Fix shift overflow

Avoid undefined behavior by casting uint8_t to uint32_t before shifting
by 24 bits.

bootloader/usb.c

@@ -334,7 +334,7 @@ static void hid_rx_callback(usbd_device *dev, uint8_t ep)
 		}
 		// struct.unpack(">HL") => msg, size
 		msg_id = (buf[3] << 8) + buf[4];
-		msg_size = (buf[5] << 24) + (buf[6] << 16) + (buf[7] << 8) + buf[8];
+		msg_size = ((uint32_t) buf[5] << 24) + (buf[6] << 16) + (buf[7] << 8) + buf[8];
 	}
 
 	if (flash_state == STATE_READY || flash_state == STATE_OPEN) {

firmware/crypto.c

@@ -82,7 +82,7 @@ uint32_t deser_length(const uint8_t *in, uint32_t *out)
 		return 1 + 2;
 	}
 	if (in[0] == 254) {
-		*out = in[1] + (in[2] << 8) + (in[3] << 16) + (in[4] << 24);
+		*out = in[1] + (in[2] << 8) + (in[3] << 16) + ((uint32_t) in[4] << 24);
 		return 1 + 4;
 	}
 	*out = 0; // ignore 64 bit

firmware/fsm.c

@@ -1010,10 +1010,10 @@ void fsm_msgSignIdentity(SignIdentity *msg)
 
 	uint32_t address_n[5];
 	address_n[0] = 0x80000000 | 13;
-	address_n[1] = 0x80000000 | hash[ 0] | (hash[ 1] << 8) | (hash[ 2] << 16) | (hash[ 3] << 24);
-	address_n[2] = 0x80000000 | hash[ 4] | (hash[ 5] << 8) | (hash[ 6] << 16) | (hash[ 7] << 24);
-	address_n[3] = 0x80000000 | hash[ 8] | (hash[ 9] << 8) | (hash[10] << 16) | (hash[11] << 24);
-	address_n[4] = 0x80000000 | hash[12] | (hash[13] << 8) | (hash[14] << 16) | (hash[15] << 24);
+	address_n[1] = 0x80000000 | hash[ 0] | (hash[ 1] << 8) | (hash[ 2] << 16) | ((uint32_t) hash[ 3] << 24);
+	address_n[2] = 0x80000000 | hash[ 4] | (hash[ 5] << 8) | (hash[ 6] << 16) | ((uint32_t) hash[ 7] << 24);
+	address_n[3] = 0x80000000 | hash[ 8] | (hash[ 9] << 8) | (hash[10] << 16) | ((uint32_t) hash[11] << 24);
+	address_n[4] = 0x80000000 | hash[12] | (hash[13] << 8) | (hash[14] << 16) | ((uint32_t) hash[15] << 24);
 
 	const char *curve = SECP256K1_NAME;
 	if (msg->has_ecdsa_curve_name) {
@@ -1086,10 +1086,10 @@ void fsm_msgGetECDHSessionKey(GetECDHSessionKey *msg)
 
 	uint32_t address_n[5];
 	address_n[0] = 0x80000000 | 17;
-	address_n[1] = 0x80000000 | hash[ 0] | (hash[ 1] << 8) | (hash[ 2] << 16) | (hash[ 3] << 24);
-	address_n[2] = 0x80000000 | hash[ 4] | (hash[ 5] << 8) | (hash[ 6] << 16) | (hash[ 7] << 24);
-	address_n[3] = 0x80000000 | hash[ 8] | (hash[ 9] << 8) | (hash[10] << 16) | (hash[11] << 24);
-	address_n[4] = 0x80000000 | hash[12] | (hash[13] << 8) | (hash[14] << 16) | (hash[15] << 24);
+	address_n[1] = 0x80000000 | hash[ 0] | (hash[ 1] << 8) | (hash[ 2] << 16) | ((uint32_t) hash[ 3] << 24);
+	address_n[2] = 0x80000000 | hash[ 4] | (hash[ 5] << 8) | (hash[ 6] << 16) | ((uint32_t) hash[ 7] << 24);
+	address_n[3] = 0x80000000 | hash[ 8] | (hash[ 9] << 8) | (hash[10] << 16) | ((uint32_t) hash[11] << 24);
+	address_n[4] = 0x80000000 | hash[12] | (hash[13] << 8) | (hash[14] << 16) | ((uint32_t) hash[15] << 24);
 
 	const char *curve = SECP256K1_NAME;
 	if (msg->has_ecdsa_curve_name) {

firmware/messages.c

@@ -259,7 +259,7 @@ void msg_read_common(char type, const uint8_t *buf, int len)
 			return;
 		}
 		msg_id = (buf[3] << 8) + buf[4];
-		msg_size = (buf[5] << 24)+ (buf[6] << 16) + (buf[7] << 8) + buf[8];
+		msg_size = ((uint32_t) buf[5] << 24)+ (buf[6] << 16) + (buf[7] << 8) + buf[8];
 
 		fields = MessageFields(type, 'i', msg_id);
 		if (!fields) { // unknown message
@@ -333,7 +333,7 @@ void msg_read_tiny(const uint8_t *buf, int len)
 		return;
 	}
 	uint16_t msg_id = (buf[3] << 8) + buf[4];
-	uint32_t msg_size = (buf[5] << 24) + (buf[6] << 16) + (buf[7] << 8) + buf[8];
+	uint32_t msg_size = ((uint32_t) buf[5] << 24) + (buf[6] << 16) + (buf[7] << 8) + buf[8];
 	if (msg_size > 64 || len - msg_size < 9) {
 		return;
 	}