Fix isDecryptable crashing on empty data argument, add unknown as result for bad signature or filesize, minor formatting fixes for extendedlist output in user and batchmodes

GUI-CLI Protocol.md

@@ -348,7 +348,7 @@ CLI:
 ```
 
 The list contains the `name` of a file and its `size` in kByte. <br />
-The `encrypted` field contains information wether the file is `unencrypted`, `decryptable` or `undecryptable`.
+The `encrypted` field contains information wether the file is `unknown` in case of bad signature or file size, `unencrypted`, `decryptable` or `undecryptable`.
 
 ## 3. Disconnecting and exiting
 

cli/include/fileman.h

@@ -68,7 +68,7 @@ private:
 	void writeEnc(const std::vector<char> data);
 	const char signature[4] = {'C', 'C', 'A', 'T'};
 
-	enum decryptability { plaintext, decryptable, undecryptable };
+	enum decryptability { unknown, plaintext, decryptable, undecryptable };
 	decryptability isDecryptable(const std::vector<char> data);
 
 public:

cli/src/batchioman.cpp

@@ -439,11 +439,13 @@ std::string BatchIoMan::printExtendedlist(Json::Value root) {
 				std::string encrypted = val["encrypted"].asString();
 				std::string decryptable;
 				if (encrypted == "decryptable") {
-					decryptable = "yes        ";
+					decryptable = "yes          ";
 				} else if (encrypted == "undecryptable") {
-					decryptable = "no         ";
+					decryptable = "no           ";
+				} else if (encrypted == "unknown") {
+					decryptable = "unknown      ";
 				} else {
-					decryptable = "plaintext  ";
+					decryptable = "plaintext    ";
 				}
 				std::string progress = std::to_string(val["progress"].asInt());
 				std::string file = val["name"].asString();

cli/src/fileman.cpp

@@ -256,9 +256,10 @@ void FileMan::putListData(vector<Json::Value> files) {
 			fileInfo["size"] = file["size"];
 
 			string headString = file["head"].asString();
-			std::cerr << "checking decryptability of file " << file["name"].asString() << std::endl;
 			decryptability decr = isDecryptable(base64::decodeVector(headString));
-			if (decr == FileMan::undecryptable) {
+			if (decr == FileMan::unknown) {
+				fileInfo["encrypted"] = "unknown";
+			} else if (decr == FileMan::undecryptable) {
 				fileInfo["encrypted"] = "undecryptable";
 			} else if (decr == FileMan::decryptable) {
 				fileInfo["encrypted"] = "decryptable";
@@ -457,8 +458,8 @@ FileMan::decryptability FileMan::isDecryptable(const vector<char> data) {
 	unsigned char plain[sizeof(signature)] = {0}, *cipher;
 	int plainlen;
 	// check if signature matches in plaintext
-	if (memcmp(data.data(), signature, sizeof(signature))) {
-		// it does not
+	if (data.size() < sizeof(signature) || memcmp(data.data(), signature, sizeof(signature))) {
+		// either size or signature dont match
 		if (data.size() >= (sizeof(signature) + sizeof(iv) + sizeof(tag)) && keyenabled) {
 			// enough data, key is enabled
 			memcpy(iv, data.data(), sizeof(iv));
@@ -484,8 +485,8 @@ FileMan::decryptability FileMan::isDecryptable(const vector<char> data) {
 				return decryptable;
 			}
 		}
-		// no key enabled or decryption failed, assume undecryptable
-		return undecryptable;
+		// size mismatch or no key enabled, consider unknown
+		return unknown;
 	}
 	// it does, assume plaintext
 	return plaintext;

cli/src/userioman.cpp

@@ -232,11 +232,13 @@ void UserIoMan::printExtendedlist(Json::Value root) {
 				std::string encrypted = val["encrypted"].asString();
 				std::string decryptable;
 				if (encrypted == "decryptable") {
-					decryptable = "\033[32myes\033[0m        "; // "yes" in green
+					decryptable = "\033[32myes\033[0m          "; // "yes" in green
 				} else if (encrypted == "undecryptable") {
-					decryptable = "\033[31mno\033[0m         "; // "no" in red
+					decryptable = "\033[31mno\033[0m           "; // "no" in red
+				} else if (encrypted == "unknown") {
+					decryptable = "unknown      "; // "no" in red
 				} else {
-					decryptable = "plaintext  ";
+					decryptable = "plaintext    ";
 				}
 				std::string progress = std::to_string(val["progress"].asInt());
 				std::string file = val["name"].asString();