diff --git a/core/tests/coretests/AndroidManifest.xml b/core/tests/coretests/AndroidManifest.xml
index eb005ce407774..9972a8c22e31e 100644
--- a/core/tests/coretests/AndroidManifest.xml
+++ b/core/tests/coretests/AndroidManifest.xml
@@ -15,6 +15,7 @@
 -->
 
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
+          android:installLocation="internalOnly"
           package="com.android.frameworks.coretests">
 
     <permission android:name="com.android.frameworks.coretests.permission.TEST_GRANTED"
diff --git a/core/tests/coretests/res/raw/install_app1_cert1 b/core/tests/coretests/res/raw/install_app1_cert1
new file mode 100644
index 0000000000000..67eb2de645d37
Binary files /dev/null and b/core/tests/coretests/res/raw/install_app1_cert1 differ
diff --git a/core/tests/coretests/res/raw/install_app1_cert1_cert2 b/core/tests/coretests/res/raw/install_app1_cert1_cert2
new file mode 100644
index 0000000000000..dbafdc509181a
Binary files /dev/null and b/core/tests/coretests/res/raw/install_app1_cert1_cert2 differ
diff --git a/core/tests/coretests/res/raw/install_app1_cert2 b/core/tests/coretests/res/raw/install_app1_cert2
new file mode 100644
index 0000000000000..e26c2eb20f8db
Binary files /dev/null and b/core/tests/coretests/res/raw/install_app1_cert2 differ
diff --git a/core/tests/coretests/res/raw/install_app1_cert3 b/core/tests/coretests/res/raw/install_app1_cert3
new file mode 100644
index 0000000000000..fa10be760022a
Binary files /dev/null and b/core/tests/coretests/res/raw/install_app1_cert3 differ
diff --git a/core/tests/coretests/res/raw/install_app1_cert3_cert4 b/core/tests/coretests/res/raw/install_app1_cert3_cert4
new file mode 100644
index 0000000000000..c2f6c81a63072
Binary files /dev/null and b/core/tests/coretests/res/raw/install_app1_cert3_cert4 differ
diff --git a/core/tests/coretests/res/raw/install_app1_unsigned b/core/tests/coretests/res/raw/install_app1_unsigned
new file mode 100644
index 0000000000000..18be5f856bfcb
Binary files /dev/null and b/core/tests/coretests/res/raw/install_app1_unsigned differ
diff --git a/core/tests/coretests/res/raw/install_app2_cert1 b/core/tests/coretests/res/raw/install_app2_cert1
new file mode 100644
index 0000000000000..b34573202f661
Binary files /dev/null and b/core/tests/coretests/res/raw/install_app2_cert1 differ
diff --git a/core/tests/coretests/res/raw/install_app2_cert1_cert2 b/core/tests/coretests/res/raw/install_app2_cert1_cert2
new file mode 100644
index 0000000000000..1faa257b451aa
Binary files /dev/null and b/core/tests/coretests/res/raw/install_app2_cert1_cert2 differ
diff --git a/core/tests/coretests/res/raw/install_app2_cert2 b/core/tests/coretests/res/raw/install_app2_cert2
new file mode 100644
index 0000000000000..c3d597904a8cc
Binary files /dev/null and b/core/tests/coretests/res/raw/install_app2_cert2 differ
diff --git a/core/tests/coretests/res/raw/install_app2_cert3 b/core/tests/coretests/res/raw/install_app2_cert3
new file mode 100644
index 0000000000000..ac0d9da2067da
Binary files /dev/null and b/core/tests/coretests/res/raw/install_app2_cert3 differ
diff --git a/core/tests/coretests/res/raw/install_app2_unsigned b/core/tests/coretests/res/raw/install_app2_unsigned
new file mode 100644
index 0000000000000..8d24e888127cf
Binary files /dev/null and b/core/tests/coretests/res/raw/install_app2_unsigned differ
diff --git a/core/tests/coretests/res/raw/install_shared1_cert1 b/core/tests/coretests/res/raw/install_shared1_cert1
new file mode 100644
index 0000000000000..d702dabbb6766
Binary files /dev/null and b/core/tests/coretests/res/raw/install_shared1_cert1 differ
diff --git a/core/tests/coretests/res/raw/install_shared1_cert12 b/core/tests/coretests/res/raw/install_shared1_cert12
new file mode 100644
index 0000000000000..b580b60a5feef
Binary files /dev/null and b/core/tests/coretests/res/raw/install_shared1_cert12 differ
diff --git a/core/tests/coretests/res/raw/install_shared1_cert1_cert2 b/core/tests/coretests/res/raw/install_shared1_cert1_cert2
new file mode 100644
index 0000000000000..b580b60a5feef
Binary files /dev/null and b/core/tests/coretests/res/raw/install_shared1_cert1_cert2 differ
diff --git a/core/tests/coretests/res/raw/install_shared1_cert2 b/core/tests/coretests/res/raw/install_shared1_cert2
new file mode 100644
index 0000000000000..a2de801249ad7
Binary files /dev/null and b/core/tests/coretests/res/raw/install_shared1_cert2 differ
diff --git a/core/tests/coretests/res/raw/install_shared1_unsigned b/core/tests/coretests/res/raw/install_shared1_unsigned
new file mode 100644
index 0000000000000..35680be1697e1
Binary files /dev/null and b/core/tests/coretests/res/raw/install_shared1_unsigned differ
diff --git a/core/tests/coretests/res/raw/install_shared2_cert1 b/core/tests/coretests/res/raw/install_shared2_cert1
new file mode 100644
index 0000000000000..9064de7840b08
Binary files /dev/null and b/core/tests/coretests/res/raw/install_shared2_cert1 differ
diff --git a/core/tests/coretests/res/raw/install_shared2_cert12 b/core/tests/coretests/res/raw/install_shared2_cert12
new file mode 100644
index 0000000000000..26a250d5d7f03
Binary files /dev/null and b/core/tests/coretests/res/raw/install_shared2_cert12 differ
diff --git a/core/tests/coretests/res/raw/install_shared2_cert1_cert2 b/core/tests/coretests/res/raw/install_shared2_cert1_cert2
new file mode 100644
index 0000000000000..26a250d5d7f03
Binary files /dev/null and b/core/tests/coretests/res/raw/install_shared2_cert1_cert2 differ
diff --git a/core/tests/coretests/res/raw/install_shared2_cert2 b/core/tests/coretests/res/raw/install_shared2_cert2
new file mode 100644
index 0000000000000..79813087c142f
Binary files /dev/null and b/core/tests/coretests/res/raw/install_shared2_cert2 differ
diff --git a/core/tests/coretests/res/raw/install_shared2_unsigned b/core/tests/coretests/res/raw/install_shared2_unsigned
new file mode 100644
index 0000000000000..ad909fd6c9d0a
Binary files /dev/null and b/core/tests/coretests/res/raw/install_shared2_unsigned differ
diff --git a/core/tests/coretests/src/android/content/pm/PackageManagerTests.java b/core/tests/coretests/src/android/content/pm/PackageManagerTests.java
index 7b9e95a161d4c..aec82afed58d2 100755
--- a/core/tests/coretests/src/android/content/pm/PackageManagerTests.java
+++ b/core/tests/coretests/src/android/content/pm/PackageManagerTests.java
@@ -23,10 +23,18 @@ import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
+import android.content.pm.ApplicationInfo;
+import android.content.pm.PackageInfo;
+import android.content.pm.PackageManager;
+import android.content.pm.PackageParser;
 import android.content.pm.PackageManager.NameNotFoundException;
 import android.content.res.Resources;
 import android.content.res.Resources.NotFoundException;
 import android.net.Uri;
+import android.test.AndroidTestCase;
+import android.test.suitebuilder.annotation.Suppress;
+import android.util.DisplayMetrics;
+import android.util.Log;
 import android.os.Environment;
 import android.os.FileUtils;
 import android.os.IBinder;
@@ -497,6 +505,15 @@ public class PackageManagerTests extends AndroidTestCase {
         }
     }
 
