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Merge "Redact ISOBMFF boxes with 'free'" into qt-dev

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This commit is contained in:
Andrew Lewis
2019-07-11 13:10:59 +00:00
committed by Android (Google) Code Review
parent 6c22dff644 4ec5fda3d6
commit f68a201ebc
2 changed files with 97 additions and 9 deletions
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26
core/java/android/os/RedactingFileDescriptor.java
View File

@@ -35,7 +35,7 @@ import java.util.Arrays;
/**
* Variant of {@link FileDescriptor} that allows its creator to specify regions
* that should be redacted (appearing as zeros to the reader).
* that should be redacted.
*
* @hide
*/
@@ -44,13 +44,16 @@ public class RedactingFileDescriptor {
private static final boolean DEBUG = true;
private volatile long[] mRedactRanges;
private volatile long[] mFreeOffsets;
private FileDescriptor mInner = null;
private ParcelFileDescriptor mOuter = null;
private RedactingFileDescriptor(Context context, File file, int mode, long[] redactRanges)
private RedactingFileDescriptor(
Context context, File file, int mode, long[] redactRanges, long[] freeOffsets)
throws IOException {
mRedactRanges = checkRangesArgument(redactRanges);
mFreeOffsets = freeOffsets;
try {
try {
@@ -88,13 +91,17 @@ public class RedactingFileDescriptor {
*
* @param file The underlying file to open.
* @param mode The {@link ParcelFileDescriptor} mode to open with.
* @param redactRanges List of file offsets that should be redacted, stored
* @param redactRanges List of file ranges that should be redacted, stored
* as {@code [start1, end1, start2, end2, ...]}. Start values are
* inclusive and end values are exclusive.
* @param freePositions List of file offsets at which the four byte value 'free' should be
* written instead of zeros within parts of the file covered by {@code redactRanges}.
* Non-redacted bytes will not be modified even if covered by a 'free'. This is
* useful for overwriting boxes in ISOBMFF files with padding data.
*/
public static ParcelFileDescriptor open(Context context, File file, int mode,
long[] redactRanges) throws IOException {
return new RedactingFileDescriptor(context, file, mode, redactRanges).mOuter;
long[] redactRanges, long[] freePositions) throws IOException {
return new RedactingFileDescriptor(context, file, mode, redactRanges, freePositions).mOuter;
}
/**
@@ -169,6 +176,15 @@ public class RedactingFileDescriptor {
for (long j = start; j < end; j++) {
data[(int) (j - offset)] = 0;
}
// Overwrite data at 'free' offsets within the redaction ranges.
for (long freeOffset : mFreeOffsets) {
final long freeEnd = freeOffset + 4;
final long redactFreeStart = Math.max(freeOffset, start);
final long redactFreeEnd = Math.min(freeEnd, end);
for (long j = redactFreeStart; j < redactFreeEnd; j++) {
data[(int) (j - offset)] = (byte) "free".charAt((int) (j - freeOffset));
}
}
}
return n;
}

80
core/tests/coretests/src/android/os/RedactingFileDescriptorTest.java
View File

