diff mbox series

[5/5] elf: Suppress audit calls when a (new) namespace is empty (BZ #28062)

Message ID 20210707182610.3940620-6-adhemerval.zanella@linaro.org
State Superseded
Headers show
Series Some rtld-audit fixes | expand

Checks

Context Check Description
dj/TryBot-apply_patch success Patch applied to master at the time it was sent
dj/TryBot-32bit success Build for i686

Commit Message

Adhemerval Zanella July 7, 2021, 6:26 p.m. UTC
From: Vivek Das Mohapatra <vivek@collabora.com>

For a new Lmid_t the namespace link_map list are empty, so it requires
to check if before using it.  This can happen for when audit module
is used along with dlmopen.

Checked on x86_64-linux-gnu.

Co-authored-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
---
 elf/Makefile         |   7 ++-
 elf/dl-load.c        |   7 ++-
 elf/tst-audit20.c    | 128 +++++++++++++++++++++++++++++++++++++++++++
 elf/tst-audit20mod.c |  26 +++++++++
 elf/tst-auditmod20.c |  73 ++++++++++++++++++++++++
 5 files changed, 238 insertions(+), 3 deletions(-)
 create mode 100644 elf/tst-audit20.c
 create mode 100644 elf/tst-audit20mod.c
 create mode 100644 elf/tst-auditmod20.c
diff mbox series

Patch

diff --git a/elf/Makefile b/elf/Makefile
index 513b7e68a2..53868909c5 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -220,7 +220,7 @@  tests += restest1 preloadtest loadfail multiload origtest resolvfail \
 	 tst-dlopenfail-2 \
 	 tst-filterobj tst-filterobj-dlopen tst-auxobj tst-auxobj-dlopen \
 	 tst-audit14 tst-audit15 tst-audit16 tst-audit17 tst-audit18a \
-	 tst-audit18b tst-audit19 \
+	 tst-audit18b tst-audit19 tst-audit20 \
 	 tst-single_threaded tst-single_threaded-pthread \
 	 tst-tls-ie tst-tls-ie-dlmopen argv0test \
 	 tst-glibc-hwcaps tst-glibc-hwcaps-prepend tst-glibc-hwcaps-mask \
@@ -296,6 +296,7 @@  modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
 		tst-unique2mod1 tst-unique2mod2 \
 		tst-auditmod9a tst-auditmod9b \
 		tst-auditmod18a tst-audit18bmod tst-auditmod18b tst-auditmod19 \
+		tst-auditmod20 tst-audit20mod \
 		$(if $(CXX),tst-unique3lib tst-unique3lib2 tst-unique4lib \
 		  tst-nodelete-uniquemod tst-nodelete-rtldmod \
 		  tst-nodelete-zmod \
@@ -1505,6 +1506,10 @@  tst-audit18b-ENV = LD_AUDIT=$(objpfx)tst-auditmod18b.so
 $(objpfx)tst-audit19.out: $(objpfx)tst-auditmod19.so
 tst-audit19-ENV = LD_AUDIT=$(objpfx)tst-auditmod19.so
 
