This implements the first handshake of the device initialisation which
is the programming of the device key. This can only be done once
per-device.
Currently there is no persistence for the device key and other
metadata such as the write count. This will be added later.
[TODO: clarify the spec if we should respond immediately or on request]
Signed-off-by: Alex Bennée <alex.bennee@xxxxxxxxxx>
---
tools/vhost-user-rpmb/main.c | 299 +++++++++++++++++++++++++++++++++--
1 file changed, 286 insertions(+), 13 deletions(-)
diff --git a/tools/vhost-user-rpmb/main.c b/tools/vhost-user-rpmb/main.c
index 64bd7e79f573..9c98f6916f6f 100644
--- a/tools/vhost-user-rpmb/main.c
+++ b/tools/vhost-user-rpmb/main.c
@@ -22,10 +22,14 @@
#include <sys/stat.h>
#include <sys/mman.h>
#include <unistd.h>
+#include <endian.h>
+#include <assert.h>
#include "contrib/libvhost-user/libvhost-user-glib.h"
#include "contrib/libvhost-user/libvhost-user.h"
+#include "hmac_sha256.h"
+
#ifndef container_of
#define container_of(ptr, type, member) ({ \
const typeof(((type *) 0)->member) *__mptr = (ptr); \
@@ -57,6 +61,31 @@ enum {
/* These structures are defined in the specification */
#define KiB (1UL << 10)
#define MAX_RPMB_SIZE (KiB * 128 * 256)
+#define RPMB_KEY_MAC_SIZE 32
+
+/* 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
+
+/* 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
struct virtio_rpmb_config {
uint8_t capacity;
@@ -64,9 +93,13 @@ struct virtio_rpmb_config {
uint8_t max_rd_cnt;
};
+/*
+ * This is based on the JDEC standard and not the currently not
+ * up-streamed NVME standard.
+ */
struct virtio_rpmb_frame {
uint8_t stuff[196];
- uint8_t key_mac[32];
+ uint8_t key_mac[RPMB_KEY_MAC_SIZE];
uint8_t data[256];
uint8_t nonce[16];
/* remaining fields are big-endian */
@@ -75,7 +108,7 @@ struct virtio_rpmb_frame {
uint16_t block_count;
uint16_t result;
uint16_t req_resp;
-};
+} __attribute__((packed));
/*
* Structure to track internal state of RPMB Device
@@ -87,15 +120,63 @@ typedef struct VuRpmb {
GMainLoop *loop;
int flash_fd;
void *flash_map;
+ uint8_t *key;
+ uint16_t last_result;
+ uint16_t last_reqresp;
} VuRpmb;
-struct virtio_rpmb_ctrl_command {
- VuVirtqElement elem;
- VuVirtq *vq;
- struct virtio_rpmb_frame frame;
- uint32_t error;
- bool finished;
-};
+/* refer to util/iov.c */
+static size_t vrpmb_iov_size(const struct iovec *iov,
+ const unsigned int iov_cnt)
+{
+ size_t len;
+ unsigned int i;
+
+ len = 0;
+ for (i = 0; i < iov_cnt; i++) {
+ len += iov[i].iov_len;
+ }
+ return len;
+}
+
+
+static size_t vrpmb_iov_to_buf(const struct iovec *iov, const unsigned int iov_cnt,
+ size_t offset, void *buf, size_t bytes)
+{
+ size_t done;
+ unsigned int i;
+ for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) {
+ if (offset < iov[i].iov_len) {
+ size_t len = MIN(iov[i].iov_len - offset, bytes - done);
+ memcpy(buf + done, iov[i].iov_base + offset, len);
+ done += len;
+ offset = 0;
+ } else {
+ offset -= iov[i].iov_len;
+ }
+ }
+ assert(offset == 0);
+ return done;
+}
+
+static size_t vrpmb_iov_from_buf(const struct iovec *iov, unsigned int iov_cnt,
+ size_t offset, const void *buf, size_t bytes)
+{
+ size_t done;
+ unsigned int i;
+ for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) {
+ if (offset < iov[i].iov_len) {
+ size_t len = MIN(iov[i].iov_len - offset, bytes - done);
+ memcpy(iov[i].iov_base + offset, buf + done, len);
+ done += len;
+ offset = 0;
+ } else {
+ offset -= iov[i].iov_len;
+ }
+ }
+ assert(offset == 0);
+ return done;
+}
static void vrpmb_panic(VuDev *dev, const char *msg)
{
@@ -142,19 +223,211 @@ vrpmb_set_config(VuDev *dev, const uint8_t *data,
return 0;
}
+/*
+ * vrpmb_update_mac_in_frame:
+ *
+ * From the spec:
+ * 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.
