Re: [PATCH v19 4/7] x86/cet/ibt: Update ELF header parsing for Indirect Branch Tracking

[Kees Cook]

On Wed, Feb 03, 2021 at 02:58:59PM -0800, Yu-cheng Yu wrote:
> 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 

Reviewed-by: Kees Cook 

-- 
Kees Cook

[PATCH v19 4/7] x86/cet/ibt: Update ELF header parsing for Indirect Branch Tracking

[Yu-cheng Yu]

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 
---
 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