# Print output for @column tags ?> AttributionSource - Android SDK | Android Developers

Most visited

Recently visited

AttributionSource

public final class AttributionSource
extends Object implements Parcelable

java.lang.Object
   ↳ android.content.AttributionSource


This class represents a source to which access to permission protected data should be attributed. Attribution sources can be chained to represent cases where the protected data would flow through several applications. For example, app A may ask app B for contacts and in turn app B may ask app C for contacts. In this case, the attribution chain would be A -> B -> C and the data flow would be C -> B -> A. There are two main benefits of using the attribution source mechanism: avoid doing explicit permission checks on behalf of the calling app if you are accessing private data on their behalf to send back; avoid double data access blaming which happens as you check the calling app's permissions and when you access the data behind these permissions (for runtime permissions). Also if not explicitly blaming the caller the data access would be counted towards your app vs to the previous app where yours was just a proxy.

Every Context has an attribution source and you can get it via Context.getAttributionSource() representing itself, which is a chain of one. You can attribute work to another app, or more precisely to a chain of apps, through which the data you would be accessing would flow, via Context#createContext( ContextParams) plus specifying an attribution source for the next app to receive the protected data you are accessing via AttributionSource.Builder#setNext( AttributionSource). Creating this attribution chain ensures that the datasource would check whether every app in the attribution chain has permission to access the data before releasing it. The datasource will also record appropriately that this data was accessed by the apps in the sequence if the data is behind a sensitive permission (e.g. dangerous). Again, this is useful if you are accessing the data on behalf of another app, for example a speech recognizer using the mic so it can provide recognition to a calling app.

You can create an attribution chain of you and any other app without any verification as this is something already available via the AppOpsManager APIs. This is supported to handle cases where you don't have access to the caller's attribution source and you can directly use the AttributionSource.Builder APIs. However, if the data flows through more than two apps (more than you access the data for the caller) you need to have a handle to the AttributionSource for the calling app's context in order to create an attribution context. This means you either need to have an API for the other app to send you its attribution source or use a platform API that pipes the callers attribution source.

You cannot forge an attribution chain without the participation of every app in the attribution chain (aside of the special case mentioned above). To create an attribution source that is trusted you need to create an attribution context that points to an attribution source that was explicitly created by the app that it refers to, recursively.

Since creating an attribution context leads to all permissions for apps in the attribution chain being checked, you need to expect getting a security exception when accessing permission protected APIs since some app in the chain may not have the permission.

Summary

Nested classes

class AttributionSource.Builder

A builder for AttributionSource 

Inherited constants

Fields

public static final Creator<AttributionSource> CREATOR

Public methods

boolean checkCallingUid()

If you are handling an IPC and you don't trust the caller you need to validate whether the attribution source is one for the calling app to prevent the caller to pass you a source from another app without including themselves in the attribution chain.

int describeContents()

Describe the kinds of special objects contained in this Parcelable instance's marshaled representation.

void enforceCallingUid()

If you are handling an IPC and you don't trust the caller you need to validate whether the attribution source is one for the calling app to prevent the caller to pass you a source from another app without including themselves in the attribution chain.

boolean equals(Object o)

Indicates whether some other object is "equal to" this one.

String getAttributionTag()

The attribution tag of the app accessing the permission protected data.

AttributionSource getNext()

The next app to receive the permission protected data.

String getPackageName()

The package that is accessing the permission protected data.

int getUid()

The UID that is accessing the permission protected data.

int hashCode()

Returns a hash code value for the object.

boolean isTrusted(Context context)

Checks whether this attribution source can be trusted.

String toString()

Returns a string representation of the object.

void writeToParcel(Parcel dest, int flags)

Flatten this object in to a Parcel.

Inherited methods

Fields

CREATOR

public static final Creator<AttributionSource> CREATOR

Public methods

checkCallingUid

public boolean checkCallingUid ()

If you are handling an IPC and you don't trust the caller you need to validate whether the attribution source is one for the calling app to prevent the caller to pass you a source from another app without including themselves in the attribution chain. f

Returns
boolean if the attribution source cannot be trusted to be from the caller.

describeContents

public int describeContents ()

Describe the kinds of special objects contained in this Parcelable instance's marshaled representation. For example, if the object will include a file descriptor in the output of writeToParcel(android.os.Parcel, int), the return value of this method must include the CONTENTS_FILE_DESCRIPTOR bit.

Returns
int a bitmask indicating the set of special object types marshaled by this Parcelable object instance. Value is either 0 or CONTENTS_FILE_DESCRIPTOR

enforceCallingUid

public void enforceCallingUid ()

If you are handling an IPC and you don't trust the caller you need to validate whether the attribution source is one for the calling app to prevent the caller to pass you a source from another app without including themselves in the attribution chain.

Throws
SecurityException if the attribution source cannot be trusted to be from the caller.

equals

public boolean equals (Object o)

Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

  • It is reflexive: for any non-null reference value x, x.equals(x) should return true.
  • It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
  • It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
  • It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
  • For any non-null reference value x, x.equals(null) should return false.

The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values x and y, this method returns true if and only if x and y refer to the same object (x == y has the value true).

Note that it is generally necessary to override the hashCode method whenever this method is overridden, so as to maintain the general contract for the hashCode method, which states that equal objects must have equal hash codes.

Parameters
o Object: This value may be null.

Returns
boolean true if this object is the same as the obj argument; false otherwise.

getAttributionTag

public String getAttributionTag ()

The attribution tag of the app accessing the permission protected data.

Returns
String This value may be null.

getNext

public AttributionSource getNext ()

The next app to receive the permission protected data.

Returns
AttributionSource This value may be null.

getPackageName

public String getPackageName ()

The package that is accessing the permission protected data.

Returns
String This value may be null.

getUid

public int getUid ()

The UID that is accessing the permission protected data.

Returns
int

hashCode

public int hashCode ()

Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by HashMap.

The general contract of hashCode is:

  • Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
  • If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result.
  • It is not required that if two objects are unequal according to the equals(java.lang.Object) method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.

As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the Java™ programming language.)

Returns
int a hash code value for this object.

isTrusted

public boolean isTrusted (Context context)

Checks whether this attribution source can be trusted. That is whether the app it refers to created it and provided to the attribution chain.

Parameters
context Context: Context handle. This value cannot be null.

Returns
boolean Whether this is a trusted source.

toString

public String toString ()

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())
 

Returns
String a string representation of the object.

writeToParcel

public void writeToParcel (Parcel dest, 
                int flags)

Flatten this object in to a Parcel.

Parameters
dest Parcel: This value cannot be null.

flags int: Additional flags about how the object should be written. May be 0 or Parcelable.PARCELABLE_WRITE_RETURN_VALUE. Value is either 0 or a combination of Parcelable.PARCELABLE_WRITE_RETURN_VALUE, and android.os.Parcelable.PARCELABLE_ELIDE_DUPLICATES