+    private PackageParser.Package getParsedPackage(String outFileName, int rawResId) {
+        PackageManager pm = mContext.getPackageManager();
+        File filesDir = mContext.getFilesDir();
+        File outFile = new File(filesDir, outFileName);
+        Uri packageURI = getInstallablePackage(rawResId, outFile);
+        PackageParser.Package pkg = parsePackage(packageURI);
+        return pkg;
+    }
+
     /*
      * Utility function that reads a apk bundled as a raw resource
      * copies it into own data directory and invokes
@@ -529,7 +546,9 @@ public class PackageManagerTests extends AndroidTestCase {
             if (fail) {
                 assertTrue(invokeInstallPackageFail(packageURI, flags,
                         pkg.packageName, result));
-                assertNotInstalled(pkg.packageName);
+                if ((flags & PackageManager.INSTALL_REPLACE_EXISTING) == 0) {
+                    assertNotInstalled(pkg.packageName);
+                }
             } else {
                 InstallReceiver receiver = new InstallReceiver(pkg.packageName);
                 assertTrue(invokeInstallPackage(packageURI, flags,
@@ -621,7 +640,7 @@ public class PackageManagerTests extends AndroidTestCase {
      * PackageManager api to install first and then replace it
      * again.
      */
-    public void replaceFromRawResource(int flags) {
+    private void sampleReplaceFromRawResource(int flags) {
         InstallParams ip = sampleInstallFromRawResource(flags, false);
         boolean replace = ((flags & PackageManager.INSTALL_REPLACE_EXISTING) != 0);
         Log.i(TAG, "replace=" + replace);
@@ -648,28 +667,28 @@ public class PackageManagerTests extends AndroidTestCase {
     }
 
     public void testReplaceFailNormalInternal() {
-        replaceFromRawResource(0);
+        sampleReplaceFromRawResource(0);
     }
 
     public void testReplaceFailFwdLockedInternal() {
-        replaceFromRawResource(PackageManager.INSTALL_FORWARD_LOCK);
+        sampleReplaceFromRawResource(PackageManager.INSTALL_FORWARD_LOCK);
     }
 
     public void testReplaceFailSdcard() {
-        replaceFromRawResource(PackageManager.INSTALL_EXTERNAL);
+        sampleReplaceFromRawResource(PackageManager.INSTALL_EXTERNAL);
     }
 
     public void testReplaceNormalInternal() {
-        replaceFromRawResource(PackageManager.INSTALL_REPLACE_EXISTING);
+        sampleReplaceFromRawResource(PackageManager.INSTALL_REPLACE_EXISTING);
     }
 
     public void testReplaceFwdLockedInternal() {
-        replaceFromRawResource(PackageManager.INSTALL_REPLACE_EXISTING |
+        sampleReplaceFromRawResource(PackageManager.INSTALL_REPLACE_EXISTING |
                 PackageManager.INSTALL_FORWARD_LOCK);
     }
 
     public void testReplaceSdcard() {
-        replaceFromRawResource(PackageManager.INSTALL_REPLACE_EXISTING |
+        sampleReplaceFromRawResource(PackageManager.INSTALL_REPLACE_EXISTING |
                 PackageManager.INSTALL_EXTERNAL);
     }
 
@@ -1014,6 +1033,19 @@ public class PackageManagerTests extends AndroidTestCase {
             outFile.delete();
         }
     }
+    void cleanUpInstall(String pkgName) {
+        if (pkgName == null) {
+            return;
+        }
+        Log.i(TAG, "Deleting package : " + pkgName);
+        try {
+            ApplicationInfo info = getPm().getApplicationInfo(pkgName,
+                    PackageManager.GET_UNINSTALLED_PACKAGES);
+            if (info != null) {
+                getPm().deletePackage(pkgName, null, 0);
+            }
+        } catch (NameNotFoundException e) {}
+    }
 
     public void testManifestInstallLocationInternal() {
         installFromRawResource("install.apk", R.raw.install_loc_internal,
@@ -2152,6 +2184,360 @@ public class PackageManagerTests extends AndroidTestCase {
 
