Code Review 6947917: Error in basic authentication when user name and password are long

[Chris Hegarty]

Michael,

A minor change to the encoder used for Basic Authentication.

Webrev:
   http://cr.openjdk.java.net/~chegar/6947917/webrev.00/webrev/

The Basic Authentication implementation, 
sun.net.www.protocol.http.BasicAuthentication, uses a 
sun.misc.BASE64Encoder to encode the Authentication headers field value. 
The sun.misc.BASE64Encoder class encodes 57 bytes per line. This results 
in a maximum of 57/3 * 4, or 76, characters per output line (not 
counting the line termination) before writing a LineSuffix, i.e. a 
newline character.

With long long usernames and/or passwords it is possible to generate a 
header value with more than 76 characters, therefore causing a newline 
character to be returned as part of the header value. This violates the 
HTTP spec for Message Headers, which states that "Header fields can be 
extended over multiple lines by preceding each extra line with at least 
one SP or HT.".

We should increase the number of bytes per line for the encoder used for 
Basic Authentication, similar to what is done in  NegotiateAuthentication.

-Chris.