diff --git a/luni/src/test/java/libcore/java/util/zip/ZipFileTest.java b/luni/src/test/java/libcore/java/util/zip/ZipFileTest.java
index 02210ac..03fa29a 100644
--- a/luni/src/test/java/libcore/java/util/zip/ZipFileTest.java
+++ b/luni/src/test/java/libcore/java/util/zip/ZipFileTest.java
@@ -16,7 +16,18 @@
 
 package libcore.java.util.zip;
 
+import android.system.OsConstants;
+import libcore.io.Libcore;
+
+import java.io.BufferedOutputStream;
+import java.io.File;
+import java.io.FileDescriptor;
+import java.io.FileOutputStream;
+import java.io.InputStream;
 import java.io.OutputStream;
+import java.util.Enumeration;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipFile;
 import java.util.zip.ZipOutputStream;
 
 public final class ZipFileTest extends AbstractZipFileTest {
@@ -25,4 +36,42 @@
     protected ZipOutputStream createZipOutputStream(OutputStream wrapped) {
         return new ZipOutputStream(wrapped);
     }
+
+    // http://b/30407219
+    public void testZipFileOffsetNeverChangesAfterInit() throws Exception {
+        final File f = createTemporaryZipFile();
+        writeEntries(createZipOutputStream(new BufferedOutputStream(new FileOutputStream(f))),
+                2 /* number of entries */, 1024 /* entry size */, true /* setEntrySize */);
+
+        ZipFile zipFile = new ZipFile(f);
+        FileDescriptor fd = new FileDescriptor();
+        fd.setInt$(zipFile.getFileDescriptor());
+
+        long initialOffset = android.system.Os.lseek(fd, 0, OsConstants.SEEK_CUR);
+
+        Enumeration<? extends ZipEntry> entries = zipFile.entries();
+        assertOffset(initialOffset, fd);
+
+        // Get references to the two elements in the file.
+        ZipEntry entry1 = entries.nextElement();
+        ZipEntry entry2 = entries.nextElement();
+        assertFalse(entries.hasMoreElements());
+        assertOffset(initialOffset, fd);
+
+        InputStream is1 = zipFile.getInputStream(entry1);
+        assertOffset(initialOffset, fd);
+        is1.read(new byte[256]);
+        assertOffset(initialOffset, fd);
+        is1.close();
+
+        assertNotNull(zipFile.getEntry(entry2.getName()));
+        assertOffset(initialOffset, fd);
+
+        zipFile.close();
+    }
+
+    private static void assertOffset(long initialOffset, FileDescriptor fd) throws Exception {
+        long currentOffset = android.system.Os.lseek(fd, 0, OsConstants.SEEK_CUR);
+        assertEquals(initialOffset, currentOffset);
+    }
 }
diff --git a/ojluni/src/main/java/java/util/zip/ZipFile.java b/ojluni/src/main/java/java/util/zip/ZipFile.java
index e6624af..9ff661a 100755
--- a/ojluni/src/main/java/java/util/zip/ZipFile.java
+++ b/ojluni/src/main/java/java/util/zip/ZipFile.java
@@ -771,6 +771,14 @@
         return locsig;
     }
 
+    /** @hide */
+    // @VisibleForTesting
+    public int getFileDescriptor() {
+        return getFileDescriptor(jzfile);
+    }
+
+    private static native int getFileDescriptor(long jzfile);
+
     private static native long open(String name, int mode, long lastModified,
                                     boolean usemmap) throws IOException;
     private static native int getTotal(long jzfile);
diff --git a/ojluni/src/main/native/java_util_zip_ZipFile.c b/ojluni/src/main/native/java_util_zip_ZipFile.c
index 7280d97..5353ff4 100644
--- a/ojluni/src/main/native/java_util_zip_ZipFile.c
+++ b/ojluni/src/main/native/java_util_zip_ZipFile.c
@@ -156,6 +156,12 @@
     ZIP_Close(jlong_to_ptr(zfile));
 }
 
