On 04/14/22 at 09:43am, Coiby Xu wrote:
> 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.
>
> Fixes: 278311e417be ("kexec, KEYS: Make use of platform keyring for signature verify")
Will the code in bzImage64_verify_sig generic not being genric cause any
issue? Asking this because I don't get why making code generic need add
'Fixes' tag.
> Cc: kexec@xxxxxxxxxxxxxxxxxxx
> Cc: keyrings@xxxxxxxxxxxxxxx
> Cc: linux-security-module@xxxxxxxxxxxxxxx
> Cc: stable@xxxxxxxxxx
> Reviewed-by: Michal Suchanek <msuchanek@xxxxxxx>
> Signed-off-by: Coiby Xu <coxu@xxxxxxxxxx>
> ---
> 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)
> {
> --
> 2.34.1
>
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