tpm: Wrap the buffer from the caller to tpm_buf in tpm_send()
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Message ID 20190916085008.22239-1-jarkko.sakkinen@linux.intel.com
State New
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Series
  • tpm: Wrap the buffer from the caller to tpm_buf in tpm_send()
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Commit Message

Jarkko Sakkinen Sept. 16, 2019, 8:50 a.m. UTC
tpm_send() does not give anymore the result back to the caller. This
would require another memcpy(), which kind of tells that the whole
approach is somewhat broken. Instead, as Mimi suggested, this commit
just wraps the data to the tpm_buf, and thus the result will not go to
the garbage.

Obviously this assumes from the caller that it passes large enough
buffer, which makes the whole API somewhat broken because it could be
different size than @buflen but since trusted keys is the only module
using this API right now I think that this fix is sufficient for the
moment.

In the near future the plan is to replace the parameters with a tpm_buf
created by the caller.

Reported-by: Mimi Zohar <zohar@linux.ibm.com>
Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
Cc: stable@vger.kernel.org
Fixes: 412eb585587a ("use tpm_buf in tpm_transmit_cmd() as the IO parameter")
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 drivers/char/tpm/tpm-interface.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

Comments

Jerry Snitselaar Sept. 16, 2019, 9:03 p.m. UTC | #1
On Mon Sep 16 19, Jarkko Sakkinen wrote:
>tpm_send() does not give anymore the result back to the caller. This
>would require another memcpy(), which kind of tells that the whole
>approach is somewhat broken. Instead, as Mimi suggested, this commit
>just wraps the data to the tpm_buf, and thus the result will not go to
>the garbage.
>
>Obviously this assumes from the caller that it passes large enough
>buffer, which makes the whole API somewhat broken because it could be
>different size than @buflen but since trusted keys is the only module
>using this API right now I think that this fix is sufficient for the
>moment.
>
>In the near future the plan is to replace the parameters with a tpm_buf
>created by the caller.
>
>Reported-by: Mimi Zohar <zohar@linux.ibm.com>
>Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
>Cc: stable@vger.kernel.org
>Fixes: 412eb585587a ("use tpm_buf in tpm_transmit_cmd() as the IO parameter")
>Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
>---
> drivers/char/tpm/tpm-interface.c | 8 ++------
> 1 file changed, 2 insertions(+), 6 deletions(-)
>
>diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
>index d9ace5480665..2459d36dd8cc 100644
>--- a/drivers/char/tpm/tpm-interface.c
>+++ b/drivers/char/tpm/tpm-interface.c
>@@ -358,13 +358,9 @@ int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen)
> 	if (!chip)
> 		return -ENODEV;
>
>-	rc = tpm_buf_init(&buf, 0, 0);
>-	if (rc)
>-		goto out;
>-
>-	memcpy(buf.data, cmd, buflen);
>+	buf.data = cmd;
> 	rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to a send a command");
>-	tpm_buf_destroy(&buf);
>+
> out:
> 	tpm_put_ops(chip);
> 	return rc;
>-- 
>2.20.1
>

Nothing uses the out label any longer so it should be dropped as well, but other than that...

Acked-by: Jerry Snitselaar <jsnitsel@redhat.com>
Jerry Snitselaar Sept. 16, 2019, 9:04 p.m. UTC | #2
On Mon Sep 16 19, Jerry Snitselaar wrote:
>On Mon Sep 16 19, Jarkko Sakkinen wrote:
>>tpm_send() does not give anymore the result back to the caller. This
>>would require another memcpy(), which kind of tells that the whole
>>approach is somewhat broken. Instead, as Mimi suggested, this commit
>>just wraps the data to the tpm_buf, and thus the result will not go to
>>the garbage.
>>
>>Obviously this assumes from the caller that it passes large enough
>>buffer, which makes the whole API somewhat broken because it could be
>>different size than @buflen but since trusted keys is the only module
>>using this API right now I think that this fix is sufficient for the
>>moment.
>>
>>In the near future the plan is to replace the parameters with a tpm_buf
>>created by the caller.
>>
>>Reported-by: Mimi Zohar <zohar@linux.ibm.com>
>>Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
>>Cc: stable@vger.kernel.org
>>Fixes: 412eb585587a ("use tpm_buf in tpm_transmit_cmd() as the IO parameter")
>>Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
>>---
>>drivers/char/tpm/tpm-interface.c | 8 ++------
>>1 file changed, 2 insertions(+), 6 deletions(-)
>>
>>diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
>>index d9ace5480665..2459d36dd8cc 100644
>>--- a/drivers/char/tpm/tpm-interface.c
>>+++ b/drivers/char/tpm/tpm-interface.c
>>@@ -358,13 +358,9 @@ int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen)
>>	if (!chip)
>>		return -ENODEV;
>>
>>-	rc = tpm_buf_init(&buf, 0, 0);
>>-	if (rc)
>>-		goto out;
>>-
>>-	memcpy(buf.data, cmd, buflen);
>>+	buf.data = cmd;
>>	rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to a send a command");
>>-	tpm_buf_destroy(&buf);
>>+
>>out:
>>	tpm_put_ops(chip);
>>	return rc;
>>-- 
>>2.20.1
>>
>
>Nothing uses the out label any longer so it should be dropped as well, but other than that...
>
>Acked-by: Jerry Snitselaar <jsnitsel@redhat.com>

