HADOOP-19197. S3A: Support AWS KMS Encryption Context (#6874)

The new property fs.s3a.encryption.context allow users to specify the AWS KMS Encryption Context to be used in S3A.

The value of the encryption context is a key/value string that will be Base64 encoded and set in the parameter ssekmsEncryptionContext from the S3 client.

Contributed by Raphael Azzolini

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/CommonConfigurationKeysPublic.java

@@ -1022,6 +1022,7 @@ public class CommonConfigurationKeysPublic {
           "fs.s3a.*.server-side-encryption.key",
           "fs.s3a.encryption.algorithm",
           "fs.s3a.encryption.key",
+          "fs.s3a.encryption.context",
           "fs.azure\\.account.key.*",
           "credential$",
           "oauth.*secret",

hadoop-common-project/hadoop-common/src/main/resources/core-default.xml

@@ -742,6 +742,7 @@
       fs.s3a.*.server-side-encryption.key
       fs.s3a.encryption.algorithm
       fs.s3a.encryption.key
+      fs.s3a.encryption.context
       fs.s3a.secret.key
       fs.s3a.*.secret.key
       fs.s3a.session.key
@@ -1760,6 +1761,15 @@
   </description>
 </property>
 
+<property>
+  <name>fs.s3a.encryption.context</name>
+  <description>Specific encryption context to use if fs.s3a.encryption.algorithm
+    has been set to 'SSE-KMS' or 'DSSE-KMS'. The value of this property is a set
+    of non-secret comma-separated key-value pairs of additional contextual
+    information about the data that are separated by equal operator (=).
+  </description>
+</property>
+
 <property>
   <name>fs.s3a.signing-algorithm</name>
   <description>Override the default signing algorithm so legacy

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/Constants.java

@@ -736,6 +736,16 @@ private Constants() {
   public static final String S3_ENCRYPTION_KEY =
       "fs.s3a.encryption.key";
 
+  /**
+   * Set S3-SSE encryption context.
+   * The value of this property is a set of non-secret comma-separated key-value pairs
+   * of additional contextual information about the data that are separated by equal
+   * operator (=).
+   * value:{@value}
+   */
+  public static final String S3_ENCRYPTION_CONTEXT =
+      "fs.s3a.encryption.context";
+
   /**
    * List of custom Signers. The signer class will be loaded, and the signer
    * name will be associated with this signer class in the S3 SDK.

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/S3AUtils.java

@@ -37,6 +37,7 @@
 import org.apache.hadoop.fs.PathFilter;
 import org.apache.hadoop.fs.PathIOException;
 import org.apache.hadoop.fs.RemoteIterator;
+import org.apache.hadoop.fs.s3a.impl.S3AEncryption;
 import org.apache.hadoop.util.functional.RemoteIterators;
 import org.apache.hadoop.fs.s3a.auth.delegation.EncryptionSecrets;
 import org.apache.hadoop.fs.s3a.impl.MultiObjectDeleteException;
@@ -1312,7 +1313,7 @@ static void patchSecurityCredentialProviders(Configuration conf) {
    * @throws IOException on any IO problem
    * @throws IllegalArgumentException bad arguments
    */
-  private static String lookupBucketSecret(
+  public static String lookupBucketSecret(
       String bucket,
       Configuration conf,
       String baseKey)
@@ -1458,6 +1459,8 @@ public static EncryptionSecrets buildEncryptionSecrets(String bucket,
     int encryptionKeyLen =
         StringUtils.isBlank(encryptionKey) ? 0 : encryptionKey.length();
     String diagnostics = passwordDiagnostics(encryptionKey, "key");
+    String encryptionContext = S3AEncryption.getS3EncryptionContextBase64Encoded(bucket, conf,
+        encryptionMethod.requiresSecret());
     switch (encryptionMethod) {
     case SSE_C:
       LOG.debug("Using SSE-C with {}", diagnostics);
@@ -1493,7 +1496,7 @@ public static EncryptionSecrets buildEncryptionSecrets(String bucket,
       LOG.debug("Data is unencrypted");
       break;
     }
-    return new EncryptionSecrets(encryptionMethod, encryptionKey);
+    return new EncryptionSecrets(encryptionMethod, encryptionKey, encryptionContext);
   }
 
   /**
@@ -1686,6 +1689,21 @@ public static Map<String, String> getTrimmedStringCollectionSplitByEquals(
       final Configuration configuration,
       final String name) {
     String valueString = configuration.get(name);
+    return getTrimmedStringCollectionSplitByEquals(valueString);
+  }
+
+  /**
+   * Get the equal op (=) delimited key-value pairs of the <code>name</code> property as
+   * a collection of pair of <code>String</code>s, trimmed of the leading and trailing whitespace
+   * after delimiting the <code>name</code> by comma and new line separator.
+   * If no such property is specified then empty <code>Map</code> is returned.
+   *
+   * @param valueString the string containing the key-value pairs.
+   * @return property value as a <code>Map</code> of <code>String</code>s, or empty
+   * <code>Map</code>.
+   */
+  public static Map<String, String> getTrimmedStringCollectionSplitByEquals(
+      final String valueString) {
     if (null == valueString) {
       return new HashMap<>();
     }

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/auth/delegation/EncryptionSecretOperations.java

