diff mbox series

[v3,04/16] tpm: call tpm2_flush_space() on error in tpm_try_transmit()

Message ID 20181105014552.20262-5-jarkko.sakkinen@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series Remove nested TPM operations | expand

Commit Message

Jarkko Sakkinen Nov. 5, 2018, 1:45 a.m. UTC
Always call tpm2_flush_space() on failure in tpm_try_transmit() so that
the volatile memory of the TPM gets cleared. If /dev/tpm0 does not have
sufficient permissions (usually it has), this could leak to the leakage
of TPM objects. Through /dev/tpmrm0 this issue does not raise new
security concerns.

Cc: stable@vger.kernel.org
Fixes: 745b361e989a ("tpm:tpm: infrastructure for TPM spaces")
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 drivers/char/tpm/tpm-interface.c | 28 +++++++++++++++++-----------
 drivers/char/tpm/tpm.h           |  1 +
 drivers/char/tpm/tpm2-space.c    |  2 +-
 3 files changed, 19 insertions(+), 12 deletions(-)

Comments

Stefan Berger Nov. 5, 2018, 10:01 p.m. UTC | #1
On 11/4/18 8:45 PM, Jarkko Sakkinen wrote:
> Always call tpm2_flush_space() on failure in tpm_try_transmit() so that
> the volatile memory of the TPM gets cleared. If /dev/tpm0 does not have
> sufficient permissions (usually it has), this could leak to the leakage

leak ->lead


> of TPM objects. Through /dev/tpmrm0 this issue does not raise new
> security concerns.
>
> Cc: stable@vger.kernel.org
> Fixes: 745b361e989a ("tpm:tpm: infrastructure for TPM spaces")
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> ---
>   drivers/char/tpm/tpm-interface.c | 28 +++++++++++++++++-----------
>   drivers/char/tpm/tpm.h           |  1 +
>   drivers/char/tpm/tpm2-space.c    |  2 +-
>   3 files changed, 19 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 64510ed81b46..ecda6f96cde0 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -224,14 +224,14 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
>
>   	rc = tpm2_prepare_space(chip, space, ordinal, buf);
>   	if (rc)
> -		goto out;
> +		goto out_idle;
>
>   	rc = chip->ops->send(chip, buf, count);
>   	if (rc < 0) {
>   		if (rc != -EPIPE)
>   			dev_err(&chip->dev,
>   				"%s: tpm_send: error %d\n", __func__, rc);
> -		goto out;
> +		goto out_space;
>   	}
>
>   	if (chip->flags & TPM_CHIP_FLAG_IRQ)
> @@ -247,7 +247,7 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
>   		if (chip->ops->req_canceled(chip, status)) {
>   			dev_err(&chip->dev, "Operation Canceled\n");
>   			rc = -ECANCELED;
> -			goto out;
> +			goto out_space;
>   		}
>
>   		tpm_msleep(TPM_TIMEOUT_POLL);
> @@ -257,7 +257,7 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
>   	chip->ops->cancel(chip);
>   	dev_err(&chip->dev, "Operation Timed out\n");
>   	rc = -ETIME;
> -	goto out;
> +	goto out_space;
>
>   out_recv:
>   	len = chip->ops->recv(chip, buf, bufsiz);
> @@ -265,22 +265,28 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
>   		rc = len;
>   		dev_err(&chip->dev,
>   			"tpm_transmit: tpm_recv: error %d\n", rc);
> -		goto out;
> +		goto out_idle;

Why not jump to out_space here and in 2 instances below?


