linux-kernel - Re: [PATCH v6 3/4] arm64: kexec_file: use more system keyrings to verify kernel image signature

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Message-ID: <20220418054612.54knzv4gqoxbq57a@Rk>
Date:   Mon, 18 Apr 2022 13:46:12 +0800
From:   Coiby Xu <coxu@...hat.com>
To:     Baoquan He <bhe@...hat.com>
Cc:     kexec@...ts.infradead.org, linux-arm-kernel@...ts.infradead.org,
        Michal Suchanek <msuchanek@...e.de>,
        Dave Young <dyoung@...hat.com>, Will Deacon <will@...nel.org>,
        "Eric W . Biederman" <ebiederm@...ssion.com>,
        Mimi Zohar <zohar@...ux.ibm.com>, Chun-Yi Lee <jlee@...e.com>,
        keyrings@...r.kernel.org, linux-security-module@...r.kernel.org,
        stable@...nel.org, Catalin Marinas <catalin.marinas@....com>,
        James Morse <james.morse@....com>,
        AKASHI Takahiro <takahiro.akashi@...aro.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v6 3/4] arm64: kexec_file: use more system keyrings to
 verify kernel image signature

On Mon, Apr 18, 2022 at 10:14:31AM +0800, Baoquan He wrote:
>On 04/14/22 at 09:43am, Coiby Xu wrote:
>> Currently, a problem faced by arm64 is if a kernel image is signed by a
>> MOK key, loading it via the kexec_file_load() system call would be
>> rejected with the error "Lockdown: kexec: kexec of unsigned images is
>> restricted; see man kernel_lockdown.7".
>>
>> This happens because image_verify_sig uses only the primary keyring that
>> contains only kernel built-in keys to verify the kexec image.
>>
>> This patch allows to verify arm64 kernel image signature using not only
>> .builtin_trusted_keys but also .platform and .secondary_trusted_keys
>> keyring.
>>
>> Fixes: 732b7b93d849 ("arm64: kexec_file: add kernel signature verification support")
>
>Cc stable?

Thanks for the reminder! I've added "Cc stable@...nel.org". But it seems
I should Cc stable@...r.kernel.org instead.

>
>Otherwise, LGTM,
>
>Acked-by: Baoquan He <bhe@...hat.com>
>
>> Cc: kexec@...ts.infradead.org
>> Cc: keyrings@...r.kernel.org
>> Cc: linux-security-module@...r.kernel.org
>> Cc: stable@...nel.org
>> Co-developed-by: Michal Suchanek <msuchanek@...e.de>
>> Signed-off-by: Michal Suchanek <msuchanek@...e.de>
>> Acked-by: Will Deacon <will@...nel.org>
>> Signed-off-by: Coiby Xu <coxu@...hat.com>
>> ---
>>  arch/arm64/kernel/kexec_image.c | 11 +----------
>>  1 file changed, 1 insertion(+), 10 deletions(-)
>>
>> diff --git a/arch/arm64/kernel/kexec_image.c b/arch/arm64/kernel/kexec_image.c
>> index 9ec34690e255..5ed6a585f21f 100644
>> --- a/arch/arm64/kernel/kexec_image.c
>> +++ b/arch/arm64/kernel/kexec_image.c
>> @@ -14,7 +14,6 @@
>>  #include <linux/kexec.h>
>>  #include <linux/pe.h>
>>  #include <linux/string.h>
>> -#include <linux/verification.h>
>>  #include <asm/byteorder.h>
>>  #include <asm/cpufeature.h>
>>  #include <asm/image.h>
>> @@ -130,18 +129,10 @@ static void *image_load(struct kimage *image,
>>  	return NULL;
>>  }
>>
>> -#ifdef CONFIG_KEXEC_IMAGE_VERIFY_SIG
>> -static int image_verify_sig(const char *kernel, unsigned long kernel_len)
>> -{
>> -	return verify_pefile_signature(kernel, kernel_len, NULL,
>> -				       VERIFYING_KEXEC_PE_SIGNATURE);
>> -}
>> -#endif
>> -
>>  const struct kexec_file_ops kexec_image_ops = {
>>  	.probe = image_probe,
>>  	.load = image_load,
>>  #ifdef CONFIG_KEXEC_IMAGE_VERIFY_SIG
>> -	.verify_sig = image_verify_sig,
>> +	.verify_sig = kexec_kernel_verify_pe_sig,
>>  #endif
>>  };
>> --
>> 2.34.1
>>
>>
>

-- 
Best regards,
Coiby