sigh (wrong emacs macro hit), that should be:

Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Jarkko Sakkinen Sept. 17, 2019, 7:13 p.m. UTC | #3
On Mon, Sep 16, 2019 at 02:04:54PM -0700, Jerry Snitselaar wrote:
> On Mon Sep 16 19, Jerry Snitselaar wrote:
> > On Mon Sep 16 19, Jarkko Sakkinen wrote:
> > > tpm_send() does not give anymore the result back to the caller. This
> > > would require another memcpy(), which kind of tells that the whole
> > > approach is somewhat broken. Instead, as Mimi suggested, this commit
> > > just wraps the data to the tpm_buf, and thus the result will not go to
> > > the garbage.
> > > 
> > > Obviously this assumes from the caller that it passes large enough
> > > buffer, which makes the whole API somewhat broken because it could be
> > > different size than @buflen but since trusted keys is the only module
> > > using this API right now I think that this fix is sufficient for the
> > > moment.
> > > 
> > > In the near future the plan is to replace the parameters with a tpm_buf
> > > created by the caller.
> > > 
> > > Reported-by: Mimi Zohar <zohar@linux.ibm.com>
> > > Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
> > > Cc: stable@vger.kernel.org
> > > Fixes: 412eb585587a ("use tpm_buf in tpm_transmit_cmd() as the IO parameter")
> > > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> > > ---
> > > drivers/char/tpm/tpm-interface.c | 8 ++------
> > > 1 file changed, 2 insertions(+), 6 deletions(-)
> > > 
> > > diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> > > index d9ace5480665..2459d36dd8cc 100644
> > > --- a/drivers/char/tpm/tpm-interface.c
> > > +++ b/drivers/char/tpm/tpm-interface.c
> > > @@ -358,13 +358,9 @@ int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen)
> > > 	if (!chip)
> > > 		return -ENODEV;
> > > 
> > > -	rc = tpm_buf_init(&buf, 0, 0);
> > > -	if (rc)
> > > -		goto out;
> > > -
> > > -	memcpy(buf.data, cmd, buflen);
> > > +	buf.data = cmd;
> > > 	rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to a send a command");
> > > -	tpm_buf_destroy(&buf);
> > > +
> > > out:
> > > 	tpm_put_ops(chip);
> > > 	return rc;
> > > -- 
> > > 2.20.1
> > > 
> > 
> > Nothing uses the out label any longer so it should be dropped as well, but other than that...
> > 
> > Acked-by: Jerry Snitselaar <jsnitsel@redhat.com>
> 
> sigh (wrong emacs macro hit), that should be:
> 
> Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>

Thank you! I pushed the commit to master/next.

/Jarkko

Patch
diff mbox series

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index d9ace5480665..2459d36dd8cc 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -358,13 +358,9 @@  int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen)
 	if (!chip)
 		return -ENODEV;
 
-	rc = tpm_buf_init(&buf, 0, 0);
-	if (rc)
-		goto out;
-
-	memcpy(buf.data, cmd, buflen);
+	buf.data = cmd;
 	rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to a send a command");
-	tpm_buf_destroy(&buf);
+
 out:
 	tpm_put_ops(chip);
 	return rc;