>   	} else if (len < TPM_HEADER_SIZE) {
>   		rc = -EFAULT;
> -		goto out;
> +		goto out_idle;
>   	}
>
>   	if (len != be32_to_cpu(header->length)) {
>   		rc = -EFAULT;
> -		goto out;
> +		goto out_idle;
>   	}
>
> -	rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
> -	if (rc)
> -		dev_err(&chip->dev, "tpm2_commit_space: error %d\n", rc);
> +out_space:
> +	if (rc) {
> +		tpm2_flush_space(chip);
> +	} else {
> +		rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
> +		if (rc)
> +			dev_err(&chip->dev, "tpm2_commit_space: error %d\n",
> +				rc);
> +	}
>
> -out:
> +out_idle:
>   	/* may fail but do not override previous error value in rc */
>   	tpm_go_idle(chip, flags);
>
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index 49bca4d1e786..229ac42b644e 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -579,6 +579,7 @@ int tpm2_probe(struct tpm_chip *chip);
>   int tpm2_find_cc(struct tpm_chip *chip, u32 cc);
>   int tpm2_init_space(struct tpm_space *space);
>   void tpm2_del_space(struct tpm_chip *chip, struct tpm_space *space);
> +void tpm2_flush_space(struct tpm_chip *chip);
>   int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc,
>   		       u8 *cmd);
>   int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
> diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
> index 1131a8e7b79b..d53c882268ff 100644
> --- a/drivers/char/tpm/tpm2-space.c
> +++ b/drivers/char/tpm/tpm2-space.c
> @@ -162,7 +162,7 @@ static int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf,
>   	return 0;
>   }
>
> -static void tpm2_flush_space(struct tpm_chip *chip)
> +void tpm2_flush_space(struct tpm_chip *chip)
>   {
>   	struct tpm_space *space = &chip->work_space;
>   	int i;
Jarkko Sakkinen Nov. 6, 2018, 5:55 a.m. UTC | #2
On Mon, Nov 05, 2018 at 05:01:46PM -0500, Stefan Berger wrote:
> On 11/4/18 8:45 PM, Jarkko Sakkinen wrote:
> > Always call tpm2_flush_space() on failure in tpm_try_transmit() so that
> > the volatile memory of the TPM gets cleared. If /dev/tpm0 does not have
> > sufficient permissions (usually it has), this could leak to the leakage
> 
> leak ->lead
> 
> 
> > of TPM objects. Through /dev/tpmrm0 this issue does not raise new
> > security concerns.
> > 
> > Cc: stable@vger.kernel.org
> > Fixes: 745b361e989a ("tpm:tpm: infrastructure for TPM spaces")
> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> > ---
> >   drivers/char/tpm/tpm-interface.c | 28 +++++++++++++++++-----------
> >   drivers/char/tpm/tpm.h           |  1 +
> >   drivers/char/tpm/tpm2-space.c    |  2 +-
> >   3 files changed, 19 insertions(+), 12 deletions(-)
> > 
> > diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> > index 64510ed81b46..ecda6f96cde0 100644
> > --- a/drivers/char/tpm/tpm-interface.c
> > +++ b/drivers/char/tpm/tpm-interface.c
> > @@ -224,14 +224,14 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
> > 
> >   	rc = tpm2_prepare_space(chip, space, ordinal, buf);
> >   	if (rc)
> > -		goto out;
> > +		goto out_idle;
> > 
> >   	rc = chip->ops->send(chip, buf, count);
> >   	if (rc < 0) {
> >   		if (rc != -EPIPE)
> >   			dev_err(&chip->dev,
> >   				"%s: tpm_send: error %d\n", __func__, rc);
> > -		goto out;
> > +		goto out_space;
> >   	}
> > 
> >   	if (chip->flags & TPM_CHIP_FLAG_IRQ)
> > @@ -247,7 +247,7 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
> >   		if (chip->ops->req_canceled(chip, status)) {
> >   			dev_err(&chip->dev, "Operation Canceled\n");
> >   			rc = -ECANCELED;
> > -			goto out;
> > +			goto out_space;
> >   		}
> > 
> >   		tpm_msleep(TPM_TIMEOUT_POLL);
> > @@ -257,7 +257,7 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
> >   	chip->ops->cancel(chip);
> >   	dev_err(&chip->dev, "Operation Timed out\n");
> >   	rc = -ETIME;
> > -	goto out;
> > +	goto out_space;
> > 
> >   out_recv:
> >   	len = chip->ops->recv(chip, buf, bufsiz);
> > @@ -265,22 +265,28 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
> >   		rc = len;
> >   		dev_err(&chip->dev,
> >   			"tpm_transmit: tpm_recv: error %d\n", rc);
> > -		goto out;
> > +		goto out_idle;
> 
> Why not jump to out_space here and in 2 instances below?

