From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:33688 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752799AbdKVKQu (ORCPT ); Wed, 22 Nov 2017 05:16:50 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexander Steffen , Jarkko Sakkinen Subject: [PATCH 4.13 26/35] tpm-dev-common: Reject too short writes Date: Wed, 22 Nov 2017 11:12:20 +0100 Message-Id: <20171122101139.402336199@linuxfoundation.org> In-Reply-To: <20171122101137.661212603@linuxfoundation.org> References: <20171122101137.661212603@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexander Steffen 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 Reviewed-by: Jarkko Sakkinen Tested-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen Signed-off-by: Greg Kroah-Hartman --- 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.