app/hwcrypto/hwkey_srv.c - trusty/lk/nxp - Git at Google

 /*
  * Copyright (C) 2016-2017 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include <assert.h>
 #include <lk/compiler.h>
 #include <uapi/err.h>
 #include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>

 #include <trusty_std.h>
 #include <interface/hwkey/hwkey.h>

 #include "common.h"
 #include "uuids.h"
 #include "hwkey_srv_priv.h"

 #define TLOG_LVL      TLOG_LVL_DEFAULT
 #define TLOG_TAG      "hwkey_srv"
 #include "tlog.h"

 #define HWKEY_MAX_PAYLOAD_SIZE 2048

 struct hwkey_chan_ctx {
     tipc_event_handler_t evt_handler;
     handle_t chan;
     uuid_t uuid;
 };

 static void hwkey_port_handler(const uevent_t *ev, void *priv);
 static void hwkey_chan_handler(const uevent_t *ev, void *priv);

 static tipc_event_handler_t hwkey_port_evt_handler = {
     .proc = hwkey_port_handler,
 };

 /* Make sure that key_data and reg_data buffers are not crossing page boundary so it is
  * safe to pass them to DMA. An extra byte for req_data buf is used to zero terminate string
  * so it is OK to have it on separate page as it will never be accesed by DMA engine.
  */
 static uint8_t key_data[HWKEY_MAX_PAYLOAD_SIZE]   __attribute__((aligned(HWKEY_MAX_PAYLOAD_SIZE)));
 static uint8_t req_data[HWKEY_MAX_PAYLOAD_SIZE+1] __attribute__((aligned(HWKEY_MAX_PAYLOAD_SIZE)));

 static uint key_slot_cnt;
 static const struct hwkey_keyslot *key_slots;


 #if WITH_HWCRYPTO_UNITTEST
 /*
  *  Support for hwcrypto unittest keys should be only enabled
  *  to test hwcrypto related APIs
  */

 /* UUID of HWCRYPTO_UNITTEST application */
 static const uuid_t hwcrypto_unittest_uuid = HWCRYPTO_UNITTEST_APP_UUID;

 static uint8_t _unittest_key32[32] = "unittestkeyslotunittestkeyslotun";
 static uint32_t get_unittest_key32(const struct hwkey_keyslot *slot,
                                    uint8_t *kbuf, size_t kbuf_len, size_t *klen)
 {
     assert(kbuf);
     assert(klen);
     assert(kbuf_len >= sizeof(_unittest_key32));

     /* just return predefined key */
     memcpy(kbuf, _unittest_key32, sizeof(_unittest_key32));
     *klen = sizeof(_unittest_key32);

     return HWKEY_NO_ERROR;
 }

 static const struct hwkey_keyslot test_key_slots[] = {
     {
         .uuid = &hwcrypto_unittest_uuid,
         .key_id = "com.android.trusty.hwcrypto.unittest.key32",
         .handler = get_unittest_key32,
     },
 };
 #endif /* WITH_HWCRYPTO_UNITTEST */

 /*
  * Close specified hwkey context
  */
 static void hwkey_ctx_close(struct hwkey_chan_ctx *ctx)
 {
     close(ctx->chan);
     free(ctx);
 }

 /*
  * Send response message
  */
 static int hwkey_send_rsp(struct hwkey_chan_ctx *ctx,
                           struct hwkey_msg *rsp_hdr,
                           uint8_t *rsp_data, size_t rsp_data_len)
 {
     rsp_hdr->cmd |= HWKEY_RESP_BIT;
     return tipc_send_two_segments(ctx->chan,
                                   rsp_hdr, sizeof(*rsp_hdr),
                                   rsp_data, rsp_data_len);
 }


 static uint32_t _handle_slots(struct hwkey_chan_ctx *ctx, const char *slot_id,
                               const struct hwkey_keyslot *slots, uint slot_cnt,
                               uint8_t *kbuf, size_t kbuf_len, size_t *klen)
 {
     if (!slots)
         return HWKEY_ERR_NOT_FOUND;

     for (uint i = 0; i < slot_cnt; i++, slots++) {

         /* check key id */
         if (strcmp(slots->key_id, slot_id))
             continue;

         /* Check if the caller is allowed to get that key */
         if (memcmp(&ctx->uuid, slots->uuid, sizeof(uuid_t)) == 0) {
             if (slots->handler) {
                 return slots->handler(slots, kbuf, kbuf_len, klen);
             }
         }
     }
     return HWKEY_ERR_NOT_FOUND;
 }


