Messages in this thread | | | Date | Thu, 12 Jan 2017 20:20:44 +0200 | From | Jarkko Sakkinen <> | Subject | Re: [PATCH v3 2/2] tpm: enhance TPM 2.0 PCR extend to support multiple banks |
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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.
> + > #if defined(CONFIG_ACPI) > int tpm_read_log_acpi(struct tpm_chip *chip); > #else > -- > 2.5.0 >
/Jarkko
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