avb: add support for named persistent values

AVB 2.0 spec. revision 1.1 introduces support for named persistent values
that must be tamper evident and allows AVB to store arbitrary key-value
pairs [1].

Introduce implementation of two additional AVB operations
read_persistent_value()/write_persistent_value() for retrieving/storing
named persistent values.

Correspondent pull request in the OP-TEE OS project repo [2].

[1]: https://android.googlesource.com/platform/external/avb/+/android-9.0.0_r22
[2]: https://github.com/OP-TEE/optee_os/pull/2699

Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Igor Opaniuk <igor.opaniuk@gmail.com>

1 files changed, 102 insertions, 19 deletions

diff --git a/drivers/tee/sandbox.c b/drivers/tee/sandbox.c
index ccddb03e73..a136bc9609 100644
--- a/drivers/tee/sandbox.c
+++ b/drivers/tee/sandbox.c
@@ -14,6 +14,7 @@
  * available.
  */
 
+static const u32 pstorage_max = 16;
 /**
  * struct ta_entry - TA entries
  * @uuid:		UUID of an emulated TA
@@ -24,8 +25,11 @@
  */
 struct ta_entry {
 	struct tee_optee_ta_uuid uuid;
-	u32 (*open_session)(uint num_params, struct tee_param *params);
-	u32 (*invoke_func)(u32 func, uint num_params, struct tee_param *params);
+	u32 (*open_session)(struct udevice *dev, uint num_params,
+			    struct tee_param *params);
+	u32 (*invoke_func)(struct udevice *dev,
+			   u32 func, uint num_params,
+			   struct tee_param *params);
 };
 
 #ifdef CONFIG_OPTEE_TA_AVB
@@ -59,10 +63,8 @@ bad_params:
 	return TEE_ERROR_BAD_PARAMETERS;
 }
 
-static u64 ta_avb_rollback_indexes[TA_AVB_MAX_ROLLBACK_LOCATIONS];
-static u32 ta_avb_lock_state;
-
-static u32 ta_avb_open_session(uint num_params, struct tee_param *params)
+static u32 ta_avb_open_session(struct udevice *dev, uint num_params,
+			       struct tee_param *params)
 {
 	/*
 	 * We don't expect additional parameters when opening a session to
@@ -73,12 +75,17 @@ static u32 ta_avb_open_session(uint num_params, struct tee_param *params)
 			    num_params, params);
 }
 
-static u32 ta_avb_invoke_func(u32 func, uint num_params,
+static u32 ta_avb_invoke_func(struct udevice *dev, u32 func, uint num_params,
 			      struct tee_param *params)
 {
+	struct sandbox_tee_state *state = dev_get_priv(dev);
+	ENTRY e, *ep;
+	char *name;
 	u32 res;
 	uint slot;
 	u64 val;
+	char *value;
+	u32 value_sz;
 
 	switch (func) {
 	case TA_AVB_CMD_READ_ROLLBACK_INDEX:
@@ -91,12 +98,12 @@ static u32 ta_avb_invoke_func(u32 func, uint num_params,
 			return res;
 
 		slot = params[0].u.value.a;
-		if (slot >= ARRAY_SIZE(ta_avb_rollback_indexes)) {
+		if (slot >= ARRAY_SIZE(state->ta_avb_rollback_indexes)) {
 			printf("Rollback index slot out of bounds %u\n", slot);
 			return TEE_ERROR_BAD_PARAMETERS;
 		}
 
-		val = ta_avb_rollback_indexes[slot];
+		val = state->ta_avb_rollback_indexes[slot];
 		params[1].u.value.a = val >> 32;
 		params[1].u.value.b = val;
 		return TEE_SUCCESS;
@@ -111,16 +118,16 @@ static u32 ta_avb_invoke_func(u32 func, uint num_params,
 			return res;
 
 		slot = params[0].u.value.a;
-		if (slot >= ARRAY_SIZE(ta_avb_rollback_indexes)) {
+		if (slot >= ARRAY_SIZE(state->ta_avb_rollback_indexes)) {
 			printf("Rollback index slot out of bounds %u\n", slot);
 			return TEE_ERROR_BAD_PARAMETERS;
 		}
 
 		val = (u64)params[1].u.value.a << 32 | params[1].u.value.b;
-		if (val < ta_avb_rollback_indexes[slot])
+		if (val < state->ta_avb_rollback_indexes[slot])
 			return TEE_ERROR_SECURITY;
 
-		ta_avb_rollback_indexes[slot] = val;
+		state->ta_avb_rollback_indexes[slot] = val;
 		return TEE_SUCCESS;
 
 	case TA_AVB_CMD_READ_LOCK_STATE:
@@ -132,7 +139,7 @@ static u32 ta_avb_invoke_func(u32 func, uint num_params,
 		if (res)
 			return res;
 
-		params[0].u.value.a = ta_avb_lock_state;
+		params[0].u.value.a = state->ta_avb_lock_state;
 		return TEE_SUCCESS;
 
 	case TA_AVB_CMD_WRITE_LOCK_STATE:
@@ -144,13 +151,64 @@ static u32 ta_avb_invoke_func(u32 func, uint num_params,
 		if (res)
 			return res;
 
