Fix TrustedCredentialsSettings NPE

[Cause of Defect]
TrustedCredentialsSettings#mKeyChainConnectionByProfileId is get/set by
more than one thread. Main thread would set it in onDestroy method, and
AsyncTask would get and set in the doInBackground method. So
mKeyChainConnectionByProfileId.get(profileId) would get null after
onDestroy method get called.

Bug: N/A
Test: Debugger to simulate concurrency
Change-Id: I0664d1e9b88b079855354ce0e6fe014a98a22327
Signed-off-by: daqi <daqi@xiaomi.com>

1 files changed, 86 insertions, 76 deletions

diff --git a/src/com/android/settings/TrustedCredentialsSettings.java b/src/com/android/settings/TrustedCredentialsSettings.java
index 4696dd317b..587e814e2f 100644
--- a/src/com/android/settings/TrustedCredentialsSettings.java
+++ b/src/com/android/settings/TrustedCredentialsSettings.java
@@ -61,6 +61,7 @@ import android.widget.Switch;
 import android.widget.TabHost;
 import android.widget.TextView;
 
+import com.android.internal.annotations.GuardedBy;
 import com.android.internal.app.UnlaunchableAppActivity;
 import com.android.internal.logging.nano.MetricsProto.MetricsEvent;
 import com.android.internal.widget.LockPatternUtils;
@@ -152,6 +153,7 @@ public class TrustedCredentialsSettings extends OptionsMenuFragment
     private int mConfirmingCredentialUser;
     private IntConsumer mConfirmingCredentialListener;
     private Set<AdapterData.AliasLoader> mAliasLoaders = new ArraySet<AdapterData.AliasLoader>(2);
+    @GuardedBy("mKeyChainConnectionByProfileId")
     private final SparseArray<KeyChainConnection>
             mKeyChainConnectionByProfileId = new SparseArray<KeyChainConnection>();
 
@@ -256,11 +258,13 @@ public class TrustedCredentialsSettings extends OptionsMenuFragment
     }
 
     private void closeKeyChainConnections() {
-        final int n = mKeyChainConnectionByProfileId.size();
-        for (int i = 0; i < n; ++i) {
-            mKeyChainConnectionByProfileId.valueAt(i).close();
+        synchronized (mKeyChainConnectionByProfileId) {
+            final int n = mKeyChainConnectionByProfileId.size();
+            for (int i = 0; i < n; ++i) {
+                mKeyChainConnectionByProfileId.valueAt(i).close();
+            }
+            mKeyChainConnectionByProfileId.clear();
         }
-        mKeyChainConnectionByProfileId.clear();
     }
 