@@ -61,4 +61,20 @@ public static Optional<String> getSSEAwsKMSKey(final EncryptionSecrets secrets)
       return Optional.empty();
     }
   }
+
+  /**
+   * Gets the SSE-KMS context if present, else don't set it in the S3 request.
+   *
+   * @param secrets source of the encryption secrets.
+   * @return an optional AWS KMS encryption context to attach to a request.
+   */
+  public static Optional<String> getSSEAwsKMSEncryptionContext(final EncryptionSecrets secrets) {
+    if ((secrets.getEncryptionMethod() == S3AEncryptionMethods.SSE_KMS
+        || secrets.getEncryptionMethod() == S3AEncryptionMethods.DSSE_KMS)
+        && secrets.hasEncryptionContext()) {
+      return Optional.of(secrets.getEncryptionContext());
+    } else {
+      return Optional.empty();
+    }
+  }
 }

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/auth/delegation/EncryptionSecrets.java

@@ -67,6 +67,11 @@ public class EncryptionSecrets implements Writable, Serializable {
    */
   private String encryptionKey = "";
 
+  /**
+   * Encryption context: base64-encoded UTF-8 string.
+   */
+  private String encryptionContext = "";
+
   /**
    * This field isn't serialized/marshalled; it is rebuilt from the
    * encryptionAlgorithm field.
@@ -84,23 +89,28 @@ public EncryptionSecrets() {
    * Create a pair of secrets.
    * @param encryptionAlgorithm algorithm enumeration.
    * @param encryptionKey key/key reference.
+   * @param encryptionContext  base64-encoded string with the encryption context key-value pairs.
    * @throws IOException failure to initialize.
    */
   public EncryptionSecrets(final S3AEncryptionMethods encryptionAlgorithm,
-      final String encryptionKey) throws IOException {
-    this(encryptionAlgorithm.getMethod(), encryptionKey);
+      final String encryptionKey,
+      final String encryptionContext) throws IOException {
+    this(encryptionAlgorithm.getMethod(), encryptionKey, encryptionContext);
   }
 
   /**
    * Create a pair of secrets.
    * @param encryptionAlgorithm algorithm name
    * @param encryptionKey key/key reference.
+   * @param encryptionContext  base64-encoded string with the encryption context key-value pairs.
    * @throws IOException failure to initialize.
    */
   public EncryptionSecrets(final String encryptionAlgorithm,
-      final String encryptionKey) throws IOException {
+      final String encryptionKey,
+      final String encryptionContext) throws IOException {
     this.encryptionAlgorithm = encryptionAlgorithm;
     this.encryptionKey = encryptionKey;
+    this.encryptionContext = encryptionContext;
     init();
   }
 
@@ -114,6 +124,7 @@ public void write(final DataOutput out) throws IOException {
     new LongWritable(serialVersionUID).write(out);
     Text.writeString(out, encryptionAlgorithm);
     Text.writeString(out, encryptionKey);
+    Text.writeString(out, encryptionContext);
   }
 
   /**
@@ -132,6 +143,7 @@ public void readFields(final DataInput in) throws IOException {
     }
     encryptionAlgorithm = Text.readString(in, MAX_SECRET_LENGTH);
     encryptionKey = Text.readString(in, MAX_SECRET_LENGTH);
+    encryptionContext = Text.readString(in);
     init();
   }
 
@@ -164,6 +176,10 @@ public String getEncryptionKey() {
     return encryptionKey;
   }
 
+  public String getEncryptionContext() {
+    return encryptionContext;
+  }
+
   /**
    * Does this instance have encryption options?
    * That is: is the algorithm non-null.
@@ -181,6 +197,14 @@ public boolean hasEncryptionKey() {
     return StringUtils.isNotEmpty(encryptionKey);
   }
 
+  /**
+   * Does this instance have an encryption context?
+   * @return true if there's an encryption context.
+   */
+  public boolean hasEncryptionContext() {
+    return StringUtils.isNotEmpty(encryptionContext);
+  }
+
   @Override
   public boolean equals(final Object o) {
     if (this == o) {
@@ -191,12 +215,13 @@ public boolean equals(final Object o) {
     }
     final EncryptionSecrets that = (EncryptionSecrets) o;
     return Objects.equals(encryptionAlgorithm, that.encryptionAlgorithm)
-        && Objects.equals(encryptionKey, that.encryptionKey);
+        && Objects.equals(encryptionKey, that.encryptionKey)
+        && Objects.equals(encryptionContext, that.encryptionContext);
   }
 
   @Override
   public int hashCode() {
-    return Objects.hash(encryptionAlgorithm, encryptionKey);
+    return Objects.hash(encryptionAlgorithm, encryptionKey, encryptionContext);
   }
 
   /**

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/impl/RequestFactoryImpl.java

@@ -270,6 +270,8 @@ protected void copyEncryptionParameters(HeadObjectResponse srcom,
       LOG.debug("Propagating SSE-KMS settings from source {}",
           sourceKMSId);
       copyObjectRequestBuilder.ssekmsKeyId(sourceKMSId);
+      EncryptionSecretOperations.getSSEAwsKMSEncryptionContext(encryptionSecrets)
+          .ifPresent(copyObjectRequestBuilder::ssekmsEncryptionContext);
       return;
     }
 
