[PATCH v10 3/4] arm64: kexec_file: use more system keyrings to verify kernel image signature

From: Coiby Xu
Date: Thu Jul 14 2022 - 09:41:28 EST

Currently, when loading a kernel image via the kexec_file_load() system
call, arm64 can only use the .builtin_trusted_keys keyring to verify
a signature whereas x86 can use three more keyrings i.e.
.secondary_trusted_keys, .machine and .platform keyrings. For example,
one resulting problem is kexec'ing a kernel image would be rejected
with the error "Lockdown: kexec: kexec of unsigned images is restricted;
see man kernel_lockdown.7".

This patch set enables arm64 to make use of the same keyrings as x86 to
verify the signature kexec'ed kernel image.

Fixes: 732b7b93d849 ("arm64: kexec_file: add kernel signature verification support")
Cc: stable@xxxxxxxxxxxxxxx # 105e10e2cf1c: kexec_file: drop weak attribute from functions
Cc: stable@xxxxxxxxxxxxxxx # 34d5960af253: kexec: clean up arch_kexec_kernel_verify_sig
Cc: stable@xxxxxxxxxxxxxxx # 83b7bb2d49ae: kexec, KEYS: make the code in bzImage64_verify_sig generic
Acked-by: Baoquan He <bhe@xxxxxxxxxx>
Cc: kexec@xxxxxxxxxxxxxxxxxxx
Cc: keyrings@xxxxxxxxxxxxxxx
Cc: linux-security-module@xxxxxxxxxxxxxxx
Co-developed-by: Michal Suchanek <msuchanek@xxxxxxx>
Signed-off-by: Michal Suchanek <msuchanek@xxxxxxx>
Acked-by: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Coiby Xu <coxu@xxxxxxxxxx>
arch/arm64/kernel/kexec_image.c | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/arch/arm64/kernel/kexec_image.c b/arch/arm64/kernel/kexec_image.c
index 9ec34690e255..5ed6a585f21f 100644
--- a/arch/arm64/kernel/kexec_image.c
+++ b/arch/arm64/kernel/kexec_image.c
@@ -14,7 +14,6 @@
#include <linux/kexec.h>
#include <linux/pe.h>
#include <linux/string.h>
-#include <linux/verification.h>
#include <asm/byteorder.h>
#include <asm/cpufeature.h>
#include <asm/image.h>
@@ -130,18 +129,10 @@ static void *image_load(struct kimage *image,
return NULL;

-static int image_verify_sig(const char *kernel, unsigned long kernel_len)
- return verify_pefile_signature(kernel, kernel_len, NULL,
const struct kexec_file_ops kexec_image_ops = {
.probe = image_probe,
.load = image_load,
- .verify_sig = image_verify_sig,
+ .verify_sig = kexec_kernel_verify_pe_sig,