2022-04-14 14:22:33

by Coiby Xu

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

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: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Co-developed-by: Michal Suchanek <[email protected]>
Signed-off-by: Michal Suchanek <[email protected]>
Acked-by: Will Deacon <[email protected]>
Signed-off-by: Coiby Xu <[email protected]>
---
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

2022-04-18 06:58:57

by Baoquan He

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

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?

Otherwise, LGTM,

Acked-by: Baoquan He <[email protected]>

> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Co-developed-by: Michal Suchanek <[email protected]>
> Signed-off-by: Michal Suchanek <[email protected]>
> Acked-by: Will Deacon <[email protected]>
> Signed-off-by: Coiby Xu <[email protected]>
> ---
> 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
>
>

2022-04-18 12:38:21

by Coiby Xu

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 [email protected]". But it seems
I should Cc [email protected] instead.

>
>Otherwise, LGTM,
>
>Acked-by: Baoquan He <[email protected]>
>
>> Cc: [email protected]
>> Cc: [email protected]
>> Cc: [email protected]
>> Cc: [email protected]
>> Co-developed-by: Michal Suchanek <[email protected]>
>> Signed-off-by: Michal Suchanek <[email protected]>
>> Acked-by: Will Deacon <[email protected]>
>> Signed-off-by: Coiby Xu <[email protected]>
>> ---
>> 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