@@ -282,11 +284,15 @@ protected void copyEncryptionParameters(HeadObjectResponse srcom,
       // Set the KMS key if present, else S3 uses AWS managed key.
       EncryptionSecretOperations.getSSEAwsKMSKey(encryptionSecrets)
           .ifPresent(copyObjectRequestBuilder::ssekmsKeyId);
+      EncryptionSecretOperations.getSSEAwsKMSEncryptionContext(encryptionSecrets)
+              .ifPresent(copyObjectRequestBuilder::ssekmsEncryptionContext);
       break;
     case DSSE_KMS:
       copyObjectRequestBuilder.serverSideEncryption(ServerSideEncryption.AWS_KMS_DSSE);
       EncryptionSecretOperations.getSSEAwsKMSKey(encryptionSecrets)
           .ifPresent(copyObjectRequestBuilder::ssekmsKeyId);
+      EncryptionSecretOperations.getSSEAwsKMSEncryptionContext(encryptionSecrets)
+              .ifPresent(copyObjectRequestBuilder::ssekmsEncryptionContext);
       break;
     case SSE_C:
       EncryptionSecretOperations.getSSECustomerKey(encryptionSecrets)
@@ -371,11 +377,15 @@ private void putEncryptionParameters(PutObjectRequest.Builder putObjectRequestBu
       // Set the KMS key if present, else S3 uses AWS managed key.
       EncryptionSecretOperations.getSSEAwsKMSKey(encryptionSecrets)
           .ifPresent(putObjectRequestBuilder::ssekmsKeyId);
+      EncryptionSecretOperations.getSSEAwsKMSEncryptionContext(encryptionSecrets)
+              .ifPresent(putObjectRequestBuilder::ssekmsEncryptionContext);
       break;
     case DSSE_KMS:
       putObjectRequestBuilder.serverSideEncryption(ServerSideEncryption.AWS_KMS_DSSE);
       EncryptionSecretOperations.getSSEAwsKMSKey(encryptionSecrets)
           .ifPresent(putObjectRequestBuilder::ssekmsKeyId);
+      EncryptionSecretOperations.getSSEAwsKMSEncryptionContext(encryptionSecrets)
+              .ifPresent(putObjectRequestBuilder::ssekmsEncryptionContext);
       break;
     case SSE_C:
       EncryptionSecretOperations.getSSECustomerKey(encryptionSecrets)
@@ -447,11 +457,15 @@ private void multipartUploadEncryptionParameters(
       // Set the KMS key if present, else S3 uses AWS managed key.
       EncryptionSecretOperations.getSSEAwsKMSKey(encryptionSecrets)
           .ifPresent(mpuRequestBuilder::ssekmsKeyId);
+      EncryptionSecretOperations.getSSEAwsKMSEncryptionContext(encryptionSecrets)
+              .ifPresent(mpuRequestBuilder::ssekmsEncryptionContext);
       break;
     case DSSE_KMS:
       mpuRequestBuilder.serverSideEncryption(ServerSideEncryption.AWS_KMS_DSSE);
       EncryptionSecretOperations.getSSEAwsKMSKey(encryptionSecrets)
           .ifPresent(mpuRequestBuilder::ssekmsKeyId);
+      EncryptionSecretOperations.getSSEAwsKMSEncryptionContext(encryptionSecrets)
+              .ifPresent(mpuRequestBuilder::ssekmsEncryptionContext);
       break;
     case SSE_C:
       EncryptionSecretOperations.getSSECustomerKey(encryptionSecrets)

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/impl/S3AEncryption.java

@@ -0,0 +1,106 @@
+/*
+ * 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.hadoop.fs.s3a.impl;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.Map;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import org.apache.commons.codec.binary.Base64;
+import org.apache.commons.lang3.StringUtils;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.s3a.S3AUtils;
+
+import static org.apache.hadoop.fs.s3a.Constants.S3_ENCRYPTION_CONTEXT;
+
+/**
+ * Utility methods for S3A encryption properties.
+ */
+public final class S3AEncryption {
+
+  private static final Logger LOG = LoggerFactory.getLogger(S3AEncryption.class);
+
+  private S3AEncryption() {
+  }
+
+  /**
+   * Get any SSE context from a configuration/credential provider.
+   * @param bucket bucket to query for
+   * @param conf configuration to examine
+   * @return the encryption context value or ""
+   * @throws IOException if reading a JCEKS file raised an IOE
+   * @throws IllegalArgumentException bad arguments.
+   */
+  public static String getS3EncryptionContext(String bucket, Configuration conf)
+      throws IOException {
+    // look up the per-bucket value of the encryption context
+    String encryptionContext = S3AUtils.lookupBucketSecret(bucket, conf, S3_ENCRYPTION_CONTEXT);
+    if (encryptionContext == null) {
+      // look up the global value of the encryption context
+      encryptionContext = S3AUtils.lookupPassword(null, conf, S3_ENCRYPTION_CONTEXT);
+    }
+    if (encryptionContext == null) {
+      // no encryption context, return ""
+      return "";
+    }
+    return encryptionContext;
+  }
+
+  /**
+   * Get any SSE context from a configuration/credential provider.
+   * This includes converting the values to a base64-encoded UTF-8 string
+   * holding JSON with the encryption context key-value pairs
+   * @param bucket bucket to query for
+   * @param conf configuration to examine
+   * @param propagateExceptions should IO exceptions be rethrown?
+   * @return the Base64 encryption context or ""
+   * @throws IllegalArgumentException bad arguments.
+   * @throws IOException if propagateExceptions==true and reading a JCEKS file raised an IOE
+   */
+  public static String getS3EncryptionContextBase64Encoded(
+      String bucket,
+      Configuration conf,
+      boolean propagateExceptions) throws IOException {
+    try {
+      final String encryptionContextValue = getS3EncryptionContext(bucket, conf);
+      if (StringUtils.isBlank(encryptionContextValue)) {
+        return "";
+      }
+      final Map<String, String> encryptionContextMap = S3AUtils
+          .getTrimmedStringCollectionSplitByEquals(encryptionContextValue);
+      if (encryptionContextMap.isEmpty()) {
+        return "";
+      }
+      final String encryptionContextJson = new ObjectMapper().writeValueAsString(
+          encryptionContextMap);
+      return Base64.encodeBase64String(encryptionContextJson.getBytes(StandardCharsets.UTF_8));
+    } catch (IOException e) {
+      if (propagateExceptions) {
+        throw e;
+      }
+      LOG.warn("Cannot retrieve {} for bucket {}",
+          S3_ENCRYPTION_CONTEXT, bucket, e);
+      return "";
+    }
+  }
+}