+JNIEXPORT jint JNICALL
+ZipFile_getFileDescriptor(JNIEnv *env, jclass cls, jlong zfile) {
+    jzfile *zip = jlong_to_ptr(zfile);
+    return zip->zfd;
+}
+
 JNIEXPORT jlong JNICALL
 ZipFile_getEntry(JNIEnv *env, jclass cls, jlong zfile,
                  jbyteArray name, jboolean addSlash)
@@ -390,6 +396,7 @@
 }
 
 static JNINativeMethod gMethods[] = {
+  NATIVE_METHOD(ZipFile, getFileDescriptor, "(J)I"),
   NATIVE_METHOD(ZipFile, getEntry, "(J[BZ)J"),
   NATIVE_METHOD(ZipFile, freeEntry, "(JJ)V"),
   NATIVE_METHOD(ZipFile, getNextEntry, "(JI)J"),
diff --git a/ojluni/src/main/native/zip_util.c b/ojluni/src/main/native/zip_util.c
index 66ce7e5..36f2d26 100644
--- a/ojluni/src/main/native/zip_util.c
+++ b/ojluni/src/main/native/zip_util.c
@@ -144,7 +144,7 @@
 }
 
 static int
-ZFILE_read(ZFILE zfd, char *buf, jint nbytes) {
+ZFILE_read(ZFILE zfd, char *buf, jint nbytes, jlong offset) {
 #ifdef WIN32
     return (int) IO_Read(zfd, buf, nbytes);
 #else
@@ -156,7 +156,7 @@
      * JVM_IO_INTR is tricky and could cause undesired side effect. So we decided
      * to simply call "read" on Solaris/Linux. See details in bug 6304463.
      */
-    return read(zfd, buf, nbytes);
+    return pread(zfd, buf, nbytes, offset);
 #endif
 }
 
@@ -185,11 +185,11 @@
 }
 
 /*
- * Reads len bytes of data into buf.
+ * Reads len bytes of data from the specified offset into buf.
  * Returns 0 if all bytes could be read, otherwise returns -1.
  */
 static int
-readFully(ZFILE zfd, void *buf, jlong len) {
+readFullyAt(ZFILE zfd, void *buf, jlong len, jlong offset) {
   char *bp = (char *) buf;
 
   while (len > 0) {
@@ -197,9 +197,10 @@
         jint count = (len < limit) ?
             (jint) len :
             (jint) limit;
-        jint n = ZFILE_read(zfd, bp, count);
+        jint n = ZFILE_read(zfd, bp, count, offset);
         if (n > 0) {
             bp += n;
+            offset += n;
             len -= n;
         } else if (n == JVM_IO_ERR && errno == EINTR) {
           /* Retry after EINTR (interrupted by signal).
@@ -212,19 +213,6 @@
     return 0;
 }
 
-/*
- * Reads len bytes of data from the specified offset into buf.
- * Returns 0 if all bytes could be read, otherwise returns -1.
- */
-static int
-readFullyAt(ZFILE zfd, void *buf, jlong len, jlong offset)
-{
-    if (IO_Lseek(zfd, offset, SEEK_SET) == -1) {
-        return -1; /* lseek failure. */
-    }
-
-    return readFully(zfd, buf, len);
-}
 
 /*
  * Allocates a new zip file object for the specified file name.
@@ -879,14 +867,17 @@
         return NULL;
     }
 
-    // Assumption, zfd refers to start of file. Trivially, reuse errbuf.
-    if (readFully(zfd, errbuf, 4) != -1) {  // errors will be handled later
+    // Trivially, reuse errbuf.
+    if (readFullyAt(zfd, errbuf, 4, 0 /* offset */) != -1) {  // errors will be handled later
         if (GETSIG(errbuf) == LOCSIG)
             zip->locsig = JNI_TRUE;
         else
             zip->locsig = JNI_FALSE;
     }
 
+    // This lseek is safe because it happens during construction of the ZipFile
+    // object. We must take care not to perform any operations that change the
+    // offset after (see b/30407219).
     len = zip->len = IO_Lseek(zfd, 0, SEEK_END);
     if (len <= 0) {
         if (len == 0) { /* zip file is empty */
@@ -986,7 +977,7 @@
     censize = CENSIZE(cen);
     if (censize <= bufsize) return cen;
     if ((cen = realloc(cen, censize)) == NULL)              goto Catch;
-    if (readFully(zfd, cen+bufsize, censize-bufsize) == -1) goto Catch;
+    if (readFullyAt(zfd, cen+bufsize, censize-bufsize, cenpos + bufsize) == -1) goto Catch;
     return cen;
 
  Catch: