CVE-2018-12537 (published 2018-08-14T19:29Z)

In Eclipse Vert.x version 3.0 to 3.5.1, the HttpServer response headers and HttpClient request headers do not filter carriage return and line feed characters from the header value. This allow unfiltered values to inject a new header in the client request or server response.

Severity: MEDIUM
CVSS v2 base score: 5.0 (AV:N/AC:L/Au:N/C:N/I:P/A:N)
CVSS v3 base score: 5.3, MEDIUM (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N)

Weakness information:
cwe_id: CWE-20
cwe_name: Improper Input Validation
description: The product receives input or data, but it does
        not validate or incorrectly validates that the input has the
        properties that are required to process the data safely and
        correctly.
extended_description: 
	   Input validation is a frequently-used technique
	   for checking potentially dangerous inputs in order to
	   ensure that the inputs are safe for processing within the
	   code, or when communicating with other components.  When
	   software does not validate input properly, an attacker is
	   able to craft the input in a form that is not expected by
	   the rest of the application. This will lead to parts of the
	   system receiving unintended input, which may result in
	   altered control flow, arbitrary control of a resource, or
	   arbitrary code execution.
	   Input validation is not the only technique for
	   processing input, however.  Other techniques attempt to
	   transform potentially-dangerous input into something safe, such
	   as filtering (CWE-790) - which attempts to remove dangerous
	   inputs - or encoding/escaping (CWE-116), which attempts to
	   ensure that the input is not misinterpreted when it is included
	   in output to another component. Other techniques exist as well
	   (see CWE-138 for more examples.)
	   Input validation can be applied to:
	   
	     raw data - strings, numbers, parameters, file contents, etc.
	     metadata - information about the raw data, such as headers or size
	   
	   Data can be simple or structured.  Structured data
	   can be composed of many nested layers, composed of
	   combinations of metadata and raw data, with other simple or
	   structured data.
	   Many properties of raw data or metadata may need
	   to be validated upon entry into the code, such
	   as:
	   
	     specified quantities such as size, length, frequency, price, rate, number of operations, time, etc.
	     implied or derived quantities, such as the actual size of a file instead of a specified size
	     indexes, offsets, or positions into more complex data structures
	     symbolic keys or other elements into hash tables, associative arrays, etc.
	     well-formedness, i.e. syntactic correctness - compliance with expected syntax 
	     lexical token correctness - compliance with rules for what is treated as a token
	     specified or derived type - the actual type of the input (or what the input appears to be)
	     consistency - between individual data elements, between raw data and metadata, between references, etc.
	     conformance to domain-specific rules, e.g. business logic 
	     equivalence - ensuring that equivalent inputs are treated the same
	     authenticity, ownership, or other attestations about the input, e.g. a cryptographic signature to prove the source of the data
	   
	   Implied or derived properties of data must often
	   be calculated or inferred by the code itself.  Errors in
	   deriving properties may be considered a contributing factor
	   to improper input validation.
	   
	   Note that "input validation" has very different
	   meanings to different people, or within different
	   classification schemes.  Caution must be used when
	   referencing this CWE entry or mapping to it.  For example,
	   some weaknesses might involve inadvertently giving control
	   to an attacker over an input when they should not be able
	   to provide an input at all, but sometimes this is referred
	   to as input validation.
	   Finally, it is important to emphasize that the
	   distinctions between input validation and output escaping
	   are often blurred, and developers must be careful to
	   understand the difference, including how input validation
	   is not always sufficient to prevent vulnerabilities,
	   especially when less stringent data types must be
	   supported, such as free-form text. Consider a SQL injection
	   scenario in which a person's last name is inserted into a
	   query. The name "O'Reilly" would likely pass the validation
	   step since it is a common last name in the English
	   language. However, this valid name cannot be directly
	   inserted into the database because it contains the "'"
	   apostrophe character, which would need to be escaped or
	   otherwise transformed. In this case, removing the
	   apostrophe might reduce the risk of SQL injection, but it
	   would produce incorrect behavior because the wrong name
	   would be recorded.
       