+ *
+ * The code to do this has been lifted from the optee supplicant code
+ * which itself uses a 3 clause BSD chunk of code.
+ */
+
+static void vrpmb_update_mac_in_frame(VuRpmb *r, struct virtio_rpmb_frame *frm)
+{
+ hmac_sha256_ctx ctx;
+ static const int dlen = (sizeof(struct virtio_rpmb_frame) -
+ offsetof(struct virtio_rpmb_frame, data));
+
+ hmac_sha256_init(&ctx, r->key, RPMB_KEY_MAC_SIZE);
+ hmac_sha256_update(&ctx, frm->data, dlen);
+ hmac_sha256_final(&ctx, &frm->key_mac[0], 32);
+}
+
+/*
+ * Handlers for individual control messages
+ */
+
+/*
+ * vrpmb_handle_program_key:
+ *
+ * Program the device with our key. The spec is a little hazzy on if
+ * we respond straight away or we wait for the user to send a
+ * VIRTIO_RPMB_REQ_RESULT_READ request.
+ */
+static void vrpmb_handle_program_key(VuDev *dev, struct virtio_rpmb_frame *frame)
+{
+ VuRpmb *r = container_of(dev, VuRpmb, dev.parent);
+
+ /*
+ * Run the checks from:
+ * 5.12.6.1.1 Device Requirements: Device Operation: Program Key
+ */
+ r->last_reqresp = VIRTIO_RPMB_RESP_PROGRAM_KEY;
+
+ /* Fail if already programmed */
+ if (r->key) {
+ g_debug("key already programmed");
+ r->last_result = VIRTIO_RPMB_RES_WRITE_FAILURE;
+ } else if (be16toh(frame->block_count) != 1) {
+ g_debug("weird block counts (%d)", frame->block_count);
+ r->last_result = VIRTIO_RPMB_RES_GENERAL_FAILURE;
+ } else {
+ r->key = g_memdup(&frame->key_mac[0], RPMB_KEY_MAC_SIZE);
+ r->last_result = VIRTIO_RPMB_RES_OK;
+ }
+
+ g_info("%s: req_resp = %x, result = %x", __func__,
+ r->last_reqresp, r->last_result);
+ return;
+}
+
+/*
+ * Return the result of the last message. This is only valid if the
+ * previous message was VIRTIO_RPMB_REQ_PROGRAM_KEY or
+ * VIRTIO_RPMB_REQ_DATA_WRITE.
+ *
+ * The frame should be freed once sent.
+ */
+static struct virtio_rpmb_frame * vrpmb_handle_result_read(VuDev *dev)
+{
+ VuRpmb *r = container_of(dev, VuRpmb, dev.parent);
+ struct virtio_rpmb_frame *resp = g_new0(struct virtio_rpmb_frame, 1);
+
+ if (r->last_reqresp == VIRTIO_RPMB_RESP_PROGRAM_KEY ||
+ r->last_reqresp == VIRTIO_RPMB_REQ_DATA_WRITE) {
+ resp->result = htobe16(r->last_result);
+ resp->req_resp = htobe16(r->last_reqresp);
+ } else {
+ resp->result = htobe16(VIRTIO_RPMB_RES_GENERAL_FAILURE);
+ }
+
+ /* calculate HMAC */
+ if (!r->key) {
+ resp->result = htobe16(VIRTIO_RPMB_RES_GENERAL_FAILURE);
+ } else {
+ vrpmb_update_mac_in_frame(r, resp);
+ }
+
+ g_info("%s: result = %x req_resp = %x", __func__,
+ be16toh(resp->result),
+ be16toh(resp->req_resp));
+ return resp;
+}
+
+static void fmt_bytes(GString *s, uint8_t *bytes, int len)
+{
+ int i;
+ for (i = 0; i < len; i++) {
+ if (i % 16 == 0) {
+ g_string_append_c(s, '\n');
+ }
+ g_string_append_printf(s, "%x ", bytes[i]);
+ }
+}
+
+static void vrpmb_dump_frame(struct virtio_rpmb_frame *frame)
+{
