On Thu, Jan 16, 2025 at 5:42 PM Mark Thomas <[email protected]> wrote:
>
> On 16/01/2025 16:38, [email protected] wrote:
> > This is an automated email from the ASF dual-hosted git repository.
> >
> > markt pushed a commit to branch 9.0.x
> > in repository https://gitbox.apache.org/repos/asf/tomcat.git
> >
> >
> > The following commit(s) were added to refs/heads/9.0.x by this push:
> > new 427732ef8e Automate protection for CVE-2024-56337
> > 427732ef8e is described below
> >
> > commit 427732ef8ee7f707a32734a13a926a2d070b8ba9
> > Author: Mark Thomas <[email protected]>
> > AuthorDate: Thu Jan 16 16:37:06 2025 +0000
> >
> > Automate protection for CVE-2024-56337
> >
> > If there is a potentially vulnerable web application (Java < 21,
> > WebResourceSet configured for read/write, case-insensitive file system)
> > ensure that the JVM behaves as if sun.io.useCanonCaches is false. If
> > that cannot be ensured, prevent the potentially vulnerable web
> > applications from starting.
>
> I looked at various approaches for this and settled on this one after a
> few experiements. I wanted to give folks a little time for feedback
> before porting it to 10.1.x and 11.0.x. I won't port it to main since
> that requires Java 21 where the problematic JVM setting doesn't exist.
Ok, it works.
Rémy
> Mark
>
> > ---
> > bin/catalina.bat | 7 +++
> > bin/catalina.sh | 7 +++
> > .../catalina/webresources/DirResourceSet.java | 29 +++++++++
> > .../catalina/webresources/LocalStrings.properties | 2 +
> > .../org/apache/tomcat/util/compat/Jre21Compat.java | 14 +++++
> > java/org/apache/tomcat/util/compat/JreCompat.java | 69
> > +++++++++++++++++++++-
> > .../tomcat/util/compat/LocalStrings.properties | 3 +
> > webapps/docs/changelog.xml | 9 +++
> > 8 files changed, 139 insertions(+), 1 deletion(-)
> >
> > diff --git a/bin/catalina.bat b/bin/catalina.bat
> > index 05704d6115..9fc3da0369 100755
> > --- a/bin/catalina.bat
> > +++ b/bin/catalina.bat
> > @@ -219,6 +219,13 @@ rem Register custom URL handlers
> > rem Do this here so custom URL handles (specifically 'war:...') can be
> > used in the security policy
> > set "JAVA_OPTS=%JAVA_OPTS%
> > -Djava.protocol.handler.pkgs=org.apache.catalina.webresources"
> >
> > +rem Disable the global canonical file name cache to protect against
> > CVE-2024-56337
> > +rem Note: The cache is disabled by default in Java 12 to 20 inclusive
> > +rem The cache is removed in Java 21 onwards
> > +rem Need to set this here as java.io.FileSystem caches this in a static
> > field during class
> > +rem initialisation so it needs to be set before any file system access
> > +set "JAVA_OPTS=%JAVA_OPTS% -Dsun.io.useCanonCaches=false"
> > +
> > rem Check for the deprecated LOGGING_CONFIG
> > rem Only use it if CATALINA_LOGGING_CONFIG is not set and LOGGING_CONFIG
> > starts with "-D..."
> > if not "%LOGGING_CONFIG:~0,2%"=="-D" goto noLoggingDeprecation
> > diff --git a/bin/catalina.sh b/bin/catalina.sh
> > index 3a2ffdafa0..8d07001214 100755
> > --- a/bin/catalina.sh
> > +++ b/bin/catalina.sh
> > @@ -268,6 +268,13 @@ JAVA_OPTS="$JAVA_OPTS $JSSE_OPTS"
> > # Do this here so custom URL handles (specifically 'war:...') can be used
> > in the security policy
> > JAVA_OPTS="$JAVA_OPTS
> > -Djava.protocol.handler.pkgs=org.apache.catalina.webresources"
> >
> > +# Disable the global canonical file name cache to protect against
> > CVE-2024-56337
> > +# Note: The cache is disabled by default in Java 12 to 20 inclusive
> > +# The cache is removed in Java 21 onwards
> > +# Need to set this here as java.io.FileSystem caches this in a static
> > field during class
> > +# initialisation so it needs to be set before any file system access
> > +JAVA_OPTS="$JAVA_OPTS -Dsun.io.useCanonCaches=false"
> > +
> > # Check for the deprecated LOGGING_CONFIG
> > # Only use it if CATALINA_LOGGING_CONFIG is not set and LOGGING_CONFIG
> > starts with "-D..."
