[PATCH v6 0/7] tpm: retrieve digest size of unknown algorithms from TPM

[PATCH v6 0/7] tpm: retrieve digest size of unknown algorithms from TPM

[Roberto Sassu]

Update

This version of the patch set includes an additional patch (7/7) which
modifies the definition of tpm_pcr_extend() and tpm2_pcr_extend(). The new
patch has been included to facilitate the review of the changes to support
TPM 2.0 crypto agility for reading/extending PCRs.


Original patch set description

The TPM driver currently relies on the crypto subsystem to determine the
digest size of supported TPM algorithms. In the future, TPM vendors might
implement new algorithms in their chips, and those algorithms might not
be supported by the crypto subsystem.

Usually, vendors provide patches for the new hardware, and likely
the crypto subsystem will be updated before the new algorithm is
introduced. However, old kernels might be updated later, after patches
are included in the mainline kernel. This would leave the opportunity
for attackers to misuse PCRs, as PCR banks with an unknown algorithm
are not extended.

This patch set provides a long term solution for this issue. If a TPM
algorithm is not known by the crypto subsystem, the TPM driver retrieves
the digest size from the TPM with a PCR read. All the PCR banks are
extended, even if the algorithm is not yet supported by the crypto
subsystem.

PCR bank information (TPM algorithm ID, digest size, crypto subsystem ID)
is stored in the tpm_chip structure and available for users of the TPM
driver.

Changelog

v5:
- rename digest_struct variable to digest
- add _head suffix to tcg_efi_specid_event and tcg_pcr_event2
- rename digest_size member of tpm_bank_list to extend_size
- change type of alg_id member of tpm_bank list from u8 to u16
- add missing semi-colon in pcrlock()

v4:
- rename active_banks to allocated_banks
- replace kmalloc_array() with kcalloc()
- increment nr_allocated_banks if at least one PCR in the bank is selected
- pass multiple digests to tpm_pcr_extend()

v3:
- remove end marker change
- replace active_banks static array with pointer to dynamic array
- remove TPM2_ACTIVE_PCR_BANKS

v2:
- change the end marker of the active_banks array
- check digest size from output of PCR read command
- remove count parameter from tpm_pcr_read() and tpm2_pcr_read()

v1:
- modify definition of tpm_pcr_read()
- move hash algorithms and definition of tpm2_digest to include/linux/tpm.h

Roberto Sassu (7):
  tpm: dynamically allocate the allocated_banks array
  tpm: add _head suffix to tcg_efi_specid_event and tcg_pcr_event2
  tpm: rename and export tpm2_digest and tpm2_algorithms
  tpm: modify tpm_pcr_read() definition to pass a TPM hash algorithm
  tpm: retrieve digest size of unknown algorithms with PCR read
  tpm: ensure that the output of PCR read contains the correct digest
    size
  tpm: pass an array of tpm_bank_list structures to tpm_pcr_extend()

 drivers/char/tpm/eventlog/tpm2.c    |  12 +--
 drivers/char/tpm/tpm-chip.c         |   1 +
 drivers/char/tpm/tpm-interface.c    |  36 +++----
 drivers/char/tpm/tpm.h              |  23 ++---
 drivers/char/tpm/tpm1-cmd.c         |  26 ++++-
 drivers/char/tpm/tpm2-cmd.c         | 154 +++++++++++++++++++++-------
 include/linux/tpm.h                 |  43 +++++++-
 include/linux/tpm_eventlog.h        |  19 +---
 security/integrity/ima/ima_crypto.c |  10 +-
 security/integrity/ima/ima_queue.c  |   5 +-
 security/keys/trusted.c             |   5 +-
 11 files changed, 220 insertions(+), 114 deletions(-)

-- 
2.17.1

[PATCH v6 1/7] tpm: dynamically allocate the allocated_banks array

[Roberto Sassu]

This patch renames active_banks (member of tpm_chip) to allocated_banks,
stores the number of allocated PCR banks in nr_allocated_banks (new member
of tpm_chip), and replaces the static array with a pointer to a dynamically
allocated array.

tpm2_get_pcr_allocation() determines if a PCR bank is allocated by checking
the mask in the TPML_PCR_SELECTION structure returned by the TPM for
TPM2_Get_Capability(). One PCR bank with algorithm set to SHA1 is always
allocated for TPM 1.x.

As a consequence of the introduction of nr_allocated_banks,
tpm_pcr_extend() does not check anymore if the algorithm stored in tpm_chip
is equal to zero.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 drivers/char/tpm/tpm-chip.c      |  1 +
 drivers/char/tpm/tpm-interface.c | 18 +++++++++--------
 drivers/char/tpm/tpm.h           |  3 ++-
 drivers/char/tpm/tpm1-cmd.c      | 10 ++++++++++
 drivers/char/tpm/tpm2-cmd.c      | 34 ++++++++++++++++++++++----------
 5 files changed, 47 insertions(+), 19 deletions(-)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 32db84683c40..ce851c62bb68 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -160,6 +160,7 @@ static void tpm_dev_release(struct device *dev)
 	kfree(chip->log.bios_event_log);
 	kfree(chip->work_space.context_buf);
 	kfree(chip->work_space.session_buf);
+	kfree(chip->allocated_banks);
 	kfree(chip);
 }
 
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index d9439f9abe78..7b80919228be 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -488,8 +488,7 @@ EXPORT_SYMBOL_GPL(tpm_pcr_read);
 int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash)
 {
 	int rc;
-	struct tpm2_digest digest_list[ARRAY_SIZE(chip->active_banks)];
-	u32 count = 0;
+	struct tpm2_digest *digest_list;
 	int i;
 
 	chip = tpm_find_get_ops(chip);
@@ -497,16 +496,19 @@ int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash)
 		return -ENODEV;
 
 	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
-		memset(digest_list, 0, sizeof(digest_list));
+		digest_list = kcalloc(chip->nr_allocated_banks,
+				      sizeof(*digest_list), GFP_KERNEL);
+		if (!digest_list)
+			return -ENOMEM;
 
-		for (i = 0; i < ARRAY_SIZE(chip->active_banks) &&
-			    chip->active_banks[i] != TPM2_ALG_ERROR; i++) {
-			digest_list[i].alg_id = chip->active_banks[i];
+		for (i = 0; i < chip->nr_allocated_banks; i++) {
+			digest_list[i].alg_id = chip->allocated_banks[i];
 			memcpy(digest_list[i].digest, hash, TPM_DIGEST_SIZE);
-			count++;
 		}
 
-		rc = tpm2_pcr_extend(chip, pcr_idx, count, digest_list);
+		rc = tpm2_pcr_extend(chip, pcr_idx, chip->nr_allocated_banks,
+				     digest_list);
+		kfree(digest_list);
 		tpm_put_ops(chip);
 		return rc;
 	}
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index f27d1f38a93d..6b94306ab7c5 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -257,7 +257,8 @@ struct tpm_chip {
 	const struct attribute_group *groups[3];
 	unsigned int groups_cnt;
 
-	u16 active_banks[7];
+	u32 nr_allocated_banks;
+	u16 *allocated_banks;
 #ifdef CONFIG_ACPI
 	acpi_handle acpi_dev_handle;
 	char ppi_version[TPM_PPI_VERSION_LEN + 1];
diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
index 6f306338953b..0874743ca96d 100644
--- a/drivers/char/tpm/tpm1-cmd.c
+++ b/drivers/char/tpm/tpm1-cmd.c
@@ -709,6 +709,16 @@ int tpm1_auto_startup(struct tpm_chip *chip)
 		goto out;
 	}
 
+	chip->allocated_banks = kcalloc(1, sizeof(*chip->allocated_banks),
+					GFP_KERNEL);
+	if (!chip->allocated_banks) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	chip->allocated_banks[0] = TPM2_ALG_SHA1;
+	chip->nr_allocated_banks = 1;
+
 	return rc;
 out:
 	if (rc > 0)
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index a6bec13afa69..245669a7aba5 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -234,7 +234,7 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
 	int i;
 	int j;
 
-	if (count > ARRAY_SIZE(chip->active_banks))
+	if (count > chip->nr_allocated_banks)
 		return -EINVAL;
 
 	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_PCR_EXTEND);
@@ -825,11 +825,14 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
 	void *marker;
 	void *end;
 	void *pcr_select_offset;
-	unsigned int count;
 	u32 sizeof_pcr_selection;
+	u32 nr_possible_banks;
+	u32 nr_alloc_banks = 0;
+	u16 hash_alg;
 	u32 rsp_len;
 	int rc;
 	int i = 0;
+	int j;
 
 	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
 	if (rc)
@@ -844,11 +847,14 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
 	if (rc)
 		goto out;
 
-	count = be32_to_cpup(
+	nr_possible_banks = be32_to_cpup(
 		(__be32 *)&buf.data[TPM_HEADER_SIZE + 5]);
 
-	if (count > ARRAY_SIZE(chip->active_banks)) {
-		rc = -ENODEV;
+	chip->allocated_banks = kcalloc(nr_possible_banks,
+					sizeof(*chip->allocated_banks),
+					GFP_KERNEL);
+	if (!chip->allocated_banks) {
+		rc = -ENOMEM;
 		goto out;
 	}
 
@@ -857,7 +863,7 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
 	rsp_len = be32_to_cpup((__be32 *)&buf.data[2]);
 	end = &buf.data[rsp_len];
 
-	for (i = 0; i < count; i++) {
+	for (i = 0; i < nr_possible_banks; i++) {
 		pcr_select_offset = marker +
 			offsetof(struct tpm2_pcr_selection, size_of_select);
 		if (pcr_select_offset >= end) {
@@ -866,17 +872,25 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
 		}
 
 		memcpy(&pcr_selection, marker, sizeof(pcr_selection));
-		chip->active_banks[i] = be16_to_cpu(pcr_selection.hash_alg);
+		hash_alg = be16_to_cpu(pcr_selection.hash_alg);
+
+		for (j = 0; j < pcr_selection.size_of_select; j++)
+			if (pcr_selection.pcr_select[j])
+				break;
+
+		if (j < pcr_selection.size_of_select) {
+			chip->allocated_banks[nr_alloc_banks] = hash_alg;
+			nr_alloc_banks++;
+		}
+
 		sizeof_pcr_selection = sizeof(pcr_selection.hash_alg) +
 			sizeof(pcr_selection.size_of_select) +
 			pcr_selection.size_of_select;
 		marker = marker + sizeof_pcr_selection;
 	}
 
+	chip->nr_allocated_banks = nr_alloc_banks;
 out:
-	if (i < ARRAY_SIZE(chip->active_banks))
-		chip->active_banks[i] = TPM2_ALG_ERROR;
-
 	tpm_buf_destroy(&buf);
 
 	return rc;
-- 
2.17.1

[PATCH v6 2/7] tpm: add _head suffix to tcg_efi_specid_event and tcg_pcr_event2

[Roberto Sassu]

TCG defines two structures, TCG_EfiSpecIDEventStruct and TCG_PCR_EVENT2,
which contain variable-sized arrays in the middle of the definition.

Since these structures are not suitable for type casting, this patch
removes structure members after the variable-sized arrays and adds the
_head suffix to the structure name, to indicate that the renamed structures
do not contain all fields defined by TCG.

