421 lines
14 KiB
Diff
421 lines
14 KiB
Diff
commit 674ea88294bfb8d89878a0ebbbcec38a85e118a5
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Author: H.J. Lu <hjl.tools@gmail.com>
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Date: Tue Apr 28 10:05:25 2020 -0700
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x86: Move CET control to _dl_x86_feature_control [BZ #25887]
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1. Include <dl-procruntime.c> to get architecture specific initializer in
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rtld_global.
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2. Change _dl_x86_feature_1[2] to _dl_x86_feature_1.
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3. Add _dl_x86_feature_control after _dl_x86_feature_1, which is a
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struct of 2 bitfields for IBT and SHSTK control
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This fixes [BZ #25887].
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---
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diff --git a/elf/rtld.c b/elf/rtld.c
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index e107bd1..7f030f7 100644
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--- a/elf/rtld.c
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+++ b/elf/rtld.c
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@@ -230,6 +230,8 @@ rtld_hidden_def (_dl_starting_up)
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(except those which cannot be added for some reason). */
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struct rtld_global _rtld_global =
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{
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+ /* Get architecture specific initializer. */
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+#include <dl-procruntime.c>
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/* Generally the default presumption without further information is an
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* executable stack but this is not true for all platforms. */
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._dl_stack_flags = DEFAULT_STACK_PERMS,
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diff --git a/sysdeps/i386/dl-machine.h b/sysdeps/i386/dl-machine.h
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index f6cfb90..8c959e3 100644
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--- a/sysdeps/i386/dl-machine.h
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+++ b/sysdeps/i386/dl-machine.h
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@@ -71,7 +71,7 @@ elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
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extern void _dl_runtime_profile_shstk (Elf32_Word) attribute_hidden;
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/* Check if SHSTK is enabled by kernel. */
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bool shstk_enabled
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- = (GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0;
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+ = (GL(dl_x86_feature_1) & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0;
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if (l->l_info[DT_JMPREL] && lazy)
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{
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diff --git a/sysdeps/unix/sysv/linux/x86/cpu-features.c b/sysdeps/unix/sysv/linux/x86/cpu-features.c
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index 8566a26..9f40624 100644
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--- a/sysdeps/unix/sysv/linux/x86/cpu-features.c
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+++ b/sysdeps/unix/sysv/linux/x86/cpu-features.c
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@@ -36,7 +36,7 @@ static inline void
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x86_setup_tls (void)
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{
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__libc_setup_tls ();
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- THREAD_SETMEM (THREAD_SELF, header.feature_1, GL(dl_x86_feature_1)[0]);
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+ THREAD_SETMEM (THREAD_SELF, header.feature_1, GL(dl_x86_feature_1));
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}
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# define ARCH_SETUP_TLS() x86_setup_tls ()
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diff --git a/sysdeps/x86/cet-control.h b/sysdeps/x86/cet-control.h
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new file mode 100644
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index 0000000..7b29f95
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--- /dev/null
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+++ b/sysdeps/x86/cet-control.h
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@@ -0,0 +1,41 @@
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+/* x86 CET tuning.
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+ This file is part of the GNU C Library.
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+ Copyright (C) 2018 Free Software Foundation, Inc.
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+
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+ The GNU C Library is free software; you can redistribute it and/or
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+ modify it under the terms of the GNU Lesser General Public
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+ License as published by the Free Software Foundation; either
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+ version 2.1 of the License, or (at your option) any later version.
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+
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+ The GNU C Library is distributed in the hope that it will be useful,
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+ but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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+ Lesser General Public License for more details.
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+
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+ You should have received a copy of the GNU Lesser General Public
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+ License along with the GNU C Library; if not, see
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+ <http://www.gnu.org/licenses/>. */
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+
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+#ifndef _CET_CONTROL_H
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+#define _CET_CONTROL_H
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+
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+/* For each CET feature, IBT and SHSTK, valid control values. */
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+enum dl_x86_cet_control
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+{
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+ /* Enable CET features based on ELF property note. */
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+ cet_elf_property = 0,
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+ /* Always enable CET features. */
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+ cet_always_on,
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+ /* Always disable CET features. */
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+ cet_always_off,
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+ /* Enable CET features permissively. */
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+ cet_permissive
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+};
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+
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+struct dl_x86_feature_control
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+{
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+ enum dl_x86_cet_control ibt : 2;
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+ enum dl_x86_cet_control shstk : 2;
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+};
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+
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+#endif /* cet-control.h */
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diff --git a/sysdeps/x86/cet-tunables.h b/sysdeps/x86/cet-tunables.h
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deleted file mode 100644
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index ca02305..0000000
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--- a/sysdeps/x86/cet-tunables.h
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+++ /dev/null
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@@ -1,29 +0,0 @@
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-/* x86 CET tuning.