> > if [ -z "$CATALINA_LOGGING_CONFIG" ]; then
> > diff --git a/java/org/apache/catalina/webresources/DirResourceSet.java
> > b/java/org/apache/catalina/webresources/DirResourceSet.java
> > index 512adf8b8a..4f39e87378 100644
> > --- a/java/org/apache/catalina/webresources/DirResourceSet.java
> > +++ b/java/org/apache/catalina/webresources/DirResourceSet.java
> > @@ -36,6 +36,7 @@ import
> > org.apache.catalina.WebResourceRoot.ResourceSetType;
> > import org.apache.catalina.util.ResourceSet;
> > import org.apache.juli.logging.Log;
> > import org.apache.juli.logging.LogFactory;
> > +import org.apache.tomcat.util.compat.JreCompat;
> > import org.apache.tomcat.util.http.RequestUtil;
> >
> > /**
> > @@ -335,6 +336,34 @@ public class DirResourceSet extends
> > AbstractFileResourceSet implements WebResour
> > }
> > }
> > }
> > + // Check for exposure to CVE-2024-56337
> > + if (caseSensitive) {
> > + // CVE-2024-56337 (nor CVE-2024-50379) is not exploitable on a
> > case sensitive file system
> > + return;
> > + }
> > + if (isReadOnly()) {
> > + // CVE-2024-56337 (nor CVE-2024-50379) is not exploitable on a
> > read-only ResourceSet
> > + return;
> > + }
> > + if (JreCompat.getInstance().isCanonCachesDisabled()) {
> > + // CVE-2024-56337 (nor CVE-2024-50379) is not exploitable if
> > the canonical file name cache is disabled
> > + return;
> > + }
> > + // This ResourceSet may be exposed to CVE-2024-56337.
> > + if (JreCompat.getInstance().disableCanonCaches()) {
> > + /*
> > + * The canonical file name cache was enabled and is now
> > disabled.
> > + */
> > + log.warn(sm.getString("dirResourceSet.canonCaches.disabled",
> > getFileBase(),
> > + getRoot().getContext().getName()));
> > + } else {
> > + /*
> > + * The canonical file name cache could not be disabled (or
> > Tomcat cannot confirm it has been disabled). This
> > + * ResourceSet may be exposed to CVE-2024-56337.
> > + */
> > + throw new
> > IllegalStateException(sm.getString("dirResourceSet.canonCaches.enabled",
> > getFileBase(),
> > + getRoot().getContext().getName()));
> > + }
> > }
> >
> >
> > diff --git a/java/org/apache/catalina/webresources/LocalStrings.properties
> > b/java/org/apache/catalina/webresources/LocalStrings.properties
> > index 20bcdf5330..2590428e09 100644
> > --- a/java/org/apache/catalina/webresources/LocalStrings.properties
> > +++ b/java/org/apache/catalina/webresources/LocalStrings.properties
> > @@ -36,6 +36,8 @@ cachedResource.invalidURL=Unable to create an instance of
> > CachedResourceURLStrea
> >
> > classpathUrlStreamHandler.notFound=Unable to load the resource [{0}]
> > using the thread context class loader or the current class''s class loader
> >
> > +dirResourceSet.canonCaches.disabled=Disabled the global canonical file
> > name cache to protect against CVE-2024-56337 when starting the
> > WebResourceSet at [{0}] which is part of the web application [{1}]
> > +dirResourceSet.canonCaches.enabled=Unable to disable the global canonical
> > file name cache or confirm that it is disabled when starting the
> > WebResourceSet at [{0}] which is part of the web application [{1}]. The
> > WebResourceSet may be exposed to CVE-2024-56337.
