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Date:   Thu, 12 May 2022 11:52:09 +0800
From:   Baoquan He <bhe@redhat.com>
To:     Coiby Xu <coxu@redhat.com>
Cc:     kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org,
        Michal Suchanek <msuchanek@suse.de>,
        Dave Young <dyoung@redhat.com>, Will Deacon <will@kernel.org>,
        "Eric W . Biederman" <ebiederm@xmission.com>,
        Mimi Zohar <zohar@linux.ibm.com>, Chun-Yi Lee <jlee@suse.com>,
        keyrings@vger.kernel.org, linux-security-module@vger.kernel.org,
        stable@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>,
        "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" 
        <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v7 2/4] kexec, KEYS: make the code in
 bzImage64_verify_sig generic
Message-ID: <YnyEafqEcSh/wRRN@MiWiFi-R3L-srv>
References: <20220512023402.9913-1-coxu@redhat.com>
 <20220512023402.9913-3-coxu@redhat.com>
 <Ynx1DUvDTL1R4Pj5@MiWiFi-R3L-srv>
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In-Reply-To: <Ynx1DUvDTL1R4Pj5@MiWiFi-R3L-srv>
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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
> > 
>