         

Fix information:
repo_url: https://github.com/eclipse/vert.x
commit_details: repo_url: https://github.com/eclipse/vert.x
author: Julien Viet
author_date: 2018-05-23 12:31:59+02:00
msg: Http header CR / LF validation - fixes #2470
repository: repo_url: https://github.com/eclipse/vert.x
repo_name: eclipse-vertx/vert.x
description: Vert.x is a tool-kit for building reactive applications on the JVM
repo_language: Java
owner: eclipse
file_changes: filename: HttpHeaders.java
change_type: ModificationType.MODIFY
diff: @@ -11,6 +11,9 @@
 
 package io.vertx.core.http;
 
+import io.netty.util.AsciiString;
+import io.vertx.core.http.impl.HttpUtils;
+
 /**
  * Contains often used Header names.
  * <p>
@@ -324,7 +327,8 @@ public final class HttpHeaders {
    * for multiple responses or requests.
    */
   public static CharSequence createOptimized(String value) {
-    return io.netty.handler.codec.http.HttpHeaders.newEntity(value);
+    HttpUtils.validateHeader(value);
+    return new AsciiString(value);
   }
 
   private HttpHeaders() {

programming_language: Java
filename: Http2HeadersAdaptor.java
change_type: ModificationType.MODIFY
diff: @@ -139,12 +139,14 @@ public class Http2HeadersAdaptor implements MultiMap {
 
   @Override
   public MultiMap add(String name, String value) {
+    HttpUtils.validateHeader(name, value);
     headers.add(toLowerCase(name), value);
     return this;
   }
 
   @Override
   public MultiMap add(String name, Iterable<String> values) {
+    HttpUtils.validateHeader(name, values);
     headers.add(toLowerCase(name), values);
     return this;
   }
@@ -167,12 +169,14 @@ public class Http2HeadersAdaptor implements MultiMap {
 
   @Override
   public MultiMap set(String name, String value) {
+    HttpUtils.validateHeader(name, value);
     headers.set(toLowerCase(name), value);
     return this;
   }
 
   @Override
   public MultiMap set(String name, Iterable<String> values) {
+    HttpUtils.validateHeader(name, values);
     headers.set(toLowerCase(name), values);
     return this;
   }
@@ -240,24 +244,28 @@ public class Http2HeadersAdaptor implements MultiMap {
 
   @Override
   public MultiMap add(CharSequence name, CharSequence value) {
+    HttpUtils.validateHeader(name, value);
     headers.add(toLowerCase(name), value);
     return this;
   }
 
   @Override
   public MultiMap add(CharSequence name, Iterable<CharSequence> values) {
+    HttpUtils.validateHeader(name, values);
     headers.add(toLowerCase(name), values);
     return this;
   }
 
   @Override
   public MultiMap set(CharSequence name, CharSequence value) {
+    HttpUtils.validateHeader(name, value);
     headers.set(toLowerCase(name), value);
     return this;
   }
 
   @Override
   public MultiMap set(CharSequence name, Iterable<CharSequence> values) {
+    HttpUtils.validateHeader(name, values);
     headers.set(toLowerCase(name), values);
     return this;
   }

programming_language: Java
filename: Http2ServerResponseImpl.java
change_type: ModificationType.MODIFY
diff: @@ -13,7 +13,6 @@ package io.vertx.core.http.impl;
 
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
-import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.http.HttpHeaderNames;
@@ -26,7 +25,6 @@ import io.vertx.core.Context;
 import io.vertx.core.Future;
 import io.vertx.core.Handler;
 import io.vertx.core.MultiMap;
-import io.vertx.core.VertxException;
 import io.vertx.core.buffer.Buffer;
 import io.vertx.core.http.HttpMethod;
 import io.vertx.core.http.HttpServerResponse;

