public inbox for libc-stable@sourceware.org
 help / color / mirror / Atom feed
From: Carlos O'Donell <carlos@redhat.com>
To: libc-stable@sourceware.org
Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org>,
	Carlos O'Donell <carlos@redhat.com>
Subject: [PATCH 21/27] elf: Fix initial-exec TLS access on audit modules (BZ #28096)
Date: Tue, 12 Apr 2022 14:41:59 -0400	[thread overview]
Message-ID: <20220412184205.3343677-22-carlos@redhat.com> (raw)
In-Reply-To: <20220412184205.3343677-1-carlos@redhat.com>

From: Adhemerval Zanella <adhemerval.zanella@linaro.org>

For audit modules and dependencies with initial-exec TLS, we can not
set the initial TLS image on default loader initialization because it
would already be set by the audit setup.  However, subsequent thread
creation would need to follow the default behaviour.

This patch fixes it by setting l_auditing link_map field not only
for the audit modules, but also for all its dependencies.  This is
used on _dl_allocate_tls_init to avoid the static TLS initialization
at load time.

Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 254d3d5aef2fd8430c469e1938209ac100ebf132)
---
 elf/Makefile               |  8 ++++
 elf/dl-tls.c               | 17 ++++++--
 elf/rtld.c                 |  2 +-
 elf/tst-audit21.c          | 42 ++++++++++++++++++++
 elf/tst-auditmod21a.c      | 80 ++++++++++++++++++++++++++++++++++++++
 elf/tst-auditmod21b.c      | 22 +++++++++++
 nptl/allocatestack.c       |  2 +-
 sysdeps/generic/ldsodefs.h |  2 +-
 8 files changed, 169 insertions(+), 6 deletions(-)
 create mode 100644 elf/tst-audit21.c
 create mode 100644 elf/tst-auditmod21a.c
 create mode 100644 elf/tst-auditmod21b.c

diff --git a/elf/Makefile b/elf/Makefile
index 6e8cd02cc2..252841f6e5 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -356,6 +356,7 @@ tests += \
   tst-audit18 \
   tst-audit19b \
   tst-audit20 \
+  tst-audit21 \
   tst-audit22 \
   tst-audit23 \
   tst-auditmany \
@@ -638,6 +639,8 @@ modules-names = \
   tst-auditmod19a \
   tst-auditmod19b \
   tst-auditmod20 \
+  tst-auditmod21a \
+  tst-auditmod21b \
   tst-auditmod22 \
   tst-auditmod23 \
   tst-auxvalmod \
@@ -2001,6 +2004,11 @@ tst-audit19b-ARGS = -- $(host-test-program-cmd)
 $(objpfx)tst-audit20.out: $(objpfx)tst-auditmod20.so
 tst-audit20-ENV = LD_AUDIT=$(objpfx)tst-auditmod20.so
 
+$(objpfx)tst-audit21: $(shared-thread-library)
+$(objpfx)tst-audit21.out: $(objpfx)tst-auditmod21a.so
+$(objpfx)tst-auditmod21a.so: $(objpfx)tst-auditmod21b.so
+tst-audit21-ENV = LD_AUDIT=$(objpfx)tst-auditmod21a.so
+
 $(objpfx)tst-audit22.out: $(objpfx)tst-auditmod22.so
 tst-audit22-ARGS = -- $(host-test-program-cmd)
 
diff --git a/elf/dl-tls.c b/elf/dl-tls.c
index 40263cf586..0070c8bbaa 100644
--- a/elf/dl-tls.c
+++ b/elf/dl-tls.c
@@ -519,8 +519,12 @@ _dl_resize_dtv (dtv_t *dtv, size_t max_modid)
 }
 
 
+/* Allocate initial TLS.  RESULT should be a non-NULL pointer to storage
+   for the TLS space.  The DTV may be resized, and so this function may
+   call malloc to allocate that space.  The loader's GL(dl_load_tls_lock)
+   is taken when manipulating global TLS-related data in the loader.  */
 void *
-_dl_allocate_tls_init (void *result)
+_dl_allocate_tls_init (void *result, bool init_tls)
 {
   if (result == NULL)
     /* The memory allocation failed.  */
@@ -593,7 +597,14 @@ _dl_allocate_tls_init (void *result)
 	     some platforms use in static programs requires it.  */
 	  dtv[map->l_tls_modid].pointer.val = dest;
 
