From f17a0a85e06bf9e1e3320e6b2bb3874c55bdf882 Mon Sep 17 00:00:00 2001
From: Saleem Rashid <trezor@saleemrashid.com>
Date: Sat, 16 Dec 2017 19:15:54 +0000
Subject: [PATCH] fsm: Add NEMDecryptMessage

---
 firmware/fsm.c                   | 66 ++++++++++++++++++++++++++++++++
 firmware/fsm.h                   |  1 +
 firmware/protob/messages.options |  6 +++
 vendor/trezor-crypto             |  2 +-
 4 files changed, 74 insertions(+), 1 deletion(-)

diff --git a/firmware/fsm.c b/firmware/fsm.c
index 9a7b852..34211be 100644
--- a/firmware/fsm.c
+++ b/firmware/fsm.c
@@ -1431,6 +1431,72 @@ void fsm_msgNEMSignTx(NEMSignTx *msg) {
 	layoutHome();
 }
 
+void fsm_msgNEMDecryptMessage(NEMDecryptMessage *msg)
+{
+	RESP_INIT(NEMDecryptedMessage);
+
+	CHECK_INITIALIZED
+
+	CHECK_PARAM(nem_network_name(msg->network), _("Invalid NEM network"));
+	CHECK_PARAM(msg->has_payload, _("No payload provided"));
+	CHECK_PARAM(msg->payload.size >= NEM_ENCRYPTED_PAYLOAD_SIZE(0), _("Invalid encrypted payload"));
+	CHECK_PARAM(msg->has_public_key, _("No public key provided"));
+	CHECK_PARAM(msg->public_key.size == 32, _("Invalid public key"));
+
+	char address[NEM_ADDRESS_SIZE + 1];
+	nem_get_address(msg->public_key.bytes, msg->network, address);
+
+	layoutNEMDialog(&bmp_icon_question,
+		_("Cancel"),
+		_("Confirm"),
+		_("Decrypt message"),
+		_("Confirm address?"),
+		address);
+	if (!protectButton(ButtonRequestType_ButtonRequest_Other, false)) {
+		fsm_sendFailure(FailureType_Failure_ActionCancelled, NULL);
+		layoutHome();
+		return;
+	}
+
+	CHECK_PIN
+
+	HDNode *node = fsm_getDerivedNode(ED25519_KECCAK_NAME, msg->address_n, msg->address_n_count);
+	if (!node) return;
+
+	const uint8_t *salt = msg->payload.bytes;
+	uint8_t *iv = &msg->payload.bytes[NEM_SALT_SIZE];
+
+	const uint8_t *payload = &msg->payload.bytes[NEM_SALT_SIZE + AES_BLOCK_SIZE];
+	size_t size = msg->payload.size - NEM_SALT_SIZE - AES_BLOCK_SIZE;
+
+	// hdnode_nem_decrypt mutates the IV, so this will modify msg
+	bool ret = hdnode_nem_decrypt(node,
+			msg->public_key.bytes,
+			iv,
+			salt,
+			payload,
+			size,
+			resp->payload.bytes);
+	if (!ret) {
+		fsm_sendFailure(FailureType_Failure_ProcessError, _("Failed to decrypt payload"));
+		layoutHome();
+		return;
+	}
+
+	resp->has_payload = true;
+	resp->payload.size = NEM_DECRYPTED_SIZE(resp->payload.bytes, size);
+
+	layoutNEMTransferPayload(resp->payload.bytes, resp->payload.size, true);
+	if (!protectButton(ButtonRequestType_ButtonRequest_Other, false)) {
+		fsm_sendFailure(FailureType_Failure_ActionCancelled, NULL);
+		layoutHome();
+		return;
+	}
+
+	msg_write(MessageType_MessageType_NEMDecryptedMessage, resp);
+	layoutHome();
+}
+
 void fsm_msgCosiCommit(CosiCommit *msg)
 {
 	RESP_INIT(CosiCommitment);
diff --git a/firmware/fsm.h b/firmware/fsm.h
index 41f2cb1..b91129a 100644
--- a/firmware/fsm.h
+++ b/firmware/fsm.h
@@ -68,6 +68,7 @@ void fsm_msgEthereumVerifyMessage(EthereumVerifyMessage *msg);
 
 void fsm_msgNEMGetAddress(NEMGetAddress *msg);
 void fsm_msgNEMSignTx(NEMSignTx *msg);
+void fsm_msgNEMDecryptMessage(NEMDecryptMessage *msg);
 
 void fsm_msgCosiCommit(CosiCommit *msg);
 void fsm_msgCosiSign(CosiSign *msg);
diff --git a/firmware/protob/messages.options b/firmware/protob/messages.options
index cbd4f00..e7aaffc 100644
--- a/firmware/protob/messages.options
+++ b/firmware/protob/messages.options
@@ -150,6 +150,12 @@ NEMAddress.address			max_size:41
 NEMSignedTx.data			max_size:2048
 NEMSignedTx.signature			max_size:64
 
+NEMDecryptMessage.address_n		max_count:8
+NEMDecryptMessage.public_key		max_size:32
+NEMDecryptMessage.payload		max_size:320
+
+NEMDecryptedMessage.payload		max_size:256
+
 CosiCommit.address_n			max_count:8
 CosiCommit.data				max_size:32
 
diff --git a/vendor/trezor-crypto b/vendor/trezor-crypto
index 764cc4c..74e74f5 160000
--- a/vendor/trezor-crypto
+++ b/vendor/trezor-crypto
@@ -1 +1 @@
-Subproject commit 764cc4c6e8ef32e7e1a77f0496ae090f11a36def
+Subproject commit 74e74f5eed886ff871dc1fb36088e4b465917689