[PATCH v8 05/14] x86/cet/ibt: ELF header parsing for IBT

Yu-cheng Yu
2019-08-13T21:04:39Z

Look in .note.gnu.property of an ELF file and check if Indirect
Branch Tracking needs to be enabled for the task.

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
---
arch/x86/Kconfig | 1 +
arch/x86/kernel/process_64.c | 5 +++++
2 files changed, 6 insertions(+)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 666dc66a382e..7edb544cef00 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1971,6 +1971,7 @@ config X86_INTEL_BRANCH_TRACKING_USER
select X86_INTEL_CET
select ARCH_HAS_AS_LIMIT
select ARCH_USE_GNU_PROPERTY
+ select ARCH_BINFMT_ELF_STATE
---help---
Indirect Branch Tracking provides hardware protection against return-/jmp-
oriented programming attacks.
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 7ec60b14e96d..a051cfc5242f 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -856,6 +856,11 @@ int arch_setup_property(struct arch_elf_state *state)
return r;
}

+ if (cpu_feature_enabled(X86_FEATURE_IBT)) {
+ if (state->gnu_property & GNU_PROPERTY_X86_FEATURE_1_IBT)
+ r = cet_setup_ibt();
+ }
+
return r;
}
#endif
--
2.17.1