 /*
  * Handle get key slot command
  */
 static int hwkey_handle_get_keyslot_cmd(struct hwkey_chan_ctx *ctx,
                                         struct hwkey_msg *hdr,
                                         const char *slot_id)
 {
     int rc;
     size_t klen = 0;

     hdr->status = _handle_slots(ctx, slot_id, key_slots, key_slot_cnt,
                                 key_data, sizeof(key_data), &klen);

 #if WITH_HWCRYPTO_UNITTEST
     if (hdr->status == HWKEY_ERR_NOT_FOUND) {
         /* also search test keys */
         hdr->status  = _handle_slots(ctx, slot_id,
                                      test_key_slots, countof(test_key_slots),
                                      key_data, sizeof(key_data), &klen);
     }
 #endif

     rc = hwkey_send_rsp(ctx, hdr, key_data, klen);
     if (klen) {
         /* sanitize key buffer */
         memset(key_data, 0, klen);
     }
     return rc;
 }

 /*
  * Handle Derive key cmd
  */
 static int hwkey_handle_derive_key_cmd(struct hwkey_chan_ctx *ctx,
                                        struct hwkey_msg *hdr,
                                        const uint8_t *ikm_data, size_t ikm_len)
 {
     int rc;
     size_t key_len = sizeof(key_data);

     /* check requested key derivation function */
     if (hdr->arg1 == HWKEY_KDF_VERSION_BEST)
         hdr->arg1 = HWKEY_KDF_VERSION_1; /* we only support V1 */

     switch (hdr->arg1) {
     case HWKEY_KDF_VERSION_1:
         hdr->status = derive_key_v1(&ctx->uuid, ikm_data, ikm_len,
                                     key_data, &key_len);
         break;

     default:
         TLOGE("%u is unsupported KDF function\n", hdr->arg1);
         key_len = 0;
         hdr->status = HWKEY_ERR_NOT_IMPLEMENTED;
     }

     rc = hwkey_send_rsp(ctx, hdr, key_data, key_len);
     if (key_len) {
         /* sanitize key buffer */
         memset(key_data, 0, key_len);
     }
     return rc;
 }

 /*
  *  Read and queue HWKEY request message
  */
 static int hwkey_chan_handle_msg(struct hwkey_chan_ctx *ctx)
 {
     int rc;
     size_t req_data_len;
     struct hwkey_msg hdr;

     rc = tipc_recv_two_segments(ctx->chan, &hdr, sizeof(hdr),
                                 req_data, sizeof(req_data) - 1);
     if (rc < 0) {
         TLOGE("failed (%d) to recv msg from chan %d\n", rc, ctx->chan);
         return rc;
     }

     /* calculate payload length */
     req_data_len = (size_t)rc - sizeof(hdr);

     /* handle it */
     switch (hdr.cmd) {
     case HWKEY_GET_KEYSLOT:
         req_data[req_data_len] = 0; /* force zero termination */
         rc = hwkey_handle_get_keyslot_cmd(ctx, &hdr, (const char *)req_data);
         break;

     case HWKEY_DERIVE:
         rc = hwkey_handle_derive_key_cmd(ctx, &hdr, req_data, req_data_len);
         memset(req_data, 0, req_data_len); /* sanitize request buffer */
         break;

     default:
         TLOGE("Unsupported request: %d\n", (int)hdr.cmd);
         hdr.status = HWKEY_ERR_NOT_IMPLEMENTED;
         rc = hwkey_send_rsp(ctx, &hdr, NULL, 0);
     }

     return rc;
 }

 /*
  *  HWKEY service channel event handler
  */
 static void hwkey_chan_handler(const uevent_t *ev, void *priv)
 {
     struct hwkey_chan_ctx *ctx = priv;

     assert(ctx);
     assert(ev->handle == ctx->chan);

     tipc_handle_chan_errors(ev);

     if (ev->event & IPC_HANDLE_POLL_HUP) {
         /* closed by peer. */
         hwkey_ctx_close(ctx);
         return;
     }

     if (ev->event & IPC_HANDLE_POLL_MSG) {
         int rc = hwkey_chan_handle_msg(ctx);
         if (rc < 0) {
             /* report an error and close channel */
             TLOGE("failed (%d) to handle event on channel %d\n",
                   rc, ev->handle);
             hwkey_ctx_close(ctx);
         }
     }
 }