hadoop-tools/hadoop-aws/src/site/markdown/tools/hadoop-aws/encryption.md

@@ -243,6 +243,21 @@ The ID of the specific key used to encrypt the data should also be set in the pr
 </property>
 ```
 
+Optionally, you can specify the encryption context in the property `fs.s3a.encryption.context`:
+
+```xml
+<property>
+  <name>fs.s3a.encryption.context</name>
+    <value>
+        key1=value1,
+        key2=value2,
+        key3=value3,
+        key4=value4,
+        key5=value5
+    </value>
+</property>
+```
+
 Organizations may define a default key in the Amazon KMS; if a default key is set,
 then it will be used whenever SSE-KMS encryption is chosen and the value of `fs.s3a.encryption.key` is empty.
 
@@ -378,6 +393,21 @@ The ID of the specific key used to encrypt the data should also be set in the pr
 </property>
 ```
 
+Optionally, you can specify the encryption context in the property `fs.s3a.encryption.context`:
+
+```xml
+<property>
+  <name>fs.s3a.encryption.context</name>
+    <value>
+        key1=value1,
+        key2=value2,
+        key3=value3,
+        key4=value4,
+        key5=value5
+    </value>
+</property>
+```
+
 Organizations may define a default key in the Amazon KMS; if a default key is set,
 then it will be used whenever SSE-KMS encryption is chosen and the value of `fs.s3a.encryption.key` is empty.
 

hadoop-tools/hadoop-aws/src/site/markdown/tools/hadoop-aws/index.md

@@ -625,6 +625,15 @@ Here are some the S3A properties for use in production.
   </description>
 </property>
 
+<property>
+    <name>fs.s3a.encryption.context</name>
+    <description>Specific encryption context to use if fs.s3a.encryption.algorithm
+      has been set to 'SSE-KMS' or 'DSSE-KMS'. The value of this property is a set
+      of non-secret comma-separated key-value pairs of additional contextual
+      information about the data that are separated by equal operator (=).
+    </description>
+</property>
+
 <property>
   <name>fs.s3a.signing-algorithm</name>
   <description>Override the default signing algorithm so legacy
@@ -1294,6 +1303,11 @@ For a site configuration of:
   <value>unset</value>
 </property>
 
