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[v26,4/9] x86/cet/ibt: Update ELF header parsing for Indirect Branch Tracking

Message ID 20210427204720.25007-5-yu-cheng.yu@intel.com (mailing list archive)
State New, archived
Headers show
Series Control-flow Enforcement: Indirect Branch Tracking | expand

Commit Message

Yu-cheng Yu April 27, 2021, 8:47 p.m. UTC 
An ELF file's .note.gnu.property indicates features the file supports.
The property is parsed at loading time and passed to arch_setup_elf_
property().  Update it for Indirect Branch Tracking.

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Cc: Kees Cook <keescook@chromium.org>
---
v24:
- Update for changes introduced from splitting shadow stack and ibt.

 arch/x86/Kconfig             | 2 ++
 arch/x86/kernel/process_64.c | 8 ++++++++
 2 files changed, 10 insertions(+)
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Patch

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 6bb69fba0dad..7436e3a608e8 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1970,6 +1970,8 @@  config X86_IBT
 	def_bool n
 	depends on X86_SHADOW_STACK
 	depends on $(cc-option,-fcf-protection)
+	select ARCH_USE_GNU_PROPERTY
+	select ARCH_BINFMT_ELF_STATE
 	help
 	  Indirect Branch Tracking (IBT) provides protection against
 	  CALL-/JMP-oriented programming attacks.  It is active when
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index d71045b29475..bf8ef10e5b78 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -864,6 +864,14 @@  int arch_setup_elf_property(struct arch_elf_state *state)
 			r = shstk_setup();
 	}
 
+	if (r < 0)
+		return r;
+
+	if (cpu_feature_enabled(X86_FEATURE_IBT)) {
+		if (state->gnu_property & GNU_PROPERTY_X86_FEATURE_1_IBT)
+			r = ibt_setup();
+	}
+
 	return r;
 }
 #endif