 /*
  * HWKEY service port event handler
  */
 static void hwkey_port_handler(const uevent_t *ev, void *priv)
 {
     uuid_t peer_uuid;

     tipc_handle_port_errors(ev);

     if (ev->event & IPC_HANDLE_POLL_READY) {
         /* incoming connection: accept it */
         int rc = accept(ev->handle, &peer_uuid);
         if (rc < 0) {
             TLOGE("failed (%d) to accept on port %d\n", rc, ev->handle);
             return;
         }

         handle_t chan = (handle_t) rc;
         struct hwkey_chan_ctx *ctx = calloc(1, sizeof(*ctx));
         if (!ctx) {
             TLOGE("failed (%d) to allocate context on chan %d\n", rc, chan);
             close(chan);
             return;
         }

         /* init channel state */
         ctx->evt_handler.priv = ctx;
         ctx->evt_handler.proc = hwkey_chan_handler;
         ctx->chan = chan;
         ctx->uuid = peer_uuid;

         rc = set_cookie(chan, &ctx->evt_handler);
         if (rc < 0) {
             TLOGE("failed (%d) to set_cookie on chan %d\n", rc, chan);
             hwkey_ctx_close(ctx);
             return;
         }
     }
 }

 /*
  *  Install Key slot provider
  */
 void hwkey_install_keys(const struct hwkey_keyslot *keys, uint kcnt)
 {
     assert(key_slots == NULL);
     assert(key_slot_cnt == 0);
     assert(keys && kcnt);

     key_slots = keys;
     key_slot_cnt = kcnt;
 }

 /*
  *  Initialize HWKEY service
  */
 int hwkey_start_service(void)
 {
     int rc;
     handle_t port;

     TLOGI("Start HWKEY service\n");

     /* Initialize service */
     rc = port_create(HWKEY_PORT, 1, sizeof(struct hwkey_msg) + HWKEY_MAX_PAYLOAD_SIZE,
                      IPC_PORT_ALLOW_TA_CONNECT);
     if (rc < 0) {
         TLOGE("Failed (%d) to create port %s\n", rc, HWKEY_PORT);
         return rc;
     }

     port = (handle_t) rc;
     rc = set_cookie(port, &hwkey_port_evt_handler);
     if (rc) {
         TLOGE("failed (%d) to set_cookie on port %d\n", rc, port);
         close(port);
         return rc;
     }

     return NO_ERROR;
 }
	/*
	* Copyright (C) 2016-2017 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include <assert.h>
	#include <lk/compiler.h>
	#include <uapi/err.h>
	#include <stddef.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>

	#include <trusty_std.h>
	#include <interface/hwkey/hwkey.h>

	#include "common.h"
	#include "uuids.h"
	#include "hwkey_srv_priv.h"

	#define TLOG_LVL TLOG_LVL_DEFAULT
	#define TLOG_TAG "hwkey_srv"
	#include "tlog.h"

	#define HWKEY_MAX_PAYLOAD_SIZE 2048

	struct hwkey_chan_ctx {
	tipc_event_handler_t evt_handler;
	handle_t chan;
	uuid_t uuid;
	};

	static void hwkey_port_handler(const uevent_t ev, void priv);
	static void hwkey_chan_handler(const uevent_t ev, void priv);

	static tipc_event_handler_t hwkey_port_evt_handler = {
	.proc = hwkey_port_handler,
	};

	/* Make sure that key_data and reg_data buffers are not crossing page boundary so it is
	* safe to pass them to DMA. An extra byte for req_data buf is used to zero terminate string
	* so it is OK to have it on separate page as it will never be accesed by DMA engine.
	*/
	static uint8_t key_data[HWKEY_MAX_PAYLOAD_SIZE] __attribute__((aligned(HWKEY_MAX_PAYLOAD_SIZE)));
	static uint8_t req_data[HWKEY_MAX_PAYLOAD_SIZE+1] __attribute__((aligned(HWKEY_MAX_PAYLOAD_SIZE)));

	static uint key_slot_cnt;
	static const struct hwkey_keyslot *key_slots;


	#if WITH_HWCRYPTO_UNITTEST
	/*
	* Support for hwcrypto unittest keys should be only enabled
	* to test hwcrypto related APIs
	*/

	/* UUID of HWCRYPTO_UNITTEST application */
	static const uuid_t hwcrypto_unittest_uuid = HWCRYPTO_UNITTEST_APP_UUID;

	static uint8_t _unittest_key32[32] = "unittestkeyslotunittestkeyslotun";
	static uint32_t get_unittest_key32(const struct hwkey_keyslot *slot,
	uint8_t kbuf, size_t kbuf_len, size_t klen)
	{
	assert(kbuf);
	assert(klen);
	assert(kbuf_len >= sizeof(_unittest_key32));

