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Posted to dev@tomcat.apache.org by ma...@apache.org on 2020/12/07 17:18:22 UTC
[tomcat] branch master updated: Fix BZ 60781 Escape access log
output where httpd does (#384)
This is an automated email from the ASF dual-hosted git repository.
markt pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/tomcat.git
The following commit(s) were added to refs/heads/master by this push:
new a9d67fd Fix BZ 60781 Escape access log output where httpd does (#384)
a9d67fd is described below
commit a9d67fd7c08272c01b870edd24d001740d88e5f6
Author: Mark Thomas <ma...@apache.org>
AuthorDate: Mon Dec 7 17:18:06 2020 +0000
Fix BZ 60781 Escape access log output where httpd does (#384)
Fix BZ 60781 Escape access log output where httpd does
https://bz.apache.org/bugzilla/show_bug.cgi?id=60781
Isn't quite that simple as httpd and Tomact support slightly
different things and validate at different points. See the
code comments.
---
.../catalina/valves/AbstractAccessLogValve.java | 118 +++++++++++++++++++--
.../valves/TestAbstractAccessLogValveEscape.java | 66 ++++++++++++
webapps/docs/changelog.xml | 5 +
webapps/docs/config/valve.xml | 23 ++--
4 files changed, 196 insertions(+), 16 deletions(-)
diff --git a/java/org/apache/catalina/valves/AbstractAccessLogValve.java b/java/org/apache/catalina/valves/AbstractAccessLogValve.java
index 7421d33..6672370 100644
--- a/java/org/apache/catalina/valves/AbstractAccessLogValve.java
+++ b/java/org/apache/catalina/valves/AbstractAccessLogValve.java
@@ -52,6 +52,7 @@ import org.apache.coyote.RequestInfo;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.apache.tomcat.util.ExceptionUtils;
+import org.apache.tomcat.util.buf.HexUtils;
import org.apache.tomcat.util.collections.SynchronizedStack;
import org.apache.tomcat.util.net.IPv6Utils;
@@ -966,7 +967,7 @@ public abstract class AbstractAccessLogValve extends ValveBase implements Access
if (request != null) {
String value = request.getRemoteUser();
if (value != null) {
- buf.append(value);
+ escapeAndAppend(value, buf);
} else {
buf.append('-');
}
@@ -1478,9 +1479,10 @@ public abstract class AbstractAccessLogValve extends ValveBase implements Access
Response response, long time) {
Enumeration<String> iter = request.getHeaders(header);
if (iter.hasMoreElements()) {
- buf.append(iter.nextElement());
+ escapeAndAppend(iter.nextElement(), buf);
while (iter.hasMoreElements()) {
- buf.append(',').append(iter.nextElement());
+ buf.append(',');
+ escapeAndAppend(iter.nextElement(), buf);
}
return;
}
@@ -1511,7 +1513,7 @@ public abstract class AbstractAccessLogValve extends ValveBase implements Access
}
}
}
- buf.append(value);
+ escapeAndAppend(value, buf);
}
}
@@ -1531,9 +1533,10 @@ public abstract class AbstractAccessLogValve extends ValveBase implements Access
if (null != response) {
Iterator<String> iter = response.getHeaders(header).iterator();
if (iter.hasNext()) {
- buf.append(iter.next());
+ escapeAndAppend(iter.next(), buf);
while (iter.hasNext()) {
- buf.append(',').append(iter.next());
+ buf.append(',');
+ escapeAndAppend(iter.next(), buf);
}
return;
}
@@ -1563,9 +1566,9 @@ public abstract class AbstractAccessLogValve extends ValveBase implements Access
}
if (value != null) {
if (value instanceof String) {
- buf.append((String) value);
+ escapeAndAppend((String) value, buf);
} else {
- buf.append(value.toString());
+ escapeAndAppend(value.toString(), buf);
}
} else {
buf.append('-');
@@ -1597,9 +1600,9 @@ public abstract class AbstractAccessLogValve extends ValveBase implements Access
}
if (value != null) {
if (value instanceof String) {
- buf.append((String) value);
+ escapeAndAppend((String) value, buf);
} else {
- buf.append(value.toString());
+ escapeAndAppend(value.toString(), buf);
}
} else {
buf.append('-');
@@ -1805,4 +1808,99 @@ public abstract class AbstractAccessLogValve extends ValveBase implements Access
return new StringElement("???" + pattern + "???");
}
}
+
+
+ /*
+ * This method is intended to mimic the escaping performed by httpd and
+ * mod_log_config. mod_log_config escapes more elements than indicated by the
+ * documentation. See:
+ * https://github.com/apache/httpd/blob/trunk/modules/loggers/mod_log_config.c
+ *
+ * The following escaped elements are not supported by Tomcat:
+ * - %C cookie value (see %{}c below)
