On Fri, Dec 21, 2018 at 10:40:09AM +0100, Roberto Sassu wrote:

On 12/20/2018 3:55 PM, Jarkko Sakkinen wrote:

quoted

On Thu, Dec 13, 2018 at 11:29:41AM +0100, Roberto Sassu wrote:

quoted

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 <redacted>
---
  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;

You could preallocate digest list and place it to struct tpm_chip
instead of doing it everytime tpm_pcr_extend() called.

This part will be removed with patch 5/5.

Even if it did, it does not make this patch unbroken.

/Jarkko