	/* just return predefined key */
	memcpy(kbuf, _unittest_key32, sizeof(_unittest_key32));
	*klen = sizeof(_unittest_key32);

	return HWKEY_NO_ERROR;
	}

	static const struct hwkey_keyslot test_key_slots[] = {
	{
	.uuid = &hwcrypto_unittest_uuid,
	.key_id = "com.android.trusty.hwcrypto.unittest.key32",
	.handler = get_unittest_key32,
	},
	};
	#endif /* WITH_HWCRYPTO_UNITTEST */

	/*
	* Close specified hwkey context
	*/
	static void hwkey_ctx_close(struct hwkey_chan_ctx *ctx)
	{
	close(ctx->chan);
	free(ctx);
	}

	/*
	* Send response message
	*/
	static int hwkey_send_rsp(struct hwkey_chan_ctx *ctx,
	struct hwkey_msg *rsp_hdr,
	uint8_t *rsp_data, size_t rsp_data_len)
	{
	rsp_hdr->cmd \|= HWKEY_RESP_BIT;
	return tipc_send_two_segments(ctx->chan,
	rsp_hdr, sizeof(*rsp_hdr),
	rsp_data, rsp_data_len);
	}


	static uint32_t _handle_slots(struct hwkey_chan_ctx ctx, const char slot_id,
	const struct hwkey_keyslot *slots, uint slot_cnt,
	uint8_t kbuf, size_t kbuf_len, size_t klen)
	{
	if (!slots)
	return HWKEY_ERR_NOT_FOUND;

	for (uint i = 0; i < slot_cnt; i++, slots++) {

	/* check key id */
	if (strcmp(slots->key_id, slot_id))
	continue;

	/* Check if the caller is allowed to get that key */
	if (memcmp(&ctx->uuid, slots->uuid, sizeof(uuid_t)) == 0) {
	if (slots->handler) {
	return slots->handler(slots, kbuf, kbuf_len, klen);
	}
	}
	}
	return HWKEY_ERR_NOT_FOUND;
	}


	/*
	* Handle get key slot command
	*/
	static int hwkey_handle_get_keyslot_cmd(struct hwkey_chan_ctx *ctx,
	struct hwkey_msg *hdr,
	const char *slot_id)
	{
	int rc;
	size_t klen = 0;

	hdr->status = _handle_slots(ctx, slot_id, key_slots, key_slot_cnt,
	key_data, sizeof(key_data), &klen);

	#if WITH_HWCRYPTO_UNITTEST
	if (hdr->status == HWKEY_ERR_NOT_FOUND) {
	/* also search test keys */
	hdr->status = _handle_slots(ctx, slot_id,
	test_key_slots, countof(test_key_slots),
	key_data, sizeof(key_data), &klen);
	}
	#endif

	rc = hwkey_send_rsp(ctx, hdr, key_data, klen);
	if (klen) {
	/* sanitize key buffer */
	memset(key_data, 0, klen);
	}
	return rc;
	}

	/*
	* Handle Derive key cmd
	*/
	static int hwkey_handle_derive_key_cmd(struct hwkey_chan_ctx *ctx,
	struct hwkey_msg *hdr,
	const uint8_t *ikm_data, size_t ikm_len)
	{
	int rc;
	size_t key_len = sizeof(key_data);

	/* check requested key derivation function */
	if (hdr->arg1 == HWKEY_KDF_VERSION_BEST)
	hdr->arg1 = HWKEY_KDF_VERSION_1; /* we only support V1 */

	switch (hdr->arg1) {
	case HWKEY_KDF_VERSION_1:
	hdr->status = derive_key_v1(&ctx->uuid, ikm_data, ikm_len,
	key_data, &key_len);
	break;

	default:
	TLOGE("%u is unsupported KDF function\n", hdr->arg1);
	key_len = 0;
	hdr->status = HWKEY_ERR_NOT_IMPLEMENTED;
	}

	rc = hwkey_send_rsp(ctx, hdr, key_data, key_len);
	if (key_len) {
	/* sanitize key buffer */
	memset(key_data, 0, key_len);
	}
	return rc;
	}