Lastly, given that variable-sized arrays are now in the last position, and
given that the size of the arrays cannot be determined in advance, this
patch also sets the size of those arrays to zero and removes the definition
of TPM2_ACTIVE_PCR_BANKS.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
 drivers/char/tpm/eventlog/tpm2.c | 12 ++++++------
 include/linux/tpm_eventlog.h     | 12 ++++--------
 2 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/drivers/char/tpm/eventlog/tpm2.c b/drivers/char/tpm/eventlog/tpm2.c
index 1b8fa9de2cac..d8b77133a83a 100644
--- a/drivers/char/tpm/eventlog/tpm2.c
+++ b/drivers/char/tpm/eventlog/tpm2.c
@@ -37,10 +37,10 @@
  *
  * Returns size of the event. If it is an invalid event, returns 0.
  */
-static int calc_tpm2_event_size(struct tcg_pcr_event2 *event,
+static int calc_tpm2_event_size(struct tcg_pcr_event2_head *event,
 				struct tcg_pcr_event *event_header)
 {
-	struct tcg_efi_specid_event *efispecid;
+	struct tcg_efi_specid_event_head *efispecid;
 	struct tcg_event_field *event_field;
 	void *marker;
 	void *marker_start;
@@ -55,7 +55,7 @@ static int calc_tpm2_event_size(struct tcg_pcr_event2 *event,
 	marker = marker + sizeof(event->pcr_idx) + sizeof(event->event_type)
 		+ sizeof(event->count);
 
-	efispecid = (struct tcg_efi_specid_event *)event_header->event;
+	efispecid = (struct tcg_efi_specid_event_head *)event_header->event;
 
 	/* Check if event is malformed. */
 	if (event->count > efispecid->num_algs)
@@ -95,7 +95,7 @@ static void *tpm2_bios_measurements_start(struct seq_file *m, loff_t *pos)
 	void *addr = log->bios_event_log;
 	void *limit = log->bios_event_log_end;
 	struct tcg_pcr_event *event_header;
-	struct tcg_pcr_event2 *event;
+	struct tcg_pcr_event2_head *event;
 	size_t size;
 	int i;
 
@@ -136,7 +136,7 @@ static void *tpm2_bios_measurements_next(struct seq_file *m, void *v,
 					 loff_t *pos)
 {
 	struct tcg_pcr_event *event_header;
-	struct tcg_pcr_event2 *event;
+	struct tcg_pcr_event2_head *event;
 	struct tpm_chip *chip = m->private;
 	struct tpm_bios_log *log = &chip->log;
 	void *limit = log->bios_event_log_end;
@@ -180,7 +180,7 @@ static int tpm2_binary_bios_measurements_show(struct seq_file *m, void *v)
 	struct tpm_chip *chip = m->private;
 	struct tpm_bios_log *log = &chip->log;
 	struct tcg_pcr_event *event_header = log->bios_event_log;
-	struct tcg_pcr_event2 *event = v;
+	struct tcg_pcr_event2_head *event = v;
 	void *temp_ptr;
 	size_t size;
 
diff --git a/include/linux/tpm_eventlog.h b/include/linux/tpm_eventlog.h
index 20d9da77fc11..f0ef6cc97f00 100644
--- a/include/linux/tpm_eventlog.h
+++ b/include/linux/tpm_eventlog.h
@@ -8,7 +8,6 @@
 #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
 
 #define EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2 0x1
 #define EFI_TCG2_EVENT_LOG_FORMAT_TCG_2   0x2
@@ -82,7 +81,7 @@ struct tcg_efi_specid_event_algs {
 	u16 digest_size;
 } __packed;
 
-struct tcg_efi_specid_event {
+struct tcg_efi_specid_event_head {
 	u8 signature[16];
 	u32 platform_class;
 	u8 spec_version_minor;
@@ -90,9 +89,7 @@ struct tcg_efi_specid_event {
 	u8 spec_errata;
 	u8 uintnsize;
 	u32 num_algs;
-	struct tcg_efi_specid_event_algs digest_sizes[TPM2_ACTIVE_PCR_BANKS];
-	u8 vendor_info_size;
-	u8 vendor_info[0];
+	struct tcg_efi_specid_event_algs digest_sizes[0];
 } __packed;
 
 struct tcg_pcr_event {
@@ -113,12 +110,11 @@ struct tpm2_digest {
 	u8 digest[SHA512_DIGEST_SIZE];
 } __packed;
 
-struct tcg_pcr_event2 {
+struct tcg_pcr_event2_head {
 	u32 pcr_idx;
 	u32 event_type;
 	u32 count;
-	struct tpm2_digest digests[TPM2_ACTIVE_PCR_BANKS];
-	struct tcg_event_field event;
+	struct tpm2_digest digests[0];
 } __packed;
 
 #endif
-- 
2.17.1

[PATCH v6 3/7] tpm: rename and export tpm2_digest and tpm2_algorithms

[Roberto Sassu]

Rename tpm2_* to tpm_* and move the definitions to include/linux/tpm.h so
that these can be used by other kernel subsystems (e.g. IMA).

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
---
 drivers/char/tpm/tpm-interface.c |  2 +-
 drivers/char/tpm/tpm.h           | 13 +------------
 drivers/char/tpm/tpm1-cmd.c      |  2 +-
 drivers/char/tpm/tpm2-cmd.c      | 18 +++++++++---------
 include/linux/tpm.h              | 18 ++++++++++++++++++
 include/linux/tpm_eventlog.h     |  9 ++-------
 6 files changed, 32 insertions(+), 30 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 7b80919228be..96c8261d0f04 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -488,7 +488,7 @@ EXPORT_SYMBOL_GPL(tpm_pcr_read);
 int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash)
 {
 	int rc;
-	struct tpm2_digest *digest_list;
+	struct tpm_digest *digest_list;
 	int i;
 
 	chip = tpm_find_get_ops(chip);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 6b94306ab7c5..e961e5c5d197 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -122,17 +122,6 @@ enum tpm2_return_codes {
 	TPM2_RC_RETRY		= 0x0922,
 };
 
-enum tpm2_algorithms {
-	TPM2_ALG_ERROR		= 0x0000,
-	TPM2_ALG_SHA1		= 0x0004,
-	TPM2_ALG_KEYEDHASH	= 0x0008,
-	TPM2_ALG_SHA256		= 0x000B,
-	TPM2_ALG_SHA384		= 0x000C,
-	TPM2_ALG_SHA512		= 0x000D,
-	TPM2_ALG_NULL		= 0x0010,
-	TPM2_ALG_SM3_256	= 0x0012,
-};
-
 enum tpm2_command_codes {
 	TPM2_CC_FIRST		        = 0x011F,
 	TPM2_CC_HIERARCHY_CONTROL       = 0x0121,
@@ -561,7 +550,7 @@ static inline u32 tpm2_rc_value(u32 rc)
 int tpm2_get_timeouts(struct tpm_chip *chip);
 int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf);
 int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
-		    struct tpm2_digest *digests);
+		    struct tpm_digest *digests);
 int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max);
 void tpm2_flush_context_cmd(struct tpm_chip *chip, u32 handle,
 			    unsigned int flags);
diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
index 0874743ca96d..ec4f197bae0a 100644
--- a/drivers/char/tpm/tpm1-cmd.c
+++ b/drivers/char/tpm/tpm1-cmd.c
@@ -716,7 +716,7 @@ int tpm1_auto_startup(struct tpm_chip *chip)
 		goto out;
 	}
 
-	chip->allocated_banks[0] = TPM2_ALG_SHA1;
+	chip->allocated_banks[0] = TPM_ALG_SHA1;
 	chip->nr_allocated_banks = 1;
 
 	return rc;
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 245669a7aba5..4afd14892cbf 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -33,11 +33,11 @@ struct tpm2_hash {
 };
 
 static struct tpm2_hash tpm2_hash_map[] = {
-	{HASH_ALGO_SHA1, TPM2_ALG_SHA1},
-	{HASH_ALGO_SHA256, TPM2_ALG_SHA256},
-	{HASH_ALGO_SHA384, TPM2_ALG_SHA384},
-	{HASH_ALGO_SHA512, TPM2_ALG_SHA512},
-	{HASH_ALGO_SM3_256, TPM2_ALG_SM3_256},
+	{HASH_ALGO_SHA1, TPM_ALG_SHA1},
+	{HASH_ALGO_SHA256, TPM_ALG_SHA256},
+	{HASH_ALGO_SHA384, TPM_ALG_SHA384},
+	{HASH_ALGO_SHA512, TPM_ALG_SHA512},
+	{HASH_ALGO_SM3_256, TPM_ALG_SM3_256},
 };
 
 int tpm2_get_timeouts(struct tpm_chip *chip)
@@ -192,7 +192,7 @@ int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
 	pcr_select[pcr_idx >> 3] = 1 << (pcr_idx & 0x7);
 
 	tpm_buf_append_u32(&buf, 1);
-	tpm_buf_append_u16(&buf, TPM2_ALG_SHA1);
+	tpm_buf_append_u16(&buf, TPM_ALG_SHA1);
 	tpm_buf_append_u8(&buf, TPM2_PCR_SELECT_MIN);
 	tpm_buf_append(&buf, (const unsigned char *)pcr_select,
 		       sizeof(pcr_select));
@@ -226,7 +226,7 @@ struct tpm2_null_auth_area {
  * Return: Same as with tpm_transmit_cmd.
  */
 int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
-		    struct tpm2_digest *digests)
+		    struct tpm_digest *digests)
 {
 	struct tpm_buf buf;
 	struct tpm2_null_auth_area auth_area;
@@ -449,7 +449,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 
 	/* public */
 	tpm_buf_append_u16(&buf, 14 + options->policydigest_len);
-	tpm_buf_append_u16(&buf, TPM2_ALG_KEYEDHASH);
+	tpm_buf_append_u16(&buf, TPM_ALG_KEYEDHASH);
 	tpm_buf_append_u16(&buf, hash);
 
 	/* policy */
@@ -464,7 +464,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 	}
 
 	/* public parameters */
-	tpm_buf_append_u16(&buf, TPM2_ALG_NULL);
+	tpm_buf_append_u16(&buf, TPM_ALG_NULL);
 	tpm_buf_append_u16(&buf, 0);
 
 	/* outside info */
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index b49a55cf775f..330c0a481581 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -22,12 +22,30 @@
 #ifndef __LINUX_TPM_H__
 #define __LINUX_TPM_H__
 
+#include <crypto/hash_info.h>
+
 #define TPM_DIGEST_SIZE 20	/* Max TPM v1.2 PCR size */
 
 struct tpm_chip;
 struct trusted_key_payload;
 struct trusted_key_options;
 
+enum tpm_algorithms {
+	TPM_ALG_ERROR		= 0x0000,
+	TPM_ALG_SHA1		= 0x0004,
+	TPM_ALG_KEYEDHASH	= 0x0008,
+	TPM_ALG_SHA256		= 0x000B,
+	TPM_ALG_SHA384		= 0x000C,
+	TPM_ALG_SHA512		= 0x000D,
+	TPM_ALG_NULL		= 0x0010,
+	TPM_ALG_SM3_256		= 0x0012,
+};
+
+struct tpm_digest {
+	u16 alg_id;
+	u8 digest[SHA512_DIGEST_SIZE];
+} __packed;
+
 enum TPM_OPS_FLAGS {
 	TPM_OPS_AUTO_STARTUP = BIT(0),
 };
diff --git a/include/linux/tpm_eventlog.h b/include/linux/tpm_eventlog.h
index f0ef6cc97f00..1d2d10a27bbe 100644
--- a/include/linux/tpm_eventlog.h
+++ b/include/linux/tpm_eventlog.h
@@ -3,7 +3,7 @@
 #ifndef __LINUX_TPM_EVENTLOG_H__
 #define __LINUX_TPM_EVENTLOG_H__
 
-#include <crypto/hash_info.h>
+#include <linux/tpm.h>
 
 #define TCG_EVENT_NAME_LEN_MAX	255
 #define MAX_TEXT_EVENT		1000	/* Max event string length */
@@ -105,16 +105,11 @@ struct tcg_event_field {
 	u8 event[0];
 } __packed;
 
-struct tpm2_digest {
-	u16 alg_id;
-	u8 digest[SHA512_DIGEST_SIZE];
-} __packed;
-
 struct tcg_pcr_event2_head {
 	u32 pcr_idx;
 	u32 event_type;
 	u32 count;
-	struct tpm2_digest digests[0];
+	struct tpm_digest digests[0];
 } __packed;
 
 #endif
-- 
2.17.1

[PATCH v6 4/7] tpm: modify tpm_pcr_read() definition to pass a TPM hash algorithm

[Roberto Sassu]

Currently the TPM driver allows other kernel subsystems to read only the
SHA1 PCR bank. This patch modifies the parameters of tpm_pcr_read() and
tpm2_pcr_read() to pass a tpm_digest structure, which contains the desired
hash algorithm. Also, since commit 125a22105410 ("tpm: React correctly to
RC_TESTING from TPM 2.0 self tests") removed the call to tpm2_pcr_read(),
the new parameter is expected to be always not NULL.

