[v6] elf: Add tst-ldconfig-bad-aux-cache test [BZ #18093]

Message ID 20190522071012.6749-1-ahajkova@redhat.com
State New
Headers show
Series
  • [v6] elf: Add tst-ldconfig-bad-aux-cache test [BZ #18093]
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Commit Message

Alexandra Hájková May 22, 2019, 7:10 a.m.
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.

2019-05-22 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-bad-aux-cache.root/postclean.req: New file

v6
- add an info prefix to the display_info output
- use TEST_COMPARE instead of WIFEXITED
- remove unnecessary braces
---
 elf/Makefile                                  |   3 +
 elf/tst-ldconfig-bad-aux-cache.c              | 117 ++++++++++++++++++
 .../postclean.req                             |   0
 3 files changed, 120 insertions(+)
 create mode 100644 elf/tst-ldconfig-bad-aux-cache.c
 create mode 100644 elf/tst-ldconfig-bad-aux-cache.root/postclean.req

diff --git a/elf/tst-ldconfig-bad-aux-cache.root/postclean.req b/elf/tst-ldconfig-bad-aux-cache.root/postclean.req
new file mode 100644
index 0000000000..e69de29bb2
-- 
2.17.2

Comments

Florian Weimer May 22, 2019, 8:34 a.m. | #1
* Alexandra Hájková:

>  create mode 100644 elf/tst-ldconfig-bad-aux-cache.c

>  create mode 100644 elf/tst-ldconfig-bad-aux-cache.root/postclean.req


When running the test, I see this:

/sbin/ldconfig: Warning: ignoring configuration file that cannot be opened: /etc/ld.so.conf: No such file or directory
/sbin/ldconfig: Warning: ignoring configuration file that cannot be opened: /etc/ld.so.conf: No such file or directory
/sbin/ldconfig: Warning: ignoring configuration file that cannot be opened: /etc/ld.so.conf: No such file or directory
/sbin/ldconfig: Warning: ignoring configuration file that cannot be opened: /etc/ld.so.conf: No such file or directory

I think you can suppress this message by creating a file:

  elf/tst-ldconfig-bad-aux-cache.root/etc/ld.so.conf

The file can be empty, but you can also add a comment saying that it's
there to suppress a warning from ldconfig.

This got me thinking if we need to detect that ldconfig writes to
standard error.  The error message above current lands in the .out file.
But perhaps we should defer that to a future enhancement of the test.
(It probably involves using support_capture_subprocess.)

I think with the ld.so.conf file, this is ready to push.

Thanks,
Florian

Patch

diff --git a/elf/Makefile b/elf/Makefile
index 4895489208..08e2f999bf 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -156,6 +156,9 @@  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..68ce90a956
--- /dev/null
+++ b/elf/tst-ldconfig-bad-aux-cache.c
@@ -0,0 +1,117 @@ 
+/* 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 <stdlib.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>
+#include <support/xunistd.h>
+
+#include <dirent.h>
+
+static int
+display_info (const char *fpath, const struct stat *sb,
+              int tflag, struct FTW *ftwbuf)
+{
+  printf ("info: %-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 *prog = xasprintf ("%s/ldconfig", support_install_rootsbindir);
+  char *const args[] = { prog, NULL };
+  const char *path = "/var/cache/ldconfig/aux-cache";
+  struct stat64 fs;
+  long int size, new_size, i;
+  int status;
+  pid_t pid;
+
+  /* Create the needed directories. */
+  xmkdirp ("/var/cache/ldconfig", 0777);
+
+  pid = xfork ();
+  /* Run ldconfig fist to generate the aux-cache.  */
+  if (pid == 0)
+    {
+      execv (args[0], args);
+      _exit (1);
+    }
+  else
+    {
+      xwaitpid (pid, &status, 0);
+      TEST_COMPARE(status, 0);
+      xstat (path, &fs);
+
+      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;
+          if (truncate (path, new_size))
+              FAIL_EXIT1 ("truncation failed: %m");
+          if (nftw (path, display_info, 1000, 0) == -1)
+              FAIL_EXIT1 ("nftw failed.");
+
+          pid = xfork ();
+          /* Verify that ldconfig can run with a truncated
+             aux-cache and doesn't crash.  */
+          if (pid == 0)
+            {
+              execv (args[0], args);
+              _exit (1);
+            }
+          else
+            {
+              xwaitpid (pid, &status, 0);
+              TEST_COMPARE(status, 0);
+            }
+        }
+    }
+
+  free (prog);
+  return 0;
+}
+
+#include <support/test-driver.c>