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Subject: [PATCH v5] Add virtio rpmb device specification
It is a virtio based RPMB (Replay Protected Memory Block) device. Signed-off-by: Yang Huang <yang.huang@intel.com> Reviewed-by: Bing Zhu <bing.zhu@intel.com> Reviewed-by: Tomas Winkler <tomas.winkler@intel.com> v4 -> v5: 1. Add description on the mapping between block_count and virtio buffers. 2. Update "Driver Requirements: Device Operation". v3 -> v4: 1. Remove multiple RPMB targets. 2. Remove NVMe RPMB. 3. typos fix. 4. Some wording changes for better understanding. 5. Add conformance. --- conformance.tex | 20 ++++- content.tex | 1 + introduction.tex | 6 ++ virtio-rpmb.tex | 244 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 270 insertions(+), 1 deletion(-) create mode 100644 virtio-rpmb.tex diff --git a/conformance.tex b/conformance.tex index 0ac58aa..4e8d4ae 100644 --- a/conformance.tex +++ b/conformance.tex @@ -22,7 +22,7 @@ \section{Conformance Targets}\label{sec:Conformance / Conformance Targets} \begin{itemize} \item Clause \ref{sec:Conformance / Device Conformance}. \item One of clauses \ref{sec:Conformance / Device Conformance / PCI Device Conformance}, \ref{sec:Conformance / Device Conformance / MMIO Device Conformance} or \ref{sec:Conformance / Device Conformance / Channel I/O Device Conformance}. - \item One of clauses \ref{sec:Conformance / Device Conformance / Network Device Conformance}, \ref{sec:Conformance / Device Conformance / Block Device Conformance}, \ref{sec:Conformance / Device Conformance / Console Device Conformance}, \ref{sec:Conformance / Device Conformance / Entropy Device Conformance}, \ref{sec:Conformance / Device Conformance / Traditional Memory Balloon Device Conformance}, \ref{sec:Conformance / Device Conformance / SCSI Host Device Conformance}, \ref{sec:Conformance / Device Conformance / Input Device Conformance}, \ref{sec:Conformance / Device Conformance / Crypto Device Conformance} or \ref{sec:Conformance / Device Conformance / Socket Device Conformance}. + \item One of clauses \ref{sec:Conformance / Device Conformance / Network Device Conformance}, \ref{sec:Conformance / Device Conformance / Block Device Conformance}, \ref{sec:Conformance / Device Conformance / Console Device Conformance}, \ref{sec:Conformance / Device Conformance / Entropy Device Conformance}, \ref{sec:Conformance / Device Conformance / Traditional Memory Balloon Device Conformance}, \ref{sec:Conformance / Device Conformance / SCSI Host Device Conformance}, \ref{sec:Conformance / Device Conformance / Input Device Conformance}, \ref{sec:Conformance / Device Conformance / Crypto Device Conformance}, \ref{sec:Conformance / Device Conformance / Socket Device Conformance} or \ref{sec:Conformance / Device Conformance / RPMB Device Conformance}. \item Clause \ref{sec:Conformance / Legacy Interface: Transitional Device and Transitional Driver Conformance}. \end{itemize} \end{description} @@ -183,6 +183,14 @@ \section{Conformance Targets}\label{sec:Conformance / Conformance Targets} \item \ref{drivernormative:Device Types / Socket Device / Device Operation / Device Events} \end{itemize} +\conformance{\subsection}{RPMB Driver Conformance}\label{sec:Conformance / Driver Conformance / RPMB Driver Conformance} + +A RPMB driver MUST conform to the following normative statements: + +\begin{itemize} +\item \ref{drivernormative:Device Types / RPMB Device / Device Operation} +\end{itemize} + \conformance{\section}{Device Conformance}\label{sec:Conformance / Device Conformance} A device MUST conform to the following normative statements: @@ -338,6 +346,16 @@ \section{Conformance Targets}\label{sec:Conformance / Conformance Targets} \item \ref{devicenormative:Device Types / Socket Device / Device Operation / Receive and Transmit} \end{itemize} +\conformance{\subsection}{RPMB Device Conformance}\label{sec:Conformance / Device Conformance / RPMB Device Conformance} + +An RPMB device MUST conform to the following normative statements: + +\begin{itemize} +\item \ref{devicenormative:Device Types / RPMB Device / Device Initialization} +\item \ref{devicenormative:Device Types / RPMB Device / Device Operation / Device Operation: Request Queue} +\item \ref{devicenormative:Device Types / RPMB Device / Device