From: Alexander Steffen Alexander.Steffen@infineon.com

commit ee70bc1e7b63ac8023c9ff9475d8741e397316e7 upstream.

tpm_transmit() does not offer an explicit interface to indicate the number of valid bytes in the communication buffer. Instead, it relies on the commandSize field in the TPM header that is encoded within the buffer. Therefore, ensure that a) enough data has been written to the buffer, so that the commandSize field is present and b) the commandSize field does not announce more data than has been written to the buffer.

This should have been fixed with CVE-2011-1161 long ago, but apparently a correct version of that patch never made it into the kernel.

Cc: stable@vger.kernel.org Signed-off-by: Alexander Steffen Alexander.Steffen@infineon.com Reviewed-by: Jarkko Sakkinen jarkko.sakkinen@linux.intel.com Tested-by: Jarkko Sakkinen jarkko.sakkinen@linux.intel.com Signed-off-by: Jarkko Sakkinen jarkko.sakkinen@linux.intel.com --- drivers/char/tpm/tpm-dev.c | 6 ++++++ 1 file changed, 6 insertions(+)

diff --git a/drivers/char/tpm/tpm-dev.c b/drivers/char/tpm/tpm-dev.c index 912ad30be585..65b824954bdc 100644 --- a/drivers/char/tpm/tpm-dev.c +++ b/drivers/char/tpm/tpm-dev.c @@ -136,6 +136,12 @@ static ssize_t tpm_write(struct file *file, const char __user *buf, return -EFAULT; }

+ if (in_size < 6 || + in_size < be32_to_cpu(*((__be32 *) (priv->data_buffer + 2)))) { + mutex_unlock(&priv->buffer_mutex); + return -EINVAL; + } + /* atomic tpm command send and result receive. We only hold the ops * lock during this period so that the tpm can be unregistered even if * the char dev is held open.