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- This file is part of the GNU C Library.
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- Copyright (C) 2018 Free Software Foundation, Inc.
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-
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- The GNU C Library is free software; you can redistribute it and/or
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- modify it under the terms of the GNU Lesser General Public
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- License as published by the Free Software Foundation; either
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- version 2.1 of the License, or (at your option) any later version.
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-
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- The GNU C Library is distributed in the hope that it will be useful,
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- but WITHOUT ANY WARRANTY; without even the implied warranty of
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- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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- Lesser General Public License for more details.
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-
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- You should have received a copy of the GNU Lesser General Public
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- License along with the GNU C Library; if not, see
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- <http://www.gnu.org/licenses/>. */
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-
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-/* Valid control values:
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- 0: Enable CET features based on ELF property note.
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- 1: Always disable CET features.
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- 2: Always enable CET features.
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- 3: Enable CET features permissively.
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- */
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-#define CET_ELF_PROPERTY 0
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-#define CET_ALWAYS_OFF 1
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-#define CET_ALWAYS_ON 2
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-#define CET_PERMISSIVE 3
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-#define CET_MAX CET_PERMISSIVE
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diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
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index 4695ac8..ac74f40 100644
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--- a/sysdeps/x86/cpu-features.c
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+++ b/sysdeps/x86/cpu-features.c
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@@ -39,7 +39,6 @@ extern void TUNABLE_CALLBACK (set_x86_shstk) (tunable_val_t *)
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#if CET_ENABLED
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# include <dl-cet.h>
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-# include <cet-tunables.h>
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#endif
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static void
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@@ -490,7 +489,7 @@ no_cpuid:
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if (cet_status)
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{
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- GL(dl_x86_feature_1)[0] = cet_status;
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+ GL(dl_x86_feature_1) = cet_status;
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# ifndef SHARED
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/* Check if IBT and SHSTK are enabled by kernel. */
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@@ -514,14 +513,13 @@ no_cpuid:
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/* Clear the disabled bits in dl_x86_feature_1. */
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if (res == 0)
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- GL(dl_x86_feature_1)[0] &= ~cet_feature;
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+ GL(dl_x86_feature_1) &= ~cet_feature;
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}
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/* Lock CET if IBT or SHSTK is enabled in executable. Don't
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- lock CET if SHSTK is enabled permissively. */
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- if (((GL(dl_x86_feature_1)[1] >> CET_MAX)
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- & ((1 << CET_MAX) - 1))
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- != CET_PERMISSIVE)
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+ lock CET if IBT or SHSTK is enabled permissively. */
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+ if (GL(dl_x86_feature_control).ibt != cet_permissive
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+ && GL(dl_x86_feature_control).shstk != cet_permissive)
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dl_cet_lock_cet ();
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}
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# endif
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diff --git a/sysdeps/x86/cpu-tunables.c b/sysdeps/x86/cpu-tunables.c
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index 69155a8..fad6726 100644
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--- a/sysdeps/x86/cpu-tunables.c
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+++ b/sysdeps/x86/cpu-tunables.c
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@@ -336,28 +336,18 @@ TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp)
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}
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# if CET_ENABLED
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-# include <cet-tunables.h>
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attribute_hidden
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void
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TUNABLE_CALLBACK (set_x86_ibt) (tunable_val_t *valp)
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{
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if (DEFAULT_MEMCMP (valp->strval, "on", sizeof ("on")) == 0)
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- {
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- GL(dl_x86_feature_1)[1] &= ~((1 << CET_MAX) - 1);
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- GL(dl_x86_feature_1)[1] |= CET_ALWAYS_ON;
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- }
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+ GL(dl_x86_feature_control).ibt = cet_always_on;
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else if (DEFAULT_MEMCMP (valp->strval, "off", sizeof ("off")) == 0)
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- {
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- GL(dl_x86_feature_1)[1] &= ~((1 << CET_MAX) - 1);
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- GL(dl_x86_feature_1)[1] |= CET_ALWAYS_OFF;
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- }
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+ GL(dl_x86_feature_control).ibt = cet_always_off;
