The current TPM 2.0 device driver extends only the SHA1 PCR bank but the TCG Specification[1] recommends extending all active PCR banks, to prevent malicious users from setting unused PCR banks with fake measurements and quoting them.
The existing in-kernel interface(tpm_pcr_extend()) expects only a SHA1 digest. To extend all active PCR banks with differing digest sizes, the SHA1 digest is padded with trailing 0's as needed. [1] TPM 2.0 Specification referred here is "TCG PC Client Specific Platform Firmware Profile for TPM 2.0" Signed-off-by: Nayna Jain <na...@linux.vnet.ibm.com> --- drivers/char/tpm/Kconfig | 1 + drivers/char/tpm/tpm-interface.c | 16 +++++++++- drivers/char/tpm/tpm.h | 3 +- drivers/char/tpm/tpm2-cmd.c | 68 +++++++++++++++++++++++----------------- drivers/char/tpm/tpm_eventlog.h | 18 +++++++++++ 5 files changed, 75 insertions(+), 31 deletions(-) diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig index 277186d..af985cc 100644 --- a/drivers/char/tpm/Kconfig +++ b/drivers/char/tpm/Kconfig @@ -6,6 +6,7 @@ menuconfig TCG_TPM tristate "TPM Hardware Support" depends on HAS_IOMEM select SECURITYFS + select CRYPTO_HASH_INFO ---help--- If you have a TPM security chip in your system, which implements the Trusted Computing Group's specification, diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c index fecdd3f..e037dd2 100644 --- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -7,6 +7,7 @@ * Dave Safford <saff...@watson.ibm.com> * Reiner Sailer <sai...@watson.ibm.com> * Kylene Hall <kjh...@us.ibm.com> + * Nayna Jain <na...@linux.vnet.ibm.com> * * Maintained by: <tpmdd-de...@lists.sourceforge.net> * @@ -759,6 +760,7 @@ static const struct tpm_input_header pcrextend_header = { int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash) { struct tpm_cmd_t cmd; + int i; int rc; struct tpm_chip *chip; @@ -767,7 +769,19 @@ int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash) return -ENODEV; if (chip->flags & TPM_CHIP_FLAG_TPM2) { - rc = tpm2_pcr_extend(chip, pcr_idx, hash); + struct tpml_digest_values d_values; + + memset(&d_values, 0, sizeof(d_values)); + + for (i = 0; (chip->active_banks[i] != 0) && + (i < ARRAY_SIZE(chip->active_banks)); i++) { + d_values.digests[i].alg_id = chip->active_banks[i]; + memcpy(d_values.digests[i].digest, hash, + TPM_DIGEST_SIZE); + d_values.count++; + } + + rc = tpm2_pcr_extend(chip, pcr_idx, &d_values); tpm_put_ops(chip); return rc; } diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h index dddd573..dd82d58 100644 --- a/drivers/char/tpm/tpm.h +++ b/drivers/char/tpm/tpm.h @@ -533,7 +533,8 @@ static inline void tpm_add_ppi(struct tpm_chip *chip) #endif int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf); -int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash); +int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, + struct tpml_digest_values *digests); int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max); int tpm2_seal_trusted(struct tpm_chip *chip, struct trusted_key_payload *payload, diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c index 87388921..5027a54 100644 --- a/drivers/char/tpm/tpm2-cmd.c +++ b/drivers/char/tpm/tpm2-cmd.c @@ -64,9 +64,7 @@ struct tpm2_pcr_extend_in { __be32 pcr_idx; __be32 auth_area_size; struct tpm2_null_auth_area auth_area; - __be32 digest_cnt; - __be16 hash_alg; - u8 digest[TPM_DIGEST_SIZE]; + struct tpml_digest_values digests; } __packed; struct tpm2_get_tpm_pt_in { @@ -296,46 +294,58 @@ int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf) return rc; } -#define TPM2_GET_PCREXTEND_IN_SIZE \ - (sizeof(struct tpm_input_header) + \ - sizeof(struct tpm2_pcr_extend_in)) - -static const struct tpm_input_header tpm2_pcrextend_header = { - .tag = cpu_to_be16(TPM2_ST_SESSIONS), - .length = cpu_to_be32(TPM2_GET_PCREXTEND_IN_SIZE), - .ordinal = cpu_to_be32(TPM2_CC_PCR_EXTEND) -}; - /** * tpm2_pcr_extend() - extend a PCR value * * @chip: TPM chip to use. * @pcr_idx: index of the PCR. - * @hash: hash value to use for the extend operation. + * @digests: list of pcr banks and corresponding hash values to be extended. * * Return: Same as with tpm_transmit_cmd. */ -int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash) +int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, + struct tpml_digest_values *digests) { - struct tpm2_cmd cmd; + struct tpm_buf buf; + struct tpm2_null_auth_area auth_area; int rc; + int i; + int j; - cmd.header.in = tpm2_pcrextend_header; - cmd.params.pcrextend_in.pcr_idx = cpu_to_be32(pcr_idx); - cmd.params.pcrextend_in.auth_area_size = - cpu_to_be32(sizeof(struct tpm2_null_auth_area)); - cmd.params.pcrextend_in.auth_area.handle = - cpu_to_be32(TPM2_RS_PW); - cmd.params.pcrextend_in.auth_area.nonce_size = 0; - cmd.params.pcrextend_in.auth_area.attributes = 0; - cmd.params.pcrextend_in.auth_area.auth_size = 0; - cmd.params.pcrextend_in.digest_cnt = cpu_to_be32(1); - cmd.params.pcrextend_in.hash_alg = cpu_to_be16(TPM2_ALG_SHA1); - memcpy(cmd.params.pcrextend_in.digest, hash, TPM_DIGEST_SIZE); + rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_PCR_EXTEND); + if (rc) + return rc; - rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0, + tpm_buf_append_u32(&buf, pcr_idx); + + auth_area.handle = cpu_to_be32(TPM2_RS_PW); + auth_area.nonce_size = 0; + auth_area.attributes = 0; + auth_area.auth_size = 0; + + tpm_buf_append_u32(&buf, sizeof(struct tpm2_null_auth_area)); + tpm_buf_append(&buf, (const unsigned char *)&auth_area, + sizeof(auth_area)); + tpm_buf_append_u32(&buf, digests->count); + + for (i = 0; i < digests->count; i++) { + for (j = 0; j < ARRAY_SIZE(tpm2_hash_map); j++) { + if (digests->digests[i].alg_id != + tpm2_hash_map[j].tpm_id) + continue; + + tpm_buf_append_u16(&buf, digests->digests[i].alg_id); + tpm_buf_append(&buf, (const unsigned char + *)&digests->digests[i].digest, + hash_digest_size[tpm2_hash_map[j].crypto_id]); + } + } + + rc = tpm_transmit_cmd(chip, buf.data, tpm_buf_length(&buf), 0, "attempting extend a PCR value"); + tpm_buf_destroy(&buf); + return rc; } diff --git a/drivers/char/tpm/tpm_eventlog.h b/drivers/char/tpm/tpm_eventlog.h index 1660d74..2e47f4d 100644 --- a/drivers/char/tpm/tpm_eventlog.h +++ b/drivers/char/tpm/tpm_eventlog.h @@ -2,9 +2,12 @@ #ifndef __TPM_EVENTLOG_H__ #define __TPM_EVENTLOG_H__ +#include <crypto/hash_info.h> + #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 #ifdef CONFIG_PPC64 #define do_endian_conversion(x) be32_to_cpu(x) @@ -73,6 +76,21 @@ enum tcpa_pc_event_ids { HOST_TABLE_OF_DEVICES, }; +/** + * Digest structures for TPM 2.0 as defined in document + * Trusted Platform Module Library Part 2: Structures, Family "2.0". + */ + +struct tpmt_ha { + u16 alg_id; + u8 digest[SHA384_DIGEST_SIZE]; +} __packed; + +struct tpml_digest_values { + u32 count; + struct tpmt_ha digests[TPM2_ACTIVE_PCR_BANKS]; +} __packed; + #if defined(CONFIG_ACPI) int tpm_read_log_acpi(struct tpm_chip *chip); #else -- 2.5.0