[PATCH v7 2/4] kexec, KEYS: make the code in bzImage64_verify_sig generic

Coiby Xu
2022-05-12T02:34:20Z

commit 278311e417be ("kexec, KEYS: Make use of platform keyring for
signature verify") adds platform keyring support on x86 kexec but not
arm64.

The code in bzImage64_verify_sig makes 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.

Note this patch is needed by a later patch so Cc it to the stable tree
as well.

Cc: kexec@lists.infradead.org
Cc: keyrings@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Cc: stable@vger.kernel.org # 34d5960af253: kexec: clean up arch_kexec_kernel_verify_sig
Reviewed-by: Michal Suchanek <msuchanek@suse.de>
Signed-off-by: Coiby Xu <coxu@redhat.com>
---
arch/x86/kernel/kexec-bzimage64.c | 20 +-------------------
include/linux/kexec.h | 7 +++++++
kernel/kexec_file.c | 17 +++++++++++++++++
3 files changed, 25 insertions(+), 19 deletions(-)

diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index 170d0fd68b1f..f299b48f9c9f 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>
@@ -528,28 +527,11 @@ static int bzImage64_cleanup(void *loader_data)
return 0;
}

-#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;
-}
-#endif
-
const struct kexec_file_ops kexec_bzImage64_ops = {
.probe = bzImage64_probe,
.load = bzImage64_load,
.cleanup = bzImage64_cleanup,
#ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
- .verify_sig = bzImage64_verify_sig,
+ .verify_sig = kexec_kernel_verify_pe_sig,
#endif
};
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 413235c6c797..da83abfc628b 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>

/* Location of a reserved region to hold the crash kernel.
*/
@@ -202,6 +203,12 @@ 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 3720435807eb..754885b96aab 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)
{
--
2.35.3