[COMPRESS-633] Add encryption support for SevenZ

.gitignore

@@ -3,6 +3,7 @@ target
 .classpath
 .settings
 .idea
+.vscode
 *.iml
 *~
 /.externalToolBuilders/

src/main/java/org/apache/commons/compress/archivers/sevenz/AES256Options.java

@@ -0,0 +1,100 @@
+/*
+ *  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.commons.compress.archivers.sevenz;
+
+import java.security.GeneralSecurityException;
+import java.security.NoSuchAlgorithmException;
+import java.security.SecureRandom;
+import javax.crypto.Cipher;
+import javax.crypto.SecretKey;
+import javax.crypto.spec.IvParameterSpec;
+import javax.crypto.spec.SecretKeySpec;
+
+/**
+ * Options for {@link SevenZMethod#AES256SHA256} encoder
+ * 
+ * @since 1.23
+ * @see AES256SHA256Decoder
+ */
+class AES256Options {
+
+    private final byte[] salt;
+    private final byte[] iv;
+    private final int numCyclesPower;
+    private final Cipher cipher;
+
+    /**
+     * @param password password used for encryption
+     */
+    public AES256Options(char[] password) {
+        this(password, new byte[0], randomBytes(16), 19);
+    }
+
+    /**
+     * @param password password used for encryption
+     * @param salt for password hash salting (enforce password security)
+     * @param iv Initialization Vector (IV) used by cipher algorithm
+     * @param numCyclesPower another password security enforcer parameter that controls the cycles of password hashing. More the
+     *                       this number is high, more security you'll have but also high CPU usage
+     */
+    public AES256Options(char[] password, byte[] salt, byte[] iv, int numCyclesPower) {
+        this.salt = salt;
+        this.iv = iv;
+        this.numCyclesPower = numCyclesPower;
+
+        // NOTE: for security purposes, password is wrapped in a Cipher as soon as possible to not stay in memory
+        final byte[] aesKeyBytes = AES256SHA256Decoder.sha256Password(password, numCyclesPower, salt);
+        final SecretKey aesKey = new SecretKeySpec(aesKeyBytes, "AES");
+
+        try {
+            cipher = Cipher.getInstance("AES/CBC/NoPadding");
+            cipher.init(Cipher.ENCRYPT_MODE, aesKey, new IvParameterSpec(iv));
+        } catch (final GeneralSecurityException generalSecurityException) {
+            throw new IllegalStateException(
+                "Encryption error (do you have the JCE Unlimited Strength Jurisdiction Policy Files installed?)",
+                generalSecurityException
+            );
+        }
+    }
+
+    byte[] getIv() {
+        return iv;
+    }
+
+    int getNumCyclesPower() {
+        return numCyclesPower;
+    }
+
+    byte[] getSalt() {
+        return salt;
+    }
+
+    Cipher getCipher() {
+        return cipher;
+    }
+
+    private static byte[] randomBytes(int size) {
+        byte[] bytes = new byte[size];
+        try {
+            SecureRandom.getInstanceStrong().nextBytes(bytes);
+        } catch (NoSuchAlgorithmException e) {
+            throw new IllegalStateException("No strong secure random available to generate strong AES key", e);
+        }
+        return bytes;
+    }
+}

src/main/java/org/apache/commons/compress/archivers/sevenz/AES256SHA256Decoder.java

@@ -17,21 +17,32 @@
  */
 package org.apache.commons.compress.archivers.sevenz;
 
+import static java.nio.charset.StandardCharsets.UTF_16LE;
+
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.OutputStream;
+import java.nio.ByteBuffer;
+import java.nio.CharBuffer;
 import java.security.GeneralSecurityException;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
+import java.util.Arrays;
 
 import javax.crypto.Cipher;
 import javax.crypto.CipherInputStream;
+import javax.crypto.CipherOutputStream;
 import javax.crypto.SecretKey;
 import javax.crypto.spec.IvParameterSpec;
 import javax.crypto.spec.SecretKeySpec;
 
 import org.apache.commons.compress.PasswordRequiredException;
 
 class AES256SHA256Decoder extends AbstractCoder {
+
+    AES256SHA256Decoder() {
+        super(AES256Options.class);
+    }
 