+ * - %e environment variable
+ * - %f filename
+ * - %l remote logname (always logs "-")
+ * - %n note
+ * - %R handler
+ * - %ti trailer request header
+ * - %to trailer response header
+ * - %V server name per UseCanonicalName setting
+ *
+ * The following escaped elements are not escaped in Tomcat because values
+ * that would require escaping are rejected before they reach the
+ * AccessLogValve:
+ * - %h remote host
+ * - %H request protocol
+ * - %m request method
+ * - %q query string
+ * - %r request line
+ * - %U request URI
+ * - %v canonical server name
+ *
+ * The following escaped elements are supported by Tomcat:
+ * - %{}i request header
+ * - %{}o response header
+ * - %u remote user
+ *
+ * The following additional Tomcat elements are escaped for consistency:
+ * - %{}c cookie value
+ * - %{}r request attribute
+ * - %{}s session attribute
+ *
+ * giving a total of 6 elements that are escaped in Tomcat.
+ *
+ * Quoting from the httpd docs:
+ * "...non-printable and other special characters in %r, %i and %o are
+ * escaped using \xhh sequences, where hh stands for the hexadecimal
+ * representation of the raw byte. Exceptions from this rule are " and \,
+ * which are escaped by prepending a backslash, and all whitespace
+ * characters, which are written in their C-style notation (\n, \t, etc)."
+ *
+ * Reviewing the httpd code, characters with the high bit set are escaped.
+ * The httpd is assuming a single byte encoding which may not be true for
+ * Tomcat so Tomcat uses the Java \\uXXXX encoding.
+ */
+ protected static void escapeAndAppend(String input, CharArrayWriter dest) {
+ if (input == null || input.isEmpty()) {
+ dest.append('-');
+ return;
+ }
+
+ for (char c : input.toCharArray()) {
+ switch (c) {
+ // " and \
+ case '\\':
+ dest.append("\\\\");
+ break;
+ case '\"':
+ dest.append("\\\"");
+ break;
+ // Standard C escapes for whitespace (not all standard C escapes)
+ case '\f':
+ dest.append("\\f");
+ break;
+ case '\n':
+ dest.append("\\n");
+ break;
+ case '\r':
+ dest.append("\\r");
+ break;
+ case '\t':
+ dest.append("\\t");
+ break;
+ case '\u000b':
+ dest.append("\\v");
+ break;
+ default:
+ // Control, delete (127) or above 127
+ if (c < 32 || c > 126) {
+ dest.append("\\u");
+ dest.append(HexUtils.toHexString(c));
+ } else {
+ dest.append(c);
+ }
+ }
+ }
+ }
}
diff --git a/test/org/apache/catalina/valves/TestAbstractAccessLogValveEscape.java b/test/org/apache/catalina/valves/TestAbstractAccessLogValveEscape.java
new file mode 100644
index 0000000..b0e0f3f
--- /dev/null
+++ b/test/org/apache/catalina/valves/TestAbstractAccessLogValveEscape.java
@@ -0,0 +1,66 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.catalina.valves;
+
+import java.io.CharArrayWriter;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameter;
+import org.junit.runners.Parameterized.Parameters;
+
+
+@RunWith(Parameterized.class)
+public class TestAbstractAccessLogValveEscape {
+
+ @Parameters(name = "{index}: [{0}]")
+ public static Collection<Object[]> parameters() {
+
+ List<Object[]> parameters = new ArrayList<>();
+
+ parameters.add(new String[] { null, "-" });
+ parameters.add(new String[] { "", "-" });
+ parameters.add(new String[] { "ok", "ok" });
+ parameters.add(new String[] { "o\tk", "o\\tk" });
+ parameters.add(new String[] { "o\u0002k", "o\\u0002k" });
+ parameters.add(new String[] { "o\u007fk", "o\\u007fk" });
+ parameters.add(new String[] { "o\u0080k", "o\\u0080k" });
+ parameters.add(new String[] { "o\u00ffk", "o\\u00ffk" });
+ parameters.add(new String[] { "o\"k", "o\\\"k" });
+
+ return parameters;
+ }
+
+ @Parameter(0)
+ public String input;
+
+ @Parameter(1)
+ public String expected;
+
+
+ @Test
+ public void testEscape() {
+ CharArrayWriter actual = new CharArrayWriter();
+ AbstractAccessLogValve.escapeAndAppend(input, actual);
+ Assert.assertEquals(expected, actual.toString());
+ }
+}
diff --git a/webapps/docs/changelog.xml b/webapps/docs/changelog.xml
index 2fe02eb..18638b7 100644
--- a/webapps/docs/changelog.xml
+++ b/webapps/docs/changelog.xml
@@ -106,6 +106,11 @@
<section name="Tomcat 10.0.1 (markt)" rtext="in development">
<subsection name="Catalina">
<changelog>
+ <fix>
+ <bug>60781</bug>: Escape elements in the access log that need to be
+ escaped for the access log to be parsed unambiguously.
