On Mon, Oct 11, 2021 at 08:58:36AM -0500, Eric W. Biederman wrote:
Coiby Xu <coxu@xxxxxxxxxx> writes:
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. Make it generic so both x86_64 and arm64 can
use it.
The naming is problematic.
At a minimum please name the new function kexec_kernel_verify_pe_sig.
AKA what you named it without the "arch_" prefix. A function named with
an "arch_" prefix implies that it has an architecture specific
implementation.
Thanks for bringing up this issue and providing the fix and the explanation.
It looks like arch_kexec_kernel_verify_sig should be killed as well
as it only has one implementation in the generic code. And the code
should always call kexec_image_verify_sig_default. Not that you should
do that but I am pointing it out as it seems that is the bad example you
are copying.
Yes, you are right about it. This is a leftover issue of commit
9ec4ecef0af7790551109283ca039a7c52de343c ("kexec_file,x86,powerpc: factor
out kexec_file_ops functions"),
As arch_kexec_kernel_image_{probe,load}(),
arch_kimage_file_post_load_cleanup() and arch_kexec_kernel_verify_sig()
are almost duplicated among architectures, they can be commonalized with
an architecture-defined kexec_file_ops array. So let's factor them out.
That commit moves the architecture specific implementation of
arch_kexec_kernel_verify_sig to kexec_file_ops->verify_sig. So actually
arch_kexec_kernel_verify_sig should be removed. Then we rename
kexec_image_verify_sig_default to kimage_validate_signature and call
it in kimage_validate_signature directly. I'll include a new patch to do
the clean-up work in v3.
Eric
Signed-off-by: Coiby Xu <coxu@xxxxxxxxxx>
---
arch/x86/kernel/kexec-bzimage64.c | 13 +------------
include/linux/kexec.h | 3 +++
kernel/kexec_file.c | 17 +++++++++++++++++
3 files changed, 21 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..0530275b7aa3 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -106,6 +106,23 @@ int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
{
return kexec_image_verify_sig_default(image, buf, buf_len);
}
+
+#ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION
+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;
+}
+#endif
#endif
/*
--
Best regards,
Coiby
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