programming_language: Java
filename: HttpClientRequestImpl.java
change_type: ModificationType.MODIFY
diff: @@ -17,13 +17,13 @@ import io.netty.buffer.Unpooled;
 import io.vertx.codegen.annotations.Nullable;
 import io.vertx.core.*;
 import io.vertx.core.buffer.Buffer;
-import io.vertx.core.http.CaseInsensitiveHeaders;
 import io.vertx.core.http.HttpClientRequest;
 import io.vertx.core.http.HttpClientResponse;
 import io.vertx.core.http.HttpConnection;
 import io.vertx.core.http.HttpFrame;
 import io.vertx.core.http.HttpMethod;
 import io.vertx.core.http.HttpVersion;
+import io.vertx.core.http.impl.headers.VertxHttpHeaders;
 import io.vertx.core.impl.ContextInternal;
 import io.vertx.core.impl.VertxInternal;
 import io.vertx.core.logging.Logger;
@@ -68,7 +68,7 @@ public class HttpClientRequestImpl extends HttpClientRequestBase implements Http
   private int pendingMaxSize = -1;
   private int followRedirects;
   private long written;
-  private CaseInsensitiveHeaders headers;
+  private VertxHttpHeaders headers;
 
   private HttpClientStream stream;
   private boolean connecting;
@@ -183,7 +183,7 @@ public class HttpClientRequestImpl extends HttpClientRequestBase implements Http
   @Override
   public synchronized MultiMap headers() {
     if (headers == null) {
-      headers = new CaseInsensitiveHeaders();
+      headers = new VertxHttpHeaders();
     }
     return headers;
   }

programming_language: Java
filename: HttpUtils.java
change_type: ModificationType.MODIFY
diff: @@ -521,4 +521,23 @@ public final class HttpUtils {
     }
     return -1;
   }
+
+  public static void validateHeader(CharSequence name, CharSequence value) {
+    validateHeader(name);
+    validateHeader(value);
+  }
+
+  public static void validateHeader(CharSequence name, Iterable<? extends CharSequence> values) {
+    validateHeader(name);
+    values.forEach(HttpUtils::validateHeader);
+  }
+
+  public static void validateHeader(CharSequence value) {
+    for (int i = 0;i < value.length();i++) {
+      char c = value.charAt(i);
+      if (c == '\r' || c == '\n') {
+        throw new IllegalArgumentException("Illegal header character: " + ((int)c));
+      }
+    }
+  }
 }

programming_language: Java
filename: VertxHttpHeaders.java
change_type: ModificationType.MODIFY
diff: @@ -15,6 +15,7 @@ import io.netty.handler.codec.http.HttpHeaders;
 import io.netty.util.AsciiString;
 import io.netty.util.HashingStrategy;
 import io.vertx.core.MultiMap;
+import io.vertx.core.http.impl.HttpUtils;
 
 import java.util.AbstractMap;
 import java.util.ArrayList;
@@ -54,7 +55,7 @@ public final class VertxHttpHeaders extends HttpHeaders implements MultiMap {
   }
 
   private final VertxHttpHeaders.MapEntry[] entries = new VertxHttpHeaders.MapEntry[16];
-  private final VertxHttpHeaders.MapEntry head = new VertxHttpHeaders.MapEntry(-1, null, null);
+  private final VertxHttpHeaders.MapEntry head = new VertxHttpHeaders.MapEntry();
 
   public VertxHttpHeaders() {
     head.before = head.after = head;
@@ -397,6 +398,12 @@ public final class VertxHttpHeaders extends HttpHeaders implements MultiMap {
     VertxHttpHeaders.MapEntry next;
     VertxHttpHeaders.MapEntry before, after;
 
+    MapEntry() {
+      this.hash = -1;
+      this.key = null;
+      this.value = null;
+    }
+
     MapEntry(int hash, CharSequence key, CharSequence value) {
       this.hash = hash;
       this.key = key;
@@ -476,6 +483,12 @@ public final class VertxHttpHeaders extends HttpHeaders implements MultiMap {
   }
 
   private void add0(int h, int i, final CharSequence name, final CharSequence value) {
+    if (!(name instanceof AsciiString)) {
+      HttpUtils.validateHeader(name);
+    }
+    if (!(value instanceof AsciiString)) {
+      HttpUtils.validateHeader(value);
+    }
     // Update the hash table.
     VertxHttpHeaders.MapEntry e = entries[i];
     VertxHttpHeaders.MapEntry newEntry;