     @Override
     InputStream decode(final String archiveName, final InputStream in, final long uncompressedLength,
@@ -73,26 +84,7 @@ private CipherInputStream init() throws IOException {
                     System.arraycopy(passwordBytes, 0, aesKeyBytes, saltSize,
                                      Math.min(passwordBytes.length, aesKeyBytes.length - saltSize));
                 } else {
-                    final MessageDigest digest;
-                    try {
-                        digest = MessageDigest.getInstance("SHA-256");
-                    } catch (final NoSuchAlgorithmException noSuchAlgorithmException) {
-                        throw new IOException("SHA-256 is unsupported by your Java implementation",
-                            noSuchAlgorithmException);
-                    }
-                    final byte[] extra = new byte[8];
-                    for (long j = 0; j < (1L << numCyclesPower); j++) {
-                        digest.update(salt);
-                        digest.update(passwordBytes);
-                        digest.update(extra);
-                        for (int k = 0; k < extra.length; k++) {
-                            ++extra[k];
-                            if (extra[k] != 0) {
-                                break;
-                            }
-                        }
-                    }
-                    aesKeyBytes = digest.digest();
+                    aesKeyBytes = sha256Password(passwordBytes, numCyclesPower, salt);
                 }
 
                 final SecretKey aesKey = new SecretKeySpec(aesKeyBytes, "AES");
@@ -103,8 +95,8 @@ private CipherInputStream init() throws IOException {
                     isInitialized = true;
                     return cipherInputStream;
                 } catch (final GeneralSecurityException generalSecurityException) {
-                    throw new IOException("Decryption error " +
-                        "(do you have the JCE Unlimited Strength Jurisdiction Policy Files installed?)",
+                    throw new IllegalStateException(
+                        "Decryption error (do you have the JCE Unlimited Strength Jurisdiction Policy Files installed?)",
                         generalSecurityException);
                     }
             }
@@ -127,4 +119,133 @@ public void close() throws IOException {
             }
         };
     }
+
+    @Override
+    OutputStream encode(OutputStream out, Object options) throws IOException {
+        final AES256Options opts = (AES256Options) options;
+
+        return new OutputStream() {
+            private final CipherOutputStream cipherOutputStream = new CipherOutputStream(out, opts.getCipher());
+
+            // Ensures that data are encrypt in respect of cipher block size and pad with '0' if smaller
+            // NOTE: As "AES/CBC/PKCS5Padding" is weak and should not be used, we use "AES/CBC/NoPadding" with this
+            // manual implementation for padding possible thanks to the size of the file stored separately
+            private final int cipherBlockSize = opts.getCipher().getBlockSize();
+            private final byte[] cipherBlockBuffer = new byte[cipherBlockSize];
+            private int count = 0;
+
+            @Override
+            public void write(int b) throws IOException {
+                cipherBlockBuffer[count++] = (byte) b;
+                if (count == cipherBlockSize) {
+                    flushBuffer();
+                }
+            }
+
+            @Override
+            public void write(byte[] b, int off, int len) throws IOException {
+                int gap = len + count > cipherBlockSize ? cipherBlockSize - count : len;
+                System.arraycopy(b, off, cipherBlockBuffer, count, gap);
+                count += gap;
+
+                if (count == cipherBlockSize) {
+                    flushBuffer();
+
+                    if (len - gap >= cipherBlockSize) {
+                        // skip buffer to encrypt data chunks big enought to fit cipher block size
+                        int multipleCipherBlockSizeLen = (len - gap) / cipherBlockSize * cipherBlockSize;
+                        cipherOutputStream.write(b, off + gap, multipleCipherBlockSizeLen);
+                        gap += multipleCipherBlockSizeLen;
+                    }
+                    System.arraycopy(b, off + gap, cipherBlockBuffer, 0, len - gap);
+                    count = len - gap;
+                }
+            }
+
+            private void flushBuffer() throws IOException {
+                cipherOutputStream.write(cipherBlockBuffer);
+                count = 0;
+                Arrays.fill(cipherBlockBuffer, (byte) 0);
+            }
+
+            @Override
+            public void flush() throws IOException {
+                cipherOutputStream.flush();
+            }
+
+            @Override
+            public void close() throws IOException {
+                if (count > 0) {
+                    cipherOutputStream.write(cipherBlockBuffer);
+                }
+                cipherOutputStream.close();
+            }
+        };
+    }
+
+    @Override
+    byte[] getOptionsAsProperties(Object options) throws IOException {
+        final AES256Options opts = (AES256Options) options;
+        final byte[] props = new byte[2 + opts.getSalt().length + opts.getIv().length];
+
+        // First byte : control (numCyclesPower + flags of salt or iv presence)
+        props[0] = (byte) (opts.getNumCyclesPower() | (opts.getSalt().length == 0 ? 0 : (1 << 7)) | (opts.getIv().length == 0 ? 0 : (1 << 6)));
+
+        if (opts.getSalt().length != 0 || opts.getIv().length != 0) {
+            // second byte : size of salt/iv data
+            props[1] = (byte) (((opts.getSalt().length == 0 ? 0 : opts.getSalt().length - 1) << 4) | (opts.getIv().length == 0 ? 0 : opts.getIv().length - 1));
+
+            // remain bytes : salt/iv data
+            System.arraycopy(opts.getSalt(), 0, props, 2, opts.getSalt().length);
+            System.arraycopy(opts.getIv(), 0, props, 2 + opts.getSalt().length, opts.getIv().length);
+        }
+
+        return props;
+    }
+
+    static byte[] sha256Password(final char[] password, final int numCyclesPower, final byte[] salt) {
+        return sha256Password(utf16Decode(password), numCyclesPower, salt);
+    }
+
+    static byte[] sha256Password(final byte[] password, final int numCyclesPower, final byte[] salt) {
+        final MessageDigest digest;
+        try {
+            digest = MessageDigest.getInstance("SHA-256");
+        } catch (final NoSuchAlgorithmException noSuchAlgorithmException) {
+            throw new IllegalStateException("SHA-256 is unsupported by your Java implementation", noSuchAlgorithmException);
+        }
+        final byte[] extra = new byte[8];
+        for (long j = 0; j < (1L << numCyclesPower); j++) {
+            digest.update(salt);
+            digest.update(password);
+            digest.update(extra);
+            for (int k = 0; k < extra.length; k++) {
+                ++extra[k];
+                if (extra[k] != 0) {
+                    break;
+                }
+            }
+        }
+        return digest.digest();
+    }
+
+    /**
+     * Convenience method that encodes Unicode characters into bytes in UTF-16 (ittle-endian byte order) charset
+     *
+     * @param chars characters to encode
+     * @return encoded characters
+     * @since 1.23
+     */
+    static byte[] utf16Decode(final char[] chars) {
+        if (chars == null) {
+            return null;
+        }
+        final ByteBuffer encoded = UTF_16LE.encode(CharBuffer.wrap(chars));
+        if (encoded.hasArray()) {
+            return encoded.array();
+        }
+        final byte[] e = new byte[encoded.remaining()];
+        encoded.get(e);
+        return e;
+    }
 }