     private void addTab(Tab tab) {
@@ -684,62 +688,64 @@ public class TrustedCredentialsSettings extends OptionsMenuFragment
                 SparseArray<List<CertHolder>> certHoldersByProfile =
                         new SparseArray<List<CertHolder>>();
                 try {
-                    List<UserHandle> profiles = mUserManager.getUserProfiles();
-                    final int n = profiles.size();
-                    // First we get all aliases for all profiles in order to show progress
-                    // correctly. Otherwise this could all be in a single loop.
-                    SparseArray<List<String>> aliasesByProfileId = new SparseArray<
-                            List<String>>(n);
-                    int max = 0;
-                    int progress = 0;
-                    for (int i = 0; i < n; ++i) {
-                        UserHandle profile = profiles.get(i);
-                        int profileId = profile.getIdentifier();
-                        if (shouldSkipProfile(profile)) {
-                            continue;
-                        }
-                        KeyChainConnection keyChainConnection = KeyChain.bindAsUser(mContext,
-                                profile);
-                        // Saving the connection for later use on the certificate dialog.
-                        mKeyChainConnectionByProfileId.put(profileId, keyChainConnection);
-                        IKeyChainService service = keyChainConnection.getService();
-                        List<String> aliases = mTab.getAliases(service);
-                        if (isCancelled()) {
-                            return new SparseArray<List<CertHolder>>();
-                        }
-                        max += aliases.size();
-                        aliasesByProfileId.put(profileId, aliases);
-                    }
-                    for (int i = 0; i < n; ++i) {
-                        UserHandle profile = profiles.get(i);
-                        int profileId = profile.getIdentifier();
-                        List<String> aliases = aliasesByProfileId.get(profileId);
-                        if (isCancelled()) {
-                            return new SparseArray<List<CertHolder>>();
-                        }
-                        KeyChainConnection keyChainConnection = mKeyChainConnectionByProfileId.get(
-                                profileId);
-                        if (shouldSkipProfile(profile) || aliases == null
-                                || keyChainConnection == null) {
-                            certHoldersByProfile.put(profileId, new ArrayList<CertHolder>(0));
-                            continue;
+                    synchronized(mKeyChainConnectionByProfileId) {
+                        List<UserHandle> profiles = mUserManager.getUserProfiles();
+                        final int n = profiles.size();
+                        // First we get all aliases for all profiles in order to show progress
+                        // correctly. Otherwise this could all be in a single loop.
+                        SparseArray<List<String>> aliasesByProfileId = new SparseArray<
+                                List<String>>(n);
+                        int max = 0;
+                        int progress = 0;
+                        for (int i = 0; i < n; ++i) {
+                            UserHandle profile = profiles.get(i);
+                            int profileId = profile.getIdentifier();
+                            if (shouldSkipProfile(profile)) {
+                                continue;
+                            }
+                            KeyChainConnection keyChainConnection = KeyChain.bindAsUser(mContext,
+                                    profile);
+                            // Saving the connection for later use on the certificate dialog.
+                            mKeyChainConnectionByProfileId.put(profileId, keyChainConnection);
+                            IKeyChainService service = keyChainConnection.getService();
+                            List<String> aliases = mTab.getAliases(service);
+                            if (isCancelled()) {
+                                return new SparseArray<List<CertHolder>>();
+                            }
+                            max += aliases.size();
+                            aliasesByProfileId.put(profileId, aliases);
                         }
-                        IKeyChainService service = keyChainConnection.getService();
-                        List<CertHolder> certHolders = new ArrayList<CertHolder>(max);
-                        final int aliasMax = aliases.size();
-                        for (int j = 0; j < aliasMax; ++j) {
-                            String alias = aliases.get(j);
-                            byte[] encodedCertificate = service.getEncodedCaCertificate(alias,
-                                    true);
-                            X509Certificate cert = KeyChain.toCertificate(encodedCertificate);
-                            certHolders.add(new CertHolder(service, mAdapter,
-                                    mTab, alias, cert, profileId));
-                            publishProgress(++progress, max);
+                        for (int i = 0; i < n; ++i) {
+                            UserHandle profile = profiles.get(i);
+                            int profileId = profile.getIdentifier();
+                            List<String> aliases = aliasesByProfileId.get(profileId);
+                            if (isCancelled()) {
+                                return new SparseArray<List<CertHolder>>();
+                            }
+                            KeyChainConnection keyChainConnection = mKeyChainConnectionByProfileId.get(
+                                    profileId);
+                            if (shouldSkipProfile(profile) || aliases == null
+                                    || keyChainConnection == null) {
+                                certHoldersByProfile.put(profileId, new ArrayList<CertHolder>(0));
+                                continue;
+                            }
+                            IKeyChainService service = keyChainConnection.getService();
+                            List<CertHolder> certHolders = new ArrayList<CertHolder>(max);
+                            final int aliasMax = aliases.size();
+                            for (int j = 0; j < aliasMax; ++j) {
+                                String alias = aliases.get(j);
+                                byte[] encodedCertificate = service.getEncodedCaCertificate(alias,
+                                        true);
+                                X509Certificate cert = KeyChain.toCertificate(encodedCertificate);
+                                certHolders.add(new CertHolder(service, mAdapter,
+                                        mTab, alias, cert, profileId));
+                                publishProgress(++progress, max);
+                            }
+                            Collections.sort(certHolders);
+                            certHoldersByProfile.put(profileId, certHolders);
                         }
-                        Collections.sort(certHolders);
-                        certHoldersByProfile.put(profileId, certHolders);
+                        return certHoldersByProfile;
                     }
-                    return certHoldersByProfile;
                 } catch (RemoteException e) {
                     Log.e(TAG, "Remote exception while loading aliases.", e);
                     return new SparseArray<List<CertHolder>>();
@@ -936,16 +942,18 @@ public class TrustedCredentialsSettings extends OptionsMenuFragment
     public List<X509Certificate> getX509CertsFromCertHolder(CertHolder certHolder) {
         List<X509Certificate> certificates = null;
         try {
-            KeyChainConnection keyChainConnection = mKeyChainConnectionByProfileId.get(
-                    certHolder.mProfileId);
-            IKeyChainService service = keyChainConnection.getService();
-            List<String> chain = service.getCaCertificateChainAliases(certHolder.mAlias, true);
-            final int n = chain.size();
-            certificates = new ArrayList<X509Certificate>(n);
-            for (int i = 0; i < n; ++i) {
-                byte[] encodedCertificate = service.getEncodedCaCertificate(chain.get(i), true);
-                X509Certificate certificate = KeyChain.toCertificate(encodedCertificate);
-                certificates.add(certificate);
+            synchronized (mKeyChainConnectionByProfileId) {
+                KeyChainConnection keyChainConnection = mKeyChainConnectionByProfileId.get(
+                        certHolder.mProfileId);
+                IKeyChainService service = keyChainConnection.getService();
+                List<String> chain = service.getCaCertificateChainAliases(certHolder.mAlias, true);
+                final int n = chain.size();
+                certificates = new ArrayList<X509Certificate>(n);
+                for (int i = 0; i < n; ++i) {
+                    byte[] encodedCertificate = service.getEncodedCaCertificate(chain.get(i), true);
+                    X509Certificate certificate = KeyChain.toCertificate(encodedCertificate);
+                    certificates.add(certificate);
+                }
             }
         } catch (RemoteException ex) {
             Log.e(TAG, "RemoteException while retrieving certificate chain for root "
@@ -985,15 +993,17 @@ public class TrustedCredentialsSettings extends OptionsMenuFragment
         @Override
         protected Boolean doInBackground(Void... params) {
             try {
-                KeyChainConnection keyChainConnection = mKeyChainConnectionByProfileId.get(
-                        mCertHolder.mProfileId);
-                IKeyChainService service = keyChainConnection.getService();
-                if (mCertHolder.mDeleted) {
-                    byte[] bytes = mCertHolder.mX509Cert.getEncoded();
-                    service.installCaCertificate(bytes);
-                    return true;
-                } else {
-                    return service.deleteCaCertificate(mCertHolder.mAlias);
+                synchronized (mKeyChainConnectionByProfileId) {
+                    KeyChainConnection keyChainConnection = mKeyChainConnectionByProfileId.get(
+                            mCertHolder.mProfileId);
+                    IKeyChainService service = keyChainConnection.getService();
+                    if (mCertHolder.mDeleted) {
+                        byte[] bytes = mCertHolder.mX509Cert.getEncoded();
+                        service.installCaCertificate(bytes);
+                        return true;
+                    } else {
+                        return service.deleteCaCertificate(mCertHolder.mAlias);
+                    }
                 }
             } catch (CertificateEncodingException | SecurityException | IllegalStateException
                     | RemoteException e) {