+ g_autoptr(GString) s = g_string_new("frame: ");
+
+ g_string_append_printf(s, " %p\n", frame);
+ g_string_append_printf(s, "key_mac:");
+ fmt_bytes(s, (uint8_t *) &frame->key_mac[0], 32);
+ g_string_append_printf(s, "\ndata:");
+ fmt_bytes(s, (uint8_t *) &frame->data, 256);
+ g_string_append_printf(s, "\nnonce:");
+ fmt_bytes(s, (uint8_t *) &frame->nonce, 16);
+ g_string_append_printf(s, "\nwrite_counter: %d\n",
+ be32toh(frame->write_counter));
+ g_string_append_printf(s, "address: %#04x\n", be16toh(frame->address));
+ g_string_append_printf(s, "block_count: %d\n", be16toh(frame->block_count));
+ g_string_append_printf(s, "result: %d\n", be16toh(frame->result));
+ g_string_append_printf(s, "req_resp: %d\n", be16toh(frame->req_resp));
+
+ g_debug("%s: %s\n", __func__, s->str);
+}
+
static void
vrpmb_handle_ctrl(VuDev *dev, int qidx)
{
VuVirtq *vq = vu_get_queue(dev, qidx);
- struct virtio_rpmb_ctrl_command *cmd = NULL;
+ struct virtio_rpmb_frame *frames = NULL;
for (;;) {
- cmd = vu_queue_pop(dev, vq, sizeof(struct virtio_rpmb_ctrl_command));
- if (!cmd) {
+ VuVirtqElement *elem;
+ size_t len, frame_sz = sizeof(struct virtio_rpmb_frame);
+ int n;
+
+ elem = vu_queue_pop(dev, vq, sizeof(VuVirtqElement));
+ if (!elem) {
break;
}
+ g_debug("%s: got queue (in %d, out %d)", __func__,
+ elem->in_num, elem->out_num);
- g_debug("un-handled cmd: %p", cmd);
+ len = vrpmb_iov_size(elem->out_sg, elem->out_num);
+ frames = g_realloc(frames, len);
+ vrpmb_iov_to_buf(elem->out_sg, elem->out_num, 0, frames, len);
+
+ if (len % frame_sz != 0) {
+ g_warning("%s: incomplete frames %zu/%zu != 0\n",
+ __func__, len, frame_sz);
+ }
+
+ for (n = 0; n < len / frame_sz; n++) {
+ struct virtio_rpmb_frame *f = &frames[n];
+ struct virtio_rpmb_frame *resp = NULL;
+ uint16_t req_resp = be16toh(f->req_resp);
+ bool responded = false;
+
+ if (debug) {
+ g_info("req_resp=%x", req_resp);
+ vrpmb_dump_frame(f);
+ }
+
+ switch (req_resp) {
+ case VIRTIO_RPMB_REQ_PROGRAM_KEY:
+ vrpmb_handle_program_key(dev, f);
+ break;
+ case VIRTIO_RPMB_REQ_RESULT_READ:
+ if (!responded) {
+ resp = vrpmb_handle_result_read(dev);
+ } else {
+ g_warning("%s: already sent a response in this set of frames",
+ __func__);
+ }
+ break;
+ default:
+ g_debug("un-handled request: %x", f->req_resp);
+ break;
+ }
+
+ /*
+ * Do we have a frame to send back?
+ */
+ if (resp) {
+ g_debug("sending response frame: %p", resp);
+ if (debug) {
+ vrpmb_dump_frame(resp);
+ }
+ len = vrpmb_iov_from_buf(elem->in_sg,
+ elem->in_num, 0, resp, sizeof(*resp));
+ if (len != sizeof(*resp)) {
+ g_critical("%s: response size incorrect %zu vs %zu",
+ __func__, len, sizeof(*resp));
+ } else {
+ vu_queue_push(dev, vq, elem, len);
+ vu_queue_notify(dev, vq);
+ responded = true;
+ }
+
+ g_free(resp);
+ }
+ }
}
}
--
2.20.1
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