Fix InvalidMimeTypeException for compatible media types

The `AbstractMessageConverterMethodProcessor` is in charge of handling
controller method return values and to write those as HTTP response
messages. The content negotiation process is an important part.

The `MimeTypeUtils#sortBySpecificity` is in charge of sorting inbound
"Accept" media types by their specificity and reject them if the list
is too large, in order to protect the application from ddos attacks.

Prior to this commit, the content negotiation process would first get
the sorted "Accept" media types, the producible media types as
advertized by message converters - and collect the intersection of both
in a new list (also sorted by specificity). If the "Accept" list is
large enough (but under the limit), the list of compatible media types
could exceed that limit because duplicates could be introduced in that
list: several converters can produce the same content type.

This commit ensures that compatible media types are collected in a set
to avoid duplicates. Without that, exceeding the limit at this point
will throw an `InvalidMimeTypeException` that's not handled by the
processor and result in a server error.

Fixes gh-36300
This commit is contained in:
Brian Clozel
2026-02-20 18:21:45 +01:00
parent 50ef3b0a29
commit a3f7179ab3
2 changed files with 27 additions and 6 deletions
@@ -24,6 +24,8 @@ import java.lang.reflect.Type;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.annotation.JsonTypeName;
@@ -783,6 +785,24 @@ class RequestResponseBodyMethodProcessorTests {
assertThat(value).isEqualTo("foo");
}
@Test // gh-36300
void shouldNotDuplicateInCompatibleMediaTypes() throws Exception {
Method method = TestRestController.class.getMethod("handle");
MethodParameter returnType = new MethodParameter(method, -1);
List<HttpMessageConverter<?>> converters = List.of(new StringHttpMessageConverter(), new MappingJackson2HttpMessageConverter());
RequestResponseBodyMethodProcessor processor = new RequestResponseBodyMethodProcessor(converters);
String accept = Stream.iterate(1, i -> i + 1)
.limit(48).map(i -> "application/" + i)
.collect(Collectors.joining(","));
accept = accept + ", application/json";
this.servletRequest.addHeader("Accept", accept);
processor.writeWithMessageConverters("spring framework", returnType, this.request);
}
private void assertContentDisposition(RequestResponseBodyMethodProcessor processor,
boolean expectContentDisposition, String requestURI, String comment) throws Exception {