| From ee70bc1e7b63ac8023c9ff9475d8741e397316e7 Mon Sep 17 00:00:00 2001 |
| From: Alexander Steffen <Alexander.Steffen@infineon.com> |
| Date: Fri, 8 Sep 2017 17:21:32 +0200 |
| Subject: tpm-dev-common: Reject too short writes |
| |
| 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. |
| |
| 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> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/char/tpm/tpm-dev-common.c | 6 ++++++ |
| 1 file changed, 6 insertions(+) |
| |
| --- a/drivers/char/tpm/tpm-dev-common.c |
| +++ b/drivers/char/tpm/tpm-dev-common.c |
| @@ -110,6 +110,12 @@ ssize_t tpm_common_write(struct file *fi |
| 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. |