Re: [PATCH 1/2] kexec, KEYS: make the code in bzImage64_verify_sig public
From: Coiby Xu
Date: Thu Oct 07 2021 - 21:15:49 EST
Hi Dave,
On Thu, Sep 30, 2021 at 08:49:02PM +0800, Dave Young wrote:
Hi Coiby,
On 09/27/21 at 08:50am, Coiby Xu wrote:
From: Coiby Xu <coxu@xxxxxxxxxx>
The code in bzImage64_verify_sig could make use of system keyrings including
.buitin_trusted_keys, .secondary_trusted_keys and .platform keyring to verify
signed kernel image as PE file. Move it to a public function.
Signed-off-by: Coiby Xu <coiby.xu@xxxxxxxxx>
---
arch/x86/kernel/kexec-bzimage64.c | 13 +------------
include/linux/kexec.h | 3 +++
kernel/kexec_file.c | 15 +++++++++++++++
3 files changed, 19 insertions(+), 12 deletions(-)
diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index 170d0fd68b1f..4136dd3be5a9 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -17,7 +17,6 @@
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/efi.h>
-#include <linux/verification.h>
#include <asm/bootparam.h>
#include <asm/setup.h>
@@ -531,17 +530,7 @@ static int bzImage64_cleanup(void *loader_data)
#ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
static int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len)
{
- int ret;
-
- ret = verify_pefile_signature(kernel, kernel_len,
- VERIFY_USE_SECONDARY_KEYRING,
- VERIFYING_KEXEC_PE_SIGNATURE);
- if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) {
- ret = verify_pefile_signature(kernel, kernel_len,
- VERIFY_USE_PLATFORM_KEYRING,
- VERIFYING_KEXEC_PE_SIGNATURE);
- }
- return ret;
+ return arch_kexec_kernel_verify_pe_sig(kernel, kernel_len);
}
#endif
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 0c994ae37729..d45f32336dbe 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -19,6 +19,7 @@
#include <asm/io.h>
#include <uapi/linux/kexec.h>
+#include <linux/verification.h>
#ifdef CONFIG_KEXEC_CORE
#include <linux/list.h>
@@ -199,6 +200,8 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image);
#ifdef CONFIG_KEXEC_SIG
int arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
unsigned long buf_len);
+int arch_kexec_kernel_verify_pe_sig(const char *kernel,
+ unsigned long kernel_len);
#endif
int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf);
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 33400ff051a8..85ed6984ad8f 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -106,6 +106,21 @@ int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
{
return kexec_image_verify_sig_default(image, buf, buf_len);
}
+
+int arch_kexec_kernel_verify_pe_sig(const char *kernel, unsigned long kernel_len)
+{
+ int ret;
+
+ ret = verify_pefile_signature(kernel, kernel_len,
+ VERIFY_USE_SECONDARY_KEYRING,
+ VERIFYING_KEXEC_PE_SIGNATURE);
+ if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) {
+ ret = verify_pefile_signature(kernel, kernel_len,
+ VERIFY_USE_PLATFORM_KEYRING,
+ VERIFYING_KEXEC_PE_SIGNATURE);
+ }
+ return ret;
+}
Since the function is moved as generic code, the kconfig option
CONFIG_KEXEC_BZIMAGE_VERIFY_SIG can be removed.
Instead a CONFIG_KEXEC_PEFILE_VERIFY_SIG can be added so that it does
not need to be compiled for only platform which support UEFI pefile
signature verification. And the related arch kexec_file kconfig can
just select it.
Thanks for the suggestion! I notice KEXEC_BZIMAGE_VERIFY_SIG depends
on SIGNED_PE_FILE_VERIFICATION and selects SYSTEM_TRUSTED_KEYRING. So
maybe SIGNED_PE_FILE_VERIFICATION could do the job of
CONFIG_KEXEC_PEFILE_VERIFY_SIG. And arch/arm64/Kconfig also have
KEXEC_IMAGE_VERIFY_SIG. So maybe it's better we don't keep
CONFIG_KEXEC_BZIMAGE_VERIFY_SIG.
Coiby, can you try above?
#endif
/*
--
2.33.0
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Thanks
Dave
--
Best regards,
Coiby