Messages in this thread | | | Subject | Re: [PATCH v3 2/2] tpm: enhance TPM 2.0 PCR extend to support multiple banks | From | Nayna <> | Date | Fri, 13 Jan 2017 12:44:15 +0530 |
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On 01/12/2017 11:50 PM, Jarkko Sakkinen wrote: > On Thu, Jan 12, 2017 at 11:58:10AM -0500, Nayna Jain wrote: >> 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 <nayna@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 > > In the commit message you did not mention this. > >> ---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 <safford@watson.ibm.com> >> * Reiner Sailer <sailer@watson.ibm.com> >> * Kylene Hall <kjhall@us.ibm.com> >> + * Nayna Jain <nayna@linux.vnet.ibm.com> > > Remove. > >> * >> * Maintained by: <tpmdd-devel@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". >> + */ > > Please remove this comment > >> + >> +struct tpmt_ha { >> + u16 alg_id; >> + u8 digest[SHA384_DIGEST_SIZE]; >> +} __packed; > > struct tpm2_hash > >> +struct tpml_digest_values { >> + u32 count; >> + struct tpmt_ha digests[TPM2_ACTIVE_PCR_BANKS]; >> +} __packed; > > Please remove this structure.
Sorry Jarkko, I didn't understand this comment. Why do we want to remove this structure.
Thanks & Regards, - Nayna
> >> + >> #if defined(CONFIG_ACPI) >> int tpm_read_log_acpi(struct tpm_chip *chip); >> #else >> -- >> 2.5.0 >> > > /Jarkko >
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