From eb5c094e5560764cda436362254997511a3ca1f6 Mon Sep 17 00:00:00 2001
From: Mark Thomas <markt@apache.org>
Date: Thu, 5 Oct 2023 20:51:48 +0100
Subject: [PATCH] Align processing of trailer headers with standard processing

---
 .../apache/coyote/http11/Http11InputBuffer.java   |  8 +++++++-
 .../coyote/http11/filters/ChunkedInputFilter.java | 15 ++++++++++++++-
 .../coyote/http11/filters/LocalStrings.properties |  2 ++
 webapps/docs/changelog.xml                        |  3 +++
 4 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/java/org/apache/coyote/http11/Http11InputBuffer.java b/java/org/apache/coyote/http11/Http11InputBuffer.java
index 78c9c1463b57..1ae9eba04bcc 100644
--- a/java/org/apache/coyote/http11/Http11InputBuffer.java
+++ b/java/org/apache/coyote/http11/Http11InputBuffer.java
@@ -826,6 +826,12 @@ private boolean fill(boolean block) throws IOException {
      */
     private HeaderParseStatus parseHeader() throws IOException {
 
+        /*
+         * Implementation note: Any changes to this method probably need to be echoed in
+         * ChunkedInputFilter.parseHeader(). Why not use a common implementation? In short, this code uses non-blocking
+         * reads whereas ChunkedInputFilter using blocking reads. The code is just different enough that a common
+         * implementation wasn't viewed as practical.
+         */
         while (headerParsePos == HeaderParsePosition.HEADER_START) {
 
             // Read new bytes if needed
@@ -968,7 +974,7 @@ private HeaderParseStatus parseHeader() throws IOException {
                     } else if (prevChr == Constants.CR) {
                         // Invalid value - also need to delete header
                         return skipLine();
-                    } else if (chr != Constants.HT && HttpParser.isControl(chr)) {
+                    } else if (HttpParser.isControl(chr) && chr != Constants.HT) {
                         // Invalid value - also need to delete header
                         return skipLine();
                     } else if (chr == Constants.SP || chr == Constants.HT) {
diff --git a/java/org/apache/coyote/http11/filters/ChunkedInputFilter.java b/java/org/apache/coyote/http11/filters/ChunkedInputFilter.java
index 7fe17f7b9df1..3e844afb1161 100644
--- a/java/org/apache/coyote/http11/filters/ChunkedInputFilter.java
+++ b/java/org/apache/coyote/http11/filters/ChunkedInputFilter.java
@@ -30,6 +30,7 @@
 import org.apache.coyote.http11.InputFilter;
 import org.apache.tomcat.util.buf.ByteChunk;
 import org.apache.tomcat.util.buf.HexUtils;
+import org.apache.tomcat.util.http.parser.HttpParser;
 import org.apache.tomcat.util.net.ApplicationBufferHandler;
 import org.apache.tomcat.util.res.StringManager;
 
@@ -443,6 +444,13 @@ protected void parseEndChunk() throws IOException {
 
     private boolean parseHeader() throws IOException {
 
+        /*
+         * Implementation note: Any changes to this method probably need to be echoed in
+         * Http11InputBuffer.parseHeader(). Why not use a common implementation? In short, this code uses blocking
+         * reads whereas Http11InputBuffer using non-blocking reads. The code is just different enough that a common
+         * implementation wasn't viewed as practical.
+         */
+
         Map<String,String> headers = request.getTrailerFields();
 
         byte chr = 0;
@@ -489,6 +497,9 @@ private boolean parseHeader() throws IOException {
 
             if (chr == Constants.COLON) {
                 colon = true;
+            } else if (!HttpParser.isToken(chr)) {
+                // Non-token characters are illegal in header names
+                throw new IOException(sm.getString("chunkedInputFilter.invalidTrailerHeaderName"));
             } else {
                 trailingHeaders.append(chr);
             }
@@ -550,7 +561,9 @@ private boolean parseHeader() throws IOException {
                 if (chr == Constants.CR || chr == Constants.LF) {
                     parseCRLF(true);
                     eol = true;
-                } else if (chr == Constants.SP) {
+                } else if (HttpParser.isControl(chr) && chr != Constants.HT) {
+                    throw new IOException(sm.getString("chunkedInputFilter.invalidTrailerHeaderValue"));
+                } else if (chr == Constants.SP || chr == Constants.HT) {
                     trailingHeaders.append(chr);
                 } else {
                     trailingHeaders.append(chr);
diff --git a/java/org/apache/coyote/http11/filters/LocalStrings.properties b/java/org/apache/coyote/http11/filters/LocalStrings.properties
index 72dc788bc5a6..3114a87d0abe 100644
--- a/java/org/apache/coyote/http11/filters/LocalStrings.properties
+++ b/java/org/apache/coyote/http11/filters/LocalStrings.properties
@@ -24,6 +24,8 @@ chunkedInputFilter.invalidCrlfCRCR=Invalid end of line sequence (CRCR)
 chunkedInputFilter.invalidCrlfNoCR=Invalid end of line sequence (No CR before LF)
 chunkedInputFilter.invalidCrlfNoData=Invalid end of line sequence (no data available to read)
 chunkedInputFilter.invalidHeader=Invalid chunk header
+chunkedInputFilter.invalidTrailerHeaderName=Invalid trailer header name (non-token character in name)
+chunkedInputFilter.invalidTrailerHeaderValue=Invalid trailer header value (control character in value)
 chunkedInputFilter.maxExtension=maxExtensionSize exceeded
 chunkedInputFilter.maxTrailer=maxTrailerSize exceeded
 
diff --git a/webapps/docs/changelog.xml b/webapps/docs/changelog.xml
index de54d83039d7..73a337dcfa1f 100644
--- a/webapps/docs/changelog.xml
+++ b/webapps/docs/changelog.xml
@@ -170,6 +170,9 @@
         <code>newPushBuilder()</code> will always return <code>null</code>.
         (markt)
       </update>
+      <fix>
+        Align validation of HTTP trailer fields with standard fields. (markt)
+      </fix>
     </changelog>
   </subsection>
   <subsection name="Jasper">