[PATCH v6 01/20] elf: Suppress audit calls when a (new) namespace is empty (BZ #28062)

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

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.
---
 elf/Makefile         |   9 ++-
 elf/dl-load.c        |  72 ++++++++++++------------
 elf/tst-audit18.c    | 129 +++++++++++++++++++++++++++++++++++++++++++
 elf/tst-audit18mod.c |  23 ++++++++
 elf/tst-auditmod18.c |  73 ++++++++++++++++++++++++
 5 files changed, 269 insertions(+), 37 deletions(-)
 create mode 100644 elf/tst-audit18.c
 create mode 100644 elf/tst-audit18mod.c
 create mode 100644 elf/tst-auditmod18.c

diff --git a/elf/Makefile b/elf/Makefile
index a311c3e23c..8f3e3a3602 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -229,7 +229,8 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \
 	 tst-tls-ie tst-tls-ie-dlmopen argv0test \
 	 tst-glibc-hwcaps tst-glibc-hwcaps-prepend tst-glibc-hwcaps-mask \
 	 tst-tls20 tst-tls21 tst-dlmopen-dlerror tst-dlmopen-gethostbyname \
-	 tst-dl-is_dso tst-ro-dynamic
+	 tst-dl-is_dso tst-ro-dynamic \
+	 tst-audit18 \
 #	 reldep9
 tests-internal += loadtest unload unload2 circleload1 \
 	 neededtest neededtest2 neededtest3 neededtest4 \
@@ -370,6 +371,8 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
 		tst-tls20mod-bad tst-tls21mod tst-dlmopen-dlerror-mod \
 		tst-auxvalmod \
 		tst-dlmopen-gethostbyname-mod tst-ro-dynamic-mod \
+		tst-auditmod18 \
+		tst-audit18mod \
 
 # Most modules build with _ISOMAC defined, but those filtered out
 # depend on internal headers.
@@ -1537,6 +1540,10 @@ $(objpfx)tst-audit16-cmp.out: tst-audit16.exp $(objpfx)tst-audit16.out
 	cmp $^ > $@; \
 	$(evaluate-test)
 
+$(objpfx)tst-audit18.out: $(objpfx)tst-auditmod18.so \
+			  $(objpfx)tst-audit18mod.so
+tst-audit18-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 9f4fa9617d..9538bcb7dc 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -1058,42 +1058,6 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
   /* This is the ELF header.  We read it in `open_verify'.  */
   header = (void *) fbp->buf;
 
-  /* Signal that we are going to add new objects.  */
-  if (r->r_state == RT_CONSISTENT)
-    {
-#ifdef SHARED
-      /* Auditing checkpoint: we are going to add new objects.  */
-      if ((mode & __RTLD_AUDIT) == 0
-	  && __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)
-	    {
-	      struct audit_ifaces *afct = GLRO(dl_audit);
-	      for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
-		{
-		  if (afct->activity != NULL)
-		    afct->activity (&link_map_audit_state (head, cnt)->cookie,
-				    LA_ACT_ADD);
-
-		  afct = afct->next;
-		}
-	    }
-	}
-#endif
-
-      /* Notify the debugger we have added some objects.  We need to
-	 call _dl_debug_initialize in a static program in case dynamic
-	 linking has not been used before.  */
-      r->r_state = RT_ADD;
-      _dl_debug_state ();
-      LIBC_PROBE (map_start, 2, nsid, r);
-      make_consistent = true;
-    }
-  else
-    assert (r->r_state == RT_ADD);
-
   /* Enter the new object in the list of loaded objects.  */
   l = _dl_new_object (realname, name, l_type, loader, mode, nsid);
   if (__glibc_unlikely (l == NULL))
@@ -1515,6 +1479,42 @@ cannot enable executable stack as shared object requires");
   /* Now that the object is fully initialized add it to the object list.  */
   _dl_add_to_namespace_list (l, nsid);
 
+  /* Signal that we are going to add new objects.  */
+  if (r->r_state == RT_CONSISTENT)
+    {
+#ifdef SHARED
+      /* Auditing checkpoint: we are going to add new objects.  */
+      if ((mode & __RTLD_AUDIT) == 0
+	  && __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)
+	    {
+	      struct audit_ifaces *afct = GLRO(dl_audit);
+	      for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
+		{
+		  if (afct->activity != NULL)
+		    afct->activity (&link_map_audit_state (head, cnt)->cookie,
+				    LA_ACT_ADD);
+
+		  afct = afct->next;
+		}
+	    }
+	}
+#endif
+
+      /* Notify the debugger we have added some objects.  We need to
+	 call _dl_debug_initialize in a static program in case dynamic
+	 linking has not been used before.  */
+      r->r_state = RT_ADD;
+      _dl_debug_state ();
+      LIBC_PROBE (map_start, 2, nsid, r);
+      make_consistent = true;
+    }
+  else
+    assert (r->r_state == RT_ADD);
+
 #ifdef SHARED
   /* Auditing checkpoint: we have a new object.  */
   if (__glibc_unlikely (GLRO(dl_naudit) > 0)
diff --git a/elf/tst-audit18.c b/elf/tst-audit18.c
new file mode 100644
index 0000000000..b5ed15d07f
--- /dev/null
+++ b/elf/tst-audit18.c
@@ -0,0 +1,129 @@
+/* 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-audit18mod.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-auditmod18.so", 0);
+  struct support_capture_subprocess result
+    = support_capture_subprogram (spargv[0], spargv);
+  support_capture_subprocess_check (&result, "tst-audit18", 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 the test only check if any
+     is 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-audit18mod.c b/elf/tst-audit18mod.c
new file mode 100644
index 0000000000..096a9167c9
--- /dev/null
+++ b/elf/tst-audit18mod.c
@@ -0,0 +1,23 @@
+/* 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/>.  */
+
+int
+foo (void)
+{
+  return 10;
+}
diff --git a/elf/tst-auditmod18.c b/elf/tst-auditmod18.c
new file mode 100644
index 0000000000..182992e9fd
--- /dev/null
+++ b/elf/tst-auditmod18.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;
+}
-- 
2.32.0