> > dirResourceSet.isCaseSensitive.fail=Error trying to determine if file
> > system at [{0}] is case sensitive so assuming it is not case sensitive
> > dirResourceSet.manifestFail=Failed to read manifest from [{0}]
> > dirResourceSet.notDirectory=The directory specified by base and internal
> > path [{0}]{1}[{2}] does not exist.
> > diff --git a/java/org/apache/tomcat/util/compat/Jre21Compat.java
> > b/java/org/apache/tomcat/util/compat/Jre21Compat.java
> > index c534ea4e2d..ee01f3e28e 100644
> > --- a/java/org/apache/tomcat/util/compat/Jre21Compat.java
> > +++ b/java/org/apache/tomcat/util/compat/Jre21Compat.java
> > @@ -104,4 +104,18 @@ public class Jre21Compat extends Jre19Compat {
> > throw new CompletionException(e);
> > }
> > }
> > +
> > +
> > + @Override
> > + public boolean isCanonCachesDisabled() {
> > + // The cache has been removed in Java 21
> > + return true;
> > + }
> > +
> > +
> > + @Override
> > + public boolean disableCanonCaches() {
> > + // The cache has been removed in Java 21
> > + return true;
> > + }
> > }
> > diff --git a/java/org/apache/tomcat/util/compat/JreCompat.java
> > b/java/org/apache/tomcat/util/compat/JreCompat.java
> > index 66b11684c7..135b7bc21c 100644
> > --- a/java/org/apache/tomcat/util/compat/JreCompat.java
> > +++ b/java/org/apache/tomcat/util/compat/JreCompat.java
> > @@ -37,6 +37,8 @@ import javax.net.ssl.SSLEngine;
> > import javax.net.ssl.SSLParameters;
> > import javax.security.auth.Subject;
> >
> > +import org.apache.juli.logging.Log;
> > +import org.apache.juli.logging.LogFactory;
> > import org.apache.tomcat.util.res.StringManager;
> >
> > /**
> > @@ -45,6 +47,9 @@ import org.apache.tomcat.util.res.StringManager;
> > */
> > public class JreCompat {
> >
> > + private static final Log log = LogFactory.getLog(Jre21Compat.class);
> > + private static final StringManager sm =
> > StringManager.getManager(JreCompat.class);
> > +
> > private static final int RUNTIME_MAJOR_VERSION = 8;
> >
> > private static final JreCompat instance;
> > @@ -55,8 +60,8 @@ public class JreCompat {
> > private static final boolean jre19Available;
> > private static final boolean jre21Available;
> > private static final boolean jre22Available;
> > - private static final StringManager sm =
> > StringManager.getManager(JreCompat.class);
> >
> > + private static final Field useCanonCachesField;
> > protected static final Method setApplicationProtocolsMethod;
> > protected static final Method getApplicationProtocolMethod;
> >
> > @@ -119,6 +124,21 @@ public class JreCompat {
> > }
> > jre11Available = instance.jarFileRuntimeMajorVersion() >= 11;
> >
> > + Field f1 = null;
> > + try {
> > + Class<?> clazz = Class.forName("java.io.FileSystem");
> > + f1 = clazz.getDeclaredField("useCanonCaches");
> > + f1.setAccessible(true);
> > + } catch (ReflectiveOperationException | IllegalArgumentException
> > e) {
> > + /*
> > + * Log at debug level as this will only be an issue if the
> > field needs to be accessed and most
> > + * configurations will not need to do so. Appropriate warnings
> > will be logged if an attempt is made to use
> > + * the field when it could not be found/accessed.
> > + */
> > + log.debug(sm.getString("jreCompat.useCanonCaches.init"), e);
> > + }
> > + useCanonCachesField = f1;
> > +
> > Method m1 = null;
> > Method m2 = null;
> > try {
> > @@ -482,4 +502,51 @@ public class JreCompat {
> > throw new CompletionException(e);
> > }
> > }
> > +
> > +
> > + /*
> > + * The behaviour of the canonical file cache varies by Java version.
> > + *
> > + * The cache was removed in Java 21 so these methods and the
> > associated code can be removed once the minimum Java
> > + * version is 21.