+<property>
+  <name>fs.s3a.encryption.context</name>
+  <value>unset</value>
+</property>
+
 
 ```
 

hadoop-tools/hadoop-aws/src/test/java/org/apache/hadoop/fs/s3a/AbstractTestS3AEncryption.java

@@ -30,6 +30,7 @@
 
 import static org.apache.hadoop.fs.contract.ContractTestUtils.*;
 import static org.apache.hadoop.fs.s3a.Constants.S3_ENCRYPTION_ALGORITHM;
+import static org.apache.hadoop.fs.s3a.Constants.S3_ENCRYPTION_CONTEXT;
 import static org.apache.hadoop.fs.s3a.Constants.S3_ENCRYPTION_KEY;
 import static org.apache.hadoop.fs.s3a.Constants.SERVER_SIDE_ENCRYPTION_ALGORITHM;
 import static org.apache.hadoop.fs.s3a.Constants.SERVER_SIDE_ENCRYPTION_KEY;
@@ -69,6 +70,7 @@ protected void patchConfigurationEncryptionSettings(
     removeBaseAndBucketOverrides(conf,
         S3_ENCRYPTION_ALGORITHM,
         S3_ENCRYPTION_KEY,
+        S3_ENCRYPTION_CONTEXT,
         SERVER_SIDE_ENCRYPTION_ALGORITHM,
         SERVER_SIDE_ENCRYPTION_KEY);
     conf.set(S3_ENCRYPTION_ALGORITHM,

hadoop-tools/hadoop-aws/src/test/java/org/apache/hadoop/fs/s3a/ITestS3AEncryptionSSEKMSWithEncryptionContext.java

@@ -0,0 +1,101 @@
+/**
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.hadoop.fs.s3a;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.util.Set;
+
+import org.apache.hadoop.thirdparty.com.google.common.collect.ImmutableSet;
+
+import org.apache.commons.lang.StringUtils;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.s3a.impl.S3AEncryption;
+
+import static org.apache.hadoop.fs.contract.ContractTestUtils.skip;
+import static org.apache.hadoop.fs.s3a.Constants.S3_ENCRYPTION_CONTEXT;
+import static org.apache.hadoop.fs.s3a.Constants.S3_ENCRYPTION_KEY;
+import static org.apache.hadoop.fs.s3a.S3AEncryptionMethods.DSSE_KMS;
+import static org.apache.hadoop.fs.s3a.S3AEncryptionMethods.SSE_KMS;
+import static org.apache.hadoop.fs.s3a.S3ATestUtils.assume;
+import static org.apache.hadoop.fs.s3a.S3ATestUtils.getTestBucketName;
+
+/**
+ * Concrete class that extends {@link AbstractTestS3AEncryption}
+ * and tests KMS encryption with encryption context.
+ * S3's HeadObject doesn't return the object's encryption context.
+ * Therefore, we don't have a way to assert its value in code.
+ * In order to properly test if the encryption context is being set,
+ * the KMS key or the IAM User need to have a deny statements like the one below in the policy:
+ * <pre>
+ * {
+ *     "Effect": "Deny",
+ *     "Principal": {
+ *         "AWS": "*"
+ *     },
+ *     "Action": "kms:Decrypt",
+ *     "Resource": "*",
+ *     "Condition": {
+ *         "StringNotEquals": {
+ *             "kms:EncryptionContext:project": "hadoop"
+ *         }
+ *     }
+ * }
+ * </pre>
+ * With the statement above, S3A will fail to read the object from S3 if it was encrypted
+ * without the key-pair <code>"project": "hadoop"</code> in the encryption context.
+ */
+public class ITestS3AEncryptionSSEKMSWithEncryptionContext
+    extends AbstractTestS3AEncryption {
+
+  private static final Set<S3AEncryptionMethods> KMS_ENCRYPTION_ALGORITHMS = ImmutableSet.of(
+      SSE_KMS, DSSE_KMS);
+
+  private S3AEncryptionMethods encryptionAlgorithm;
+
+  @Override
+  protected Configuration createConfiguration() {
+    try {
+      // get the KMS key and context for this test.
+      Configuration c = new Configuration();
+      final String bucketName = getTestBucketName(c);
+      String kmsKey = S3AUtils.getS3EncryptionKey(bucketName, c);
+      String encryptionContext = S3AEncryption.getS3EncryptionContext(bucketName, c);
+      encryptionAlgorithm = S3AUtils.getEncryptionAlgorithm(bucketName, c);
+      assume("Expected a KMS encryption algorithm",
+          KMS_ENCRYPTION_ALGORITHMS.contains(encryptionAlgorithm));
+      if (StringUtils.isBlank(encryptionContext)) {
+        skip(S3_ENCRYPTION_CONTEXT + " is not set.");
+      }
+      Configuration conf = super.createConfiguration();
+      S3ATestUtils.removeBaseAndBucketOverrides(conf, S3_ENCRYPTION_KEY, S3_ENCRYPTION_CONTEXT);
+      conf.set(S3_ENCRYPTION_KEY, kmsKey);
+      conf.set(S3_ENCRYPTION_CONTEXT, encryptionContext);
+      return conf;
+
+    } catch (IOException e) {
+      throw new UncheckedIOException(e);
+    }
+  }
+
+  @Override
+  protected S3AEncryptionMethods getSSEAlgorithm() {
+    return encryptionAlgorithm;
+  }
+}

hadoop-tools/hadoop-aws/src/test/java/org/apache/hadoop/fs/s3a/TestSSEConfiguration.java

@@ -29,9 +29,11 @@
 import org.junit.rules.Timeout;
 
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.s3a.impl.S3AEncryption;
 import org.apache.hadoop.security.ProviderUtils;
 import org.apache.hadoop.security.alias.CredentialProvider;
 import org.apache.hadoop.security.alias.CredentialProviderFactory;
+import org.apache.hadoop.util.StringUtils;
 
 import static org.apache.hadoop.fs.s3a.Constants.*;
 import static org.apache.hadoop.fs.s3a.S3AEncryptionMethods.*;