-	  /* Copy the initialization image and clear the BSS part.  */
+	  /* Copy the initialization image and clear the BSS part.  For
+	     audit modules or dependencies with initial-exec TLS, we can not
+	     set the initial TLS image on default loader initialization
+	     because it would already be set by the audit setup.  However,
+	     subsequent thread creation would need to follow the default
+	     behaviour.   */
+	  if (map->l_ns != LM_ID_BASE && !init_tls)
+	    continue;
 	  memset (__mempcpy (dest, map->l_tls_initimage,
 			     map->l_tls_initimage_size), '\0',
 		  map->l_tls_blocksize - map->l_tls_initimage_size);
@@ -620,7 +631,7 @@ _dl_allocate_tls (void *mem)
 {
   return _dl_allocate_tls_init (mem == NULL
 				? _dl_allocate_tls_storage ()
-				: allocate_dtv (mem));
+				: allocate_dtv (mem), true);
 }
 rtld_hidden_def (_dl_allocate_tls)
 
diff --git a/elf/rtld.c b/elf/rtld.c
index 83c12f8b8b..4427e9abe6 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -2392,7 +2392,7 @@ dl_main (const ElfW(Phdr) *phdr,
      into the main thread's TLS area, which we allocated above.
      Note: thread-local variables must only be accessed after completing
      the next step.  */
-  _dl_allocate_tls_init (tcbp);
+  _dl_allocate_tls_init (tcbp, false);
 
   /* And finally install it for the main thread.  */
   if (! tls_init_tp_called)
diff --git a/elf/tst-audit21.c b/elf/tst-audit21.c
new file mode 100644
index 0000000000..3a47ab64d4
--- /dev/null
+++ b/elf/tst-audit21.c
@@ -0,0 +1,42 @@
+/* Check LD_AUDIT with static TLS.
+   Copyright (C) 2022 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 <ctype.h>
+#include <support/xthread.h>
+#include <support/check.h>
+
+static volatile __thread int out __attribute__ ((tls_model ("initial-exec")));
+
+static void *
+tf (void *arg)
+{
+  TEST_COMPARE (out, 0);
+  out = isspace (' ');
+  return NULL;
+}
+
+int main (int argc, char *argv[])
+{
+  TEST_COMPARE (out, 0);
+  out = isspace (' ');
+
+  pthread_t t = xpthread_create (NULL, tf, NULL);
+  xpthread_join (t);
+
+  return 0;
+}
diff --git a/elf/tst-auditmod21a.c b/elf/tst-auditmod21a.c
new file mode 100644
index 0000000000..f6d51b5c05
--- /dev/null
+++ b/elf/tst-auditmod21a.c
@@ -0,0 +1,80 @@
+/* Check LD_AUDIT with static TLS.
+   Copyright (C) 2022 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 <ctype.h>
+#include <stdlib.h>
+#include <link.h>
+
+#define tls_ie __attribute__ ((tls_model ("initial-exec")))
+
+__thread int tls_var0 tls_ie;
+__thread int tls_var1 tls_ie = 0x10;
+
+/* Defined at tst-auditmod21b.so  */
+extern __thread int tls_var2;
+extern __thread int tls_var3;
+
+static volatile int out;
+
+static void
+call_libc (void)
+{
+  /* isspace accesses the initial-exec glibc TLS variables, which are
+     setup in glibc initialization.  */
+  out = isspace (' ');
+}
+
+unsigned int
+la_version (unsigned int v)
+{
+  tls_var0 = 0x1;
+  if (tls_var1 != 0x10)
+    abort ();
+  tls_var1 = 0x20;
+
+  tls_var2 = 0x2;
+  if (tls_var3 != 0x20)
+    abort ();
+  tls_var3 = 0x40;
+
+  call_libc ();
+
+  return LAV_CURRENT;
+}
+
+unsigned int
+la_objopen (struct link_map* map, Lmid_t lmid, uintptr_t* cookie)
+{
+  call_libc ();
+  *cookie = (uintptr_t) map;
+  return 0;
+}
+
+void
+la_activity (uintptr_t* cookie, unsigned int flag)
+{
+  if (tls_var0 != 0x1 || tls_var1 != 0x20)
+    abort ();
+  call_libc ();
+}
+
+void
+la_preinit (uintptr_t* cookie)
+{
+  call_libc ();
+}
diff --git a/elf/tst-auditmod21b.c b/elf/tst-auditmod21b.c
new file mode 100644
index 0000000000..6ba5335b75
--- /dev/null
+++ b/elf/tst-auditmod21b.c
@@ -0,0 +1,22 @@
+/* Check LD_AUDIT with static TLS.
+   Copyright (C) 2022 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/>.  */
+
+#define tls_ie __attribute__ ((tls_model ("initial-exec")))
+
+__thread int tls_var2 tls_ie;
+__thread int tls_var3 tls_ie = 0x20;
diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c
index 50065bc9bd..554a721f81 100644
--- a/nptl/allocatestack.c
+++ b/nptl/allocatestack.c
@@ -139,7 +139,7 @@ get_cached_stack (size_t *sizep, void **memp)
   memset (dtv, '\0', (dtv[-1].counter + 1) * sizeof (dtv_t));
 