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else if (DEFAULT_MEMCMP (valp->strval, "permissive",
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sizeof ("permissive")) == 0)
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- {
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- GL(dl_x86_feature_1)[1] &= ~((1 << CET_MAX) - 1);
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- GL(dl_x86_feature_1)[1] |= CET_PERMISSIVE;
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- }
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+ GL(dl_x86_feature_control).ibt = cet_permissive;
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}
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attribute_hidden
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@@ -365,21 +355,12 @@ void
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TUNABLE_CALLBACK (set_x86_shstk) (tunable_val_t *valp)
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{
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if (DEFAULT_MEMCMP (valp->strval, "on", sizeof ("on")) == 0)
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- {
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- GL(dl_x86_feature_1)[1] &= ~(((1 << CET_MAX) - 1) << CET_MAX);
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- GL(dl_x86_feature_1)[1] |= (CET_ALWAYS_ON << CET_MAX);
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- }
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+ GL(dl_x86_feature_control).shstk = cet_always_on;
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else if (DEFAULT_MEMCMP (valp->strval, "off", sizeof ("off")) == 0)
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- {
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- GL(dl_x86_feature_1)[1] &= ~(((1 << CET_MAX) - 1) << CET_MAX);
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- GL(dl_x86_feature_1)[1] |= (CET_ALWAYS_OFF << CET_MAX);
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- }
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+ GL(dl_x86_feature_control).shstk = cet_always_off;
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else if (DEFAULT_MEMCMP (valp->strval, "permissive",
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sizeof ("permissive")) == 0)
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- {
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- GL(dl_x86_feature_1)[1] &= ~(((1 << CET_MAX) - 1) << CET_MAX);
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- GL(dl_x86_feature_1)[1] |= (CET_PERMISSIVE << CET_MAX);
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- }
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+ GL(dl_x86_feature_control).shstk = cet_permissive;
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}
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# endif
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#endif
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diff --git a/sysdeps/x86/dl-cet.c b/sysdeps/x86/dl-cet.c
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index 627d937..ebc0d57 100644
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--- a/sysdeps/x86/dl-cet.c
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+++ b/sysdeps/x86/dl-cet.c
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@@ -20,7 +20,6 @@
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#include <libintl.h>
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#include <ldsodefs.h>
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#include <dl-cet.h>
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-#include <cet-tunables.h>
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/* GNU_PROPERTY_X86_FEATURE_1_IBT and GNU_PROPERTY_X86_FEATURE_1_SHSTK
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are defined in <elf.h>, which are only available for C sources.
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@@ -39,23 +38,23 @@ static void
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dl_cet_check (struct link_map *m, const char *program)
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{
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/* Check how IBT should be enabled. */
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- unsigned int enable_ibt_type
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- = GL(dl_x86_feature_1)[1] & ((1 << CET_MAX) - 1);
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+ enum dl_x86_cet_control enable_ibt_type
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+ = GL(dl_x86_feature_control).ibt;
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/* Check how SHSTK should be enabled. */
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- unsigned int enable_shstk_type
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- = ((GL(dl_x86_feature_1)[1] >> CET_MAX) & ((1 << CET_MAX) - 1));
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+ enum dl_x86_cet_control enable_shstk_type
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+ = GL(dl_x86_feature_control).shstk;
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/* No legacy object check if both IBT and SHSTK are always on. */
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- if (enable_ibt_type == CET_ALWAYS_ON
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- && enable_shstk_type == CET_ALWAYS_ON)
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+ if (enable_ibt_type == cet_always_on
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+ && enable_shstk_type == cet_always_on)
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return;
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/* Check if IBT is enabled by kernel. */
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bool ibt_enabled
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- = (GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_IBT) != 0;
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+ = (GL(dl_x86_feature_1) & GNU_PROPERTY_X86_FEATURE_1_IBT) != 0;
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/* Check if SHSTK is enabled by kernel. */
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bool shstk_enabled
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- = (GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0;
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+ = (GL(dl_x86_feature_1) & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0;
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if (ibt_enabled || shstk_enabled)
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{
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@@ -65,9 +64,9 @@ dl_cet_check (struct link_map *m, const char *program)
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/* Check if IBT and SHSTK are enabled in object. */
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bool enable_ibt = (ibt_enabled
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- && enable_ibt_type != CET_ALWAYS_OFF);
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+ && enable_ibt_type != cet_always_off);
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bool enable_shstk = (shstk_enabled
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- && enable_shstk_type != CET_ALWAYS_OFF);
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+ && enable_shstk_type != cet_always_off);
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if (program)
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{
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/* Enable IBT and SHSTK only if they are enabled in executable.