@@ -48,6 +50,9 @@ public class TestSSEConfiguration extends Assert {
   /** Bucket to use for per-bucket options. */
   public static final String BUCKET = "dataset-1";
 
+  /** Valid set of key/value pairs for the encryption context. */
+  private static final String VALID_ENCRYPTION_CONTEXT = "key1=value1, key2=value2, key3=value3";
+
   @Rule
   public Timeout testTimeout = new Timeout(
       S3ATestConstants.S3A_TEST_TIMEOUT
@@ -58,41 +63,41 @@ public class TestSSEConfiguration extends Assert {
 
   @Test
   public void testSSECNoKey() throws Throwable {
-    assertGetAlgorithmFails(SSE_C_NO_KEY_ERROR, SSE_C.getMethod(), null);
+    assertGetAlgorithmFails(SSE_C_NO_KEY_ERROR, SSE_C.getMethod(), null, null);
   }
 
   @Test
   public void testSSECBlankKey() throws Throwable {
-    assertGetAlgorithmFails(SSE_C_NO_KEY_ERROR, SSE_C.getMethod(), "");
+    assertGetAlgorithmFails(SSE_C_NO_KEY_ERROR, SSE_C.getMethod(), "", null);
   }
 
   @Test
   public void testSSECGoodKey() throws Throwable {
-    assertEquals(SSE_C, getAlgorithm(SSE_C, "sseckey"));
+    assertEquals(SSE_C, getAlgorithm(SSE_C, "sseckey", null));
   }
 
   @Test
   public void testKMSGoodKey() throws Throwable {
-    assertEquals(SSE_KMS, getAlgorithm(SSE_KMS, "kmskey"));
+    assertEquals(SSE_KMS, getAlgorithm(SSE_KMS, "kmskey", null));
   }
 
   @Test
   public void testAESKeySet() throws Throwable {
     assertGetAlgorithmFails(SSE_S3_WITH_KEY_ERROR,
-        SSE_S3.getMethod(), "setkey");
+        SSE_S3.getMethod(), "setkey", null);
   }
 
   @Test
   public void testSSEEmptyKey() {
     // test the internal logic of the test setup code
-    Configuration c = buildConf(SSE_C.getMethod(), "");
+    Configuration c = buildConf(SSE_C.getMethod(), "", null);
     assertEquals("", getS3EncryptionKey(BUCKET, c));
   }
 
   @Test
   public void testSSEKeyNull() throws Throwable {
     // test the internal logic of the test setup code
-    final Configuration c = buildConf(SSE_C.getMethod(), null);
+    final Configuration c = buildConf(SSE_C.getMethod(), null, null);
     assertEquals("", getS3EncryptionKey(BUCKET, c));
 
     intercept(IOException.class, SSE_C_NO_KEY_ERROR,
@@ -147,28 +152,30 @@ void setProviderOption(final Configuration conf,
   }
 
   /**
-   * Assert that the exception text from {@link #getAlgorithm(String, String)}
+   * Assert that the exception text from {@link #getAlgorithm(String, String, String)}
    * is as expected.
    * @param expected expected substring in error
    * @param alg algorithm to ask for
    * @param key optional key value
+   * @param context optional encryption context value
    * @throws Exception anything else which gets raised
    */
   public void assertGetAlgorithmFails(String expected,
-      final String alg, final String key) throws Exception {
+      final String alg, final String key, final String context) throws Exception {
     intercept(IOException.class, expected,
-        () -> getAlgorithm(alg, key));
+        () -> getAlgorithm(alg, key, context));
   }
 
   private S3AEncryptionMethods getAlgorithm(S3AEncryptionMethods algorithm,
-      String key)
+      String key,
+      String encryptionContext)
       throws IOException {
-    return getAlgorithm(algorithm.getMethod(), key);
+    return getAlgorithm(algorithm.getMethod(), key, encryptionContext);
   }
 
-  private S3AEncryptionMethods getAlgorithm(String algorithm, String key)
+  private S3AEncryptionMethods getAlgorithm(String algorithm, String key, String encryptionContext)
       throws IOException {
-    return getEncryptionAlgorithm(BUCKET, buildConf(algorithm, key));
+    return getEncryptionAlgorithm(BUCKET, buildConf(algorithm, key, encryptionContext));
   }
 
   /**
@@ -176,10 +183,11 @@ private S3AEncryptionMethods getAlgorithm(String algorithm, String key)
    * and key.
    * @param algorithm  algorithm to use, may be null
    * @param key key, may be null
+   * @param encryptionContext encryption context, may be null
    * @return the new config.
    */
   @SuppressWarnings("deprecation")
-  private Configuration buildConf(String algorithm, String key) {
+  private Configuration buildConf(String algorithm, String key, String encryptionContext) {
     Configuration conf = emptyConf();
     if (algorithm != null) {
       conf.set(Constants.S3_ENCRYPTION_ALGORITHM, algorithm);
@@ -193,6 +201,11 @@ private Configuration buildConf(String algorithm, String key) {
       conf.unset(SERVER_SIDE_ENCRYPTION_KEY);
       conf.unset(Constants.S3_ENCRYPTION_KEY);
     }
+    if (encryptionContext != null) {
+      conf.set(S3_ENCRYPTION_CONTEXT, encryptionContext);
+    } else {
+      conf.unset(S3_ENCRYPTION_CONTEXT);
+    }
     return conf;
   }
 
@@ -308,4 +321,30 @@ public void testNoEncryptionMethod() throws Throwable {
     assertEquals(NONE, getMethod(" "));
   }
 
+  @Test
+  public void testGoodEncryptionContext() throws Throwable {
