elf: Refuse to dlopen PIE objects [BZ #24323]

Another executable has already been mapped, so the dynamic linker
cannot perform relocations correctly for the second executable.

1 files changed, 49 insertions, 0 deletions

diff --git a/elf/tst-dlopen-pie.c b/elf/tst-dlopen-pie.c
new file mode 100644
index 0000000000..6a41c731cb
--- /dev/null
+++ b/elf/tst-dlopen-pie.c
@@ -0,0 +1,49 @@
+/* dlopen test for PIE objects.
+   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; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* This test attempts to open the (otherwise unrelated) PIE test
+   program elf/tst-pie1 and expects the attempt to fail.  */
+
+#include <dlfcn.h>
+#include <stddef.h>
+#include <string.h>
+#include <support/check.h>
+#include <support/support.h>
+
+static void
+test_mode (int mode)
+{
+  char *pie_path = xasprintf ("%s/elf/tst-pie1", support_objdir_root);
+  if (dlopen (pie_path, mode) != NULL)
+    FAIL_EXIT1 ("dlopen succeeded unexpectedly (%d)", mode);
+  const char *message = dlerror ();
+  const char *expected
+    = "cannot dynamically load position-independent executable";
+  if (strstr (message, expected) == NULL)
+    FAIL_EXIT1 ("unexpected error message (mode %d): %s", mode, message);
+}
+
+static int
+do_test (void)
+{
+  test_mode (RTLD_LAZY);
+  test_mode (RTLD_NOW);
+  return 0;
+}
+
+#include <support/test-driver.c>