[PATCH v12 4/8] x86/cet/ibt: ELF header parsing for Indirect Branch Tracking

From: Yu-cheng Yu
Date: Fri Sep 18 2020 - 15:24:28 EST


Update arch_setup_elf_property() for Indirect Branch Tracking.

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx>
---
v9:
- Change cpu_feature_enabled() to static_cpu_has().

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

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index b047e0a8d1c2..5bd6d6a10047 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1969,6 +1969,8 @@ config X86_INTEL_BRANCH_TRACKING_USER
depends on CPU_SUP_INTEL && X86_64
depends on $(cc-option,-fcf-protection)
select X86_INTEL_CET
+ 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 fd4644865a3b..c084e1a37d11 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -866,6 +866,14 @@ int arch_setup_elf_property(struct arch_elf_state *state)
r = cet_setup_shstk();
}

+ if (r < 0)
+ return r;
+
+ if (static_cpu_has(X86_FEATURE_IBT)) {
+ if (state->gnu_property & GNU_PROPERTY_X86_FEATURE_1_IBT)
+ r = cet_setup_ibt();
+ }
+
return r;
}
#endif
--
2.21.0