Due to the API change, IMA functions have been modified.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
---
 drivers/char/tpm/tpm-interface.c    |  9 +++++----
 drivers/char/tpm/tpm.h              |  3 ++-
 drivers/char/tpm/tpm2-cmd.c         | 23 ++++++++++++++++-------
 include/linux/tpm.h                 |  6 ++++--
 security/integrity/ima/ima_crypto.c | 10 +++++-----
 5 files changed, 32 insertions(+), 19 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 96c8261d0f04..cea4c8d75ad0 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -451,11 +451,12 @@ EXPORT_SYMBOL_GPL(tpm_is_tpm2);
  * tpm_pcr_read - read a PCR value from SHA1 bank
  * @chip:	a &struct tpm_chip instance, %NULL for the default chip
  * @pcr_idx:	the PCR to be retrieved
- * @res_buf:	the value of the PCR
+ * @digest:	the PCR bank and buffer current PCR value is written to
  *
  * Return: same as with tpm_transmit_cmd()
  */
-int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
+int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
+		 struct tpm_digest *digest)
 {
 	int rc;
 
@@ -464,9 +465,9 @@ int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
 		return -ENODEV;
 
 	if (chip->flags & TPM_CHIP_FLAG_TPM2)
-		rc = tpm2_pcr_read(chip, pcr_idx, res_buf);
+		rc = tpm2_pcr_read(chip, pcr_idx, digest);
 	else
-		rc = tpm1_pcr_read(chip, pcr_idx, res_buf);
+		rc = tpm1_pcr_read(chip, pcr_idx, digest->digest);
 
 	tpm_put_ops(chip);
 	return rc;
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index e961e5c5d197..343aa58424f7 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -548,7 +548,8 @@ static inline u32 tpm2_rc_value(u32 rc)
 }
 
 int tpm2_get_timeouts(struct tpm_chip *chip);
-int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf);
+int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
+		  struct tpm_digest *digest);
 int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
 		    struct tpm_digest *digests);
 int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max);
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 4afd14892cbf..81740d55f19c 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -171,16 +171,18 @@ struct tpm2_pcr_read_out {
  * tpm2_pcr_read() - read a PCR value
  * @chip:	TPM chip to use.
  * @pcr_idx:	index of the PCR to read.
- * @res_buf:	buffer to store the resulting hash.
+ * @digest:	PCR bank and buffer current PCR value is written to.
  *
  * Return: Same as with tpm_transmit_cmd.
  */
-int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
+int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
+		  struct tpm_digest *digest)
 {
 	int rc;
 	struct tpm_buf buf;
 	struct tpm2_pcr_read_out *out;
 	u8 pcr_select[TPM2_PCR_SELECT_MIN] = {0};
+	u16 digest_size;
 
 	if (pcr_idx >= TPM2_PLATFORM_PCR)
 		return -EINVAL;
@@ -192,18 +194,25 @@ int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
 	pcr_select[pcr_idx >> 3] = 1 << (pcr_idx & 0x7);
 
 	tpm_buf_append_u32(&buf, 1);
-	tpm_buf_append_u16(&buf, TPM_ALG_SHA1);
+	tpm_buf_append_u16(&buf, digest->alg_id);
 	tpm_buf_append_u8(&buf, TPM2_PCR_SELECT_MIN);
 	tpm_buf_append(&buf, (const unsigned char *)pcr_select,
 		       sizeof(pcr_select));
 
 	rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 0, 0,
-			res_buf ? "attempting to read a pcr value" : NULL);
-	if (rc == 0 && res_buf) {
-		out = (struct tpm2_pcr_read_out *)&buf.data[TPM_HEADER_SIZE];
-		memcpy(res_buf, out->digest, SHA1_DIGEST_SIZE);
+			      "attempting to read a pcr value");
+	if (rc)
+		goto out;
+
+	out = (struct tpm2_pcr_read_out *)&buf.data[TPM_HEADER_SIZE];
+	digest_size = be16_to_cpu(out->digest_size);
+	if (digest_size > sizeof(digest->digest)) {
+		rc = -EINVAL;
+		goto out;
 	}
 
+	memcpy(digest->digest, out->digest, digest_size);
+out:
 	tpm_buf_destroy(&buf);
 	return rc;
 }
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 330c0a481581..95e11688826e 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -71,7 +71,8 @@ struct tpm_class_ops {
 #if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)
 
 extern int tpm_is_tpm2(struct tpm_chip *chip);
-extern int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf);
+extern int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
+			struct tpm_digest *digest);
 extern int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash);
 extern int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen);
 extern int tpm_get_random(struct tpm_chip *chip, u8 *data, size_t max);
@@ -88,7 +89,8 @@ static inline int tpm_is_tpm2(struct tpm_chip *chip)
 	return -ENODEV;
 }
 
-static inline int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf)
+static inline int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx,
+			       struct tpm_digest *digest)
 {
 	return -ENODEV;
 }
diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index acf2c7df7145..16a4f45863b1 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -643,12 +643,12 @@ int ima_calc_buffer_hash(const void *buf, loff_t len,
 	return calc_buffer_shash(buf, len, hash);
 }
 
-static void __init ima_pcrread(u32 idx, u8 *pcr)
+static void __init ima_pcrread(u32 idx, struct tpm_digest *d)
 {
 	if (!ima_tpm_chip)
 		return;
 
-	if (tpm_pcr_read(ima_tpm_chip, idx, pcr) != 0)
+	if (tpm_pcr_read(ima_tpm_chip, idx, d) != 0)
 		pr_err("Error Communicating to TPM chip\n");
 }
 
@@ -658,7 +658,7 @@ static void __init ima_pcrread(u32 idx, u8 *pcr)
 static int __init ima_calc_boot_aggregate_tfm(char *digest,
 					      struct crypto_shash *tfm)
 {
-	u8 pcr_i[TPM_DIGEST_SIZE];
+	struct tpm_digest d = { .alg_id = TPM_ALG_SHA1, .digest = {0} };
 	int rc;
 	u32 i;
 	SHASH_DESC_ON_STACK(shash, tfm);
@@ -672,9 +672,9 @@ static int __init ima_calc_boot_aggregate_tfm(char *digest,
 
 	/* cumulative sha1 over tpm registers 0-7 */
 	for (i = TPM_PCR0; i < TPM_PCR8; i++) {
-		ima_pcrread(i, pcr_i);
+		ima_pcrread(i, &d);
 		/* now accumulate with current aggregate */
-		rc = crypto_shash_update(shash, pcr_i, TPM_DIGEST_SIZE);
+		rc = crypto_shash_update(shash, d.digest, TPM_DIGEST_SIZE);
 	}
 	if (!rc)
 		crypto_shash_final(shash, digest);
-- 
2.17.1

[PATCH v6 5/7] tpm: retrieve digest size of unknown algorithms with PCR read

[Roberto Sassu]

Currently, the TPM driver retrieves the digest size from a table mapping
TPM algorithms identifiers to identifiers defined by the crypto subsystem.
If the algorithm is not defined by the latter, the digest size can be
retrieved from the output of the PCR read command.

The patch retrieves at TPM startup the digest sizes for each PCR bank and
stores them in the new structure tpm_bank_info, member of tpm_chip, so that
the information can be passed to other kernel subsystems.

tpm_bank_info contains: the TPM algorithm identifier, necessary to generate
the event log as defined by Trusted Computing Group (TCG); the digest size,
to pad/truncate a digest calculated with a different algorithm; the crypto
subsystem identifier, to calculate the digest of event data.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
---
 drivers/char/tpm/tpm-interface.c |  9 +++----
 drivers/char/tpm/tpm.h           |  4 +--
 drivers/char/tpm/tpm1-cmd.c      |  4 ++-
 drivers/char/tpm/tpm2-cmd.c      | 45 ++++++++++++++++++++++++--------
 include/linux/tpm.h              |  6 +++++
 5 files changed, 49 insertions(+), 19 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index cea4c8d75ad0..eb7c79ca8a94 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -465,7 +465,7 @@ int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
 		return -ENODEV;
 
 	if (chip->flags & TPM_CHIP_FLAG_TPM2)
-		rc = tpm2_pcr_read(chip, pcr_idx, digest);
+		rc = tpm2_pcr_read(chip, pcr_idx, digest, NULL);
 	else
 		rc = tpm1_pcr_read(chip, pcr_idx, digest->digest);
 
@@ -480,9 +480,8 @@ EXPORT_SYMBOL_GPL(tpm_pcr_read);
  * @pcr_idx:	the PCR to be retrieved
  * @hash:	the hash value used to extend the PCR value
  *
- * Note: with TPM 2.0 extends also those banks with a known digest size to the
- * cryto subsystem in order to prevent malicious use of those PCR banks. In the
- * future we should dynamically determine digest sizes.
+ * Note: with TPM 2.0 extends also those banks for which no digest was
+ * specified in order to prevent malicious use of those PCR banks.
  *
  * Return: same as with tpm_transmit_cmd()
  */
@@ -503,7 +502,7 @@ int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash)
 			return -ENOMEM;
 
 		for (i = 0; i < chip->nr_allocated_banks; i++) {
-			digest_list[i].alg_id = chip->allocated_banks[i];
+			digest_list[i].alg_id = chip->allocated_banks[i].alg_id;
 			memcpy(digest_list[i].digest, hash, TPM_DIGEST_SIZE);
 		}
 
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 343aa58424f7..64d93d26087f 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -247,7 +247,7 @@ struct tpm_chip {
 	unsigned int groups_cnt;
 
 	u32 nr_allocated_banks;
-	u16 *allocated_banks;
+	struct tpm_bank_info *allocated_banks;
 #ifdef CONFIG_ACPI
 	acpi_handle acpi_dev_handle;
 	char ppi_version[TPM_PPI_VERSION_LEN + 1];
@@ -549,7 +549,7 @@ static inline u32 tpm2_rc_value(u32 rc)
 
 int tpm2_get_timeouts(struct tpm_chip *chip);
 int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
-		  struct tpm_digest *digest);
+		  struct tpm_digest *digest, u16 *digest_size_ptr);
 int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
 		    struct tpm_digest *digests);
 int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max);
diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
index ec4f197bae0a..8b70a7f884a7 100644
--- a/drivers/char/tpm/tpm1-cmd.c
+++ b/drivers/char/tpm/tpm1-cmd.c
@@ -716,7 +716,9 @@ int tpm1_auto_startup(struct tpm_chip *chip)
 		goto out;
 	}
 
-	chip->allocated_banks[0] = TPM_ALG_SHA1;
+	chip->allocated_banks[0].alg_id = TPM_ALG_SHA1;
+	chip->allocated_banks[0].digest_size = hash_digest_size[HASH_ALGO_SHA1];
+	chip->allocated_banks[0].crypto_id = HASH_ALGO_SHA1;
 	chip->nr_allocated_banks = 1;
 
 	return rc;
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 81740d55f19c..a804f0b7126a 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -172,11 +172,12 @@ struct tpm2_pcr_read_out {
  * @chip:	TPM chip to use.
  * @pcr_idx:	index of the PCR to read.
  * @digest:	PCR bank and buffer current PCR value is written to.
+ * @digest_size_ptr:	pointer to variable that stores the digest size.
  *
  * Return: Same as with tpm_transmit_cmd.
  */
 int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
-		  struct tpm_digest *digest)
+		  struct tpm_digest *digest, u16 *digest_size_ptr)
 {
 	int rc;
 	struct tpm_buf buf;
@@ -211,6 +212,9 @@ int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
 		goto out;
 	}
 
+	if (digest_size_ptr)
+		*digest_size_ptr = digest_size;
+
 	memcpy(digest->digest, out->digest, digest_size);
 out:
 	tpm_buf_destroy(&buf);
@@ -241,7 +245,6 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
 	struct tpm2_null_auth_area auth_area;
 	int rc;
 	int i;
-	int j;
 
 	if (count > chip->nr_allocated_banks)
 		return -EINVAL;
@@ -263,14 +266,9 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
 	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]);
-		}
+		tpm_buf_append_u16(&buf, digests[i].alg_id);
+		tpm_buf_append(&buf, (const unsigned char *)&digests[i].digest,
+			       chip->allocated_banks[i].digest_size);
 	}
 
 	rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 0, 0,
@@ -821,6 +819,26 @@ int tpm2_probe(struct tpm_chip *chip)
 }
 EXPORT_SYMBOL_GPL(tpm2_probe);
 