         }
     }
+    /*
+     * The following series of tests are related to upgrading apps with
+     * different certificates. 
+     */
+    private int APP1_UNSIGNED = R.raw.install_app1_unsigned;
+    private int APP1_CERT1 = R.raw.install_app1_cert1;
+    private int APP1_CERT2 = R.raw.install_app1_cert2;
+    private int APP1_CERT1_CERT2 = R.raw.install_app1_cert1_cert2;
+    private int APP1_CERT3_CERT4 = R.raw.install_app1_cert3_cert4;
+    private int APP1_CERT3 = R.raw.install_app1_cert3;
+    private int APP2_UNSIGNED = R.raw.install_app2_unsigned;
+    private int APP2_CERT1 = R.raw.install_app2_cert1;
+    private int APP2_CERT2 = R.raw.install_app2_cert2;
+    private int APP2_CERT1_CERT2 = R.raw.install_app2_cert1_cert2;
+    private int APP2_CERT3 = R.raw.install_app2_cert3;
+
+    private InstallParams replaceCerts(int apk1, int apk2, boolean cleanUp, boolean fail, int retCode) {
+        int rFlags = PackageManager.INSTALL_REPLACE_EXISTING;
+        String apk1Name = "install1.apk";
+        String apk2Name = "install2.apk";
+        PackageParser.Package pkg1 = getParsedPackage(apk1Name, apk1);
+        try {
+            InstallParams ip = installFromRawResource(apk1Name, apk1, 0, false,
+                    false, -1, PackageInfo.INSTALL_LOCATION_UNSPECIFIED);
+            installFromRawResource(apk2Name, apk2, rFlags, false,
+                    fail, retCode, PackageInfo.INSTALL_LOCATION_UNSPECIFIED);
+            return ip;
+        } catch (Exception e) {
+            failStr(e.getMessage());
+        } finally {
+            if (cleanUp) {
+                cleanUpInstall(pkg1.packageName);
+            }
+        }
+        return null;
+    }
+    /*
+     * Test that an app signed with two certificates can be upgraded by the
+     * same app signed with two certificates.
+     */
+    public void testReplaceMatchAllCerts() {
+        replaceCerts(APP1_CERT1_CERT2, APP1_CERT1_CERT2, true, false, -1);
+    }
+
+    /*
+     * Test that an app signed with two certificates cannot be upgraded
+     * by an app signed with a different certificate.
+     */
+    public void testReplaceMatchNoCerts1() {
+        replaceCerts(APP1_CERT1_CERT2, APP1_CERT3, true, true,
+                PackageManager.INSTALL_PARSE_FAILED_INCONSISTENT_CERTIFICATES);
+    }
+    /*
+     * Test that an app signed with two certificates cannot be upgraded
+     * by an app signed with a different certificate.
+     */
+    public void testReplaceMatchNoCerts2() {
+        replaceCerts(APP1_CERT1_CERT2, APP1_CERT3_CERT4, true, true,
+                PackageManager.INSTALL_PARSE_FAILED_INCONSISTENT_CERTIFICATES);
+    }
+    /*
+     * Test that an app signed with two certificates cannot be upgraded by
+     * an app signed with a subset of initial certificates.
+     */
+    public void testReplaceMatchSomeCerts1() {
+        replaceCerts(APP1_CERT1_CERT2, APP1_CERT1, true, true,
+                PackageManager.INSTALL_PARSE_FAILED_INCONSISTENT_CERTIFICATES);
+    }
+    /*
+     * Test that an app signed with two certificates cannot be upgraded by
+     * an app signed with the last certificate.
+     */
+    public void testReplaceMatchSomeCerts2() {
+        replaceCerts(APP1_CERT1_CERT2, APP1_CERT2, true, true,
+                PackageManager.INSTALL_PARSE_FAILED_INCONSISTENT_CERTIFICATES);
+    }
+    /*
+     * Test that an app signed with a certificate can be upgraded by app
+     * signed with a superset of certificates.
+     */
+    public void testReplaceMatchMoreCerts() {
+        replaceCerts(APP1_CERT1, APP1_CERT1_CERT2, true, true,
+                PackageManager.INSTALL_PARSE_FAILED_INCONSISTENT_CERTIFICATES);
+    }
+    /*
+     * Test that an app signed with a certificate can be upgraded by app
+     * signed with a superset of certificates. Then verify that the an app
+     * signed with the original set of certs cannot upgrade the new one.
+     */
+    public void testReplaceMatchMoreCertsReplaceSomeCerts() {
+        InstallParams ip = replaceCerts(APP1_CERT1, APP1_CERT1_CERT2, false, true,
+                PackageManager.INSTALL_PARSE_FAILED_INCONSISTENT_CERTIFICATES);
+        try {
+            int rFlags = PackageManager.INSTALL_REPLACE_EXISTING;
+            installFromRawResource("install.apk", APP1_CERT1, rFlags, false,
+                    false, -1,
+                    PackageInfo.INSTALL_LOCATION_UNSPECIFIED);
+        } catch (Exception e) {
+            failStr(e.getMessage());
+        } finally {
+            if (ip != null) {
+                cleanUpInstall(ip);
+            }
+        }
+    }
+    /*
+     * The following tests are related to testing the checkSignatures
+     * api.
+     */
+    private void checkSignatures(int apk1, int apk2, int expMatchResult) {
+        checkSharedSignatures(apk1, apk2, true, false, -1, expMatchResult);
+    }
+    public void testCheckSignaturesAllMatch() {
+        int apk1 = APP1_CERT1_CERT2;
+        int apk2 = APP2_CERT1_CERT2;
+        checkSignatures(apk1, apk2, PackageManager.SIGNATURE_MATCH);
+    }
+    public void testCheckSignaturesNoMatch() {
+        int apk1 = APP1_CERT1;
+        int apk2 = APP2_CERT2;
+        checkSignatures(apk1, apk2, PackageManager.SIGNATURE_NO_MATCH);
+    }
+    public void testCheckSignaturesSomeMatch1() {
+        int apk1 = APP1_CERT1_CERT2;
+        int apk2 = APP2_CERT1;
+        checkSignatures(apk1, apk2, PackageManager.SIGNATURE_NO_MATCH);
+    }
+    public void testCheckSignaturesSomeMatch2() {
+        int apk1 = APP1_CERT1_CERT2;
+        int apk2 = APP2_CERT2;
+        checkSignatures(apk1, apk2, PackageManager.SIGNATURE_NO_MATCH);
+    }
+    public void testCheckSignaturesMoreMatch() {
+        int apk1 = APP1_CERT1;
+        int apk2 = APP2_CERT1_CERT2;
+        checkSignatures(apk1, apk2, PackageManager.SIGNATURE_NO_MATCH);
+    }
+    public void testCheckSignaturesUnknown() {
+        int apk1 = APP1_CERT1_CERT2;
+        int apk2 = APP2_CERT1_CERT2;
+        String apk1Name = "install1.apk";
+        String apk2Name = "install2.apk";
+        InstallParams ip1 = null;
+
+        try {
+            ip1 = installFromRawResource(apk1Name, apk1, 0, false,
+                    false, -1, PackageInfo.INSTALL_LOCATION_UNSPECIFIED);
+            PackageManager pm = mContext.getPackageManager();
+            // Delete app2
+            File filesDir = mContext.getFilesDir();
+            File outFile = new File(filesDir, apk2Name);
+            int rawResId = apk2;
+            Uri packageURI = getInstallablePackage(rawResId, outFile);
+            PackageParser.Package pkg = parsePackage(packageURI);
+            getPm().deletePackage(pkg.packageName, null, 0);
+            // Check signatures now
+            int match = mContext.getPackageManager().checkSignatures(
+                    ip1.pkg.packageName, pkg.packageName);
+            assertEquals(PackageManager.SIGNATURE_UNKNOWN_PACKAGE, match);
+        } finally {
+            if (ip1 != null) {
+                cleanUpInstall(ip1);
+            }
+        }
+    }
+    public void testInstallNoCertificates() {
+        int apk1 = APP1_UNSIGNED;
+        String apk1Name = "install1.apk";
+        InstallParams ip1 = null;
+
+        try {
+            installFromRawResource(apk1Name, apk1, 0, false,
+                    true, PackageManager.INSTALL_PARSE_FAILED_NO_CERTIFICATES,
+                    PackageInfo.INSTALL_LOCATION_UNSPECIFIED);
+        } finally {
+        }
+    }
+    /* The following tests are related to apps using shared uids signed
+     * with different certs.
+     */
+    private int SHARED1_UNSIGNED = R.raw.install_shared1_unsigned;
+    private int SHARED1_CERT1 = R.raw.install_shared1_cert1;
+    private int SHARED1_CERT2 = R.raw.install_shared1_cert2;
+    private int SHARED1_CERT1_CERT2 = R.raw.install_shared1_cert1_cert2;
+    private int SHARED2_UNSIGNED = R.raw.install_shared2_unsigned;
+    private int SHARED2_CERT1 = R.raw.install_shared2_cert1;
+    private int SHARED2_CERT2 = R.raw.install_shared2_cert2;
+    private int SHARED2_CERT1_CERT2 = R.raw.install_shared2_cert1_cert2;
+    private void checkSharedSignatures(int apk1, int apk2, boolean cleanUp, boolean fail, int retCode, int expMatchResult) {
+        String apk1Name = "install1.apk";
+        String apk2Name = "install2.apk";
+        PackageParser.Package pkg1 = getParsedPackage(apk1Name, apk1);
+        PackageParser.Package pkg2 = getParsedPackage(apk2Name, apk2);
+
+        try {
+            // Clean up before testing first.
+            cleanUpInstall(pkg1.packageName);
+            cleanUpInstall(pkg2.packageName);
+            installFromRawResource(apk1Name, apk1, 0, false,
+                    false, -1, PackageInfo.INSTALL_LOCATION_UNSPECIFIED);
+            if (fail) {
