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

Baoquan He
2022-05-12T06:23:10Z

On 05/12/22 at 12:33pm, Coiby Xu wrote:
> On Thu, May 12, 2022 at 11:52:09AM +0800, Baoquan He wrote:
> > 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,
>
> Hi Baoquan,
>
> >
> > 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?
>
> At least it doesn't fix an issue that satisfy the criteria listed in
> https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html

Then it should not be CC-ed to stable.

>
> >
> >
> > > > 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.
>
> Thanks for the suggestion! Shall I send a version to fix this problem or
> can I just bother the maintainer to remove it?

Better send a clean one, it will save maintainer's time, they can pick
it directly.

>
>
> > >
> > > 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
> > > >
> > >
> >
>
> --
> Best regards,
> Coiby
>