diff mbox series

[stable-v6.1,18/18] efi/x86: Fix the missing KASLR_FLAG bit in boot_params->hdr.loadflags

Message ID 20240304111937.2556102-38-ardb+git@google.com
State New
Headers show
Series efistub/x86 changes for secure boot | expand

Commit Message

Ard Biesheuvel March 4, 2024, 11:19 a.m. UTC 
From: Yuntao Wang <ytcoode@gmail.com>

[ Commit 01638431c465741e071ab34acf3bef3c2570f878 upstream ]

When KASLR is enabled, the KASLR_FLAG bit in boot_params->hdr.loadflags
should be set to 1 to propagate KASLR status from compressed kernel to
kernel, just as the choose_random_location() function does.

Currently, when the kernel is booted via the EFI stub, the KASLR_FLAG
bit in boot_params->hdr.loadflags is not set, even though it should be.
This causes some functions, such as kernel_randomize_memory(), not to
execute as expected. Fix it.

Fixes: a1b87d54f4e4 ("x86/efistub: Avoid legacy decompressor when doing EFI boot")
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
[ardb: drop 'else' branch clearing KASLR_FLAG]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/firmware/efi/libstub/x86-stub.c | 2 ++
 1 file changed, 2 insertions(+)
diff mbox series

Patch

diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
index b183b40195ee..a0757a37b482 100644
--- a/drivers/firmware/efi/libstub/x86-stub.c
+++ b/drivers/firmware/efi/libstub/x86-stub.c
@@ -781,6 +781,8 @@  static efi_status_t efi_decompress_kernel(unsigned long *kernel_entry)
 			efi_debug("AMI firmware v2.0 or older detected - disabling physical KASLR\n");
 			seed[0] = 0;
 		}
+
+		boot_params_ptr->hdr.loadflags |= KASLR_FLAG;
 	}
 
 	status = efi_random_alloc(alloc_size, CONFIG_PHYSICAL_ALIGN, &addr,