bug 61294 -- prevent infinite loop in IOUtils' skipFully.

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1801844 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/poi/util/IOUtils.java

@@ -361,7 +361,7 @@ public final class IOUtils {
     }
 
     /**
-     * Skips bytes from a stream.  Returns -1L if EOF was hit before
+     * Skips bytes from a stream.  Returns -1L if len > available() or if EOF was hit before
      * the end of the stream.
      *
      * @param in inputstream
@@ -370,11 +370,22 @@ public final class IOUtils {
      * @throws IOException on IOException
      */
     public static long skipFully(InputStream in, long len) throws IOException {
-        int total = 0;
+        long total = 0;
         while (true) {
+            long toSkip = len-total;
+            //check that the stream has the toSkip available
+            //FileInputStream can mis-report 20k skipped on a 10k file
+            if (toSkip > in.available()) {
+                return -1L;
+            }
             long got = in.skip(len-total);
             if (got < 0) {
                 return -1L;
+            } else if (got == 0) {
+                got = fallBackToReadFully(len-total, in);
+                if (got < 0) {
+                    return -1L;
+                }
             }
             total += got;
             if (total == len) {
@@ -382,4 +393,24 @@ public final class IOUtils {
             }
         }
     }
+
+    //an InputStream can return 0 whether or not it hits EOF
+    //if it returns 0, back off to readFully to test for -1
+    private static long fallBackToReadFully(long lenToRead, InputStream in) throws IOException {
+        byte[] buffer = new byte[8192];
+        long readSoFar = 0;
+
+        while (true) {
+            int toSkip = (lenToRead > Integer.MAX_VALUE ||
+                    (lenToRead-readSoFar) > buffer.length) ? buffer.length : (int)(lenToRead-readSoFar);
+            long readNow = readFully(in, buffer, 0, toSkip);
+            if (readNow < toSkip) {
+                return -1L;
+            }
+            readSoFar += readNow;
+            if (readSoFar == lenToRead) {
+                return readSoFar;
+            }
+        }
+    }
 }

src/scratchpad/testcases/org/apache/poi/hemf/extractor/HemfExtractorTest.java

@@ -22,6 +22,8 @@ import static org.apache.poi.POITestCase.assertContains;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
 import java.io.InputStream;
 import java.util.HashSet;
 import java.util.Set;
@@ -34,6 +36,8 @@ import org.apache.poi.hemf.record.HemfHeader;
 import org.apache.poi.hemf.record.HemfRecord;
 import org.apache.poi.hemf.record.HemfRecordType;
 import org.apache.poi.hemf.record.HemfText;
+import org.apache.poi.util.IOUtils;
+import org.apache.poi.util.RecordFormatException;
 import org.junit.Test;
 
 public class HemfExtractorTest {
@@ -160,8 +164,37 @@ public class HemfExtractorTest {
         assertEquals(expectedParts.size(), foundExpected);
     }
 
-    /*
+
+
+    @Test(expected = RecordFormatException.class)
+    public void testInfiniteLoopOnFile() throws Exception {
+        InputStream is = null;
+        try {
+            is = POIDataSamples.getSpreadSheetInstance().openResourceAsStream("61294.emf");
+
+            HemfExtractor ex = new HemfExtractor(is);
+            for (HemfRecord record : ex) {
+
+            }
+        } finally {
+            IOUtils.closeQuietly(is);
+        }
+    }
+
+    @Test(expected = RecordFormatException.class)
+    public void testInfiniteLoopOnByteArray() throws Exception {
+        InputStream is = POIDataSamples.getSpreadSheetInstance().openResourceAsStream("61294.emf");
+        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        IOUtils.copy(is, bos);
+        is.close();
+
+        HemfExtractor ex = new HemfExtractor(new ByteArrayInputStream(bos.toByteArray()));
+        for (HemfRecord record : ex) {
+
+        }
+    }
+
+     /*
         govdocs1 064213.doc-0.emf contains an example of extextouta
      */
-
 }

src/testcases/org/apache/poi/util/TestIOUtils.java

@@ -0,0 +1,136 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+
+package org.apache.poi.util;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.Random;
+
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+/**
+ * Class to test IOUtils
+ */
+public final class TestIOUtils {
+    static File TMP = null;
+    static long SEED = new Random().nextLong();
+    static Random RANDOM = new Random(SEED);
+
+    @BeforeClass
+    public static void setUp() throws IOException {
+        TMP = File.createTempFile("poi-ioutils-", "");
+        OutputStream os = new FileOutputStream(TMP);
+        for (int i = 0; i < RANDOM.nextInt(10000); i++) {
+            os.write(RANDOM.nextInt((byte)127));
+        }
+        os.flush();
+        os.close();
+
+    }
+
+    @AfterClass
+    public static void tearDown() throws IOException {
+        TMP.delete();
+    }
+
+    @Test
+    public void testSkipFully() throws IOException {
+        InputStream is =  new FileInputStream(TMP);
+        long skipped = IOUtils.skipFully(is, 20000L);
+        assertEquals("seed: "+SEED, -1L, skipped);
+    }
+
+    @Test
+    public void testSkipFullyGtIntMax() throws IOException {
+        InputStream is =  new FileInputStream(TMP);
+        long skipped = IOUtils.skipFully(is, Integer.MAX_VALUE + 20000L);
+        assertEquals("seed: "+SEED, -1L, skipped);
+    }
+
+    @Test
+    public void testSkipFullyByteArray() throws IOException {
+        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        InputStream is = new FileInputStream(TMP);
+        IOUtils.copy(is, bos);
+        long skipped = IOUtils.skipFully(new ByteArrayInputStream(bos.toByteArray()), 20000L);
+        assertEquals("seed: "+SEED, -1L, skipped);
+    }
+
+    @Test
+    public void testSkipFullyByteArrayGtIntMax() throws IOException {
+        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        InputStream is = new FileInputStream(TMP);
+        IOUtils.copy(is, bos);
+        long skipped = IOUtils.skipFully(new ByteArrayInputStream(bos.toByteArray()), Integer.MAX_VALUE+ 20000L);
+        assertEquals("seed: "+SEED, -1L, skipped);
+    }
+
+    @Test
+    public void testWonkyInputStream() throws IOException {
+        long skipped = IOUtils.skipFully(new WonkyInputStream(), 10000);
+        assertEquals("seed: "+SEED, 10000, skipped);
+    }
+
+    /**
+     * This returns 0 for the first call to skip and then reads
+     * as requested.  This tests that the fallback to read() works.
+     */
+    private static class WonkyInputStream extends InputStream {
+        int skipCalled = 0;
+        int readCalled = 0;
+
+        @Override
+        public int read() throws IOException {
+            readCalled++;
+            return 0;
+        }
+
+        @Override
+        public int read(byte[] arr, int offset, int len) throws IOException {
+            readCalled++;
+            return len;
+        }
+
+        @Override
+        public long skip(long len) throws IOException {
+            skipCalled++;
+            if (skipCalled == 1) {
+                return 0;
+            } else if (skipCalled > 100) {
+                return len;
+            } else {
+                return 100;
+            }
+        }
+
+        @Override
+        public int available() {
+            return 100000;
+        }
+    }
+}