+$(objpfx)tst-audit20.out: $(objpfx)tst-auditmod20.so \
+			  $(objpfx)tst-audit20mod.so
+tst-audit20-ARGS = -- $(host-test-program-cmd)
+
 # tst-sonamemove links against an older implementation of the library.
 LDFLAGS-tst-sonamemove-linkmod1.so = \
   -Wl,--version-script=tst-sonamemove-linkmod1.map \
diff --git a/elf/dl-load.c b/elf/dl-load.c
index a08df001af..d2075f3c02 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -1062,8 +1062,11 @@  _dl_map_object_from_fd (const char *name, const char *origname, int fd,
 	  && __glibc_unlikely (GLRO(dl_naudit) > 0))
 	{
 	  struct link_map *head = GL(dl_ns)[nsid]._ns_loaded;
-	  /* Do not call the functions for any auditing object.  */
-	  if (head->l_auditing == 0)
+	  /* Do not call the functions for any auditing object and also do not
+	     try to call auditing functions if the namespace is currently
+	     empty.  This happens when opening the first DSO in a new
+	     namespace.  */
+	  if (head != NULL && head->l_auditing == 0)
 	    {
 	      struct audit_ifaces *afct = GLRO(dl_audit);
 	      for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
diff --git a/elf/tst-audit20.c b/elf/tst-audit20.c
new file mode 100644
index 0000000000..5c5d42b723
--- /dev/null
+++ b/elf/tst-audit20.c
@@ -0,0 +1,128 @@ 
+/* Check DT_AUDIT with dlmopen.
+   Copyright (C) 2021 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <array_length.h>
+#include <getopt.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <gnu/lib-names.h>
+#include <support/capture_subprocess.h>
+#include <support/check.h>
+#include <support/xdlfcn.h>
+#include <support/xstdio.h>
+#include <support/support.h>
+
+static int restart;
+#define CMDLINE_OPTIONS \
+  { "restart", no_argument, &restart, 1 },
+
+static int
+handle_restart (void)
+{
+  {
+    void *h = xdlmopen (LM_ID_NEWLM, LIBC_SO, RTLD_NOW);
+
+    pid_t (*s)(void) = xdlsym (h, "getpid");
+    TEST_COMPARE (s (), getpid ());
+
+    xdlclose (h);
+  }
+
+  {
+    void *h = xdlmopen (LM_ID_NEWLM, "tst-audit20mod.so", RTLD_NOW);
+
+    int (*foo)(void) = xdlsym (h, "foo");
+    TEST_COMPARE (foo (), 10);
+
+    xdlclose (h);
+  }
+
+  return 0;
+}
+
+static int
+do_test (int argc, char *argv[])
+{
+  /* We must have either:
+     - One our fource parameters left if called initially:
+       + path to ld.so         optional
+       + "--library-path"      optional
+       + the library path      optional
+       + the application name  */
+
+  if (restart)
+    return handle_restart ();
+
+  char *spargv[9];
+  int i = 0;
+  for (; i < argc - 1; i++)
+    spargv[i] = argv[i + 1];
+  spargv[i++] = (char *) "--direct";
+  spargv[i++] = (char *) "--restart";
+  spargv[i] = NULL;
+
+  setenv ("LD_AUDIT", "tst-auditmod20.so", 0);
+  struct support_capture_subprocess result
+    = support_capture_subprogram (spargv[0], spargv);
+  support_capture_subprocess_check (&result, "tst-audit20", 0, sc_allow_stderr);
+
+  struct
+  {
+    const char *name;
+    bool found;
+  } audit_iface[] =
+  {
+    { "la_version", false },
+    { "la_objsearch", false },
+    { "la_activity", false },
+    { "la_objopen", false },
+    { "la_objclose", false },
+    { "la_preinit", false },
+#if __WORDSIZE == 32
+    { "la_symbind32", false },
+#elif __WORDSIZE == 64
+    { "la_symbind64", false },
+#endif
+  };
+
+  /* Some hooks are called more than once but it only checkis if they are
+     called at least once.  */
+  FILE *out = fmemopen (result.err.buffer, result.err.length, "r");
+  TEST_VERIFY (out != NULL);
+  char *buffer = NULL;
+  size_t buffer_length = 0;
+  while (xgetline (&buffer, &buffer_length, out)) {
+    for (int i = 0; i < array_length (audit_iface); i++)
+      if (strncmp (buffer, audit_iface[i].name,
+		   strlen (audit_iface[i].name)) == 0)
+	audit_iface[i].found = true;
+  }
+  free (buffer);
+  xfclose (out);
+
+  for (int i = 0; i < array_length (audit_iface); i++)
+    TEST_COMPARE (audit_iface[i].found, true);
+
+  support_capture_subprocess_free (&result);
+
+  return 0;
+}
+
+#define TEST_FUNCTION_ARGV do_test
+#include <support/test-driver.c>
diff --git a/elf/tst-audit20mod.c b/elf/tst-audit20mod.c
new file mode 100644
index 0000000000..f229c4139b
--- /dev/null
+++ b/elf/tst-audit20mod.c
@@ -0,0 +1,26 @@ 
+/* Check DT_AUDIT with dlmopen.
+   Copyright (C) 2021 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <fcntl.h>
+#include <gnu/lib-names.h>
+
+int
+foo (void)
+{
+  return 10;
+}
diff --git a/elf/tst-auditmod20.c b/elf/tst-auditmod20.c
new file mode 100644
index 0000000000..182992e9fd
--- /dev/null
+++ b/elf/tst-auditmod20.c
@@ -0,0 +1,73 @@ 
+/* Check DT_AUDIT with dlmopen.
+   Copyright (C) 2021 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <stdio.h>
+#include <link.h>
+
+unsigned int
+la_version (unsigned int version)
+{
+  fprintf (stderr, "%s\n", __func__);
+  return LAV_CURRENT;
+}
+
+char *
+la_objsearch (const char *name, uintptr_t *cookie, unsigned int flag)
+{
+  fprintf (stderr, "%s\n", __func__);
+  return (char *) name;
+}
+
+void
+la_activity (uintptr_t *cookie, unsigned int flag)
+{
+  fprintf (stderr, "%s\n", __func__);
+}
+
+unsigned int
+la_objopen (struct link_map *map, Lmid_t lmid, uintptr_t *cookie)
+{
+  fprintf (stderr, "%s\n", __func__);
+  return LA_FLG_BINDTO | LA_FLG_BINDFROM;
+}
+
+unsigned int
+la_objclose (uintptr_t *cookie)
+{
+  fprintf (stderr, "%s\n", __func__);
+  return 0;
+}
+
+void
+la_preinit (uintptr_t *cookie)
+{
+  fprintf (stderr, "%s\n", __func__);
+}
+
+uintptr_t
+#if __ELF_NATIVE_CLASS == 32
+la_symbind32 (Elf32_Sym *sym, unsigned int ndx, uintptr_t *refcook,
+              uintptr_t *defcook, unsigned int *flags, const char *symname)
+#else
+la_symbind64 (Elf64_Sym *sym, unsigned int ndx, uintptr_t *refcook,
+              uintptr_t *defcook, unsigned int *flags, const char *symname)
+#endif
+{
+  fprintf (stderr, "%s\n", __func__);
+  return sym->st_value;
+}