Operation} +\end{itemize} + \conformance{\section}{Legacy Interface: Transitional Device and Transitional Driver Conformance}\label{sec:Conformance / Legacy Interface: Transitional Device and Transitional Driver Conformance} A conformant implementation MUST be either transitional or non-transitional, see \ref{intro:Legacy diff --git a/content.tex b/content.tex index ee0d7c9..2573bd5 100644 --- a/content.tex +++ b/content.tex @@ -5677,6 +5677,7 @@ \subsubsection{Legacy Interface: Framing Requirements}\label{sec:Device \input{virtio-input.tex} \input{virtio-crypto.tex} \input{virtio-vsock.tex} +\input{virtio-rpmb.tex} \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits} diff --git a/introduction.tex b/introduction.tex index c96acf9..b304777 100644 --- a/introduction.tex +++ b/introduction.tex @@ -60,6 +60,12 @@ \section{Normative References}\label{sec:Normative References} \phantomsection\label{intro:SCSI MMC}\textbf{[SCSI MMC]} & SCSI Multimedia Commands, \newline\url{http://www.t10.org/cgi-bin/ac.pl?t=f&f=mmc6r00.pdf}\\ + \phantomsection\label{intro:eMMC}\textbf{[eMMC]} & + eMMC Electrical Standard (5.1), + \newline\url{https://www.jedec.org/standards-documents/docs/jesd84-b51}\\ + \phantomsection\label{intro:UFS}\textbf{[UFS]} & + UNIVERSAL FLASH STORAGE (UFS), Version 3.0, + \newline\url{https://www.jedec.org/standards-documents/docs/jesd220c}\\ \end{longtable} diff --git a/virtio-rpmb.tex b/virtio-rpmb.tex new file mode 100644 index 0000000..7bea6fd --- /dev/null +++ b/virtio-rpmb.tex @@ -0,0 +1,244 @@ +\section{RPMB Device}\label{sec:Device Types / RPMB Device} + +virtio-rpmb is a virtio based RPMB (Replay Protected Memory Block) +device. It is used as a tamper-resistant and anti-replay storage. +The device is driven via requests including read, write, get write +counter and program key, which are submitted via a request queue. +This section relies on definitions from paragraph 6.6.22 of +\hyperref[intro:eMMC]{eMMC} and 12.4 of \hyperref[intro:UFS]{UFS}. +\subsection{Device ID}\label{sec:Device Types / RPMB Device / Device ID} + +28 + +\subsection{Virtqueues}\label{sec:Device Types / RPMB Device / Virtqueues} + +\begin{description} +\item[0] requestq +\end{description} + +\subsection{Feature bits}\label{sec:Device Types / RPMB Device / Feature bits} + +None. + +\subsection{Device configuration layout}\label{sec:Device Types / RPMB Device / Device configuration layout} + +All fields of this configuration are always available and read-only for the driver. + +\begin{lstlisting} +struct virtio_rpmb_config { + u8 capacity; + u8 max_wr_cnt; + u8 max_rd_cnt; +} +\end{lstlisting} + +\begin{description} +\item[\field{capacity}] is the capacity of the device (expressed in 128KB units). + The values MUST range between 0x00 and 0x80 inclusive. +\item[\field{max_wr_cnt and max_rd_cnt}] are the maximum numbers of RPMB + block count (256B) that can be performed to device in one request. 0 implies + no limitation. +\end{description} + +\devicenormative{\subsection}{Device Initialization}{Device Types / RPMB Device / Device Initialization} + +\begin{enumerate} +\item The virtqueue is initialized. +\item The device capacity MUST be initialized to a multiple of 128Kbytes and up to + 16Mbytes. +\end{enumerate} + +\subsection{Device Operation}\label{sec:Device Types / RPMB Device / Device Operation} + +The operation of a virtio RPMB device is driven by the requests placed on the virtqueue. + The type of request can be program key (VIRTIO_RPMB_REQ_PROGRAM_KEY), + get write counter (VIRTIO_RPMB_REQ_GET_WRITE_COUNTER), + write (VIRTIO_RPMB_REQ_DATA_WRITE), and read (VIRTIO_RPMB_REQ_DATA_READ). + A program key or write request can also combine with a + result read (VIRTIO_RPMB_REQ_RESULT_READ) for a returned result. + +\begin{lstlisting} +/* RPMB Request Types */ +#define VIRTIO_RPMB_REQ_PROGRAM_KEY 0x0001 +#define VIRTIO_RPMB_REQ_GET_WRITE_COUNTER 0x0002 +#define VIRTIO_RPMB_REQ_DATA_WRITE 0x0003 +#define VIRTIO_RPMB_REQ_DATA_READ 0x0004 +#define VIRTIO_RPMB_REQ_RESULT_READ 0x0005 +\end{lstlisting} + +\subsubsection{Device Operation: Request Queue}\label{sec:Device Types / RPMB Device / Device Operation / Device Operation: Request Queue} + +The request information is delivered in RPMB frame. +The frame is in size of 