On 1/2/24 09:29, Ard Biesheuvel wrote:
On Tue, 26 Dec 2023 at 15:03, Yuntao Wang <ytcoode@xxxxxxxxx> wrote: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 kernel is booted via 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. Signed-off-by: Yuntao Wang <ytcoode@xxxxxxxxx> --- drivers/firmware/efi/libstub/x86-stub.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c index da9b7b8d0716..b0c68593ad40 100644 --- a/drivers/firmware/efi/libstub/x86-stub.c +++ b/drivers/firmware/efi/libstub/x86-stub.c @@ -787,7 +787,10 @@ 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; + } else + boot_params_ptr->hdr.loadflags &= ~KASLR_FLAG;Thanks for the fix.
Does it need a Fixes: tag? Thanks, Tom
I'll queue this up right away, but I am going to drop the 'else' part, given that the KASLR flag is never set by the EFI stub so clearing it should never be needed.status = efi_random_alloc(alloc_size, CONFIG_PHYSICAL_ALIGN, &addr, seed[0], EFI_LOADER_CODE, -- 2.43.0