+    assertEquals(SSE_KMS, getAlgorithm(SSE_KMS, "kmskey", VALID_ENCRYPTION_CONTEXT));
+  }
+
+  @Test
+  public void testSSEEmptyEncryptionContext() throws Throwable {
+    // test the internal logic of the test setup code
+    Configuration c = buildConf(SSE_KMS.getMethod(), "kmskey", "");
+    assertEquals("", S3AEncryption.getS3EncryptionContext(BUCKET, c));
+  }
+
+  @Test
+  public void testSSEEncryptionContextNull() throws Throwable {
+    // test the internal logic of the test setup code
+    final Configuration c = buildConf(SSE_KMS.getMethod(), "kmskey", null);
+    assertEquals("", S3AEncryption.getS3EncryptionContext(BUCKET, c));
+  }
+
+  @Test
+  public void testSSEInvalidEncryptionContext() throws Throwable {
+    intercept(IllegalArgumentException.class,
+        StringUtils.STRING_COLLECTION_SPLIT_EQUALS_INVALID_ARG,
+        () -> getAlgorithm(SSE_KMS.getMethod(), "kmskey", "invalid context"));
+  }
+
 }

hadoop-tools/hadoop-aws/src/test/java/org/apache/hadoop/fs/s3a/auth/TestMarshalledCredentials.java

@@ -80,7 +80,8 @@ public void testRoundTripNoSessionData() throws Throwable {
   public void testRoundTripEncryptionData() throws Throwable {
     EncryptionSecrets secrets = new EncryptionSecrets(
         S3AEncryptionMethods.SSE_KMS,
-        "key");
+        "key",
+        "encryptionContext");
     EncryptionSecrets result = S3ATestUtils.roundTrip(secrets,
         new Configuration());
     assertEquals("round trip", secrets, result);

hadoop-tools/hadoop-aws/src/test/java/org/apache/hadoop/fs/s3a/auth/delegation/ITestSessionDelegationTokens.java

@@ -116,7 +116,7 @@ public void testCanonicalization() throws Throwable {
   public void testSaveLoadTokens() throws Throwable {
     File tokenFile = File.createTempFile("token", "bin");
     EncryptionSecrets encryptionSecrets = new EncryptionSecrets(
-        S3AEncryptionMethods.SSE_KMS, KMS_KEY);
+        S3AEncryptionMethods.SSE_KMS, KMS_KEY, "");
     Token<AbstractS3ATokenIdentifier> dt
         = delegationTokens.createDelegationToken(encryptionSecrets, null);
     final SessionTokenIdentifier origIdentifier
@@ -171,7 +171,7 @@ public void testCreateAndUseDT() throws Throwable {
     assertNull("Current User has delegation token",
         delegationTokens.selectTokenFromFSOwner());
     EncryptionSecrets secrets = new EncryptionSecrets(
-        S3AEncryptionMethods.SSE_KMS, KMS_KEY);
+        S3AEncryptionMethods.SSE_KMS, KMS_KEY, "");
     Token<AbstractS3ATokenIdentifier> originalDT
         = delegationTokens.createDelegationToken(secrets, null);
     assertEquals("Token kind mismatch", getTokenKind(), originalDT.getKind());
@@ -229,7 +229,7 @@ public void testCreateWithRenewer() throws Throwable {
     assertNull("Current User has delegation token",
         delegationTokens.selectTokenFromFSOwner());
     EncryptionSecrets secrets = new EncryptionSecrets(
-        S3AEncryptionMethods.SSE_KMS, KMS_KEY);
+        S3AEncryptionMethods.SSE_KMS, KMS_KEY, "");
     Token<AbstractS3ATokenIdentifier> dt
         = delegationTokens.createDelegationToken(secrets, renewer);
     assertEquals("Token kind mismatch", getTokenKind(), dt.getKind());

hadoop-tools/hadoop-aws/src/test/java/org/apache/hadoop/fs/s3a/auth/delegation/TestS3ADelegationTokenSupport.java

@@ -19,10 +19,12 @@
 package org.apache.hadoop.fs.s3a.auth.delegation;
 
 import java.net.URI;
+import java.nio.charset.StandardCharsets;
 
 import org.junit.BeforeClass;
 import org.junit.Test;
 
+import org.apache.commons.codec.binary.Base64;
 import org.apache.hadoop.fs.s3a.S3AEncryptionMethods;
 import org.apache.hadoop.fs.s3a.S3ATestUtils;
 import org.apache.hadoop.fs.s3a.auth.MarshalledCredentialBinding;
@@ -70,13 +72,17 @@ public void testSessionTokenIssueDate() throws Throwable {
   public void testSessionTokenDecode() throws Throwable {
     Text alice = new Text("alice");
     Text renewer = new Text("yarn");
+    String encryptionKey = "encryptionKey";
+    String encryptionContextJson = "{\"key\":\"value\", \"key2\": \"value3\"}";
+    String encryptionContextEncoded = Base64.encodeBase64String(encryptionContextJson.getBytes(
+        StandardCharsets.UTF_8));
     AbstractS3ATokenIdentifier identifier
         = new SessionTokenIdentifier(SESSION_TOKEN_KIND,
         alice,
         renewer,
         new URI("s3a://anything/"),
         new MarshalledCredentials("a", "b", ""),
-        new EncryptionSecrets(S3AEncryptionMethods.SSE_S3, ""),
+        new EncryptionSecrets(S3AEncryptionMethods.SSE_S3, encryptionKey, encryptionContextEncoded),
         "origin");
     Token<AbstractS3ATokenIdentifier> t1 =
         new Token<>(identifier,
@@ -100,6 +106,10 @@ public void testSessionTokenDecode() throws Throwable {
     assertEquals("origin", decoded.getOrigin());
     assertEquals("issue date", identifier.getIssueDate(),
         decoded.getIssueDate());