512B. + +\begin{lstlisting} +struct virtio_rpmb_frame { + u8 stuff[196]; + u8 key_mac[32]; + u8 data[256]; + u8 nonce[16]; + be32 write_counter; + be16 address; + be16 block_count; + be16 result; + be16 req_resp; +}; + +/* RPMB Response Types */ +#define VIRTIO_RPMB_RESP_PROGRAM_KEY 0x0100 +#define VIRTIO_RPMB_RESP_GET_COUNTER 0x0200 +#define VIRTIO_RPMB_RESP_DATA_WRITE 0x0300 +#define VIRTIO_RPMB_RESP_DATA_READ 0x0400 + +/* RPMB Operation Results */ +#define VIRTIO_RPMB_RES_OK 0x0000 +#define VIRTIO_RPMB_RES_GENERAL_FAILURE 0x0001 +#define VIRTIO_RPMB_RES_AUTH_FAILURE 0x0002 +#define VIRTIO_RPMB_RES_COUNT_FAILURE 0x0003 +#define VIRTIO_RPMB_RES_ADDR_FAILURE 0x0004 +#define VIRTIO_RPMB_RES_WRITE_FAILURE 0x0005 +#define VIRTIO_RPMB_RES_READ_FAILURE 0x0006 +#define VIRTIO_RPMB_RES_NO_AUTH_KEY 0x0007 +#define VIRTIO_RPMB_RES_WRITE_COUNTER_EXPIRED 0x0080 +\end{lstlisting} + +\begin{description} +\item[\field{stuff}] Padding for the frame. + +\item[\field{key_mac}] is the authentication key or the message + authentication code (MAC) depending on the request/response type. + If the request is VIRTIO_RPMB_REQ_PROGRAM_KEY, it's used as an + authentication key. Otherwise, it's used as MAC. The MAC is calculated + using HMAC SHA-256. It takes as input a key and a message. The key + used for the MAC calculation is always the 256-bit RPMB authentication + key. The message used as input to the MAC calculation is the + concatenation of the fields in the RPMB frames excluding stuff bytes + and the MAC itself. + +\item[\field{data}] is used to be written or read via authenticated + read/write access. It's fixed 256B. + +\item[\field{nonce}] is a random number generated by the user for the read + or get write counter requests and copied to the response by the device. + It's used for anti-replay protection. + +\item[\field{writer_counter}] is the counter value for the total amount of + the successful authenticated data write requests. + +\item[\field{address}] is the address of the data to be written to or read + from the RPMB virtio device. It is the number of the accessed + half sector (256B). + +\item[\field{block_count}] is the number of blocks (256B) requested to be + read/written. It's limited by \field{max_wr_cnt} or \field{max_rd_cnt}. + For RPMB read request, one virtio buffer including request command and + the subsequent [\field{block_count}] virtio buffers for response data + are placed in the queue. + For RPMB write request, [\field{block_count}] virtio buffers including + request command and data are placed in the queue. + +\item[\field{result}] includes information about the status of access made + to the device. It is written by the device. + +\item[\field{req_resp}] is the type of request or response, to/from the device. +\end{description} + +\devicenormative{\paragraph}{Device Operation: Request Queue}{Device Types / RPMB Device / Device Operation / Device Operation: Request Queue} + +The device MUST parse the request from the request queue and emulate the behaviors described in paragraph +6.6.22 of \hyperref[intro:eMMC]{eMMC} or 12.4 of \hyperref[intro:UFS]{UFS}: + +\begin{description} + +\item[VIRTIO_RPMB_REQ_PROGRAM_KEY] If block count has not been set to 1 + then VIRTIO_RPMB_RES_GENERAL_FAILURE is responded. If the programming of + authentication key fails then the returned result is VIRTIO_RPMB_RES_WRITE_FAILURE. + If some other error occurs then returned result is VIRTIO_RPMB_RES_GENERAL_FAILURE. + The \field{req_resp} value VIRTIO_RPMB_RESP_PROGRAM_KEY corresponds to + the key programming request. + + If VIRTIO_RPMB_REQ_RESULT_READ is requested, the device returns the RPMB frame + with the response (VIRTIO_RPMB_RESP_PROGRAM_KEY), the calculated MAC and the result. + +\item[VIRTIO_RPMB_REQ_GET_WRITE_COUNTE] If the authentication key is not yet + programmed then VIRTIO_RPMB_RES_NO_AUTH_KEY is returned in \field{result}. + If block count has not been set to 1 then VIRTIO_RPMB_RES_GENERAL_FAILURE + SHOULD be responded. + + The device returns the RPMB frame with the response (VIRTIO_RPMB_RESP_GET_COUNTER), + the writer counter, a copy of the nonce received in the request, the calculated + MAC and the result. + +\item[VIRTIO_RPMB_REQ_DATA_WRITE] If the authentication key is not yet programmed + then VIRTIO_RPMB_RES_NO_AUTH_KEY