-		if (ta_avb_lock_state != params[0].u.value.a) {
-			ta_avb_lock_state = params[0].u.value.a;
-			memset(ta_avb_rollback_indexes, 0,
-			       sizeof(ta_avb_rollback_indexes));
+		if (state->ta_avb_lock_state != params[0].u.value.a) {
+			state->ta_avb_lock_state = params[0].u.value.a;
+			memset(state->ta_avb_rollback_indexes, 0,
+			       sizeof(state->ta_avb_rollback_indexes));
 		}
 
 		return TEE_SUCCESS;
+	case TA_AVB_CMD_READ_PERSIST_VALUE:
+		res = check_params(TEE_PARAM_ATTR_TYPE_MEMREF_INPUT,
+				   TEE_PARAM_ATTR_TYPE_MEMREF_INOUT,
+				   TEE_PARAM_ATTR_TYPE_NONE,
+				   TEE_PARAM_ATTR_TYPE_NONE,
+				   num_params, params);
+		if (res)
+			return res;
+
+		name = params[0].u.memref.shm->addr;
+
+		value = params[1].u.memref.shm->addr;
+		value_sz = params[1].u.memref.size;
+
+		e.key = name;
+		e.data = NULL;
+		hsearch_r(e, FIND, &ep, &state->pstorage_htab, 0);
+		if (!ep)
+			return TEE_ERROR_ITEM_NOT_FOUND;
+
+		value_sz = strlen(ep->data);
+		memcpy(value, ep->data, value_sz);
+
+		return TEE_SUCCESS;
+	case TA_AVB_CMD_WRITE_PERSIST_VALUE:
+		res = check_params(TEE_PARAM_ATTR_TYPE_MEMREF_INPUT,
+				   TEE_PARAM_ATTR_TYPE_MEMREF_INPUT,
+				   TEE_PARAM_ATTR_TYPE_NONE,
+				   TEE_PARAM_ATTR_TYPE_NONE,
+				   num_params, params);
+		if (res)
+			return res;
+
+		name = params[0].u.memref.shm->addr;
+
+		value = params[1].u.memref.shm->addr;
+		value_sz = params[1].u.memref.size;
+
+		e.key = name;
+		e.data = NULL;
+		hsearch_r(e, FIND, &ep, &state->pstorage_htab, 0);
+		if (ep)
+			hdelete_r(e.key, &state->pstorage_htab, 0);
+
+		e.key = name;
+		e.data = value;
+		hsearch_r(e, ENTER, &ep, &state->pstorage_htab, 0);
+		if (!ep)
+			return TEE_ERROR_OUT_OF_MEMORY;
+
+		return TEE_SUCCESS;
 
 	default:
 		return TEE_ERROR_NOT_SUPPORTED;
@@ -225,7 +283,7 @@ static int sandbox_tee_open_session(struct udevice *dev,
 		return 0;
 	}
 
-	arg->ret = ta->open_session(num_params, params);
+	arg->ret = ta->open_session(dev, num_params, params);
 	arg->ret_origin = TEE_ORIGIN_TRUSTED_APP;
 
 	if (!arg->ret) {
@@ -261,7 +319,7 @@ static int sandbox_tee_invoke_func(struct udevice *dev,
 		return -EINVAL;
 	}
 
-	arg->ret = ta->invoke_func(arg->func, num_params, params);
+	arg->ret = ta->invoke_func(dev, arg->func, num_params, params);
 	arg->ret_origin = TEE_ORIGIN_TRUSTED_APP;
 
 	return 0;
@@ -285,6 +343,29 @@ static int sandbox_tee_shm_unregister(struct udevice *dev, struct tee_shm *shm)
 	return 0;
 }
 
+static int sandbox_tee_remove(struct udevice *dev)
+{
+	struct sandbox_tee_state *state = dev_get_priv(dev);
+
+	hdestroy_r(&state->pstorage_htab);
+
+	return 0;
+}
+
+static int sandbox_tee_probe(struct udevice *dev)
+{
+	struct sandbox_tee_state *state = dev_get_priv(dev);
+	/*
+	 * With this hastable we emulate persistent storage,
+	 * which should contain persistent values
+	 * between different sessions/command invocations.
+	 */
+	if (!hcreate_r(pstorage_max, &state->pstorage_htab))
+		return TEE_ERROR_OUT_OF_MEMORY;
+
+	return 0;
+}
+
 static const struct tee_driver_ops sandbox_tee_ops = {
 	.get_version = sandbox_tee_get_version,
 	.open_session = sandbox_tee_open_session,
@@ -305,4 +386,6 @@ U_BOOT_DRIVER(sandbox_tee) = {
 	.of_match = sandbox_tee_match,
 	.ops = &sandbox_tee_ops,
 	.priv_auto_alloc_size = sizeof(struct sandbox_tee_state),
+	.probe = sandbox_tee_probe,
+	.remove = sandbox_tee_remove,
 };