Android 验证APK签名对比

最近OTT制定产品，其中有一条需求是只能安装自己公司签名的APK，所以在网上找了相关资料，最后总结功能实现如下：

1、签名错误码
frameworks/base/core/java/android/content/pm/PackageManager.java
    public static final int INSTALL_FAILED_VERSION_DOWNGRADE = -25;  
    //添加签名错误码
    public static final int INSTALL_FAILED_INVALID_SIGNATURES = -26;

2、对比签名
frameworks/base/services/java/com/android/server/pm/PackageManagerService.java
    // 安装标识，区别打开APK和安装APK
    private boolean mIsInstallApkFlag = false;
    
    private void installPackageLI(InstallArgs args,  
            boolean newInstall, PackageInstalledInfo res) {  
            ...  
        Log.i(TAG, "Start installation for package: " + pkg.packageName);  
 
 //add start 设置安装标识       
    mIsInstallApkFlag = true;  
//add end
    if (replace) {  
            replacePackageLI(pkg, parseFlags, scanMode, args.user,  
                    installerPackageName, res);  
        } else {  
            installNewPackageLI(pkg, parseFlags, scanMode, args.user,  
                    installerPackageName, res);  
        }  
        Log.i(TAG, "Installation done for package: " + pkg.packageName);  
        ...  
    }
    
    private PackageParser.Package scanPackageLI(PackageParser.Package pkg,
            int parseFlags, int scanMode, long currentTime, UserHandle user) {
            ...
        if (!verifySignaturesLP(pkgSetting, pkg)) {
        ...
        }
    //add start 添加校验判断
           // is xhw signatures
            Signature[] xhwSignatures = getXWHSignatures(mContext,"com.ronbell.ott.setting");

if (xhwSignatures != null) {
                if (compareSignatures(xhwSignatures, pkg.mSignatures) != PackageManager.SIGNATURE_MATCH) {
                    mLastScanError = PackageManager.INSTALL_FAILED_INVALID_SIGNATURES;
                    return null;
                }
            }
    //add end

// Verify that this new package doesn't have any content providers
            // that conflict with existing packages.  Only do this if the
            // package isn't already installed, since we don't want to break
            // things that are installed.
            if ((scanMode&SCAN_NEW_INSTALL) != 0) {
           ...
    }    
    
    //add methods 添加获取安装签名
    private Signature[] getXWHSignatures(Context context, String packName){
        if(!isSignature) return null; // 判断只有在安装的时候才起作用。
        isSignature = false;
        PackageManager pm = context.getPackageManager();
        List<PackageInfo> apps = pm.getInstalledPackages(PackageManager.GET_SIGNATURES);
        Iterator<PackageInfo> it = apps.iterator();
        while(it.hasNext()){
            PackageInfo info = it.next();
            if(info.packageName.equals(packName)){
                return info.signatures;
            }
        }
        return null;
    }
    private boolean IsSignaturesSame(Signature[] s1, Signature[] s2) {
        if(s1 == null || s2 == null ) {
            return   false ;
        }
        HashSet < Signature >  set1  =   new  HashSet < Signature > ();
        for  (Signature sig : s1) {
            set1.add(sig);
        }
        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   true ;
        }
        return   false ;                      
    }
   
    //add end

3、安装失败提示
packages/apps/PackageInstaller/src/com/android/packageinstaller/InstallAppProgress.java

private Handler mHandler = new Handler() {
        public void handleMessage(Message msg) {
            switch (msg.what) {
            ...
//add start
                    } else if (msg.arg1 == PackageManager.INSTALL_FAILED_INVALID_SIGNATURES){
                        // Generic error handling for all other error codes.
                        centerTextDrawable.setLevel(1);
                        centerExplanationLabel = getExplanationFromErrorCode(msg.arg1);
                        centerTextLabel = R.string.install_failed_invalid_signature;
                        mLaunchButton.setVisibility(View.INVISIBLE);

} else {
                        // Generic error handling for all other error codes.
                        centerTextDrawable.setLevel(1);
                        centerExplanationLabel = getExplanationFromErrorCode(msg.arg1);
                        centerTextLabel = R.string.install_failed;
                        mLaunchButton.setVisibility(View.INVISIBLE);
                    }
                 ...