JWE arbitrary content compression (#937)

Closes #938.

* Fix compression being omitted for JWEs with arbitrary content

The JWE content was compressed only when claims was used as payload, but
when using arbitrary content, the compression was omitted, while keeping
the "zip" header field, leading to decompression failing.

* Refactor duplicate payload -> input stream logic from sign()/encrypt()

* Preserve the content name

* Fix name for JWE payload

impl/src/main/java/io/jsonwebtoken/impl/DefaultJwtBuilder.java

@@ -595,14 +595,8 @@ public class DefaultJwtBuilder implements JwtBuilder {
 
             // Next, b64 extension requires the raw (non-encoded) payload to be included directly in the signing input,
             // so we ensure we have an input stream for that:
-            if (payload.isClaims() || payload.isCompressed()) {
+            payloadStream = toInputStream("JWS Unencoded Payload", payload);
-                ByteArrayOutputStream claimsOut = new ByteArrayOutputStream(8192);
+
-                writeAndClose("JWS Unencoded Payload", payload, claimsOut);
-                payloadStream = Streams.of(claimsOut.toByteArray());
-            } else {
-                // No claims and not compressed, so just get the direct InputStream:
-                payloadStream = Assert.stateNotNull(payload.toInputStream(), "Payload InputStream cannot be null.");
-            }
             if (!payload.isClaims()) {
                 payloadStream = new CountingInputStream(payloadStream); // we'll need to assert if it's empty later
             }
@@ -693,14 +687,7 @@ public class DefaultJwtBuilder implements JwtBuilder {
         Assert.stateNotNull(keyAlgFunction, "KeyAlgorithm function cannot be null.");
         assertPayloadEncoding("JWE");
 
-        InputStream plaintext;
+        InputStream plaintext = toInputStream("JWE Payload", content);
-        if (content.isClaims()) {
-            ByteArrayOutputStream out = new ByteArrayOutputStream(4096);
-            writeAndClose("JWE Claims", content, out);
-            plaintext = Streams.of(out.toByteArray());
-        } else {
-            plaintext = content.toInputStream();
-        }
 
         //only expose (mutable) JweHeader functionality to KeyAlgorithm instances, not the full headerBuilder
         // (which exposes this JwtBuilder and shouldn't be referenced by KeyAlgorithms):
@@ -820,4 +807,15 @@ public class DefaultJwtBuilder implements JwtBuilder {
         Streams.writeAndClose(out, data, "Unable to write bytes");
     }
 
+    private InputStream toInputStream(final String name, Payload payload) {
+        if (payload.isClaims() || payload.isCompressed()) {
+            ByteArrayOutputStream claimsOut = new ByteArrayOutputStream(8192);
+            writeAndClose(name, payload, claimsOut);
+            return Streams.of(claimsOut.toByteArray());
+        } else {
+            // No claims and not compressed, so just get the direct InputStream:
+            return Assert.stateNotNull(payload.toInputStream(), "Payload InputStream cannot be null.");
+        }
+    }
+
 }

impl/src/test/groovy/io/jsonwebtoken/JwtsTest.groovy

@@ -22,6 +22,7 @@ import io.jsonwebtoken.impl.io.Streams
 import io.jsonwebtoken.impl.lang.Bytes
 import io.jsonwebtoken.impl.lang.Services
 import io.jsonwebtoken.impl.security.*
+import io.jsonwebtoken.io.CompressionAlgorithm
 import io.jsonwebtoken.io.Decoders
 import io.jsonwebtoken.io.Deserializer
 import io.jsonwebtoken.io.Encoders
@@ -1398,6 +1399,97 @@ class JwtsTest {
         }
     }
 
+    @Test
+    void testJweCompressionWithArbitraryContentString() {
+        def codecs = [Jwts.ZIP.DEF, Jwts.ZIP.GZIP]
+
+        for (CompressionAlgorithm zip : codecs) {
+
+            for (AeadAlgorithm enc : Jwts.ENC.get().values()) {
+
+                SecretKey key = enc.key().build()
+
+                String payload = 'hello, world!'
+
+                // encrypt and compress:
+                String jwe = Jwts.builder()
+                    .content(payload)
+                    .compressWith(zip)
+                    .encryptWith(key, enc)
+                    .compact()
+
+                //decompress and decrypt:
+                def jwt = Jwts.parser()
+                    .decryptWith(key)
+                    .build()
+                    .parseEncryptedContent(jwe)
+                assertEquals payload, new String(jwt.getPayload(), StandardCharsets.UTF_8)
+            }
+        }
+    }
+
+    @Test
+    void testJweCompressionWithArbitraryContentByteArray() {
+        def codecs = [Jwts.ZIP.DEF, Jwts.ZIP.GZIP]
+
+        for (CompressionAlgorithm zip : codecs) {
+
+            for (AeadAlgorithm enc : Jwts.ENC.get().values()) {
+
+                SecretKey key = enc.key().build()
+
+                byte[] payload = new byte[14];
+                Randoms.secureRandom().nextBytes(payload)
+
+                // encrypt and compress:
+                String jwe = Jwts.builder()
+                        .content(payload)
+                        .compressWith(zip)
+                        .encryptWith(key, enc)
+                        .compact()
+
+                //decompress and decrypt:
+                def jwt = Jwts.parser()
+                        .decryptWith(key)
+                        .build()
+                        .parseEncryptedContent(jwe)
+                assertArrayEquals payload, jwt.getPayload()
+            }
+        }
+    }
+
+    @Test
+    void testJweCompressionWithArbitraryContentInputStream() {
+        def codecs = [Jwts.ZIP.DEF, Jwts.ZIP.GZIP]
+
+        for (CompressionAlgorithm zip : codecs) {
+
+            for (AeadAlgorithm enc : Jwts.ENC.get().values()) {
+
+                SecretKey key = enc.key().build()
+
+                byte[] payloadBytes = new byte[14];
+                Randoms.secureRandom().nextBytes(payloadBytes)
+
+                ByteArrayInputStream payload = new ByteArrayInputStream(payloadBytes)
+
+                // encrypt and compress:
+                String jwe = Jwts.builder()
+                        .content(payload)
+                        .compressWith(zip)
+                        .encryptWith(key, enc)
+                        .compact()
+
+                //decompress and decrypt:
+                def jwt = Jwts.parser()
+                        .decryptWith(key)
+                        .build()
+                        .parseEncryptedContent(jwe)
+                assertArrayEquals payloadBytes, jwt.getPayload()
+            }
+        }
+    }
+
     @Test
     void testPasswordJwes() {