+                installFromRawResource(apk2Name, apk2, 0, false,
+                        true, retCode, PackageInfo.INSTALL_LOCATION_UNSPECIFIED);
+            } else {
+                installFromRawResource(apk2Name, apk2, 0, false,
+                        false, -1, PackageInfo.INSTALL_LOCATION_UNSPECIFIED);
+                int match = mContext.getPackageManager().checkSignatures(
+                        pkg1.packageName, pkg2.packageName);
+                assertEquals(expMatchResult, match);
+            }
+        } finally {
+            if (cleanUp) {
+                cleanUpInstall(pkg1.packageName);
+                cleanUpInstall(pkg2.packageName);
+            }
+        }
+    }
+    public void testCheckSignaturesSharedAllMatch() {
+        int apk1 = SHARED1_CERT1_CERT2;
+        int apk2 = SHARED2_CERT1_CERT2;
+        boolean fail = false;
+        int retCode = -1;
+        int expMatchResult = PackageManager.SIGNATURE_MATCH;
+        checkSharedSignatures(apk1, apk2, true, fail, retCode, expMatchResult);
+    }
+    public void testCheckSignaturesSharedNoMatch() {
+        int apk1 = SHARED1_CERT1;
+        int apk2 = SHARED2_CERT2;
+        boolean fail = true;
+        int retCode = PackageManager.INSTALL_FAILED_SHARED_USER_INCOMPATIBLE;
+        int expMatchResult = -1;
+        checkSharedSignatures(apk1, apk2, true, fail, retCode, expMatchResult);
+    }
+    /*
+     * Test that an app signed with cert1 and cert2 cannot be replaced when signed with cert1 alone.
+     */
+    public void testCheckSignaturesSharedSomeMatch1() {
+        int apk1 = SHARED1_CERT1_CERT2;
+        int apk2 = SHARED2_CERT1;
+        boolean fail = true;
+        int retCode = PackageManager.INSTALL_FAILED_SHARED_USER_INCOMPATIBLE;
+        int expMatchResult = -1;
+        checkSharedSignatures(apk1, apk2, true, fail, retCode, expMatchResult);
+    }
+    /*
+     * Test that an app signed with cert1 and cert2 cannot be replaced when signed with cert2 alone.
+     */
+    public void testCheckSignaturesSharedSomeMatch2() {
+        int apk1 = SHARED1_CERT1_CERT2;
+        int apk2 = SHARED2_CERT2;
+        boolean fail = true;
+        int retCode = PackageManager.INSTALL_FAILED_SHARED_USER_INCOMPATIBLE;
+        int expMatchResult = -1;
+        checkSharedSignatures(apk1, apk2, true, fail, retCode, expMatchResult);
+    }
+    public void testCheckSignaturesSharedUnknown() {
+        int apk1 = SHARED1_CERT1_CERT2;
+        int apk2 = SHARED2_CERT1_CERT2;
+        String apk1Name = "install1.apk";
+        String apk2Name = "install2.apk";
+        InstallParams ip1 = null;
+
+        try {
+            ip1 = installFromRawResource(apk1Name, apk1, 0, false,
+                    false, -1, PackageInfo.INSTALL_LOCATION_UNSPECIFIED);
+            PackageManager pm = mContext.getPackageManager();
+            // Delete app2
+            PackageParser.Package pkg = getParsedPackage(apk2Name, apk2);
+            getPm().deletePackage(pkg.packageName, null, 0);
+            // Check signatures now
+            int match = mContext.getPackageManager().checkSignatures(
+                    ip1.pkg.packageName, pkg.packageName);
+            assertEquals(PackageManager.SIGNATURE_UNKNOWN_PACKAGE, match);
+        } finally {
+            if (ip1 != null) {
+                cleanUpInstall(ip1);
+            }
+        }
+    }
+    
+    public void testReplaceFirstSharedMatchAllCerts() {
+        int apk1 = SHARED1_CERT1;
+        int apk2 = SHARED2_CERT1;
+        int rapk1 = SHARED1_CERT1;
+        checkSignatures(apk1, apk2, PackageManager.SIGNATURE_MATCH);
+        replaceCerts(apk1, rapk1, true, false, -1);
+    }
+    public void testReplaceSecondSharedMatchAllCerts() {
+        int apk1 = SHARED1_CERT1;
+        int apk2 = SHARED2_CERT1;
+        int rapk2 = SHARED2_CERT1;
+        checkSignatures(apk1, apk2, PackageManager.SIGNATURE_MATCH);
+        replaceCerts(apk2, rapk2, true, false, -1);
+    }
+    public void testReplaceFirstSharedMatchSomeCerts() {
+        int apk1 = SHARED1_CERT1_CERT2;
+        int apk2 = SHARED2_CERT1_CERT2;
+        int rapk1 = SHARED1_CERT1;
+        boolean fail = true;
+        int retCode = PackageManager.INSTALL_PARSE_FAILED_INCONSISTENT_CERTIFICATES;
+        checkSharedSignatures(apk1, apk2, false, false, -1, PackageManager.SIGNATURE_MATCH);
+        installFromRawResource("install.apk", rapk1, PackageManager.INSTALL_REPLACE_EXISTING, true,
+                fail, retCode, PackageInfo.INSTALL_LOCATION_UNSPECIFIED);
+    }
+    public void testReplaceSecondSharedMatchSomeCerts() {
+        int apk1 = SHARED1_CERT1_CERT2;
+        int apk2 = SHARED2_CERT1_CERT2;
+        int rapk2 = SHARED2_CERT1;
+        boolean fail = true;
+        int retCode = PackageManager.INSTALL_PARSE_FAILED_INCONSISTENT_CERTIFICATES;
+        checkSharedSignatures(apk1, apk2, false, false, -1, PackageManager.SIGNATURE_MATCH);
+        installFromRawResource("install.apk", rapk2, PackageManager.INSTALL_REPLACE_EXISTING, true,
+                fail, retCode, PackageInfo.INSTALL_LOCATION_UNSPECIFIED);
+    }
+    public void testReplaceFirstSharedMatchNoCerts() {
+        int apk1 = SHARED1_CERT1;
+        int apk2 = SHARED2_CERT1;
+        int rapk1 = SHARED1_CERT2;
+        boolean fail = true;
+        int retCode = PackageManager.INSTALL_PARSE_FAILED_INCONSISTENT_CERTIFICATES;
+        checkSharedSignatures(apk1, apk2, false, false, -1, PackageManager.SIGNATURE_MATCH);
+        installFromRawResource("install.apk", rapk1, PackageManager.INSTALL_REPLACE_EXISTING, true,
+                fail, retCode, PackageInfo.INSTALL_LOCATION_UNSPECIFIED);
+    }
+    public void testReplaceSecondSharedMatchNoCerts() {
+        int apk1 = SHARED1_CERT1;
+        int apk2 = SHARED2_CERT1;
+        int rapk2 = SHARED2_CERT2;
+        boolean fail = true;
+        int retCode = PackageManager.INSTALL_PARSE_FAILED_INCONSISTENT_CERTIFICATES;
+        checkSharedSignatures(apk1, apk2, false, false, -1, PackageManager.SIGNATURE_MATCH);
+        installFromRawResource("install.apk", rapk2, PackageManager.INSTALL_REPLACE_EXISTING, true,
+                fail, retCode, PackageInfo.INSTALL_LOCATION_UNSPECIFIED);
+    }
+    public void testReplaceFirstSharedMatchMoreCerts() {
+        int apk1 = SHARED1_CERT1;
+        int apk2 = SHARED2_CERT1;
+        int rapk1 = SHARED1_CERT1_CERT2;
+        boolean fail = true;
+        int retCode = PackageManager.INSTALL_PARSE_FAILED_INCONSISTENT_CERTIFICATES;
+        checkSharedSignatures(apk1, apk2, false, false, -1, PackageManager.SIGNATURE_MATCH);
+        installFromRawResource("install.apk", rapk1, PackageManager.INSTALL_REPLACE_EXISTING, true,
+                fail, retCode, PackageInfo.INSTALL_LOCATION_UNSPECIFIED);
+    }
+    public void testReplaceSecondSharedMatchMoreCerts() {
+        int apk1 = SHARED1_CERT1;
+        int apk2 = SHARED2_CERT1;
+        int rapk2 = SHARED2_CERT1_CERT2;
+        boolean fail = true;
+        int retCode = PackageManager.INSTALL_PARSE_FAILED_INCONSISTENT_CERTIFICATES;
+        checkSharedSignatures(apk1, apk2, false, false, -1, PackageManager.SIGNATURE_MATCH);
+        installFromRawResource("install.apk", rapk2, PackageManager.INSTALL_REPLACE_EXISTING, true,
+                fail, retCode, PackageInfo.INSTALL_LOCATION_UNSPECIFIED);
+    }
     /*---------- Recommended install location tests ----*/
     /*
      * TODO's
diff --git a/services/java/com/android/server/PackageManagerService.java b/services/java/com/android/server/PackageManagerService.java
index 9e0f0ed976ace..8c4bca9306c93 100644
--- a/services/java/com/android/server/PackageManagerService.java
+++ b/services/java/com/android/server/PackageManagerService.java
@@ -1835,21 +1835,19 @@ class PackageManagerService extends IPackageManager.Stub {
         if (s2 == null) {
             return PackageManager.SIGNATURE_SECOND_NOT_SIGNED;
         }
-        final int N1 = s1.length;
-        final int N2 = s2.length;
-        for (int i=0; i<N1; i++) {
-            boolean match = false;
-            for (int j=0; j<N2; j++) {
-                if (s1[i].equals(s2[j])) {
-                    match = true;
-                    break;
-                }
-            }
-            if (!match) {
-                return PackageManager.SIGNATURE_NO_MATCH;
-            }
+        HashSet<Signature> set1 = new HashSet<Signature>();
+        for (Signature sig : s1) {
+            set1.add(sig);
         }
-        return PackageManager.SIGNATURE_MATCH;
+        HashSet<Signature> set2 = new HashSet<Signature>();
+        for (Signature sig : s2) {
+            set2.add(sig);
+        }
+        // Make sure s2 contains all signatures in s1.
+        if (set1.equals(set2)) {
+            return PackageManager.SIGNATURE_MATCH;
+        }
+        return PackageManager.SIGNATURE_NO_MATCH;
     }
 