+ (fschumacher/markt)
+ </fix>
<add>
<bug>64110</bug>: Add support for additional TLS related request
attributes that provide details of the protocols and ciphers requested
diff --git a/webapps/docs/config/valve.xml b/webapps/docs/config/valve.xml
index 58ccd2c..4f14763 100644
--- a/webapps/docs/config/valve.xml
+++ b/webapps/docs/config/valve.xml
@@ -301,7 +301,7 @@
<li><b>%s</b> - HTTP status code of the response</li>
<li><b>%S</b> - User session ID</li>
<li><b>%t</b> - Date and time, in Common Log Format</li>
- <li><b>%u</b> - Remote user that was authenticated (if any), else '-'</li>
+ <li><b>%u</b> - Remote user that was authenticated (if any), else '-' (escaped if required)</li>
<li><b>%U</b> - Requested URL path</li>
<li><b>%v</b> - Local server name</li>
<li><b>%D</b> - Time taken to process the request in microseconds</li>
@@ -326,11 +326,11 @@
syntax. Each of them can be used multiple times with different <code>xxx</code> keys:
</p>
<ul>
- <li><b><code>%{xxx}i</code></b> write value of incoming header with name <code>xxx</code></li>
- <li><b><code>%{xxx}o</code></b> write value of outgoing header with name <code>xxx</code></li>
- <li><b><code>%{xxx}c</code></b> write value of cookie with name <code>xxx</code></li>
- <li><b><code>%{xxx}r</code></b> write value of ServletRequest attribute with name <code>xxx</code></li>
- <li><b><code>%{xxx}s</code></b> write value of HttpSession attribute with name <code>xxx</code></li>
+ <li><b><code>%{xxx}i</code></b> write value of incoming header with name <code>xxx</code> (escaped if required)</li>
+ <li><b><code>%{xxx}o</code></b> write value of outgoing header with name <code>xxx</code> (escaped if required)</li>
+ <li><b><code>%{xxx}c</code></b> write value of cookie with name <code>xxx</code> (escaped if required)</li>
+ <li><b><code>%{xxx}r</code></b> write value of ServletRequest attribute with name <code>xxx</code> (escaped if required)</li>
+ <li><b><code>%{xxx}s</code></b> write value of HttpSession attribute with name <code>xxx</code> (escaped if required)</li>
<li><b><code>%{xxx}p</code></b> write local (server) port (<code>xxx==local</code>) or
remote (client) port (<code>xxx=remote</code>)</li>
<li><b><code>%{xxx}t</code></b> write timestamp at the end of the request formatted using the
@@ -362,6 +362,17 @@
<p>By adding multiple <code>%{xxx}t</code> tokens to the pattern, one can
also log both timestamps.</p>
+ <p>Escaping is applied as follows:</p>
+ <ul>
+ <li><code>"</code> is escaped as <code>\"</code></li>
+ <li><code>\</code> is escaped as <code>\\</code></li>
+ <li>Standard C escaping are used for <code>\f</code>, <code>\n</code>,
+ <code>\r</code>, <code>\t</code> and <code>\v</code></li>
+ <li>Any other control characters or characters with code points above 127
+ are encoded using the standard Java unicode escaping
+ (<code>\uXXXX</code>)</li>
+ </ul>
+
<p>The shorthand pattern <code>pattern="common"</code>
corresponds to the Common Log Format defined by
<strong>'%h %l %u %t "%r" %s %b'</strong>.</p>
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