+static int tpm2_init_bank_info(struct tpm_chip *chip, u32 bank_index)
+{
+	struct tpm_bank_info *bank = chip->allocated_banks + bank_index;
+	struct tpm_digest digest = { .alg_id = bank->alg_id };
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) {
+		enum hash_algo crypto_algo = tpm2_hash_map[i].crypto_id;
+
+		if (bank->alg_id != tpm2_hash_map[i].tpm_id)
+			continue;
+
+		bank->digest_size = hash_digest_size[crypto_algo];
+		bank->crypto_id = crypto_algo;
+		return 0;
+	}
+
+	return tpm2_pcr_read(chip, 0, &digest, &bank->digest_size);
+}
+
 struct tpm2_pcr_selection {
 	__be16  hash_alg;
 	u8  size_of_select;
@@ -888,7 +906,12 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
 				break;
 
 		if (j < pcr_selection.size_of_select) {
-			chip->allocated_banks[nr_alloc_banks] = hash_alg;
+			chip->allocated_banks[nr_alloc_banks].alg_id = hash_alg;
+
+			rc = tpm2_init_bank_info(chip, nr_alloc_banks);
+			if (rc < 0)
+				break;
+
 			nr_alloc_banks++;
 		}
 
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 95e11688826e..72df8d4252ef 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -46,6 +46,12 @@ struct tpm_digest {
 	u8 digest[SHA512_DIGEST_SIZE];
 } __packed;
 
+struct tpm_bank_info {
+	u16 alg_id;
+	u16 digest_size;
+	u16 crypto_id;
+};
+
 enum TPM_OPS_FLAGS {
 	TPM_OPS_AUTO_STARTUP = BIT(0),
 };
-- 
2.17.1

[PATCH v6 6/7] tpm: ensure that the output of PCR read contains the correct digest size

[Roberto Sassu]

This patch protects against data corruption that could happen in the bus,
by checking that the digest size returned by the TPM during a PCR read
matches the size of the algorithm passed to tpm2_pcr_read().

This check is performed after information about the PCR banks has been
retrieved.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 drivers/char/tpm/tpm2-cmd.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index a804f0b7126a..d6d29480348c 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -179,15 +179,28 @@ struct tpm2_pcr_read_out {
 int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
 		  struct tpm_digest *digest, u16 *digest_size_ptr)
 {
+	int i;
 	int rc;
 	struct tpm_buf buf;
 	struct tpm2_pcr_read_out *out;
 	u8 pcr_select[TPM2_PCR_SELECT_MIN] = {0};
 	u16 digest_size;
+	u16 expected_digest_size = 0;
 
 	if (pcr_idx >= TPM2_PLATFORM_PCR)
 		return -EINVAL;
 
+	if (!digest_size_ptr) {
+		for (i = 0; i < chip->nr_allocated_banks &&
+		     chip->allocated_banks[i].alg_id != digest->alg_id; i++)
+			;
+
+		if (i == chip->nr_allocated_banks)
+			return -EINVAL;
+
+		expected_digest_size = chip->allocated_banks[i].digest_size;
+	}
+
 	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_PCR_READ);
 	if (rc)
 		return rc;
@@ -207,7 +220,8 @@ int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
 
 	out = (struct tpm2_pcr_read_out *)&buf.data[TPM_HEADER_SIZE];
 	digest_size = be16_to_cpu(out->digest_size);
-	if (digest_size > sizeof(digest->digest)) {
+	if (digest_size > sizeof(digest->digest) ||
+	    (!digest_size_ptr && digest_size != expected_digest_size)) {
 		rc = -EINVAL;
 		goto out;
 	}
-- 
2.17.1

[PATCH v6 7/7] tpm: pass an array of tpm_bank_list structures to tpm_pcr_extend()

[Roberto Sassu]

Currently, tpm_pcr_extend() accepts as an input only a SHA1 digest.

This patch modifies the definition of tpm_pcr_extend() to allow other
kernel subsystems to pass a digest for each algorithm supported by the TPM.
All digests are processed by the TPM in one operation.

If a tpm_pcr_extend() caller provides a subset of the supported algorithms,
the TPM driver extends the remaining PCR banks with the first digest
passed as an argument to the function.

The new tpm_bank_list structure has been preferred to the tpm_digest
structure, to let the caller specify the size of the digest (which may be
unknown to the TPM driver).

Due to the API change, ima_pcr_extend() and pcrlock() have been modified.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
 drivers/char/tpm/tpm-interface.c   | 24 +++++---------------
 drivers/char/tpm/tpm.h             |  6 ++---
 drivers/char/tpm/tpm1-cmd.c        | 14 ++++++++----
 drivers/char/tpm/tpm2-cmd.c        | 36 +++++++++++++++++++++---------
 include/linux/tpm.h                | 13 ++++++++---
 security/integrity/ima/ima_queue.c |  5 ++++-
 security/keys/trusted.c            |  5 ++++-
 7 files changed, 63 insertions(+), 40 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index eb7c79ca8a94..36e00adaf509 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -478,42 +478,30 @@ EXPORT_SYMBOL_GPL(tpm_pcr_read);
  * tpm_pcr_extend - extend a PCR value in SHA1 bank.
  * @chip:	a &struct tpm_chip instance, %NULL for the default chip
  * @pcr_idx:	the PCR to be retrieved
- * @hash:	the hash value used to extend the PCR value
+ * @count:	number of tpm_bank_list structures
+ * @bank_list:	array of tpm_bank_list structures used to extend the PCR value
  *
  * Note: with TPM 2.0 extends also those banks for which no digest was
  * specified in order to prevent malicious use of those PCR banks.
  *
  * Return: same as with tpm_transmit_cmd()
  */
-int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash)
+int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
+		   const struct tpm_bank_list *bank_list)
 {
 	int rc;
-	struct tpm_digest *digest_list;
-	int i;
 
 	chip = tpm_find_get_ops(chip);
 	if (!chip)
 		return -ENODEV;
 
 	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
-		digest_list = kcalloc(chip->nr_allocated_banks,
-				      sizeof(*digest_list), GFP_KERNEL);
-		if (!digest_list)
-			return -ENOMEM;
-
-		for (i = 0; i < chip->nr_allocated_banks; i++) {
-			digest_list[i].alg_id = chip->allocated_banks[i].alg_id;
-			memcpy(digest_list[i].digest, hash, TPM_DIGEST_SIZE);
-		}
-
-		rc = tpm2_pcr_extend(chip, pcr_idx, chip->nr_allocated_banks,
-				     digest_list);
-		kfree(digest_list);
+		rc = tpm2_pcr_extend(chip, pcr_idx, count, bank_list);
 		tpm_put_ops(chip);
 		return rc;
 	}
 
-	rc = tpm1_pcr_extend(chip, pcr_idx, hash,
+	rc = tpm1_pcr_extend(chip, pcr_idx, count, bank_list,
 			     "attempting extend a PCR value");
 	tpm_put_ops(chip);
 	return rc;
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 64d93d26087f..f0cae0892c4e 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -504,8 +504,8 @@ int tpm1_auto_startup(struct tpm_chip *chip);
 int tpm1_do_selftest(struct tpm_chip *chip);
 int tpm1_get_timeouts(struct tpm_chip *chip);
 unsigned long tpm1_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal);
-int tpm1_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash,
-		    const char *log_msg);
+int tpm1_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
+		    const struct tpm_bank_list *bank_list, const char *log_msg);
 int tpm1_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf);
 ssize_t tpm1_getcap(struct tpm_chip *chip, u32 subcap_id, cap_t *cap,
 		    const char *desc, size_t min_cap_length);
@@ -551,7 +551,7 @@ int tpm2_get_timeouts(struct tpm_chip *chip);
 int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
 		  struct tpm_digest *digest, u16 *digest_size_ptr);
 int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
-		    struct tpm_digest *digests);
+		    const struct tpm_bank_list *bank_list);
 int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max);
 void tpm2_flush_context_cmd(struct tpm_chip *chip, u32 handle,
 			    unsigned int flags);
diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
index 8b70a7f884a7..984bacb1a52f 100644
--- a/drivers/char/tpm/tpm1-cmd.c
+++ b/drivers/char/tpm/tpm1-cmd.c
@@ -449,12 +449,19 @@ int tpm1_get_timeouts(struct tpm_chip *chip)
 }
 
 #define TPM_ORD_PCR_EXTEND 20
-int tpm1_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash,
-		    const char *log_msg)
+int tpm1_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
+		    const struct tpm_bank_list *bank_list, const char *log_msg)
 {
 	struct tpm_buf buf;
+	u8 dummy_hash[TPM_DIGEST_SIZE] = { 0 };
+	const u8 *hash;
 	int rc;
 
+	hash = dummy_hash;
+	if (count)
+		memcpy(dummy_hash, bank_list[0].extend_array,
+		       min(bank_list[0].extend_size, (u16)sizeof(dummy_hash)));
+
 	rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND, TPM_ORD_PCR_EXTEND);
 	if (rc)
 		return rc;
@@ -743,7 +750,6 @@ int tpm1_auto_startup(struct tpm_chip *chip)
  */
 int tpm1_pm_suspend(struct tpm_chip *chip, u32 tpm_suspend_pcr)
 {
-	u8 dummy_hash[TPM_DIGEST_SIZE] = { 0 };
 	struct tpm_buf buf;
 	unsigned int try;
 	int rc;
@@ -751,7 +757,7 @@ int tpm1_pm_suspend(struct tpm_chip *chip, u32 tpm_suspend_pcr)
 
 	/* for buggy tpm, flush pcrs with extend to selected dummy */
 	if (tpm_suspend_pcr)
-		rc = tpm1_pcr_extend(chip, tpm_suspend_pcr, dummy_hash,
+		rc = tpm1_pcr_extend(chip, tpm_suspend_pcr, 0, NULL,
 				     "extending dummy pcr before suspend");
 
 	rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND, TPM_ORD_SAVESTATE);
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index d6d29480348c..5186277cd981 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -247,21 +247,22 @@ struct tpm2_null_auth_area {
  *
  * @chip:	TPM chip to use.
  * @pcr_idx:	index of the PCR.
- * @count:	number of digests passed.
- * @digests:	list of pcr banks and corresponding digest values to extend.
+ * @count:	number of tpm_bank_list passed.
+ * @bank_list:	array of tpm_bank_list with digest values to extend.
  *
  * Return: Same as with tpm_transmit_cmd.
  */
 int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
-		    struct tpm_digest *digests)
+		    const struct tpm_bank_list *bank_list)
 {
 	struct tpm_buf buf;
 	struct tpm2_null_auth_area auth_area;
+	const struct tpm_bank_list *item;
+	u8 dummy_hash[SHA512_DIGEST_SIZE] = { 0 };
+	const u8 *hash;
 	int rc;
 	int i;
-
-	if (count > chip->nr_allocated_banks)
-		return -EINVAL;
+	int j;
 
 	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_PCR_EXTEND);
 	if (rc)
@@ -277,11 +278,26 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
 	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);
+	tpm_buf_append_u32(&buf, chip->nr_allocated_banks);
+
+	if (count)
+		memcpy(dummy_hash, bank_list[0].extend_array,
+		       bank_list[0].extend_size);
+
+	for (i = 0; i < chip->nr_allocated_banks; i++) {
+		tpm_buf_append_u16(&buf, chip->allocated_banks[i].alg_id);
+
+		hash = dummy_hash;
+		for (j = 0; j < count; j++) {
+			item = bank_list + j;
+
+			if (item->alg_id == chip->allocated_banks[i].alg_id) {
+				hash = item->extend_array;
+				break;
+			}
+		}
 
-	for (i = 0; i < count; i++) {
-		tpm_buf_append_u16(&buf, digests[i].alg_id);
-		tpm_buf_append(&buf, (const unsigned char *)&digests[i].digest,
+		tpm_buf_append(&buf, hash,
 			       chip->allocated_banks[i].digest_size);
 	}
 
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 72df8d4252ef..1b769e558452 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -52,6 +52,12 @@ struct tpm_bank_info {
 	u16 crypto_id;
 };
 