     public String[] getPackagesForUid(int uid) {
@@ -2501,6 +2499,9 @@ class PackageManagerService extends IPackageManager.Stub {
                     mLastScanError = pp.getParseError();
                     return false;
                 }
+            } else {
+                // Lets implicitly assign existing certificates.
+                pkg.mSignatures = ps.signatures.mSignatures;
             }
         }
         return true;
@@ -2629,28 +2630,27 @@ class PackageManagerService extends IPackageManager.Stub {
     }
 
     private boolean verifySignaturesLP(PackageSetting pkgSetting,
-            PackageParser.Package pkg, int parseFlags, boolean updateSignature) {
-        if (pkg.mSignatures != null) {
-            if (!pkgSetting.signatures.updateSignatures(pkg.mSignatures,
-                    updateSignature)) {
-                Slog.e(TAG, "Package " + pkg.packageName
-                        + " signatures do not match the previously installed version; ignoring!");
-                mLastScanError = PackageManager.INSTALL_FAILED_UPDATE_INCOMPATIBLE;
-                return false;
-            }
-
-            if (pkgSetting.sharedUser != null) {
-                if (!pkgSetting.sharedUser.signatures.mergeSignatures(
-                        pkg.mSignatures, updateSignature)) {
+            PackageParser.Package pkg) {
+        if (pkgSetting.signatures.mSignatures != null) {
+            // Already existing package. Make sure signatures match
+            if (checkSignaturesLP(pkgSetting.signatures.mSignatures, pkg.mSignatures) !=
+                PackageManager.SIGNATURE_MATCH) {
                     Slog.e(TAG, "Package " + pkg.packageName
-                            + " has no signatures that match those in shared user "
-                            + pkgSetting.sharedUser.name + "; ignoring!");
-                    mLastScanError = PackageManager.INSTALL_FAILED_SHARED_USER_INCOMPATIBLE;
+                            + " signatures do not match the previously installed version; ignoring!");
+                    mLastScanError = PackageManager.INSTALL_FAILED_UPDATE_INCOMPATIBLE;
                     return false;
                 }
+        }
+        // Check for shared user signatures
+        if (pkgSetting.sharedUser != null && pkgSetting.sharedUser.signatures.mSignatures != null) {
+            if (checkSignaturesLP(pkgSetting.sharedUser.signatures.mSignatures,
+                    pkg.mSignatures) != PackageManager.SIGNATURE_MATCH) {
+                Slog.e(TAG, "Package " + pkg.packageName
+                        + " has no signatures that match those in shared user "
+                        + pkgSetting.sharedUser.name + "; ignoring!");
+                mLastScanError = PackageManager.INSTALL_FAILED_SHARED_USER_INCOMPATIBLE;
+                return false;
             }
-        } else {
-            pkg.mSignatures = pkgSetting.signatures.mSignatures;
         }
         return true;
     }
@@ -2996,10 +2996,8 @@ class PackageManagerService extends IPackageManager.Stub {
             pkg.applicationInfo.uid = pkgSetting.userId;
             pkg.mExtras = pkgSetting;
 
