Messages in this thread | | | Subject | Re: [PATCH v6 2/2] tpm: enhance TPM 2.0 PCR extend to support multiple banks | From | Nayna <> | Date | Tue, 24 Jan 2017 18:34:54 +0530 |
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On 01/24/2017 05:29 PM, Jarkko Sakkinen wrote: > On Mon, Jan 23, 2017 at 10:11:48PM +0530, Nayna wrote: >> >> >> 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. >> > > If it is common, why is it in tpm_eventlog.h and not in tpm.h?
Hmm, the way I took it was that all event log structs are in tpm_eventlog.h. So, I have defined all structs related to event log into tpm_eventlog.h, including this one.
Also, currently, tpm_eventlog.h has no dependency on tpm.h, but tpm.h does include tpm_eventlog.h.
Hmm.. is it an issue to have it in tpm_eventlog.h ?
Thanks & Regards, - Nayna
> >> Thanks & Regards, >> - Nayna > > /Jarkko >
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