Class ProtectedString

java.lang.Object
com.ibm.websphere.ras.ProtectedString
All Implemented Interfaces:
Traceable, FFDCSelfIntrospectable

public final class ProtectedString extends Object implements Traceable, FFDCSelfIntrospectable
The ProtectedString class wraps a String to protect sensitive strings from accidentally being printed in trace, FFDC, or via toString(). Instances of this class are immutable.

This class does not provide a constructor that takes a String, and it does not have a method to convert the contents to a String. This is deliberate to encourage the caller to never store passwords in a String, which might be accidentally logged in trace or FFDC. In particular, callers must avoid storing a String even indirectly, such as in a Map. Additionally, callers must be careful to avoid accidentally logging in trace or FFDC the char[] used to construct the instance or that is returned from getChars().

This implementation does not protect against the string being visible in clear text in JVM memory dumps. This class does not provide additional protection against the string being accessible via reflection, so callers should be careful to use private accessibility.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final ProtectedString
    A password object that holds the equivalent of the empty string
    static final ProtectedString
    A password object that holds null
  • Constructor Summary

    Constructors
    Constructor
    Description
    ProtectedString(char[] password)
    Construct a ProtectedString (typically a password) from an array of characters.
  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    Determine if this password is the same as another object NOTE: As with all equals() methods, this implementation obeys the requirements of java.lang.Object.equals().
    char[]
    Return the protected password (Note: it is then the job of the caller to prevent its copies reaching trace, ffdc or converting it to a string
    int
    return a hash code for this Password
    Provide details on the state of this object to ffdc, hiding the actual contents of the password
    boolean
    Return true if password is either null or has no characters (use in situations where some kind of password is required)
    Convert the password to a string, revealing only if it is null or non-null.
    Convert the password to a string for tracing purposes.

    Methods inherited from class java.lang.Object

    getClass, notify, notifyAll, wait, wait, wait
  • Field Details

    • NULL_PROTECTED_STRING

      public static final ProtectedString NULL_PROTECTED_STRING
      A password object that holds null
    • EMPTY_PROTECTED_STRING

      public static final ProtectedString EMPTY_PROTECTED_STRING
      A password object that holds the equivalent of the empty string
  • Constructor Details

    • ProtectedString

      public ProtectedString(char[] password)
      Construct a ProtectedString (typically a password) from an array of characters. The characters will not be revealed to trace or ffdc by this class
      Parameters:
      chars - The password to be protected
  • Method Details

    • getChars

      public char[] getChars()
      Return the protected password (Note: it is then the job of the caller to prevent its copies reaching trace, ffdc or converting it to a string
      Returns:
      char[] The protected password
    • toString

      public String toString()
      Convert the password to a string, revealing only if it is null or non-null. In particular note that it is NOT the password.
      Overrides:
      toString in class Object
      Returns:
      String A string representation of the password that can be used in trace etc.
    • toTraceString

      public String toTraceString()
      Convert the password to a string for tracing purposes. This provides a string that, for the same password, will be the same string, but will be different for different password (well, almost certainly different) and/or different class loaders (of Password). The password cannot be deduced from the trace string
      Specified by:
      toTraceString in interface Traceable
      Returns:
      String A string for the password for trace purposes
    • introspectSelf

      public String[] introspectSelf()
      Provide details on the state of this object to ffdc, hiding the actual contents of the password
      Specified by:
      introspectSelf in interface FFDCSelfIntrospectable
      Returns:
      String[] An array of strings to be added to the ffdc log
    • equals

      public boolean equals(Object o)
      Determine if this password is the same as another object NOTE: As with all equals() methods, this implementation obeys the requirements of java.lang.Object.equals(). In particular that requires that if a.equals(b), then b.equals(a). That means that we only check against other ProtectedString objects. If we returned true for any String that was passed in, we would then need to modify java.lang.String's implementation so that it returned true when passed in the correct ProtectedString....
      Overrides:
      equals in class Object
      Parameters:
      o - The other object
      Returns:
      boolean true if the other object is a Password and is the same of this one
    • hashCode

      public int hashCode()
      return a hash code for this Password
      Overrides:
      hashCode in class Object
      Returns:
      int The hash code of this password
    • isEmpty

      public boolean isEmpty()
      Return true if password is either null or has no characters (use in situations where some kind of password is required)
      Returns:
      true if password is null or has no characters.