is returned in \field{result}. If block count + is zero or greater than \field{max_wr_cnt} then VIRTIO_RPMB_RES_GENERAL_FAILURE + MUST be responded. The device MUST check whether the write counter has expired. + If the write counter is expired then sets the \field{result} to + VIRTIO_RPMB_RES_WRITE_COUNTER_EXPIRED. If there is an error in the address + (out of range) then the \field{result} is set to VIRTIO_RPMB_RES_ADDR_FAILURE. + The device MUST calculate the MAC taking authentication key and frame as input, + and compares this with the MAC in the request. If the two MACâs are different + then VIRTIO_RPMB_RES_AUTH_FAILURE is returned. + + If the writer counter in the request is different from the one maintained + by the device then VIRTIO_RPMB_RES_COUNT_FAILURE is returned in \field{result}. + If the MAC and write counter comparisons are successful then the write request + is considered to be authenticated. The data from the request are written to the + address indicated in the request and the write counter is incremented by 1. + If the write fails then the returned result is VIRTIO_RPMB_RES_WRITE_FAILURE. + If some other error occurs during the write procedure then the returned result + is VIRTIO_RPMB_RES_GENERAL_FAILURE. + + If VIRTIO_RPMB_REQ_RESULT_READ is requested, the device returns the RPMB data + frame with the response (VIRTIO_RPMB_RESP_DATA_WRITE), the incremented counter value, + the data address, the calculated MAC and the result. + +\item[VIRTIO_RPMB_REQ_DATA_READ] If the authentication key is not yet programmed + then VIRTIO_RPMB_RES_NO_AUTH_KEY is returned in \field{result}. If block count + has not been set to 1 then VIRTIO_RPMB_RES_GENERAL_FAILURE MUST be responded. + If there is an error in the address (out of range) then the \field{result} is + set to VIRTIO_RPMB_RES_ADDR_FAILURE. If data fetch from addressed location inside + device fails then the returned result is VIRTIO_RPMB_RES_READ_FAILURE. If some + other error occurs during the read procedure then the returned result is + VIRTIO_RPMB_RES_GENERAL_FAILURE. + + The device returns the RPMB frame with the response (VIRTIO_RPMB_RESP_DATA_READ), + the block count, a copy of the nonce received in the request, the address, + the data, the calculated MAC and the result. + +\item[VIRTIO_RPMB_REQ_RESULT_READ] It is used following with + VIRTIO_RPMB_REQ_PROGRAM_KEY or VIRTIO_RPMB_REQ_DATA_WRITE request types for + returned result in one or multiple RPMB frames. If it's not requested, the device + will not return result frame to the driver. If block count has not been set to + 1 of VIRTIO_RPMB_REQ_RESULT_READ request, then VIRTIO_RPMB_RES_GENERAL_FAILURE + SHALL be indicated. + +\end{description} +If an authentication key was programmed successfully, the device SHALL return with a MAC for any operation requests. + +\drivernormative{\subsubsection}{Device Operation}{Device Types / RPMB Device / Device Operation} + +The RPMB frames MUST not be packed by the driver. +The driver MUST configure, initialize and format virtqueue for the RPMB requests received from its caller, then send to the device. + +\devicenormative{\subsubsection}{Device Operation}{Device Types / RPMB Device / Device Operation} + +The virtio-rpmb device could be backed in a number of ways. It SHOULD + keep consistent behaviors with hardware as described in paragraph + 6.6.22 of \hyperref[intro:eMMC]{eMMC} or 12.4 of \hyperref[intro:UFS]{UFS}. + Some elements are maintained by the device: +\begin{enumerate} +\item The device maintains a one-time programmable authentication key. + It cannot be overwritten, erased or read. The key is used to + authenticate the accesses when MAC is calculated. This key MUST be + kept regardless of device reset or reboot. +\item The device maintains a read-only monotonic write counter. It MUST + be initialized to zero and added by one automatically along with + successful write operation. The value cannot be reset. After + the counter has reached its maximum value 0xFFFF FFFF, it will + not be incremented anymore. This counter MUST be kept regardless + of device reset or reboot. +\item The device maintains the data for read/write via authenticated + access. +\end{enumerate} + -- 2.7.4
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