-            if (!verifySignaturesLP(pkgSetting, pkg, parseFlags,
-                    (scanMode&SCAN_UPDATE_SIGNATURE) != 0)) {
+            if (!verifySignaturesLP(pkgSetting, pkg)) {
                 if ((parseFlags&PackageParser.PARSE_IS_SYSTEM_DIR) == 0) {
-                    mLastScanError = PackageManager.INSTALL_FAILED_UPDATE_INCOMPATIBLE;
                     return null;
                 }
                 // The signature has changed, but this package is in the system
@@ -3011,8 +3009,9 @@ class PackageManagerService extends IPackageManager.Stub {
                 // associated with an overall shared user, which doesn't seem all
                 // that unreasonable.
                 if (pkgSetting.sharedUser != null) {
-                    if (!pkgSetting.sharedUser.signatures.mergeSignatures(
-                            pkg.mSignatures, false)) {
+                    if (checkSignaturesLP(pkgSetting.sharedUser.signatures.mSignatures,
+                            pkg.mSignatures) != PackageManager.SIGNATURE_MATCH) {
+                        Log.w(TAG, "Signature mismatch for shared user : " + pkgSetting.sharedUser);
                         mLastScanError = PackageManager.INSTALL_PARSE_FAILED_INCONSISTENT_CERTIFICATES;
                         return null;
                     }
@@ -5543,7 +5542,7 @@ class PackageManagerService extends IPackageManager.Stub {
         // First find the old package info and check signatures
         synchronized(mPackages) {
             oldPackage = mPackages.get(pkgName);
-            if (checkSignaturesLP(pkg.mSignatures, oldPackage.mSignatures)
+            if (checkSignaturesLP(oldPackage.mSignatures, pkg.mSignatures)
                     != PackageManager.SIGNATURE_MATCH) {
                 res.returnCode = PackageManager.INSTALL_PARSE_FAILED_INCONSISTENT_CERTIFICATES;
                 return;
@@ -5571,7 +5570,6 @@ class PackageManagerService extends IPackageManager.Stub {
             oldInstallerPackageName = mSettings.getInstallerPackageName(pkgName);
         }
 
