[ipsec-doze] Add fchown to IpSecService to support doze

Encap sockets are currently created as the system server, and should be
fchown'd to the user for whom it was created on behalf of.

Bug: 62994731
Test: New tests added and run to IpSecService
Change-Id: Icc49e709ae588981e69765fdb77537d7ffbac5fe

tests/net/java/com/android/server/IpSecServiceTest.java

@@ -475,4 +475,26 @@ public class IpSecServiceTest {
         testIpSecService.closeUdpEncapsulationSocket(udpEncapResp.resourceId);
         udpEncapResp.fileDescriptor.close();
     }
+
+    @Test
+    public void testOpenUdpEncapsulationSocketCallsSetEncapSocketOwner() throws Exception {
+        IpSecUdpEncapResponse udpEncapResp =
+                mIpSecService.openUdpEncapsulationSocket(0, new Binder());
+
+        FileDescriptor sockFd = udpEncapResp.fileDescriptor.getFileDescriptor();
+        ArgumentMatcher<FileDescriptor> fdMatcher = (arg) -> {
+                    try {
+                        StructStat sockStat = Os.fstat(sockFd);
+                        StructStat argStat = Os.fstat(arg);
+
+                        return sockStat.st_ino == argStat.st_ino
+                                && sockStat.st_dev == argStat.st_dev;
+                    } catch (ErrnoException e) {
+                        return false;
+                    }
+                };
+
+        verify(mMockNetd).ipSecSetEncapSocketOwner(argThat(fdMatcher), eq(Os.getuid()));
+        mIpSecService.closeUdpEncapsulationSocket(udpEncapResp.resourceId);
+    }
 }