[jira] [Created] (GUACAMOLE-615) Incorrect instruction element length handle because of Java's char type

["Aiden Luo (JIRA)" <ji...@apache.org>]

Aiden Luo created GUACAMOLE-615:
-----------------------------------

             Summary: Incorrect instruction element length handle because of Java's char type
                 Key: GUACAMOLE-615
                 URL: https://issues.apache.org/jira/browse/GUACAMOLE-615
             Project: Guacamole
          Issue Type: Bug
          Components: guacamole-common
    Affects Versions: 0.9.14
            Reporter: Aiden Luo


The definition of guacamole instruction:
{quote}The Guacamole protocol consists of instructions. Each instruction is a comma-delimited list followed by a terminating semicolon, where the first element of the list is the instruction opcode, and all following elements are the arguments for that instruction:

OPCODE,ARG1,ARG2,ARG3,...;


 Each element of the list has a positive decimal integer length prefix separated by the value of the element by a period. This length denotes the number of Unicode characters in the value of the element, which is encoded in UTF-8:

 

LENGTH.VALUE
{quote}
Which means the element's values will be encoded in UTF-8。That means we must use correct UTF-8 encoder/decoder to handle the instruction. But in guacamole-common, the parser use Java's char type to parse which only can store partial Unicode char. 

Problem code [https://github.com/apache/guacamole-client/blob/master/guacamole-common/src/main/java/org/apache/guacamole/protocol/GuacamoleParser.java#L164]  

 
{code:java}
if (state == State.PARSING_CONTENT && charsParsed + elementLength + 1 <= length) {

// Read element
String element = new String(chunk, offset + charsParsed, elementLength);
charsParsed += elementLength;
elementLength = 0;
...{code}
In the code above, bytes of a unicode char may not equal to a java char.

I also check the guacamole-server implementation, all work fine.

Correct code [https://github.com/apache/guacamole-server/blob/master/src/libguac/parser.c#L113]
{code:java}
/* Advance to next character */
parser->__element_length--;
char_buffer += char_length;{code}
 



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