programming_language: Java
filename: HttpTest.java
change_type: ModificationType.MODIFY
diff: @@ -49,12 +49,7 @@ import java.io.OutputStreamWriter;
 import java.io.UnsupportedEncodingException;
 import java.net.InetAddress;
 import java.net.URLEncoder;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.UUID;
+import java.util.*;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutorService;
@@ -64,6 +59,7 @@ import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.BiConsumer;
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.stream.IntStream;
@@ -86,7 +82,7 @@ public abstract class HttpTest extends HttpTestBase {
     super.setUp();
     testDir = testFolder.newFolder();
   }
-    
+
   protected HttpServerOptions createBaseServerOptions() {
     return new HttpServerOptions().setPort(DEFAULT_HTTP_PORT).setHost(DEFAULT_HTTP_HOST);
   }
@@ -176,7 +172,7 @@ public abstract class HttpTest extends HttpTestBase {
     }
   }
 
-    
+
   @Test
   public void testLowerCaseHeaders() {
     server.requestHandler(req -> {
@@ -4272,6 +4268,78 @@ public abstract class HttpTest extends HttpTestBase {
     return headers;
   }
 
+  @Test
+  public void testHttpClientRequestHeadersDontContainCROrLF() throws Exception {
+    server.requestHandler(req -> {
+      req.headers().forEach(header -> {
+        String name = header.getKey();
+        switch (name.toLowerCase()) {
+          case "host":
+          case ":method":
+          case ":path":
+          case ":scheme":
+          case ":authority":
+            break;
+          default:
+            fail("Unexpected header " + name);
+        }
+      });
+      testComplete();
+    });
+    startServer();
+    HttpClientRequest req = client.get(DEFAULT_HTTP_PORT, DEFAULT_HTTP_HOST, DEFAULT_TEST_URI, resp -> {});
+    List<BiConsumer<String, String>> list = Arrays.asList(
+      req::putHeader,
+      req.headers()::set,
+      req.headers()::add
+    );
+    list.forEach(cs -> {
+      try {
+        req.putHeader("header-name: header-value\r\nanother-header", "another-value");
+        fail();
+      } catch (IllegalArgumentException e) {
+      }
+    });
+    assertEquals(0, req.headers().size());
+    req.end();
+    await();
+  }
+
+  @Test
+  public void testHttpServerResponseHeadersDontContainCROrLF() throws Exception {
+    server.requestHandler(req -> {
+      List<BiConsumer<String, String>> list = Arrays.asList(
+        req.response()::putHeader,
+        req.response().headers()::set,
+        req.response().headers()::add
+      );
+      list.forEach(cs -> {
+        try {
+          cs.accept("header-name: header-value\r\nanother-header", "another-value");
+          fail();
+        } catch (IllegalArgumentException e) {
+        }
+      });
+      assertEquals(Collections.emptySet(), req.response().headers().names());
+      req.response().end();
+    });
+    startServer();
+    client.getNow(DEFAULT_HTTP_PORT, DEFAULT_HTTP_HOST, DEFAULT_TEST_URI, resp -> {
+      resp.headers().forEach(header -> {
+        String name = header.getKey();
+        switch (name.toLowerCase()) {
+          case ":status":
+          case "content-length":
+            break;
+          default:
+            fail("Unexpected header " + name);
+        }
+      });
+      testComplete();
+    });
+    await();
+  }
+
   /*
   @Test
   public void testReset() throws Exception {

programming_language: Java
filename: VertxHttpHeadersTest.java
change_type: ModificationType.MODIFY
diff: @@ -13,6 +13,7 @@ package io.vertx.test.core;
 
 import io.vertx.core.MultiMap;
 import io.vertx.core.http.impl.headers.VertxHttpHeaders;
+import org.junit.Test;
 
 /**
  * @author <a href="mailto:julien@julienviet.com">Julien Viet</a>
@@ -23,4 +24,9 @@ public class VertxHttpHeadersTest extends CaseInsensitiveHeadersTest {
   protected MultiMap newMultiMap() {
     return new VertxHttpHeaders();
   }
+
+  @Override
+  public void testHashMININT() {
+    // Does not apply
+  }
 }

programming_language: Java