From 1db15344f874f656b267a79467d1e7ee6442ba09 Mon Sep 17 00:00:00 2001 From: Nayna Jain Date: Mon, 30 Jan 2017 04:59:40 -0500 Subject: [PATCH] tpm: implement TPM 2.0 capability to get active PCR banks This patch implements the TPM 2.0 capability TPM_CAP_PCRS to retrieve the active PCR banks from the TPM. This is needed to enable extending all active banks as recommended by TPM 2.0 TCG Specification. Signed-off-by: Nayna Jain Reviewed-by: Jarkko Sakkinen Tested-by: Jarkko Sakkinen Tested-by: Kenneth Goldman Signed-off-by: Jarkko Sakkinen --- drivers/char/tpm/tpm.h | 5 +++ drivers/char/tpm/tpm2-cmd.c | 77 +++++++++++++++++++++++++++++++++++++ 2 files changed, 82 insertions(+) diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h index dbe0c5a72c67..db0398a4e3e5 100644 --- a/drivers/char/tpm/tpm.h +++ b/drivers/char/tpm/tpm.h @@ -97,6 +97,7 @@ enum tpm2_return_codes { }; enum tpm2_algorithms { + TPM2_ALG_ERROR = 0x0000, TPM2_ALG_SHA1 = 0x0004, TPM2_ALG_KEYEDHASH = 0x0008, TPM2_ALG_SHA256 = 0x000B, @@ -127,6 +128,7 @@ enum tpm2_permanent_handles { }; enum tpm2_capabilities { + TPM2_CAP_PCRS = 5, TPM2_CAP_TPM_PROPERTIES = 6, }; @@ -187,6 +189,8 @@ struct tpm_chip { const struct attribute_group *groups[3]; unsigned int groups_cnt; + + u16 active_banks[7]; #ifdef CONFIG_ACPI acpi_handle acpi_dev_handle; char ppi_version[TPM_PPI_VERSION_LEN + 1]; @@ -540,4 +544,5 @@ int tpm2_auto_startup(struct tpm_chip *chip); void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type); unsigned long tpm2_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal); int tpm2_probe(struct tpm_chip *chip); +ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip); #endif diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c index 42fe3dde0d8c..6fbd42c2a528 100644 --- a/drivers/char/tpm/tpm2-cmd.c +++ b/drivers/char/tpm/tpm2-cmd.c @@ -1030,3 +1030,80 @@ out: rc = -ENODEV; return rc; } + +struct tpm2_pcr_selection { + __be16 hash_alg; + u8 size_of_select; + u8 pcr_select[3]; +} __packed; + +/** + * tpm2_get_pcr_allocation() - get TPM active PCR banks. + * + * @chip: TPM chip to use. + * + * Return: Same as with tpm_transmit_cmd. + */ +ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip) +{ + struct tpm2_pcr_selection pcr_selection; + struct tpm_buf buf; + void *marker; + void *end; + void *pcr_select_offset; + unsigned int count; + u32 sizeof_pcr_selection; + u32 rsp_len; + int rc; + int i = 0; + + rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY); + if (rc) + return rc; + + tpm_buf_append_u32(&buf, TPM2_CAP_PCRS); + tpm_buf_append_u32(&buf, 0); + tpm_buf_append_u32(&buf, 1); + + rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 9, 0, + "get tpm pcr allocation"); + if (rc) + goto out; + + count = be32_to_cpup( + (__be32 *)&buf.data[TPM_HEADER_SIZE + 5]); + + if (count > ARRAY_SIZE(chip->active_banks)) { + rc = -ENODEV; + goto out; + } + + marker = &buf.data[TPM_HEADER_SIZE + 9]; + + rsp_len = be32_to_cpup((__be32 *)&buf.data[2]); + end = &buf.data[rsp_len]; + + for (i = 0; i < count; i++) { + pcr_select_offset = marker + + offsetof(struct tpm2_pcr_selection, size_of_select); + if (pcr_select_offset >= end) { + rc = -EFAULT; + break; + } + + memcpy(&pcr_selection, marker, sizeof(pcr_selection)); + chip->active_banks[i] = be16_to_cpu(pcr_selection.hash_alg); + sizeof_pcr_selection = sizeof(pcr_selection.hash_alg) + + sizeof(pcr_selection.size_of_select) + + pcr_selection.size_of_select; + marker = marker + sizeof_pcr_selection; + } + +out: + if (i < ARRAY_SIZE(chip->active_banks)) + chip->active_banks[i] = TPM2_ALG_ERROR; + + tpm_buf_destroy(&buf); + + return rc; +}