On 01/17/2017 09:43 PM, Jarkko Sakkinen wrote:
On Tue, Jan 17, 2017 at 01:23:44PM +0530, Nayna wrote:


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 <[email protected]>
---
   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 <[email protected]>
    * Reiner Sailer <[email protected]>
    * Kylene Hall <[email protected]>
+ * Nayna Jain <[email protected]>

Remove.

    *
    * Maintained by: <[email protected]>
    *
@@ -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 tpm2_hash is already defined in tpm2-cmd.c as below

struct tpm2_hash {
         unsigned int crypto_id;
         unsigned int tpm_id;
};

Though, I think this probably needs a different name, probably as "struct
tpm2_hash_ids_map" or just "struct tpm2_hash_ids"

and then I rename struct tpmt_ha as struct tpm2_hash.

If this sounds good, I will also rename existing tpm2_hash as different
patch.

Thanks & Regards,
    - Nayna

What if you just use tpm2_digest for the new structure?

I can.

Thanks & Regards,
- Nayna



/Jarkko


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