[v4,2/6] tpm: remove definition of TPM2_ACTIVE_PCR_BANKS
diff mbox series

Message ID 20181106150159.1136-3-roberto.sassu@huawei.com
State New
Headers show
Series
  • tpm: retrieve digest size of unknown algorithms from TPM
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Commit Message

Roberto Sassu Nov. 6, 2018, 3:01 p.m. UTC
tcg_efi_specid_event and tcg_pcr_event2 declaration contains static arrays
for a list of hash algorithms used for event logs and event log digests.
However, according to TCG EFI Protocol Specification, these arrays have
variable sizes and are not suitable for parsing events with type casting.

Since declaring static arrays with hard-coded sizes does not help to parse
data after these arrays, this patch removes the declaration of
TPM2_ACTIVE_PCR_BANKS and sets the size of the arrays above to zero.

Fixes: 4d23cc323cdb ("tpm: add securityfs support for TPM 2.0 firmware
event log")

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
 include/linux/tpm_eventlog.h | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

Comments

Jarkko Sakkinen Nov. 8, 2018, 2:02 p.m. UTC | #1
On Tue, Nov 06, 2018 at 04:01:55PM +0100, Roberto Sassu wrote:
> tcg_efi_specid_event and tcg_pcr_event2 declaration contains static arrays
> for a list of hash algorithms used for event logs and event log digests.
> However, according to TCG EFI Protocol Specification, these arrays have
> variable sizes and are not suitable for parsing events with type casting.
> 
> Since declaring static arrays with hard-coded sizes does not help to parse
> data after these arrays, this patch removes the declaration of
> TPM2_ACTIVE_PCR_BANKS and sets the size of the arrays above to zero.
> 
> Fixes: 4d23cc323cdb ("tpm: add securityfs support for TPM 2.0 firmware
> event log")
> 
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> ---
>  include/linux/tpm_eventlog.h | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/include/linux/tpm_eventlog.h b/include/linux/tpm_eventlog.h
> index 20d9da77fc11..3d5d162f09cc 100644
> --- a/include/linux/tpm_eventlog.h
> +++ b/include/linux/tpm_eventlog.h
> @@ -8,7 +8,6 @@
>  #define TCG_EVENT_NAME_LEN_MAX	255
>  #define MAX_TEXT_EVENT		1000	/* Max event string length */
>  #define ACPI_TCPA_SIG		"TCPA"	/* 0x41504354 /'TCPA' */
> -#define TPM2_ACTIVE_PCR_BANKS	3
>  
>  #define EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2 0x1
>  #define EFI_TCG2_EVENT_LOG_FORMAT_TCG_2   0x2
> @@ -90,7 +89,7 @@ struct tcg_efi_specid_event {
>  	u8 spec_errata;
>  	u8 uintnsize;
>  	u32 num_algs;
> -	struct tcg_efi_specid_event_algs digest_sizes[TPM2_ACTIVE_PCR_BANKS];
> +	struct tcg_efi_specid_event_algs digest_sizes[0];
>  	u8 vendor_info_size;
>  	u8 vendor_info[0];
>  } __packed;
> @@ -117,7 +116,7 @@ struct tcg_pcr_event2 {
>  	u32 pcr_idx;
>  	u32 event_type;
>  	u32 count;
> -	struct tpm2_digest digests[TPM2_ACTIVE_PCR_BANKS];
> +	struct tpm2_digest digests[0];
>  	struct tcg_event_field event;

Last two fields make sense at least without comment as they overlap.

