[PATCH v21 4/7] x86/cet/ibt: Update ELF header parsing for Indirect Branch Tracking

From: Yu-cheng Yu
Date: Wed Feb 17 2021 - 17:46:07 EST


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@xxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
arch/x86/kernel/process_64.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 19f138f7a209..ccf3f66f4d2c 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 = 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