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Re: [PATCH v5 14/17] tpm: remove TPM_TRANSMIT_UNLOCKED flag




On 11/8/18 9:15 AM, Jarkko Sakkinen wrote:
Added locking as part of tpm_try_get_ops() and tpm_put_ops() as they are
anyway used in most of the call sites except in tpmrm_release() where we
take the locks manually.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
---
  drivers/char/tpm/tpm-chip.c       |  2 ++
  drivers/char/tpm/tpm-dev-common.c |  4 +---
  drivers/char/tpm/tpm-interface.c  |  8 --------
  drivers/char/tpm/tpm.h            |  8 ++------
  drivers/char/tpm/tpm2-cmd.c       | 13 ++++---------
  drivers/char/tpm/tpm2-space.c     | 15 ++++++---------
  6 files changed, 15 insertions(+), 35 deletions(-)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 32db84683c40..157505b0f755 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -58,6 +58,7 @@ int tpm_try_get_ops(struct tpm_chip *chip)
  	if (!chip->ops)
  		goto out_lock;

+	mutex_lock(&chip->tpm_mutex);
  	return 0;
  out_lock:
  	up_read(&chip->ops_sem);
@@ -75,6 +76,7 @@ EXPORT_SYMBOL_GPL(tpm_try_get_ops);
   */
  void tpm_put_ops(struct tpm_chip *chip)
  {
+	mutex_unlock(&chip->tpm_mutex);
  	up_read(&chip->ops_sem);
  	put_device(&chip->dev);
  }
diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c
index c7dc54930576..582caefcf19b 100644
--- a/drivers/char/tpm/tpm-dev-common.c
+++ b/drivers/char/tpm/tpm-dev-common.c
@@ -33,7 +33,6 @@ static ssize_t tpm_dev_transmit(struct tpm_chip *chip, struct tpm_space *space,
  	struct tpm_header *header = (void *)buf;
  	ssize_t ret, len;

-	mutex_lock(&chip->tpm_mutex);
  	ret = tpm2_prepare_space(chip, space, buf, bufsiz);
  	/* If the command is not implemented by the TPM, synthesize a
  	 * response with a TPM2_RC_COMMAND_CODE return for user-space.
@@ -48,7 +47,7 @@ static ssize_t tpm_dev_transmit(struct tpm_chip *chip, struct tpm_space *space,
  	if (ret)
  		goto out_lock;

-	len = tpm_transmit(chip, buf, bufsiz, TPM_TRANSMIT_UNLOCKED);
+	len = tpm_transmit(chip, buf, bufsiz, 0);
  	if (len < 0)
  		ret = len;

@@ -57,7 +56,6 @@ static ssize_t tpm_dev_transmit(struct tpm_chip *chip, struct tpm_space *space,
  	else
  		ret = tpm2_commit_space(chip, space, buf, &len);
  out_lock:
-	mutex_unlock(&chip->tpm_mutex);
  	return ret ? ret : len;
  }

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 8d75c103f280..5865b9671d20 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -227,10 +227,6 @@ ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
  	memcpy(save, buf, save_size);

  	for (;;) {
-		if (!(flags & TPM_TRANSMIT_UNLOCKED) &&
-		    !(flags & TPM_TRANSMIT_NESTED))
-			mutex_lock(&chip->tpm_mutex);
-
  		if (chip->ops->clk_enable != NULL)
  			chip->ops->clk_enable(chip, true);

@@ -257,10 +253,6 @@ ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
  		if (chip->ops->clk_enable != NULL)
  			chip->ops->clk_enable(chip, false);

-		if (!(flags & TPM_TRANSMIT_UNLOCKED) &&
-		    !(flags & TPM_TRANSMIT_NESTED))
-			mutex_unlock(&chip->tpm_mutex);
-
  		if (ret < 0)
  			break;
  		rc = be32_to_cpu(header->return_code);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 10a5bcf806aa..c7c06de651a0 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -488,14 +488,10 @@ extern struct idr dev_nums_idr;
  /**
   * enum tpm_transmit_flags - flags for tpm_transmit()
   *
- * @TPM_TRANSMIT_UNLOCKED:	do not lock the chip
- * @TPM_TRANSMIT_NESTED:	discard setup steps (power management,
- *				locality) including locking (i.e. implicit
- *				UNLOCKED)
+ * %TPM_TRANSMIT_NESTED:	discard setup steps (power management, locality)
   */
  enum tpm_transmit_flags {
-	TPM_TRANSMIT_UNLOCKED	= BIT(0),
-	TPM_TRANSMIT_NESTED      = BIT(1),
+	TPM_TRANSMIT_NESTED      = BIT(0),
  };

  ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index f2b0e5c52a57..d6abc964ef66 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -652,17 +652,12 @@ int tpm2_unseal_trusted(struct tpm_chip *chip,
  	u32 blob_handle;
  	int rc;

-	mutex_lock(&chip->tpm_mutex);
-	rc = tpm2_load_cmd(chip, payload, options, &blob_handle,
-			   TPM_TRANSMIT_UNLOCKED);
+	rc = tpm2_load_cmd(chip, payload, options, &blob_handle, 0);
  	if (rc)
-		goto out;
+		return rc;

-	rc = tpm2_unseal_cmd(chip, payload, options, blob_handle,
-			     TPM_TRANSMIT_UNLOCKED);
-	tpm2_flush_context_cmd(chip, blob_handle, TPM_TRANSMIT_UNLOCKED);
-out:
-	mutex_unlock(&chip->tpm_mutex);
+	rc = tpm2_unseal_cmd(chip, payload, options, blob_handle, 0);
+	tpm2_flush_context_cmd(chip, blob_handle, 0);


This lock was covering quite a few commands from being interfered by others. Is this still guaranteed to work after or can different subsystems like trusted keys and IMA and /dev/tpm0 users interfere with this previous atomic sequence ?


  	return rc;
  }

diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
index d1c371db1ab7..341d4b90ba2f 100644
--- a/drivers/char/tpm/tpm2-space.c
+++ b/drivers/char/tpm/tpm2-space.c
@@ -38,8 +38,7 @@ static void tpm2_flush_sessions(struct tpm_chip *chip, struct tpm_space *space)

  	for (i = 0; i < ARRAY_SIZE(space->session_tbl); i++) {
  		if (space->session_tbl[i])
-			tpm2_flush_context_cmd(chip, space->session_tbl[i],
-					       TPM_TRANSMIT_UNLOCKED);
+			tpm2_flush_context_cmd(chip, space->session_tbl[i], 0);
  	}
  }

@@ -83,7 +82,7 @@ static int tpm2_load_context(struct tpm_chip *chip, u8 *buf,
  	body_size = sizeof(*ctx) + be16_to_cpu(ctx->blob_size);
  	tpm_buf_append(&tbuf, &buf[*offset], body_size);

-	rc = tpm_transmit_cmd(chip, &tbuf, 4, TPM_TRANSMIT_UNLOCKED, NULL);
+	rc = tpm_transmit_cmd(chip, &tbuf, 4, 0, NULL);
  	if (rc < 0) {
  		dev_warn(&chip->dev, "%s: failed with a system error %d\n",
  			 __func__, rc);
@@ -131,7 +130,7 @@ static int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf,

  	tpm_buf_append_u32(&tbuf, handle);

-	rc = tpm_transmit_cmd(chip, &tbuf, 0, TPM_TRANSMIT_UNLOCKED, NULL);
+	rc = tpm_transmit_cmd(chip, &tbuf, 0, 0, NULL);
  	if (rc < 0) {
  		dev_warn(&chip->dev, "%s: failed with a system error %d\n",
  			 __func__, rc);
@@ -167,8 +166,7 @@ void tpm2_flush_space(struct tpm_chip *chip)

  	for (i = 0; i < ARRAY_SIZE(space->context_tbl); i++)
  		if (space->context_tbl[i] && ~space->context_tbl[i])
-			tpm2_flush_context_cmd(chip, space->context_tbl[i],
-					       TPM_TRANSMIT_UNLOCKED);
+			tpm2_flush_context_cmd(chip, space->context_tbl[i], 0);

  	tpm2_flush_sessions(chip, space);
  }
@@ -417,7 +415,7 @@ static int tpm2_map_response_header(struct tpm_chip *chip, u32 cc, u8 *rsp,

  	return 0;
  out_no_slots:
-	tpm2_flush_context_cmd(chip, phandle, TPM_TRANSMIT_UNLOCKED);
+	tpm2_flush_context_cmd(chip, phandle, 0);
  	dev_warn(&chip->dev, "%s: out of slots for 0x%08X\n", __func__,
  		 phandle);
  	return -ENOMEM;
@@ -504,8 +502,7 @@ static int tpm2_save_space(struct tpm_chip *chip)
  		} else if (rc)
  			return rc;

-		tpm2_flush_context_cmd(chip, space->context_tbl[i],
-				       TPM_TRANSMIT_UNLOCKED);
+		tpm2_flush_context_cmd(chip, space->context_tbl[i], 0);
  		space->context_tbl[i] = ~0;
  	}