+struct tpm_bank_list {
+	u16 alg_id;
+	u16 extend_size;
+	const u8 *extend_array;
+};
+
 enum TPM_OPS_FLAGS {
 	TPM_OPS_AUTO_STARTUP = BIT(0),
 };
@@ -79,7 +85,8 @@ struct tpm_class_ops {
 extern int tpm_is_tpm2(struct tpm_chip *chip);
 extern int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
 			struct tpm_digest *digest);
-extern int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash);
+extern int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
+			  const struct tpm_bank_list *bank_list);
 extern int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen);
 extern int tpm_get_random(struct tpm_chip *chip, u8 *data, size_t max);
 extern int tpm_seal_trusted(struct tpm_chip *chip,
@@ -101,8 +108,8 @@ static inline int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx,
 	return -ENODEV;
 }
 
-static inline int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
-				 const u8 *hash)
+static inline int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
+				 const struct tpm_bank_list *bank_list)
 {
 	return -ENODEV;
 }
diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
index b186819bd5aa..07c5e26666df 100644
--- a/security/integrity/ima/ima_queue.c
+++ b/security/integrity/ima/ima_queue.c
@@ -140,12 +140,15 @@ unsigned long ima_get_binary_runtime_size(void)
 
 static int ima_pcr_extend(const u8 *hash, int pcr)
 {
+	struct tpm_bank_list bank_item = { .alg_id = TPM_ALG_SHA1,
+					   .extend_size = TPM_DIGEST_SIZE,
+					   .extend_array = hash };
 	int result = 0;
 
 	if (!ima_tpm_chip)
 		return result;
 
-	result = tpm_pcr_extend(ima_tpm_chip, pcr, hash);
+	result = tpm_pcr_extend(ima_tpm_chip, pcr, 1, &bank_item);
 	if (result != 0)
 		pr_err("Error Communicating to TPM chip, result: %d\n", result);
 	return result;
diff --git a/security/keys/trusted.c b/security/keys/trusted.c
index ff6789365a12..c7d8e6eac4f6 100644
--- a/security/keys/trusted.c
+++ b/security/keys/trusted.c
@@ -380,6 +380,9 @@ EXPORT_SYMBOL_GPL(trusted_tpm_send);
 static int pcrlock(const int pcrnum)
 {
 	unsigned char hash[SHA1_DIGEST_SIZE];
+	struct tpm_bank_list bank_item = { .alg_id = TPM_ALG_SHA1,
+					   .extend_size = sizeof(hash),
+					   .extend_array = hash };
 	int ret;
 
 	if (!capable(CAP_SYS_ADMIN))
@@ -387,7 +390,7 @@ static int pcrlock(const int pcrnum)
 	ret = tpm_get_random(NULL, hash, SHA1_DIGEST_SIZE);
 	if (ret != SHA1_DIGEST_SIZE)
 		return ret;
-	return tpm_pcr_extend(NULL, pcrnum, hash) ? -EINVAL : 0;
+	return tpm_pcr_extend(NULL, pcrnum, 1, &bank_item) ? -EINVAL : 0;
 }
 
 /*
-- 
2.17.1

Re: [PATCH v6 1/7] tpm: dynamically allocate the allocated_banks array

[Jarkko Sakkinen]

On Tue, Dec 04, 2018 at 09:21:32AM +0100, Roberto Sassu wrote:
> tpm2_get_pcr_allocation() determines if a PCR bank is allocated by checking
> the mask in the TPML_PCR_SELECTION structure returned by the TPM for
> TPM2_Get_Capability(). One PCR bank with algorithm set to SHA1 is always
> allocated for TPM 1.x.

...

> +		for (j = 0; j < pcr_selection.size_of_select; j++)
> +			if (pcr_selection.pcr_select[j])
> +				break;
> +
> +		if (j < pcr_selection.size_of_select) {
> +			chip->allocated_banks[nr_alloc_banks] = hash_alg;
> +			nr_alloc_banks++;
> +		}
> +

Why was this needed? Can CAP_PCRS return completely unallocated banks?

Kind of out-of-context for the rest of the changes.

Should this be a bug fix of its own because it looks like as this is a
bug fix for existing code, and not a new feature? Just asking because
I don't yet fully understand this change.

Anyway, I believe that you can streamline this by:

/* Check that at least some of the PCRs have been allocated. This is
 * required because CAP_PCRS ...
 */
if (memchr_inv(pcr_selection.pcr_select, 0, pcr_selection.size_of_select))
	nr_allocated_banks++;

[yeah, comment would be awesome about CAP_PCRS. Did not finish up the
comment because I don't know the answer]

In addition, it would be consistent to call the local variable also
nr_allocated_banks (not nr_alloc_banks).

/Jarkko

Re: [PATCH v6 2/7] tpm: add _head suffix to tcg_efi_specid_event and tcg_pcr_event2

[Jarkko Sakkinen]

On Tue, Dec 04, 2018 at 09:21:33AM +0100, Roberto Sassu wrote:
> TCG defines two structures, TCG_EfiSpecIDEventStruct and TCG_PCR_EVENT2,
> which contain variable-sized arrays in the middle of the definition.
> 
> Since these structures are not suitable for type casting, this patch
> removes structure members after the variable-sized arrays and adds the
> _head suffix to the structure name, to indicate that the renamed structures
> do not contain all fields defined by TCG.
> 
> Lastly, given that variable-sized arrays are now in the last position, and
> given that the size of the arrays cannot be determined in advance, this
> patch also sets the size of those arrays to zero and removes the definition
> of TPM2_ACTIVE_PCR_BANKS.
> 
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>

Thank you, brings up a lot of clarity.

Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

/Jarkko

Re: [PATCH v6 4/7] tpm: modify tpm_pcr_read() definition to pass a TPM hash algorithm

[Jarkko Sakkinen]

On Tue, Dec 04, 2018 at 09:21:35AM +0100, Roberto Sassu wrote:
> Currently the TPM driver allows other kernel subsystems to read only the
> SHA1 PCR bank. This patch modifies the parameters of tpm_pcr_read() and
> tpm2_pcr_read() to pass a tpm_digest structure, which contains the desired
> hash algorithm. Also, since commit 125a22105410 ("tpm: React correctly to
> RC_TESTING from TPM 2.0 self tests") removed the call to tpm2_pcr_read(),
> the new parameter is expected to be always not NULL.
> 
> Due to the API change, IMA functions have been modified.
> 
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> Acked-by: Mimi Zohar <zohar@linux.ibm.com>

Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

Mimi, Nayna, can you help with testing this (because of the IMA change)?

/Jarkko

Re: [PATCH v6 5/7] tpm: retrieve digest size of unknown algorithms with PCR read

[Jarkko Sakkinen]

On Tue, Dec 04, 2018 at 09:21:36AM +0100, Roberto Sassu wrote:
> +	for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) {
> +		enum hash_algo crypto_algo = tpm2_hash_map[i].crypto_id;
> +
> +		if (bank->alg_id != tpm2_hash_map[i].tpm_id)
> +			continue;
> +
> +		bank->digest_size = hash_digest_size[crypto_algo];
> +		bank->crypto_id = crypto_algo;
> +		return 0;
> +	}
> +
> +	return tpm2_pcr_read(chip, 0, &digest, &bank->digest_size);
> +}

This is a part that I don't get. Coud you just always call
tpm2_pcr_read() instead of this complexity

/Jarkko

Re: [PATCH v6 6/7] tpm: ensure that the output of PCR read contains the correct digest size

[Jarkko Sakkinen]

On Tue, Dec 04, 2018 at 09:21:37AM +0100, Roberto Sassu wrote:
>  	out = (struct tpm2_pcr_read_out *)&buf.data[TPM_HEADER_SIZE];
>  	digest_size = be16_to_cpu(out->digest_size);
> -	if (digest_size > sizeof(digest->digest)) {
> +	if (digest_size > sizeof(digest->digest) ||
> +	    (!digest_size_ptr && digest_size != expected_digest_size)) {
>  		rc = -EINVAL;
>  		goto out;
>  	}

Just noticed this but you must squash 4-6 because applying only
previous commits will result a broken tree. It will be much bigger
commit but won't be broken.

I think you should also feed min_rsp_body_length as you should be
able to precalculate.

Last time I was asking why this isn't a bug fix. It is even for
the existing code. The existing code should have a bug fix that
checks that the received digest size so that it is the expected
SHA1 size before we can apply this commit.

/Jarkko

Re: [PATCH v6 7/7] tpm: pass an array of tpm_bank_list structures to tpm_pcr_extend()

[Jarkko Sakkinen]

On Tue, Dec 04, 2018 at 09:21:38AM +0100, Roberto Sassu wrote:
> The new tpm_bank_list structure has been preferred to the tpm_digest
> structure, to let the caller specify the size of the digest (which may be
> unknown to the TPM driver).

Why is that? Didn't previous commit query these?

> +struct tpm_bank_list {
> +	u16 alg_id;
> +	u16 extend_size;
> +	const u8 *extend_array;
> +};

Naming is not good here. If this only for extending shouldn't that
be in the structs name?

/Jarkko

Re: [PATCH v6 0/7] tpm: retrieve digest size of unknown algorithms from TPM

[Jarkko Sakkinen]

On Tue, Dec 04, 2018 at 09:21:31AM +0100, Roberto Sassu wrote:
> Update
> 
> This version of the patch set includes an additional patch (7/7) which
> modifies the definition of tpm_pcr_extend() and tpm2_pcr_extend(). The new
> patch has been included to facilitate the review of the changes to support
> TPM 2.0 crypto agility for reading/extending PCRs.
> 
> 
> Original patch set description
> 
> The TPM driver currently relies on the crypto subsystem to determine the
> digest size of supported TPM algorithms. In the future, TPM vendors might
> implement new algorithms in their chips, and those algorithms might not
> be supported by the crypto subsystem.
> 
> Usually, vendors provide patches for the new hardware, and likely
> the crypto subsystem will be updated before the new algorithm is
> introduced. However, old kernels might be updated later, after patches
> are included in the mainline kernel. This would leave the opportunity
> for attackers to misuse PCRs, as PCR banks with an unknown algorithm
> are not extended.
> 
> This patch set provides a long term solution for this issue. If a TPM
> algorithm is not known by the crypto subsystem, the TPM driver retrieves
> the digest size from the TPM with a PCR read. All the PCR banks are
> extended, even if the algorithm is not yet supported by the crypto
> subsystem.
> 
> PCR bank information (TPM algorithm ID, digest size, crypto subsystem ID)
> is stored in the tpm_chip structure and available for users of the TPM
> driver.
> 
> Changelog
> 
> v5:
> - rename digest_struct variable to digest
> - add _head suffix to tcg_efi_specid_event and tcg_pcr_event2
> - rename digest_size member of tpm_bank_list to extend_size
> - change type of alg_id member of tpm_bank list from u8 to u16
> - add missing semi-colon in pcrlock()
> 
> v4:
> - rename active_banks to allocated_banks
> - replace kmalloc_array() with kcalloc()
> - increment nr_allocated_banks if at least one PCR in the bank is selected
> - pass multiple digests to tpm_pcr_extend()
> 
> v3:
> - remove end marker change
> - replace active_banks static array with pointer to dynamic array
> - remove TPM2_ACTIVE_PCR_BANKS
> 
> v2:
> - change the end marker of the active_banks array
> - check digest size from output of PCR read command
> - remove count parameter from tpm_pcr_read() and tpm2_pcr_read()
> 
> v1:
> - modify definition of tpm_pcr_read()
> - move hash algorithms and definition of tpm2_digest to include/linux/tpm.h
> 
> Roberto Sassu (7):
>   tpm: dynamically allocate the allocated_banks array
>   tpm: add _head suffix to tcg_efi_specid_event and tcg_pcr_event2
>   tpm: rename and export tpm2_digest and tpm2_algorithms
>   tpm: modify tpm_pcr_read() definition to pass a TPM hash algorithm
>   tpm: retrieve digest size of unknown algorithms with PCR read
>   tpm: ensure that the output of PCR read contains the correct digest
>     size
>   tpm: pass an array of tpm_bank_list structures to tpm_pcr_extend()
> 
>  drivers/char/tpm/eventlog/tpm2.c    |  12 +--
>  drivers/char/tpm/tpm-chip.c         |   1 +
>  drivers/char/tpm/tpm-interface.c    |  36 +++----
>  drivers/char/tpm/tpm.h              |  23 ++---
>  drivers/char/tpm/tpm1-cmd.c         |  26 ++++-
>  drivers/char/tpm/tpm2-cmd.c         | 154 +++++++++++++++++++++-------
>  include/linux/tpm.h                 |  43 +++++++-
>  include/linux/tpm_eventlog.h        |  19 +---
>  security/integrity/ima/ima_crypto.c |  10 +-
>  security/integrity/ima/ima_queue.c  |   5 +-
>  security/keys/trusted.c             |   5 +-
>  11 files changed, 220 insertions(+), 114 deletions(-)
> 
> -- 
> 2.17.1
> 

Some generic stuff I noticed:

* Use SHA1_DIGEST_SIZE, not TPM_DIGEST_SIZE. The latter is just
  uninforming constant that we want to get rid off.