+    EncryptionSecrets encryptionSecrets = decoded.getEncryptionSecrets();
+    assertEquals(S3AEncryptionMethods.SSE_S3, encryptionSecrets.getEncryptionMethod());
+    assertEquals(encryptionKey, encryptionSecrets.getEncryptionKey());
+    assertEquals(encryptionContextEncoded, encryptionSecrets.getEncryptionContext());
   }
 
   @Test
@@ -112,13 +122,19 @@ public void testFullTokenKind() throws Throwable {
   @Test
   public void testSessionTokenIdentifierRoundTrip() throws Throwable {
     Text renewer = new Text("yarn");
+    String encryptionKey = "encryptionKey";
+    String encryptionContextJson = "{\"key\":\"value\", \"key2\": \"value3\"}";
+    String encryptionContextEncoded = Base64.encodeBase64String(encryptionContextJson.getBytes(
+        StandardCharsets.UTF_8));
     SessionTokenIdentifier id = new SessionTokenIdentifier(
         SESSION_TOKEN_KIND,
         new Text(),
         renewer,
         externalUri,
         new MarshalledCredentials("a", "b", "c"),
-        new EncryptionSecrets(), "");
+        new EncryptionSecrets(S3AEncryptionMethods.DSSE_KMS, encryptionKey,
+            encryptionContextEncoded),
+        "");
 
     SessionTokenIdentifier result = S3ATestUtils.roundTrip(id, null);
     String ids = id.toString();
@@ -127,6 +143,10 @@ public void testSessionTokenIdentifierRoundTrip() throws Throwable {
         id.getMarshalledCredentials(),
         result.getMarshalledCredentials());
     assertEquals("renewer in " + ids, renewer, id.getRenewer());
+    EncryptionSecrets encryptionSecrets = result.getEncryptionSecrets();
+    assertEquals(S3AEncryptionMethods.DSSE_KMS, encryptionSecrets.getEncryptionMethod());
+    assertEquals(encryptionKey, encryptionSecrets.getEncryptionKey());
+    assertEquals(encryptionContextEncoded, encryptionSecrets.getEncryptionContext());
   }
 
   @Test

hadoop-tools/hadoop-aws/src/test/java/org/apache/hadoop/fs/s3a/impl/TestRequestFactory.java

@@ -70,7 +70,7 @@ public void testRequestFactoryWithEncryption() throws Throwable {
         .withBucket("bucket")
         .withEncryptionSecrets(
             new EncryptionSecrets(S3AEncryptionMethods.SSE_KMS,
-                "kms:key"))
+                "kms:key", ""))
         .build();
     createFactoryObjects(factory);
   }

hadoop-tools/hadoop-aws/src/test/java/org/apache/hadoop/fs/s3a/impl/TestS3AEncryption.java

@@ -0,0 +1,77 @@
+/**
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.hadoop.fs.s3a.impl;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.Map;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.junit.Assert;
+import org.junit.Test;
+
+import org.apache.commons.codec.binary.Base64;
+import org.apache.hadoop.conf.Configuration;
+
+import static org.apache.hadoop.fs.s3a.Constants.S3_ENCRYPTION_CONTEXT;
+
+public class TestS3AEncryption {
+
+  private static final String GLOBAL_CONTEXT = "  project=hadoop, jira=HADOOP-19197  ";
+  private static final String BUCKET_CONTEXT = "component=fs/s3";
+
+  @Test
+  public void testGetS3EncryptionContextPerBucket() throws IOException {
+    Configuration configuration = new Configuration(false);
+    configuration.set("fs.s3a.bucket.bucket1.encryption.context", BUCKET_CONTEXT);
+    configuration.set(S3_ENCRYPTION_CONTEXT, GLOBAL_CONTEXT);
+    final String result = S3AEncryption.getS3EncryptionContext("bucket1", configuration);
+    Assert.assertEquals(BUCKET_CONTEXT, result);
+  }
+
+  @Test
+  public void testGetS3EncryptionContextFromGlobal() throws IOException {
+    Configuration configuration = new Configuration(false);
+    configuration.set("fs.s3a.bucket.bucket1.encryption.context", BUCKET_CONTEXT);
+    configuration.set(S3_ENCRYPTION_CONTEXT, GLOBAL_CONTEXT);
+    final String result = S3AEncryption.getS3EncryptionContext("bucket2", configuration);
+    Assert.assertEquals(GLOBAL_CONTEXT.trim(), result);
+  }
+
+  @Test
+  public void testGetS3EncryptionContextNoSet() throws IOException {
+    Configuration configuration = new Configuration(false);
+    final String result = S3AEncryption.getS3EncryptionContext("bucket1", configuration);
+    Assert.assertEquals("", result);
+  }
+
+  @Test
+  public void testGetS3EncryptionContextBase64Encoded() throws IOException {
+    Configuration configuration = new Configuration(false);
+    configuration.set(S3_ENCRYPTION_CONTEXT, GLOBAL_CONTEXT);
+    final String result = S3AEncryption.getS3EncryptionContextBase64Encoded("bucket",
+        configuration, true);
+    final String decoded = new String(Base64.decodeBase64(result), StandardCharsets.UTF_8);
+    final TypeReference<Map<String, String>> typeRef = new TypeReference<Map<String, String>>() {};
+    final Map<String, String> resultMap = new ObjectMapper().readValue(decoded, typeRef);
+    Assert.assertEquals("hadoop", resultMap.get("project"));
+    Assert.assertEquals("HADOOP-19197", resultMap.get("jira"));
+  }
+}