	/*
	* Read and queue HWKEY request message
	*/
	static int hwkey_chan_handle_msg(struct hwkey_chan_ctx *ctx)
	{
	int rc;
	size_t req_data_len;
	struct hwkey_msg hdr;

	rc = tipc_recv_two_segments(ctx->chan, &hdr, sizeof(hdr),
	req_data, sizeof(req_data) - 1);
	if (rc < 0) {
	TLOGE("failed (%d) to recv msg from chan %d\n", rc, ctx->chan);
	return rc;
	}

	/* calculate payload length */
	req_data_len = (size_t)rc - sizeof(hdr);

	/* handle it */
	switch (hdr.cmd) {
	case HWKEY_GET_KEYSLOT:
	req_data[req_data_len] = 0; /* force zero termination */
	rc = hwkey_handle_get_keyslot_cmd(ctx, &hdr, (const char *)req_data);
	break;

	case HWKEY_DERIVE:
	rc = hwkey_handle_derive_key_cmd(ctx, &hdr, req_data, req_data_len);
	memset(req_data, 0, req_data_len); /* sanitize request buffer */
	break;

	default:
	TLOGE("Unsupported request: %d\n", (int)hdr.cmd);
	hdr.status = HWKEY_ERR_NOT_IMPLEMENTED;
	rc = hwkey_send_rsp(ctx, &hdr, NULL, 0);
	}

	return rc;
	}

	/*
	* HWKEY service channel event handler
	*/
	static void hwkey_chan_handler(const uevent_t ev, void priv)
	{
	struct hwkey_chan_ctx *ctx = priv;

	assert(ctx);
	assert(ev->handle == ctx->chan);

	tipc_handle_chan_errors(ev);

	if (ev->event & IPC_HANDLE_POLL_HUP) {
	/* closed by peer. */
	hwkey_ctx_close(ctx);
	return;
	}

	if (ev->event & IPC_HANDLE_POLL_MSG) {
	int rc = hwkey_chan_handle_msg(ctx);
	if (rc < 0) {
	/* report an error and close channel */
	TLOGE("failed (%d) to handle event on channel %d\n",
	rc, ev->handle);
	hwkey_ctx_close(ctx);
	}
	}
	}

	/*
	* HWKEY service port event handler
	*/
	static void hwkey_port_handler(const uevent_t ev, void priv)
	{
	uuid_t peer_uuid;

	tipc_handle_port_errors(ev);

	if (ev->event & IPC_HANDLE_POLL_READY) {
	/* incoming connection: accept it */
	int rc = accept(ev->handle, &peer_uuid);
	if (rc < 0) {
	TLOGE("failed (%d) to accept on port %d\n", rc, ev->handle);
	return;
	}

	handle_t chan = (handle_t) rc;
	struct hwkey_chan_ctx ctx = calloc(1, sizeof(ctx));
	if (!ctx) {
	TLOGE("failed (%d) to allocate context on chan %d\n", rc, chan);
	close(chan);
	return;
	}

	/* init channel state */
	ctx->evt_handler.priv = ctx;
	ctx->evt_handler.proc = hwkey_chan_handler;
	ctx->chan = chan;
	ctx->uuid = peer_uuid;

	rc = set_cookie(chan, &ctx->evt_handler);
	if (rc < 0) {
	TLOGE("failed (%d) to set_cookie on chan %d\n", rc, chan);
	hwkey_ctx_close(ctx);
	return;
	}
	}
	}

	/*
	* Install Key slot provider
	*/
	void hwkey_install_keys(const struct hwkey_keyslot *keys, uint kcnt)
	{
	assert(key_slots == NULL);
	assert(key_slot_cnt == 0);
	assert(keys && kcnt);

	key_slots = keys;
	key_slot_cnt = kcnt;
	}

	/*
	* Initialize HWKEY service
	*/
	int hwkey_start_service(void)
	{
	int rc;
	handle_t port;

	TLOGI("Start HWKEY service\n");

	/* Initialize service */
	rc = port_create(HWKEY_PORT, 1, sizeof(struct hwkey_msg) + HWKEY_MAX_PAYLOAD_SIZE,
	IPC_PORT_ALLOW_TA_CONNECT);
	if (rc < 0) {
	TLOGE("Failed (%d) to create port %s\n", rc, HWKEY_PORT);
	return rc;
	}

	port = (handle_t) rc;
	rc = set_cookie(port, &hwkey_port_evt_handler);
	if (rc) {
	TLOGE("failed (%d) to set_cookie on port %d\n", rc, port);
	close(port);
	return rc;
	}

	return NO_ERROR;
	}