-no-pie = yes
>
> +tests-container = \
> +                         tst-ldconfig-bad-aux-cache
> +
>  tests := tst-tls9 tst-leaks1 \
>         tst-array1 tst-array2 tst-array3 tst-array4 tst-array5 \
>         tst-auxv
> diff --git a/elf/tst-ldconfig-bad-aux-cache.c b/elf/tst-ldconfig-bad-aux-cache.c
> new file mode 100644
> index 0000000000..d7e591b9ca
> --- /dev/null
> +++ b/elf/tst-ldconfig-bad-aux-cache.c
> @@ -0,0 +1,123 @@
> +/* Test ldconfig does not segfault when aux-cache is corrupted (Bug 18093).
> +   Copyright (C) 2019 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public License as
> +   published by the Free Software Foundation; either version 2.1 of the
> +   License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; see the file COPYING.LIB.  If
> +   not, see <http://www.gnu.org/licenses/>.  */
> +
> +/* This test does the following:
> +   Run ldconfig to create the caches.
> +   Corrupt the caches.
> +   Run ldconfig again.
> +   At each step we verify that ldconfig does not crash.  */
> +
> +#include <stdio.h>
> +#include <string.h>
> +#include <unistd.h>
> +#include <errno.h>
> +#include <sys/wait.h>
> +#include <ftw.h>
> +#include <stdint.h>
> +
> +#include <support/check.h>
> +#include <support/support.h>
> +
> +static int
> +display_info (const char *fpath, const struct stat *sb,
> +              int tflag, struct FTW *ftwbuf)
> +{
> +  printf ("%-3s %2d %7jd   %-40s %d %s\n",
> +          (tflag == FTW_D) ? "d" : (tflag == FTW_DNR) ? "dnr" :
> +          (tflag == FTW_DP) ? "dp" : (tflag == FTW_F) ? "f" :
> +          (tflag == FTW_NS) ? "ns" : (tflag == FTW_SL) ? "sl" :
> +          (tflag == FTW_SLN) ? "sln" : "???",
> +          ftwbuf->level, (intmax_t) sb->st_size,
> +          fpath, ftwbuf->base, fpath + ftwbuf->base);
> +  /* To tell nftw() to continue */
> +  return 0;
> +}
> +
> +/* Run ldconfig with a corrupt aux-cache, in particular we test for size
> +   truncation that might happen if a previous ldconfig run failed or if
> +   there were storage or power issues while we were writing the file.
> +   We want ldconfig not to crash, and it should be able to do so by
> +   computing the expected size of the file (bug 18093).  */
> +static int
> +do_test (void)
> +{
> +  char *args[] = { (char *) "/sbin/ldconfig", NULL };
> +  struct stat fs;
> +  long int size, new_size, i;
> +  int status;
> +  pid_t pid = fork ();
> +
> +  /* Run ldconfig fist to generate the aux-cache.  */
> +  if (!pid)
> +    {
> +      execv (args[0], args);
> +    }
> +  else
> +    {
> +      if (pid)
> +        {
> +          waitpid (pid, &status, 0);
> +          if (!(WIFEXITED (status)))
> +            FAIL_EXIT1 ("ldconfig was aborted");
> +          if (stat ("/var/cache/ldconfig/aux-cache", &fs) < 0)
> +            {
> +              if (errno == ENOENT)
> +                FAIL_EXIT1 ("aux-cache does not exist\n");
> +              else
> +                FAIL_EXIT1 ("Failed to open aux-cache.");
> +              return -1;
> +            }
> +
> +          size = fs.st_size;
> +          /* Run 3 tests, each truncating aux-cache shorter and shorter.  */
> +          for (i = 3; i > 0; i--)
> +            {
> +              new_size = size * i / 4;
> +              truncate ("/var/cache/ldconfig/aux-cache", new_size);
> +              if (errno)
> +                FAIL_EXIT1 ("Truncation failed.");
> +              if (nftw
> +                  ("/var/cache/ldconfig/aux-cache", display_info, 1000,
> +                   0) == -1)
> +                {
> +                  FAIL_EXIT1 ("nftw failed.");
> +                  return -1;
> +                }
> +
> +              pid = fork ();
> +              /* Verify that ldconfig can run with a truncated
> +                 aux-cache and doesn't crash.  */
> +              if (!pid)
> +                {
> +                  execv (args[0], args);
> +                }
> +              else
> +                {
> +                  waitpid (pid, &status, 0);
> +                  if (!(WIFEXITED (status)))
> +                    FAIL_EXIT1 ("ldconfig exited with non-zero status");
> +                }
> +
> +            }
> +        }
> +    }
> +
> +  return 0;
> +}
> +
> +#include <support/test-driver.c>
> diff --git a/elf/tst-ldconfig-bad-aux-cache.root/var/cache/.gitignore b/elf/tst-ldconfig-bad-aux-cache.root/var/cache/.gitignore
> new file mode 100644
> index 0000000000..e69de29bb2
> --
> 2.17.2
>


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