Why signatures is null?

Question

Good day!
I tried this code :

PackageInfo info = mContext.getPackageManager().getPackageArchiveInfo(absolute_apk_name, PackageManager.GET_SIGNATURES);
        if (info != null)
        {
            Signature[] sig = info.signatures;
            if (sig != null)
                sigstring = new String(sig[0].toChars());
        }

But info.signatures == null, and I do not have any idea "why?"
File in absolute_apk_name exists, I checked Android 2.1

UPD:

absolute_apk_name = "/data/data/ru.UseIT.SimpleFormsLauncher/files/SimpleFormsGeneral.apk"

apk was created with flags Context.MODE_WORLD_READABLE|Context.MODE_WORLD_WRITEABLE

But if exec this code

Intent intent = new Intent(Intent.ACTION_VIEW);
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        intent.setDataAndType(Uri.fromFile(new File(absolute_apk_name )), "application/vnd.android.package-archive");
        mContext.startActivity(intent);

It was installed.

How about GET_PERMISSIONS. I know all files have permissions so try that. — DrinkJavaCodeJava, Mar 19 '13 at 15:15
@DrinkJavaCodeJava, can I see example? Just don't understand — andreich, Mar 19 '13 at 15:16
What are you trying to accomplish? I don't understand why you're checking to see if the sig array is null. — , May 26 '13 at 05:22
What are the contents of your manifest? Do you have the right permissions (for your Android version)? — andy256, Jul 11 '13 at 03:04

score 1 · Answer 1 · answered Jan 06 '14 at 02:47

1

it is an android system bug see this https://code.google.com/p/android/issues/detail?id=9151#c8 this bug has fixed on 4.0+

answered Jan 06 '14 at 02:47

yichouangle

61
4

score 1 · Accepted Answer · answered Jun 17 '14 at 08:33

I checked the Android source, and it turns out that PackageManager#getPackageArchiveInfo(String, int) does not include signatures if Android version is 2.3.7 and less.

Please look below links.

http://tools.oesf.biz/android-2.3.7_r1.0/xref/frameworks/base/core/java/android/content/pm/PackageManager.java#1891

http://tools.oesf.biz/android-4.0.3_r1.0/xref/frameworks/base/core/java/android/content/pm/PackageManager.java#2121

score -1 · Answer 3 · answered Jul 17 '13 at 08:53

-1

I'm not quite sure what your trying to achieve, but using the absolute apk name/path is incorrect, you need the packagename. I've been able to get the signatures using the following, just replace "com.android.chrome" with the package name of the app you want.

final PackageInfo pkgInfo = packageManager.getPackageInfo(
                    "com.android.chrome", PackageManager.GET_SIGNATURES);
final Signature[] signatures = pkgInfo.signatures;

answered Jul 17 '13 at 08:53

scottyab

23,621
16
94
105

I'm trying to get the signature of another apk, not installed – andreich Aug 15 '13 at 07:40
maybe use openssl to get the cert? http://stackoverflow.com/questions/4324120/how-to-view-the-identity-of-person-who-signed-the-apk-on-android-device – scottyab Aug 15 '13 at 15:44
Wait are you doing this on the device? and trying to verify the signature of apk before installation? – scottyab Aug 15 '13 at 15:45
Yes, before installation:) – andreich Aug 15 '13 at 16:55
looks like you're using the wrong Api then. PackageManager is for installed apps. – josephus Jan 06 '14 at 02:50
This is not true at all. As mentioned above early versions of android just wont return the signatures. – Sam Shute Dec 02 '14 at 02:54

Why signatures is null?

3 Answers3