[PATCH v3 1/3] kexec: clean up arch_kexec_kernel_verify_sig

[PATCH v3 1/3] kexec: clean up arch_kexec_kernel_verify_sig

[Coiby Xu]

commit 9ec4ecef0af7790551109283ca039a7c52de343c ("kexec_file,x86,
powerpc: factor out kexec_file_ops functions" allows implementing
the arch-specific implementation of kernel image verification
in kexec_file_ops->verify_sig. Currently, there is no arch-specific
implementation of arch_kexec_kernel_verify_sig. So clean it up.

Suggested-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Coiby Xu <coxu@redhat.com>
---
 include/linux/kexec.h |  4 ----
 kernel/kexec_file.c   | 34 +++++++++++++---------------------
 2 files changed, 13 insertions(+), 25 deletions(-)

diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 0c994ae37729..755fed183224 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -196,10 +196,6 @@ int arch_kexec_apply_relocations(struct purgatory_info *pi,
 				 const Elf_Shdr *relsec,
 				 const Elf_Shdr *symtab);
 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);
-#endif
 int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf);
 
 extern int kexec_add_buffer(struct kexec_buf *kbuf);
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 33400ff051a8..42b3ac34e4ee 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -89,25 +89,6 @@ int __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
 	return kexec_image_post_load_cleanup_default(image);
 }
 
-#ifdef CONFIG_KEXEC_SIG
-static int kexec_image_verify_sig_default(struct kimage *image, void *buf,
-					  unsigned long buf_len)
-{
-	if (!image->fops || !image->fops->verify_sig) {
-		pr_debug("kernel loader does not support signature verification.\n");
-		return -EKEYREJECTED;
-	}
-
-	return image->fops->verify_sig(buf, buf_len);
-}
-
-int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
-					unsigned long buf_len)
-{
-	return kexec_image_verify_sig_default(image, buf, buf_len);
-}
-#endif
-
 /*
  * arch_kexec_apply_relocations_add - apply relocations of type RELA
  * @pi:		Purgatory to be relocated.
@@ -184,13 +165,24 @@ void kimage_file_post_load_cleanup(struct kimage *image)
 }
 
 #ifdef CONFIG_KEXEC_SIG
+static int kexec_image_verify_sig(struct kimage *image, void *buf,
+		unsigned long buf_len)
+{
+	if (!image->fops || !image->fops->verify_sig) {
+		pr_debug("kernel loader does not support signature verification.\n");
+		return -EKEYREJECTED;
+	}
+
+	return image->fops->verify_sig(buf, buf_len);
+}
+
 static int
 kimage_validate_signature(struct kimage *image)
 {
 	int ret;
 
-	ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf,
-					   image->kernel_buf_len);
+	ret = kexec_image_verify_sig(image, image->kernel_buf,
+			image->kernel_buf_len);
 	if (ret) {
 
 		if (IS_ENABLED(CONFIG_KEXEC_SIG_FORCE)) {
-- 
2.31.1

[PATCH v3 2/3] kexec, KEYS: make the code in bzImage64_verify_sig generic

[Coiby Xu]

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.

Signed-off-by: Coiby Xu <coxu@redhat.com>
---
 arch/x86/kernel/kexec-bzimage64.c | 13 +------------
 include/linux/kexec.h             |  7 +++++++
 kernel/kexec_file.c               | 17 +++++++++++++++++
 3 files changed, 25 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index 170d0fd68b1f..f73aab3fde33 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 kexec_kernel_verify_pe_sig(kernel, kernel_len);
 }
 #endif
 
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 755fed183224..2fe39e946988 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>
@@ -196,6 +197,12 @@ int arch_kexec_apply_relocations(struct purgatory_info *pi,
 				 const Elf_Shdr *relsec,
 				 const Elf_Shdr *symtab);
 int arch_kimage_file_post_load_cleanup(struct kimage *image);
+#ifdef CONFIG_KEXEC_SIG
+#ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION
+int kexec_kernel_verify_pe_sig(const char *kernel,
+				    unsigned long kernel_len);
+#endif
+#endif
 int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf);
 
 extern int kexec_add_buffer(struct kexec_buf *kbuf);
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 42b3ac34e4ee..746d50fd8ebe 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -165,6 +165,23 @@ void kimage_file_post_load_cleanup(struct kimage *image)
 }
 
 #ifdef CONFIG_KEXEC_SIG
+#ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION
+int 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
+
 static int kexec_image_verify_sig(struct kimage *image, void *buf,
 		unsigned long buf_len)
 {
-- 
2.31.1

