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tpm: Keep the active PCRs in the chip private data

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We have a lot of code trying to reason about the active TPM PCRs
when creating an EventLog. Since changing the active banks can't
be done on the fly and requires a TPM reset,  let's store them
in the chip private data instead.

Upcoming patches will use this during the EventLog creation.

Signed-off-by: Raymond Mao <raymond.mao@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
This commit is contained in:
Ilias Apalodimas
2024-12-24 08:01:09 -08:00
parent 8dc886ce31
commit ffdbf775e7
3 changed files with 42 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
include/tpm-common.h
View File

@@ -42,12 +42,22 @@ enum tpm_version {
TPM_V2,
};
/*
* We deviate from this draft of the specification by increasing the value of
* TPM2_NUM_PCR_BANKS from 3 to 16 to ensure compatibility with TPM2
* implementations that have enabled a larger than typical number of PCR
* banks. This larger value for TPM2_NUM_PCR_BANKS is expected to be included
* in a future revision of the specification.
*/
#define TPM2_NUM_PCR_BANKS 16
/**
* struct tpm_chip_priv - Information about a TPM, stored by the uclass
*
* These values must be set up by the device's probe() method before
* Some of hese values must be set up by the device's probe() method before
* communcation is attempted. If the device has an xfer() method, this is
* not needed. There is no need to set up @buf.
* The active_banks is only valid for TPMv2 after the device is initialized.
*
* @version: TPM stack to be used
* @duration_ms: Length of each duration type in milliseconds
@@ -55,6 +65,8 @@ enum tpm_version {
* @buf: Buffer used during the exchanges with the chip
* @pcr_count: Number of PCR per bank
* @pcr_select_min: Minimum size in bytes of the pcrSelect array
* @active_bank_count: Number of active PCR banks
* @active_banks: Array of active PCRs
* @plat_hier_disabled: Platform hierarchy has been disabled (TPM is locked
* down until next reboot)
*/
@@ -68,6 +80,10 @@ struct tpm_chip_priv {
/* TPM v2 specific data */
uint pcr_count;
uint pcr_select_min;
#if IS_ENABLED(CONFIG_TPM_V2)
u8 active_bank_count;
u32 active_banks[TPM2_NUM_PCR_BANKS];
#endif
bool plat_hier_disabled;
};

10
include/tpm-v2.h
View File

@@ -34,16 +34,6 @@ struct udevice;
#define TPM2_HDR_LEN 10
/*
* We deviate from this draft of the specification by increasing the value of
* TPM2_NUM_PCR_BANKS from 3 to 16 to ensure compatibility with TPM2
* implementations that have enabled a larger than typical number of PCR
* banks. This larger value for TPM2_NUM_PCR_BANKS is expected to be included
* in a future revision of the specification.
*/
#define TPM2_NUM_PCR_BANKS 16
/* Definition of (UINT32) TPM2_CAP Constants */
#define TPM2_CAP_PCRS 0x00000005U
#define TPM2_CAP_TPM_PROPERTIES 0x00000006U

27
lib/tpm-v2.c
View File

@@ -23,6 +23,27 @@
#include "tpm-utils.h"
static int tpm2_update_active_banks(struct udevice *dev)
{
struct tpm_chip_priv *priv = dev_get_uclass_priv(dev);
struct tpml_pcr_selection pcrs;
int ret, i;
ret = tpm2_get_pcr_info(dev, &pcrs);
if (ret)
return ret;
priv->active_bank_count = 0;
for (i = 0; i < pcrs.count; i++) {
if (!tpm2_is_active_bank(&pcrs.selection[i]))
continue;
priv->active_banks[priv->active_bank_count] = pcrs.selection[i].hash;
priv->active_bank_count++;
}
return 0;
}
u32 tpm2_startup(struct udevice *dev, enum tpm2_startup_types mode)
{
const u8 command_v2[12] = {
@@ -41,7 +62,7 @@ u32 tpm2_startup(struct udevice *dev, enum tpm2_startup_types mode)
if (ret && ret != TPM2_RC_INITIALIZE)
return ret;
return 0;
return tpm2_update_active_banks(dev);
}
u32 tpm2_self_test(struct udevice *dev, enum tpm2_yes_no full_test)
@@ -69,8 +90,10 @@ u32 tpm2_auto_start(struct udevice *dev)
rc = tpm2_self_test(dev, TPMI_YES);
}
if (rc)
return rc;
return rc;
return tpm2_update_active_banks(dev);
}
u32 tpm2_clear(struct udevice *dev, u32 handle, const char *pw,