Ugh, should (and meant) to be like that. Thanks!

/Jarkko
diff mbox series

Patch

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 64510ed81b46..ecda6f96cde0 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -224,14 +224,14 @@  static ssize_t tpm_try_transmit(struct tpm_chip *chip,
 
 	rc = tpm2_prepare_space(chip, space, ordinal, buf);
 	if (rc)
-		goto out;
+		goto out_idle;
 
 	rc = chip->ops->send(chip, buf, count);
 	if (rc < 0) {
 		if (rc != -EPIPE)
 			dev_err(&chip->dev,
 				"%s: tpm_send: error %d\n", __func__, rc);
-		goto out;
+		goto out_space;
 	}
 
 	if (chip->flags & TPM_CHIP_FLAG_IRQ)
@@ -247,7 +247,7 @@  static ssize_t tpm_try_transmit(struct tpm_chip *chip,
 		if (chip->ops->req_canceled(chip, status)) {
 			dev_err(&chip->dev, "Operation Canceled\n");
 			rc = -ECANCELED;
-			goto out;
+			goto out_space;
 		}
 
 		tpm_msleep(TPM_TIMEOUT_POLL);
@@ -257,7 +257,7 @@  static ssize_t tpm_try_transmit(struct tpm_chip *chip,
 	chip->ops->cancel(chip);
 	dev_err(&chip->dev, "Operation Timed out\n");
 	rc = -ETIME;
-	goto out;
+	goto out_space;
 
 out_recv:
 	len = chip->ops->recv(chip, buf, bufsiz);
@@ -265,22 +265,28 @@  static ssize_t tpm_try_transmit(struct tpm_chip *chip,
 		rc = len;
 		dev_err(&chip->dev,
 			"tpm_transmit: tpm_recv: error %d\n", rc);
-		goto out;
+		goto out_idle;
 	} else if (len < TPM_HEADER_SIZE) {
 		rc = -EFAULT;
-		goto out;
+		goto out_idle;
 	}
 
 	if (len != be32_to_cpu(header->length)) {
 		rc = -EFAULT;
-		goto out;
+		goto out_idle;
 	}
 
-	rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
-	if (rc)
-		dev_err(&chip->dev, "tpm2_commit_space: error %d\n", rc);
+out_space:
+	if (rc) {
+		tpm2_flush_space(chip);
+	} else {
+		rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
+		if (rc)
+			dev_err(&chip->dev, "tpm2_commit_space: error %d\n",
+				rc);
+	}
 
-out:
+out_idle:
 	/* may fail but do not override previous error value in rc */
 	tpm_go_idle(chip, flags);
 
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 49bca4d1e786..229ac42b644e 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -579,6 +579,7 @@  int tpm2_probe(struct tpm_chip *chip);
 int tpm2_find_cc(struct tpm_chip *chip, u32 cc);
 int tpm2_init_space(struct tpm_space *space);
 void tpm2_del_space(struct tpm_chip *chip, struct tpm_space *space);
+void tpm2_flush_space(struct tpm_chip *chip);
 int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc,
 		       u8 *cmd);
 int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
index 1131a8e7b79b..d53c882268ff 100644
--- a/drivers/char/tpm/tpm2-space.c
+++ b/drivers/char/tpm/tpm2-space.c
@@ -162,7 +162,7 @@  static int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf,
 	return 0;
 }
 
-static void tpm2_flush_space(struct tpm_chip *chip)
+void tpm2_flush_space(struct tpm_chip *chip)
 {
 	struct tpm_space *space = &chip->work_space;
 	int i;