Hi Greg,

This patch depends on three prerequisites but 5.18-stable tree has two prerequisites backported. So the full list of commit ids should be backported is shown below, 1. c903dae8941d ("kexec, KEYS: make the code in bzImage64_verify_sig generic") 2. 0d519cadf751 ("arm64: kexec_file: use more system keyrings to verify kernel image signature")

$ git checkout -b arm_key_5.18.y stable/linux-5.18.y Updating files: 100% (43489/43489), done. branch 'arm_key_5.18.y' set up to track 'stable/linux-5.18.y'. Switched to a new branch 'arm_key_5.18.y'

$ git cherry-pick c903dae8941d 0d519cadf751 Auto-merging include/linux/kexec.h Auto-merging kernel/kexec_file.c [arm_key_5.18.y f3c9c5542700] kexec, KEYS: make the code in bzImage64_verify_sig generic Date: Thu Jul 14 21:40:25 2022 +0800 3 files changed, 25 insertions(+), 19 deletions(-) [arm_key_5.18.y 532854860941] arm64: kexec_file: use more system keyrings to verify kernel image signature Date: Thu Jul 14 21:40:26 2022 +0800 1 file changed, 1 insertion(+), 10 deletions(-)

On Mon, Aug 15, 2022 at 05:33:04PM +0200, gregkh@linuxfoundation.org wrote:

The patch below does not apply to the 5.18-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 0d519cadf75184a24313568e7f489a7fc9b1be3b Mon Sep 17 00:00:00 2001 From: Coiby Xu coxu@redhat.com Date: Thu, 14 Jul 2022 21:40:26 +0800 Subject: [PATCH] arm64: kexec_file: use more system keyrings to verify kernel image signature

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@vger.kernel.org # 105e10e2cf1c: kexec_file: drop weak attribute from functions Cc: stable@vger.kernel.org # 34d5960af253: kexec: clean up arch_kexec_kernel_verify_sig Cc: stable@vger.kernel.org # 83b7bb2d49ae: kexec, KEYS: make the code in bzImage64_verify_sig generic Acked-by: Baoquan He bhe@redhat.com Cc: kexec@lists.infradead.org Cc: keyrings@vger.kernel.org Cc: linux-security-module@vger.kernel.org Co-developed-by: Michal Suchanek msuchanek@suse.de Signed-off-by: Michal Suchanek msuchanek@suse.de Acked-by: Will Deacon will@kernel.org Signed-off-by: Coiby Xu coxu@redhat.com Signed-off-by: Mimi Zohar zohar@linux.ibm.com

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; }

-#ifdef CONFIG_KEXEC_IMAGE_VERIFY_SIG -static int image_verify_sig(const char *kernel, unsigned long kernel_len) -{

• return verify_pefile_signature(kernel, kernel_len, NULL,

• 		       VERIFYING_KEXEC_PE_SIGNATURE);
  

-} -#endif

const struct kexec_file_ops kexec_image_ops = { .probe = image_probe, .load = image_load, #ifdef CONFIG_KEXEC_IMAGE_VERIFY_SIG

• .verify_sig = image_verify_sig,

• .verify_sig = kexec_kernel_verify_pe_sig,

#endif };