@@ -64,7 +64,7 @@ public class RedactingFileDescriptorTest {
@Test
public void testSingleByte() throws Exception {
final FileDescriptor fd = RedactingFileDescriptor.open(mContext, mFile, MODE_READ_ONLY,
new long[] { 10, 11 }).getFileDescriptor();
new long[] { 10, 11 }, new long[] {}).getFileDescriptor();
final byte[] buf = new byte[1_000];
assertEquals(buf.length, Os.read(fd, buf, 0, buf.length));
@@ -80,7 +80,7 @@ public class RedactingFileDescriptorTest {
@Test
public void testRanges() throws Exception {
final FileDescriptor fd = RedactingFileDescriptor.open(mContext, mFile, MODE_READ_ONLY,
new long[] { 100, 200, 300, 400 }).getFileDescriptor();
new long[] { 100, 200, 300, 400 }, new long[] {}).getFileDescriptor();
final byte[] buf = new byte[10];
assertEquals(buf.length, Os.pread(fd, buf, 0, 10, 90));
@@ -102,7 +102,7 @@ public class RedactingFileDescriptorTest {
@Test
public void testEntireFile() throws Exception {
final FileDescriptor fd = RedactingFileDescriptor.open(mContext, mFile, MODE_READ_ONLY,
new long[] { 0, 5_000_000 }).getFileDescriptor();
new long[] { 0, 5_000_000 }, new long[] {}).getFileDescriptor();
try (FileInputStream in = new FileInputStream(fd)) {
int val;
@@ -115,7 +115,7 @@ public class RedactingFileDescriptorTest {
@Test
public void testReadWrite() throws Exception {
final FileDescriptor fd = RedactingFileDescriptor.open(mContext, mFile, MODE_READ_WRITE,
new long[] { 100, 200, 300, 400 }).getFileDescriptor();
new long[] { 100, 200, 300, 400 }, new long[] {}).getFileDescriptor();
// Redacted at first
final byte[] buf = new byte[10];
@@ -168,4 +168,76 @@ public class RedactingFileDescriptorTest {
assertArrayEquals(new long[] { 100, 200 },
removeRange(new long[] { 100, 200 }, 150, 150));
}
@Test
public void testFreeAtStart() throws Exception {
final FileDescriptor fd = RedactingFileDescriptor.open(mContext, mFile, MODE_READ_WRITE,
new long[] { 1, 10 }, new long[] {1}).getFileDescriptor();
final byte[] buf = new byte[10];
assertEquals(buf.length, Os.pread(fd, buf, 0, 10, 0));
assertArrayEquals(
new byte[] { 64, (byte) 'f', (byte) 'r', (byte) 'e', (byte) 'e', 0, 0, 0, 0, 0 },
buf);
}
@Test
public void testFreeAtOffset() throws Exception {
final FileDescriptor fd = RedactingFileDescriptor.open(mContext, mFile, MODE_READ_WRITE,
new long[] { 1, 10 }, new long[] {3}).getFileDescriptor();
final byte[] buf = new byte[10];
assertEquals(buf.length, Os.pread(fd, buf, 0, 10, 0));
assertArrayEquals(
new byte[] { 64, 0, 0, (byte) 'f', (byte) 'r', (byte) 'e', (byte) 'e', 0, 0, 0 },
buf);
}
@Test
public void testFreeAcrossRedactionStart() throws Exception {
final FileDescriptor fd = RedactingFileDescriptor.open(mContext, mFile, MODE_READ_WRITE,
new long[] { 1, 10 }, new long[] {0}).getFileDescriptor();
final byte[] buf = new byte[10];
assertEquals(buf.length, Os.pread(fd, buf, 0, 10, 0));
assertArrayEquals(
new byte[] { 64, (byte) 'r', (byte) 'e', (byte) 'e', 0, 0, 0, 0, 0, 0 },
buf);
}
@Test
public void testFreeAcrossRedactionEnd() throws Exception {
final FileDescriptor fd = RedactingFileDescriptor.open(mContext, mFile, MODE_READ_WRITE,
new long[] { 1, 3 }, new long[] {2}).getFileDescriptor();
final byte[] buf = new byte[10];
assertEquals(buf.length, Os.pread(fd, buf, 0, 10, 0));
assertArrayEquals(
new byte[] { 64, 0, (byte) 'f', 64, 64, 64, 64, 64, 64, 64 },
buf);
}
@Test
public void testFreeOutsideRedaction() throws Exception {
final FileDescriptor fd = RedactingFileDescriptor.open(mContext, mFile, MODE_READ_WRITE,
new long[] { 1, 8 }, new long[] { 8 }).getFileDescriptor();
final byte[] buf = new byte[10];
assertEquals(buf.length, Os.pread(fd, buf, 0, 10, 0));
assertArrayEquals(
new byte[] { 64, 0, 0, 0, 0, 0, 0, 0, 64, 64 },
buf);
}
@Test
public void testFreeMultipleRedactions() throws Exception {
final FileDescriptor fd = RedactingFileDescriptor.open(mContext, mFile, MODE_READ_WRITE,
new long[] { 1, 2, 3, 4 }, new long[] { 0 }).getFileDescriptor();
final byte[] buf = new byte[10];
assertEquals(buf.length, Os.pread(fd, buf, 0, 10, 0));
assertArrayEquals(
new byte[] { 64, (byte) 'r', 64, (byte) 'e', 64, 64, 64, 64, 64, 64 },
buf);
}
}