Re: [PATCH v20 4/5] fpga: m10bmc-sec: expose max10 canceled keys in sysfs

[Russ Weight <russell.h.weight@intel.com>]

On 5/16/22 21:24, Xu Yilun wrote:
> On Mon, May 16, 2022 at 04:49:40PM -0700, Russ Weight wrote:
>> Extend the MAX10 BMC Secure Update driver to provide sysfs files to
>> expose the 128 bit code signing key (CSK) cancellation vectors. These use
>> the standard bitmap list format (e.g. 1,2-6,9).
>>
>> Each CSK is assigned an ID, a number between 0-127, during the signing
>> process. CSK ID cancellation information is stored in 128-bit fields in
>> write-once locations in flash.  The cancellation of a CSK can be used
>> to prevent the card from being rolled back to older images that were
>> signed with a CSK that is now cancelled.
>>
>> Signed-off-by: Russ Weight <russell.h.weight@intel.com>
>> Reviewed-by: Tom Rix <trix@redhat.com>
>> ---
>> v20:
>>   - Added text to the commit message to further describe the cancellation of
>>     code signing keys.
>> v19:
>>   - Change "card bmc" naming back to "m10 bmc" naming to be consistent
>>     with the parent driver.
>> v18:
>>   - No change
>> v17:
>>   - Update the Date and KernelVersion for the ABI documentation to Jul 2022
>>     and 5.19 respectively.
>>   - Change "m10bmc" in symbol names to "cardbmc" to reflect the fact that the
>>     future devices will not necessarily use the MAX10.
>> v16:
>>   - No Change
>> v15:
>>   - Updated the Dates and KernelVersions in the ABI documentation
>> v14:
>>   - No changes
>> v13:
>>   - Updated ABI documentation date and kernel version
>> v12:
>>   - Updated Date and KernelVersion fields in ABI documentation
>> v11:
>>   - No change
>> v10:
>>   - Changed the path expressions in the sysfs documentation to
>>     replace the n3000 reference with something more generic to
>>     accomodate other devices that use the same driver.
>> v9:
>>   - Rebased to 5.12-rc2 next
>>   - Updated Date and KernelVersion in ABI documentation
>> v8:
>>   - Previously patch 4/6, otherwise no change
>> v7:
>>   - Updated Date and KernelVersion in ABI documentation
>> v6:
>>   - Added WARN_ON() call for (size / stride) to ensure
>>     that the proper count is passed to regmap_bulk_read().
>> v5:
>>   - No change
>> v4:
>>   - Moved sysfs files for displaying the code-signing-key (CSK)
>>     cancellation vectors from the FPGA Security Manger class driver
>>     to here. The m10bmc_csk_vector() and m10bmc_csk_cancel_nbits()
>>     functions are removed and the functionality from these functions
>>     is moved into a show_canceled_csk() function for for displaying
>>     the CSK vectors.
>>   - Added ABI documentation for new sysfs entries
>> v3:
>>   - Changed: iops -> sops, imgr -> smgr, IFPGA_ -> FPGA_, ifpga_ to fpga_
>>   - Changed "MAX10 BMC Secure Engine driver" to "MAX10 BMC Secure Update
>>     driver"
>>   - Removed wrapper functions (m10bmc_raw_*, m10bmc_sys_*). The
>>     underlying functions are now called directly.
>>   - Renamed get_csk_vector() to m10bmc_csk_vector()
>> v2:
>>   - Replaced small function-creation macros for explicit function
>>     declarations.
>>   - Fixed get_csk_vector() function to properly apply the stride
>>     variable in calls to m10bmc_raw_bulk_read()
>>   - Added m10bmc_ prefix to functions in m10bmc_iops structure
>> ---
>>  .../sysfs-driver-intel-m10-bmc-sec-update     | 24 ++++++++++
>>  drivers/fpga/intel-m10-bmc-sec-update.c       | 48 +++++++++++++++++++
>>  2 files changed, 72 insertions(+)
>>
>> diff --git a/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-sec-update b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-sec-update
>> index 1132e39b2125..ca5a34c1c31f 100644
>> --- a/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-sec-update
>> +++ b/Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-sec-update
>> @@ -28,6 +28,30 @@ Description:	Read only. Returns the root entry hash for the BMC image
>>  		underlying device supports it.
>>  		Format: string.
>>  
>> +What:		/sys/bus/platform/drivers/intel-m10bmc-sec-update/.../security/sr_canceled_csks
>> +Date:		Jul 2022
>> +KernelVersion:	5.19
>> +Contact:	Russ Weight <russell.h.weight@intel.com>
>> +Description:	Read only. Returns a list of indices for canceled code
>> +		signing keys for the static region. The standard bitmap
>> +		list format is used (e.g. "1,2-6,9").
>> +
>> +What:		/sys/bus/platform/drivers/intel-m10bmc-sec-update/.../security/pr_canceled_csks
>> +Date:		Jul 2022
>> +KernelVersion:	5.19
>> +Contact:	Russ Weight <russell.h.weight@intel.com>
>> +Description:	Read only. Returns a list of indices for canceled code
>> +		signing keys for the partial reconfiguration region. The
>> +		standard bitmap list format is used (e.g. "1,2-6,9").
>> +
>> +What:		/sys/bus/platform/drivers/intel-m10bmc-sec-update/.../security/bmc_canceled_csks
>> +Date:		Jul 2022
>> +KernelVersion:	5.19
>> +Contact:	Russ Weight <russell.h.weight@intel.com>
>> +Description:	Read only. Returns a list of indices for canceled code
>> +		signing keys for the BMC.  The standard bitmap list format
>> +		is used (e.g. "1,2-6,9").
>> +
>>  What:		/sys/bus/platform/drivers/intel-m10bmc-sec-update/.../security/flash_count
>>  Date:		Jul 2022
>>  KernelVersion:	5.19
>> diff --git a/drivers/fpga/intel-m10-bmc-sec-update.c b/drivers/fpga/intel-m10-bmc-sec-update.c
>> index 3f183202de3b..6c39adc6492d 100644
>> --- a/drivers/fpga/intel-m10-bmc-sec-update.c
>> +++ b/drivers/fpga/intel-m10-bmc-sec-update.c
>> @@ -78,6 +78,51 @@ DEVICE_ATTR_SEC_REH_RO(bmc, BMC_PROG_MAGIC, BMC_PROG_ADDR, BMC_REH_ADDR);
>>  DEVICE_ATTR_SEC_REH_RO(sr, SR_PROG_MAGIC, SR_PROG_ADDR, SR_REH_ADDR);
>>  DEVICE_ATTR_SEC_REH_RO(pr, PR_PROG_MAGIC, PR_PROG_ADDR, PR_REH_ADDR);
>>  
>> +#define CSK_BIT_LEN		128U
>> +#define CSK_32ARRAY_SIZE	DIV_ROUND_UP(CSK_BIT_LEN, 32)
>> +
>> +static ssize_t
>> +show_canceled_csk(struct device *dev, u32 addr, char *buf)
>> +{
>> +	unsigned int i, stride, size = CSK_32ARRAY_SIZE * sizeof(u32);
>> +	struct m10bmc_sec *sec = dev_get_drvdata(dev);
>> +	DECLARE_BITMAP(csk_map, CSK_BIT_LEN);
>> +	__le32 csk_le32[CSK_32ARRAY_SIZE];
>> +	u32 csk32[CSK_32ARRAY_SIZE];
>> +	int ret;
>> +
>> +	stride = regmap_get_reg_stride(sec->m10bmc->regmap);
>> +
>> +	WARN_ON(size % stride);
> Same concern.

OK - I'll handle it as an error case.

Thanks,
- Russ

>
>> +	ret = regmap_bulk_read(sec->m10bmc->regmap, addr, csk_le32,
>> +			       size / stride);
>> +	if (ret) {
>> +		dev_err(sec->dev, "failed to read CSK vector: %x cnt %x: %d\n",
>> +			addr, size / stride, ret);
>> +		return ret;
>> +	}
>> +
>> +	for (i = 0; i < CSK_32ARRAY_SIZE; i++)
>> +		csk32[i] = le32_to_cpu(((csk_le32[i])));
>> +
>> +	bitmap_from_arr32(csk_map, csk32, CSK_BIT_LEN);
>> +	bitmap_complement(csk_map, csk_map, CSK_BIT_LEN);
>> +	return bitmap_print_to_pagebuf(1, buf, csk_map, CSK_BIT_LEN);
>> +}
>> +
>> +#define DEVICE_ATTR_SEC_CSK_RO(_name, _addr) \
>> +static ssize_t _name##_canceled_csks_show(struct device *dev, \
>> +					  struct device_attribute *attr, \
>> +					  char *buf) \
>> +{ return show_canceled_csk(dev, _addr, buf); } \
>> +static DEVICE_ATTR_RO(_name##_canceled_csks)
>> +
>> +#define CSK_VEC_OFFSET 0x34
>> +
>> +DEVICE_ATTR_SEC_CSK_RO(bmc, BMC_PROG_ADDR + CSK_VEC_OFFSET);
>> +DEVICE_ATTR_SEC_CSK_RO(sr, SR_PROG_ADDR + CSK_VEC_OFFSET);
>> +DEVICE_ATTR_SEC_CSK_RO(pr, PR_PROG_ADDR + CSK_VEC_OFFSET);
>> +
>>  #define FLASH_COUNT_SIZE 4096	/* count stored as inverted bit vector */
>>  
>>  static ssize_t flash_count_show(struct device *dev,
>> @@ -118,6 +163,9 @@ static struct attribute *m10bmc_security_attrs[] = {
>>  	&dev_attr_bmc_root_entry_hash.attr,
>>  	&dev_attr_sr_root_entry_hash.attr,
>>  	&dev_attr_pr_root_entry_hash.attr,
>> +	&dev_attr_sr_canceled_csks.attr,
>> +	&dev_attr_pr_canceled_csks.attr,
>> +	&dev_attr_bmc_canceled_csks.attr,
>>  	NULL,
>>  };
>>  
>> -- 
>> 2.25.1