[DIRMINA-1008] fromHexString converts non-hex Strings to ByteBuffer

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Invalid
• Component/s: Core
• Sprint: Mina Sprint 2.2.0
• Assignee: Jonathan Valliere
• Reporter: nullpointer
• Created: 16/Mar/15 20:07
• Updated: 15/Apr/20 14:50
• Resolved: 15/Apr/20 14:50

Description

I came across this by accident in class org.apache.mina.util.ByteBufferDumper:
fromHexString happily converts Strings like "ff, fa, f2" and "not a hex string" to bytes.

Here is a suggestion for curing the problem:

  public static ByteBuffer fromHexString(final String hex) {
    if (null == hex) {
      throw new IllegalArgumentException(
              "null argument not permitted");
    } else if (hex.length() % 2 != 0) {
      throw new IllegalArgumentException(
              "the hexadecimal string length cannot be odd");
    }
    int size = hex.length() / 2;
    ByteBuffer res = ByteBuffer.allocate(size);

    for (int i = 0; i < hex.length(); i += 2) {
      int b = Integer.parseInt(hex.substring(i, i + 2), 16);
      if (Integer.highestOneBit(b) == 128) {
        b = b - 256;
      }
      res.put((byte) b);
    }

    res.flip();
    return res;
 }