Messages in this thread | | | Subject | Re: [PATCH v6 2/2] tpm: enhance TPM 2.0 PCR extend to support multiple banks | From | Nayna <> | Date | Mon, 23 Jan 2017 22:11:48 +0530 |
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On 01/23/2017 08:49 PM, Jarkko Sakkinen wrote: > On Fri, Jan 20, 2017 at 12:05:13PM -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. >> >> This patch reuses the defined digest sizes from the crypto subsystem, >> adding a dependency on CRYPTO_HASH_INFO module. >> >> [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> >> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> >> --- >> drivers/char/tpm/Kconfig | 1 + >> drivers/char/tpm/tpm-interface.c | 15 ++++++- >> drivers/char/tpm/tpm.h | 3 +- >> drivers/char/tpm/tpm2-cmd.c | 91 +++++++++++++++++++++------------------- >> drivers/char/tpm/tpm_eventlog.h | 7 ++++ >> 5 files changed, 73 insertions(+), 44 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 a3461cb..cf959c3 100644 >> --- a/drivers/char/tpm/tpm-interface.c >> +++ b/drivers/char/tpm/tpm-interface.c >> @@ -772,13 +772,26 @@ int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash) >> struct tpm_cmd_t cmd; >> int rc; >> struct tpm_chip *chip; >> + int max_active_banks = ARRAY_SIZE(chip->active_banks); >> + struct tpm2_digest digest_list[max_active_banks]; >> + u32 count = 0; >> + int i; >> >> chip = tpm_chip_find_get(chip_num); >> if (chip == NULL) >> return -ENODEV; >> >> if (chip->flags & TPM_CHIP_FLAG_TPM2) { >> - rc = tpm2_pcr_extend(chip, pcr_idx, hash); >> + memset(digest_list, 0, sizeof(digest_list)); >> + >> + for (i = 0; (chip->active_banks[i] != TPM2_ALG_ERROR) && >> + (i < max_active_banks); i++) { >> + digest_list[i].alg_id = chip->active_banks[i]; >> + memcpy(digest_list[i].digest, hash, TPM_DIGEST_SIZE); >> + count++; >> + } >> + >> + rc = tpm2_pcr_extend(chip, pcr_idx, count, digest_list); >> tpm_put_ops(chip); >> return rc; >> } >> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h >> index c291f19..07a0677 100644 >> --- a/drivers/char/tpm/tpm.h >> +++ b/drivers/char/tpm/tpm.h >> @@ -534,7 +534,8 @@ 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, u32 count, >> + struct tpm2_digest *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 0e000a3..d78adb8 100644 >> --- a/drivers/char/tpm/tpm2-cmd.c >> +++ b/drivers/char/tpm/tpm2-cmd.c >> @@ -53,22 +53,6 @@ struct tpm2_pcr_read_out { >> u8 digest[TPM_DIGEST_SIZE]; >> } __packed; >> >> -struct tpm2_null_auth_area { >> - __be32 handle; >> - __be16 nonce_size; >> - u8 attributes; >> - __be16 auth_size; >> -} __packed; >> - >> -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]; >> -} __packed; >> - >> struct tpm2_get_tpm_pt_in { >> __be32 cap_id; >> __be32 property_id; >> @@ -97,7 +81,6 @@ union tpm2_cmd_params { >> struct tpm2_self_test_in selftest_in; >> struct tpm2_pcr_read_in pcrread_in; >> struct tpm2_pcr_read_out pcrread_out; >> - struct tpm2_pcr_extend_in pcrextend_in; >> struct tpm2_get_tpm_pt_in get_tpm_pt_in; >> struct tpm2_get_tpm_pt_out get_tpm_pt_out; >> struct tpm2_get_random_in getrandom_in; >> @@ -290,46 +273,68 @@ 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) >> -}; >> +struct tpm2_null_auth_area { >> + __be32 handle; >> + __be16 nonce_size; >> + u8 attributes; >> + __be16 auth_size; >> +} __packed; >> >> /** >> * 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. >> + * @count: number of digests passed. >> + * @digests: list of pcr banks and corresponding digest values to extend. >> * >> * 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, u32 count, >> + struct tpm2_digest *digests) >> { >> - struct tpm2_cmd cmd; >> + struct tpm_buf buf; >> + struct tpm2_null_auth_area auth_area; >> int rc; >> + int i; >> + int j; >> + >> + if (count > ARRAY_SIZE(chip->active_banks)) >> + return -EINVAL; >> >> - 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, count); >> + >> + for (i = 0; i < count; i++) { >> + for (j = 0; j < ARRAY_SIZE(tpm2_hash_map); j++) { >> + if (digests[i].alg_id != tpm2_hash_map[j].tpm_id) >> + continue; >> + >> + tpm_buf_append_u16(&buf, digests[i].alg_id); >> + tpm_buf_append(&buf, (const unsigned char >> + *)&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; >> } >> >> @@ -993,6 +998,8 @@ int tpm2_auto_startup(struct tpm_chip *chip) >> } >> } >> >> + rc = tpm2_get_pcr_allocation(chip); >> + >> out: >> if (rc > 0) >> rc = -ENODEV; >> diff --git a/drivers/char/tpm/tpm_eventlog.h b/drivers/char/tpm/tpm_eventlog.h >> index 1660d74..b5ae372 100644 >> --- a/drivers/char/tpm/tpm_eventlog.h >> +++ b/drivers/char/tpm/tpm_eventlog.h >> @@ -2,6 +2,8 @@ >> #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' */ >> @@ -73,6 +75,11 @@ enum tcpa_pc_event_ids { >> HOST_TABLE_OF_DEVICES, >> }; >> >> +struct tpm2_digest { >> + u16 alg_id; >> + u8 digest[SHA512_DIGEST_SIZE]; >> +} __packed; > > Shouldn't this be in tpm.h?
This is a struct common for TPM 2.0 extend and eventlog structure i.e struct tcg_pcr_event2. And so I preferred to place it here.
Thanks & Regards, - Nayna
> > /Jarkko >
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