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Commit a1111ffe authored by Nikita Ioffe's avatar Nikita Ioffe
Browse files

Allow RollbackManager to downgrade apks on user builds 

- If running on a debug build, same behaviour is preserved.
- In case of a user build, INSTALL_ALLOW_DOWNGRADE flag is respected
  only if it's system_server who commits the session.

Test: atest RollbackTest on user build
Test: manually tried to downgrade apk on a user build, it failed.
Bug: 125657835
Change-Id: I469f6513831cc727fc7e62ce1ff4f6ef472ab5e9
parent c20b41f5

core/java/android/content/pm/PackageInstaller.java

+1 −0
Original line number Diff line number Diff line
@@ -1343,6 +1343,7 @@ public class PackageInstaller { 
         */

        public boolean areHiddenOptionsSet() {

            return (installFlags & (PackageManager.INSTALL_ALLOW_DOWNGRADE

                    | PackageManager.INSTALL_RESPECT_ALLOW_DOWNGRADE

                    | PackageManager.INSTALL_DONT_KILL_APP

                    | PackageManager.INSTALL_INSTANT_APP

                    | PackageManager.INSTALL_FULL_APP

core/java/android/content/pm/PackageManager.java

+10 −0
Original line number Diff line number Diff line
@@ -721,6 +721,7 @@ public abstract class PackageManager { 
            INSTALL_VIRTUAL_PRELOAD,

            INSTALL_APEX,

            INSTALL_ENABLE_ROLLBACK,

            INSTALL_RESPECT_ALLOW_DOWNGRADE,

    })

    @Retention(RetentionPolicy.SOURCE)

    public @interface InstallFlags {}
@@ -865,6 +866,15 @@ public abstract class PackageManager { 
     */

    public static final int INSTALL_DISABLE_VERIFICATION = 0x00080000;



    /**

     * Flag parameter for {@link #installPackage} to indicate that

     * {@link #INSTALL_ALLOW_DOWNGRADE} should be respected.

     *

     * @hide

     */

    // TODO(b/127322579): rename

    public static final int INSTALL_RESPECT_ALLOW_DOWNGRADE = 0x00100000;



    /** @hide */

    @IntDef(flag = true, prefix = { "DONT_KILL_APP" }, value = {

            DONT_KILL_APP

services/core/java/com/android/server/pm/PackageInstallerService.java

+6 −0
Original line number Diff line number Diff line
@@ -481,6 +481,12 @@ public class PackageInstallerService extends IPackageInstaller.Stub implements 
            }

        }



        if (callingUid == Process.SYSTEM_UID) {

            params.installFlags |= PackageManager.INSTALL_RESPECT_ALLOW_DOWNGRADE;

        } else {

            params.installFlags &= ~PackageManager.INSTALL_RESPECT_ALLOW_DOWNGRADE;

        }



        boolean isApex = (params.installFlags & PackageManager.INSTALL_APEX) != 0;

        if (params.isStaged || isApex) {

            mContext.enforceCallingOrSelfPermission(Manifest.permission.INSTALL_PACKAGES, TAG);

services/core/java/com/android/server/pm/PackageManagerServiceUtils.java

+14 −5
Original line number Diff line number Diff line
@@ -806,7 +806,7 @@ public class PackageManagerServiceUtils { 
     */

    public static boolean isDowngradePermitted(int installFlags, int applicationFlags) {

        // If installed, the package will get access to data left on the device by its

        // predecessor. As a security measure, this is permited only if this is not a

        // predecessor. As a security measure, this is permitted only if this is not a

        // version downgrade or if the predecessor package is marked as debuggable and

        // a downgrade is explicitly requested.

        //
@@ -818,12 +818,21 @@ public class PackageManagerServiceUtils { 
        // installFlags. This is because we aim to keep the behavior of debuggable

        // platform builds as close as possible to the behavior of non-debuggable

        // platform builds.

        //

        // In case of user builds, downgrade is permitted only for the system server initiated

        // sessions. This is enforced by INSTALL_RESPECT_ALLOW_DOWNGRADE flag parameter.

        final boolean downgradeRequested =

                (installFlags & PackageManager.INSTALL_ALLOW_DOWNGRADE) != 0;

        final boolean packageDebuggable =

                (applicationFlags

                        & ApplicationInfo.FLAG_DEBUGGABLE) != 0;

        return (downgradeRequested) && ((Build.IS_DEBUGGABLE) || (packageDebuggable));

        if (!downgradeRequested) {

            return false;

        }

        final boolean isDebuggable =

                Build.IS_DEBUGGABLE || ((applicationFlags

                        & ApplicationInfo.FLAG_DEBUGGABLE) != 0);

        if (isDebuggable) {

            return true;

        }

        return (installFlags & PackageManager.INSTALL_RESPECT_ALLOW_DOWNGRADE) != 0;

    }



    /**