[PATCH v3 3/3] arm64: kexec_file: use more system keyrings to verify kernel image signature

[Coiby Xu]

This allows to verify arm64 kernel image signature using not only
.builtin_trusted_keys but also .secondary_trusted_keys and .platform keyring.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Coiby Xu <coxu@redhat.com>
---
 arch/arm64/kernel/kexec_image.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/arm64/kernel/kexec_image.c b/arch/arm64/kernel/kexec_image.c
index 9ec34690e255..51af1c22d6da 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>
@@ -133,8 +132,7 @@ static void *image_load(struct kimage *image,
 #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);
+	return kexec_kernel_verify_pe_sig(kernel, kernel_len);
 }
 #endif
 
-- 
2.31.1

Re: [PATCH v3 1/3] kexec: clean up arch_kexec_kernel_verify_sig

[Coiby Xu]

Hi Eric,

Does this patch and "[PATCH v3 2/3] kexec, KEYS: make the code in
bzImage64_verify_sig generic" look good you?

On Mon, Oct 18, 2021 at 04:31:35PM +0800, Coiby Xu wrote:
>commit 9ec4ecef0af7790551109283ca039a7c52de343c ("kexec_file,x86,
>powerpc: factor out kexec_file_ops functions" allows implementing
>the arch-specific implementation of kernel image verification
>in kexec_file_ops->verify_sig. Currently, there is no arch-specific
>implementation of arch_kexec_kernel_verify_sig. So clean it up.
>
>Suggested-by: Eric W. Biederman <ebiederm@xmission.com>
>Signed-off-by: Coiby Xu <coxu@redhat.com>
>---
> include/linux/kexec.h |  4 ----
> kernel/kexec_file.c   | 34 +++++++++++++---------------------
> 2 files changed, 13 insertions(+), 25 deletions(-)
>
>diff --git a/include/linux/kexec.h b/include/linux/kexec.h
>index 0c994ae37729..755fed183224 100644
>--- a/include/linux/kexec.h
>+++ b/include/linux/kexec.h
>@@ -196,10 +196,6 @@ int arch_kexec_apply_relocations(struct purgatory_info *pi,
> 				 const Elf_Shdr *relsec,
> 				 const Elf_Shdr *symtab);
> 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);
>-#endif
> int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf);
>
> extern int kexec_add_buffer(struct kexec_buf *kbuf);
>diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
>index 33400ff051a8..42b3ac34e4ee 100644
>--- a/kernel/kexec_file.c
>+++ b/kernel/kexec_file.c
>@@ -89,25 +89,6 @@ int __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
> 	return kexec_image_post_load_cleanup_default(image);
> }
>
>-#ifdef CONFIG_KEXEC_SIG
>-static int kexec_image_verify_sig_default(struct kimage *image, void *buf,
>-					  unsigned long buf_len)
>-{
>-	if (!image->fops || !image->fops->verify_sig) {
>-		pr_debug("kernel loader does not support signature verification.\n");
>-		return -EKEYREJECTED;
>-	}
>-
>-	return image->fops->verify_sig(buf, buf_len);
>-}
>-
>-int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
>-					unsigned long buf_len)
>-{
>-	return kexec_image_verify_sig_default(image, buf, buf_len);
>-}
>-#endif
>-
> /*
>  * arch_kexec_apply_relocations_add - apply relocations of type RELA
>  * @pi:		Purgatory to be relocated.
>@@ -184,13 +165,24 @@ void kimage_file_post_load_cleanup(struct kimage *image)
> }
>
> #ifdef CONFIG_KEXEC_SIG
>+static int kexec_image_verify_sig(struct kimage *image, void *buf,
>+		unsigned long buf_len)
>+{
>+	if (!image->fops || !image->fops->verify_sig) {
>+		pr_debug("kernel loader does not support signature verification.\n");
>+		return -EKEYREJECTED;
>+	}
>+
>+	return image->fops->verify_sig(buf, buf_len);
>+}
>+
> static int
> kimage_validate_signature(struct kimage *image)
> {
> 	int ret;
>
>-	ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf,
>-					   image->kernel_buf_len);
>+	ret = kexec_image_verify_sig(image, image->kernel_buf,
>+			image->kernel_buf_len);
> 	if (ret) {
>
> 		if (IS_ENABLED(CONFIG_KEXEC_SIG_FORCE)) {
>-- 
>2.31.1
>

-- 
Best regards,
Coiby