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

Baoquan He
2022-05-12T03:52:35Z

On 05/12/22 at 10:46am, Baoquan He wrote:
> On 05/12/22 at 10:34am, 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.
> >
> > Note this patch is needed by a later patch so Cc it to the stable tree
> > as well.
>
> This note should not be added in log.
>
> >
> > 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

Hold on, should we CC stable when it's not fixing an issue?

Hi Coiby,

Just to make clear , is this patch fixing an issue, or it's just an
preparation for later patch's use?

Or I should ask in another way, any problem is solved with this patch?

> > Reviewed-by: Michal Suchanek <msuchanek@suse.de>
> > Signed-off-by: Coiby Xu <coxu@redhat.com>
> > ---
>
> You can put the note here, it won't be added to commit log when merged.
> Maybe it can be removed when merged.
>
> Otherwise, LGTM
>
> Acked-by: Baoquan He <bhe@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
> >
>