   /* Re-initialize the TLS.  */
-  _dl_allocate_tls_init (TLS_TPADJ (result));
+  _dl_allocate_tls_init (TLS_TPADJ (result), true);
 
   return result;
 }
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index 14a306c306..f8570f2852 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -1242,7 +1242,7 @@ extern void _dl_allocate_static_tls (struct link_map *map) attribute_hidden;
 /* These are internal entry points to the two halves of _dl_allocate_tls,
    only used within rtld.c itself at startup time.  */
 extern void *_dl_allocate_tls_storage (void) attribute_hidden;
-extern void *_dl_allocate_tls_init (void *);
+extern void *_dl_allocate_tls_init (void *, bool);
 rtld_hidden_proto (_dl_allocate_tls_init)
 
 /* Deallocate memory allocated with _dl_allocate_tls.  */
-- 
2.35.1


  parent reply	other threads:[~2022-04-12 18:42 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-12 18:41 [PATCH 00/27] Improve LD_AUDIT support in glibc 2.34 Carlos O'Donell
2022-04-12 18:41 ` [PATCH 01/27] powerpc: Delete unneeded ELF_MACHINE_BEFORE_RTLD_RELOC Carlos O'Donell
2022-04-12 18:41 ` [PATCH 02/27] elf: Avoid nested functions in the loader [BZ #27220] Carlos O'Donell
2022-04-12 18:41 ` [PATCH 03/27] elf: Fix elf_get_dynamic_info definition Carlos O'Donell
2022-04-12 18:41 ` [PATCH 04/27] elf: Fix dynamic-link.h usage on rtld.c Carlos O'Donell
2022-04-12 18:41 ` [PATCH 05/27] elf: Fix elf_get_dynamic_info() for bootstrap Carlos O'Donell
2022-04-12 18:41 ` [PATCH 06/27] elf: Move LAV_CURRENT to link_lavcurrent.h Carlos O'Donell
2022-04-12 18:41 ` [PATCH 07/27] elf: Move la_activity (LA_ACT_ADD) after _dl_add_to_namespace_list() (BZ #28062) Carlos O'Donell
2022-04-12 18:41 ` [PATCH 08/27] elf: Add _dl_audit_objopen Carlos O'Donell
2022-04-12 18:41 ` [PATCH 09/27] elf: Add _dl_audit_activity_map and _dl_audit_activity_nsid Carlos O'Donell
2022-04-12 18:41 ` [PATCH 10/27] elf: Add _dl_audit_objsearch Carlos O'Donell
2022-04-12 18:41 ` [PATCH 11/27] elf: Add _dl_audit_objclose Carlos O'Donell
2022-04-12 18:41 ` [PATCH 12/27] elf: Add _dl_audit_symbind_alt and _dl_audit_symbind Carlos O'Donell
2022-04-12 18:41 ` [PATCH 13/27] elf: Add _dl_audit_preinit Carlos O'Donell
2022-04-12 18:41 ` [PATCH 14/27] elf: Add _dl_audit_pltenter Carlos O'Donell
2022-04-12 18:41 ` [PATCH 15/27] elf: Add _dl_audit_pltexit Carlos O'Donell
2022-04-12 18:41 ` [PATCH 16/27] elf: Avoid unnecessary slowdown from profiling with audit (BZ#15533) Carlos O'Donell
2022-04-12 18:41 ` [PATCH 17/27] elf: Add audit tests for modules with TLSDESC Carlos O'Donell
2022-04-12 18:41 ` [PATCH 18/27] elf: Issue audit la_objopen for vDSO Carlos O'Donell
2022-04-12 18:41 ` [PATCH 19/27] elf: Do not fail for failed dlmopen on audit modules (BZ #28061) Carlos O'Donell
2022-04-12 18:41 ` [PATCH 20/27] elf: Add la_activity during application exit Carlos O'Donell
2022-04-12 18:41 ` Carlos O'Donell [this message]
2022-04-12 18:42 ` [PATCH 22/27] elf: Issue la_symbind for bind-now (BZ #23734) Carlos O'Donell
2022-04-12 18:42 ` [PATCH 23/27] elf: Fix runtime linker auditing on aarch64 (BZ #26643) Carlos O'Donell
2022-04-12 18:42 ` [PATCH 24/27] Fix elf/tst-audit25a with default bind now toolchains Carlos O'Donell
2022-04-12 18:42 ` [PATCH 25/27] elf: Replace tst-audit24bmod2.so with tst-audit24bmod2 Carlos O'Donell
2022-04-12 18:42 ` [PATCH 26/27] hppa: Fix bind-now audit (BZ #28857) Carlos O'Donell
2022-04-12 18:42 ` [PATCH 27/27] NEWS: Update fixed bug list for LD_AUDIT backports Carlos O'Donell

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20220412184205.3343677-22-carlos@redhat.com \
    --to=carlos@redhat.com \
    --cc=adhemerval.zanella@linaro.org \
    --cc=libc-stable@sourceware.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).