-        parseFlags |= PackageManager.INSTALL_REPLACE_EXISTING;
         // First delete the existing package while retaining the data directory
         if (!deletePackageLI(pkgName, true, PackageManager.DONT_DELETE_DATA,
                 res.removedInfo)) {
@@ -5595,20 +5593,7 @@ class PackageManagerService extends IPackageManager.Stub {
             }
         }
 
-        if (res.returnCode == PackageManager.INSTALL_SUCCEEDED) {
-            // If we deleted an exisiting package, the old source and resource files that we
-            // were keeping around in case we needed them (see below) can now be deleted.
-            // This info will be set on the res.removedInfo to clean up later on as post
-            // install action.
-
-            //update signature on the new package setting
-            //this should always succeed, since we checked the
-            //signature earlier.
-            synchronized(mPackages) {
-                verifySignaturesLP(mSettings.mPackages.get(pkgName), pkg,
-                        parseFlags, true);
-            }
-        } else {
+        if (res.returnCode != PackageManager.INSTALL_SUCCEEDED) {
             // remove package from internal structures.  Note that we want deletePackageX to
             // delete the package data and cache directories that it created in
             // scanPackageLocked, unless those directories existed before we even tried to
@@ -5627,19 +5612,23 @@ class PackageManagerService extends IPackageManager.Stub {
                     Slog.e(TAG, "Failed allocating storage when restoring pkg : " + pkgName);
                     return;
                 }
-                PackageInstalledInfo restoreRes = new PackageInstalledInfo();
-                restoreRes.removedInfo = new PackageRemovedInfo();
                 // Parse old package
-                parseFlags &= ~PackageManager.INSTALL_REPLACE_EXISTING;
-                scanPackageLI(restoreFile, parseFlags, scanMode);
+                boolean oldOnSd = isExternal(deletedPackage);
+                int oldParseFlags  = mDefParseFlags | PackageParser.PARSE_CHATTY |
+                        (isForwardLocked(deletedPackage) ? PackageParser.PARSE_FORWARD_LOCK : 0) |
+                        (oldOnSd ? PackageParser.PARSE_ON_SDCARD : 0);
+                int oldScanMode = (oldOnSd ? 0 : SCAN_MONITOR) | SCAN_UPDATE_SIGNATURE;
+                if (scanPackageLI(restoreFile, oldParseFlags, oldScanMode) == null) {
+                    Slog.e(TAG, "Failed to restore package : " + pkgName + " after failed upgrade");
+                    return;
+                }
+                // Restore of old package succeeded. Update permissions.
                 synchronized (mPackages) {
                     updatePermissionsLP(deletedPackage.packageName, deletedPackage,
                             true, false);
                     mSettings.writeLP();
                 }
-                if (restoreRes.returnCode != PackageManager.INSTALL_SUCCEEDED) {
-                    Slog.e(TAG, "Failed restoring pkg : " + pkgName + " after failed upgrade");
-                }
+                Slog.i(TAG, "Successfully restored package : " + pkgName + " after failed upgrade");
             }
         }
     }
@@ -5691,15 +5680,7 @@ class PackageManagerService extends IPackageManager.Stub {
             updatedSettings = true;
         }
 
-        if (res.returnCode == PackageManager.INSTALL_SUCCEEDED) {
-            //update signature on the new package setting
-            //this should always succeed, since we checked the
-            //signature earlier.
-            synchronized(mPackages) {
-                verifySignaturesLP(mSettings.mPackages.get(packageName), pkg,
-                        parseFlags, true);
-            }
-        } else {
+        if (res.returnCode != PackageManager.INSTALL_SUCCEEDED) {
             // Re installation failed. Restore old information
             // Remove new pkg information
             if (newPackage != null) {
@@ -5781,7 +5762,7 @@ class PackageManagerService extends IPackageManager.Stub {
         boolean forwardLocked = ((pFlags & PackageManager.INSTALL_FORWARD_LOCK) != 0);
         boolean onSd = ((pFlags & PackageManager.INSTALL_EXTERNAL) != 0);
         boolean replace = false;
-        int scanMode = SCAN_MONITOR | SCAN_FORCE_DEX | SCAN_UPDATE_SIGNATURE
+        int scanMode = (onSd ? 0 : SCAN_MONITOR) | SCAN_FORCE_DEX | SCAN_UPDATE_SIGNATURE
                 | (newInstall ? SCAN_NEW_INSTALL : 0);
         // Result object to be returned
         res.returnCode = PackageManager.INSTALL_SUCCEEDED;
@@ -5911,6 +5892,10 @@ class PackageManagerService extends IPackageManager.Stub {
         return  ((pkg.applicationInfo.flags & ApplicationInfo.FLAG_FORWARD_LOCK) != 0);
     }
 