/Jarkko

Re: [PATCH v6 0/7] tpm: retrieve digest size of unknown algorithms from TPM

[Jarkko Sakkinen]

On Tue, Dec 04, 2018 at 04:21:55PM -0800, Jarkko Sakkinen wrote:
> On Tue, Dec 04, 2018 at 09:21:31AM +0100, Roberto Sassu wrote:
> > Update
> > 
> > This version of the patch set includes an additional patch (7/7) which
> > modifies the definition of tpm_pcr_extend() and tpm2_pcr_extend(). The new
> > patch has been included to facilitate the review of the changes to support
> > TPM 2.0 crypto agility for reading/extending PCRs.
> > 
> > 
> > Original patch set description
> > 
> > The TPM driver currently relies on the crypto subsystem to determine the
> > digest size of supported TPM algorithms. In the future, TPM vendors might
> > implement new algorithms in their chips, and those algorithms might not
> > be supported by the crypto subsystem.
> > 
> > Usually, vendors provide patches for the new hardware, and likely
> > the crypto subsystem will be updated before the new algorithm is
> > introduced. However, old kernels might be updated later, after patches
> > are included in the mainline kernel. This would leave the opportunity
> > for attackers to misuse PCRs, as PCR banks with an unknown algorithm
> > are not extended.
> > 
> > This patch set provides a long term solution for this issue. If a TPM
> > algorithm is not known by the crypto subsystem, the TPM driver retrieves
> > the digest size from the TPM with a PCR read. All the PCR banks are
> > extended, even if the algorithm is not yet supported by the crypto
> > subsystem.
> > 
> > PCR bank information (TPM algorithm ID, digest size, crypto subsystem ID)
> > is stored in the tpm_chip structure and available for users of the TPM
> > driver.
> > 
> > Changelog
> > 
> > v5:
> > - rename digest_struct variable to digest
> > - add _head suffix to tcg_efi_specid_event and tcg_pcr_event2
> > - rename digest_size member of tpm_bank_list to extend_size
> > - change type of alg_id member of tpm_bank list from u8 to u16
> > - add missing semi-colon in pcrlock()
> > 
> > v4:
> > - rename active_banks to allocated_banks
> > - replace kmalloc_array() with kcalloc()
> > - increment nr_allocated_banks if at least one PCR in the bank is selected
> > - pass multiple digests to tpm_pcr_extend()
> > 
> > v3:
> > - remove end marker change
> > - replace active_banks static array with pointer to dynamic array
> > - remove TPM2_ACTIVE_PCR_BANKS
> > 
> > v2:
> > - change the end marker of the active_banks array
> > - check digest size from output of PCR read command
> > - remove count parameter from tpm_pcr_read() and tpm2_pcr_read()
> > 
> > v1:
> > - modify definition of tpm_pcr_read()
> > - move hash algorithms and definition of tpm2_digest to include/linux/tpm.h
> > 
> > Roberto Sassu (7):
> >   tpm: dynamically allocate the allocated_banks array
> >   tpm: add _head suffix to tcg_efi_specid_event and tcg_pcr_event2
> >   tpm: rename and export tpm2_digest and tpm2_algorithms
> >   tpm: modify tpm_pcr_read() definition to pass a TPM hash algorithm
> >   tpm: retrieve digest size of unknown algorithms with PCR read
> >   tpm: ensure that the output of PCR read contains the correct digest
> >     size
> >   tpm: pass an array of tpm_bank_list structures to tpm_pcr_extend()
> > 
> >  drivers/char/tpm/eventlog/tpm2.c    |  12 +--
> >  drivers/char/tpm/tpm-chip.c         |   1 +
> >  drivers/char/tpm/tpm-interface.c    |  36 +++----
> >  drivers/char/tpm/tpm.h              |  23 ++---
> >  drivers/char/tpm/tpm1-cmd.c         |  26 ++++-
> >  drivers/char/tpm/tpm2-cmd.c         | 154 +++++++++++++++++++++-------
> >  include/linux/tpm.h                 |  43 +++++++-
> >  include/linux/tpm_eventlog.h        |  19 +---
> >  security/integrity/ima/ima_crypto.c |  10 +-
> >  security/integrity/ima/ima_queue.c  |   5 +-
> >  security/keys/trusted.c             |   5 +-
> >  11 files changed, 220 insertions(+), 114 deletions(-)
> > 
> > -- 
> > 2.17.1
> > 
> 
> Some generic stuff I noticed:
> 
> * Use SHA1_DIGEST_SIZE, not TPM_DIGEST_SIZE. The latter is just
>   uninforming constant that we want to get rid off.

Oops, sent by mistake. Other thing was that if you have an array
in the tail of the struct you can just have [] no subcript zero
needed.

/Jarkko

Re: [PATCH v6 6/7] tpm: ensure that the output of PCR read contains the correct digest size

[Jarkko Sakkinen]

On Tue, Dec 04, 2018 at 04:09:10PM -0800, Jarkko Sakkinen wrote:
> On Tue, Dec 04, 2018 at 09:21:37AM +0100, Roberto Sassu wrote:
> >  	out = (struct tpm2_pcr_read_out *)&buf.data[TPM_HEADER_SIZE];
> >  	digest_size = be16_to_cpu(out->digest_size);
> > -	if (digest_size > sizeof(digest->digest)) {
> > +	if (digest_size > sizeof(digest->digest) ||
> > +	    (!digest_size_ptr && digest_size != expected_digest_size)) {
> >  		rc = -EINVAL;
> >  		goto out;
> >  	}
> 
> Just noticed this but you must squash 4-6 because applying only
> previous commits will result a broken tree. It will be much bigger
> commit but won't be broken.
> 
> I think you should also feed min_rsp_body_length as you should be
> able to precalculate.
> 
> Last time I was asking why this isn't a bug fix. It is even for
> the existing code. The existing code should have a bug fix that
> checks that the received digest size so that it is the expected
> SHA1 size before we can apply this commit.

My bad. This is not the same deal as the code because in the old code we
always copy a constant block. Here we use the variable as parameter for
memcpy() so it is better to check the size. You can ignore the last
paragraph completely. Sorry, had to double check this one.

There is no need to do any type of bug fix for the current tree.

Still 4-6 need to be squashed in order to not put purposely the tree
into broken state.

/Jarko

Re: [PATCH v6 4/7] tpm: modify tpm_pcr_read() definition to pass a TPM hash algorithm

[Mimi Zohar]

On Tue, 2018-12-04 at 15:40 -0800, Jarkko Sakkinen wrote:
> On Tue, Dec 04, 2018 at 09:21:35AM +0100, Roberto Sassu wrote:
> > Currently the TPM driver allows other kernel subsystems to read only the
> > SHA1 PCR bank. This patch modifies the parameters of tpm_pcr_read() and
> > tpm2_pcr_read() to pass a tpm_digest structure, which contains the desired
> > hash algorithm. Also, since commit 125a22105410 ("tpm: React correctly to
> > RC_TESTING from TPM 2.0 self tests") removed the call to tpm2_pcr_read(),
> > the new parameter is expected to be always not NULL.
> > 
> > Due to the API change, IMA functions have been modified.
> > 
> > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> > Acked-by: Mimi Zohar <zohar@linux.ibm.com>
> 
> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> 
> Mimi, Nayna, can you help with testing this (because of the IMA change)?

It's up & running and the measurement list verifies against the TPM
PCR.  Although this system has two algorithms enabled, all of the PCRs
are allocated for one algorithm and none for the other.  I'm still
looking around for another system with PCR 10 enabled for multiple
algorithms.

Mimi

Re: [PATCH v6 4/7] tpm: modify tpm_pcr_read() definition to pass a TPM hash algorithm

[Nayna Jain]

On 12/05/2018 05:10 AM, Jarkko Sakkinen wrote:
> On Tue, Dec 04, 2018 at 09:21:35AM +0100, Roberto Sassu wrote:
>> Currently the TPM driver allows other kernel subsystems to read only the
>> SHA1 PCR bank. This patch modifies the parameters of tpm_pcr_read() and
>> tpm2_pcr_read() to pass a tpm_digest structure, which contains the desired
>> hash algorithm. Also, since commit 125a22105410 ("tpm: React correctly to
>> RC_TESTING from TPM 2.0 self tests") removed the call to tpm2_pcr_read(),
>> the new parameter is expected to be always not NULL.
>>
>> Due to the API change, IMA functions have been modified.
>>
>> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
>> Acked-by: Mimi Zohar <zohar@linux.ibm.com>
> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
>
> Mimi, Nayna, can you help with testing this (because of the IMA change)?

Sure, I will try to do by end of my day tomorrow,

Thanks & Regards,
     - Nayna

>
> /Jarkko
>

Re: [PATCH v6 1/7] tpm: dynamically allocate the allocated_banks array

[Roberto Sassu]

On 12/5/2018 12:18 AM, Jarkko Sakkinen wrote:
> On Tue, Dec 04, 2018 at 09:21:32AM +0100, Roberto Sassu wrote:
>> tpm2_get_pcr_allocation() determines if a PCR bank is allocated by checking
>> the mask in the TPML_PCR_SELECTION structure returned by the TPM for
>> TPM2_Get_Capability(). One PCR bank with algorithm set to SHA1 is always
>> allocated for TPM 1.x.
> 
> ...
> 
>> +		for (j = 0; j < pcr_selection.size_of_select; j++)
>> +			if (pcr_selection.pcr_select[j])
>> +				break;
>> +
>> +		if (j < pcr_selection.size_of_select) {
>> +			chip->allocated_banks[nr_alloc_banks] = hash_alg;
>> +			nr_alloc_banks++;
>> +		}
>> +
> 
> Why was this needed? Can CAP_PCRS return completely unallocated banks?

This was discussed for patch v4 1/6:
---

Nayna wrote:

# /usr/local/bin/tssgetcapability -cap 5
2 PCR selections
     hash TPM_ALG_SHA1
     TPMS_PCR_SELECTION length 3
     ff ff ff
     hash TPM_ALG_SHA256
     TPMS_PCR_SELECTION length 3
     00 00 00

The pcr_select fields - "ff ff ff" and "00 00 00" - are bit masks for
the enabled PCRs. The SHA1 bank is enabled for all PCRs (0-23), while
the SHA256 bank is not enabled.
---

> Kind of out-of-context for the rest of the changes.
> 
> Should this be a bug fix of its own because it looks like as this is a
> bug fix for existing code, and not a new feature? Just asking because
> I don't yet fully understand this change.

If we store in tpm_chip the possible banks, IMA would calculate more
digests unnecessarily. But this problem does not happen without my patch
set, because tpm_pcr_extend() only accepts a SHA1 digest.


> Anyway, I believe that you can streamline this by:
> 
> /* Check that at least some of the PCRs have been allocated. This is
>   * required because CAP_PCRS ...
>   */
> if (memchr_inv(pcr_selection.pcr_select, 0, pcr_selection.size_of_select))
> 	nr_allocated_banks++;
> 
> [yeah, comment would be awesome about CAP_PCRS. Did not finish up the
> comment because I don't know the answer]
> 
> In addition, it would be consistent to call the local variable also
> nr_allocated_banks (not nr_alloc_banks).

Unfortunately, I exceed the limit of characters per line.