>  } __packed;
>  
> -- 
> 2.17.1
> 

/Jarkko
Jarkko Sakkinen Nov. 8, 2018, 2:03 p.m. UTC | #2
On Thu, Nov 08, 2018 at 04:02:08PM +0200, Jarkko Sakkinen wrote:
> On Tue, Nov 06, 2018 at 04:01:55PM +0100, Roberto Sassu wrote:
> > tcg_efi_specid_event and tcg_pcr_event2 declaration contains static arrays
> > for a list of hash algorithms used for event logs and event log digests.
> > However, according to TCG EFI Protocol Specification, these arrays have
> > variable sizes and are not suitable for parsing events with type casting.
> > 
> > Since declaring static arrays with hard-coded sizes does not help to parse
> > data after these arrays, this patch removes the declaration of
> > TPM2_ACTIVE_PCR_BANKS and sets the size of the arrays above to zero.
> > 
> > Fixes: 4d23cc323cdb ("tpm: add securityfs support for TPM 2.0 firmware
> > event log")
> > 
> > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> > ---
> >  include/linux/tpm_eventlog.h | 5 ++---
> >  1 file changed, 2 insertions(+), 3 deletions(-)
> > 
> > diff --git a/include/linux/tpm_eventlog.h b/include/linux/tpm_eventlog.h
> > index 20d9da77fc11..3d5d162f09cc 100644
> > --- a/include/linux/tpm_eventlog.h
> > +++ b/include/linux/tpm_eventlog.h
> > @@ -8,7 +8,6 @@
> >  #define TCG_EVENT_NAME_LEN_MAX	255
> >  #define MAX_TEXT_EVENT		1000	/* Max event string length */
> >  #define ACPI_TCPA_SIG		"TCPA"	/* 0x41504354 /'TCPA' */
> > -#define TPM2_ACTIVE_PCR_BANKS	3
> >  
> >  #define EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2 0x1
> >  #define EFI_TCG2_EVENT_LOG_FORMAT_TCG_2   0x2
> > @@ -90,7 +89,7 @@ struct tcg_efi_specid_event {
> >  	u8 spec_errata;
> >  	u8 uintnsize;
> >  	u32 num_algs;
> > -	struct tcg_efi_specid_event_algs digest_sizes[TPM2_ACTIVE_PCR_BANKS];
> > +	struct tcg_efi_specid_event_algs digest_sizes[0];
> >  	u8 vendor_info_size;
> >  	u8 vendor_info[0];
> >  } __packed;
> > @@ -117,7 +116,7 @@ struct tcg_pcr_event2 {
> >  	u32 pcr_idx;
> >  	u32 event_type;
> >  	u32 count;
> > -	struct tpm2_digest digests[TPM2_ACTIVE_PCR_BANKS];
> > +	struct tpm2_digest digests[0];
> >  	struct tcg_event_field event;
> 
> Last two fields make sense at least without comment as they overlap.

i.e. would be semantically equal to

union {
	struct tpm2_digest digests[0];
	struct tcg_event_field event;
};

/Jarkko
Roberto Sassu Nov. 8, 2018, 2:52 p.m. UTC | #3
On 11/8/2018 3:03 PM, Jarkko Sakkinen wrote:
> On Thu, Nov 08, 2018 at 04:02:08PM +0200, Jarkko Sakkinen wrote:
>> On Tue, Nov 06, 2018 at 04:01:55PM +0100, Roberto Sassu wrote:
>>> tcg_efi_specid_event and tcg_pcr_event2 declaration contains static arrays
>>> for a list of hash algorithms used for event logs and event log digests.
>>> However, according to TCG EFI Protocol Specification, these arrays have
>>> variable sizes and are not suitable for parsing events with type casting.
>>>
>>> Since declaring static arrays with hard-coded sizes does not help to parse
>>> data after these arrays, this patch removes the declaration of
>>> TPM2_ACTIVE_PCR_BANKS and sets the size of the arrays above to zero.
>>>
>>> Fixes: 4d23cc323cdb ("tpm: add securityfs support for TPM 2.0 firmware
>>> event log")
>>>
>>> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
>>> ---
>>>   include/linux/tpm_eventlog.h | 5 ++---
>>>   1 file changed, 2 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/include/linux/tpm_eventlog.h b/include/linux/tpm_eventlog.h
>>> index 20d9da77fc11..3d5d162f09cc 100644
>>> --- a/include/linux/tpm_eventlog.h
>>> +++ b/include/linux/tpm_eventlog.h
>>> @@ -8,7 +8,6 @@
>>>   #define TCG_EVENT_NAME_LEN_MAX	255
>>>   #define MAX_TEXT_EVENT		1000	/* Max event string length */
>>>   #define ACPI_TCPA_SIG		"TCPA"	/* 0x41504354 /'TCPA' */
>>> -#define TPM2_ACTIVE_PCR_BANKS	3
>>>   
>>>   #define EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2 0x1
>>>   #define EFI_TCG2_EVENT_LOG_FORMAT_TCG_2   0x2
>>> @@ -90,7 +89,7 @@ struct tcg_efi_specid_event {
>>>   	u8 spec_errata;
>>>   	u8 uintnsize;
>>>   	u32 num_algs;
>>> -	struct tcg_efi_specid_event_algs digest_sizes[TPM2_ACTIVE_PCR_BANKS];
>>> +	struct tcg_efi_specid_event_algs digest_sizes[0];
>>>   	u8 vendor_info_size;
>>>   	u8 vendor_info[0];
>>>   } __packed;
>>> @@ -117,7 +116,7 @@ struct tcg_pcr_event2 {
>>>   	u32 pcr_idx;
>>>   	u32 event_type;
>>>   	u32 count;
>>> -	struct tpm2_digest digests[TPM2_ACTIVE_PCR_BANKS];
>>> +	struct tpm2_digest digests[0];
>>>   	struct tcg_event_field event;
>>
>> Last two fields make sense at least without comment as they overlap.
> 
> i.e. would be semantically equal to
> 
> union {
> 	struct tpm2_digest digests[0];
> 	struct tcg_event_field event;
> };

I didn't understand. Should I add the union?