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@@ -76,10 +75,10 @@ dl_cet_check (struct link_map *m, const char *program)
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GLIBC_TUNABLES=glibc.tune.hwcaps=-IBT,-SHSTK
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*/
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enable_ibt &= (HAS_CPU_FEATURE (IBT)
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- && (enable_ibt_type == CET_ALWAYS_ON
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+ && (enable_ibt_type == cet_always_on
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|| (m->l_cet & lc_ibt) != 0));
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enable_shstk &= (HAS_CPU_FEATURE (SHSTK)
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- && (enable_shstk_type == CET_ALWAYS_ON
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+ && (enable_shstk_type == cet_always_on
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|| (m->l_cet & lc_shstk) != 0));
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}
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@@ -111,7 +110,7 @@ dl_cet_check (struct link_map *m, const char *program)
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/* IBT is enabled only if it is enabled in executable as
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well as all shared objects. */
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- enable_ibt &= (enable_ibt_type == CET_ALWAYS_ON
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+ enable_ibt &= (enable_ibt_type == cet_always_on
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|| (l->l_cet & lc_ibt) != 0);
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if (!found_ibt_legacy && enable_ibt != ibt_enabled)
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{
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@@ -121,7 +120,7 @@ dl_cet_check (struct link_map *m, const char *program)
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/* SHSTK is enabled only if it is enabled in executable as
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well as all shared objects. */
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- enable_shstk &= (enable_shstk_type == CET_ALWAYS_ON
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+ enable_shstk &= (enable_shstk_type == cet_always_on
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|| (l->l_cet & lc_shstk) != 0);
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if (enable_shstk != shstk_enabled)
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{
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@@ -137,7 +136,7 @@ dl_cet_check (struct link_map *m, const char *program)
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{
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if (!program)
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{
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- if (enable_ibt_type != CET_PERMISSIVE)
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+ if (enable_ibt_type != cet_permissive)
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{
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/* When IBT is enabled, we cannot dlopen a shared
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object without IBT. */
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@@ -148,7 +147,7 @@ dl_cet_check (struct link_map *m, const char *program)
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N_("rebuild shared object with IBT support enabled"));
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}
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- if (enable_shstk_type != CET_PERMISSIVE)
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+ if (enable_shstk_type != cet_permissive)
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{
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/* When SHSTK is enabled, we cannot dlopen a shared
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object without SHSTK. */
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@@ -159,8 +158,8 @@ dl_cet_check (struct link_map *m, const char *program)
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N_("rebuild shared object with SHSTK support enabled"));
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}
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- if (enable_ibt_type != CET_PERMISSIVE
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- && enable_shstk_type != CET_PERMISSIVE)
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+ if (enable_ibt_type != cet_permissive
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+ && enable_shstk_type != cet_permissive)
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return;
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}
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@@ -190,7 +189,7 @@ dl_cet_check (struct link_map *m, const char *program)
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}
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/* Clear the disabled bits in dl_x86_feature_1. */
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- GL(dl_x86_feature_1)[0] &= ~cet_feature;
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+ GL(dl_x86_feature_1) &= ~cet_feature;
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cet_feature_changed = true;
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}
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@@ -199,9 +198,9 @@ dl_cet_check (struct link_map *m, const char *program)
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if (program && (ibt_enabled || shstk_enabled))
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{
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if ((!ibt_enabled
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- || enable_ibt_type != CET_PERMISSIVE)
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+ || enable_ibt_type != cet_permissive)
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&& (!shstk_enabled
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- || enable_shstk_type != CET_PERMISSIVE))
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+ || enable_shstk_type != cet_permissive))
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{
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/* Lock CET if IBT or SHSTK is enabled in executable unless
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IBT or SHSTK is enabled permissively. */
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diff --git a/sysdeps/x86/dl-procruntime.c b/sysdeps/x86/dl-procruntime.c
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index 920bfe8..26b2b39 100644
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--- a/sysdeps/x86/dl-procruntime.c
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+++ b/sysdeps/x86/dl-procruntime.c
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@@ -47,7 +47,27 @@
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# if !defined PROCINFO_DECL && defined SHARED
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._dl_x86_feature_1
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# else
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-PROCINFO_CLASS unsigned int _dl_x86_feature_1[2]
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+PROCINFO_CLASS unsigned int _dl_x86_feature_1
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+# endif
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+# ifndef PROCINFO_DECL
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+= 0
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+# endif
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+# if !defined SHARED || defined PROCINFO_DECL
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+;
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+# else
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+,
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+# endif
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+
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+# if !defined PROCINFO_DECL && defined SHARED
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+ ._dl_x86_feature_control
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+# else
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+PROCINFO_CLASS struct dl_x86_feature_control _dl_x86_feature_control
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+# endif
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+# ifndef PROCINFO_DECL
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+= {
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+ .ibt = cet_elf_property,
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+ .shstk = cet_elf_property
|
|
+ }
|
|
# endif
|
|
# if !defined SHARED || defined PROCINFO_DECL
|
|
;
|
|
diff --git a/sysdeps/x86/ldsodefs.h b/sysdeps/x86/ldsodefs.h
|
|
index 0616215..54f6864 100644
|
|
--- a/sysdeps/x86/ldsodefs.h
|
|
+++ b/sysdeps/x86/ldsodefs.h
|
|
@@ -61,6 +61,7 @@ struct La_x32_retval;
|
|
struct La_x86_64_retval *, \
|
|
const char *)
|
|
|
|
+#include <cet-control.h>
|
|
#include_next <ldsodefs.h>
|
|
|
|
#endif
|
|
|