Roberto


> /Jarkko
> 

-- 
HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063
Managing Director: Bo PENG, Jian LI, Yanli SHI

Re: [PATCH v6 5/7] tpm: retrieve digest size of unknown algorithms with PCR read

[Roberto Sassu]

On 12/5/2018 12:53 AM, Jarkko Sakkinen wrote:
> On Tue, Dec 04, 2018 at 09:21:36AM +0100, Roberto Sassu wrote:
>> +	for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) {
>> +		enum hash_algo crypto_algo = tpm2_hash_map[i].crypto_id;
>> +
>> +		if (bank->alg_id != tpm2_hash_map[i].tpm_id)
>> +			continue;
>> +
>> +		bank->digest_size = hash_digest_size[crypto_algo];
>> +		bank->crypto_id = crypto_algo;
>> +		return 0;
>> +	}
>> +
>> +	return tpm2_pcr_read(chip, 0, &digest, &bank->digest_size);
>> +}
> 
> This is a part that I don't get. Coud you just always call
> tpm2_pcr_read() instead of this complexity

First, we avoid operations that may increase the boot time. Second, the
loop is necessary to obtain the crypto subsystem identifier from a TPM
algorithm identifier.

Roberto


> /Jarkko
> 

-- 
HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063
Managing Director: Bo PENG, Jian LI, Yanli SHI

Re: [PATCH v6 6/7] tpm: ensure that the output of PCR read contains the correct digest size

[Roberto Sassu]

On 12/5/2018 1:46 AM, Jarkko Sakkinen wrote:
> On Tue, Dec 04, 2018 at 04:09:10PM -0800, Jarkko Sakkinen wrote:
>> On Tue, Dec 04, 2018 at 09:21:37AM +0100, Roberto Sassu wrote:
>>>   	out = (struct tpm2_pcr_read_out *)&buf.data[TPM_HEADER_SIZE];
>>>   	digest_size = be16_to_cpu(out->digest_size);
>>> -	if (digest_size > sizeof(digest->digest)) {
>>> +	if (digest_size > sizeof(digest->digest) ||
>>> +	    (!digest_size_ptr && digest_size != expected_digest_size)) {
>>>   		rc = -EINVAL;
>>>   		goto out;
>>>   	}
>>
>> Just noticed this but you must squash 4-6 because applying only
>> previous commits will result a broken tree. It will be much bigger
>> commit but won't be broken.
>>
>> I think you should also feed min_rsp_body_length as you should be
>> able to precalculate.
>>
>> Last time I was asking why this isn't a bug fix. It is even for
>> the existing code. The existing code should have a bug fix that
>> checks that the received digest size so that it is the expected
>> SHA1 size before we can apply this commit.
> 
> My bad. This is not the same deal as the code because in the old code we
> always copy a constant block. Here we use the variable as parameter for
> memcpy() so it is better to check the size. You can ignore the last
> paragraph completely. Sorry, had to double check this one.
> 
> There is no need to do any type of bug fix for the current tree.
> 
> Still 4-6 need to be squashed in order to not put purposely the tree
> into broken state.

Ok. I keep the description of 5, and add few details from 4 and 6.

Roberto


> /Jarko
> 

-- 
HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063
Managing Director: Bo PENG, Jian LI, Yanli SHI

Re: [PATCH v6 7/7] tpm: pass an array of tpm_bank_list structures to tpm_pcr_extend()

[Roberto Sassu]

On 12/5/2018 1:14 AM, Jarkko Sakkinen wrote:
> On Tue, Dec 04, 2018 at 09:21:38AM +0100, Roberto Sassu wrote:
>> The new tpm_bank_list structure has been preferred to the tpm_digest
>> structure, to let the caller specify the size of the digest (which may be
>> unknown to the TPM driver).
> 
> Why is that? Didn't previous commit query these?
> 
>> +struct tpm_bank_list {
>> +	u16 alg_id;
>> +	u16 extend_size;
>> +	const u8 *extend_array;
>> +};
> 
> Naming is not good here. If this only for extending shouldn't that
> be in the structs name?

tpm_extend_input?

Roberto


> /Jarkko
> 

-- 
HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063
Managing Director: Bo PENG, Jian LI, Yanli SHI

Re: [PATCH v6 7/7] tpm: pass an array of tpm_bank_list structures to tpm_pcr_extend()

[Roberto Sassu]

On 12/5/2018 1:14 AM, Jarkko Sakkinen wrote:
> On Tue, Dec 04, 2018 at 09:21:38AM +0100, Roberto Sassu wrote:
>> The new tpm_bank_list structure has been preferred to the tpm_digest
>> structure, to let the caller specify the size of the digest (which may be
>> unknown to the TPM driver).
> 
> Why is that? Didn't previous commit query these?

Since the TPM driver pads/truncates the first digest passed by the
caller to extend PCRs for which no digest was provided, it must know
which amount of data it can use. It is possible that the algorithm of
the first digest is unknown for the TPM driver, if the caller of
tpm_pcr_extend() didn't check chip->allocated_banks.

By requiring that the caller passes also the digest size, this problem
does not arise. It seems reasonable to me to pass this information, as
the caller calculated the digest and it should know the digest size.

Roberto


>> +struct tpm_bank_list {
>> +	u16 alg_id;
>> +	u16 extend_size;
>> +	const u8 *extend_array;
>> +};
> 
> Naming is not good here. If this only for extending shouldn't that
> be in the structs name?
> 
> /Jarkko
> 

-- 
HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063
Managing Director: Bo PENG, Jian LI, Yanli SHI

Re: [PATCH v6 4/7] tpm: modify tpm_pcr_read() definition to pass a TPM hash algorithm

[Mimi Zohar]

On Wed, 2018-12-05 at 15:31 -0500, Mimi Zohar wrote:
> On Tue, 2018-12-04 at 15:40 -0800, Jarkko Sakkinen wrote:
> > On Tue, Dec 04, 2018 at 09:21:35AM +0100, Roberto Sassu wrote:
> > > Currently the TPM driver allows other kernel subsystems to read only the
> > > SHA1 PCR bank. This patch modifies the parameters of tpm_pcr_read() and
> > > tpm2_pcr_read() to pass a tpm_digest structure, which contains the desired
> > > hash algorithm. Also, since commit 125a22105410 ("tpm: React correctly to
> > > RC_TESTING from TPM 2.0 self tests") removed the call to tpm2_pcr_read(),
> > > the new parameter is expected to be always not NULL.
> > > 
> > > Due to the API change, IMA functions have been modified.
> > > 
> > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> > > Acked-by: Mimi Zohar <zohar@linux.ibm.com>
> > 
> > Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> > 
> > Mimi, Nayna, can you help with testing this (because of the IMA change)?
> 
> It's up & running and the measurement list verifies against the TPM
> PCR.  Although this system has two algorithms enabled, all of the PCRs
> are allocated for one algorithm and none for the other.  I'm still
> looking around for another system with PCR 10 enabled for multiple
> algorithms.

PCRs for sha1 and sha256 algorithms are being updated and the
measurement list verifies against the SHA1 PCR-10.

Roberto, have you added support in ima-evm-utils to validate the other
banks?

Mimi

Re: [PATCH v6 4/7] tpm: modify tpm_pcr_read() definition to pass a TPM hash algorithm

[Roberto Sassu]

On 12/6/2018 8:49 PM, Mimi Zohar wrote:
> On Wed, 2018-12-05 at 15:31 -0500, Mimi Zohar wrote:
>> On Tue, 2018-12-04 at 15:40 -0800, Jarkko Sakkinen wrote:
>>> On Tue, Dec 04, 2018 at 09:21:35AM +0100, Roberto Sassu wrote:
>>>> Currently the TPM driver allows other kernel subsystems to read only the
>>>> SHA1 PCR bank. This patch modifies the parameters of tpm_pcr_read() and
>>>> tpm2_pcr_read() to pass a tpm_digest structure, which contains the desired
>>>> hash algorithm. Also, since commit 125a22105410 ("tpm: React correctly to
>>>> RC_TESTING from TPM 2.0 self tests") removed the call to tpm2_pcr_read(),
>>>> the new parameter is expected to be always not NULL.
>>>>
>>>> Due to the API change, IMA functions have been modified.
>>>>
>>>> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
>>>> Acked-by: Mimi Zohar <zohar@linux.ibm.com>
>>>
>>> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
>>>
>>> Mimi, Nayna, can you help with testing this (because of the IMA change)?
>>
>> It's up & running and the measurement list verifies against the TPM
>> PCR.  Although this system has two algorithms enabled, all of the PCRs
>> are allocated for one algorithm and none for the other.  I'm still
>> looking around for another system with PCR 10 enabled for multiple
>> algorithms.
> 
> PCRs for sha1 and sha256 algorithms are being updated and the
> measurement list verifies against the SHA1 PCR-10.
> 
> Roberto, have you added support in ima-evm-utils to validate the other
> banks?

I modified IMA LTP.

Roberto


> Mimi
> 

-- 
HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063
Managing Director: Bo PENG, Jian LI, Yanli SHI

Re: [PATCH v6 4/7] tpm: modify tpm_pcr_read() definition to pass a TPM hash algorithm

[Nayna Jain]

On 12/05/2018 05:10 AM, Jarkko Sakkinen wrote:
> On Tue, Dec 04, 2018 at 09:21:35AM +0100, Roberto Sassu wrote:
>> Currently the TPM driver allows other kernel subsystems to read only the
>> SHA1 PCR bank. This patch modifies the parameters of tpm_pcr_read() and
>> tpm2_pcr_read() to pass a tpm_digest structure, which contains the desired
>> hash algorithm. Also, since commit 125a22105410 ("tpm: React correctly to
>> RC_TESTING from TPM 2.0 self tests") removed the call to tpm2_pcr_read(),
>> the new parameter is expected to be always not NULL.
>>
>> Due to the API change, IMA functions have been modified.
>>
>> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
>> Acked-by: Mimi Zohar <zohar@linux.ibm.com>
> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
>
> Mimi, Nayna, can you help with testing this (because of the IMA change)?


Tested-by: Nayna Jain <nayna@linux.ibm.com>

Thanks & Regards,
     - Nayna



>
> /Jarkko
>

Re: [PATCH v6 2/7] tpm: add _head suffix to tcg_efi_specid_event and tcg_pcr_event2

[Nayna Jain]

On 12/04/2018 01:51 PM, Roberto Sassu wrote:
> TCG defines two structures, TCG_EfiSpecIDEventStruct and TCG_PCR_EVENT2,
> which contain variable-sized arrays in the middle of the definition.
>
> Since these structures are not suitable for type casting, this patch
> removes structure members after the variable-sized arrays and adds the
> _head suffix to the structure name, to indicate that the renamed structures
> do not contain all fields defined by TCG.
>
> Lastly, given that variable-sized arrays are now in the last position, and
> given that the size of the arrays cannot be determined in advance, this
> patch also sets the size of those arrays to zero and removes the definition
> of TPM2_ACTIVE_PCR_BANKS.
>
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>


Tested-by: Nayna Jain <nayna@linux.ibm.com>

Thanks & Regards,
     - Nayna

Re: [PATCH v6 4/7] tpm: modify tpm_pcr_read() definition to pass a TPM hash algorithm

[Mimi Zohar]

On Fri, 2018-12-07 at 15:51 +0100, Roberto Sassu wrote:
> On 12/6/2018 8:49 PM, Mimi Zohar wrote:

> > PCRs for sha1 and sha256 algorithms are being updated and the
> > measurement list verifies against the SHA1 PCR-10.
> > 
> > Roberto, have you added support in ima-evm-utils to validate the other
> > banks?
> 
> I modified IMA LTP.

I'm not finding it.  Was the test for the current code, where the same
value is being padded for different algorithms, or for walking the
proposed hash agile format?

Mimi

Re: [PATCH v6 4/7] tpm: modify tpm_pcr_read() definition to pass a TPM hash algorithm

[Roberto Sassu]

On 12/9/2018 9:32 PM, Mimi Zohar wrote:
> On Fri, 2018-12-07 at 15:51 +0100, Roberto Sassu wrote:
>> On 12/6/2018 8:49 PM, Mimi Zohar wrote:
> 
>>> PCRs for sha1 and sha256 algorithms are being updated and the
>>> measurement list verifies against the SHA1 PCR-10.
>>>
>>> Roberto, have you added support in ima-evm-utils to validate the other
>>> banks?
>>
>> I modified IMA LTP.
> 
> I'm not finding it.  Was the test for the current code, where the same
> value is being padded for different algorithms, or for walking the
> proposed hash agile format?

