[NET-624] SubnetInfo#toCidrNotation - a wrong format subnet mask is allowed

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0
• Fix Version/s: 3.7
• Assignee: Unassigned
• Reporter: Makoto Sakaguchi
• Created: 09/Mar/17 21:32
• Updated: 06/Aug/20 12:27
• Resolved: 10/Mar/17 23:34

Description

An IPv4 subnet mask, which is also the network mask, must consist of a set of contiguous 1-bits followed by a block of 0-bits (i.e. 255.255.255.0), but it does not check.

/* 255.255.0.1 is 11111111.11111111.00000000.00000001 in  binary */
SubnetUtils su = new SubnetUtils("192.168.0.1", "255.255.0.1"); // expect error
SubnetInfo si = su.getInfo();
System.out.println(si.getNetmask()); // Expect error or 255.255.0.1
255.255.128.0

https://github.com/apache/commons-net/pull/13