> > + *
> > + * For 12 <= Java <= 20, the cache was present but disabled by
> > default. Since the user may have changed the default
> > + * Tomcat has to assume the cache is enabled unless proven otherwise.
> > + *
> > + * For Java < 12, the cache was enabled by default. Tomcat assumes the
> > cache is enabled unless proven otherwise.
> > + */
> > + public boolean isCanonCachesDisabled() {
> > + if (useCanonCachesField == null) {
> > + // No need to log a warning. The warning will be logged when
> > trying to disable the cache.
> > + return false;
> > + }
> > + boolean result = false;
> > + try {
> > + result = !((Boolean)
> > useCanonCachesField.get(null)).booleanValue();
> > + } catch (ReflectiveOperationException e) {
> > + // No need to log a warning. The warning will be logged when
> > trying to disable the cache.
> > + }
> > + return result;
> > + }
> > +
> > +
> > + /**
> > + * Disable the global canonical file cache.
> > + *
> > + * @return {@code true} if the global canonical file cache was already
> > disabled prior to this call or was disabled
> > + * as a result of this call, otherwise {@code false}
> > + */
> > + public boolean disableCanonCaches() {
> > + if (useCanonCachesField == null) {
> > + log.warn(sm.getString("jreCompat.useCanonCaches.none"));
> > + return false;
> > + }
> > + try {
> > + useCanonCachesField.set(null, Boolean.TRUE);
> > + } catch (ReflectiveOperationException | IllegalArgumentException
> > e) {
> > + log.warn(sm.getString("jreCompat.useCanonCaches.failed"), e);
> > + return false;
> > + }
> > + return true;
> > + }
> > }
> > diff --git a/java/org/apache/tomcat/util/compat/LocalStrings.properties
> > b/java/org/apache/tomcat/util/compat/LocalStrings.properties
> > index ad858297e9..4b33b7a4aa 100644
> > --- a/java/org/apache/tomcat/util/compat/LocalStrings.properties
> > +++ b/java/org/apache/tomcat/util/compat/LocalStrings.properties
> > @@ -37,3 +37,6 @@ jreCompat.noApplicationProtocol=Java Runtime does not
> > support SSLEngine.getAppli
> > jreCompat.noApplicationProtocols=Java Runtime does not support
> > SSLParameters.setApplicationProtocols(). You must use Java 9 to use this
> > feature.
> > jreCompat.noUnixDomainSocket=Java Runtime does not support Unix domain
> > sockets. You must use Java 16 or later to use this feature.
> > jreCompat.noVirtualThreads=Java Runtime does not support virtual threads.
> > You must use Java 21 or later to use this feature.
> > +jreCompat.useCanonCaches.failed=Failed to set the
> > java.io.FileSystem.useCanonCaches static field
> > +jreCompat.useCanonCaches.init=Unable to create a reference to the
> > java.io.FileSystem.useCanonCaches static field
> > +jreCompat.useCanonCaches.none=No reference to the
> > java.io.FileSystem.useCanonCaches static field available. Enable debug
> > logging for more information.
> > diff --git a/webapps/docs/changelog.xml b/webapps/docs/changelog.xml
> > index 4c54b39903..1861714fcc 100644
> > --- a/webapps/docs/changelog.xml
> > +++ b/webapps/docs/changelog.xml
> > @@ -140,6 +140,15 @@
> > Improve checks for <code>WEB-INF</code> and <code>META-INF</code>
> > in
> > the WebDAV servlet. Based on a patch submitted by Chenjp. (remm)
> > </fix>
> > + <add>
> > + Add a check to ensure that, if one or more web applications are
> > + potentially vulnerable to CVE-2024-56337, the JVM has been
> > configured to
> > + protect against the vulnerability and to configure the JVM
> > correctly if
> > + not. Where one or more web applications are potentially vulnerable
> > to
> > + CVE-2004-56337 and the JVM cannot be correctly configured or it
> > cannot
> > + be confirmed that the JVM has been correctly configured, prevent
> > the
> > + impacted web applications from starting. (markt)
> > + </add>
> > </changelog>
> > </subsection>
> > <subsection name="Coyote">
> >
> >
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> >
>
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