Roberto


> /Jarkko
>
Jarkko Sakkinen Nov. 8, 2018, 7:05 p.m. UTC | #4
On Tue, Nov 06, 2018 at 04:01:55PM +0100, Roberto Sassu wrote:
> tcg_efi_specid_event and tcg_pcr_event2 declaration contains static arrays
> for a list of hash algorithms used for event logs and event log digests.
> However, according to TCG EFI Protocol Specification, these arrays have
> variable sizes and are not suitable for parsing events with type casting.
> 
> Since declaring static arrays with hard-coded sizes does not help to parse
> data after these arrays, this patch removes the declaration of
> TPM2_ACTIVE_PCR_BANKS and sets the size of the arrays above to zero.
> 
> Fixes: 4d23cc323cdb ("tpm: add securityfs support for TPM 2.0 firmware
> event log")
> 
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> diff --git a/include/linux/tpm_eventlog.h b/include/linux/tpm_eventlog.h
> index 20d9da77fc11..3d5d162f09cc 100644
> --- a/include/linux/tpm_eventlog.h
> +++ b/include/linux/tpm_eventlog.h
> @@ -8,7 +8,6 @@
>  #define TCG_EVENT_NAME_LEN_MAX	255
>  #define MAX_TEXT_EVENT		1000	/* Max event string length */
>  #define ACPI_TCPA_SIG		"TCPA"	/* 0x41504354 /'TCPA' */
> -#define TPM2_ACTIVE_PCR_BANKS	3
>  
>  #define EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2 0x1
>  #define EFI_TCG2_EVENT_LOG_FORMAT_TCG_2   0x2
> @@ -90,7 +89,7 @@ struct tcg_efi_specid_event {
>  	u8 spec_errata;
>  	u8 uintnsize;
>  	u32 num_algs;
> -	struct tcg_efi_specid_event_algs digest_sizes[TPM2_ACTIVE_PCR_BANKS];
> +	struct tcg_efi_specid_event_algs digest_sizes[0];
>  	u8 vendor_info_size;
>  	u8 vendor_info[0];
>  } __packed;
> @@ -117,7 +116,7 @@ struct tcg_pcr_event2 {
>  	u32 pcr_idx;
>  	u32 event_type;
>  	u32 count;
> -	struct tpm2_digest digests[TPM2_ACTIVE_PCR_BANKS];
> +	struct tpm2_digest digests[0];
>  	struct tcg_event_field event;
>  } __packed;
>  
> -- 
> 2.17.1
> 

I somehow lost your response but what you must do is to explain why is
it OK for last two fields to overlap.

/Jarkko

Patch
diff mbox series

diff --git a/include/linux/tpm_eventlog.h b/include/linux/tpm_eventlog.h
index 20d9da77fc11..3d5d162f09cc 100644
--- a/include/linux/tpm_eventlog.h
+++ b/include/linux/tpm_eventlog.h
@@ -8,7 +8,6 @@ 
 #define TCG_EVENT_NAME_LEN_MAX	255
 #define MAX_TEXT_EVENT		1000	/* Max event string length */
 #define ACPI_TCPA_SIG		"TCPA"	/* 0x41504354 /'TCPA' */
-#define TPM2_ACTIVE_PCR_BANKS	3
 
 #define EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2 0x1
 #define EFI_TCG2_EVENT_LOG_FORMAT_TCG_2   0x2
@@ -90,7 +89,7 @@  struct tcg_efi_specid_event {
 	u8 spec_errata;
 	u8 uintnsize;
 	u32 num_algs;
-	struct tcg_efi_specid_event_algs digest_sizes[TPM2_ACTIVE_PCR_BANKS];
+	struct tcg_efi_specid_event_algs digest_sizes[0];
 	u8 vendor_info_size;
 	u8 vendor_info[0];
 } __packed;
@@ -117,7 +116,7 @@  struct tcg_pcr_event2 {
 	u32 pcr_idx;
 	u32 event_type;
 	u32 count;
-	struct tpm2_digest digests[TPM2_ACTIVE_PCR_BANKS];
+	struct tpm2_digest digests[0];
 	struct tcg_event_field event;
 } __packed;