Re: [PATCH v2 3/3] tpm: vtpm_proxy: Add ioctl to request locality prepended to command

[Stefan Berger]

On 05/03/2017 06:37 PM, Jarkko Sakkinen wrote:
On Fri, Apr 28, 2017 at 09:02:18AM -0400, Stefan Berger wrote:
Add an ioctl to request that the locality be prepended to every TPM
command.
Don't really understand this change. Why locality is prenpended?

Commands can be executed under locality 0-3 and for some commands it is 
important to know which locality a user may have chosen. How else should 
we convey that locality to the TPM emulator ?

Where is the ioctl declaration in this commit?

My bad, it's a flag that's being added here.


Signed-off-by: Stefan Berger <stef...@linux.vnet.ibm.com>
---
  drivers/char/tpm/tpm_vtpm_proxy.c | 18 +++++++++++++-----
  include/uapi/linux/vtpm_proxy.h   |  4 +++-
  2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c 
b/drivers/char/tpm/tpm_vtpm_proxy.c
index 48b9818..6c90e02 100644
--- a/drivers/char/tpm/tpm_vtpm_proxy.c
+++ b/drivers/char/tpm/tpm_vtpm_proxy.c
@@ -52,7 +52,8 @@ struct proxy_dev {
  };
  
  /* all supported flags */
-#define VTPM_PROXY_FLAGS_ALL  (VTPM_PROXY_FLAG_TPM2)
+#define VTPM_PROXY_FLAGS_ALL  (VTPM_PROXY_FLAG_TPM2 | \
+                              VTPM_PROXY_FLAG_PREPEND_LOCALITY)
  
  static struct workqueue_struct *workqueue;
  
@@ -77,8 +78,9 @@ static ssize_t vtpm_proxy_fops_read(struct file *filp, char __user *buf,
                                    size_t count, loff_t *off)
  {
        struct proxy_dev *proxy_dev = filp->private_data;
-       size_t len;
-       int sig, rc;
+       size_t len, offset = 0;
+       int sig, rc = 0;
One line per declaration:

size_t len;
size_t offset = 0;
int sig;
int rc = 0;

+       uint8_t locality;
  
  	sig = wait_event_interruptible(proxy_dev->wq,
                proxy_dev->req_len != 0 ||
@@ -102,7 +104,13 @@ static ssize_t vtpm_proxy_fops_read(struct file *filp, 
char __user *buf,
                return -EIO;
        }
  
-	rc = copy_to_user(buf, proxy_dev->buffer, len);
+       if (proxy_dev->flags & VTPM_PROXY_FLAG_PREPEND_LOCALITY) {
+               locality = proxy_dev->chip->locality;
+               offset = sizeof(locality);
+               rc = copy_to_user(buf, &locality, offset);
+       }
+       if (!rc)
+               rc = copy_to_user(&buf[offset], proxy_dev->buffer, len);
        memset(proxy_dev->buffer, 0, len);
        proxy_dev->req_len = 0;
  
@@ -114,7 +122,7 @@ static ssize_t vtpm_proxy_fops_read(struct file *filp, char __user *buf,
        if (rc)
                return -EFAULT;
  
-	return len;
+       return offset + len;
  }
  
  /**
diff --git a/include/uapi/linux/vtpm_proxy.h b/include/uapi/linux/vtpm_proxy.h
index 83e64e7..512a29e 100644
--- a/include/uapi/linux/vtpm_proxy.h
+++ b/include/uapi/linux/vtpm_proxy.h
@@ -22,9 +22,11 @@
  /**
   * enum vtpm_proxy_flags - flags for the proxy TPM
   * @VTPM_PROXY_FLAG_TPM2:     the proxy TPM uses TPM 2.0 protocol
+ * @VTPM_PROXY_PREPEND_LOCALITY:locality byte prepended on each command
   */
  enum vtpm_proxy_flags {
-       VTPM_PROXY_FLAG_TPM2    = 1,
+       VTPM_PROXY_FLAG_TPM2                    = 1,
+       VTPM_PROXY_FLAG_PREPEND_LOCALITY        = 2,
  };
  
  /**
--
2.4.3

/Jarkko