diff mbox series

[v8,1/7] tpm: dynamically allocate the allocated_banks array

Message ID 20190124154910.29948-2-roberto.sassu@huawei.com (mailing list archive)
State New, archived
Headers show
Series tpm: retrieve digest size of unknown algorithms from TPM | expand

Commit Message

Roberto Sassu Jan. 24, 2019, 3:49 p.m. UTC 
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(). If a bank is not allocated, the TPM returns that
bank in TPML_PCR_SELECTION, with all bits in the mask set to zero. In this
case, the bank is not included in chip->allocated_banks, to avoid that TPM
driver users unnecessarily calculate a digest for that bank.

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      | 31 +++++++++++++++++++++----------
 5 files changed, 44 insertions(+), 19 deletions(-)

Comments

Jarkko Sakkinen Jan. 29, 2019, 7:29 p.m. UTC | #1 
On Thu, Jan 24, 2019 at 04:49:04PM +0100, Roberto Sassu wrote:
> +	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;

Everything else looks nice in this patch except this.

You always branch for TPM 1.2, and it will always have just SHA1. This
is unnecessary.

/Jarkko
Roberto Sassu Jan. 30, 2019, 7:52 a.m. UTC | #2 
On 1/29/2019 8:29 PM, Jarkko Sakkinen wrote:
> On Thu, Jan 24, 2019 at 04:49:04PM +0100, Roberto Sassu wrote:
>> +	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;
> 
> Everything else looks nice in this patch except this.
> 
> You always branch for TPM 1.2, and it will always have just SHA1. This
> is unnecessary.

Without this, users of the TPM driver have to call tpm_is_tpm2() first,
while instead they can look directly at chip->allocated_banks.

Roberto


> /Jarkko
>
Jarkko Sakkinen Jan. 30, 2019, 12:01 p.m. UTC | #3 
On Wed, Jan 30, 2019 at 08:52:40AM +0100, Roberto Sassu wrote:
> On 1/29/2019 8:29 PM, Jarkko Sakkinen wrote:
> > On Thu, Jan 24, 2019 at 04:49:04PM +0100, Roberto Sassu wrote:
> > > +	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;
> > 
> > Everything else looks nice in this patch except this.
> > 
> > You always branch for TPM 1.2, and it will always have just SHA1. This
> > is unnecessary.
> 
> Without this, users of the TPM driver have to call tpm_is_tpm2() first,
> while instead they can look directly at chip->allocated_banks.

I realized this after going through the whole patch set and sleeping
one night :-) You can keep it. I was mistaken here.

/Jarkko
diff mbox series

Patch

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..158c34721c8a 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);
@@ -825,8 +825,10 @@  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;
@@ -844,11 +846,14 @@  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 +862,7 @@  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 +871,23 @@  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);
+
+		pcr_select_offset = memchr_inv(pcr_selection.pcr_select, 0,
+					       pcr_selection.size_of_select);
+		if (pcr_select_offset) {
+			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;