+    private boolean isExternal(PackageParser.Package pkg) {
+        return  ((pkg.applicationInfo.flags & ApplicationInfo.FLAG_EXTERNAL_STORAGE) != 0);
+    }
+
     private void extractPublicFiles(PackageParser.Package newPackage,
                                     File publicZipFile) throws IOException {
         final ZipOutputStream publicZipOutStream =
@@ -7345,101 +7330,6 @@ class PackageManagerService extends IPackageManager.Stub {
             }
         }
 
-        /**
-         * If any of the given 'sigs' is contained in the existing signatures,
-         * then completely replace the current signatures with the ones in
-         * 'sigs'.  This is used for updating an existing package to a newly
-         * installed version.
-         */
-        boolean updateSignatures(Signature[] sigs, boolean update) {
-            if (mSignatures == null) {
-                if (update) {
-                    assignSignatures(sigs);
-                }
-                return true;
-            }
-            if (sigs == null) {
-                return false;
-            }
-
-            for (int i=0; i<sigs.length; i++) {
-                Signature sig = sigs[i];
-                for (int j=0; j<mSignatures.length; j++) {
-                    if (mSignatures[j].equals(sig)) {
-                        if (update) {
-                            assignSignatures(sigs);
-                        }
-                        return true;
-                    }
-                }
-            }
-            return false;
-        }
-
-        /**
-         * If any of the given 'sigs' is contained in the existing signatures,
-         * then add in any new signatures found in 'sigs'.  This is used for
-         * including a new package into an existing shared user id.
-         */
-        boolean mergeSignatures(Signature[] sigs, boolean update) {
-            if (mSignatures == null) {
-                if (update) {
-                    assignSignatures(sigs);
-                }
-                return true;
-            }
-            if (sigs == null) {
-                return false;
-            }
-
-            Signature[] added = null;
-            int addedCount = 0;
-            boolean haveMatch = false;
-            for (int i=0; i<sigs.length; i++) {
-                Signature sig = sigs[i];
-                boolean found = false;
-                for (int j=0; j<mSignatures.length; j++) {
-                    if (mSignatures[j].equals(sig)) {
-                        found = true;
-                        haveMatch = true;
-                        break;
-                    }
-                }
-
-                if (!found) {
-                    if (added == null) {
-                        added = new Signature[sigs.length];
-                    }
-                    added[i] = sig;
-                    addedCount++;
-                }
-            }
-
-            if (!haveMatch) {
-                // Nothing matched -- reject the new signatures.
-                return false;
-            }
-            if (added == null) {
-                // Completely matched -- nothing else to do.
-                return true;
-            }
-
-            // Add additional signatures in.
-            if (update) {
-                Signature[] total = new Signature[addedCount+mSignatures.length];
-                System.arraycopy(mSignatures, 0, total, 0, mSignatures.length);
-                int j = mSignatures.length;
-                for (int i=0; i<added.length; i++) {
-                    if (added[i] != null) {
-                        total[j] = added[i];
-                        j++;
-                    }
-                }
-                mSignatures = total;
-            }
-            return true;
-        }
-
         private void assignSignatures(Signature[] sigs) {
             if (sigs == null) {
                 mSignatures = null;
@@ -8227,6 +8117,15 @@ class PackageManagerService extends IPackageManager.Stub {
              if (pkg.mVersionCode != p.versionCode) {
                 p.versionCode = pkg.mVersionCode;
             }
+             // Update signatures if needed.
+             if (p.signatures.mSignatures == null) {
+                 p.signatures.assignSignatures(pkg.mSignatures);
+             }
+             // If this app defines a shared user id initialize
+             // the shared user signatures as well.
+             if (p.sharedUser != null && p.sharedUser.signatures.mSignatures == null) {
+                 p.sharedUser.signatures.assignSignatures(pkg.mSignatures);
+             }
             addPackageSettingLP(p, pkg.packageName, p.sharedUser);
         }
 
@@ -9655,22 +9554,12 @@ class PackageManagerService extends IPackageManager.Stub {
                // Parse package
                int parseFlags = PackageParser.PARSE_CHATTY |
                        PackageParser.PARSE_ON_SDCARD | mDefParseFlags;
-               PackageParser pp = new PackageParser(codePath);
-               pp.setSeparateProcesses(mSeparateProcesses);
-               final PackageParser.Package pkg = pp.parsePackage(new File(codePath),
-                       codePath, mMetrics, parseFlags);
-               pp = null;
                doGc = true;
-               // Check for parse errors
-               if (pkg == null) {
-                   Slog.e(TAG, "Parse error when installing install pkg : "
-                           + args.cid + " from " + args.cachePath);
-                   continue;
-               }
-               setApplicationInfoPaths(pkg, codePath, codePath);
                synchronized (mInstallLock) {
+                   final PackageParser.Package pkg =  scanPackageLI(new File(codePath),
+                           parseFlags, 0);
                    // Scan the package
-                   if (scanPackageLI(pkg, parseFlags, SCAN_MONITOR) != null) {
+                   if (pkg != null) {
                        synchronized (mPackages) {
                            retCode = PackageManager.INSTALL_SUCCEEDED;
                            pkgList.add(pkg.packageName);
@@ -9678,8 +9567,8 @@ class PackageManagerService extends IPackageManager.Stub {
                            args.doPostInstall(PackageManager.INSTALL_SUCCEEDED);
                        }
                    } else {
-                       Slog.i(TAG, "Failed to install pkg: " +
-                               pkg.packageName + " from sdcard");
+                       Slog.i(TAG, "Failed to install pkg from  " +
+                               codePath + " from sdcard");
                    }
                }