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fix: getRemoteHost and getRemotePort for ALB #827

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Merged
merged 4 commits into from
May 10, 2024
Merged

fix: getRemoteHost and getRemotePort for ALB #827

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b0058d1
fix remoteHost for ALB
mbfreder Apr 8, 2024
04a0e63
fix ArrayIndexOutOfBoundsException on getRemotePort()
mbfreder Apr 29, 2024
e7afb3f
fix port header var naming
mbfreder Apr 29, 2024
46d9637
update getRomteAddr()
mbfreder Apr 30, 2024
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22 changes: 18 additions & 4 deletions ...main/java/com/amazonaws/serverless/proxy/internal/servlet/AwsProxyHttpServletRequest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -21,13 +21,15 @@
import com.amazonaws.serverless.proxy.model.RequestSource;
import com.amazonaws.services.lambda.runtime.Context;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import jakarta.servlet.*;
import jakarta.servlet.http.*;
import jakarta.servlet.http.Cookie;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpUpgradeHandler;
import jakarta.ws.rs.core.HttpHeaders;
import jakarta.ws.rs.core.SecurityContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.BufferedReader;
import java.io.IOException;
Expand Down Expand Up @@ -441,6 +443,13 @@ public String getRemoteAddr() {

@Override
public String getRemoteHost() {
if (Objects.nonNull(request.getRequestContext().getElb())) {
String hostHeader = request.getHeaders().get(HttpHeaders.HOST);

// the host header has the form host:port, so we split the string to get the host part
return Arrays.asList(hostHeader.split(":")).get(0);
}

return request.getMultiValueHeaders().getFirst(HttpHeaders.HOST);
}

Expand Down Expand Up @@ -471,6 +480,11 @@ public RequestDispatcher getRequestDispatcher(String s) {

@Override
public int getRemotePort() {
if (Objects.nonNull(request.getRequestContext().getElb())) {
String hostHeader = request.getHeaders().get(PORT_HEADER_NAME);
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Variable naming is misleading as it is no longer the host header.

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Updated. Thanks.

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@mbfreder mbfreder Apr 29, 2024 •
edited
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I think you're right. We need to update getRemoteAddr() to take into account the x-forwarded-for header. For getServerPort(), I'm a bit confused. Looking at the javadoc for both getServerPort() and getRemotePort(), I'm wondering if Returns the Internet Protocol (IP) source port of the client or last proxy that sent the request. and Returns the port number to which the request was sent don't mean the same thing. Is ALB considered as a client in this case?

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To make it even more interesting there is also getLocalPort().

ALB is the last proxy so that should be fine.

For comparison Tomcat sets serverPort based on scheme https://github.com/apache/tomcat/blob/main/java/org/apache/catalina/connector/CoyoteAdapter.java#L579.

if (Objects.nonNull(hostHeader))
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please use brackets for the if statement

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Updated. Thanks

return Integer.parseInt(hostHeader);
}
return 0;
}

Expand Down
12 changes: 12 additions & 0 deletions .../java/com/amazonaws/serverless/proxy/internal/servlet/AwsProxyHttpServletRequestTest.java
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Expand Up @@ -651,6 +651,18 @@ void serverName_albHostHeader_returnsHostHeader() {
assertEquals("testapi.us-east-1.elb.amazonaws.com", serverName);
}

@Test
void getRemoteHost_albHostHeader_returnsHostHeader() {
initAwsProxyHttpServletRequestTest("ALB");
AwsProxyRequest proxyReq = new AwsProxyRequestBuilder("/test", "GET")
.alb().build();
proxyReq.getHeaders().put(HttpHeaders.HOST, "testapi.us-east-1.elb.amazonaws.com");
HttpServletRequest servletRequest = new AwsProxyHttpServletRequest(proxyReq, null, null);

String host = servletRequest.getRemoteHost();
assertEquals("testapi.us-east-1.elb.amazonaws.com", host);
}

private AwsProxyRequestBuilder getRequestWithHeaders() {
return new AwsProxyRequestBuilder("/hello", "GET")
.header(CUSTOM_HEADER_KEY, CUSTOM_HEADER_VALUE)
Expand Down
3 changes: 2 additions & 1 deletion ...c/test/java/com/amazonaws/serverless/proxy/internal/testutils/AwsProxyRequestBuilder.java
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Expand Up @@ -70,7 +70,8 @@ public AwsProxyRequestBuilder(AwsProxyRequest req) {

public AwsProxyRequestBuilder(String path, String httpMethod) {
this.request = new AwsProxyRequest();
this.request.setMultiValueHeaders(new Headers()); // avoid NPE
this.request.setMultiValueHeaders(new Headers());// avoid NPE
this.request.setHeaders(new SingleValueHeaders());
this.request.setHttpMethod(httpMethod);
this.request.setPath(path);
this.request.setMultiValueQueryStringParameters(new MultiValuedTreeMap<>());
Expand Down