src/main/java/org/apache/commons/compress/archivers/sevenz/SevenZFile.java

@@ -30,7 +30,6 @@
 import java.io.InputStream;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
-import java.nio.CharBuffer;
 import java.nio.channels.Channels;
 import java.nio.channels.SeekableByteChannel;
 import java.nio.file.Files;
@@ -137,7 +136,7 @@ public SevenZFile(final File fileName, final char[] password) throws IOException
      */
     public SevenZFile(final File fileName, final char[] password, final SevenZFileOptions options) throws IOException {
         this(Files.newByteChannel(fileName.toPath(), EnumSet.of(StandardOpenOption.READ)), // NOSONAR
-                fileName.getAbsolutePath(), utf16Decode(password), true, options);
+                fileName.getAbsolutePath(), AES256SHA256Decoder.utf16Decode(password), true, options);
     }
 
     /**
@@ -256,7 +255,7 @@ public SevenZFile(final SeekableByteChannel channel, final String fileName,
      */
     public SevenZFile(final SeekableByteChannel channel, final String fileName, final char[] password,
             final SevenZFileOptions options) throws IOException {
-        this(channel, fileName, utf16Decode(password), false, options);
+        this(channel, fileName, AES256SHA256Decoder.utf16Decode(password), false, options);
     }
 
     /**
@@ -2056,19 +2055,6 @@ public String getDefaultName() {
         return lastSegment + "~";
     }
 
-    private static byte[] utf16Decode(final char[] chars) {
-        if (chars == null) {
-            return null;
-        }
-        final ByteBuffer encoded = UTF_16LE.encode(CharBuffer.wrap(chars));
-        if (encoded.hasArray()) {
-            return encoded.array();
-        }
-        final byte[] e = new byte[encoded.remaining()];
-        encoded.get(e);
-        return e;
-    }
-
     private static int assertFitsIntoNonNegativeInt(final String what, final long value) throws IOException {
         if (value > Integer.MAX_VALUE || value < 0) {
             throw new IOException("Cannot handle " + what + " " + value);