I did not send the patch yet.

Roberto


> Mimi
> 

-- 
HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063
Managing Director: Bo PENG, Jian LI, Yanli SHI

Re: [PATCH v6 5/7] tpm: retrieve digest size of unknown algorithms with PCR read

[Jarkko Sakkinen]

On Thu, Dec 06, 2018 at 07:00:13PM +0100, Roberto Sassu wrote:
> On 12/5/2018 12:53 AM, Jarkko Sakkinen wrote:
> > On Tue, Dec 04, 2018 at 09:21:36AM +0100, Roberto Sassu wrote:
> > > +	for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) {
> > > +		enum hash_algo crypto_algo = tpm2_hash_map[i].crypto_id;
> > > +
> > > +		if (bank->alg_id != tpm2_hash_map[i].tpm_id)
> > > +			continue;
> > > +
> > > +		bank->digest_size = hash_digest_size[crypto_algo];
> > > +		bank->crypto_id = crypto_algo;
> > > +		return 0;
> > > +	}
> > > +
> > > +	return tpm2_pcr_read(chip, 0, &digest, &bank->digest_size);
> > > +}
> > 
> > This is a part that I don't get. Coud you just always call
> > tpm2_pcr_read() instead of this complexity
> 
> First, we avoid operations that may increase the boot time. Second, the
> loop is necessary to obtain the crypto subsystem identifier from a TPM
> algorithm identifier.

I think here would be a comment in place and it would be fine.

/Jarkko

Re: [PATCH v6 6/7] tpm: ensure that the output of PCR read contains the correct digest size

[Jarkko Sakkinen]

On Thu, Dec 06, 2018 at 07:07:34PM +0100, Roberto Sassu wrote:
> > Still 4-6 need to be squashed in order to not put purposely the tree
> > into broken state.
> 
> Ok. I keep the description of 5, and add few details from 4 and 6.

Yeah, keeping patches small is one thing, but the commits should not
be crippled. Therefore, I rather have these squashed.

/Jarkko

Re: [PATCH v6 7/7] tpm: pass an array of tpm_bank_list structures to tpm_pcr_extend()

[Jarkko Sakkinen]

On Thu, Dec 06, 2018 at 07:09:48PM +0100, Roberto Sassu wrote:
> 
> 
> On 12/5/2018 1:14 AM, Jarkko Sakkinen wrote:
> > On Tue, Dec 04, 2018 at 09:21:38AM +0100, Roberto Sassu wrote:
> > > The new tpm_bank_list structure has been preferred to the tpm_digest
> > > structure, to let the caller specify the size of the digest (which may be
> > > unknown to the TPM driver).
> > 
> > Why is that? Didn't previous commit query these?
> > 
> > > +struct tpm_bank_list {
> > > +	u16 alg_id;
> > > +	u16 extend_size;
> > > +	const u8 *extend_array;
> > > +};
> > 
> > Naming is not good here. If this only for extending shouldn't that
> > be in the structs name?
> 
> tpm_extend_input?

I think something like this would be appropriate:

struct tpm_extend_digest {
	u16 alg_id;
	u16 size;
	u8 *data;
};

/Jarkko

Re: [PATCH v6 7/7] tpm: pass an array of tpm_bank_list structures to tpm_pcr_extend()

[Jarkko Sakkinen]

On Thu, Dec 06, 2018 at 07:38:30PM +0100, Roberto Sassu wrote:
> On 12/5/2018 1:14 AM, Jarkko Sakkinen wrote:
> > On Tue, Dec 04, 2018 at 09:21:38AM +0100, Roberto Sassu wrote:
> > > The new tpm_bank_list structure has been preferred to the tpm_digest
> > > structure, to let the caller specify the size of the digest (which may be
> > > unknown to the TPM driver).
> > 
> > Why is that? Didn't previous commit query these?
> 
> Since the TPM driver pads/truncates the first digest passed by the
> caller to extend PCRs for which no digest was provided, it must know
> which amount of data it can use. It is possible that the algorithm of
> the first digest is unknown for the TPM driver, if the caller of
> tpm_pcr_extend() didn't check chip->allocated_banks.
> 
> By requiring that the caller passes also the digest size, this problem
> does not arise. It seems reasonable to me to pass this information, as
> the caller calculated the digest and it should know the digest size.

OK. I noticed something other things that look to alarming:

1. The function does not fail if alg_id is not found. This will go
   silent.
2. The function does not fail if there is a mismatch with the digest
   sizes.

/Jarkko

Re: [PATCH v6 4/7] tpm: modify tpm_pcr_read() definition to pass a TPM hash algorithm

[Jarkko Sakkinen]

On Thu, Dec 06, 2018 at 01:44:58PM +0530, Nayna Jain wrote:
> 
> On 12/05/2018 05:10 AM, Jarkko Sakkinen wrote:
> > On Tue, Dec 04, 2018 at 09:21:35AM +0100, Roberto Sassu wrote:
> > > Currently the TPM driver allows other kernel subsystems to read only the
> > > SHA1 PCR bank. This patch modifies the parameters of tpm_pcr_read() and
> > > tpm2_pcr_read() to pass a tpm_digest structure, which contains the desired
> > > hash algorithm. Also, since commit 125a22105410 ("tpm: React correctly to
> > > RC_TESTING from TPM 2.0 self tests") removed the call to tpm2_pcr_read(),
> > > the new parameter is expected to be always not NULL.
> > > 
> > > Due to the API change, IMA functions have been modified.
> > > 
> > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> > > Acked-by: Mimi Zohar <zohar@linux.ibm.com>
> > Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> > 
> > Mimi, Nayna, can you help with testing this (because of the IMA change)?
> 
> Sure, I will try to do by end of my day tomorrow,

Awesome, thank you.

/Jarkko

Re: [PATCH v6 1/7] tpm: dynamically allocate the allocated_banks array

[Jarkko Sakkinen]

On Thu, Dec 06, 2018 at 06:56:33PM +0100, Roberto Sassu wrote:
> 2 PCR selections
>     hash TPM_ALG_SHA1
>     TPMS_PCR_SELECTION length 3
>     ff ff ff
>     hash TPM_ALG_SHA256
>     TPMS_PCR_SELECTION length 3
>     00 00 00
> 
> The pcr_select fields - "ff ff ff" and "00 00 00" - are bit masks for
> the enabled PCRs. The SHA1 bank is enabled for all PCRs (0-23), while
> the SHA256 bank is not enabled.

Uh, thanks. Can you add a note to the commit message?

 
> > 
> > /* Check that at least some of the PCRs have been allocated. This is
> >   * required because CAP_PCRS ...
> >   */
> > if (memchr_inv(pcr_selection.pcr_select, 0, pcr_selection.size_of_select))
> > 	nr_allocated_banks++;
> > 
> > [yeah, comment would be awesome about CAP_PCRS. Did not finish up the
> > comment because I don't know the answer]
> > 
> > In addition, it would be consistent to call the local variable also
> > nr_allocated_banks (not nr_alloc_banks).
> 
> Unfortunately, I exceed the limit of characters per line.

Not sure what you mean?

/Jarkko

Re: [PATCH v6 7/7] tpm: pass an array of tpm_bank_list structures to tpm_pcr_extend()

[Roberto Sassu]

On 12/12/2018 7:27 PM, Jarkko Sakkinen wrote:
> On Thu, Dec 06, 2018 at 07:38:30PM +0100, Roberto Sassu wrote:
>> On 12/5/2018 1:14 AM, Jarkko Sakkinen wrote:
>>> On Tue, Dec 04, 2018 at 09:21:38AM +0100, Roberto Sassu wrote:
>>>> The new tpm_bank_list structure has been preferred to the tpm_digest
>>>> structure, to let the caller specify the size of the digest (which may be
>>>> unknown to the TPM driver).
>>>
>>> Why is that? Didn't previous commit query these?
>>
>> Since the TPM driver pads/truncates the first digest passed by the
>> caller to extend PCRs for which no digest was provided, it must know
>> which amount of data it can use. It is possible that the algorithm of
>> the first digest is unknown for the TPM driver, if the caller of
>> tpm_pcr_extend() didn't check chip->allocated_banks.
>>
>> By requiring that the caller passes also the digest size, this problem
>> does not arise. It seems reasonable to me to pass this information, as
>> the caller calculated the digest and it should know the digest size.
> 
> OK. I noticed something other things that look to alarming:
> 
> 1. The function does not fail if alg_id is not found. This will go
>     silent.

It is intentional. If alg_id is not found, the PCR is extended with the
first digest passed by the caller of tpm_pcr_extend(). If no digest was
provided, the PCR is extended with 0s. This is done to prevent that
PCRs in unused banks are extended later with fake measurements.


> 2. The function does not fail if there is a mismatch with the digest
>     sizes.

The data passed by the caller of tpm_pcr_extend() is copied to
dummy_hash, which has the maximum length. Then, tpm2_pcr_extend() takes
from dummy_hash as many bytes as needed, depending on the current
algorithm.

Roberto


> /Jarkko
> 

-- 
HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063
Managing Director: Bo PENG, Jian LI, Yanli SHI

Re: [PATCH v6 1/7] tpm: dynamically allocate the allocated_banks array

[Roberto Sassu]

On 12/12/2018 7:32 PM, Jarkko Sakkinen wrote:
> On Thu, Dec 06, 2018 at 06:56:33PM +0100, Roberto Sassu wrote:
>> 2 PCR selections
>>      hash TPM_ALG_SHA1
>>      TPMS_PCR_SELECTION length 3
>>      ff ff ff
>>      hash TPM_ALG_SHA256
>>      TPMS_PCR_SELECTION length 3
>>      00 00 00
>>
>> The pcr_select fields - "ff ff ff" and "00 00 00" - are bit masks for
>> the enabled PCRs. The SHA1 bank is enabled for all PCRs (0-23), while
>> the SHA256 bank is not enabled.
> 
> Uh, thanks. Can you add a note to the commit message?

Ok.


>>>
>>> /* Check that at least some of the PCRs have been allocated. This is
>>>    * required because CAP_PCRS ...
>>>    */
>>> if (memchr_inv(pcr_selection.pcr_select, 0, pcr_selection.size_of_select))
>>> 	nr_allocated_banks++;
>>>
>>> [yeah, comment would be awesome about CAP_PCRS. Did not finish up the
>>> comment because I don't know the answer]
>>>
>>> In addition, it would be consistent to call the local variable also
>>> nr_allocated_banks (not nr_alloc_banks).
>>
>> Unfortunately, I exceed the limit of characters per line.
> 
> Not sure what you mean?

---
-		chip->allocated_banks[nr_alloc_banks] = hash_alg;
+		chip->allocated_banks[nr_alloc_banks].alg_id = hash_alg;
---

If I use nr_allocated_banks, the line above (see patch 5/7) exceeds the
limit of 80 characters.

Roberto


> /Jarkko
> 

-- 
HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063
Managing Director: Bo PENG, Jian LI, Yanli SHI

Re: [PATCH v6 7/7] tpm: pass an array of tpm_bank_list structures to tpm_pcr_extend()

[Jarkko Sakkinen]

On Thu, Dec 13, 2018 at 08:57:17AM +0100, Roberto Sassu wrote:
> > 1. The function does not fail if alg_id is not found. This will go
> >     silent.
> 
> It is intentional. If alg_id is not found, the PCR is extended with the
> first digest passed by the caller of tpm_pcr_extend(). If no digest was
> provided, the PCR is extended with 0s. This is done to prevent that
> PCRs in unused banks are extended later with fake measurements.
> 
> 
> > 2. The function does not fail if there is a mismatch with the digest
> >     sizes.
> 
> The data passed by the caller of tpm_pcr_extend() is copied to
> dummy_hash, which has the maximum length. Then, tpm2_pcr_extend() takes
> from dummy_hash as many bytes as needed, depending on the current
> algorithm.

I would suggest to document these corner cases to the function long
description to make it easy and obvious to understand.

/Jarkko