[GIT PULL] TPM driver robustness fixes

[Rajiv Andrade]

Hi James,


The following changes since commit 2e270d84223262a38d4755c61d55f5c73ea89e56:

  Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 (2011-03-16 13:26:17 -0700)

are available in the git repository at:

  git://tpmdd.git.sourceforge.net/gitroot/tpmdd/tpmdd/ for-james

Peter Huewe (3):

      This patch changes the call of tpm_transmit by supplying the size of the userspace buffer instead of TPM_BUFSIZE

      This patch fixes information leakage to the userspace by initializing the data buffer to zero

      Since the buffer might contain security related data it might be a good idea to zero the buffer after we have copied it to userspace.

 drivers/char/tpm/tpm.c |    7 ++++---

 1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c

index 1f46f1c..c6d2cde 100644

--- a/drivers/char/tpm/tpm.c

+++ b/drivers/char/tpm/tpm.c

@@ -427,7 +427,7 @@ static ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,

     goto out;

 

 out_recv:

-    rc = chip->vendor.recv(chip, (u8 *) buf, bufsiz);

+    rc = chip->vendor.recv(chip, (u8 *) buf, TPM_BUFSIZE);

     if (rc<  0)

         dev_err(chip->dev,

             "tpm_transmit: tpm_recv: error %zd\n", rc);

@@ -980,7 +980,7 @@ int tpm_open(struct inode *inode, struct file *file)

         return -EBUSY;

     }

 

-    chip->data_buffer = kmalloc(TPM_BUFSIZE * sizeof(u8), GFP_KERNEL);

+    chip->data_buffer = kzalloc(TPM_BUFSIZE * sizeof(u8), GFP_KERNEL);

     if (chip->data_buffer == NULL) {

         clear_bit(0,&chip->is_open);

         put_device(chip->dev);

@@ -1035,7 +1035,7 @@ ssize_t tpm_write(struct file *file, const char __user *buf,

     }

 

     /* atomic tpm command send and result receive */

-    out_size = tpm_transmit(chip, chip->data_buffer, TPM_BUFSIZE);

+    out_size = tpm_transmit(chip, chip->data_buffer, in_size);

 

     atomic_set(&chip->data_pending, out_size);

     mutex_unlock(&chip->buffer_mutex);

@@ -1064,6 +1064,7 @@ ssize_t tpm_read(struct file *file, char __user *buf,

         mutex_lock(&chip->buffer_mutex);

         if (copy_to_user(buf, chip->data_buffer, ret_size))

             ret_size = -EFAULT;

+        memset(chip->data_buffer, 0, ret_size);

         mutex_unlock(&chip->buffer_mutex);

     }

 

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